WorldWideScience

Sample records for matter hyperintensities diffusion

  1. Employing visual analytics to aid the design of white matter hyperintensity classifiers

    NARCIS (Netherlands)

    Raidou, Renata Georgia; Kuijf, Hugo J.; Sepasian, Neda; Pezzotti, Nicola; Bouvy, Willem H.; Breeuwer, Marcel; Vilanova, Anna

    2016-01-01

    Accurate segmentation of brain white matter hyperintensities (WMHs) is important for prognosis and disease monitoring. To this end,classifiers are often trained – usually,using T1 and FLAIR weighted MR images. Incorporating additional features,derived from diffusion weighted MRI,could improve

  2. The hidden-Markov brain: comparison and inference of white matter hyperintensities on magnetic resonance imaging (MRI)

    Science.gov (United States)

    Pham, Tuan D.; Salvetti, Federica; Wang, Bing; Diani, Marco; Heindel, Walter; Knecht, Stefan; Wersching, Heike; Baune, Bernhard T.; Berger, Klaus

    2011-02-01

    Rating and quantification of cerebral white matter hyperintensities on magnetic resonance imaging (MRI) are important tasks in various clinical and scientific settings. As manual evaluation is time consuming and imprecise, much effort has been made to automate the quantification of white matter hyperintensities. There is rarely any report that attempts to study the similarity/dissimilarity of white matter hyperintensity patterns that have different sizes, shapes and spatial localizations on the MRI. This paper proposes an original computational neuroscience framework for such a conceptual study with a standpoint that the prior knowledge about white matter hyperintensities can be accumulated and utilized to enable a reliable inference of the rating of a new white matter hyperintensity observation. This computational approach for rating inference of white matter hyperintensities, which appears to be the first study, can be utilized as a computerized rating-assisting tool and can be very economical for diagnostic evaluation of brain tissue lesions.

  3. Marchiafava-Bignami disease with hyperintensity on late diffusion-weighted imaging

    International Nuclear Information System (INIS)

    Iwai, Takayasu; Matsuo, Koushun; Morii-Kitani, Fukiko; Azuma, Fumiko; Matsuo, Hisayasu; Takada, Masahiko; Nakagawa, Masanori; Mizuno, Toshiki; Yamada, Kei

    2014-01-01

    A 69-year-old man with a decades-long history of chronic alcohol consumption was admitted with gait disturbance (short steps and spasticity), deterioration of activity, and stuporous consciousness. Head magnetic resonance imaging (MRI) revealed hyperintensity on fluid-attenuated inversion recovery imaging in the corpus callosum and frontal white matter. The lesion later became more apparent on diffusion-weighted imaging. The clinical diagnosis was Marchiafava-Bignami disease (MBD). As temporary treatment, refraining from alcohol consumption and administration of vitamins were prescribed. The condition of the patient gradually improved. The purposes of this study were to demonstrate the clinical and radiological variety of MBD and to identify practical methods of treatment of this pathology

  4. Hyperintensity on diffusion weighted image along ipsilateral cortical spinal tract after cerebral ischemic stroke: A diffusion tensor analysis

    International Nuclear Information System (INIS)

    Liu Xiang; Tian Wei; Li Lilin; Kolar, Balasubramanya; Qiu Xing; Chen, Feng; Dogra, Vikram S.

    2012-01-01

    Purpose: Hyperintensity along the ipsilateral cortical spinal tract (CST) on a diffusion weighted imaging (DWI) has been reported to may be associated with motor disability after brain infarction and can be misdiagnosed as a new infarction. However, the underlying patho-physiology related to this finding is not clear. The goal of our study was to analyze the diffusion tensor imaging (DTI) changes in patients with this hyperintensity. Materials and methods: Eight patients (50 ± 10 years) who exhibited hyperintensity on DWI along ipsilateral CST from 3 to 21 days after stroke onset were reviewed as positive group, including 5 patients with serial DTI examinations. Twelve patients without hyperintensity during the matched examination time were classified as reference group. The apparent diffusion coefficient (ADC), fractional anisotropy (FA), and eigenvalues and their ratios (ipsilateral/contralateral value) in cerebral peduncle were measured, their correlation with motor function scale at eight months after stroke onset were evaluated. Results: The serial examinations showed that hyperintensity could eventually disappear. Both the ipsilateral ADC and FA values were significantly decreased (p < 0.05) compared to the contralateral side. The ipsilateral FA significantly correlated with motor function scale in both groups (r = 0.875, 0.738; p = 0.004, 0.006 respectively). Conclusions: The hyperintensity on DWI is a transient pathological process of Wallerian degeneration after ischemic stroke, its diffusion characteristics include concurrent significant decrease of ipsilateral ADC and FA. The ipsilateral FA value has the potential to predict neurological motor function outcome in such patients.

  5. White matter hyperintensities and changes in white matter integrity in patients with Alzheimer's disease

    International Nuclear Information System (INIS)

    Wang, Liya; Mao, Hui; Goldstein, Felicia C.; Levey, Allan I.; Lah, James J.; Meltzer, Carolyn C.; Holder, Chad A.

    2011-01-01

    White matter hyperintensities (WMHs) are a risk factor for Alzheimer's disease (AD). This study investigated the relationship between WMHs and white matter changes in AD using diffusion tensor imaging (DTI) and the sensitivity of each DTI index in distinguishing AD with WMHs. Forty-four subjects with WMHs were included. Subjects were classified into three groups based on the Scheltens rating scale: 15 AD patients with mild WMHs, 12 AD patients with severe WMHs, and 17 controls with mild WMHs. Fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (D R ), and axial diffusivity (D A ) were analyzed using the region of interest and tract-based spatial statistics methods. Sensitivity and specificity of DTI indices in distinguishing AD groups from the controls were evaluated. AD patients with mild WMHs exhibited differences from control subjects in most DTI indices in the medial temporal and frontal areas; however, differences in DTI indices from AD patients with mild WMHs and AD patients with severe WMHs were found in the parietal and occipital areas. FA and D R were more sensitive measurements than MD and D A in differentiating AD patients from controls, while MD was a more sensitive measurement in distinguishing AD patients with severe WMHs from those with mild WMHs. WMHs may contribute to the white matter changes in AD brains, specifically in temporal and frontal areas. Changes in parietal and occipital lobes may be related to the severity of WMHs. D R may serve as an imaging marker of myelin deficits associated with AD. (orig.)

  6. MRI Evaluation of Non-Necrotic T2-Hyperintense Foci in Pediatric Diffuse Intrinsic Pontine Glioma.

    Science.gov (United States)

    Clerk-Lamalice, O; Reddick, W E; Li, X; Li, Y; Edwards, A; Glass, J O; Patay, Z

    2016-05-19

    The conventional MR imaging appearance of diffuse intrinsic pontine glioma suggests intralesional histopathologic heterogeneity, and various distinct lesion components, including T2-hypointense foci, have been described. Here we report the prevalence, conventional MR imaging semiology, and advanced MR imaging features of non-necrotic T2-hyperintense foci in diffuse intrinsic pontine glioma. Twenty-five patients with diffuse intrinsic pontine gliomas were included in this study. MR imaging was performed at 3T by using conventional and advanced MR imaging sequences. Perfusion (CBV), vascular permeability (v e , K trans ), and diffusion (ADC) metrics were calculated and used to characterize non-necrotic T2-hyperintense foci in comparison with other lesion components, namely necrotic T2-hyperintense foci, T2-hypointense foci, peritumoral edema, and normal brain stem. Statistical analysis was performed by using Kruskal-Wallis and Wilcoxon rank sum tests. Sixteen non-necrotic T2-hyperintense foci were found in 12 tumors. In these foci, ADC values were significantly higher than those in either T2-hypointense foci (P = .002) or normal parenchyma (P = .0002), and relative CBV values were significantly lower than those in either T2-hypointense (P = .0002) or necrotic T2-hyperintense (P = .006) foci. Volume transfer coefficient values in T2-hyperintense foci were lower than those in T2-hypointense (P = .0005) or necrotic T2-hyperintense (P = .0348) foci. Non-necrotic T2-hyperintense foci are common, distinct lesion components within diffuse intrinsic pontine gliomas. Advanced MR imaging data suggest low cellularity and an early stage of angioneogenesis with leaky vessels resulting in expansion of the extracellular space. Because of the lack of biopsy validation, the underlying histoarchitectural and pathophysiologic changes remain unclear; therefore, these foci may correspond to a poorly understood biologic event in tumor evolution. © 2016 American Society of Neuroradiology.

  7. White Matter Hyperintensity Volume and Cerebral Perfusion in Older Individuals with Hypertension Using Arterial Spin-Labeling

    NARCIS (Netherlands)

    van Dalen, J. W.; Mutsaerts, H. J. M. M.; Nederveen, A. J.; Vrenken, H.; Steenwijk, M. D.; Caan, M. W. A.; Majoie, C. B. L. M.; van Gool, W. A.; Richard, E.

    2016-01-01

    BACKGROUND AND PURPOSE: White matter hyperintensities of presumed vascular origin in elderly patients with hypertension may be part of a general cerebral perfusion deficit, involving not only the white matter hyperintensities but also the surrounding normal-appearing white matter and gray matter. We

  8. White matter magnetic resonance hyperintensities in dementia of the Alzheimer type

    DEFF Research Database (Denmark)

    Waldemar, G; Christiansen, P; Larsson, H B

    1994-01-01

    In a prospective MRI study the presence, appearance, volume, and regional cerebral blood flow (rCBF) correlates of periventricular hyperintensities (PVHs) and deep white matter hyperintensities (DWMHs) were examined in 18 patients with probable Alzheimer's disease and in 10 age matched healthy...... in the Alzheimer's disease group (p ... patients had extensive DWMH lesions in the central white matter. In the group of patients with Alzheimer's disease as a whole, the volume of DWMHs correlated well with rCBF in the hippocampal region ( r = -0.72; p

  9. White matter hyperintensities of presumed vascular origin: a population-based study in rural Ecuador (The Atahualpa Project).

    Science.gov (United States)

    Del Brutto, Oscar H; Mera, Robertino M; Del Brutto, Victor J; Zambrano, Mauricio; Lama, Julio

    2015-04-01

    Cerebral small vessel disease is probably one of the most common pathogenetic mechanisms underlying stroke in Latin America. However, the importance of silent markers of small vessel disease, including white matter hyperintensities of presumed vascular origin, has not been assessed so far. The study aims to evaluate prevalence and correlates of white matter hyperintensities in community-dwelling elders living in Atahualpa (rural Ecuador). Atahualpa residents aged ≥ 60 years were identified during a door-to-door survey and invited to undergo brain magnetic resonance imaging for identification and grading white matter hyperintensities and other markers of small vessel disease. Using multivariate logistic regression models, we evaluated whether white matter hyperintensities is associated with demographics, cardiovascular health status, stroke, cerebral microbleeds, and cortical atrophy, after adjusting for the other variables. Out of 258 enrolled persons (mean age, 70 ± 8 years; 59% women), 172 (67%) had white matter hyperintensities, which were moderate to severe in 63. Analyses showed significant associations of white matter hyperintensities presence and severity with age and cardiovascular health status, as well as with overt and silent strokes, and a trend for association with cerebral microbleeds and cortical atrophy. Prevalence and correlates of white matter hyperintensities in elders living in rural Ecuador is almost comparable with that reported from industrialized nations, reinforcing the concept that the burden of small vessel disease is on the rise in underserved Latin American populations. © 2014 World Stroke Organization.

  10. Cognitive Function and 3-Tesla Magnetic Resonance Imaging Tractography of White Matter Hyperintensities in Elderly Persons

    OpenAIRE

    Reginold, William; Luedke, Angela C.; Tam, Angela; Itorralba, Justine; Fernandez-Ruiz, Juan; Reginold, Jennifer; Islam, Omar; Garcia, Angeles

    2015-01-01

    Background/Aims: This study used 3-Tesla magnetic resonance imaging (MRI) tractography to determine if there was an association between tracts crossing white matter hyperintensities (WMH) and cognitive function in elderly persons. Methods: Brain T2-weighted fluid-attenuated inversion recovery (FLAIR) and diffusion tensor MRI scans were acquired in participants above the age of 60 years. Twenty-six persons had WMH identified on T2 FLAIR scans. They completed a battery of neuropsychological tes...

  11. Thalamic diffusion differences related to cognitive function in white matter lesions.

    Science.gov (United States)

    Fernández-Andújar, Marina; Soriano-Raya, Juan José; Miralbell, Júlia; López-Cancio, Elena; Cáceres, Cynthia; Bargalló, Núria; Barrios, Maite; Arenillas, Juan Francisco; Toran, Pere; Alzamora, Maite; Clemente, Imma; Dávalos, Antoni; Mataró, Maria

    2014-05-01

    Cerebral white matter lesions (WMLs) are related to cognitive deficits, probably due to a disruption of frontal-subcortical circuits. We explored thalamic diffusion differences related to white matter lesions (WMLs) and their association with cognitive function in middle-aged individuals. Ninety-six participants from the Barcelona-AsIA Neuropsychology Study were included. Participants were classified into groups based on low grade and high grade of periventricular hyperintensities (PVHs) and deep white matter hyperintensities (DWMHs). Tract-Based Spatial Statistics was used to study thalamic diffusion differences between groups. Mean fractional anisotropy (FA) values in significant areas were calculated for each subject and correlated with cognitive performance. Participants with high-grade PVHs and DWMHs showed lower FA thalamic values compared to those with low-grade PVHs and DWMHs, respectively. Decreased FA thalamic values in high-grade DWMHs, but not high-grade PVH, were related to lower levels of performance in psychomotor speed, verbal fluency, and visuospatial skills. Thalamic diffusion differences are related to lower cognitive function only in participants with high-grade DWMHs. These results support the hypothesis that fronto-subcortical disruption is associated with cognitive function only in DWMHs. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. White matter hyperintensities and working memory : An explorative study

    NARCIS (Netherlands)

    van Harten, Barbera; Weinstein, Henry C.; Scheltens, Philip; Sergeant, Joseph A.; Scherder, Erik J. A.; Oosterman, J

    2008-01-01

    White matter hyperintensities (WMH) are commonly observed in elderly people and may have the most profound effect on executive functions, including working memory. Surprisingly, the Digit Span backward, a frequently employed working memory task, reveals no association with WMH. In the present study,

  13. Relation between age-related decline in intelligence and cerebral white-matter hyperintensities in healthy octogenarians: a longitudinal study

    DEFF Research Database (Denmark)

    Garde, E; Mortensen, Erik Lykke; Krabbe, K

    2000-01-01

    , but no participant scored more than 75% of maximum for deep white-matter hyperintensities. Neither type was related to the WAIS IQs of the 80-year assessment, but both were significantly associated with decline in performance IQ from age 50 to age 80 years (bivariate correlation coefficients 0.32, p=0.0087, and 0......, and they agreed to further WAIS testing at age 80, and cerebral MRI at age 80-82 (mean age 82.3 years). We scored separately the numbers of periventricular and deep white-matter hyperintensities. FINDINGS: Scores for periventricular hyperintensities in this sample included all possible degrees of severity.......28, p=0.0227, respectively). An analysis based on two WAIS subtests showed that the association between white-matter hyperintensities and cognitive impairment was significant only for cognitive decline in the decade 70-80 years. INTERPRETATION: Both periventricular and deep white-matter hyperintensities...

  14. DEWS (DEep White matter hyperintensity Segmentation framework): A fully automated pipeline for detecting small deep white matter hyperintensities in migraineurs.

    Science.gov (United States)

    Park, Bo-Yong; Lee, Mi Ji; Lee, Seung-Hak; Cha, Jihoon; Chung, Chin-Sang; Kim, Sung Tae; Park, Hyunjin

    2018-01-01

    Migraineurs show an increased load of white matter hyperintensities (WMHs) and more rapid deep WMH progression. Previous methods for WMH segmentation have limited efficacy to detect small deep WMHs. We developed a new fully automated detection pipeline, DEWS (DEep White matter hyperintensity Segmentation framework), for small and superficially-located deep WMHs. A total of 148 non-elderly subjects with migraine were included in this study. The pipeline consists of three components: 1) white matter (WM) extraction, 2) WMH detection, and 3) false positive reduction. In WM extraction, we adjusted the WM mask to re-assign misclassified WMHs back to WM using many sequential low-level image processing steps. In WMH detection, the potential WMH clusters were detected using an intensity based threshold and region growing approach. For false positive reduction, the detected WMH clusters were classified into final WMHs and non-WMHs using the random forest (RF) classifier. Size, texture, and multi-scale deep features were used to train the RF classifier. DEWS successfully detected small deep WMHs with a high positive predictive value (PPV) of 0.98 and true positive rate (TPR) of 0.70 in the training and test sets. Similar performance of PPV (0.96) and TPR (0.68) was attained in the validation set. DEWS showed a superior performance in comparison with other methods. Our proposed pipeline is freely available online to help the research community in quantifying deep WMHs in non-elderly adults.

  15. White matter hyperintensities and normal-appearing white matter integrity in the aging brain.

    Science.gov (United States)

    Maniega, Susana Muñoz; Valdés Hernández, Maria C; Clayden, Jonathan D; Royle, Natalie A; Murray, Catherine; Morris, Zoe; Aribisala, Benjamin S; Gow, Alan J; Starr, John M; Bastin, Mark E; Deary, Ian J; Wardlaw, Joanna M

    2015-02-01

    White matter hyperintensities (WMH) of presumed vascular origin are a common finding in brain magnetic resonance imaging of older individuals and contribute to cognitive and functional decline. It is unknown how WMH form, although white matter degeneration is characterized pathologically by demyelination, axonal loss, and rarefaction, often attributed to ischemia. Changes within normal-appearing white matter (NAWM) in subjects with WMH have also been reported but have not yet been fully characterized. Here, we describe the in vivo imaging signatures of both NAWM and WMH in a large group of community-dwelling older people of similar age using biomarkers derived from magnetic resonance imaging that collectively reflect white matter integrity, myelination, and brain water content. Fractional anisotropy (FA) and magnetization transfer ratio (MTR) were significantly lower, whereas mean diffusivity (MD) and longitudinal relaxation time (T1) were significantly higher, in WMH than NAWM (p curve, 0.982; 95% CI, 0.975-0.989). Furthermore, the level of deterioration of NAWM was strongly associated with the severity of WMH, with MD and T1 increasing and FA and MTR decreasing in NAWM with increasing WMH score, a relationship that was sustained regardless of distance from the WMH. These multimodal imaging data indicate that WMH have reduced structural integrity compared with surrounding NAWM, and MD provides the best discriminator between the 2 tissue classes even within the mild range of WMH severity, whereas FA, MTR, and T1 only start reflecting significant changes in tissue microstructure as WMH become more severe. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  16. White Matter Hyperintensities on MRI in High-Altitude U-2 Pilots

    Science.gov (United States)

    2013-08-19

    SUBJECT TERMS MRI; white matter hyperintensities; hypobaric exposure; neurological decompression sickness 16. SECURITY CLASSIFICATION OF: 17...normal controls and did not increase with age in pilots, suggesting that hypobaric exposure produces white matter damage different from that occurring in...relapse we observed in 3 NDCS pilots after successful hyperbaric treatment (US Navy Treatment Table 6; 100% fraction of inspired oxygen; 2.8 atm absolute

  17. Contrast-based fully automatic segmentation of white matter hyperintensities: method and validation.

    Directory of Open Access Journals (Sweden)

    Thomas Samaille

    Full Text Available White matter hyperintensities (WMH on T2 or FLAIR sequences have been commonly observed on MR images of elderly people. They have been associated with various disorders and have been shown to be a strong risk factor for stroke and dementia. WMH studies usually required visual evaluation of WMH load or time-consuming manual delineation. This paper introduced WHASA (White matter Hyperintensities Automated Segmentation Algorithm, a new method for automatically segmenting WMH from FLAIR and T1 images in multicentre studies. Contrary to previous approaches that were based on intensities, this method relied on contrast: non linear diffusion filtering alternated with watershed segmentation to obtain piecewise constant images with increased contrast between WMH and surroundings tissues. WMH were then selected based on subject dependant automatically computed threshold and anatomical information. WHASA was evaluated on 67 patients from two studies, acquired on six different MRI scanners and displaying a wide range of lesion load. Accuracy of the segmentation was assessed through volume and spatial agreement measures with respect to manual segmentation; an intraclass correlation coefficient (ICC of 0.96 and a mean similarity index (SI of 0.72 were obtained. WHASA was compared to four other approaches: Freesurfer and a thresholding approach as unsupervised methods; k-nearest neighbours (kNN and support vector machines (SVM as supervised ones. For these latter, influence of the training set was also investigated. WHASA clearly outperformed both unsupervised methods, while performing at least as good as supervised approaches (ICC range: 0.87-0.91 for kNN; 0.89-0.94 for SVM. Mean SI: 0.63-0.71 for kNN, 0.67-0.72 for SVM, and did not need any training set.

  18. Presence and progression of white matter hyperintensities and cognition A meta-analysis

    NARCIS (Netherlands)

    Kloppenborg, Raoul P.; Nederkoorn, Paul J.; Geerlings, Mirjam I.; van den Berg, Esther

    2014-01-01

    Objective: We aimed to quantify the effects of white matter hyperintensities (WMHs) on specific cognitive functions with particular attention to WMH progression and localization. Methods: PubMed (January 1990-July 2013) and bibliographies from included articles were used. Studies that were included

  19. Persistent lesion hyperintensity on brain diffusion-weighted MRI is an early sign of intravascular lymphoma.

    Science.gov (United States)

    Kageyama, Takashi; Yamanaka, Haruo; Nakamura, Fumihiko; Suenaga, Toshihiko

    2017-06-08

    A 63-year-old man presented with right-sided hemianopia and unsteady gait. Brain MRI revealed multiple hyperintense infarct-like lesions on diffusion-weighted images (DWI). Hyperintensity persisted in some of these lesions even after 6 weeks, although his symptoms were ameliorated then. The patient developed episodic dizziness and a transient event of apraxia at 18 weeks after the first episode. Brain MRI revealed additional hyperintense lesions on DWI, which persisted even after 7 weeks. Eventually, the patient manifested cauda equina syndrome 39 weeks after the first episode. Brain MRI showed the presence of new lesions in addition to the persistent hyperintense lesions on DWI over 21 weeks in the right frontal lobe. Based on laboratory findings and the pathological assessment of bone marrow and random skin biopsies, the patient was diagnosed with intravascular lymphoma (IVL). Persistent hyperintense lesions on DWI of brain MRI may precede the clinical exacerbation of IVL. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  20. Clinical significance of white matter hyperintensities in MRI in senile dementia of the Alzheimer type

    International Nuclear Information System (INIS)

    Takita, Masashi

    1996-01-01

    To elucidate clinical significance of white matter hyperintensities (WMH) in MRI, fifty patients with senile dementia of the Alzheimer type (SDAT) and twenty normal controls were studied. Twenty nine patients with SDAT (58.0%) had periventricular hyperintensities (PVH) and twenty three patients with SDAT (46.0%) had deep white matter hyperintensities (DWMH). Eight controls (40.0%) had PVH and ten controls (50.0%) had DWMH. There were no significant differences in frequency of WMH between patients with SDAT and normal controls. Past history of hypertension was more frequent in patients with PVH or DWMH than in patients without them. Serum cholesterol level was higher in patients with DWMH than in patients without them. However there were no significant differences in the other clinical features between patients with WMH and patients without them. The results of present study suggest that DWMH in patients with SDAT is associated with cerebrovascular risk factors such as hypertension and hyperlipidemia. (author)

  1. Normal variation of focal T2 Hyperintensities in anterior parietal periventricular white matter: Another 'Terminal Zones of Myelination'

    International Nuclear Information System (INIS)

    Park, Jong Oag; Woo, Je Ho; Ki, Tae Sung; Lee, Jong Hwa; Chung, Jin Woo; Lee, Don Young

    1994-01-01

    It has been known that there are several areas of T2 hyperintensity in normal white matter of brain, such as terminal zones of myelination, ependymitis granularis, ones of posterior internal capsule, and perivascular space. The aim of our study is to demonstrate another region of T2 hyperintensities in normal pediatric age group. We have studied brain MR for 10 normal volunteers and 35 patients without having intracranial lesions in pediatric age group(3-19 years). In 5 among 45 cases, focal T2 hyperintensities were seen in the parietal periventricular white matter beneath the postcentral gyri. They were noted as poorly defined, 5-10 mm sized areas of increased signal intensities on T2-weighted axial images. They were also characterized by bilateral, posteromedially oriented, short band-like or oval areas. Interestingly, they were directly continuous with the T2 hyperintensity of posterior internal capsule. In spite of the relatively highly frequency in the pediatric population as in our study, this finding has not been reported in the asymptomatic adults. The results show that the bilateral anterior parietal hyperintense areas may be another terminal zones of delayed myelination affecting the parietopontine tract. They should be differentiated from pathologic T2 hyperintensities by their characteristic findings

  2. Frontal white matter hyperintensities, clasmatodendrosis and gliovascular abnormalities in ageing and post-stroke dementia.

    Science.gov (United States)

    Chen, Aiqing; Akinyemi, Rufus O; Hase, Yoshiki; Firbank, Michael J; Ndung'u, Michael N; Foster, Vincent; Craggs, Lucy J L; Washida, Kazuo; Okamoto, Yoko; Thomas, Alan J; Polvikoski, Tuomo M; Allan, Louise M; Oakley, Arthur E; O'Brien, John T; Horsburgh, Karen; Ihara, Masafumi; Kalaria, Raj N

    2016-01-01

    White matter hyperintensities as seen on brain T2-weighted magnetic resonance imaging are associated with varying degrees of cognitive dysfunction in stroke, cerebral small vessel disease and dementia. The pathophysiological mechanisms within the white matter accounting for cognitive dysfunction remain unclear. With the hypothesis that gliovascular interactions are impaired in subjects with high burdens of white matter hyperintensities, we performed clinicopathological studies in post-stroke survivors, who had exhibited greater frontal white matter hyperintensities volumes that predicted shorter time to dementia onset. Histopathological methods were used to identify substrates in the white matter that would distinguish post-stroke demented from post-stroke non-demented subjects. We focused on the reactive cell marker glial fibrillary acidic protein (GFAP) to study the incidence and location of clasmatodendrosis, a morphological attribute of irreversibly injured astrocytes. In contrast to normal appearing GFAP+ astrocytes, clasmatodendrocytes were swollen and had vacuolated cell bodies. Other markers such as aldehyde dehydrogenase 1 family, member L1 (ALDH1L1) showed cytoplasmic disintegration of the astrocytes. Total GFAP+ cells in both the frontal and temporal white matter were not greater in post-stroke demented versus post-stroke non-demented subjects. However, the percentage of clasmatodendrocytes was increased by >2-fold in subjects with post-stroke demented compared to post-stroke non-demented subjects (P = 0.026) and by 11-fold in older controls versus young controls (P < 0.023) in the frontal white matter. High ratios of clasmotodendrocytes to total astrocytes in the frontal white matter were consistent with lower Mini-Mental State Examination and the revised Cambridge Cognition Examination scores in post-stroke demented subjects. Double immunofluorescent staining showed aberrant co-localization of aquaporin 4 (AQP4) in retracted GFAP+ astrocytes with

  3. Genome-wide meta-analysis of cerebral white matter hyperintensities in patients with stroke

    NARCIS (Netherlands)

    Traylor, M.; Zhang, C.R.; Adib-Samii, P.; Devan, W.J.; Parsons, O.E.; Lanfranconi, S.; Gregory, S.; Cloonan, L.; Falcone, G.J.; Radmanesh, F.; Fitzpatrick, K.; Kanakis, A.; Barrick, T.R.; Moynihan, B.; Lewis, C.M.; Boncoraglio, G.B.; Lemmens, R.; Thijs, V.; Sudlow, C.; Wardlaw, J.; Rothwell, P.M.; Meschia, J.F.; Worrall, B.B.; Levi, C.; Bevan, S.; Furie, K.L.; Dichgans, M.; Rosand, J.; Markus, H.S.; Rost, N.; Klijn, C.J.M.; et al.,

    2016-01-01

    OBJECTIVE: For 3,670 stroke patients from the United Kingdom, United States, Australia, Belgium, and Italy, we performed a genome-wide meta-analysis of white matter hyperintensity volumes (WMHV) on data imputed to the 1000 Genomes reference dataset to provide insights into disease mechanisms.

  4. Status epilepticus in the elderly: Prognostic implications of rhythmic and periodic patterns in electroencephalography and hyperintensities on diffusion-weighted imaging.

    Science.gov (United States)

    Yoshimura, Hajime; Matsumoto, Riki; Ueda, Hiroyuki; Ariyoshi, Koichi; Kawamoto, Michi; Ishii, Junko; Ikeda, Akio; Takahashi, Ryosuke; Kohara, Nobuo

    2016-11-15

    To delineate the clinical characteristics and functional outcome of status epilepticus (SE) in elderly people, and elucidate prognostic implications of SE-associated rhythmic and periodic patterns (RPPs) in electroencephalography and hyperintensities on diffusion-weighted imaging. We retrospectively investigated 107 consecutive patients with SE aged≥65years in a comprehensive community hospital. RPPs were classified using the 2012 American Clinical Neurophysiology Society's Standardized Critical Care EEG Terminology. Poor outcome was defined as an increase in modified Rankin Scale (mRS) score at discharge compared with that at baseline, including death. Median age of patients was 80.0years. Median mRS score at baseline was 3. Thirty-four patients (31.8%) had a previous diagnosis of epilepsy. Cerebrovascular disease and dementia were major etiologies. Poor outcome occurred in 41 (38.3%). In electroencephalography, periodic discharges (PDs) were present in 21.0% (22/105), rhythmic delta activity (RDA) in 10.5% (11/105), and conventional seizure patterns in 9.5% (10/105). Diffusion-weighted hyperintensities associated with SE were observed in 28.0% (26/93). With univariate analysis, poor outcome was significantly associated with no previous diagnosis of epilepsy, etiology, refractory SE, specific electroencephalographic patterns (PDs and conventional seizure patterns, but not RDA), and diffusion-weighted hyperintensities. With multivariate logistic regression analysis, diffusion-weighted hyperintensities (OR 6.13 [95% CI 1.72-21.9]) and refractory SE (OR 5.36 [95% CI 1.28-22.4]) were independently associated with poor outcome. SE often occurred as the first seizure in already disabled elderly people, further worsening their functional disabilities. Diffusion-weighted hyperintensities and refractory SE, but not RPPs in electroencephalography, were independent functional prognostic factors. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. White Matter Hyperintensities and Cognitive Impairment During Electroconvulsive Therapy in Severely Depressed Elderly Patients

    NARCIS (Netherlands)

    Oudega, M.L.; van Exel, E.; Wattjes, M.P.; Comijs, H.C.; Scheltens, P.; Barkhof, F.; Eikelenboom, P.; Craen, A.J.M.; Beekman, A.T.F.; Stek, M.L.

    2014-01-01

    Objective: Transient cognitive impairment during electroconvulsive therapy (ECT) can be a reason to discontinue ECT in depressed elderly patients. We hypothesized that both white matter hyperintensities and medial temporal lobe atrophy contribute to transient cognitive impairment during ECT.

  6. Cognitive Function and 3-Tesla Magnetic Resonance Imaging Tractography of White Matter Hyperintensities in Elderly Persons.

    Science.gov (United States)

    Reginold, William; Luedke, Angela C; Tam, Angela; Itorralba, Justine; Fernandez-Ruiz, Juan; Reginold, Jennifer; Islam, Omar; Garcia, Angeles

    2015-01-01

    This study used 3-Tesla magnetic resonance imaging (MRI) tractography to determine if there was an association between tracts crossing white matter hyperintensities (WMH) and cognitive function in elderly persons. Brain T2-weighted fluid-attenuated inversion recovery (FLAIR) and diffusion tensor MRI scans were acquired in participants above the age of 60 years. Twenty-six persons had WMH identified on T2 FLAIR scans. They completed a battery of neuropsychological tests and were classified as normal controls (n = 15) or with Alzheimer's dementia (n = 11). Tractography was generated by the Fiber Assignment by Continuous Tracking method. All tracts that crossed WMH were segmented. The average fractional anisotropy and average mean diffusivity of these tracts were quantified. We studied the association between cognitive test scores with the average mean diffusivity and average fractional anisotropy of tracts while controlling for age, total WMH volume and diagnosis. An increased mean diffusivity of tracts crossing WMH was associated with worse performance on the Wechsler Memory Scale-III Longest Span Forward (p = 0.02). There was no association between the fractional anisotropy of tracts and performance on cognitive testing. The mean diffusivity of tracts crossing WMH measured by tractography is a novel correlate of performance on the Wechsler Memory Scale-III Longest Span Forward in elderly persons.

  7. Relation between age-related decline in intelligence and cerebral white-matter hyperintensities in healthy octogenarians: a longitudinal study

    DEFF Research Database (Denmark)

    Garde, E; Mortensen, E L; Krabbe, K

    2000-01-01

    BACKGROUND: White-matter hyperintensities are commonly found on magnetic resonance imaging (MRI) of elderly people with or without dementia. Studies of the relation between severity of white-matter hyperintensities and cognitive impairment have had conflicting results. We undertook a longitudinal...... study of age-related decline in intellectual function and MRI at age 80 years. METHODS: From a cohort of 698 people born in 1914 and living in seven municipalities in Denmark, 68 healthy non-demented individuals had been tested with the Wechsler adult intelligence scale (WAIS) at ages 50, 60, and 70...

  8. Clinico-radiological features of subarachnoid hyperintensity on diffusion-weighted images in patients with meningitis

    International Nuclear Information System (INIS)

    Kawaguchi, T.; Sakurai, K.; Hara, M.; Muto, M.; Nakagawa, M.; Tohyama, J.; Oguri, T.; Mitake, S.; Maeda, M.; Matsukawa, N.; Ojika, K.; Shibamoto, Y.

    2012-01-01

    Aim: To investigate the clinical and radiological features of meningitis with subarachnoid diffusion-weighted imaging (DWI) hyperintensity. Materials and methods: The clinical features, laboratory data, and radiological findings, including the number and distribution of subarachnoid DWI hyperintense lesions and other radiological abnormalities, of 18 patients seen at five institutions were evaluated. Results: The patients consisted of eight males and 10 females, whose ages ranged from 4 months to 82 years (median 65 years). Causative organisms were bacteria in 15 patients, including Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus agalactiae, Staphylococcus aureus, Klebsiella pneumoniae, and Listeria monocytogenes. The remaining three were fungal meningitis caused by Cryptococcus neoformans. Subarachnoid DWI hyperintense lesions were multiple in 16 of the 18 cases (89%) and predominantly distributed around the frontal lobe in 16 of the 18 cases (89%). In addition to subarachnoid abnormality, subdural empyema, cerebral infarction, and intraventricular empyema were found in 50, 39, and 39%, respectively. Compared with paediatric patients, adult patients with bacterial meningitis tended to have poor prognoses (7/10 versus 1/5; p = 0.1). Conclusion: Both bacterial and fungal meningitis could cause subarachnoid hyperintensity on DWI, predominantly around the frontal lobe. This finding is often associated with poor prognosis in adult bacterial meningitis.

  9. Clinico-radiological features of subarachnoid hyperintensity on diffusion-weighted images in patients with meningitis

    Energy Technology Data Exchange (ETDEWEB)

    Kawaguchi, T., E-mail: madarafuebuki@yahoo.co.jp [Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya (Japan); Sakurai, K.; Hara, M. [Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya (Japan); Muto, M. [Department of Radiology, Okazaki City Hospital, Okazaki, Aichi (Japan); Nakagawa, M. [Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya (Japan); Tohyama, J. [Department of Radiology, Toyota-kai Medical Corporation Kariya Toyota General Hospital, Kariya, Aichi (Japan); Oguri, T. [Department of Neurology and Neuroscience, Nagoya City University Graduate School of Medical Sciences, Nagoya (Japan); Mitake, S. [Department of Neurology, Tosei General Hospital, Seto-shi, Aichi (Japan); Maeda, M. [Department of Radiology, Mie University School of Medicine, Tsu, Mie (Japan); Matsukawa, N.; Ojika, K. [Department of Neurology and Neuroscience, Nagoya City University Graduate School of Medical Sciences, Nagoya (Japan); Shibamoto, Y. [Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya (Japan)

    2012-04-15

    Aim: To investigate the clinical and radiological features of meningitis with subarachnoid diffusion-weighted imaging (DWI) hyperintensity. Materials and methods: The clinical features, laboratory data, and radiological findings, including the number and distribution of subarachnoid DWI hyperintense lesions and other radiological abnormalities, of 18 patients seen at five institutions were evaluated. Results: The patients consisted of eight males and 10 females, whose ages ranged from 4 months to 82 years (median 65 years). Causative organisms were bacteria in 15 patients, including Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus agalactiae, Staphylococcus aureus, Klebsiella pneumoniae, and Listeria monocytogenes. The remaining three were fungal meningitis caused by Cryptococcus neoformans. Subarachnoid DWI hyperintense lesions were multiple in 16 of the 18 cases (89%) and predominantly distributed around the frontal lobe in 16 of the 18 cases (89%). In addition to subarachnoid abnormality, subdural empyema, cerebral infarction, and intraventricular empyema were found in 50, 39, and 39%, respectively. Compared with paediatric patients, adult patients with bacterial meningitis tended to have poor prognoses (7/10 versus 1/5; p = 0.1). Conclusion: Both bacterial and fungal meningitis could cause subarachnoid hyperintensity on DWI, predominantly around the frontal lobe. This finding is often associated with poor prognosis in adult bacterial meningitis.

  10. White matter hyperintensities are seen only in GRN mutation carriers in the GENFI cohort

    NARCIS (Netherlands)

    Sudre, C.H. (Carole H.); M. Bocchetta (Martina); D.M. Cash (David M); D.L. Thomas (David L); Woollacott, I. (Ione); Dick, K.M. (Katrina M.); J.C. van Swieten (John); B. Borroni (Barbara); D. Galimberti (Daniela); M. Masellis (Mario); M.C. Tartaglia (Maria Carmela); J.B. Rowe (James); M.J. Graff (Maud J.L.); F. Tagliavini (Fabrizio); G.B. Frisoni (Giovanni B.); R. Laforce (Robert); E. Finger (Elizabeth); A. De Mendonça (Alexandre); S. Sorbi (Sandro); S. Ourselin (Sebastien); M.J. Cardoso (Manuel Jorge); J.D. Rohrer (Jonathan D)

    2017-01-01

    textabstractGenetic frontotemporal dementia is most commonly caused by mutations in the progranulin (GRN), microtubule-associated protein tau (MAPT) and chromosome 9 open reading frame 72 (C9orf72) genes. Previous small studies have reported the presence of cerebral white matter hyperintensities

  11. Risk factor analysis of cerebral white matter hyperintensities in children with sickle cell disease

    NARCIS (Netherlands)

    van der Land, Veronica; Mutsaerts, Henri J. M. M.; Engelen, Marc; Heijboer, Harriët; Roest, Mark; Hollestelle, Martine J.; Kuijpers, Taco W.; Nederkoorn, Paul J.; Cnossen, Marjon H.; Majoie, Charles B. L. M.; Nederveen, Aart J.; Fijnvandraat, Karin

    2016-01-01

    Sickle cell disease (SCD) is complicated by silent cerebral infarcts, visible as white matter hyperintensities (WMHs) on magnetic resonance imaging (MRI). Both local vaso-occlusion, elicited by endothelial dysfunction, and insufficiency of cerebral blood flow (CBF) have been proposed to be involved

  12. Exploring DeepMedic for the purpose of segmenting white matter hyperintensity lesions

    Science.gov (United States)

    Lippert, Fiona; Cheng, Bastian; Golsari, Amir; Weiler, Florian; Gregori, Johannes; Thomalla, Götz; Klein, Jan

    2018-02-01

    DeepMedic, an open source software library based on a multi-channel multi-resolution 3D convolutional neural network, has recently been made publicly available for brain lesion segmentations. It has already been shown that segmentation tasks on MRI data of patients having traumatic brain injuries, brain tumors, and ischemic stroke lesions can be performed very well. In this paper we describe how it can efficiently be used for the purpose of detecting and segmenting white matter hyperintensity lesions. We examined if it can be applied to single-channel routine 2D FLAIR data. For evaluation, we annotated 197 datasets with different numbers and sizes of white matter hyperintensity lesions. Our experiments have shown that substantial results with respect to the segmentation quality can be achieved. Compared to the original parametrization of the DeepMedic neural network, the timings for training can be drastically reduced if adjusting corresponding training parameters, while at the same time the Dice coefficients remain nearly unchanged. This enables for performing a whole training process within a single day utilizing a NVIDIA GeForce GTX 580 graphics board which makes this library also very interesting for research purposes on low-end GPU hardware.

  13. Diffusion-Weighted MR Imaging of Unusual White Matter Lesion in a Patient with Menkes Disease

    International Nuclear Information System (INIS)

    Lee, Eun Shin; Ryoo, Jae Wook; Choi, Dae Seob; Cho, Jae Min; Kwon, Soo Hyun; Shin, Hee Suk

    2007-01-01

    We report here on the diffusion-weighted imaging of unusual white matter lesions in a case of Menkes disease. On the initial MR imaging, the white matter lesions were localized in the deep periventricular white matter in the absence of diffuse cortical atrophy. The lesion showed diffuse high signal on the diffusion weighted images and diffuse progression and persistent hyperintensity on the follow up imaging. Our case suggests that the white matter lesion may precede diffuse cortical atrophy in a patient with Menkes disease. Menkes disease is an X-linked disorder that's caused by impaired intracellular transport of copper. We describe here the DWI findings of unusual and progressive white matter lesions in a case of Menkes disease. Menkes disease is an X-linked recessive disorder, and it is due to an inborn error of copper metabolism. The cause of Menkes disease has been isolated to a genetic defect in copper-transporting adenosine triphosphatase, and this results in low levels of intracellular copper. It is characterized clinically by failure to thrive, retarded mental and motor development, clonic seizure and peculiarly coarse, sparse and colorless scalp hair. These clinical findings can be explained by a dysfunction of the copper-dependent enzymes

  14. Cognitive Function and 3-Tesla Magnetic Resonance Imaging Tractography of White Matter Hyperintensities in Elderly Persons

    Directory of Open Access Journals (Sweden)

    William Reginold

    2015-10-01

    Full Text Available Background/Aims: This study used 3-Tesla magnetic resonance imaging (MRI tractography to determine if there was an association between tracts crossing white matter hyperintensities (WMH and cognitive function in elderly persons. Methods: Brain T2-weighted fluid-attenuated inversion recovery (FLAIR and diffusion tensor MRI scans were acquired in participants above the age of 60 years. Twenty-six persons had WMH identified on T2 FLAIR scans. They completed a battery of neuropsychological tests and were classified as normal controls (n = 15 or with Alzheimer's dementia (n = 11. Tractography was generated by the Fiber Assignment by Continuous Tracking method. All tracts that crossed WMH were segmented. The average fractional anisotropy and average mean diffusivity of these tracts were quantified. We studied the association between cognitive test scores with the average mean diffusivity and average fractional anisotropy of tracts while controlling for age, total WMH volume and diagnosis. Results: An increased mean diffusivity of tracts crossing WMH was associated with worse performance on the Wechsler Memory Scale-III Longest Span Forward (p = 0.02. There was no association between the fractional anisotropy of tracts and performance on cognitive testing. Conclusion: The mean diffusivity of tracts crossing WMH measured by tractography is a novel correlate of performance on the Wechsler Memory Scale-III Longest Span Forward in elderly persons.

  15. Periventricular hyperintensity in children with hydrocephalus

    International Nuclear Information System (INIS)

    Akbari, S.H.A.; Ragan, Dustin K.; Limbrick, David D.; McKinstry, Robert C.; Shimony, Joshua S.; Altaye, Mekibib; Yuan, Weihong; Holland, Scott K.; Mangano, Francesco T.

    2015-01-01

    Magnetic resonance images of children with hydrocephalus often include a rim of hyperintensity in the periventricular white matter (halo). The purpose of this study was to decide between the hypothesis that the halo is caused by cerebrospinal fluid (CSF) flow during the cardiac cycle, and the alternate hypothesis that the halo is caused by anatomical changes (stretching and compression of white matter). Participants were selected from a multicenter imaging study of pediatric hydrocephalus. We compared 19 children with hydrocephalus to a group of 52 controls. We quantified ventricle enlargement using the frontal-occipital horn ratio. We conducted qualitative and quantitative analysis of diffusion tensor imaging in the corpus callosum and posterior limb of the internal capsule. Parameters included the fractional anisotropy (FA), mean diffusivity, axial diffusivity and radial diffusivity. The halo was seen in 16 of the 19 children with hydrocephalus but not in the controls. The corpus callosum of the hydrocephalus group demonstrated FA values that were significantly decreased from those in the control group (P = 4 . 10 -6 ), and highly significant increases were seen in the mean diffusivity and radial diffusivity in the hydrocephalus group. In the posterior limb of the internal capsule the FA values of the hydrocephalus group were higher than those for the control group (P = 0.002), and higher values in the hydrocephalus group were also noted in the axial diffusivity. We noted correlations between the diffusion parameters and the frontal-occipital horn ratio. Our results strongly support the hypothesis that the halo finding in hydrocephalus is caused by structural changes rather than pulsatile CSF flow. (orig.)

  16. White matter hyperintensities and prepulse inhibition in a mixed elderly population

    DEFF Research Database (Denmark)

    Salem, Lise C; Hejl, Anne-Mette; Garde, Ellen

    2011-01-01

    Prepulse inhibition (PPI) of the startle response, a measure for sensorimotor gating, exhibits a relatively high inter-individual variability in elderly subjects. The aim of this study was to investigate whether white matter hyperintensities (WMH), frequently identified on cranial magnetic...... rated visually on craniel MRI FLAIR images using the Fazekas scale. WMH were identified in 70% of all subjects. The latency to peak of the startle response increased significantly with increasing WMH load, whereas the inhibition of the startle response (PPI) was neither significantly related...

  17. Occipital deep white matter hyperintensity as seen by MRI, 1

    International Nuclear Information System (INIS)

    Miyazaki, Masahito; Hashimoto, Toshiaki; Tayama, Masanobu; Kuroda, Yasuhiro

    1992-01-01

    Magnetic resonance imaging was performed in 270 patients with various neurologic complaints (1-15Y) with a 0.5 tesla superconducting imaging system using a field echo T1-weighted sequence and spin echo T2-weighted and PD-weighted sequences. Twenty-seven of them had deep white matter hyperintensity (DWMH) in the occipital lobe on T2-weighted images. The frequency of mild DWMH differed in different age groups, suggesting that mild DWMH may result from delayed myelination in the central nervous system. However, the frequency of severe DWMH, which was revealed as isointense relative to cerebrospinal fluid, did not differ in different age groups and it was significantly more common in severely retarded patients. Classification of DWMH based on the signal intensity is valuable to distinguish white matter abnormalities in the occipital lobe from delayed myelination in the same site. (author)

  18. Periventricular hyperintensity in children with hydrocephalus

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, S.H.A.; Ragan, Dustin K. [St. Louis Children' s Hospital, Washington University School of Medicine, Department of Neurological Surgery, St. Louis, MO (United States); Limbrick, David D. [St. Louis Children' s Hospital, Washington University School of Medicine, Department of Neurological Surgery, St. Louis, MO (United States); McKinstry, Robert C.; Shimony, Joshua S. [St. Louis Children' s Hospital, Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Altaye, Mekibib [Cincinnati Children' s Hospital, Division of Biostatistics and Epidemiology, Cincinnati, OH (United States); Yuan, Weihong; Holland, Scott K. [Cincinnati Children' s Hospital, Department of Pediatric Radiology, Cincinnati, OH (United States); Mangano, Francesco T. [Cincinnati Children' s Hospital, Department of Pediatric Neurological Surgery, Cincinnati, OH (United States)

    2015-08-15

    Magnetic resonance images of children with hydrocephalus often include a rim of hyperintensity in the periventricular white matter (halo). The purpose of this study was to decide between the hypothesis that the halo is caused by cerebrospinal fluid (CSF) flow during the cardiac cycle, and the alternate hypothesis that the halo is caused by anatomical changes (stretching and compression of white matter). Participants were selected from a multicenter imaging study of pediatric hydrocephalus. We compared 19 children with hydrocephalus to a group of 52 controls. We quantified ventricle enlargement using the frontal-occipital horn ratio. We conducted qualitative and quantitative analysis of diffusion tensor imaging in the corpus callosum and posterior limb of the internal capsule. Parameters included the fractional anisotropy (FA), mean diffusivity, axial diffusivity and radial diffusivity. The halo was seen in 16 of the 19 children with hydrocephalus but not in the controls. The corpus callosum of the hydrocephalus group demonstrated FA values that were significantly decreased from those in the control group (P = 4 . 10{sup -6}), and highly significant increases were seen in the mean diffusivity and radial diffusivity in the hydrocephalus group. In the posterior limb of the internal capsule the FA values of the hydrocephalus group were higher than those for the control group (P = 0.002), and higher values in the hydrocephalus group were also noted in the axial diffusivity. We noted correlations between the diffusion parameters and the frontal-occipital horn ratio. Our results strongly support the hypothesis that the halo finding in hydrocephalus is caused by structural changes rather than pulsatile CSF flow. (orig.)

  19. Deletion/insertion polymorphism of the angiotensin-converting enzyme gene and white matter hyperintensities in dementia: A pilot study.

    NARCIS (Netherlands)

    Purandare, N.; Oude Voshaar, R.C.; Davidson, Y.; Gibbons, L.; Hardicre, J.; Byrne, J.; McCollum, C.N.; Jackson, A.; Burns, A.; Mann, D.M.

    2006-01-01

    OBJECTIVES: To examine the association between the angiotensin-converting enzyme (ACE) deletion/insertion (D/I) polymorphism and white matter hyperintensities (WMHs) in patients with dementia. DESIGN: Observational pilot study with adjustment for potential confounders using analysis of covariance.

  20. Diffusion-weighted MRI of maple syrup urine disease encephalopathy

    Energy Technology Data Exchange (ETDEWEB)

    Cavalleri, F.; Mavilla, L. [Servizio di Neuroradiologia, Azienda Ospedaliera Policlinico, Modena (Italy); Berardi, A.; Ferrari, F. [Servizio di Neonatologia, Azienda Ospedaliera Policlinico, Modena (Italy); Burlina, A.B. [Dipartimento di Pediatria, Azienda Ospedaliera, Universita di Padova, Padua (Italy)

    2002-06-01

    We report the case of a newborn child with maple syrup urine disease (MSUD), diagnosed at 10 days of life. Diffusion-weighted echoplanar MRI showed marked hyperintensity of the cerebellar white matter, the brainstem, the cerebral peduncles, the thalami, the dorsal limb of the internal capsule and the centrum semiovale, while conventional dual-echo sequence evidenced only a weak diffuse T2 hyperintensity in the cerebellar white matter and in the dorsal brainstem. The apparent diffusion coefficient (ADC) of these regions was markedly (>80%) decreased. Therefore, in agreement with current hypotheses on MSUD pathogenesis, MSUD oedema proves to be a cytotoxic oedema. Diffusion-weighted MRI may be a valuable tool, more sensitive than conventional spin-echo techniques, to assess the extent and progression of cytotoxicity in MSUD, as well as the effectiveness of the therapeutic interventions. (orig.)

  1. Diffusion-weighted MRI of maple syrup urine disease encephalopathy

    International Nuclear Information System (INIS)

    Cavalleri, F.; Mavilla, L.; Berardi, A.; Ferrari, F.; Burlina, A.B.

    2002-01-01

    We report the case of a newborn child with maple syrup urine disease (MSUD), diagnosed at 10 days of life. Diffusion-weighted echoplanar MRI showed marked hyperintensity of the cerebellar white matter, the brainstem, the cerebral peduncles, the thalami, the dorsal limb of the internal capsule and the centrum semiovale, while conventional dual-echo sequence evidenced only a weak diffuse T2 hyperintensity in the cerebellar white matter and in the dorsal brainstem. The apparent diffusion coefficient (ADC) of these regions was markedly (>80%) decreased. Therefore, in agreement with current hypotheses on MSUD pathogenesis, MSUD oedema proves to be a cytotoxic oedema. Diffusion-weighted MRI may be a valuable tool, more sensitive than conventional spin-echo techniques, to assess the extent and progression of cytotoxicity in MSUD, as well as the effectiveness of the therapeutic interventions. (orig.)

  2. A voxel-based diffusion tensor imaging study of white matter in bipolar disorder.

    Science.gov (United States)

    Mahon, Katie; Wu, Jinghui; Malhotra, Anil K; Burdick, Katherine E; DeRosse, Pamela; Ardekani, Babak A; Szeszko, Philip R

    2009-05-01

    There is evidence from post-mortem and magnetic resonance imaging studies that hyperintensities, oligodendroglial abnormalities, and gross white matter volumetric alterations are involved in the pathophysiology of bipolar disorder. There is also functional imaging evidence for a defect in frontal cortico-subcortical pathways in bipolar disorder, but the white matter comprising these pathways has not been well investigated. Few studies have investigated white matter integrity in patients with bipolar disorder compared to healthy volunteers and the majority of studies have used manual region-of-interest approaches. In this study, we compared fractional anisotropy (FA) values between 30 patients with bipolar disorder and 38 healthy volunteers in the brain white matter using a voxelwise analysis following intersubject registration to Talairach space. Compared to healthy volunteers, patients demonstrated significantly (p or =50) higher FA within the right and left frontal white matter and lower FA within the left cerebellar white matter. Examination of individual eigenvalues indicated that group differences in both axial diffusivity and radial diffusivity contributed to abnormal FA within these regions. Tractography was performed in template space on averaged diffusion tensor imaging data from all individuals. Extraction of bundles passing through the clusters that differed significantly between groups suggested that white matter abnormalities along the pontine crossing tract, corticospinal/corticopontine tracts, and thalamic radiation fibers may be involved in the pathogenesis of bipolar disorder. Our findings are consistent with models of bipolar disorder that implicate dysregulation of cortico-subcortical and cerebellar regions in the disorder and may have relevance for phenomenology.

  3. Diffusion changes predict cognitive and functional outcome

    DEFF Research Database (Denmark)

    Jokinen, Hanna; Schmidt, Reinhold; Ropele, Stefan

    2013-01-01

    A study was undertaken to determine whether diffusion-weighted imaging (DWI) abnormalities in normal-appearing brain tissue (NABT) and in white matter hyperintensities (WMH) predict longitudinal cognitive decline and disability in older individuals independently of the concomitant magnetic...

  4. A radiological study of cerebral white matter lesions in patients with dementia using diffusion-weighted MR imaging

    International Nuclear Information System (INIS)

    Shindo, Hiroaki; Hanyu, Haruo; Kakizaki, Dai; Abe, Kimihiko; Takasaki, Masaru

    1999-01-01

    We investigated the changes in water diffusion in the cerebral white matter and the corpus callosum in 12 patients with Binswanger's disease (BD), and 19 patients with Alzheimer's Disease (AD), including 12 without (AD-) and 7 with periventricular hyperintensity (PVH) lesions (AD+), using diffusion-weighted magnetic resonance imaging (MRI). Apparent diffusion coefficients (ADCs) in the anterior and posterior white matter were significantly higher in patients with BD and AD than in 12 age-matched controls. The ADCs were significantly higher in AD (+) than in AD (-) patients. Anisotropic ratios (ARs), defined as diffusion restricted perpendicular to the direction of the nerve fibers, were significantly higher in BD and AD (+) patients, and even in AD (-) patients, than in the controls. ARs in the anterior white matter were significantly higher in BD than in AD (+), while in the posterior white matter the ratios were significantly higher in AD (+) rather than BD patients. The ADCs and ARs in the genu of the corpus callosum were significantly higher in patients with BD and AD (+) compared to the control subjects, while ADCs and ARs in the splenium were significantly higher in patients with AD (+) and AD (-) than in those with BD. These results suggest that mild myelin loss occurs in AD patients even in apparently normal white matter and in the splenium of the corpus callosum. A definite loss of myelin and axons, including incomplete infarction, occurs preferentially in anterior white matter in BD, while in posterior white matter in AD (+), as seen on T2-weighted images as PVH. Studies with diffusion-weighted MRI may allow the characterization of different pathological processes and enable the demonstration of underlying white matter lesion in patients with dementia that cannot be visualized by conventional MRI. (author)

  5. Impact of white matter hyperintensities scoring method on correlations with clinical data: the LADIS study

    DEFF Research Database (Denmark)

    van Straaten, EC; Fazekas, F; Rostrup, Egill

    2006-01-01

    BACKGROUND AND PURPOSE: White matter hyperintensities (WMH) are associated with decline in cognition, gait, mood, and urinary continence. Associations may depend on the method used for measuring WMH. We investigated the ability of different WMH scoring methods to detect differences in WMH load...... between groups with and without symptoms. METHODS: We used data of 618 independently living elderly with WMH collected in the Leukoaraiosis And DISability (LADIS) study. Subjects with and without symptoms of depression, gait disturbances, urinary incontinence, and memory decline were compared with respect...... to WMH load measured qualitatively using 3 widely used visual rating scales (Fazekas, Scheltens, and Age-Related White Matter Changes scales) and quantitatively with a semiautomated volumetric technique and an automatic lesion count. Statistical significance between groups was assessed with the chi2...

  6. Menopausal Hot Flashes and White Matter Hyperintensities

    Science.gov (United States)

    Thurston, Rebecca C.; Aizenstein, Howard J.; Derby, Carol A.; Sejdić, Ervin; Maki, Pauline M.

    2015-01-01

    Objective Hot flashes are the classic menopausal symptom. Emerging data links hot flashes to cardiovascular disease (CVD) risk, yet how hot flashes are related to brain health is poorly understood. We examined the relationship between hot flashes - measured via physiologic monitor and self-report - and white matter hyperintensities (WMH) among midlife women. Methods Twenty midlife women ages 40-60 without clinical CVD, with their uterus and both ovaries, and not taking hormone therapy were recruited. Women underwent 24 hours of ambulatory physiologic and diary hot flash monitoring to quantify hot flashes; magnetic resonance imaging to assess WMH burden; 72 hours of actigraphy and questionnaires to quantify sleep; and a blood draw, questionnaires, and physical measures to quantify demographics and CVD risk factors. Test of a priori hypotheses regarding relations between physiologically-monitored and self-reported wake and sleep hot flashes and WMH were conducted in linear regression models. Results More physiologically-monitored hot flashes during sleep were associated with greater WMH, controlling for age, race, and body mass index [beta(standard error)=.0002 (.0001), p=.03]. Findings persisted controlling for sleep characteristics and additional CVD risk factors. No relations were observed for self-reported hot flashes. Conclusions More physiologically-monitored hot flashes during sleep were associated with greater WMH burden among midlife women free of clinical CVD. Results suggest that relations between hot flashes and CVD risk observed in the periphery may extend to the brain. Future work should consider the unique role of sleep hot flashes in brain health. PMID:26057822

  7. Volumetric brain differences in children with periventricular T2-signal hyperintensities: a grouping by gestational age at birth.

    Science.gov (United States)

    Panigrahy, A; Barnes, P D; Robertson, R L; Back, S A; Sleeper, L A; Sayre, J W; Kinney, H C; Volpe, J J

    2001-09-01

    The purpose of this study was to compare both the volumes of the lateral ventricles and the cerebral white matter with gestational age at birth of children with periventricular white matter (PVWM) T2-signal hyperintensities on MR images. The spectrum of neuromotor abnormalities associated with these hyperintensities was also determined. We retrospectively reviewed the MR images of 70 patients who were between the ages of 1 and 5 years and whose images showed PVWM T2-signal hyperintensities. The patients were divided into premature (n = 35 children) and term (n = 35) groups depending on their gestational age at birth. Volumetric analysis was performed on four standardized axial sections using T2-weighted images. Volumes of interest were digitized on the basis of gray-scale densities of signal intensities to define the hemispheric cerebral white matter and lateral ventricles. Age-adjusted comparisons of volumetric measurements between the premature and term groups were performed using analysis of covariance. The volume of the cerebral white matter was smaller in the premature group (54 +/- 2 cm(3)) than in the term group (79 +/- 3 cm(3), p group (30 +/- 2 cm(3)) than among those in the term group (13 +/- 1 cm(3), p groups whose PVWM T2-signal hyperintensities did not correlate with any neuromotor abnormalities but were associated with seizures or developmental delays. The differences in volumetric measurements of cerebral white matter and lateral ventricles in children with PVWM T2-signal hyperintensities are related to their gestational age at birth. Several neurologic motor abnormalities are found in children with such hyperintensities.

  8. White matter hyperintensities segmentation: a new semi-automated method

    Directory of Open Access Journals (Sweden)

    Mariangela eIorio

    2013-12-01

    Full Text Available White matter hyperintensities (WMH are brain areas of increased signal on T2-weighted or fluid attenuated inverse recovery magnetic resonance imaging (MRI scans. In this study we present a new semi-automated method to measure WMH load that is based on the segmentation of the intensity histogram of fluid-attenuated inversion recovery images. Thirty patients with Mild Cognitive Impairment with variable WMH load were enrolled. The semi-automated WMH segmentation included: removal of non-brain tissue, spatial normalization, removal of cerebellum and brain stem, spatial filtering, thresholding to segment probable WMH, manual editing for correction of false positives and negatives, generation of WMH map and volumetric estimation of the WMH load. Accuracy was quantitatively evaluated by comparing semi-automated and manual WMH segmentations performed by two independent raters. Differences between the two procedures were assessed using Student’s t tests and similarity was evaluated using linear regression model and Dice Similarity Coefficient (DSC. The volumes of the manual and semi-automated segmentations did not statistically differ (t-value= -1.79, DF=29, p= 0.839 for rater 1; t-value= 1.113, DF=29, p= 0.2749 for rater 2, were highly correlated (R²= 0.921, F (1,29 =155,54, p

  9. White matter hyperintensities, systemic inflammation, brain growth, and cognitive functions in children exposed to air pollution.

    Science.gov (United States)

    Calderón-Garcidueñas, Lilian; Mora-Tiscareño, Antonieta; Styner, Martin; Gómez-Garza, Gilberto; Zhu, Hongtu; Torres-Jardón, Ricardo; Carlos, Esperanza; Solorio-López, Edelmira; Medina-Cortina, Humberto; Kavanaugh, Michael; D'Angiulli, Amedeo

    2012-01-01

    Air pollution exposures are linked to neuroinflammation and neuropathology in young urbanites. Forty percent of exposed children and young adults exhibit frontal tau hyperphosphorylation and 51% have amyloid-β diffuse plaques compared to 0% in low pollution controls. In older adults, white matter hyperintensities (WMH) are associated with cognitive deficits while inflammatory markers correlate with greater atrophy than expected for age. We investigated patterns of WMH, magnetic resonance imaging (MRI) volume growth, blood inflammatory mediators, and cognition in matched children from two urban cohorts: one severely and one minimally exposed to air pollution. Baseline and one year follow-up measurements of cognitive abilities, brain MRI volumes, and blood were collected in 20 Mexico City (MC) children (10 with WMH+, and 10 without WMH-) and 10 matched controls (WMH-). MC WMH- children display the profile of classical pro-inflammatory defensive responses: high interleukin 12, production of powerful pro-inflammatory cytokines, and low concentrations of key cytokines and chemokines associated with neuroprotection. MC WMH+ children exhibit a response involved in resolution of inflammation, immunoregulation, and tissue remodeling. The MC WMH+ group responded to the air pollution-associated brain volumetric alterations with white and grey matter volume increases in temporal, parietal, and frontal regions and better cognitive performance compared to MC WMH-. We conclude that complex modulation of cytokines and chemokines influences children's central nervous system structural and volumetric responses and cognitive correlates resulting from environmental pollution exposures. Identification of biomarkers associating systemic inflammation to brain growth is critical for detecting children at higher risk for cognitive deficits and neurodegeneration, thereby warranting early implementation of neuroprotective measures.

  10. Magnetic Resonance Finding of Acute Marchiafava-Bignami Disease with Diffuse Involvement: A Case Report

    International Nuclear Information System (INIS)

    Heo, Young Jin; Jeong, Hae Woong; In, Hyun Sin

    2011-01-01

    Marchiafava-Bignami disease (MBD) is a rare toxic disorder strongly associated with chronic alcoholism. It is characterized by progressive demyelination and necrosis of the corpus callosum. The process may extend to neighboring white matter and subcortical regions. We report a case of MBD in which fluid-attenuated inversion recovery and diffusion-weighted imaging revealed symmetrical hyperintense lesions with diffuse involvement of the corpus callosum, white matter, corticospinal tract, internal capsule, and middle cerebellar peduncle.

  11. Magnetic Resonance Finding of Acute Marchiafava-Bignami Disease with Diffuse Involvement: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Young Jin; Jeong, Hae Woong; In, Hyun Sin [Dept. of Radiology, Busan Paik Hospital, Inje University College of Medicine, Busan (Korea, Republic of)

    2011-11-15

    Marchiafava-Bignami disease (MBD) is a rare toxic disorder strongly associated with chronic alcoholism. It is characterized by progressive demyelination and necrosis of the corpus callosum. The process may extend to neighboring white matter and subcortical regions. We report a case of MBD in which fluid-attenuated inversion recovery and diffusion-weighted imaging revealed symmetrical hyperintense lesions with diffuse involvement of the corpus callosum, white matter, corticospinal tract, internal capsule, and middle cerebellar peduncle.

  12. White Matter Hyperintensities Are Under Strong Genetic Influence.

    Science.gov (United States)

    Sachdev, Perminder S; Thalamuthu, Anbupalam; Mather, Karen A; Ames, David; Wright, Margaret J; Wen, Wei

    2016-06-01

    The genetic basis of white matter hyperintensities (WMH) is still unknown. This study examines the heritability of WMH in both sexes and in different brain regions, and the influence of age. Participants from the Older Australian Twins Study were recruited (n=320; 92 monozygotic and 68 dizygotic pairs) who volunteered for magnetic resonance imaging scans and medical assessments. Heritability, that is, the ratio of the additive genetic variance to the total phenotypic variance, was estimated using the twin design. Heritability was high for total WMH volume (0.76), and for periventricular WMH (0.64) and deep WMH (0.77), and varied from 0.18 for the cerebellum to 0.76 for the occipital lobe. The genetic correlation between deep and periventricular WMH regions was 0.85, with one additive genetics factor accounting for most of the shared variance. Heritability was consistently higher in women in the cerebral regions. Heritability in deep but not periventricular WMH declined with age, in particular after the age of 75. WMH have a strong genetic influence but this is not uniform through the brain, being higher for deep than periventricular WMH and in the cerebral regions. The genetic influence is higher in women, and there is an age-related decline, most markedly for deep WMH. The data suggest some heterogeneity in the pathogenesis of WMH for different brain regions and for men and women. © 2016 American Heart Association, Inc.

  13. Diffusion-weighted MR imaging findings in carbon monoxide poisoning

    International Nuclear Information System (INIS)

    Teksam, M.; Casey, S.O.; Michel, E.; Liu, H.; Truwit, C.L.

    2002-01-01

    Diffusion-weighted MR imaging (DWI) of two patients with carbon monoxide (CO) poisoning demonstrated white matter and cortical hyperintensities. In one patient, the changes on the FLAIR sequence were more subtle than those on DWI. The DWI abnormality in this patient represented true restriction. In the second patient, repeated exposure to CO caused restricted diffusion. DWI may be helpful for earlier identification of the changes of acute CO poisoning. (orig.)

  14. A Voxel-Based Diffusion Tensor Imaging Study of White Matter in Bipolar Disorder

    OpenAIRE

    Mahon, Katie; Wu, Jinghui; Malhotra, Anil K.; Burdick, Katherine E.; DeRosse, Pamela; Ardekani, Babak A.; Szeszko, Philip R.

    2009-01-01

    There is evidence from post-mortem and magnetic resonance imaging studies that hyperintensities, oligodendrioglial abnormalities and gross white matter volumetric alterations play a role in the pathophysiology of bipolar disorder. There is also functional imaging evidence for a defect in frontal cortico-subcortical pathways in bipolar disorder, but the white matter comprising these pathways has not been well-investigated. Few studies have investigated white matter integrity in patients with b...

  15. Lower digit symbol substitution score in the oldest old is related to magnetization transfer and diffusion tensor imaging of the white matter.

    Directory of Open Access Journals (Sweden)

    Vijay eVenkatraman

    2011-09-01

    Full Text Available Background: Slowing information processing is common among community-dwelling elderly and it predicts greater mortality and disability risk. Slowing information processing is related to brain macro-structural abnormalities. Specifically, greater global atrophy and greater small vessel disease of the white matter have been associated to slower processing speed. However, community-dwelling elderly with such macro-structural abnormalities can maintain processing speed. The roles of brain micro-structure for slow processing in very old adults living in the community is uncertain, as epidemiological studies relating these brain markers to cognition and in the context of other health characteristics are sparse. Hypothesis: Information processing is cross-sectionally associated with white matter micro-structure independent of overt macro-structural abnormalities and also independent of health related characteristics. Methods: Imaging indices of micro-structure (diffusion tensor imaging, DTI, and magnetization transfer imaging, MTI, macro-structure (white matter hyperintensities, gray matter volume, Digit Symbol Substitution Test (DSST and health characteristics were measured in 272 elderly (mean age 83 years old, 43% men, 40% Black living in the community. Results: The DTI- and MTI-indices of micro-structure from the normal appearing white matter and not from the normal appearing gray matter were associated with DSST score independent of white matter hyperintensities and gray matter volumes. Associations were also independent of age, race, gender, mini-mental score, systolic blood pressure, prevalent myocardial infarction. Interpretation: DTI and MTI indices of normal appearing white matter are indicators of information processing speed in this cohort of very old adults living in the community. Since processing slowing is a potent index of mortality and disability, these indices may serve as biomarkers in prevention or treatment trials of disability.

  16. The correlation between white matter hyperintensity and balance disorder and fall risk: An observational, prospective cohort study

    Directory of Open Access Journals (Sweden)

    Dong-Chao Shen

    2016-09-01

    Full Text Available Objective: The presence of an association between white matter hyperintensity (WMH and the risk of falls in older people is uncertain, with little supporting prospective evidence available at present. We aimed to determine whether WMH was associated with dysfunctions of balance and gait, and other sensorimotor factors leading to falls, and the independent factors related to falls in older Chinese people. The protective effect of exercise against falls was also addressed. Methods: In a representative sample of hospital-based individuals aged 50 years and older in China, the patients' history of falls, magnetic resonance imaging data, scores on the 9-item Berg Balance Scale (BBS-9 test and timed up-and-go test (TUGT, and sensorimotor measures of computerized dynamic posturography (CDP were analyzed. Incident falls were recorded prospectively over a 12-month period. Using regression modeling, the association between the risk of falls and baseline WMH was estimated. Results: Only individuals with severe WMH were at an increased risk of falls, and CDP was more sensitive than BBS-9 in detecting WMH-related balance and gait dysfunction. However, WMH was not an independent predictor of falls. Taller height and overweight or obese body habitus were identified as novel protective factors for falls. Female, fall history, and increased TUGT score were identified as independent risk factors for falls in older Chinese people. Conclusion: Although WMH was associated with an increased risk of falls, it was not an independent predictor. Keywords: White matter hyperintensity, Balance disorder, Gait disorder, Fall risk

  17. The significance of diffusion weighted imaging for the diagnosis of pyogenic ventriculitis

    Energy Technology Data Exchange (ETDEWEB)

    Ihn, Yon Kwon; Hwang, Seong Su [College of Medicine, The Catholic University of Korea, Suwon (Korea, Republic of); Kim, Tae You [Willis Hospital, Seoul (Korea, Republic of)

    2007-08-15

    To evaluate the significance of diffusion weighted imaging (DWI) for the diagnosis of pyogenic ventriculitis. In this retrospective study, 9 patients with pyogenic ventricultis underwent a set of imaging sequences that included DWI, T1-and T2-weighted imaging. FLAIR and enhanced T1 weighted imaging. DWI consisted of an axial single shot spine echo EPI pulse sequence with b values of 0 and 1000 sec/mm{sup 2}. We evaluated the presence and signal intensity of ventricular debris, hydrocephalus, periventricular signal abnormality, and ependymal enhancement. The apparent diffusion coffiecient values of ventricular debris and cortical gray matter were calculated from the ADC map. In all patients, ventricular debris was hyperintense on the DWIs. A periventricular hyperintense signal was present in all cases on FLAIR and T2WI. Ependymal enhancement was detected in eight (89%) of 9 cases. A hydrocephalus was observed in 6 (67%) of 9 cases. The mean ADC value of ventricular debris was 0.735 {+-} 0.117 (10{sup -3} mm{sup 2}/sec). These ADC values were significantly lower than those for cortical gray matter (1.052 {+-} 0.149 (10{sup -3} mm{sup 2}/sec)). Ventricular debris was most conspicuous findings of ventriculitis on DWI. Areas of intraventricular hyperintensity on DWI corresponded to the decreased ADC values.

  18. MR Imaging Evaluation of Intracerebral Hemorrhages and T2 Hyperintense White Matter Lesions Appearing after Radiation Therapy in Adult Patients with Primary Brain Tumors.

    Science.gov (United States)

    Yoo, Dong Hyun; Song, Sang Woo; Yun, Tae Jin; Kim, Tae Min; Lee, Se-Hoon; Kim, Ji-Hoon; Sohn, Chul-Ho; Park, Sung-Hye; Park, Chul-Kee; Kim, Il Han; Choi, Seung Hong

    2015-01-01

    The purpose of our study was to determine the frequency and severity of intracerebral hemorrhages and T2 hyperintense white matter lesions (WMLs) following radiation therapy for brain tumors in adult patients. Of 648 adult brain tumor patients who received radiation therapy at our institute, magnetic resonance (MR) image data consisting of a gradient echo (GRE) and FLAIR T2-weighted image were available three and five years after radiation therapy in 81 patients. Intracerebral hemorrhage was defined as a hypointense dot lesion appearing on GRE images after radiation therapy. The number and size of the lesions were evaluated. The T2 hyperintense WMLs observed on the FLAIR sequences were graded according to the extent of the lesion. Intracerebral hemorrhage was detected in 21 (25.9%) and 35 (43.2) patients in the three- and five-year follow-up images, respectively. The number of intracerebral hemorrhages per patient tended to increase as the follow-up period increased, whereas the size of the intracerebral hemorrhages exhibited little variation over the course of follow-up. T2 hyperintense WMLs were observed in 27 (33.3%) and 32 (39.5) patients in the three and five year follow-up images, respectively. The age at the time of radiation therapy was significantly higher (p T2 hyperintense WMLs than in those without lesions. Intracerebral hemorrhages are not uncommon in adult brain tumor patients undergoing radiation therapy. The incidence and number of intracerebral hemorrhages increased over the course of follow-up. T2 hyperintense WMLs were observed in more than one-third of the study population.

  19. White matter hyperintensity and stroke lesion segmentation and differentiation using convolutional neural networks

    Directory of Open Access Journals (Sweden)

    R. Guerrero

    2018-01-01

    Full Text Available White matter hyperintensities (WMH are a feature of sporadic small vessel disease also frequently observed in magnetic resonance images (MRI of healthy elderly subjects. The accurate assessment of WMH burden is of crucial importance for epidemiological studies to determine association between WMHs, cognitive and clinical data; their causes, and the effects of new treatments in randomized trials. The manual delineation of WMHs is a very tedious, costly and time consuming process, that needs to be carried out by an expert annotator (e.g. a trained image analyst or radiologist. The problem of WMH delineation is further complicated by the fact that other pathological features (i.e. stroke lesions often also appear as hyperintense regions. Recently, several automated methods aiming to tackle the challenges of WMH segmentation have been proposed. Most of these methods have been specifically developed to segment WMH in MRI but cannot differentiate between WMHs and strokes. Other methods, capable of distinguishing between different pathologies in brain MRI, are not designed with simultaneous WMH and stroke segmentation in mind. Therefore, a task specific, reliable, fully automated method that can segment and differentiate between these two pathological manifestations on MRI has not yet been fully identified. In this work we propose to use a convolutional neural network (CNN that is able to segment hyperintensities and differentiate between WMHs and stroke lesions. Specifically, we aim to distinguish between WMH pathologies from those caused by stroke lesions due to either cortical, large or small subcortical infarcts. The proposed fully convolutional CNN architecture, called uResNet, that comprised an analysis path, that gradually learns low and high level features, followed by a synthesis path, that gradually combines and up-samples the low and high level features into a class likelihood semantic segmentation. Quantitatively, the proposed CNN

  20. Spaceflight-induced changes in white matter hyperintensity burden in astronauts.

    Science.gov (United States)

    Alperin, Noam; Bagci, Ahmet M; Lee, Sang H

    2017-11-21

    To assess the effect of weightlessness and the respective roles of CSF and vascular fluid on changes in white matter hyperintensity (WMH) burden in astronauts. We analyzed prespaceflight and postspaceflight brain MRI scans from 17 astronauts, 10 who flew a long-duration mission on the International Space Station (ISS) and 7 who flew a short-duration mission on the Space Shuttle. Automated analysis methods were used to determine preflight to postflight changes in periventricular and deep WMH, CSF, and brain tissue volumes in fluid-attenuated inversion recovery and high-resolution 3-dimensional T1-weighted imaging. Differences between cohorts and associations between individual measures were assessed. The short-term reversibility of the identified preflight to postflight changes was tested in a subcohort of 5 long-duration astronauts who had a second postflight MRI scan 1 month after the first postflight scan. Significant preflight to postflight changes were measured only in the long-duration cohort and included only the periventricular WMH and ventricular CSF volumes. Changes in deep WMH and brain tissue volumes were not significant in either cohort. The increase in periventricular WMH volume was significantly associated with an increase in ventricular CSF volume (ρ = 0.63, p = 0.008). A partial reversal of these increases was observed in the long-duration subcohort with a 1-month follow-up scan. Long-duration exposure to microgravity is associated with an increase in periventricular WMH in astronauts. This increase was linked to an increase in ventricular CSF volume documented in ISS astronauts. There was no associated change in or abnormal levels of WMH volumes in deep white matter as reported in U-2 high-altitude pilots. © 2017 American Academy of Neurology.

  1. Location Sensitive Deep Convolutional Neural Networks for Segmentation of White Matter Hyperintensities.

    Science.gov (United States)

    Ghafoorian, Mohsen; Karssemeijer, Nico; Heskes, Tom; van Uden, Inge W M; Sanchez, Clara I; Litjens, Geert; de Leeuw, Frank-Erik; van Ginneken, Bram; Marchiori, Elena; Platel, Bram

    2017-07-11

    The anatomical location of imaging features is of crucial importance for accurate diagnosis in many medical tasks. Convolutional neural networks (CNN) have had huge successes in computer vision, but they lack the natural ability to incorporate the anatomical location in their decision making process, hindering success in some medical image analysis tasks. In this paper, to integrate the anatomical location information into the network, we propose several deep CNN architectures that consider multi-scale patches or take explicit location features while training. We apply and compare the proposed architectures for segmentation of white matter hyperintensities in brain MR images on a large dataset. As a result, we observe that the CNNs that incorporate location information substantially outperform a conventional segmentation method with handcrafted features as well as CNNs that do not integrate location information. On a test set of 50 scans, the best configuration of our networks obtained a Dice score of 0.792, compared to 0.805 for an independent human observer. Performance levels of the machine and the independent human observer were not statistically significantly different (p-value = 0.06).

  2. Age and Alzheimer's pathology disrupt default mode network functioning via alterations in white matter microstructure but not hyperintensities.

    Science.gov (United States)

    Brown, Christopher A; Jiang, Yang; Smith, Charles D; Gold, Brian T

    2018-04-19

    The default mode network (DMN) comprises defined brain regions contributing to internally-directed thought processes. Reductions in task-induced deactivation in the DMN have been associated with increasing age and poorer executive task performance, but factors underlying these functional changes remain unclear. We investigated contributions of white matter (WM) microstructure, WM hyperintensities (WMH) and Alzheimer's pathology to age-related alterations in DMN function. Thirty-five cognitively normal older adults and 29 younger adults underwent working memory task fMRI and diffusion tensor imaging. In the older adults, we measured cerebrospinal fluid tau and Aβ 42 (markers of AD pathology), and WMH on FLAIR imaging (marker of cerebrovascular disease). We identified a set of regions showing DMN deactivation and a set of inter-connecting WM tracts (DMN-WM) common to both age groups. There were negative associations between DMN deactivation and task performance in older adults, consistent with previous studies. Decreased DMN deactivation was associated with AD pathology and WM microstructure but not with WMH volume. Mediation analyses showed that WM microstructure mediated declines in DMN deactivation associated with both aging and AD pathology. Together these results suggest that AD pathology may exert a "second-hit" on WM microstructure, over-and-above the effects of age, both contributing to diminished DMN deactivation in older adults. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Central pontine myelinolysis with a hyperintense lesion in diffusion weighted MRI: overview by means of a case report; Zentrale pontine Myelinolyse mit hyperintenser Laesion im diffusionsgewichteten MRT: Uebersicht anhand eines Fallberichtes

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, J.; Bewermeyer, H. [Neurologische Klinik, Kliniken der Stadt Koeln gGmbH, Krankenhaus Merheim, Koeln (Germany); Harzheim, A. [Radiologische Klinik, Kliniken der Stadt Koeln gGmbH, Krankenhaus Merheim, Koeln (Germany)

    2005-07-01

    Central pontine myelinolysis (CPM) is a demyelinating disease of the pons often associated with demyelination of other areas of the central nervous system (CNS). The etiology and pathogenesis of this disorder are still not fully understood. However, almost all cases of CPM are related to severe diseases or chronic alcoholism and occur in the setting of rapidly corrected serum hyponatremia and hypotonicity respectively. Depending on the involvement of other CNS structures, the clinical picture can vary considerably. Magnetic resonance imaging is the most sensitive investigation for the antemortem diagnosis of CPM, although the radiological findings lag behind and do not necessarily correlate with the clinical picture. Quite obviously diffusion-weighted imaging can be useful in the rapid diagnosis of CPM. This short review summarizes the current knowledge on the pathogenesis, clinical presentation, radiological findings, prognosis and therapeutic approaches of CPM. Characteristical clinical features and MR-findings including hyperintensity on diffusion-weighted images are illustrated by a typical case. (orig.)

  4. Reduced binding of Pittsburgh Compound-B in areas of white matter hyperintensities

    Directory of Open Access Journals (Sweden)

    A.E. Goodheart

    2015-01-01

    Full Text Available The amyloid imaging agent, Pittsburgh Compound-B, binds with high affinity to β-amyloid (Aβ in the brain, and it is well established that PiB also shows non-specific retention in white matter (WM. However, little is known about retention of PiB in areas of white matter hyperintensities (WMH, abnormalities commonly seen in older adults. Further, it is hypothesized that WMH are related to both cognitive dysfunction and Aβ deposition. The goal of the present study was to explore PiB retention in both normal-appearing WM (NAWM and WMH in a group of elderly, cognitively normal individuals. In a group of cognitively normal elderly (n = 64; 86.5 ± 2.6 years two analyses were applied: (1 ROIs were placed over periventricular areas in which WMH caps are commonly seen on all subjects, regardless of WMH burden or size. (2 Subject-specific maps of NAWM and WMH were co-registered with the PiB-PET images and mean SUVR values were calculated in these NAWM and WMH maps. PiB retention was significantly reduced in the ROIs of subjects with high WMH compared to subjects with low WMH. Additionally, in subjects with high WMH, there was significantly lower PiB retention in subject-specific maps of WMH compared to NAWM, which was not observed in subjects with low WMH, likely because of the small size of WMH maps in this group. These data suggest that WM in areas of WMH binds PiB less effectively than does normal WM. Further exploration of this phenomenon may lead to insights about the molecular basis of the non-specific retention of amyloid tracers in white matter.

  5. Central pontine myelinolysis with a hyperintense lesion in diffusion weighted MRI: overview by means of a case report

    International Nuclear Information System (INIS)

    Kuhn, J.; Bewermeyer, H.; Harzheim, A.

    2005-01-01

    Central pontine myelinolysis (CPM) is a demyelinating disease of the pons often associated with demyelination of other areas of the central nervous system (CNS). The etiology and pathogenesis of this disorder are still not fully understood. However, almost all cases of CPM are related to severe diseases or chronic alcoholism and occur in the setting of rapidly corrected serum hyponatremia and hypotonicity respectively. Depending on the involvement of other CNS structures, the clinical picture can vary considerably. Magnetic resonance imaging is the most sensitive investigation for the antemortem diagnosis of CPM, although the radiological findings lag behind and do not necessarily correlate with the clinical picture. Quite obviously diffusion-weighted imaging can be useful in the rapid diagnosis of CPM. This short review summarizes the current knowledge on the pathogenesis, clinical presentation, radiological findings, prognosis and therapeutic approaches of CPM. Characteristical clinical features and MR-findings including hyperintensity on diffusion-weighted images are illustrated by a typical case. (orig.)

  6. Reproducible segmentation of white matter hyperintensities using a new statistical definition.

    Science.gov (United States)

    Damangir, Soheil; Westman, Eric; Simmons, Andrew; Vrenken, Hugo; Wahlund, Lars-Olof; Spulber, Gabriela

    2017-06-01

    We present a method based on a proposed statistical definition of white matter hyperintensities (WMH), which can work with any combination of conventional magnetic resonance (MR) sequences without depending on manually delineated samples. T1-weighted, T2-weighted, FLAIR, and PD sequences acquired at 1.5 Tesla from 119 subjects from the Kings Health Partners-Dementia Case Register (healthy controls, mild cognitive impairment, Alzheimer's disease) were used. The segmentation was performed using a proposed definition for WMH based on the one-tailed Kolmogorov-Smirnov test. The presented method was verified, given all possible combinations of input sequences, against manual segmentations and a high similarity (Dice 0.85-0.91) was observed. Comparing segmentations with different input sequences to one another also yielded a high similarity (Dice 0.83-0.94) that exceeded intra-rater similarity (Dice 0.75-0.91). We compared the results with those of other available methods and showed that the segmentation based on the proposed definition has better accuracy and reproducibility in the test dataset used. Overall, the presented definition is shown to produce accurate results with higher reproducibility than manual delineation. This approach can be an alternative to other manual or automatic methods not only because of its accuracy, but also due to its good reproducibility.

  7. Change of diffusion anisotropy in patients with acute cerebral infarction using statistical parametric analysis

    International Nuclear Information System (INIS)

    Morita, Naomi; Harada, Masafumi; Uno, Masaaki; Furutani, Kaori; Nishitani, Hiromu

    2006-01-01

    We conducted statistical parametric comparison of fractional anisotropy (FA) images and quantified FA values to determine whether significant change occurs in the ischemic region. The subjects were 20 patients seen within 24 h after onset of ischemia. For statistical comparison of FA images, a sample FA image was coordinated by the Talairach template, and each FA map was normalized. Statistical comparison was conducted using statistical parametric mapping (SPM) 99. Regions of interest were set in the same region on apparent diffusion coefficient (ADC) and FA maps, the region being consistent with the hyperintense region on diffusion-weighted images (DWIs). The contralateral region was also measured to obtain asymmetry ratios of ADC and FA. Regions with areas of statistical significance on FA images were found only in the white matter of three patients, although the regions were smaller than hyperintense regions on DWIs. The mean ADC and FA ratios were 0.64±0.16 and 0.93±0.09, respectively, and the degree of FA change was less than that of the ADC change. Significant change in diffusion anisotropy was limited to the severely infarcted core of the white matter. We believe statistical comparison of FA maps to be useful for detecting different regions of diffusion anisotropy. (author)

  8. Mathematical models for the diffusion magnetic resonance signal abnormality in patients with prion diseases

    Directory of Open Access Journals (Sweden)

    Matteo Figini

    2015-01-01

    Full Text Available In clinical practice signal hyperintensity in the cortex and/or in the striatum on magnetic resonance (MR diffusion-weighted images (DWIs is a marker of sporadic Creutzfeldt–Jakob Disease (sCJD. MR diagnostic accuracy is greater than 90%, but the biophysical mechanisms underpinning the signal abnormality are unknown. The aim of this prospective study is to combine an advanced DWI protocol with new mathematical models of the microstructural changes occurring in prion disease patients to investigate the cause of MR signal alterations. This underpins the later development of more sensitive and specific image-based biomarkers. DWI data with a wide a range of echo times and diffusion weightings were acquired in 15 patients with suspected diagnosis of prion disease and in 4 healthy age-matched subjects. Clinical diagnosis of sCJD was made in nine patients, genetic CJD in one, rapidly progressive encephalopathy in three, and Gerstmann–Sträussler–Scheinker syndrome in two. Data were analysed with two bi-compartment models that represent different hypotheses about the histopathological alterations responsible for the DWI signal hyperintensity. A ROI-based analysis was performed in 13 grey matter areas located in affected and apparently unaffected regions from patients and healthy subjects. We provide for the first time non-invasive estimate of the restricted compartment radius, designed to reflect vacuole size, which is a key discriminator of sCJD subtypes. The estimated vacuole size in DWI hyperintense cortex was in the range between 3 and 10 µm that is compatible with neuropathology measurements. In DWI hyperintense grey matter of sCJD patients the two bi-compartment models outperform the classic mono-exponential ADC model. Both new models show that T2 relaxation times significantly increase, fast and slow diffusivities reduce, and the fraction of the compartment with slow/restricted diffusion increases compared to unaffected grey matter of

  9. Diffusion-weighted MRI in acute cerebral stroke

    Energy Technology Data Exchange (ETDEWEB)

    Takayama, Hideichi; Kobayashi, Masahito; Suga, Sadao; Kawase, Takeshi; Nagasawa, Masakazu; Sadanaga, Humiko; Okamura, Miyuki; Kanai, Yoshihiro; Mihara, Ban [Mihara Memorial Hospital, Isezaki, Gunma (Japan)

    1999-03-01

    Diffusion-weighted MRI has been demonstrated to be valuable in the assessment of cerebral stroke. Recent advance in MR systems of hardware with larger maximum gradient amplitude and faster imaging strategies, such as EPI, has made it possible to acquire whole brain diffusion-weighted imaging (DWI) in less that one minute. The purposes of this study are to evaluate clinical usefulness of DWI and to clarify pitfalls in the diagnosis of acute cerebral stroke. Seventeen patients with 18 ischemic lesions were studied. DWI were taken with 1.5 Tesla MRI (Magnetom Vision, Siemens, Germany) using EPI sequence. Fifteen lesions out of them (3 in cerebral cortex, 9 in basal ganglia/deep white matter and 3 in cerebellum) were studied serially at various times up to 147 days. Acute cerebral infarction was seen clearly as an area of hyperintensity with DWI and as hypointensity in apparent diffusion coefficient (ADC) maps which are indicative of decreased diffusion. DWI detected areas of hyperintense acute infarcts, as early as 2.5 hours after onset, which were not visualized on T{sub 2}-weighted image (T2WI). The lesion of cerebral infarction became isointense in ADC maps at 14-28 days after onset, whereas with DWI it became isointense at about 2 months. Because ADC changed earlier than DWI, ADC maps were useful for differentiate acute from nonacute lesion in cases of recurrent stroke within a short period. In a patient with transient global amnesia for 7 hours, DWI did not show any lesion at 8 hours. In terms of cerebral hemorrhage, lesions were seen as area of hyperintensity in DWI at 3 days and were not distinguishable from that of infarct. Despite limitations in the diagnosis of transient ischemia and cerebral hemorrhage, DWI is a useful technique for early detection of cerebral infarction, especially within the first 6 hours after stroke onset. (author)

  10. Diffusion-weighted MRI in acute cerebral stroke

    International Nuclear Information System (INIS)

    Takayama, Hideichi; Kobayashi, Masahito; Suga, Sadao; Kawase, Takeshi; Nagasawa, Masakazu; Sadanaga, Humiko; Okamura, Miyuki; Kanai, Yoshihiro; Mihara, Ban

    1999-01-01

    Diffusion-weighted MRI has been demonstrated to be valuable in the assessment of cerebral stroke. Recent advance in MR systems of hardware with larger maximum gradient amplitude and faster imaging strategies, such as EPI, has made it possible to acquire whole brain diffusion-weighted imaging (DWI) in less that one minute. The purposes of this study are to evaluate clinical usefulness of DWI and to clarify pitfalls in the diagnosis of acute cerebral stroke. Seventeen patients with 18 ischemic lesions were studied. DWI were taken with 1.5 Tesla MRI (Magnetom Vision, Siemens, Germany) using EPI sequence. Fifteen lesions out of them (3 in cerebral cortex, 9 in basal ganglia/deep white matter and 3 in cerebellum) were studied serially at various times up to 147 days. Acute cerebral infarction was seen clearly as an area of hyperintensity with DWI and as hypointensity in apparent diffusion coefficient (ADC) maps which are indicative of decreased diffusion. DWI detected areas of hyperintense acute infarcts, as early as 2.5 hours after onset, which were not visualized on T 2 -weighted image (T2WI). The lesion of cerebral infarction became isointense in ADC maps at 14-28 days after onset, whereas with DWI it became isointense at about 2 months. Because ADC changed earlier than DWI, ADC maps were useful for differentiate acute from nonacute lesion in cases of recurrent stroke within a short period. In a patient with transient global amnesia for 7 hours, DWI did not show any lesion at 8 hours. In terms of cerebral hemorrhage, lesions were seen as area of hyperintensity in DWI at 3 days and were not distinguishable from that of infarct. Despite limitations in the diagnosis of transient ischemia and cerebral hemorrhage, DWI is a useful technique for early detection of cerebral infarction, especially within the first 6 hours after stroke onset. (author)

  11. T1 hyperintense disc in alkaptonuria.

    Science.gov (United States)

    Sag, Alan A; Silbergleit, Richard; Olson, Rick E; Wilson, Jon; Krishnan, Anant

    2012-10-01

    Case report. To report a rare case of alkaptonuria presenting as a T1-hyperintense disc herniation. A 46-year-old man without previous diagnosis of alkaptonuria underwent evaluation for progressive back pain revealing a T1-hyperintense disc herniation at the L3-L4 level. Discectomy recovered a blackened disc that was pathologically confirmed to be nucleus pulposus with alkaptonuric involvement. The differential diagnosis of a T1-hyperintense, T2-hypointense disc on magnetic resonance imaging is discussed, with emphasis on the pathophysiology of alkaptonuria. A single patient is reported. Pathologically proven patient presentation with radiological and pathological images. We report a rare case of alkaptonuria presenting as a T1-hyperintense disc herniation.

  12. Anisotropic diffusion within human white matter

    International Nuclear Information System (INIS)

    Chenevert, T.L.; Brunberg, J.A.; Pipe, J.G.

    1990-01-01

    This paper reports on measurements performed to assess the impact of fiber orientation on the apparent diffusion coefficient of human white matter in vivo. Orthogonal section selection pulses and strong motion sensitization gradient pulses were used for localized diffusion measurement along an anteroposteriorly oriented 1 x 1 cm tissue column in the left cerebral hemisphere. This region was selected since white matter fiber orientations are reasonably well defined. Independent acquisitions with motion sensitivity along anteroposterior and right-left directions allowed study of diffusion anisotropy. Motion artifacts were minimized by magnitude summation after one-dimensional Fourier transform of frequency-encoded echoes; consequently, cardiac gating was not required. Five normal volunteers were studied on a 1.5-T clinical MR system

  13. Bilateral hyperintense basal ganglia on T1-weighted image

    International Nuclear Information System (INIS)

    Baik, Seung Kug; Ahn, Woo Hyun; Choi, Han Yong; Kim, Bong Gi

    1994-01-01

    Bilateral high signal intensity in basal ganglia on T1-weighted images is unusual, the purpose of this study is to describe the pattern of high signal intensity and underlying disease. During the last three years, 8 patients showed bilateral high signal intensity in basal ganglia on T1-weighted image, as compared with cerebral white matter. Authors analyzed the images and underlying causes retrospectively. Of 8 patients, 5 were male and 3 were female. The age ranged from 15 days to 79 years. All patient were examined by a 0.5T superconductive MRI. Images were obtained by spin echo multislice technique. Underlying causes were 4 cases of hepatopathy, 2 cases of calcium metabolism disorder, and one case each of neurofibromatosis and hypoxic brain injury. These process were bilateral in all cases and usually symmetric. In all cases the hyperintense areas were generally homogenous without mass effect or edema, although somewhat nodular appearance was seen in neurofibromatosis. Lesions were located in the globus pallidus and internal capsule in hepatopathy and neurofibromatosis, head of the caudate nucleus in disorder of calcum metabolism, and the globus pallidus in hypoxic brain injury. Although this study is limited by its patient population, bilateral hyperintense basal ganglia is associated with various disease entities. On analysis of hyperintense basal ganglia lesion, the knowledge of clinical information improved diagnostic accuracy

  14. Spaceflight Effect on White Matter Structural Integrity

    Science.gov (United States)

    Lee, Jessica K.; Kopplemans, Vincent; Paternack, Ofer; Bloomberg, Jacob J.; Mulavara, Ajitkumar P.; Seidler, Rachael D.

    2017-01-01

    Recent reports of elevated brain white matter hyperintensity (WMH) counts and volume in postflight astronaut MRIs suggest that further examination of spaceflight's impact on the microstructure of brain white matter is warranted. To this end, retrospective longitudinal diffusion-weighted MRI scans obtained from 15 astronauts were evaluated. In light of the recent reports of microgravity-induced cephalad fluid shift and gray matter atrophy seen in astronauts, we applied a technique to estimate diffusion tensor imaging (DTI) metrics corrected for free water contamination. This approach enabled the analysis of white matter tissue-specific alterations that are unrelated to fluid shifts, occurring from before spaceflight to after landing. After spaceflight, decreased fractional anisotropy (FA) values were detected in an area encompassing the superior and inferior longitudinal fasciculi and the inferior fronto-occipital fasciculus. Increased radial diffusivity (RD) and decreased axial diffusivity (AD) were also detected within overlapping regions. In addition, FA values in the corticospinal tract decreased and RD measures in the precentral gyrus white matter increased from before to after flight. The results show disrupted structural connectivity of white matter in tracts involved in visuospatial processing, vestibular function, and movement control as a result of spaceflight. The findings may help us understand the structural underpinnings of the extensive spaceflight-induced sensorimotor remodeling. Prospective longitudinal assessment of the white matter integrity in astronauts is needed to characterize the evolution of white matter microstructural changes associated with spaceflight, their behavioral consequences, and the time course of recovery. Supported by a grant from the National Space Biomedical Research Institute, NASA NCC 9-58.

  15. Conventional and Diffusion-Weighted MRI in the Evaluation of Methanol Poisoning. A case report

    International Nuclear Information System (INIS)

    Server, A.; Nakstad, P.Hj.; Dullerud, R.; Haakonsen, M.; Hovda, K.E.; Jacobsen, D.

    2003-01-01

    Cerebral lesions were studied in 2 methanol-poisoned patients using conventional magnetic resonance imaging (MRI). In 1 patient, diffusion-weighted MRI (DWI) was also performed. In this patient, conventional MRI showed symmetrical, bilateral increased signal in the lentiform nuclei, involving predominantly putamina, but also extending into the corona radiata, centrum semiovale and subcortical white matter. DWI showed decreased diffusion, which most probably reflects cytotoxic edema. In the other patient, fluid attenuated-inversion recovery (FLAIR) and T2-weighted images showed hyperintensity in the putamina, characteristic of post-necrotic changes

  16. Initial Incidence of White Matter Hyperintensities on MRI in Astronauts

    Science.gov (United States)

    Norcross, Jason; Sherman, Paul; McGuire, Steve; Kochunov, Peter

    2016-01-01

    Introduction: Previous literature has described the increase in white matter hyperintensity (WMH) burden associated with hypobaric exposure in the U-2 and altitude chamber operating personnel. Although astronauts have similar hypobaric exposure pressures to the U2 pilot population, astronauts have far fewer exposures and each exposure would be associated with a much lower level of decompression stress due to rigorous countermeasures to prevent decompression sickness. Therefore, we postulated that the WMH burden in the astronaut population would be less than in U2 pilots. Methods: Twenty-one post-flight de-identified astronaut MRIs (5 mm slice thickness FLAIR sequences) were evaluated for WMH count and volume. The only additional data provided was an age range of the astronauts (43-57) and if they had ever performed an EVA (13 yes, 8 no). Results: WMH count in these 21 astronaut MRI was 21.0 +/- 24.8 (mean+/- SD) and volume was 0.382 +/- 0.602 ml, which was significantly higher than previously published results for the U2 pilots. No significant differences between EVA and no EVA groups existed. Age range of astronaut population is not directly comparable to the U2 population. Discussion: With significantly less frequent (sometimes none) and less stressful hypobaric exposures, yet a much higher incidence of increased WMH, this indicates the possibility of additional mechanisms beyond hypobaric exposure. This increase unlikely to be attributable just to the differences in age between astronauts and U2 pilots. Forward work includes continuing review of post-flight MRI and evaluation of pre to post flight MRI changes if available. Data mining for potential WMH risk factors includes collection of age, sex, spaceflight experience, EVA hours, other hypobaric exposures, hyperoxic exposures, radiation, high performance aircraft experience and past medical history. Finally, neurocognitive and vision/eye results will be evaluated for any evidence of impairment linked to

  17. Association of Cardiac Hemodynamic Factors With Severity of White Matter Hyperintensities in Chronic Valvular Heart Disease.

    Science.gov (United States)

    Lee, Woo-Jin; Jung, Keun-Hwa; Ryu, Young Jin; Kim, Jeong-Min; Lee, Soon-Tae; Chu, Kon; Kim, Manho; Lee, Sang Kun; Roh, Jae-Kyu

    2018-01-01

    The cerebral white matter hyperintensity (WMH) is frequently noted in patients with chronic heart disease. Long-term alteration of cardiac hemodynamics might have an influence on the mechanism of cerebral WMH. To investigate the association between chronically altered cardiac hemodynamics and severity of cerebral WMH in patients with chronic valvular heart disease. This cross-sectional analysis identified 303 consecutive patients at a tertiary referral center between 2008 and 2016 who were 50 years or older, and diagnosed with severe chronic valvular heart disease and underwent cardiac catherization, echocardiography, and received brain magnetic resonance imaging. Among these patients, 71 with other demonstrated cardiac disease, central nervous system disease, and/or without sufficient catheterization data were excluded, and the remaining 232 patients were included in further analyses. The site and mechanism of valve diseases, as well as clinical and medication profiles, were reviewed. Cardiac catheterization parameters such as right atrial (RA) mean pressure, right ventricular pressure, and aortic mean pressure were obtained. Comprehensive echocardiographic hemodynamic markers such as left ventricular (LV) ejection fraction, LV mass index, LV end diastolic volume, cardiac index, and E/e' ratio were also obtained. White matter hyperintensity volume was quantitatively evaluated using volumetric analysis. This study included 232 patients (103 men [44.4%] and 129 women [55.6%]; mean [SD] (range) age, 65.6 [8.8] (51-88) years) in the final analysis. The mean (SD) WMH volume was 5.93 (7.14) mL (median [interquartile range], 4.33 [1.33-8.62] mL), and mean (SD) RA pressure was 10.0 (4.7) mm Hg. From the catheterization data, 147 patients (63.4%) were classified as having a disease involving the mitral valve; 93 (40.1%), aortic valve; 37 (15.9%), tricuspid valve; and 4 (1.7%), pulmonary valve. In multivariate linear regression analysis, adjusting the type and mechanism of

  18. Brain hyperintensity location determines outcome in the triad of impaired cognition, physical health and depressive symptoms: A cohort study in late life.

    Science.gov (United States)

    Murray, Alison; McNeil, Chris; Salarirad, Sima; Deary, Ian; Phillips, Louise; Whalley, Lawrence; Staff, Roger

    2016-01-01

    Brain hyperintensities, detectable with MRI, increase with age. They are associated with a triad of impairment in cognitive ability, depression and physical health. Here we test the hypothesis that the association between hyperintensities and cognitive ability, physical health and depressive symptoms depends on lesion location. 244 members of the Aberdeen 1936 Birth Cohort were recruited to this study. 227 participants completed brain MRI and their hyperintensities were scored using Scheltens's scale. 205 had complete imaging, cognitive, physical health and depressive symptom score data. The relationships between hyperintensity location and depressive symptoms, cognitive ability and physical health were examined by correlation and structural equation analysis. We found that depressive symptoms correlated with hyperintensity burden in the grey matter (r=0.14, p=0.04) and infratentorial regions (r=0.17, p=0.01). Infratentorial hyperintensities correlated with reduced peak expiratory flow rate (r=-0.26, pdepressive symptoms. Hyperintensities in the supratentorial and infratentorial regions were associated with reduced cognitive performance. Using structural equation modelling we found that the association between hyperintensities and depressive symptoms was mediated by negative effects on physical health and cognitive ability. Hyperintensities in deep brain structures are associated with depressive symptoms, mediated via impaired physical health and cognitive ability. Participants with higher cognitive ability and better physical health are at lower risk of depressive symptoms. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  19. Symmetrical central tegmental tract (CTT) hyperintense lesions on magnetic resonance imaging in children

    International Nuclear Information System (INIS)

    Yoshida, Shoko; Hayakawa, Katsumi; Yamamoto, Akira; Aida, Noriko; Okano, Souzo; Matsushita, Hiroko; Kanda, Toyoko; Yamori, Yuriko; Yoshida, Naoko; Hirota, Haruyo

    2009-01-01

    The central tegmental tract (CTT) is mainly the extrapyramidal tract connecting between the red nucleus and the inferior olivary nucleus. There are only a few case reports describing CTT abnormalities on magnetic resonance imaging (MRI) in children. Our purpose was to evaluate the frequency of CTT lesions and their characteristics on MRI, and to correlate the MR imaging findings with clinical features. We reviewed retrospectively the MR images of 392 children (215 boys and 177 girls) ranging in age from 1 to 6 years. To evaluate symmetrical CTT hyperintense lesions, we defined a CTT lesion as an area of bilateral symmetrical hyperintensity in the tegmentum pontis on both T2-weighted images and diffusion-weighted images in more than two slices. We measured the ADC (apparent diffusion coefficient) values of symmetrical CTT hyperintensity, and compared them with those of children without CTT abnormality. CTT lesions were detected in 20 (5.1%) of the 392 children. The mean ADC value for these 20 children was significantly lower than that of the normal CTT (p<0.001). On MR imaging, other than CTT lesions, associated parenchymal lesion included: none (n=6); other abnormalities, including periventricular leukomalacia (n=3); thin corpus callosum (n=3); ventricular dilatation (n=2); encephalopathy (n=2). Clinically, cerebral palsy was the most frequent clinical diagnosis (n=6), accounting for 30%, which was significantly more frequent than the prevalence of cerebral palsy among children without CTT lesions (13%) (n<0.05). CTT lesions were detected in 5.1% of all the children examined. Cerebral palsy was the most frequent clinical diagnosis. (orig.)

  20. Symmetrical central tegmental tract (CTT) hyperintense lesions on magnetic resonance imaging in children

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Shoko; Hayakawa, Katsumi; Yamamoto, Akira [Kyoto City Hospital, Department of Radiology, Kyoto (Japan); Aida, Noriko [Kanagawa Children' s Medical Center, Department of Radiology, Kyoto (Japan); Okano, Souzo; Matsushita, Hiroko [Kyoto City Hospital, Department of Pediatrics, Kyoto (Japan); Kanda, Toyoko; Yamori, Yuriko; Yoshida, Naoko; Hirota, Haruyo [St. Joseph Hospital for Handicapped Children, Department of Pediatric Neurology, Kyoto (Japan)

    2009-02-15

    The central tegmental tract (CTT) is mainly the extrapyramidal tract connecting between the red nucleus and the inferior olivary nucleus. There are only a few case reports describing CTT abnormalities on magnetic resonance imaging (MRI) in children. Our purpose was to evaluate the frequency of CTT lesions and their characteristics on MRI, and to correlate the MR imaging findings with clinical features. We reviewed retrospectively the MR images of 392 children (215 boys and 177 girls) ranging in age from 1 to 6 years. To evaluate symmetrical CTT hyperintense lesions, we defined a CTT lesion as an area of bilateral symmetrical hyperintensity in the tegmentum pontis on both T2-weighted images and diffusion-weighted images in more than two slices. We measured the ADC (apparent diffusion coefficient) values of symmetrical CTT hyperintensity, and compared them with those of children without CTT abnormality. CTT lesions were detected in 20 (5.1%) of the 392 children. The mean ADC value for these 20 children was significantly lower than that of the normal CTT (p<0.001). On MR imaging, other than CTT lesions, associated parenchymal lesion included: none (n=6); other abnormalities, including periventricular leukomalacia (n=3); thin corpus callosum (n=3); ventricular dilatation (n=2); encephalopathy (n=2). Clinically, cerebral palsy was the most frequent clinical diagnosis (n=6), accounting for 30%, which was significantly more frequent than the prevalence of cerebral palsy among children without CTT lesions (13%) (n<0.05). CTT lesions were detected in 5.1% of all the children examined. Cerebral palsy was the most frequent clinical diagnosis. (orig.)

  1. {sup 1}H and {sup 31}P magnetic resonance spectroscopic imaging of white matter signal hyperintensity areas in elderly subjects

    Energy Technology Data Exchange (ETDEWEB)

    Constans, J M [Department of Veterans Affairs Medical Center and University of California Magnetic Resonance Unit, San Francisco, CA (United States); [California Univ., San Francisco, CA (United States). Dept. of Radiology; Meyerhoff, D J [Department of Veterans Affairs Medical Center and University of California Magnetic Resonance Unit, San Francisco, CA (United States); [California Univ., San Francisco, CA (United States). Dept. of Radiology; Norman, D [California Univ., San Francisco, CA (United States). Dept. of Radiology; Fein, G [Department of Veterans Affairs Psychiatry Service, University of California, San Francisco, California (United States); [University of California, San Francisco, CA (United States). Dept. of Psychiatry; Weiner, M W [Department of Veterans Affairs Medical Center and University of California Magnetic Resonance Unit, San Francisco, CA (United States); [California Univ., San Francisco, CA (United States). Dept. of Radiology; [California Univ., San Francisco, CA (United States). Dept. of Medicine; [DVA Medical Center, Magnetic Resonance Spectroscopy Unit, San Francisco, CA (United States)

    1995-11-01

    White matter signal hyperintensities (WMSH) are commonly seen on MRI of elderly subjects. The purpose of this study was to characterize metabolic changes in the white matter of elderly subjects with extensive WMSH. We used water-suppressed proton ({sup 1}H) magnetic resonance spectroscopic imaging (MRSI) to compare six subjects with extensive WMSH with eight age-matched elderly subjects with minimal or absent WMSH, and phosphorus ({sup 31}P) MRSI to compare nine subjects with extensive WMSH and seven age-matched elderly subjects without extensive WMSH. Relative to region-matched tissue in elderly controls, extensive WMSH were associated with increased signal from choline-containing metabolites, no significant change of signal from N-acetylaspartate, and a trend to a decreased phosphomonoester (PME) resonance. These findings suggest that WMSH may be associated with an alteration of brain myelin phospholipids in the absence of axonal damage. There were no differences in energy phosphates, consistent with lack of ongoing brain ischemia. Within the group with extensive WMSH, PME resonance measures were significantly lower in WMSH than in contralateral normal-appearing white matter. These results provide information on pathophysiology of WMSH and a basis for comparison with WMSH in Alzheimer`s disease, vascular dementia, multiple sclerosis, and other diseases. (orig.). With 4 figs., 4 tabs.

  2. Financial literacy is associated with white matter integrity in old age.

    Science.gov (United States)

    Han, S Duke; Boyle, Patricia A; Arfanakis, Konstantinos; Fleischman, Debra; Yu, Lei; James, Bryan D; Bennett, David A

    2016-04-15

    Financial literacy, the ability to understand, access, and utilize information in ways that contribute to optimal financial outcomes, is important for independence and wellbeing in old age. We previously reported that financial literacy is associated with greater functional connectivity between brain regions in old age. Here, we tested the hypothesis that higher financial literacy would be associated with greater white matter integrity in old age. Participants included 346 persons without dementia (mean age=81.36, mean education=15.39, male/female=79/267, mean MMSE=28.52) from the Rush Memory and Aging Project. Financial literacy was assessed using a series of questions imbedded as part of an ongoing decision making study. White matter integrity was assessed with diffusion anisotropy measured with diffusion tensor magnetic resonance imaging (DTI). We tested the hypothesis that higher financial literacy is associated with higher diffusion anisotropy in white matter, adjusting for the effects of age, education, sex, and white matter hyperintense lesions. We then repeated the analysis also adjusting for cognitive function. Analyses revealed regions with significant positive associations between financial literacy and diffusion anisotropy, and many remained significant after accounting for cognitive function. White matter tracts connecting right hemisphere temporal-parietal brain regions were particularly implicated. Greater financial literacy is associated with higher diffusion anisotropy in white matter of nondemented older adults after adjusting for important covariates. These results suggest that financial literacy is positively associated with white matter integrity in old age. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  3. Unsupervised detection, quantification and localization of white matter hyper-intensities in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Gicquel, Sebastien

    1998-01-01

    White matter hyper-intensities (WMH) are punctual ischemic areas, related to arteriosclerosis, visible on T2- and PD-weighted MRI. They are present on elderly normal subjects, and their proportion vary between 27 to 83 % from study to study. This strong variability in their counting is especially caused by human observation, so an unsupervised detection tool is necessary. The method is based on the analysis of Tl-weighted MRI in sagittal orientation, and of T2- and PD-weighted MRI in transaxial orientation of a single subject. Detection of WMH is based on a segmentation phase, and contains a large number of pre- and post-processing. First, a correction of inhomogeneities due to instrumentation is applied, with the modelization of the intensity variations appearing on a homogenous object. and the Computing a correction matrix. The three MRI modalities are then placed in a single referential, using a MRI-PET registration method. The brain is segmented on the Tl-weighted MRI, resulting in a mask used to segment the two others modalities after registration. A multispectral bayesian segmentation algorithm extracts the white matter (WM) and objects likely to be WMH. A set of morphological operations generate an image representing WM and potential WMH. A second segmentation of this image, in two classes, results in a WMH mask. It is then possible to list the WMH, their size, their shape, and their position in the MRI referential. At last, the coordinates of the WMH centers of mass are placed into Talairach space, allowing statistical analysis on a large number of subjects. This method has been in part applied on a data base of 850 subjects. The four steps (correction of inhomogeneities, registration, segmentation of the brain and detection of AC and PC landmarks) result in a global success rate of 90 %. (author) [fr

  4. Performances of diffusion kurtosis imaging and diffusion tensor imaging in detecting white matter abnormality in schizophrenia

    Directory of Open Access Journals (Sweden)

    Jiajia Zhu

    2015-01-01

    Full Text Available Diffusion kurtosis imaging (DKI is an extension of diffusion tensor imaging (DTI, exhibiting improved sensitivity and specificity in detecting developmental and pathological changes in neural tissues. However, little attention was paid to the performances of DKI and DTI in detecting white matter abnormality in schizophrenia. In this study, DKI and DTI were performed in 94 schizophrenia patients and 91 sex- and age-matched healthy controls. White matter integrity was assessed by fractional anisotropy (FA, mean diffusivity (MD, axial diffusivity (AD, radial diffusivity (RD, mean kurtosis (MK, axial kurtosis (AK and radial kurtosis (RK of DKI and FA, MD, AD and RD of DTI. Group differences in these parameters were compared using tract-based spatial statistics (TBSS (P  AK (20% > RK (3% and RD (37% > FA (24% > MD (21% for DKI, and RD (43% > FA (30% > MD (21% for DTI. DKI-derived diffusion parameters (RD, FA and MD were sensitive to detect abnormality in white matter regions (the corpus callosum and anterior limb of internal capsule with coherent fiber arrangement; however, the kurtosis parameters (MK and AK were sensitive to reveal abnormality in white matter regions (the juxtacortical white matter and corona radiata with complex fiber arrangement. In schizophrenia, the decreased AK suggests axonal damage; however, the increased RD indicates myelin impairment. These findings suggest that diffusion and kurtosis parameters could provide complementary information and they should be jointly used to reveal pathological changes in schizophrenia.

  5. Genome-wide scan in Hispanics highlights candidate loci for brain white matter hyperintensities.

    Science.gov (United States)

    Beecham, Ashley; Dong, Chuanhui; Wright, Clinton B; Dueker, Nicole; Brickman, Adam M; Wang, Liyong; DeCarli, Charles; Blanton, Susan H; Rundek, Tatjana; Mayeux, Richard; Sacco, Ralph L

    2017-10-01

    To investigate genetic variants influencing white matter hyperintensities (WMHs) in the understudied Hispanic population. Using 6.8 million single nucleotide polymorphisms (SNPs), we conducted a genome-wide association study (GWAS) to identify SNPs associated with WMH volume (WMHV) in 922 Hispanics who underwent brain MRI as a cross-section of 2 community-based cohorts in the Northern Manhattan Study and the Washington Heights-Inwood Columbia Aging Project. Multiple linear modeling with PLINK was performed to examine the additive genetic effects on ln(WMHV) after controlling for age, sex, total intracranial volume, and principal components of ancestry. Gene-based tests of association were performed using VEGAS. Replication was performed in independent samples of Europeans, African Americans, and Asians. From the SNP analysis, a total of 17 independent SNPs in 7 genes had suggestive evidence of association with WMHV in Hispanics ( p < 1 × 10 -5 ) and 5 genes from the gene-based analysis with p < 1 × 10 -3 . One SNP (rs9957475 in GATA6 ) and 1 gene ( UBE2C ) demonstrated evidence of association ( p < 0.05) in the African American sample. Four SNPs with p < 1 × 10 -5 were shown to affect binding of SPI1 using RegulomeDB. This GWAS of 2 community-based Hispanic cohorts revealed several novel WMH-associated genetic variants. Further replication is needed in independent Hispanic samples to validate these suggestive associations, and fine mapping is needed to pinpoint causal variants.

  6. Signal intensity changes of normal brain at varying high b-value diffusion-weighted images using 3.0T MR scanner

    International Nuclear Information System (INIS)

    Lee, Jin Hee; Sohn, Chul Ho; Choi, Jin Soo

    2003-01-01

    Using diffusion-weighted MR imaging (DWI), to evaluate the signal intensity characteristics of normal adult brain as diffusion gradient strength (b value) increases from 1,000 to 3,000 s/mm 2 . Twenty-one healthy volunteers with neither neurologic symptoms nor pathologic findings at axial and sagittal T2-weighted MR imaging were involved in this study. All images were obtained with a 3.0T MR scanner. Six sets of spin-echo echo-planar images were acquired in the axial plane using progressively increasing strengths of diffusion-sensitizing gradients (corresponding to b values of 0, 1,000, 1,500, 2,000, 2,500, and 3,000 s/mm 2 ). All imaging parameters other than TE remained constant. Changes in normal white-gray matter signal intensity observed at variable b-value DWI were qualitatively analysed, and the signal-to-noise ratios (SNRs) in six anatomic regions (frontal and parietal white matter, genu and splenium corporis callosi, the posterior limb of the internal capsule, and the thalamus) quantitatively, and the ratios were averaged and compared with the average SNR of 1,000 s/mm DWI. As gradient strength increased from 1,000 to 3,000 s/mm 2 , both gray-and white-matter structures diminished in signal intensity, and images obtained at a b value of 3,000 s/mm 2 appeared very noisy. White matter became progressively hyperintense to gray matter as the diffusion sensitizing gradient increased, especially at the centrum semiovale, the posterior limb of the internal capsule, and the splenium corporis callosi, but the genu corporis callosi; showed exceptional intermediate low signal intensity. At quantitative assessment, the signal-to-noise ratio decreased as the diffusion sensitizing gradient increased. Relative to the images obtained at a b value of 1,000 s/mm 2 , average SNRs were 0.71 (b=1,500 s/mm 2 ), 0.52 (b=2,000 s/mm 2 ), 0.41 (b=2,500 s/mm 2 ), 0.33 (b=3,000 s/mm 2 ). As the diffusion sensitizing gradient increased, the signal-to-noise ratio of brain structures

  7. Diffusion tensor imaging of brain tumours at 3 T: A potential tool for assessing White matter tract invasion?

    Energy Technology Data Exchange (ETDEWEB)

    Price, S.J.; Burnet, N.G.; Donovan, T.; Green, H.A.L.; Pena, A.; Antoun, N.M.; Pickard, J.D.; Carpenter, T.A.; Gillard, J.H. E-mail: jhg21@cam.ac.uk

    2003-06-01

    AIM: To determine whether diffusion tensor imaging (DTI) of brain tumours can demonstrate abnormalities distal to hyperintensities on T2-weighted images, and possibly relate these to tumour grade. MATERIALS AND METHODS: Twenty patients with histologically confirmed supratentorial tumours, both gliomas (high and low grade) and metastases, were imaged at 3 T using T2-weighted and DTI sequences. Regions of interest (ROI) were drawn within the tumour, in white matter at various distances from the tumour and in areas of abnormality on DTI that appeared normal on T2-weighted images. The relative anisotropy index (RAI)--a measure of white matter organization, was calculated for these ROI. RESULTS: The abnormality on DTI was larger than that seen on T2-weighted images in 10/13 patients (77%) with high-grade gliomas. New abnormalities were seen in the contralateral white matter in 4/13 (30%) of these cases. In these high-grade tumours the RAI in areas of white matter disruption with normal appearance on T2-weighted images was reduced (0.19{+-}0.04). Even excluding patients with previous radiotherapy this difference remains significant. In all non high-grade tumours (WHO grade II gliomas and metastases) the tumour extent on DTI was identical to the abnormalities shown on T2-weighted imaging and RAI measurements were not reduced (0.3{+-}0.04). CONCLUSIONS: Subtle white matter disruption can be identified using DTI in patients with high-grade gliomas. Such disruption is not identified in association with metastases or low-grade gliomas despite these tumours producing significant mass effect and oedema. We suggest the changes in DTI may be due to tumour infiltration and that the DTI may provide a useful method of detecting occult white matter invasion by gliomas.

  8. Diffusion tensor imaging of brain tumours at 3 T: A potential tool for assessing White matter tract invasion?

    International Nuclear Information System (INIS)

    Price, S.J.; Burnet, N.G.; Donovan, T.; Green, H.A.L.; Pena, A.; Antoun, N.M.; Pickard, J.D.; Carpenter, T.A.; Gillard, J.H.

    2003-01-01

    AIM: To determine whether diffusion tensor imaging (DTI) of brain tumours can demonstrate abnormalities distal to hyperintensities on T2-weighted images, and possibly relate these to tumour grade. MATERIALS AND METHODS: Twenty patients with histologically confirmed supratentorial tumours, both gliomas (high and low grade) and metastases, were imaged at 3 T using T2-weighted and DTI sequences. Regions of interest (ROI) were drawn within the tumour, in white matter at various distances from the tumour and in areas of abnormality on DTI that appeared normal on T2-weighted images. The relative anisotropy index (RAI)--a measure of white matter organization, was calculated for these ROI. RESULTS: The abnormality on DTI was larger than that seen on T2-weighted images in 10/13 patients (77%) with high-grade gliomas. New abnormalities were seen in the contralateral white matter in 4/13 (30%) of these cases. In these high-grade tumours the RAI in areas of white matter disruption with normal appearance on T2-weighted images was reduced (0.19±0.04). Even excluding patients with previous radiotherapy this difference remains significant. In all non high-grade tumours (WHO grade II gliomas and metastases) the tumour extent on DTI was identical to the abnormalities shown on T2-weighted imaging and RAI measurements were not reduced (0.3±0.04). CONCLUSIONS: Subtle white matter disruption can be identified using DTI in patients with high-grade gliomas. Such disruption is not identified in association with metastases or low-grade gliomas despite these tumours producing significant mass effect and oedema. We suggest the changes in DTI may be due to tumour infiltration and that the DTI may provide a useful method of detecting occult white matter invasion by gliomas

  9. An automated procedure for the assessment of white matter hyperintensities by multispectral (T1, T2, PD) MRI and an evaluation of its between-centre reproducibility based on two large community databases

    International Nuclear Information System (INIS)

    Maillard, Pauline; Delcroix, Nicolas; Crivello, Fabrice; Gicquel, Sebastien; Joliot, Marc; Tzourio-Mazoyer, Nathalie; Dufouil, Carole; Alperovitch, Annick; Tzourio, Christophe; Mazoyer, Bernard

    2008-01-01

    An automated procedure for the detection, quantification, localization and statistical mapping of white matter hyperintensities (WMH) on T2-weighted magnetic resonance (MR) images is presented and validated based on the results of a between-centre reproducibility study. The first step is the identification of white matter (WM) tissue using a multispectral (T1, T2, PD) segmentation. In a second step, WMH are identified within the WM tissue by segmenting T2 images, isolating two different classes of WMH voxels - low- and high-contrast WMH voxels, respectively. The reliability of the whole procedure was assessed by applying it to the analysis of two large MR imaging databases (n = 650 and n710, respectively) of healthy elderly subjects matched for demographic characteristics. Average overall WMH load and spatial distribution were found to be similar in the two samples, (1.81 and 1.79% of the WM volume, respectively). White matter hyperintensity load was found to be significantly associated with both age and high blood pressure, with similar effects in both samples. With specific reference to the 650 subject cohort, we also found that WMH load provided by this automated procedure was significantly associated with visual grading of the severity of WMH, as assessed by a trained neurologist. The results show that this method is sensitive, well correlated with semi-quantitative visual rating and highly reproducible. (orig.)

  10. An automated procedure for the assessment of white matter hyperintensities by multispectral (T1, T2, PD) MRI and an evaluation of its between-centre reproducibility based on two large community databases

    Energy Technology Data Exchange (ETDEWEB)

    Maillard, Pauline; Delcroix, Nicolas; Crivello, Fabrice; Gicquel, Sebastien; Joliot, Marc; Tzourio-Mazoyer, Nathalie [GIP Cyceron, Centre d' Imagerie-Neurosciences et Applications aux Pathologies, CI-NAPS, CNRS, CEA, Universite de Caen/Universite Paris Descartes, Boulevard Becquerel, BP 5229, Caen (France); Dufouil, Carole; Alperovitch, Annick; Tzourio, Christophe [Universite Pierre et Marie Curie, INSERM U708, Neuroepidemiologie, Paris (France); Mazoyer, Bernard [GIP Cyceron, Centre d' Imagerie-Neurosciences et Applications aux Pathologies, CI-NAPS, CNRS, CEA, Universite de Caen/Universite Paris Descartes, Boulevard Becquerel, BP 5229, Caen (France); Institut Universitaire de France, Paris (France); CHU du Caen, Unite IRM, Caen (France)

    2008-01-15

    An automated procedure for the detection, quantification, localization and statistical mapping of white matter hyperintensities (WMH) on T2-weighted magnetic resonance (MR) images is presented and validated based on the results of a between-centre reproducibility study. The first step is the identification of white matter (WM) tissue using a multispectral (T1, T2, PD) segmentation. In a second step, WMH are identified within the WM tissue by segmenting T2 images, isolating two different classes of WMH voxels - low- and high-contrast WMH voxels, respectively. The reliability of the whole procedure was assessed by applying it to the analysis of two large MR imaging databases (n = 650 and n= 710, respectively) of healthy elderly subjects matched for demographic characteristics. Average overall WMH load and spatial distribution were found to be similar in the two samples, (1.81 and 1.79% of the WM volume, respectively). White matter hyperintensity load was found to be significantly associated with both age and high blood pressure, with similar effects in both samples. With specific reference to the 650 subject cohort, we also found that WMH load provided by this automated procedure was significantly associated with visual grading of the severity of WMH, as assessed by a trained neurologist. The results show that this method is sensitive, well correlated with semi-quantitative visual rating and highly reproducible. (orig.)

  11. Impact of Strategically Located White Matter Hyperintensities on Cognition in Memory Clinic Patients with Small Vessel Disease.

    Science.gov (United States)

    Biesbroek, J Matthijs; Weaver, Nick A; Hilal, Saima; Kuijf, Hugo J; Ikram, Mohammad Kamran; Xu, Xin; Tan, Boon Yeow; Venketasubramanian, Narayanaswamy; Postma, Albert; Biessels, Geert Jan; Chen, Christopher P L H

    2016-01-01

    Studies on the impact of small vessel disease (SVD) on cognition generally focus on white matter hyperintensity (WMH) volume. The extent to which WMH location relates to cognitive performance has received less attention, but is likely to be functionally important. We examined the relation between WMH location and cognition in a memory clinic cohort of patients with sporadic SVD. A total of 167 patients with SVD were recruited from memory clinics. Assumption-free region of interest-based analyses based on major white matter tracts and voxel-wise analyses were used to determine the association between WMH location and executive functioning, visuomotor speed and memory. Region of interest-based analyses showed that WMHs located particularly within the anterior thalamic radiation and forceps minor were inversely associated with both executive functioning and visuomotor speed, independent of total WMH volume. Memory was significantly associated with WMH volume in the forceps minor, independent of total WMH volume. An independent assumption-free voxel-wise analysis identified strategic voxels in these same tracts. Region of interest-based analyses showed that WMH volume within the anterior thalamic radiation explained 6.8% of variance in executive functioning, compared to 3.9% for total WMH volume; WMH volume within the forceps minor explained 4.6% of variance in visuomotor speed and 4.2% of variance in memory, compared to 1.8% and 1.3% respectively for total WMH volume. Our findings identify the anterior thalamic radiation and forceps minor as strategic white matter tracts in which WMHs are most strongly associated with cognitive impairment in memory clinic patients with SVD. WMH volumes in individual tracts explained more variance in cognition than total WMH burden, emphasizing the importance of lesion location when addressing the functional consequences of WMHs.

  12. White matter hyperintensities in middle-aged adults with childhood-onset type 1 diabetes

    Science.gov (United States)

    Nunley, Karen A.; Ryan, Christopher M.; Orchard, Trevor J.; Aizenstein, Howard J.; Jennings, J. Richard; Ryan, John; Zgibor, Janice C.; Boudreau, Robert M.; Costacou, Tina; Maynard, John D.; Miller, Rachel G.

    2015-01-01

    Objective: Although microvascular complications are common in type 1 diabetes mellitus (T1DM), few studies have quantified the severity, risk factors, and implications of cerebral microvascular damage in these patients. As life expectancy in patients with T1DM increases, patients are exposed to age- and disease-related factors that may contribute to cerebral microvascular disease. Methods: Severity and volume of white matter hyperintensities (WMH) and infarcts were quantified in 97 middle-aged patients with childhood-onset T1DM (mean age and duration: 50 and 41 years, respectively) and 81 non-T1DM adults (mean age: 48 years), concurrent with cognitive and health-related measures. Results: Compared with non-T1DM participants, patients had more severe WMH (Fazekas scores 2 and 3 compared with Fazekas score 1, p the group differences in processing speed (13% for digit symbol, 11% for pegboard, both p ≤ 0.05). Among patients, prevalent neuropathies and smoking tripled the odds of high WMH burden, independent of age or disease duration. Associations between measures of blood pressure or hyperglycemia and WMH were not significant. Conclusions: Clinically relevant WMH are evident earlier among middle-aged patients with childhood-onset T1DM and are related to the slower information processing frequently observed in T1DM. Brain imaging in patients with T1DM who have cognitive difficulties, especially those with neuropathies, may help uncover cerebral microvascular damage. Longitudinal studies are warranted to fully characterize WMH development, risk factors, and long-term effects on cognition. PMID:25904692

  13. Diffusion tensor MR imaging in neurofibromatosis type 1: expanding the knowledge of microstructural brain abnormalities

    International Nuclear Information System (INIS)

    Ferraz-Filho, Jose R.L.; Muniz, Marcos P.; Souza, Antonio S.; Rocha, Antonio J. da; Goloni-Bertollo, Eny M.; Pavarino-Bertelli, Erika C.

    2012-01-01

    Neurofibromatosis type 1 (NF1) is a hereditary disease with a dominant autosomal pattern. In children and adolescents, it is frequently associated with the appearance of T2-weighted hyperintensities in the brain's white matter. MRI with diffusion tensor imaging (DTI) is used to detect white matter abnormalities by measuring fractional anisotropy (FA). This study employed DTI to evaluate the relationship between FA patterns and the findings of T2 sequences, with the aim of improving our understanding of anatomical changes and microstructural brain abnormalities in individuals with NF1. Forty-four individuals with NF1 and 20 control subjects were evaluated. The comparative analysis of FA between NF1 and control groups was based on four predetermined anatomical regions of the brain hemispheres (basal ganglia, cerebellum, pons, thalamus) and related the presence or absence of T2-weighted hyperintensities in the brain, which are called unidentified bright objects (UBOs). The FA values between the groups demonstrated statistically significant differences (P ≤ 0.05) for the cerebellum and thalamus in patients with NF1, independent of the occurrence of UBOs. Diffusion tensor MR imaging confirms the influence of UBOs in the decrease of FA values in this series of patients with NF1. Additionally, this technique allows the characterization of microstructural abnormalities even in some brain regions that appear normal in conventional MR sequences. (orig.)

  14. Diffusion in condensed matter methods, materials, models

    CERN Document Server

    Kärger, Jörg

    2005-01-01

    Diffusion as the process of particle transport due to stochastic movement is a phenomenon of crucial relevance for a large variety of processes and materials. This comprehensive, handbook- style survey of diffusion in condensed matter gives detailed insight into diffusion as the process of particle transport due to stochastic movement. Leading experts in the field describe in 23 chapters the different aspects of diffusion, covering microscopic and macroscopic experimental techniques and exemplary results for various classes of solids, liquids and interfaces as well as several theoretical concepts and models. Students and scientists in physics, chemistry, materials science, and biology will benefit from this detailed compilation.

  15. Probing white-matter microstructure with higher-order diffusion tensors and susceptibility tensor MRI

    Science.gov (United States)

    Liu, Chunlei; Murphy, Nicole E.; Li, Wei

    2012-01-01

    Diffusion MRI has become an invaluable tool for studying white matter microstructure and brain connectivity. The emergence of quantitative susceptibility mapping and susceptibility tensor imaging (STI) has provided another unique tool for assessing the structure of white matter. In the highly ordered white matter structure, diffusion MRI measures hindered water mobility induced by various tissue and cell membranes, while susceptibility sensitizes to the molecular composition and axonal arrangement. Integrating these two methods may produce new insights into the complex physiology of white matter. In this study, we investigated the relationship between diffusion and magnetic susceptibility in the white matter. Experiments were conducted on phantoms and human brains in vivo. Diffusion properties were quantified with the diffusion tensor model and also with the higher order tensor model based on the cumulant expansion. Frequency shift and susceptibility tensor were measured with quantitative susceptibility mapping and susceptibility tensor imaging. These diffusion and susceptibility quantities were compared and correlated in regions of single fiber bundles and regions of multiple fiber orientations. Relationships were established with similarities and differences identified. It is believed that diffusion MRI and susceptibility MRI provide complementary information of the microstructure of white matter. Together, they allow a more complete assessment of healthy and diseased brains. PMID:23507987

  16. Cerebral and cerebellar ADC values during a migraine attack

    Energy Technology Data Exchange (ETDEWEB)

    Degirmenci, Bumin; Haktanir, Alpay; Albayrak, Ramazan; Acar, Murat [University of Kocatepe, Department of Radiology, Faculty of Medicine, Afyon (Turkey); Yaman, Mehmet [University of Kocatepe, Department of Neurology, Faculty of Medicine, Afyon (Turkey)

    2007-05-15

    We investigated the diffusion-weighted MRI changes, apparent diffusion coefficient (ADC) values, and conventional MRI findings in specific brain areas during migraine attacks in patients with and without aura. Included in the study were 22 patients (2 male, 20 female) aged between 17 and 49 years who were diagnosed as having migraine according to the diagnostic criteria of the International Headache Society. Also included in the study were 18 age- and sex-matched healthy volunteers. Hyperintense lesions were evaluated in conventional MR images. Heavily diffusion-weighted images, ADC maps, and segmented ADC maps generated for regional ADC (rADC) measurements, were also studied. ADC values from specific brain areas were used with appropriate region of interests (ROI). Migraine with aura was diagnosed in 13 patients and migraine without aura was diagnosed in 9 patients. A total of 23 hyperintense lesions within the periventricular white matter and deep white matter were detected in five patients (21.8%). All of these hyperintense lesions were seen in migraine patients with aura. In only one patient did a hyperintense lesion show an increased diffusion pattern on diffusion-weighted images and ADC maps. One hyperintense lesion was detected in the control group (5.5%). There was no significant difference in ADC values between the migraine and control groups. T2-weighted hyperintense lesions were significantly more frequent in migraine patients especially in those with aura than in the control group. No diffusion alterations in diffusion-weighted images were detected in the infra- and supratentorial brain areas during migraine attacks in patients with and without aura. (orig.)

  17. Cerebral and cerebellar ADC values during a migraine attack

    International Nuclear Information System (INIS)

    Degirmenci, Bumin; Haktanir, Alpay; Albayrak, Ramazan; Acar, Murat; Yaman, Mehmet

    2007-01-01

    We investigated the diffusion-weighted MRI changes, apparent diffusion coefficient (ADC) values, and conventional MRI findings in specific brain areas during migraine attacks in patients with and without aura. Included in the study were 22 patients (2 male, 20 female) aged between 17 and 49 years who were diagnosed as having migraine according to the diagnostic criteria of the International Headache Society. Also included in the study were 18 age- and sex-matched healthy volunteers. Hyperintense lesions were evaluated in conventional MR images. Heavily diffusion-weighted images, ADC maps, and segmented ADC maps generated for regional ADC (rADC) measurements, were also studied. ADC values from specific brain areas were used with appropriate region of interests (ROI). Migraine with aura was diagnosed in 13 patients and migraine without aura was diagnosed in 9 patients. A total of 23 hyperintense lesions within the periventricular white matter and deep white matter were detected in five patients (21.8%). All of these hyperintense lesions were seen in migraine patients with aura. In only one patient did a hyperintense lesion show an increased diffusion pattern on diffusion-weighted images and ADC maps. One hyperintense lesion was detected in the control group (5.5%). There was no significant difference in ADC values between the migraine and control groups. T2-weighted hyperintense lesions were significantly more frequent in migraine patients especially in those with aura than in the control group. No diffusion alterations in diffusion-weighted images were detected in the infra- and supratentorial brain areas during migraine attacks in patients with and without aura. (orig.)

  18. Diffusion-weighted magnetic resonance imaging of cerebral white matter development

    International Nuclear Information System (INIS)

    Prayer, Daniela.; Prayer, Lucas

    2003-01-01

    Diffusion-weighted magnetic resonance imaging (DWI) has become a sensitive tool to monitor white matter development. Different applications of diffusion-weighted techniques provide information about premyelinating, myelinating, and postmyelinating states of white matter maturation. Mirroring maturational processes on the cellular level, DWI has to be regarded as a morphological method as well as a functional instrument, giving insight into molecular processes during the formation of axons and myelin sheets and into the steric arrangement of white matter tracts the formation of which is strongly influenced by their function

  19. Diffusion-weighted magnetic resonance imaging of cerebral white matter development

    Energy Technology Data Exchange (ETDEWEB)

    Prayer, Daniela. E-mail: daniela.prayer@univie.ac.at; Prayer, Lucas

    2003-03-01

    Diffusion-weighted magnetic resonance imaging (DWI) has become a sensitive tool to monitor white matter development. Different applications of diffusion-weighted techniques provide information about premyelinating, myelinating, and postmyelinating states of white matter maturation. Mirroring maturational processes on the cellular level, DWI has to be regarded as a morphological method as well as a functional instrument, giving insight into molecular processes during the formation of axons and myelin sheets and into the steric arrangement of white matter tracts the formation of which is strongly influenced by their function.

  20. UBO Detector - A cluster-based, fully automated pipeline for extracting white matter hyperintensities.

    Science.gov (United States)

    Jiang, Jiyang; Liu, Tao; Zhu, Wanlin; Koncz, Rebecca; Liu, Hao; Lee, Teresa; Sachdev, Perminder S; Wen, Wei

    2018-07-01

    We present 'UBO Detector', a cluster-based, fully automated pipeline for extracting and calculating variables for regions of white matter hyperintensities (WMH) (available for download at https://cheba.unsw.edu.au/group/neuroimaging-pipeline). It takes T1-weighted and fluid attenuated inversion recovery (FLAIR) scans as input, and SPM12 and FSL functions are utilised for pre-processing. The candidate clusters are then generated by FMRIB's Automated Segmentation Tool (FAST). A supervised machine learning algorithm, k-nearest neighbor (k-NN), is applied to determine whether the candidate clusters are WMH or non-WMH. UBO Detector generates both image and text (volumes and the number of WMH clusters) outputs for whole brain, periventricular, deep, and lobar WMH, as well as WMH in arterial territories. The computation time for each brain is approximately 15 min. We validated the performance of UBO Detector by showing a) high segmentation (similarity index (SI) = 0.848) and volumetric (intraclass correlation coefficient (ICC) = 0.985) agreement between the UBO Detector-derived and manually traced WMH; b) highly correlated (r 2  > 0.9) and a steady increase of WMH volumes over time; and c) significant associations of periventricular (t = 22.591, p deep (t = 14.523, p < 0.001) WMH volumes generated by UBO Detector with Fazekas rating scores. With parallel computing enabled in UBO Detector, the processing can take advantage of multi-core CPU's that are commonly available on workstations. In conclusion, UBO Detector is a reliable, efficient and fully automated WMH segmentation pipeline. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. Revealing dark matter substructure with anisotropies in the diffuse gamma-ray background

    OpenAIRE

    Siegal-Gaskins, Jennifer M.

    2008-01-01

    The majority of gamma-ray emission from Galactic dark matter annihilation is likely to be detected as a contribution to the diffuse gamma-ray background. I show that dark matter substructure in the halo of the Galaxy induces characteristic anisotropies in the diffuse background that could be used to determine the small-scale dark matter distribution. I calculate the angular power spectrum of the emission from dark matter substructure for several models of the subhalo population, and show that...

  2. Usefulness of Diffusion Tensor Imaging of White Matter in Alzheimer Disease and Vascular Dementia

    International Nuclear Information System (INIS)

    Sugihara, S.; Kinoshita, T.; Matsusue, E.; Fujii, S.; Ogawa, T.

    2004-01-01

    Purpose: To evaluate the usefulness of diffusion tensor imaging in detecting the water diffusivity caused by neuro pathological change in Alzheimer disease and vascular dementia. Material and Methods: Twenty patients with Alzheimer disease, 20 with vascular dementia, and 10 control subjects were examined. Diffusion tensor imaging applied diffusion gradient encoding in six non-collinear directions. Fractional anisotropy values were compared in the genu and splenium of the corpus callosum, and anterior and posterior white matter among the three groups. Results: In the patients with Alzheimer disease, fractional anisotropy values of the posterior white matter were significantly lower than those of controls. In patients with vascular dementia, fractional anisotropy values of the anterior white matter tended to be lower than those of the posterior white matter (P=0.07). Conclusion: Diffusion tensor imaging reflects the neuro pathological changes in the white matter, and may be useful in the diagnosis of Alzheimer disease and vascular dementia. Keywords: Alzheimer disease, .; diffusion tensor imaging, .; vascular dementia

  3. Quantitative analysis of hyperintensity rim sign surrounding MS plaque on T1 weighted images. Comparison with lacunar infarction

    International Nuclear Information System (INIS)

    Komura, Shinji; Ozaki, Yutaka

    2008-01-01

    This study evaluated the incidence of MR findings showing a hyperintensity rim surrounding multiple sclerosis (MS) plaque on T1-weighted images using image analysis software. We also evaluate the efficacy of this MR finding for differentiating between MS and lacunar infarction. We reviewed T1-weighted images in clinically diagnosed MS patients who underwent MR imaging between February 2006 and July 2007. Two hundred and thirty-nine nodular low signal intensities over 5 mm in minimal diameter were observed in 39 MS patients. To compare the incidence of MR findings, we also reviewed T1-weighted images in randomly selected lacunar infarction patients who underwent MR imaging during the same period. There were 51 nodular low signal intensities over 5 mm in shortest diameter in 34 lacunar infarction patients. After standardization of MR images, we calculated each signal intensity at the plaque margin (M.I.) and surrounding white matter (Wh.I.) using plot-profile analysis. We judged that hyperintensity rim sign was positive when the M.I/Wh.I. ratio was over 1.05. Among 239 T1 low intensity plaques in 39 MS patients, hyperintensity rim sign was positive for 81 (33.9%) plaques in 21 (53.8%) patients. Among 51 T1 low intensity lesions in 34 lacunar infarction patients, hyperintensity rim sign was positive for only one lesion in one patient. There were significant differences in the incidence of hyperintensity rim sign between the two patients groups (p<0.0001). On quantitative analysis using imaging standardization and plot-profile analysis, hyperintensity rim sign was observed in one-third of T1 low intensity MS plaques. This finding seems to be useful to differentiate multiple sclerosis from lacunar infarction. (author)

  4. Cerebral Fat Embolism: Diffusion-weighted Magnetic Resonance Imaging Findings

    International Nuclear Information System (INIS)

    Ryu, C.W.

    2005-01-01

    PURPOSE: To demonstrate the diffusion-weighted (DWI) magnetic resonance imaging (MRI) findings, and the follow-up MRI findings, of cerebral fat embolism in the acute stage. MATERIAL AND METHODS: The initial DWI and clinical findings of six patients with cerebral fat embolism were retrospectively evaluated. The finding of DWI with a b-value of 1000 s/mm 2 (b=1000) was compared with that of DWI with a b-value of 0 s/mm 2 (b=0). In three patients who underwent follow-up MRI, the interval change of the lesion on T2-weighted images was investigated. RESULTS: The characteristic DWI finding of cerebral fat embolism in the acute stage was multiple, hyperintense, dot-like lesions disseminated in the brain. These lesions were distributed dominantly in the bilateral border-zone areas. Some lesions had an ancillary location including the cortex, deep white matter, basal ganglia, and cerebellum. The lesions were more intense and numerous in DWI (b=1000) than in DWI (b=0). The findings on the follow-up T2-weighted images were multiple confluent hyperintense lesions in the white matter with progression since the initial MRI. CONCLUSION: DWI could be a sensitive tool for detecting cerebral fat embolism in the acute phase. It is recommended that DWI be included in the initial evaluation of cerebral fat embolism with MRI

  5. Heterogeneity in age-related white matter changes

    NARCIS (Netherlands)

    Schmidt, R.; Schmidt, H.; Haybaeck, J.; Loitfelder, M.; Weis, S.; Cavalieri, M.; Seiler, S.; Enzinger, C.; Ropele, S.; Erkinjuntti, T.; Pantoni, L.; Scheltens, P.; Fazekas, F.; Jellinger, K.

    2011-01-01

    White matter changes occur endemically in routine magnetic resonance imaging (MRI) scans of elderly persons. MRI appearance and histopathological correlates of white matter changes are heterogeneous. Smooth periventricular hyperintensities, including caps around the ventricular horns,

  6. Relationship between orthostatic hypotension and white matter hyperintensity load in older patients with mild dementia.

    Directory of Open Access Journals (Sweden)

    Hogne Soennesyn

    Full Text Available BACKGROUND/OBJECTIVES: White matter hyperintensities (WMH in magnetic resonance imaging (MRI scans of the brain, and orthostatic hypotension (OH are both common in older people. We tested the hypothesis that OH is associated with WMH. DESIGN: Cross-sectional study. SETTING: Secondary care outpatient clinics in geriatric medicine and old age psychiatry in western Norway. PARTICIPANTS: 160 older patients with mild dementia, diagnosed according to standardised criteria. MEASUREMENTS: OH was diagnosed according to the consensus definition, measuring blood pressure (BP in the supine position and within 3 minutes in the standing position. MRI scans were performed according to a common protocol at three centres, and the volumes of WMH were quantified using an automated method (n=82, followed by manual editing. WMH were also quantified using the visual Scheltens scale (n=139. Multiple logistic regression analyses were applied, with highest vs. lowest WMH quartile as response. RESULTS: There were no significant correlations between WMH volumes and systolic or diastolic orthostatic BP drops, and no significant correlations between Scheltens scores of WMH and systolic or diastolic BP drops. In the multivariate analyses, only APOEε4 status remained a significant predictor for WMH using the automated method (p=0.037, OR 0.075 (0.007-0.851, whereas only age remained a significant predictor for WMH scores (p=0.019, OR 1.119 (1.018-1.230. CONCLUSION: We found no association between OH and WMH load in a sample of older patients with mild dementia.

  7. Deep white matter hyperintensities, microstructural integrity and dual task walking in older people.

    Science.gov (United States)

    Ghanavati, Tabassom; Smitt, Myriam Sillevis; Lord, Stephen R; Sachdev, Perminder; Wen, Wei; Kochan, Nicole A; Brodaty, Henry; Delbaere, Kim

    2018-01-03

    To examine neural, physiological and cognitive influences on gait speed under single and dual-task conditions. Sixty-two community-dwelling older people (aged 80.0 ± 4.2 years) participated in our study. Gait speed was assessed with a timed 20-meter walk under single and dual-task (reciting alternate letters of the alphabet) conditions. Participants also underwent tests to estimate physiological fall risk based on five measures of sensorimotor function, cognitive function across five domains, brain white matter (WM) hyperintensities and WM microstructural integrity by measuring fractional anisotropy (FA). Univariate linear regression analyses showed that global physiological and cognitive measures were associated with single (β = 0.594 and β=-0.297, respectively) and dual-task gait speed (β = 0.306 and β=-0.362, respectively). Deep WMHs were associated with dual-task gait speed only (β = 0.257). Multivariate mediational analyses showed that global and executive cognition reduced the strength of the association between deep WMHs and dual-task gait speed by 27% (β = 0.188) and 44% (β = 0.145) respectively. There was a significant linear association between single-task gait speed and mean FA values of the genu (β=-0.295) and splenium (β=-0.326) of the corpus callosum, and between dual-task gait speed and mean FA values of Superior Cerebellar Peduncle (β=-0.284), splenium of the Corpus Callosum (β=-0.286) and Cingulum (β=-0.351). Greater deep WMH volumes are associated with slower walking speed under dual-task conditions, and this relationship is mediated in part by global cognition and executive abilities specifically. Furthermore, both cerebellum and cingulum are related to dual-task walking due to their role in motor skill performance and attention, respectively.

  8. Anti-N-methyl-D-aspartate receptor encephalitis concomitant with multifocal subcortical white matter lesions on magnetic resonance imaging: a case report and review of the literature.

    Science.gov (United States)

    Wang, Rui-Jin; Chen, Bu-Dong; Qi, Dong

    2015-07-08

    Anti-N-methyl-D-aspartate receptor encephalitis is a severe autoimmune disorder characterized by severe psychiatric symptoms, seizures, decreased consciousness, autonomic dysregulation, and dyskinesias. Multifocal subcortical white matter lesions on fluid-attenuated inversion recovery and diffuse weighted images have rarely been reported in previous literature, and serial magnetic resonance imaging changes after plasma exchange have not been presented before. A previously healthy 24-year-old Chinese woman presented with acute psychiatric symptoms characterized by fear and agitation followed by decreased consciousness, dyskinesias, and seizures. Magnetic resonance imaging revealed hyperintense lesions on fluid-attenuated inversion recovery and diffuse weighted images in bilateral subcortical white matter. Cerebrospinal fluid analysis revealed a mild pleocytosis with lymphocytic predominance. Protein and glucose levels were normal. Aquaporin-4 antibodies in serum and cerebrospinal fluid were negative. Identification of anti-N-methyl-D-aspartate receptor antibodies in serum and cerebrospinal fluid confirmed the diagnosis of anti-N-methyl-D-aspartate receptor encephalitis. She was initially treated with combined intravenous immunoglobulin and methylprednisolone without improvement. Plasma exchange was then initiated with good response; the patient made a full recovery after several cycles of plasma exchange. Repeat magnetic resonance imaging performed 1 month after plasma exchange showed partial resolution of the hyperintense lesions in bilateral subcortical white matter, and follow-up magnetic resonance imaging 2 months after plasma exchange showed complete resolution. Anti-N-methyl-D-aspartate receptor encephalitis may be concomitant with multifocal subcortical white matter lesions. Such lesions may resolve after appropriate immunotherapy.

  9. Whole brain white matter changes revealed by multiple diffusion metrics in multiple sclerosis: A TBSS study

    International Nuclear Information System (INIS)

    Liu, Yaou; Duan, Yunyun; He, Yong; Yu, Chunshui; Wang, Jun; Huang, Jing; Ye, Jing; Parizel, Paul M.; Li, Kuncheng; Shu, Ni

    2012-01-01

    Objective: To investigate whole brain white matter changes in multiple sclerosis (MS) by multiple diffusion indices, we examined patients with diffusion tensor imaging and utilized tract-based spatial statistics (TBSS) method to analyze the data. Methods: Forty-one relapsing-remitting multiple sclerosis (RRMS) patients and 41 age- and gender-matched normal controls were included in this study. Diffusion weighted images were acquired by employing a single-shot echo planar imaging sequence on a 1.5 T MR scanner. Voxel-wise analyses of multiple diffusion metrics, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) were performed with TBSS. Results: The MS patients had significantly decreased FA (9.11%), increased MD (8.26%), AD (3.48%) and RD (13.17%) in their white matter skeletons compared with the controls. Through TBSS analyses, we found abnormal diffusion changes in widespread white matter regions in MS patients. Specifically, decreased FA, increased MD and increased RD were involved in whole-brain white matter, while several regions exhibited increased AD. Furthermore, white matter regions with significant correlations between the diffusion metrics and the clinical variables (the EDSS scores, disease durations and white matter lesion loads) in MS patients were identified. Conclusion: Widespread white matter abnormalities were observed in MS patients revealed by multiple diffusion metrics. The diffusion changes and correlations with clinical variables were mainly attributed to increased RD, implying the predominant role of RD in reflecting the subtle pathological changes in MS

  10. Whole brain white matter changes revealed by multiple diffusion metrics in multiple sclerosis: A TBSS study

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yaou, E-mail: asiaeurope80@gmail.com [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Duan, Yunyun, E-mail: xiaoyun81.love@163.com [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); He, Yong, E-mail: yong.h.he@gmail.com [State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing 100875 (China); Yu, Chunshui, E-mail: csyuster@gmail.com [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Wang, Jun, E-mail: jun_wang@bnu.edu.cn [State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing 100875 (China); Huang, Jing, E-mail: sainthj@126.com [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Ye, Jing, E-mail: jingye.2007@yahoo.com.cn [Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Parizel, Paul M., E-mail: paul.parizel@ua.ac.be [Department of Radiology, Antwerp University Hospital and University of Antwerp, Wilrijkstraat 10, 2650 Edegem, 8 Belgium (Belgium); Li, Kuncheng, E-mail: kunchengli55@gmail.com [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Shu, Ni, E-mail: nshu55@gmail.com [State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing 100875 (China)

    2012-10-15

    Objective: To investigate whole brain white matter changes in multiple sclerosis (MS) by multiple diffusion indices, we examined patients with diffusion tensor imaging and utilized tract-based spatial statistics (TBSS) method to analyze the data. Methods: Forty-one relapsing-remitting multiple sclerosis (RRMS) patients and 41 age- and gender-matched normal controls were included in this study. Diffusion weighted images were acquired by employing a single-shot echo planar imaging sequence on a 1.5 T MR scanner. Voxel-wise analyses of multiple diffusion metrics, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) were performed with TBSS. Results: The MS patients had significantly decreased FA (9.11%), increased MD (8.26%), AD (3.48%) and RD (13.17%) in their white matter skeletons compared with the controls. Through TBSS analyses, we found abnormal diffusion changes in widespread white matter regions in MS patients. Specifically, decreased FA, increased MD and increased RD were involved in whole-brain white matter, while several regions exhibited increased AD. Furthermore, white matter regions with significant correlations between the diffusion metrics and the clinical variables (the EDSS scores, disease durations and white matter lesion loads) in MS patients were identified. Conclusion: Widespread white matter abnormalities were observed in MS patients revealed by multiple diffusion metrics. The diffusion changes and correlations with clinical variables were mainly attributed to increased RD, implying the predominant role of RD in reflecting the subtle pathological changes in MS.

  11. Diffusion-weighted MR imaging of neuro-Behcet's disease: a case report

    International Nuclear Information System (INIS)

    Hiwatashi, Akio; Moritani, Toshio; Kinoshita, Toshibumi; Westesson, Per-Lennart; Garber, Todd

    2003-01-01

    We present a serial study of diffusion-weighted imaging (DWI) in a patient with neuro-Behcet's disease. Initial T2-weighted magnetic resonance images showed a hyperintense lesion in the brain stem. The lesion was slightly hyperintense on DWI and the apparent diffusion coefficient (ADC) was slightly increased. Ten months later, DWI showed an improvement in the abnormal signal intensity and the region of increased ADC had increased in size, especially on the left side. DWI is useful for differentiating an acute exacerbation of neuro-Behcet's disease from acute infarction. (orig.)

  12. Constraints on the Galactic Halo Dark Matter from Fermi-LAT Diffuse Measurements

    Science.gov (United States)

    Ackermann, M.; Ajello, M.; Atwood, W. B.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Blandford, R. D.; Bloom, E. D.; hide

    2012-01-01

    We have performed an analysis of the diffuse gamma-ray emission with the Fermi Large Area Telescope (LAT) in the Milky Way halo region, searching for a signal from dark matter annihilation or decay. In the absence of a robust dark matter signal, constraints are presented. We consider both gamma rays produced directly in the dark matter annihilation/decay and produced by inverse Compton scattering of the e+/e- produced in the annihilation/decay. Conservative limits are derived requiring that the dark matter signal does not exceed the observed diffuse gamma-ray emission. A second set of more stringent limits is derived based on modeling the foreground astrophysical diffuse emission using the GALPROP code. Uncertainties in the height of the diffusive cosmic-ray halo, the distribution of the cosmic-ray sources in the Galaxy, the index of the injection cosmic-ray electron spectrum, and the column density of the interstellar gas are taken into account using a profile likelihood formalism, while the parameters governing the cosmic-ray propagation have been derived from fits to local cosmic-ray data. The resulting limits impact the range of particle masses over which dark matter thermal production in the early universe is possible, and challenge the interpretation of the PAMELA/Fermi-LAT cosmic ray anomalies as the annihilation of dark matter.

  13. Pediatric cervical spine marrow T2 hyperintensity: a systematic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gefen, Ron [Cooper University Hospital, Department of Diagnostic Radiology, Candem, NJ (United States); Schweitzer, Mark E. [The Ottawa Hospital and University of Ottawa, Department of Diagnostic Imaging, Ottawa (Canada); Shabshin, Nogah [Department of Diagnostic Imaging, Chaim Sheba Medical Center, Tel-HaShomer (Israel); Hospital of University of Pennsylvania, Department of Diagnostic Imaging, Philadelphia, PA (United States)

    2011-08-15

    Hyperintense areas of vertebral bone marrow on fluid-sensitive sequences are at times seen on pediatric MRI of the cervical spine in children without suspicious clinical conditions to explain marrow pathology. Although these likely have no clinical significance they may be mistaken for pathology. The purpose of this study is to systematically evaluate the locations and patterns of marrow T2 hyperintensity in the pediatric cervical spine, with respect to age. At 1.5 T, the C2 through T3 vertebrae of 82 children aged 0-17 years without clinically suspicious marrow abnormality were retrospectively reviewed by two musculoskeletal radiologists, who were blinded to patients' age. The frequency, intensity, and location of the foci of marrow T2 hyperintensity were recorded for each vertebra on a 12-point scoring system and were correlated with the patients' age. Foci of marrow hyperintensity were seen in 46/82 (56.1%) patients and in 241/734 (32.8%) vertebrae. Foci were most common in C4 (42% of patients), C5 (45.7%), and C6 (37.8%). The foci of T2 hyperintensity were more common inferiorly (188 foci) and adjacent to the anterior cortex (123). Analysis revealed no significant correlation between age and marrow score (Spearman = -0.147, P = 0.19), but did find a trend towards increased presence of marrow T2 hyperintensity in the ages of most rapid growth, 8-14 years (81.5% of patients). Vertebral body marrow T2 hyperintensity was most common endosteally and in the mid-cervical spine with a slight peak in adolescence. We therefore believe that these pediatric cervical marrow changes may be related to rapid bone growth at the point of maximal kyphotic stress. (orig.)

  14. Differential impact of white matter hyperintensities on long-term outcomes in ischemic stroke patients with large artery atherosclerosis.

    Directory of Open Access Journals (Sweden)

    Minyoul Baik

    Full Text Available The presence of white matter hyperintensity (WMH is related to poor long-term outcomes in stroke patients. However, the long-term outcome is unknown in patients with both large artery atherosclerosis (LAA and WMH.We investigated the impact of WMH on long-term outcome in patients with LAA. Consecutive patients in a prospective stroke registry were included. Patients were followed for a median of 7.7 years (interquartile range, 5.6-9.7. The degree of WMH was assessed by Fazekas grade on fluid-attenuated inversion recovery images. Total WMH burden was calculated by summation of Fazekas scores in periventricular and deep white matter. Severe WMH was defined as total burden score ≥ 3.Among 2529 patients, 639 patients (25.3% were classified with the LAA subtype. After applying exclusion criteria, the data from 538 patients were analyzed. The mean patient age was 65.7 ± 10.3 years. Severe WMHs were found in 243 patients (45.2%. During follow-up, 200 patients (37.2% died. Cox regression analysis showed that LAA patients with severe WMH had a 1.50-fold (95% CI, 1.12-2.00, p = 0.007 higher death rate compared to those without. In the older age group (≥65 years, Cox regression revealed that patients with severe WMH had a 1.75-fold (95% CI, 1.15-2.65, p = 0.008 higher 5-year death rate, whereas the younger age group did not have this association.The degree of WMH might be a surrogate marker for long-term outcome in patients with LAA. Atherosclerotic burdens in both small and large arteries might impact long-term prognosis in ischemic stroke patients.

  15. Periodic Limb Movements and White Matter Hyperintensities in First-Ever Minor Stroke or High-Risk Transient Ischemic Attack.

    Science.gov (United States)

    Boulos, Mark I; Murray, Brian J; Muir, Ryan T; Gao, Fuqiang; Szilagyi, Gregory M; Huroy, Menal; Kiss, Alexander; Walters, Arthur S; Black, Sandra E; Lim, Andrew S; Swartz, Richard H

    2017-03-01

    Emerging evidence suggests that periodic limb movements (PLMs) may contribute to the development of cerebrovascular disease. White matter hyperintensities (WMHs), a widely accepted biomarker for cerebral small vessel disease, are associated with incident stroke and death. We evaluated the association between increased PLM indices and WMH burden in patients presenting with stroke or transient ischemic attack (TIA), while controlling for vascular risk factors and stroke severity. Thirty patients presenting within 2 weeks of a first-ever minor stroke or high-risk TIA were prospectively recruited. PLM severity was measured with polysomnography. WMH burden was quantified using the Age Related White Matter Changes (ARWMC) scale based on neuroimaging. Partial Spearman's rank-order correlations and multiple linear regression models tested the association between WMH burden and PLM severity. Greater WMH burden was correlated with elevated PLM index and stroke volume. Partial Spearman's rank-order correlations demonstrated that the relationship between WMH burden and PLM index persisted despite controlling for vascular risk factors. Multivariate linear regression models revealed that PLM index was a significant predictor of an elevated ARWMC score while controlling for age, stroke volume, stroke severity, hypertension, and apnea-hypopnea index. The quantity of PLMs was associated with WMH burden in patients with first-ever minor stroke or TIA. PLMs may be a risk factor for or marker of WMH burden, even after considering vascular risk factors and stroke severity. These results invite further investigation of PLMs as a potentially useful target to reduce WMH and stroke burden. © Sleep Research Society (SRS) 2016. All rights reserved. For permissions, please email: journals.permissions@oup.com

  16. Diffusion-tensor MR imaging of gray and white matter development during normal human brain maturation.

    Science.gov (United States)

    Mukherjee, Pratik; Miller, Jeffrey H; Shimony, Joshua S; Philip, Joseph V; Nehra, Deepika; Snyder, Abraham Z; Conturo, Thomas E; Neil, Jeffrey J; McKinstry, Robert C

    2002-10-01

    Conventional MR imaging findings of human brain development are thought to result from decreasing water content, increasing macromolecular concentration, and myelination. We use diffusion-tensor MR imaging to test theoretical models that incorporate hypotheses regarding how these maturational processes influence water diffusion in developing gray and white matter. Experimental data were derived from diffusion-tensor imaging of 167 participants, ages 31 gestational weeks to 11 postnatal years. An isotropic diffusion model was applied to the gray matter of the basal ganglia and thalamus. A model that assumes changes in the magnitude of diffusion while maintaining cylindrically symmetric anisotropy was applied to the white matter of the corpus callosum and internal capsule. Deviations of the diffusion tensor from the ideal model predictions, due to measurement noise, were estimated by using Monte Carlo simulations. Developing gray matter of the basal ganglia and developing white matter of the internal capsule and corpus callosum largely conformed to theory, with only small departures from model predictions in older children. However, data from the thalamus substantially diverged from predicted values, with progressively larger deviations from the model with increasing participant age. Changes in water diffusion during maturation of central gray and white matter structures can largely be explained by theoretical models incorporating simple assumptions regarding the influence of brain water content and myelination, although deviations from theory increase as the brain matures. Diffusion-tensor MR imaging is a powerful method for studying the process of brain development, with both scientific and clinical applications.

  17. A clinico-MRI study of extrapyramidal symptoms in multiple system atrophy; Linear hyperintensity in the outer margin of the putamen

    Energy Technology Data Exchange (ETDEWEB)

    Konagaya, Masaaki; Iida, Mitsuo [Suzuka National Hospital, Mie (Japan); Konagaya, Yoko; Honda, Hitoshi

    1993-06-01

    We studied extrapyramidal symptoms and T2-weighted MRI findings of the putamen in 20 patients with multiple system atrophy (MSA) and 25 with idiopathic Parkinson's disease. Nine of the 20 MSA patients showed extrapyramidal symptoms. We could not observe cerebellar ataxia in two of the 9 patients because of severe rigidity and skinesia. Eight of the 9 MSA patients with extrapyramidal symptoms showed linear hyperintensity in the outer margin of the putamen. This abnormal intensity was bilateral and symmetric in most patients. However, in MSA patients without extrapyramidal symptoms, only one patient showed the linear hyperintensity. We could not find such abnormal intensity in any of the patients with Parkinson's disease. On proton density MRI, the signal intensity in the lesion was higher than that in the gray matter, which leads the speculation that the hyperintensity is gliosis of the putamen or increased extracellular fluid space caused by severe shrinkage of the putamen. These characteristic MRI findings may distinguish MSA with extrapyramidal symptoms from Parkinson's disease. (J.P.N.).

  18. Tract-specific fractional anisotropy predicts cognitive outcome in a community sample of middle-aged participants with white matter lesions.

    Science.gov (United States)

    Soriano-Raya, Juan José; Miralbell, Júlia; López-Cancio, Elena; Bargalló, Núria; Arenillas, Juan Francisco; Barrios, Maite; Cáceres, Cynthia; Toran, Pere; Alzamora, Maite; Dávalos, Antoni; Mataró, Maria

    2014-05-01

    Cerebral white matter lesions (WMLs) have been consistently related to cognitive dysfunction but the role of white matter (WM) damage in cognitive impairment is not fully determined. Diffusion tensor imaging is a promising tool to explain impaired cognition related to WMLs. We investigated the separate association of high-grade periventricular hyperintensities (PVHs) and deep white matter hyperintensities (DWMHs) with fractional anisotropy (FA) in middle-aged individuals. We also assessed the predictive value to cognition of FA within specific WM tracts associated with high-grade WMLs. One hundred participants from the Barcelona-AsIA Neuropsychology Study were divided into groups based on low- and high-grade WMLs. Voxel-by-voxel FA were compared between groups, with separate analyses for high-grade PVHs and DWMHs. The mean FA within areas showing differences between groups was extracted in each tract for linear regression analyses. Participants with high-grade PVHs and participants with high-grade DWMHs showed lower FA in different areas of specific tracts. Areas showing decreased FA in high-grade DWMHs predicted lower cognition, whereas areas with decreased FA in high-grade PVHs did not. The predictive value to cognition of specific WM tracts supports the involvement of cortico-subcortical circuits in cognitive deficits only in DWMHs.

  19. Brain involvement in patients with inflammatory bowel disease: a voxel-based morphometry and diffusion tensor imaging study.

    Science.gov (United States)

    Zikou, Anastasia K; Kosmidou, Maria; Astrakas, Loukas G; Tzarouchi, Loukia C; Tsianos, Epameinondas; Argyropoulou, Maria I

    2014-10-01

    To investigate structural brain changes in inflammatory bowel disease (IBD). Brain magnetic resonance imaging (MRI) was performed on 18 IBD patients (aged 45.16 ± 14.71 years) and 20 aged-matched control subjects. The imaging protocol consisted of a sagittal-FLAIR, a T1-weighted high-resolution three-dimensional spoiled gradient-echo sequence, and a multisession spin-echo echo-planar diffusion-weighted sequence. Differences between patients and controls in brain volume and diffusion indices were evaluated using the voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) methods, respectively. The presence of white-matter hyperintensities (WMHIs) was evaluated on FLAIR images. VBM revealed decreased grey matter (GM) volume in patients in the fusiform and the inferior temporal gyrus bilaterally, the right precentral gyrus, the right supplementary motor area, the right middle frontal gyrus and the left superior parietal gyrus (p tensor imaging detects microstructural brain abnormalities in IBD. • Voxel based morphometry reveals brain atrophy in IBD.

  20. White matter microstructure in transsexuals and controls investigated by diffusion tensor imaging.

    Science.gov (United States)

    Kranz, Georg S; Hahn, Andreas; Kaufmann, Ulrike; Küblböck, Martin; Hummer, Allan; Ganger, Sebastian; Seiger, Rene; Winkler, Dietmar; Swaab, Dick F; Windischberger, Christian; Kasper, Siegfried; Lanzenberger, Rupert

    2014-11-12

    Biological causes underpinning the well known gender dimorphisms in human behavior, cognition, and emotion have received increased attention in recent years. The advent of diffusion-weighted magnetic resonance imaging has permitted the investigation of the white matter microstructure in unprecedented detail. Here, we aimed to study the potential influences of biological sex, gender identity, sex hormones, and sexual orientation on white matter microstructure by investigating transsexuals and healthy controls using diffusion tensor imaging (DTI). Twenty-three female-to-male (FtM) and 21 male-to-female (MtF) transsexuals, as well as 23 female (FC) and 22 male (MC) controls underwent DTI at 3 tesla. Fractional anisotropy, axial, radial, and mean diffusivity were calculated using tract-based spatial statistics (TBSS) and fiber tractography. Results showed widespread significant differences in mean diffusivity between groups in almost all white matter tracts. FCs had highest mean diffusivities, followed by FtM transsexuals with lower values, MtF transsexuals with further reduced values, and MCs with lowest values. Investigating axial and radial diffusivities showed that a transition in axial diffusivity accounted for mean diffusivity results. No significant differences in fractional anisotropy maps were found between groups. Plasma testosterone levels were strongly correlated with mean, axial, and radial diffusivities. However, controlling for individual estradiol, testosterone, or progesterone plasma levels or for subjects' sexual orientation did not change group differences. Our data harmonize with the hypothesis that fiber tract development is influenced by the hormonal environment during late prenatal and early postnatal brain development. Copyright © 2014 the authors 0270-6474/14/3415466-10$15.00/0.

  1. White Matter Microstructure in Transsexuals and Controls Investigated by Diffusion Tensor Imaging

    Science.gov (United States)

    Kranz, Georg S.; Hahn, Andreas; Kaufmann, Ulrike; Küblböck, Martin; Hummer, Allan; Ganger, Sebastian; Seiger, Rene; Winkler, Dietmar; Swaab, Dick F.; Windischberger, Christian; Kasper, Siegfried; Lanzenberger, Rupert

    2015-01-01

    Biological causes underpinning the well known gender dimorphisms in human behavior, cognition, and emotion have received increased attention in recent years. The advent of diffusion-weighted magnetic resonance imaging has permitted the investigation of the white matter microstructure in unprecedented detail. Here, we aimed to study the potential influences of biological sex, gender identity, sex hormones, and sexual orientation on white matter microstructure by investigating transsexuals and healthy controls using diffusion tensor imaging (DTI). Twenty-three female-to-male (FtM) and 21 male-to-female (MtF) transsexuals, as well as 23 female (FC) and 22 male (MC) controls underwent DTI at 3 tesla. Fractional anisotropy, axial, radial, and mean diffusivity were calculated using tract-based spatial statistics (TBSS) and fiber tractography. Results showed widespread significant differences in mean diffusivity between groups in almost all white matter tracts. FCs had highest mean diffusivities, followed by FtM transsexuals with lower values, MtF transsexuals with further reduced values, and MCs with lowest values. Investigating axial and radial diffusivities showed that a transition in axial diffusivity accounted for mean diffusivity results. No significant differences in fractional anisotropy maps were found between groups. Plasma testosterone levels were strongly correlated with mean, axial, and radial diffusivities. However, controlling for individual estradiol, testosterone, or progesterone plasma levels or for subjects’ sexual orientation did not change group differences. Our data harmonize with the hypothesis that fiber tract development is influenced by the hormonal environment during late prenatal and early postnatal brain development. PMID:25392513

  2. An autopsied case of MM1 + MM2-cortical with thalamic-type sporadic Creutzfeldt-Jakob disease presenting with hyperintensities on diffusion-weighted MRI before clinical onset.

    Science.gov (United States)

    Iwasaki, Yasushi; Mori, Keiko; Ito, Masumi; Mimuro, Maya; Kitamoto, Tetsuyuki; Yoshida, Mari

    2017-02-01

    A 78-year-old Japanese man presented with rapidly progressive dementia and gait disturbances. Eight months before the onset of clinical symptoms, diffusion-weighted magnetic resonance imaging (DWI) demonstrated hyperintensities in the right temporal, right parietal and left medial occipital cortices. Two weeks after symptom onset, DWI showed extensive hyperintensity in the bilateral cerebral cortex, with regions of higher brightness that existed prior to symptom onset still present. Four weeks after clinical onset, periodic sharp wave complexes were identified on an electroencephalogram. Myoclonus was observed 8 weeks after clinical onset. The patient reached an akinetic mutism state and died 5 months after onset. Neuropathological examination showed widespread cerebral neocortical involvement of fine vacuole-type spongiform changes with large confluent vacuole-type spongiform changes. Spongiform degeneration with neuron loss and hypertrophic astrocytosis was also observed in the striatum and medial thalamus. The inferior olivary nucleus showed severe neuron loss with hypertrophic astrocytosis. Prion protein (PrP) immunostaining showed widespread synaptic-type PrP deposition with perivacuolar-type PrP deposition in the cerebral neocortex. Mild to moderate PrP deposition was also observed extensively in the basal ganglia, thalamus, cerebellum and brainstem, but it was not apparent in the inferior olivary nucleus. PrP gene analysis showed no mutations, and polymorphic codon 129 showed methionine homozygosity. Western blot analysis of protease-resistant PrP showed both type 1 scrapie type PrP (PrP Sc ) and type 2 PrP Sc . Based on the relationship between the neuroimaging and pathological findings, we speculated that cerebral cortical lesions with large confluent vacuoles and type 2 PrP Sc would show higher brightness and continuous hyperintensity on DWI than those with fine vacuoles and type 1 PrP Sc . We believe the present patient had a combined form of MM1

  3. High b-value diffusion-weighted imaging in progressive multifocal leukoencephalopathy in HIV patients

    International Nuclear Information System (INIS)

    Godi, Claudia; De Vita, Enrico; Davagnanam, Indran; Tombetti, Enrico; Haddow, Lewis; Jaeger, Hans Rolf

    2017-01-01

    An ill-defined hyperintense edge and hypointense core on diffusion-weighted imaging (DWI) is typical of progressive multifocal leukoencephalopathy (PML). We aimed to investigate whether a b-value of 3,000 s/mm"2 (b3000) can improve visualisation of PML, or provide different structural information compared to 1,000 s/mm"2 (b1000). We retrospectively identified HIV-positive patients with confirmed PML studied under a clinical protocol including both b1000 and b3000 DWI. The rim and core of each PML lesion and normal-appearing white matter (NAWM) were outlined on trace-weighted DWI. Signal intensities, apparent diffusion coefficient (ADC) values and volumes were measured and compared between b1000 and b3000. Nine lesions from seven patients were analysed. The rim and core were better visualised on b3000, with higher signal of the rim and lower signal of the core compared to NAWM. The hyperintense rim had non-restricted average ADCs, but included foci of low ADC on both b3000 and b1000. Despite similar total lesion volumes, b3000 displayed significantly larger core and smaller rim volumes than b1000. b3000 improves visualisation of this important PML hallmark. Moreover, b3000 partly reclassifies tissue from rim into core, and might provide potentially more accurate biomarkers of PML activity and prognosis. (orig.)

  4. High b-value diffusion-weighted imaging in progressive multifocal leukoencephalopathy in HIV patients

    Energy Technology Data Exchange (ETDEWEB)

    Godi, Claudia [San Raffaele Scientific Institute, Neuroradiology Department, Milan (Italy); The National Hospital for Neurology and Neurosurgery, Lysholm Department of Neuroradiology, London (United Kingdom); UCL Institute of Neurology, Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, London (United Kingdom); De Vita, Enrico; Davagnanam, Indran [The National Hospital for Neurology and Neurosurgery, Lysholm Department of Neuroradiology, London (United Kingdom); UCL Institute of Neurology, Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, London (United Kingdom); Tombetti, Enrico [Vita-Salute San Raffaele University, Milan (Italy); Haddow, Lewis [University College London, Centre for Sexual Health and HIV Research, Research Department of Infection and Population Health, London (United Kingdom); Jaeger, Hans Rolf [The National Hospital for Neurology and Neurosurgery, Lysholm Department of Neuroradiology, London (United Kingdom); UCL Institute of Neurology, Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, London (United Kingdom); University College Hospital, Centre of Medical Imaging, London (United Kingdom)

    2017-09-15

    An ill-defined hyperintense edge and hypointense core on diffusion-weighted imaging (DWI) is typical of progressive multifocal leukoencephalopathy (PML). We aimed to investigate whether a b-value of 3,000 s/mm{sup 2} (b3000) can improve visualisation of PML, or provide different structural information compared to 1,000 s/mm{sup 2} (b1000). We retrospectively identified HIV-positive patients with confirmed PML studied under a clinical protocol including both b1000 and b3000 DWI. The rim and core of each PML lesion and normal-appearing white matter (NAWM) were outlined on trace-weighted DWI. Signal intensities, apparent diffusion coefficient (ADC) values and volumes were measured and compared between b1000 and b3000. Nine lesions from seven patients were analysed. The rim and core were better visualised on b3000, with higher signal of the rim and lower signal of the core compared to NAWM. The hyperintense rim had non-restricted average ADCs, but included foci of low ADC on both b3000 and b1000. Despite similar total lesion volumes, b3000 displayed significantly larger core and smaller rim volumes than b1000. b3000 improves visualisation of this important PML hallmark. Moreover, b3000 partly reclassifies tissue from rim into core, and might provide potentially more accurate biomarkers of PML activity and prognosis. (orig.)

  5. Brain involvement in patients with inflammatory bowel disease: a voxel-based morphometry and diffusion tensor imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Zikou, Anastasia K.; Astrakas, Loukas G.; Tzarouchi, Loukia C.; Argyropoulou, Maria I. [University of Ioannina, Department of Radiology, Medical School, Ioannina (Greece); Kosmidou, Maria; Tsianos, Epameinondas [University of Ioannina, 1st Department of Internal Medicine (Hepato-Gastroenterology Unit), Medical School, Ioannina (Greece)

    2014-10-15

    To investigate structural brain changes in inflammatory bowel disease (IBD). Brain magnetic resonance imaging (MRI) was performed on 18 IBD patients (aged 45.16 ± 14.71 years) and 20 aged-matched control subjects. The imaging protocol consisted of a sagittal-FLAIR, a T1-weighted high-resolution three-dimensional spoiled gradient-echo sequence, and a multisession spin-echo echo-planar diffusion-weighted sequence. Differences between patients and controls in brain volume and diffusion indices were evaluated using the voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) methods, respectively. The presence of white-matter hyperintensities (WMHIs) was evaluated on FLAIR images. VBM revealed decreased grey matter (GM) volume in patients in the fusiform and the inferior temporal gyrus bilaterally, the right precentral gyrus, the right supplementary motor area, the right middle frontal gyrus and the left superior parietal gyrus (p < 0.05). TBSS showed decreased axial diffusivity (AD) in the right corticospinal tract and the right superior longitudinal fasciculus in patients compared with controls. A larger number of WMHIs was observed in patients (p < 0.05). Patients with IBD show an increase in WMHIs and GM atrophy, probably related to cerebral vasculitis and ischaemia. Decreased AD in major white matter tracts could be a secondary phenomenon, representing Wallerian degeneration. (orig.)

  6. Brain involvement in patients with inflammatory bowel disease: a voxel-based morphometry and diffusion tensor imaging study

    International Nuclear Information System (INIS)

    Zikou, Anastasia K.; Astrakas, Loukas G.; Tzarouchi, Loukia C.; Argyropoulou, Maria I.; Kosmidou, Maria; Tsianos, Epameinondas

    2014-01-01

    To investigate structural brain changes in inflammatory bowel disease (IBD). Brain magnetic resonance imaging (MRI) was performed on 18 IBD patients (aged 45.16 ± 14.71 years) and 20 aged-matched control subjects. The imaging protocol consisted of a sagittal-FLAIR, a T1-weighted high-resolution three-dimensional spoiled gradient-echo sequence, and a multisession spin-echo echo-planar diffusion-weighted sequence. Differences between patients and controls in brain volume and diffusion indices were evaluated using the voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) methods, respectively. The presence of white-matter hyperintensities (WMHIs) was evaluated on FLAIR images. VBM revealed decreased grey matter (GM) volume in patients in the fusiform and the inferior temporal gyrus bilaterally, the right precentral gyrus, the right supplementary motor area, the right middle frontal gyrus and the left superior parietal gyrus (p < 0.05). TBSS showed decreased axial diffusivity (AD) in the right corticospinal tract and the right superior longitudinal fasciculus in patients compared with controls. A larger number of WMHIs was observed in patients (p < 0.05). Patients with IBD show an increase in WMHIs and GM atrophy, probably related to cerebral vasculitis and ischaemia. Decreased AD in major white matter tracts could be a secondary phenomenon, representing Wallerian degeneration. (orig.)

  7. Charge diffusion and the butterfly effect in striped holographic matter

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, Andrew [Department of Physics, Harvard University,Cambridge, MA 02138 (United States); Department of Physics, Stanford University,Stanford, CA 94305 (United States); Steinberg, Julia [Department of Physics, Harvard University,Cambridge, MA 02138 (United States)

    2016-10-26

    Recently, it has been proposed that the butterfly velocity — a speed at which quantum information propagates — may provide a fundamental bound on diffusion constants in dirty incoherent metals. We analytically compute the charge diffusion constant and the butterfly velocity in charge-neutral holographic matter with long wavelength “hydrodynamic' disorder in a single spatial direction. In this limit, we find that the butterfly velocity does not set a sharp lower bound for the charge diffusion constant.

  8. Charge diffusion and the butterfly effect in striped holographic matter

    International Nuclear Information System (INIS)

    Lucas, Andrew; Steinberg, Julia

    2016-01-01

    Recently, it has been proposed that the butterfly velocity — a speed at which quantum information propagates — may provide a fundamental bound on diffusion constants in dirty incoherent metals. We analytically compute the charge diffusion constant and the butterfly velocity in charge-neutral holographic matter with long wavelength “hydrodynamic' disorder in a single spatial direction. In this limit, we find that the butterfly velocity does not set a sharp lower bound for the charge diffusion constant.

  9. Association between Low-density lipoprotein cholesterol and occipital periventricular hyperintensities in a group of Chinese patients: an observational study.

    Science.gov (United States)

    Duan, Dazhi; Shen, Lin; Cui, Chun; Shu, Tongsheng; Zheng, Jian

    2017-02-27

    While occipital periventricular hyperintensities (OPVHs) are among the most common mild white matter hyperintensities, the clinical factors associated with OPVHs remain unclear. In this study, we investigated the role of clinical factors in development of pure OPVHs. This study included 97 patients with OPVHs and 73 healthy controls. Univariate analysis of clinical factors in OPVH patients and controls was followed by binomial logistic regression analysis to identify clinical factors significantly associated with OPVHs. Univariate analysis indicated that age, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and apolipoprotein-B (Apo-B) levels differed significantly between the OPVH patients and controls (p correlated with OPVH scores (p anti-correlated with OPVHs scores (p correlated with OPVHs (p correlated with OPVHs (p < 0.001). In summary, LDL-C was negatively and age was positively associated with OPVHs among Chinese patients in a hospital.

  10. The correlation between white matter hyperintensity and balance disorder and fall risk: An observational, prospective cohort study.

    Science.gov (United States)

    Shen, Dong-Chao; Wu, Shuo-Lin; Shi, Yu-Zhi; Wang, Shuo; Zhang, Yu-Mei; Wang, Chun-Xue

    2016-09-01

    The presence of an association between white matter hyperintensity (WMH) and the risk of falls in older people is uncertain, with little supporting prospective evidence available at present. We aimed to determine whether WMH was associated with dysfunctions of balance and gait, and other sensorimotor factors leading to falls, and the independent factors related to falls in older Chinese people. The protective effect of exercise against falls was also addressed. In a representative sample of hospital-based individuals aged 50 years and older in China, the patients' history of falls, magnetic resonance imaging data, scores on the 9-item Berg Balance Scale (BBS-9) test and timed up-and-go test (TUGT), and sensorimotor measures of computerized dynamic posturography (CDP) were analyzed. Incident falls were recorded prospectively over a 12-month period. Using regression modeling, the association between the risk of falls and baseline WMH was estimated. Only individuals with severe WMH were at an increased risk of falls, and CDP was more sensitive than BBS-9 in detecting WMH-related balance and gait dysfunction. However, WMH was not an independent predictor of falls. Taller height and overweight or obese body habitus were identified as novel protective factors for falls. Female, fall history, and increased TUGT score were identified as independent risk factors for falls in older Chinese people. Although WMH was associated with an increased risk of falls, it was not an independent predictor.

  11. Diffusion constant in hot and dense hadronic matter. A hadro-molecular-dynamic calculation

    International Nuclear Information System (INIS)

    Sasaki, N.; Miyamura, O.; Muroya, S.; Nonaka, C.

    2002-01-01

    We evaluate baryon/charge diffusion constant of dense and hot hadronic matter based on the molecular dynamical method by using a hadronic collision generator which describes nuclear collisions at energies 10 1-2 GeV/A and satisfies detailed balance at low temperatures (T ≤ 200 MeV). For the hot and dense hadronic matter of the temperature range, T = 100 - 200 MeV and baryon number density, n B =0.16 fm -3 - 0.32 fm -3 , charge diffusion constant D gradually increases from 0.5 fmc to 2 fmc with temperature and is almost independent of baryon number density. Based on the obtained diffusion constant we make simple discussions on the diffusion of charge fluctuation in ultrarelativistic nuclear collisions. (author)

  12. Diffusion Weighted MRI as a predictive tool for effect of radiotherapy in locally advanced cervical cancer

    DEFF Research Database (Denmark)

    Haack, Søren; Tanderup, Kari; Fokdal, Lars

    Diffusion weighted MRI has shown great potential in diagnostic cancer imaging and may also have value for monitoring tumor response during radiotherapy. Patients with advanced cervical cancer are treated with external beam radiotherapy followed by brachytherapy. This study evaluates the value of DW......-MRI for predicting outcome of patients with advanced cervical cancer at time of brachytherapy. Volume of hyper-intensity on highly diffusion sensitive images and resulting ADC value for treatment responders and non-responders is compared. The change of ADC and volume of hyper-intensity over time of BT is also...

  13. White matter hyperintensities are seen only in GRN mutation carriers in the GENFI cohort

    Directory of Open Access Journals (Sweden)

    Carole H. Sudre

    2017-01-01

    Full Text Available Genetic frontotemporal dementia is most commonly caused by mutations in the progranulin (GRN, microtubule-associated protein tau (MAPT and chromosome 9 open reading frame 72 (C9orf72 genes. Previous small studies have reported the presence of cerebral white matter hyperintensities (WMH in genetic FTD but this has not been systematically studied across the different mutations. In this study WMH were assessed in 180 participants from the Genetic FTD Initiative (GENFI with 3D T1- and T2-weighed magnetic resonance images: 43 symptomatic (7 GRN, 13 MAPT and 23 C9orf72, 61 presymptomatic mutation carriers (25 GRN, 8 MAPT and 28 C9orf72 and 76 mutation negative non-carrier family members. An automatic detection and quantification algorithm was developed for determining load, location and appearance of WMH. Significant differences were seen only in the symptomatic GRN group compared with the other groups with no differences in the MAPT or C9orf72 groups: increased global load of WMH was seen, with WMH located in the frontal and occipital lobes more so than the parietal lobes, and nearer to the ventricles rather than juxtacortical. Although no differences were seen in the presymptomatic group as a whole, in the GRN cohort only there was an association of increased WMH volume with expected years from symptom onset. The appearance of the WMH was also different in the GRN group compared with the other groups, with the lesions in the GRN group being more similar to each other. The presence of WMH in those with progranulin deficiency may be related to the known role of progranulin in neuroinflammation, although other roles are also proposed including an effect on blood-brain barrier permeability and the cerebral vasculature. Future studies will be useful to investigate the longitudinal evolution of WMH and their potential use as a biomarker as well as post-mortem studies investigating the histopathological nature of the lesions.

  14. Diffusion weighted MR imaging of acute Wernicke's encephalopathy

    International Nuclear Information System (INIS)

    Chung, Tae-Ick; Kim, Joong-Seok; Park, Soung-Kyeong; Kim, Beum-Saeng; Ahn, Kook-Jin; Yang, Dong-Won

    2003-01-01

    We report a case of Wernicke's encephalopathy in which diffusion-weighted MR images demonstrated symmetrical hyperintense lesions in the paraventricular area of the third ventricles and medial thalami. Apparent diffusion coefficient mapping showed isointensity in the aforementioned areas. Diffusion-weighted MR images may provide evidence of vasogenic edema associated with thiamine deficiency, proven in the histopathology of experimental animals. In addition, diffusion-weighted MRI has many advantages over T2 or FLARE-weighted brain MRI in detecting structural and functional abnormalities in Wernicke's encephalopathy

  15. Exploring the multiple-hit hypothesis of preterm white matter damage using diffusion MRI

    Directory of Open Access Journals (Sweden)

    Madeleine L. Barnett

    2018-01-01

    Conclusion: This study suggests multiple perinatal risk factors have an independent association with diffuse white matter injury at term equivalent age and exposure to multiple perinatal risk factors exacerbates dMRI defined, clinically significant white matter injury. Our findings support the multiple hit hypothesis for preterm white matter injury.

  16. Anatomical and diffusion MRI of deep gray matter in pediatric spina bifida

    Directory of Open Access Journals (Sweden)

    Ashley L. Ware

    2014-01-01

    Full Text Available Individuals with spina bifida myelomeningocele (SBM exhibit brain abnormalities in cortical thickness, white matter integrity, and cerebellar structure. Little is known about deep gray matter macro- and microstructure in this population. The current study utilized volumetric and diffusion-weighted MRI techniques to examine gray matter volume and microstructure in several subcortical structures: basal ganglia nuclei, thalamus, hippocampus, and amygdala. Sixty-six children and adolescents (ages 8–18; M = 12.0, SD = 2.73 with SBM and typically developing (TD controls underwent T1- and diffusion-weighted neuroimaging. Microstructural results indicated that hippocampal volume was disproportionately reduced, whereas the putamen volume was enlarged in the group with SBM. Microstructural analyses indicated increased mean diffusivity (MD and fractional anisotropy (FA in the gray matter of most examined structures (i.e., thalamus, caudate, hippocampus, with the putamen exhibiting a unique pattern of decreased MD and increased FA. These results provide further support that SBM differentially disrupts brain regions whereby some structures are volumetrically normal whereas others are reduced or enlarged. In the hippocampus, volumetric reduction coupled with increased MD may imply reduced cellular density and aberrant organization. Alternatively, the enlarged volume and significantly reduced MD in the putamen suggest increased density.

  17. Regional diffusion changes of cerebral grey matter during normal aging-A fluid-inversion prepared diffusion imaging study

    International Nuclear Information System (INIS)

    Ni Jianming; Chen Shuang; Liu Jianjun; Huang Gang; Shen Tianzhen; Chen Xingrong

    2010-01-01

    Background and purpose: Although diffusion characteristics of white matter (WM) and its aging effects have been well described in the literature, diffusion characteristics of grey matter (GM), especially the cortical GM, have not been fully evaluated. In the present study, we used the fluid-inversion prepared diffusion imaging (FLIPD) technique to determine if there are age-related water diffusivity changes in GM. Materials and methods: 120 healthy volunteers were recruited for our study. They were divided into three age groups: group one (20-39 years old), group two (40-59 years old) and group three (60 years or older). All patients were evaluated with MRI using FLIPD at 3.0 T. Apparent diffusion coefficient (ADC) values of the frontal GM, cingulate cortex and thalami were determined bilaterally by region-of-interest analysis. Results: Group three had significantly higher ADC values in both thalami and the left frontal GM compared to group two or group one. No ADC value difference was found among the three groups in the right frontal GM and bilateral cingulate cortex. There was a significant positive correlation between individual ADC values and age in both thalami and left frontal GM. For the cingulate cortex and the right frontal GM, ADC values did not correlate significantly with advancing age. Conclusion: Statistically significant age-related diffusion changes were observed in both thalami and the left frontal cortex. The data reported here may serve as a reference for future studies.

  18. Revealing dark matter substructure with anisotropies in the diffuse gamma-ray background

    International Nuclear Information System (INIS)

    Siegal-Gaskins, Jennifer M

    2008-01-01

    The majority of gamma-ray emission from galactic dark matter annihilation is likely to be detected as a contribution to the diffuse gamma-ray background. I show that dark matter substructure in the halo of the Galaxy induces characteristic anisotropies in the diffuse background that could be used to determine the small-scale dark matter distribution. I calculate the angular power spectrum of the emission from dark matter substructure for several models of the subhalo population and show that features in the power spectrum can be used to infer the presence of substructure. The shape of the power spectrum is largely unaffected by the subhalo radial distribution and mass function, and for many scenarios I find that a measurement of the angular power spectrum by Fermi will be able to constrain the abundance of substructure. An anti-biased subhalo radial distribution is shown to produce emission that differs significantly in intensity and large-scale angular dependence from that of a subhalo distribution which traces the smooth dark matter halo, potentially impacting the detectability of the dark matter signal for a variety of targets and methods

  19. Revealing dark matter substructure with anisotropies in the diffuse gamma-ray background

    Energy Technology Data Exchange (ETDEWEB)

    Siegal-Gaskins, Jennifer M, E-mail: jsg@kicp.uchicago.edu [Kavli Institute for Cosmological Physics and Department of Physics, University of Chicago, 5640 S. Ellis Avenue, Chicago, IL 60637 (United States)

    2008-10-15

    The majority of gamma-ray emission from galactic dark matter annihilation is likely to be detected as a contribution to the diffuse gamma-ray background. I show that dark matter substructure in the halo of the Galaxy induces characteristic anisotropies in the diffuse background that could be used to determine the small-scale dark matter distribution. I calculate the angular power spectrum of the emission from dark matter substructure for several models of the subhalo population and show that features in the power spectrum can be used to infer the presence of substructure. The shape of the power spectrum is largely unaffected by the subhalo radial distribution and mass function, and for many scenarios I find that a measurement of the angular power spectrum by Fermi will be able to constrain the abundance of substructure. An anti-biased subhalo radial distribution is shown to produce emission that differs significantly in intensity and large-scale angular dependence from that of a subhalo distribution which traces the smooth dark matter halo, potentially impacting the detectability of the dark matter signal for a variety of targets and methods.

  20. Differential Effect of Left vs. Right White Matter Hyperintensity Burden on Functional Decline: The Northern Manhattan Study.

    Science.gov (United States)

    Dhamoon, Mandip S; Cheung, Ying-Kuen; Bagci, Ahmet; Alperin, Noam; Sacco, Ralph L; Elkind, Mitchell S V; Wright, Clinton B

    2017-01-01

    Asymmetry of brain dysfunction may disrupt brain network efficiency. We hypothesized that greater left-right white matter hyperintensity volume (WMHV) asymmetry was associated with functional trajectories. Methods: In the Northern Manhattan Study, participants underwent brain MRI with axial T1, T2, and fluid attenuated inversion recovery sequences, with baseline interview and examination. Volumetric WMHV distribution across 14 brain regions was determined separately by combining bimodal image intensity distribution and atlas based methods. Participants had annual functional assessments with the Barthel index (BI, range 0-100) over a mean of 7.3 years. Generalized estimating equations (GEE) models estimated associations of regional WMHV and regional left-right asymmetry with baseline BI and change over time, adjusted for baseline medical risk factors, sociodemographics, and cognition, and stroke and myocardial infarction during follow-up. Results: Among 1,195 participants, greater WMHV asymmetry in the parietal lobes (-8.46 BI points per unit greater WMHV on the right compared to left, 95% CI -3.07, -13.86) and temporal lobes (-2.48 BI points, 95% CI -1.04, -3.93) was associated with lower overall function. Greater WMHV asymmetry in the parietal lobes (-1.09 additional BI points per year per unit greater WMHV on the left compared to right, 95% CI -1.89, -0.28) was independently associated with accelerated functional decline. Conclusions: In this large population-based study with long-term repeated measures of function, greater regional WMHV asymmetry was associated with lower function and functional decline. In addition to global WMHV, WHMV asymmetry may be an important predictor of long-term functional status.

  1. Application of variable threshold intensity to segmentation for white matter hyperintensities in fluid attenuated inversion recovery magnetic resonance images

    International Nuclear Information System (INIS)

    Yoo, Byung Il; Han, Ji Won; Oh, San Yeo Wool; Kim, Tae Hui; Lee, Jung Jae; Lee, Eun Young; MacFall, James R.; Payne, Martha E.; Kim, Jae Hyoung; Kim, Ki Woong

    2014-01-01

    White matter hyperintensities (WMHs) are regions of abnormally high intensity on T2-weighted or fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI). Accurate and reproducible automatic segmentation of WMHs is important since WMHs are often seen in the elderly and are associated with various geriatric and psychiatric disorders. We developed a fully automated monospectral segmentation method for WMHs using FLAIR MRIs. Through this method, we introduce an optimal threshold intensity (I O ) for segmenting WMHs, which varies with WMHs volume (V WMH ), and we establish the I O -V WMH relationship. Our method showed accurate validations in volumetric and spatial agreements of automatically segmented WMHs compared with manually segmented WMHs for 32 confirmatory images. Bland-Altman values of volumetric agreement were 0.96 ± 8.311 ml (bias and 95 % confidence interval), and the similarity index of spatial agreement was 0.762 ± 0.127 (mean ± standard deviation). Furthermore, similar validation accuracies were obtained in the images acquired from different scanners. The proposed segmentation method uses only FLAIR MRIs, has the potential to be accurate with images obtained from different scanners, and can be implemented with a fully automated procedure. In our study, validation results were obtained with FLAIR MRIs from only two scanner types. The design of the method may allow its use in large multicenter studies with correct efficiency. (orig.)

  2. Application of variable threshold intensity to segmentation for white matter hyperintensities in fluid attenuated inversion recovery magnetic resonance images

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Byung Il; Han, Ji Won; Oh, San Yeo Wool; Kim, Tae Hui [Seoul National University Bundang Hospital, Department of Neuropsychiatry, Seongnam, Gyeonggi-do (Korea, Republic of); Lee, Jung Jae; Lee, Eun Young [Kyungbook National University Chilgok Hospital, Department of Psychiatry, Buk-gu, Daegu (Korea, Republic of); MacFall, James R. [Duke University Medical Center, Neuropsychiatric Imaging Research Laboratory, Durham, NC (United States); Duke University Medical Center, Department of Radiology, Durham, NC (United States); Payne, Martha E. [Duke University Medical Center, Neuropsychiatric Imaging Research Laboratory, Durham, NC (United States); Duke University Medical Center, Department of Psychiatry and Behavioral Sciences, Durham, NC (United States); Kim, Jae Hyoung [Seoul National University Bundang Hospital, Department of Radiology, Seongnam, Gyeonggi-do (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, Jongno-gu, Seoul (Korea, Republic of); Kim, Ki Woong [Seoul National University Bundang Hospital, Department of Neuropsychiatry, Seongnam, Gyeonggi-do (Korea, Republic of); Seoul National University College of Medicine, Department of Psychiatry, Jongno-gu, Seoul (Korea, Republic of); Seoul National University College of Natural Sciences, Department of Brain and Cognitive Science, Gwanak-gu, Seoul (Korea, Republic of)

    2014-04-15

    White matter hyperintensities (WMHs) are regions of abnormally high intensity on T2-weighted or fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI). Accurate and reproducible automatic segmentation of WMHs is important since WMHs are often seen in the elderly and are associated with various geriatric and psychiatric disorders. We developed a fully automated monospectral segmentation method for WMHs using FLAIR MRIs. Through this method, we introduce an optimal threshold intensity (I{sub O}) for segmenting WMHs, which varies with WMHs volume (V{sub WMH}), and we establish the I{sub O} -V{sub WMH} relationship. Our method showed accurate validations in volumetric and spatial agreements of automatically segmented WMHs compared with manually segmented WMHs for 32 confirmatory images. Bland-Altman values of volumetric agreement were 0.96 ± 8.311 ml (bias and 95 % confidence interval), and the similarity index of spatial agreement was 0.762 ± 0.127 (mean ± standard deviation). Furthermore, similar validation accuracies were obtained in the images acquired from different scanners. The proposed segmentation method uses only FLAIR MRIs, has the potential to be accurate with images obtained from different scanners, and can be implemented with a fully automated procedure. In our study, validation results were obtained with FLAIR MRIs from only two scanner types. The design of the method may allow its use in large multicenter studies with correct efficiency. (orig.)

  3. Characterizing the microstructural basis of "unidentified bright objects" in neurofibromatosis type 1: A combined in vivo multicomponent T2 relaxation and multi-shell diffusion MRI analysis.

    Science.gov (United States)

    Billiet, Thibo; Mädler, Burkhard; D'Arco, Felice; Peeters, Ronald; Deprez, Sabine; Plasschaert, Ellen; Leemans, Alexander; Zhang, Hui; den Bergh, Bea Van; Vandenbulcke, Mathieu; Legius, Eric; Sunaert, Stefan; Emsell, Louise

    2014-01-01

    The histopathological basis of "unidentified bright objects" (UBOs) (hyperintense regions seen on T2-weighted magnetic resonance (MR) brain scans in neurofibromatosis-1 (NF1)) remains unclear. New in vivo MRI-based techniques (multi-exponential T2 relaxation (MET2) and diffusion MR imaging (dMRI)) provide measures relating to microstructural change. We combined these methods and present previously unreported data on in vivo UBO microstructure in NF1. 3-Tesla dMRI data were acquired on 17 NF1 patients, covering 30 white matter UBOs. Diffusion tensor, kurtosis and neurite orientation and dispersion density imaging parameters were calculated within UBO sites and in contralateral normal appearing white matter (cNAWM). Analysis of MET2 parameters was performed on 24 UBO-cNAWM pairs. No significant alterations in the myelin water fraction and intra- and extracellular (IE) water fraction were found. Mean T2 time of IE water was significantly higher in UBOs. UBOs furthermore showed increased axial, radial and mean diffusivity, and decreased fractional anisotropy, mean kurtosis and neurite density index compared to cNAWM. Neurite orientation dispersion and isotropic fluid fraction were unaltered. Our results suggest that demyelination and axonal degeneration are unlikely to be present in UBOs, which appear to be mainly caused by a shift towards a higher T2-value of the intra- and extracellular water pool. This may arise from altered microstructural compartmentalization, and an increase in 'extracellular-like', intracellular water, possibly due to intramyelinic edema. These findings confirm the added value of combining dMRI and MET2 to characterize the microstructural basis of T2 hyperintensities in vivo.

  4. Subcortical White Matter Changes with Normal Aging Detected by Multi-Shot High Resolution Diffusion Tensor Imaging.

    Directory of Open Access Journals (Sweden)

    Sheng Xie

    Full Text Available Subcortical white matter builds neural connections between cortical and subcortical regions and constitutes the basis of neural networks. It plays a very important role in normal brain function. Various studies have shown that white matter deteriorates with aging. However, due to the limited spatial resolution provided by traditional diffusion imaging techniques, microstructural information from subcortical white matter with normal aging has not been comprehensively assessed. This study aims to investigate the deterioration effect with aging in the subcortical white matter and provide a baseline standard for pathological disorder diagnosis. We apply our newly developed multi-shot high resolution diffusion tensor imaging, using self-feeding multiplexed sensitivity-encoding, to measure subcortical white matter changes in regions of interest of healthy persons with a wide age range. Results show significant fractional anisotropy decline and radial diffusivity increasing with age, especially in the anterior part of the brain. We also find that subcortical white matter has more prominent changes than white matter close to the central brain. The observed changes in the subcortical white matter may be indicative of a mild demyelination and a loss of myelinated axons, which may contribute to normal age-related functional decline.

  5. Relationship between levels of serum creatinine and perirenal hyperintensity on heavily T2-weighted MR images

    Energy Technology Data Exchange (ETDEWEB)

    Erden, Ayse, E-mail: ayse.erden@medicine.ankara.edu.tr [Ankara University, School of Medicine, Department of Radiology, Talatpasa Bulvari, Sihhiye, 06100 Ankara (Turkey); Sahin, Burcu Savran, E-mail: bsavrans@hotmail.com [Ankara University, School of Medicine, Department of Radiology, Talatpasa Bulvari, Sihhiye, 06100 Ankara (Turkey); Orgodol, Horolsuren, E-mail: hoogii99@yahoo.com [Ankara University, School of Medicine, Department of Radiology, Talatpasa Bulvari, Sihhiye, 06100 Ankara (Turkey); Erden, Ilhan, E-mail: erden@medicine.ankara.edu.tr [Ankara University, School of Medicine, Department of Radiology, Talatpasa Bulvari, Sihhiye, 06100 Ankara (Turkey); Biyikli, Zeynep, E-mail: zeynep.biyikli@gmail.com [Ankara University, School of Medicine, Department of Biostatistics, Talatpasa Bulvari, Sihhiye, 06100 Ankara (Turkey)

    2011-11-15

    Objective: To determine the frequency of perirenal hyperintensity on heavily T2-weighted images and to evaluate its relationship with serum creatinine levels. Subjects and methods: Axial and coronal single-shot fast spin-echo images which have been originally obtained for MR cholangiopancreatography in 150 subjects were examined by two observers individually for the presence of perirenal hyperintensity. The morphologic properties of perirenal hyperintensity (peripheral rim-like, discontinuous, polar) were recorded. Chi square test was used to test whether the frequencies of bilateral perirenal hyperintensity differ significantly in subjects with high serum creatinine levels and those with normal creatinine levels. This test was also used to compare the frequencies of perirenal hyperintensity in patients with and without renal cysts and in patients with and without corticomedullary differentiation. A p value of less than 0.05 was considered to be statistically significant. Results: The perirenal hyperintensity was identified in 40 of 150 cases (26.6%) on heavily T2-weighted image. Serum creatinine levels were high in 18 of 150 cases (12%). The perirenal hyperintensity was present in 11 of 18 subjects (61%) with high serum creatinine levels and 26 of 132 subjects (19.7%) with normal creatinine levels. The difference of rates in two groups was statistically significant. Odds ratio was 6407 (95% confidence interval 2264-18,129). The frequency of perirenal hyperintensity was also significantly higher in subjects with renal cyst or cysts in whom serum creatinine levels were normal (p < 0.05) (37.5% vs. 11.8%). Conclusion: Perirenal hyperintensities are more frequent in patients with high serum creatinine levels. They are also more common in patients with simple renal cysts.

  6. Relationship between levels of serum creatinine and perirenal hyperintensity on heavily T2-weighted MR images

    International Nuclear Information System (INIS)

    Erden, Ayse; Sahin, Burcu Savran; Orgodol, Horolsuren; Erden, Ilhan; Biyikli, Zeynep

    2011-01-01

    Objective: To determine the frequency of perirenal hyperintensity on heavily T2-weighted images and to evaluate its relationship with serum creatinine levels. Subjects and methods: Axial and coronal single-shot fast spin-echo images which have been originally obtained for MR cholangiopancreatography in 150 subjects were examined by two observers individually for the presence of perirenal hyperintensity. The morphologic properties of perirenal hyperintensity (peripheral rim-like, discontinuous, polar) were recorded. Chi square test was used to test whether the frequencies of bilateral perirenal hyperintensity differ significantly in subjects with high serum creatinine levels and those with normal creatinine levels. This test was also used to compare the frequencies of perirenal hyperintensity in patients with and without renal cysts and in patients with and without corticomedullary differentiation. A p value of less than 0.05 was considered to be statistically significant. Results: The perirenal hyperintensity was identified in 40 of 150 cases (26.6%) on heavily T2-weighted image. Serum creatinine levels were high in 18 of 150 cases (12%). The perirenal hyperintensity was present in 11 of 18 subjects (61%) with high serum creatinine levels and 26 of 132 subjects (19.7%) with normal creatinine levels. The difference of rates in two groups was statistically significant. Odds ratio was 6407 (95% confidence interval 2264-18,129). The frequency of perirenal hyperintensity was also significantly higher in subjects with renal cyst or cysts in whom serum creatinine levels were normal (p < 0.05) (37.5% vs. 11.8%). Conclusion: Perirenal hyperintensities are more frequent in patients with high serum creatinine levels. They are also more common in patients with simple renal cysts.

  7. White matter hyperintensities and cognitive reserve during a working memory task: a functional magnetic resonance imaging study in cognitively normal older adults.

    Science.gov (United States)

    Fernández-Cabello, Sara; Valls-Pedret, Cinta; Schurz, Matthias; Vidal-Piñeiro, Dídac; Sala-Llonch, Roser; Bargallo, Nuria; Ros, Emilio; Bartrés-Faz, David

    2016-12-01

    Cognitive reserve (CR) models posit that lifestyle factors such as education modulate the relationship between brain damage and cognition. However, the functional correlates of CR in healthy aging are still under investigation. White matter hyperintensities (WMHs) are a common age-associated finding that impacts cognition. In this study, we used functional magnetic resonance imaging to characterize the patterns of brain activation during a working memory task in older participants with high and low levels of education (as a proxy of CR) and high and low WMH volumes. Ninety older volunteers (aged 63-76 years) and 16 young adults (aged 21-27) completed the study. We found that older adults with higher education had better working memory performance than their less educated peers. Among the highly educated participants, those with WMH over-recruited areas engaged by young volunteers and showed activation in additional cortical and subcortical structures. However, those with low WMH differed little with respect to their younger counterparts. Our findings demonstrate that the functional mechanisms subtending the effects of education, as a proxy of CR, are modulated according to the WMH burden. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Etiologic evaluation of periventricular hyperintensity in MR images of first-ever cerebral thrombosis

    Energy Technology Data Exchange (ETDEWEB)

    Iwamoto, Toshihiko; Enomoto, Mutsurou; Ogawa, Kimikazu; Yanagawa, Kiyotaka; Takasaki, Masaru [Tokyo Medical Coll. (Japan)

    1995-02-01

    To clarify the etiology of periventricular hyperintensity (PVH) seen on magnetic resonance (MR) images (especially on T2-weighted images), PVH was investigated in relation to causative lesions, angiographic findings, and risk factors for cerebrovascular accidents. The subjects were 103 patients with first-ever cerebral thrombosis (thrombosis group). Age-matched 37 patients with hypertension or diabetes mellitus (risk group) and 78 other patients with neither stroke nor any risk factor served as controls. MR imaging and angiography were undertaken within 3 months after the onset of stroke. Causative lesions were confined to the cerebral cortex (CR type, n=25), centrum semiovale (CS type, n=10), internal capsule/corona radiata (IC/CR type, n=46), and brainstem/cerebellum (BS type, n=22). PVH was classified into none, rims/caps, patchy, and diffuse. Patchy and diffuse types were significantly more common in the thrombosis group and the risk group of hypertensive patients than the other control patients. Diffuse type PVH coexisted with stenosed major cerebral artery and CS type infarction. In contrast, patchy PVH was closely correlated with IC/CR infarction caused by lesions of the perforating artery. These findings suggest that hemodynamic changes caused by large vessel diseases may result in diffuse PVH, while patchy PVH was confluent with multiple lesions induced by small vessel diseases. (N.K.).

  9. Bilateral hippocampal hyperintensities: a new finding in MR imaging of heat stroke

    Energy Technology Data Exchange (ETDEWEB)

    Janaki Sudhakar, Praharaju; Al-Hashimi, Hakima [Salmaniya Medical Complex, Department of Radiology, Manama (Bahrain)

    2007-12-15

    We present a child aged 2 years 3 months who suffered heat stroke after being accidentally locked in a car during summer. She was unconscious with hyperthermia on admission and later showed biochemical evidence of liver, cardiac and muscle injury and associated electrolyte imbalance. Her level of consciousness gradually improved, but she showed evidence of cortical blindness, which had improved on follow-up. MR imaging on the 5th day revealed bilateral hippocampal hyperintensities along with hyperintensities in the cerebellum and in the cerebral cortex. Previous case reports of imaging in heat stroke revealed involvement of the cerebellum, thalami, basal ganglia and scattered cerebral involvement. We report this unique finding of hippocampal hyperintensities due to heat stroke. (orig.)

  10. Bilateral hippocampal hyperintensities: a new finding in MR imaging of heat stroke

    International Nuclear Information System (INIS)

    Janaki Sudhakar, Praharaju; Al-Hashimi, Hakima

    2007-01-01

    We present a child aged 2 years 3 months who suffered heat stroke after being accidentally locked in a car during summer. She was unconscious with hyperthermia on admission and later showed biochemical evidence of liver, cardiac and muscle injury and associated electrolyte imbalance. Her level of consciousness gradually improved, but she showed evidence of cortical blindness, which had improved on follow-up. MR imaging on the 5th day revealed bilateral hippocampal hyperintensities along with hyperintensities in the cerebellum and in the cerebral cortex. Previous case reports of imaging in heat stroke revealed involvement of the cerebellum, thalami, basal ganglia and scattered cerebral involvement. We report this unique finding of hippocampal hyperintensities due to heat stroke. (orig.)

  11. Clinical feasibility of simultaneous multi-slice imaging with blipped-CAIPI for diffusion-weighted imaging and diffusion-tensor imaging of the brain.

    Science.gov (United States)

    Yokota, Hajime; Sakai, Koji; Tazoe, Jun; Goto, Mariko; Imai, Hiroshi; Teramukai, Satoshi; Yamada, Kei

    2017-12-01

    Background Simultaneous multi-slice (SMS) imaging is starting to be used in clinical situation, although evidence of clinical feasibility is scanty. Purpose To prospectively assess the clinical feasibility of SMS diffusion-weighted imaging (DWI) and diffusion-tensor imaging (DTI) with blipped-controlled aliasing in parallel imaging for brain lesions. Material and Methods The institutional review board approved this study. This study included 156 hyperintense lesions on DWI from 32 patients. A slice acceleration factor of 2 was applied for SMS scans, which allowed shortening of the scan time by 41.3%. The signal-to-noise ratio (SNR) was calculated for brain tissue of a selected slice. The contrast-to-noise ratio (CNR), apparent diffusion coefficient (ADC), and fractional anisotropy (FA) were calculated in 36 hyperintense lesions with a diameter of three pixels or more. Visual assessment was performed for all 156 lesions. Tractography of the corticospinal tract of 29 patients was evaluated. The number of tracts and averaged tract length were used for quantitative analysis, and visual assessment was evaluated by grading. Results The SMS scan showed no bias and acceptable 95% limits of agreement compared to conventional scans in SNR, CNR, and ADC on Bland-Altman analyses. Only FA of the lesions was higher in the SMS scan by 9% ( P = 0.016), whereas FA of the surrounding tissues was similar. Quantitative analysis of tractography showed similar values. Visual assessment of DWI hyperintense lesions and tractography also resulted in comparable evaluation. Conclusion SMS imaging was clinically feasible for imaging quality and quantitative values compared with conventional DWI and DTI.

  12. Diffusion Tensor Imaging-Based Research on Human White Matter Anatomy

    Directory of Open Access Journals (Sweden)

    Ming-guo Qiu

    2012-01-01

    Full Text Available The aim of this study is to investigate the white matter by the diffusion tensor imaging and the Chinese visible human dataset and to provide the 3D anatomical data of the corticospinal tract for the neurosurgical planning by studying the probabilistic maps and the reproducibility of the corticospinal tract. Diffusion tensor images and high-resolution T1-weighted images of 15 healthy volunteers were acquired; the DTI data were processed using DtiStudio and FSL software. The FA and color FA maps were compared with the sectional images of the Chinese visible human dataset. The probability maps of the corticospinal tract were generated as a quantitative measure of reproducibility for each voxel of the stereotaxic space. The fibers displayed by the diffusion tensor imaging were well consistent with the sectional images of the Chinese visible human dataset and the existing anatomical knowledge. The three-dimensional architecture of the white matter fibers could be clearly visualized on the diffusion tensor tractography. The diffusion tensor tractography can establish the 3D probability maps of the corticospinal tract, in which the degree of intersubject reproducibility of the corticospinal tract is consistent with the previous architectonic report. DTI is a reliable method of studying the fiber connectivity in human brain, but it is difficult to identify the tiny fibers. The probability maps are useful for evaluating and identifying the corticospinal tract in the DTI, providing anatomical information for the preoperative planning and improving the accuracy of surgical risk assessments preoperatively.

  13. White matter microstructural damage in small vessel disease is associated with Montreal cognitive assessment but not with mini mental state examination performances: vascular mild cognitive impairment Tuscany study.

    Science.gov (United States)

    Pasi, Marco; Salvadori, Emilia; Poggesi, Anna; Ciolli, Laura; Del Bene, Alessandra; Marini, Sandro; Nannucci, Serena; Pescini, Francesca; Valenti, Raffaella; Ginestroni, Andrea; Toschi, Nicola; Diciotti, Stefano; Mascalchi, Mario; Inzitari, Domenico; Pantoni, Leonardo

    2015-01-01

    Montreal Cognitive Assessment (MoCA) has been proposed as a screening tool in vascular cognitive impairment. Diffusion tensor imaging is sensitive to white matter microstructural damage. We investigated if diffusion tensor imaging-derived indices are more strongly associated with performances on MoCA or on the widely used mini mental state examination in patients with mild cognitive impairment and small vessel disease. Mild cognitive impairment patients with moderate/severe degrees of white matter hyperintensities on MRI were enrolled. Lacunar infarcts, cortical atrophy, medial temporal lobe atrophy and median values of mean diffusivity and fractional anisotropy of the cerebral white matter were studied and correlated with cognitive tests performances. Seventy-six patients (mean age 75.1±6.8 years, mean years of education 8.0±4.3) were assessed. In univariate analyses, a significant association of both MoCA and mini mental state examination scores with age, education, cortical atrophy, and medial temporal lobe atrophy was found, whereas mean diffusivity and fractional anisotropy were associated with MoCA. In partial correlation analyses, adjusting for all demographic and neuroimaging variables, both mean diffusivity and fractional anisotropy were associated only with MoCA (mean diffusivity: r= -0.275, P=0.023; fractional anisotropy: r=0.246, P=0.043). In patients with mild cognitive impairment and small vessel disease, diffusion tensor imaging-measured white matter microstructural damage is more related to MoCA than mini mental state examination performances. MoCA is suited for the cognitive screening of patients with small vessel disease. © 2014 American Heart Association, Inc.

  14. Diffusive instability of a kaon condensate in neutron star matter

    International Nuclear Information System (INIS)

    Kubis, Sebastian

    2004-01-01

    The beta equilibrated dense matter with kaon condensate is analyzed with respect to extended stability conditions, including charge fluctuations. This kind of the diffusive instability appeared to be common property in the kaon condensation case. Results for three different nuclear models are presented

  15. Differential Effect of Left vs. Right White Matter Hyperintensity Burden on Functional Decline: The Northern Manhattan Study

    Directory of Open Access Journals (Sweden)

    Mandip S. Dhamoon

    2017-09-01

    Full Text Available Asymmetry of brain dysfunction may disrupt brain network efficiency. We hypothesized that greater left-right white matter hyperintensity volume (WMHV asymmetry was associated with functional trajectories.Methods: In the Northern Manhattan Study, participants underwent brain MRI with axial T1, T2, and fluid attenuated inversion recovery sequences, with baseline interview and examination. Volumetric WMHV distribution across 14 brain regions was determined separately by combining bimodal image intensity distribution and atlas based methods. Participants had annual functional assessments with the Barthel index (BI, range 0–100 over a mean of 7.3 years. Generalized estimating equations (GEE models estimated associations of regional WMHV and regional left-right asymmetry with baseline BI and change over time, adjusted for baseline medical risk factors, sociodemographics, and cognition, and stroke and myocardial infarction during follow-up.Results: Among 1,195 participants, greater WMHV asymmetry in the parietal lobes (−8.46 BI points per unit greater WMHV on the right compared to left, 95% CI −3.07, −13.86 and temporal lobes (−2.48 BI points, 95% CI −1.04, −3.93 was associated with lower overall function. Greater WMHV asymmetry in the parietal lobes (−1.09 additional BI points per year per unit greater WMHV on the left compared to right, 95% CI −1.89, −0.28 was independently associated with accelerated functional decline.Conclusions: In this large population-based study with long-term repeated measures of function, greater regional WMHV asymmetry was associated with lower function and functional decline. In addition to global WMHV, WHMV asymmetry may be an important predictor of long-term functional status.

  16. Muscle mass decline, arterial stiffness, white matter hyperintensity, and cognitive impairment: Japan Shimanami Health Promoting Program study.

    Science.gov (United States)

    Kohara, Katsuhiko; Okada, Yoko; Ochi, Masayuki; Ohara, Maya; Nagai, Tokihisa; Tabara, Yasuharu; Igase, Michiya

    2017-08-01

    There is a close association between frailty and cognitive impairment. However, the underlying contribution of sarcopenia to the development of cognitive impairment is unclear. We investigated the possible association between muscle mass decline and cognitive impairment in a cross-sectional study of 1518 subjects aged 55 years or above. We also evaluated arterial stiffness and white matter hyperintensities (WMHs) as possible underlying mechanisms for this association. Two sarcopenic indices were measured: thigh muscle cross-sectional area (CSA; calculated by computed tomography) and skeletal muscle mass (bioelectric impedance). Muscle mass decline was defined as either the bottom 10% or 20% of participants for each sex. Cognitive function was assessed using the Touch Panel-type Dementia Assessment Scale, and brachial-ankle pulse wave velocity was measured as an index of arterial stiffness. Both sarcopenic indices were modestly but significantly associated with brachial-ankle pulse wave velocity in male and female subjects. The presence of WMHs was significantly associated with low thigh muscle CSA in men and with low skeletal muscle mass in women. The Touch Panel-type Dementia Assessment Scale score was modestly but significantly and positively associated with thigh muscle CSA in men and skeletal muscle mass in women. Muscle mass decline in the bottom 10% of participants on both sarcopenic indices was significantly and independently related to cognitive impairment in women. Lower sarcopenic indices are significantly related to lower cognitive scores. Arterial stiffness and WMHs could account, at least in part, for this association. © 2017 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

  17. White matter injury in newborns with congenital heart disease: a diffusion tensor imaging study.

    Science.gov (United States)

    Mulkey, Sarah B; Ou, Xiawei; Ramakrishnaiah, Raghu H; Glasier, Charles M; Swearingen, Christopher J; Melguizo, Maria S; Yap, Vivien L; Schmitz, Michael L; Bhutta, Adnan T

    2014-09-01

    Brain injury is observed on cranial magnetic resonance imaging preoperatively in up to 50% of newborns with congenital heart disease. Newer imaging techniques such as diffusion tensor imaging provide sensitive measures of the white matter integrity. The objective of this study was to evaluate the diffusion tensor imaging analysis technique of tract-based spatial statistics in newborns with congenital heart disease. Term newborns with congenital heart disease who would require surgery at less than 1 month of age were prospectively enrolled (n = 19). Infants underwent preoperative and postoperative brain magnetic resonance imaging with diffusion tensor imaging. Tract-based spatial statistics, an objective whole-brain diffusion tensor imaging analysis technique, was used to determine differences in white matter fractional anisotropy between infant groups. Term control infants were also compared with congenital heart disease infants. Postmenstrual age was equivalent between congenital heart disease infant groups and between congenital heart disease and control infants. Ten infants had preoperative brain injury, either infarct or white matter injury, by conventional brain magnetic resonance imaging. The technique of tract-based spatial statistics showed significantly lower fractional anisotropy (P tensor imaging analysis technique that may have better sensitivity in detecting white matter injury compared with conventional brain magnetic resonance imaging in term newborns with congenital heart disease. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Hyperintense Acute Reperfusion Marker on FLAIR in a Patient with Transient Ischemic Attack

    Directory of Open Access Journals (Sweden)

    Alex Förster

    2016-01-01

    Full Text Available The hyperintense acute reperfusion marker (HARM has initially been described in acute ischemic stroke. The phenomenon is caused by blood-brain barrier disruption following acute reperfusion and consecutive delayed gadolinium enhancement in the subarachnoid space on fluid attenuated inversion recovery (FLAIR images. Here we report the case of an 80-year-old man who presented with transient paresis and sensory loss in the right arm. Initial routine stroke MRI including diffusion- and perfusion-weighted imaging demonstrated no acute pathology. Follow-up MRI after three hours demonstrated subarachnoid gadolinium enhancement in the left middle cerebral artery territory consistent with HARM that completely resolved on follow-up MRI three days later. This case illustrates that even in transient ischemic attack patients disturbances of the blood-brain barrier may be present which significantly exceed the extent of acute ischemic lesions on diffusion-weighted imaging. Inclusion of FLAIR images with delayed acquisition after intravenous contrast agent application in MRI stroke protocols might facilitate the diagnosis of a recent acute ischemic stroke.

  19. Frontal white matter hyperintensity predicts lower urinary tract dysfunction in older adults with amnestic mild cognitive impairment and Alzheimer's disease.

    Science.gov (United States)

    Ogama, Noriko; Yoshida, Masaki; Nakai, Toshiharu; Niida, Shumpei; Toba, Kenji; Sakurai, Takashi

    2016-02-01

    Lower urinary tract symptoms often limit activities of daily life and impair quality of life in the elderly. The purpose of the present study was to determine whether regional white matter hyperintensity (WMH) can predict lower urinary tract symptoms in elderly with amnestic mild cognitive impairment or Alzheimer's disease. The participants were 461 patients aged 65-85 years diagnosed with amnestic mild cognitive impairment or Alzheimer's disease. Patients and their caregivers were asked about symptoms of lower urinary tract symptoms (urinary difficulty, frequency and incontinence). Cognition, behavior and psychological symptoms of dementia and medication were evaluated. WMH and brain atrophy were analyzed using an automatic segmentation program. Regional WMH was evaluated in the frontal, parietal, temporal and occipital lobes. Patients with urinary incontinence showed significantly greater volume of WMH. WMH increased with age, especially in the frontal lobe. WMH in the frontal lobe was closely associated with urinary incontinence after adjustment for brain atrophy and classical confounding factors. Frontal WMH was a predictive factor for urinary incontinence in older adults with amnestic mild cognitive impairment or Alzheimer's disease. Urinary incontinence in demented older adults is not an incidental event, and careful insight into regional WMH on brain magnetic resonance imaging might greatly help in diagnosing individuals with a higher risk of urinary incontinence. © 2015 Japan Geriatrics Society.

  20. Relationship between white matter hyperintensities volume and the circle of Willis configurations in patients with carotid artery pathology.

    Science.gov (United States)

    Saba, Luca; Sanfilippo, Roberto; Porcu, Michele; Lucatelli, Pierleone; Montisci, Roberto; Zaccagna, Fulvio; Suri, Jasjit S; Anzidei, Michele; Wintermark, Max

    2017-04-01

    We aimed to assess if there is a difference of distribution and volume of white matter hyperintensities (WMH) in the brain according to the Circle of Willis (CoW) configuration in patients with carotid artery pathology. One-hundred consecutive patients (79 males, 21 females; mean age 70 years; age range 46-84 years) that underwent brain MRI before carotid endarterectomy (CEA) were included. FLAIR-WMH lesion volume was performed using a semi-automated segmentation technique and the status of the circle of Willis was assessed by two neuroradiologists in consensus. We found a prevalence of 55% of variants in the CoW configuration; 22 cases had one variants (40%); 25 cases had two variants (45.45%) and 8 cases showed 3 variants (14.55%). The configuration that was associated with the biggest WMH volume and number of lesions was the A1+PcoA+PcoA. The PcoA variants were the most prevalent and there was no statistically significant difference in number of lesions and WMH for each vascular territory assessed and the same results were found for AcoA and A1 variants. Results of our study suggest that the more common CoW variants are not associated with the presence of an increased WMH or number of lesions whereas uncommon configurations, in particular when 2 or more segment are missing increase the WMH volume and number of lesions. The WHM volume of the MCA territory seems to be more affected by the CoW configuration. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Relationship between white matter hyperintensities volume and the circle of Willis configurations in patients with carotid artery pathology

    International Nuclear Information System (INIS)

    Saba, Luca; Sanfilippo, Roberto; Porcu, Michele; Lucatelli, Pierleone; Montisci, Roberto; Zaccagna, Fulvio; Suri, Jasjit S.; Anzidei, Michele; Wintermark, Max

    2017-01-01

    Purpose: We aimed to assess if there is a difference of distribution and volume of white matter hyperintensities (WMH) in the brain according to the Circle of Willis (CoW) configuration in patients with carotid artery pathology. Material and methods: One-hundred consecutive patients (79 males, 21 females; mean age 70 years; age range 46–84 years) that underwent brain MRI before carotid endarterectomy (CEA) were included. FLAIR-WMH lesion volume was performed using a semi-automated segmentation technique and the status of the circle of Willis was assessed by two neuroradiologists in consensus. Results: We found a prevalence of 55% of variants in the CoW configuration; 22 cases had one variants (40%); 25 cases had two variants (45.45%) and 8 cases showed 3 variants (14.55%). The configuration that was associated with the biggest WMH volume and number of lesions was the A1 + PcoA + PcoA. The PcoA variants were the most prevalent and there was no statistically significant difference in number of lesions and WMH for each vascular territory assessed and the same results were found for AcoA and A1 variants. Conclusion: Results of our study suggest that the more common CoW variants are not associated with the presence of an increased WMH or number of lesions whereas uncommon configurations, in particular when 2 or more segment are missing increase the WMH volume and number of lesions. The WHM volume of the MCA territory seems to be more affected by the CoW configuration.

  2. Relationship between white matter hyperintensities volume and the circle of Willis configurations in patients with carotid artery pathology

    Energy Technology Data Exchange (ETDEWEB)

    Saba, Luca, E-mail: lucasaba@tiscali.it [Department of Radiology, Azienda Ospedaliero Universitaria (A.O.U.), di Cagliari – Polo di Monserrato, s.s. 554 Monserrato, Cagliari 09045 (Italy); Sanfilippo, Roberto [Department of Vascular Surgery, Azienda Ospedaliero Universitaria (A.O.U.), di Cagliari – Polo di Monserrato, s.s. 554 Monserrato, Cagliari 09045 (Italy); Porcu, Michele [Department of Radiology, Azienda Ospedaliero Universitaria (A.O.U.), di Cagliari – Polo di Monserrato, s.s. 554 Monserrato, Cagliari 09045 (Italy); Lucatelli, Pierleone [Department of Radiology, University la Sapienza, Rome (Italy); Montisci, Roberto [Department of Vascular Surgery, Azienda Ospedaliero Universitaria (A.O.U.), di Cagliari – Polo di Monserrato, s.s. 554 Monserrato, Cagliari 09045 (Italy); Zaccagna, Fulvio [Department of Radiology, University la Sapienza, Rome (Italy); Suri, Jasjit S. [Monitoring and Diagnostic Division, AtheroPoint, Roseville, CA (United States); Point-of-Care Devices, Global Biomedical Technologies, Inc., Roseville, CA (United States); Department of Electrical Engineering, University of Idaho (Affl.), ID (United States); Anzidei, Michele [Department of Radiology, University la Sapienza, Rome (Italy); Wintermark, Max [Department of Radiology, Stanford University (United States)

    2017-04-15

    Purpose: We aimed to assess if there is a difference of distribution and volume of white matter hyperintensities (WMH) in the brain according to the Circle of Willis (CoW) configuration in patients with carotid artery pathology. Material and methods: One-hundred consecutive patients (79 males, 21 females; mean age 70 years; age range 46–84 years) that underwent brain MRI before carotid endarterectomy (CEA) were included. FLAIR-WMH lesion volume was performed using a semi-automated segmentation technique and the status of the circle of Willis was assessed by two neuroradiologists in consensus. Results: We found a prevalence of 55% of variants in the CoW configuration; 22 cases had one variants (40%); 25 cases had two variants (45.45%) and 8 cases showed 3 variants (14.55%). The configuration that was associated with the biggest WMH volume and number of lesions was the A1 + PcoA + PcoA. The PcoA variants were the most prevalent and there was no statistically significant difference in number of lesions and WMH for each vascular territory assessed and the same results were found for AcoA and A1 variants. Conclusion: Results of our study suggest that the more common CoW variants are not associated with the presence of an increased WMH or number of lesions whereas uncommon configurations, in particular when 2 or more segment are missing increase the WMH volume and number of lesions. The WHM volume of the MCA territory seems to be more affected by the CoW configuration.

  3. FLAIR vascular hyperintensities predict early ischemic recurrence in TIA.

    Science.gov (United States)

    Nam, Ki-Woong; Kim, Chi Kyung; Kim, Tae Jung; Oh, Kyungmi; Han, Moon-Ku; Ko, Sang-Bae; Yoon, Byung-Woo

    2018-02-27

    To evaluate the relationship between fluid-attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH) and early ischemic lesion recurrence (follow-up diffusion-weighted imaging [FU-DWI] [+]) in patients with lesion-negative TIA. We recruited consecutive patients with lesion-negative TIA within 24 hours of symptom onset, who underwent follow-up MRI during the acute period. FVH was defined as a focal or serpentine high signal intensity on FLAIR images. Other potential confounders were adjusted to evaluate the relationship between FVH and FU-DWI (+). Furthermore, to compare clinical outcomes between the FU-DWI (+) and FU-DWI (-) groups, we assessed 1-year recurrent ischemic stroke or TIA. Among 392 patients with lesion-negative TIA, 82 patients had FU-DWI (+) on the follow-up MRI. In the multivariate analysis, FVH remained an independent predictor of FU-DWI (+) (adjusted odds ratio [aOR] = 4.77, 95% confidence interval [CI] 2.45-9.29, p TIA. As FU-DWI (+) frequently occurs during the acute period and has a subsequent worse outcome after discharge, additional radiologic or clinical markers for it are necessary. © 2018 American Academy of Neurology.

  4. Significance of periventricular hyperintensity in T2 weighted MRI on memory dysfunction and depression after stroke

    International Nuclear Information System (INIS)

    Bokura, Hirokazu; Kobayashi, Shotai; Yamaguchi, Shuhei; Yamashita, Kazuya; Koide, Hiromi

    1994-01-01

    We studied the effect of periventricular hyperintensity (PVH) in T2 weighted MRI on memory function and post-stroke depression in 159 patients with cerebrovacular disease. Memory function was assessed with Hasegawa's scale, and depressive state was estimated with Zung's self-rating depression scale. Patients showing diffusely distributed PVH had significantly low scores in memory function tests. Localized PVH around the anterior horns of the laterals ventricle was also associated with impaired memory function when the area of PVH was large. The incidence of post-stroke depression was high in patients with large PVH around the anterior horn in comparison with patients with PVH around the posterior horn. The severity of PVH around the posterior horn did not affect memory function and post-stroke depression. These findings suggest that memory dysfunction and post-stroke depression were accelerated by the diffusely or anteriorly distributed PVH. (author)

  5. White matter hyperintensities in Parkinson's disease: do they explain the disparity between the postural instability gait difficulty and tremor dominant subtypes?

    Directory of Open Access Journals (Sweden)

    Talia Herman

    Full Text Available BACKGROUND: Brain white matter hyperintensities (WMHs commonly observed on brain imaging of older adults are associated with balance and gait impairment and have also been linked to cognitive deficits. Parkinson's disease (PD is traditionally sub-classified into the postural instability gait difficulty (PIGD sub-type, and the tremor dominant (TD sub-type. Considering the known association between WMHs and axial symptoms like gait disturbances and postural instability, one can hypothesize that WMHs might contribute to the disparate clinical sub-types of patients with PD. METHODS: 110 patients with PD underwent a clinical evaluation and a 3T MRI exam. Based on the Unified Parkinson Disease Rating Scale, the patients were classified into motor sub-types, i.e., TD or PIGD, and scores reflecting PIGD and TD symptoms were computed. We compared white matter burden using three previously validated methods: one using a semi-quantitative visual rating scale in specific brain regions and two automated methods. RESULTS: Overall, MRI data were obtained in 104 patients. The mean WMHs scores and the percent of subjects with lesions in specific brain regions were similar in the two subtypes, p = 0.678. The PIGD and the TD scores did not differ even when comparing patients with a relatively high burden of WMHs to patients with a relatively low burden. Across most of the brain regions, mild to moderate correlations between WMHs and age were found (r = 0.23 to 0.41; p<0.021. Conversely, no significant correlations were found between WMHs and the PIGD score or disease duration. In addition, depressive symptoms and cerebro-vascular risk factors were similar among the two subtypes. CONCLUSIONS: In contrast to what has been reported previously among older adults, the present study could not demonstrate any association between WMHs and the PIGD or TD motor sub-types in patients with PD.

  6. Effect of antenatal growth and prematurity on brain white matter: diffusion tensor study

    International Nuclear Information System (INIS)

    Lepomaeki, V.; Paavilainen, T.; Komu, M.; Matomaeki, J.; Lapinleimu, H.; Liisa Lehtonen, L.; Hurme, S.; Haataja, L.; Parkkola, R.

    2012-01-01

    White matter maturation is characterised by increasing fractional anisotropy (FA) and decreasing mean diffusivity (MD). Contradictory results have been published on the effect of premature birth on white matter maturation at term-equivalent age. To assess the association of gestational age and low birth-weight-for-gestational-age (z-score) with white matter maturation. Infants (n = 76, 53 males) born at different gestational ages were imaged at term-equivalent age. Gestational age and birth weight z-score were used as continuous variables and the effect on diffusion parameters was assessed. Brain maturation was studied using regions-of-interest analysis in several white matter areas. Gestational age showed no significant effect on white matter maturation at term-equivalent age. Children with low birth weight z-score had lower FA in the genu and splenium of the corpus callosum (regression, P = 0.012 and P = 0.032; correlation, P = 0.009 and P = 0.006, respectively), and higher MD in the splenium of the corpus callosum (regression, P = 0.002; correlation, P = 0.0004) compared to children whose birth weight was appropriate for gestational age. Children with low birth weight relative to gestational age show delay and/or anomaly in white matter maturation at term-equivalent age. (orig.)

  7. Effect of antenatal growth and prematurity on brain white matter: diffusion tensor study

    Energy Technology Data Exchange (ETDEWEB)

    Lepomaeki, V. [Turku University Central Hospital, Medical Imaging Centre of Southwest Finland, Turku (Finland); Turku University Central Hospital, Turku PET-Centre, PO Box 52, Turku (Finland); Paavilainen, T.; Komu, M. [Turku University Central Hospital, Medical Imaging Centre of Southwest Finland, Turku (Finland); Matomaeki, J.; Lapinleimu, H.; Liisa Lehtonen, L. [Turku University Central Hospital and University of Turku, Department of Pediatrics, Turku (Finland); Hurme, S. [University of Turku, Department of Biostatistics, Turku (Finland); Haataja, L. [Turku University Central Hospital and University of Turku, Department of Pediatric Neurology, Turku (Finland); Parkkola, R. [Turku University Central Hospital, Medical Imaging Centre of Southwest Finland, Turku (Finland); Turku University Central Hospital, Turku PET-Centre, PO Box 52, Turku (Finland); University of Turku, Department of Diagnostic Radiology, Turku (Finland)

    2012-06-15

    White matter maturation is characterised by increasing fractional anisotropy (FA) and decreasing mean diffusivity (MD). Contradictory results have been published on the effect of premature birth on white matter maturation at term-equivalent age. To assess the association of gestational age and low birth-weight-for-gestational-age (z-score) with white matter maturation. Infants (n = 76, 53 males) born at different gestational ages were imaged at term-equivalent age. Gestational age and birth weight z-score were used as continuous variables and the effect on diffusion parameters was assessed. Brain maturation was studied using regions-of-interest analysis in several white matter areas. Gestational age showed no significant effect on white matter maturation at term-equivalent age. Children with low birth weight z-score had lower FA in the genu and splenium of the corpus callosum (regression, P = 0.012 and P = 0.032; correlation, P = 0.009 and P = 0.006, respectively), and higher MD in the splenium of the corpus callosum (regression, P = 0.002; correlation, P = 0.0004) compared to children whose birth weight was appropriate for gestational age. Children with low birth weight relative to gestational age show delay and/or anomaly in white matter maturation at term-equivalent age. (orig.)

  8. Conservative constraints on dark matter from the Fermi-LAT isotropic diffuse gamma-ray background spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Abazajian, Kevork N.; Agrawal, Prateek; Chacko, Zackaria [Maryland Center for Fundamental Physics, Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Kilic, Can, E-mail: kev@umd.edu, E-mail: apr@umd.edu, E-mail: zchacko@umd.edu, E-mail: kilic@physics.rutgers.edu [Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854 (United States)

    2010-11-01

    We examine the constraints on final state radiation from Weakly Interacting Massive Particle (WIMP) dark matter candidates annihilating into various standard model final states, as imposed by the measurement of the isotropic diffuse gamma-ray background by the Large Area Telescope aboard the Fermi Gamma-Ray Space Telescope. The expected isotropic diffuse signal from dark matter annihilation has contributions from the local Milky Way (MW) as well as from extragalactic dark matter. The signal from the MW is very insensitive to the adopted dark matter profile of the halos, and dominates the signal from extragalactic halos, which is sensitive to the low mass cut-off of the halo mass function. We adopt a conservative model for both the low halo mass survival cut-off and the substructure boost factor of the Galactic and extragalactic components, and only consider the primary final state radiation. This provides robust constraints which reach the thermal production cross-section for low mass WIMPs annihilating into hadronic modes. We also reanalyze limits from HESS observations of the Galactic Ridge region using a conservative model for the dark matter halo profile. When combined with the HESS constraint, the isotropic diffuse spectrum rules out all interpretations of the PAMELA positron excess based on dark matter annihilation into two lepton final states. Annihilation into four leptons through new intermediate states, although constrained by the data, is not excluded.

  9. Conservative constraints on dark matter from the Fermi-LAT isotropic diffuse gamma-ray background spectrum

    International Nuclear Information System (INIS)

    Abazajian, Kevork N.; Agrawal, Prateek; Chacko, Zackaria; Kilic, Can

    2010-01-01

    We examine the constraints on final state radiation from Weakly Interacting Massive Particle (WIMP) dark matter candidates annihilating into various standard model final states, as imposed by the measurement of the isotropic diffuse gamma-ray background by the Large Area Telescope aboard the Fermi Gamma-Ray Space Telescope. The expected isotropic diffuse signal from dark matter annihilation has contributions from the local Milky Way (MW) as well as from extragalactic dark matter. The signal from the MW is very insensitive to the adopted dark matter profile of the halos, and dominates the signal from extragalactic halos, which is sensitive to the low mass cut-off of the halo mass function. We adopt a conservative model for both the low halo mass survival cut-off and the substructure boost factor of the Galactic and extragalactic components, and only consider the primary final state radiation. This provides robust constraints which reach the thermal production cross-section for low mass WIMPs annihilating into hadronic modes. We also reanalyze limits from HESS observations of the Galactic Ridge region using a conservative model for the dark matter halo profile. When combined with the HESS constraint, the isotropic diffuse spectrum rules out all interpretations of the PAMELA positron excess based on dark matter annihilation into two lepton final states. Annihilation into four leptons through new intermediate states, although constrained by the data, is not excluded

  10. Diffusion tensor imaging, white matter lesions, the corpus callosum, and gait in the elderly

    Science.gov (United States)

    Gait impairment is common in the elderly, especially affected by stroke and white matter hyper intensities found in conventional brain magnetic resonance imaging (MRI). Diffusion tensor imaging (DTI) is more sensitive to white matter damage than conventional MRI. The relationship between DTI measure...

  11. HTLV-I carrier with unusual brain MR imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Yata, Shinsaku; Ogawa, Toshihide; Sugihara, Shuji; Matsusue, Eiji; Fujii, Shinya; Kinoshita, Toshibumi [Tottori University, Department of Pathophysiological and Therapeutic Science, Yonago (Japan); Faculty of Medicine, Tottori University, Yonago (Japan)

    2004-09-01

    We describe unusual brain MR imaging findings in a patient who is an HTLV-I carrier without myelopathy. T2-weighted MR images showed hyperintense signal abnormalities in the pyramidal tract, superior and middle cerebellar peduncles, and decussation of the superior cerebellar peduncles, in addition to subcortical white matter involvement. Diffusion-weighted images also showed hyperintense signal abnormalities in the same regions by T2 shine-through effect. (orig.)

  12. Hyperintense hepatocellular carcinoma on gadolinium-enhanced hepatic MRI

    International Nuclear Information System (INIS)

    Yoshikawa, Jun; Matsui, Osamu; Kadoya, Masumi; Gabata, Toshifumi; Arai, Kazunori; Takashima, Tsutomu

    1992-01-01

    We reported a phenomenon in which some hepatocellular carcinomas (HHCs) visualized as hypointense on plain T1 weighted MR images became hyperintense on gadolinium-DTPA (Gd-DTPA) (0.06∼0.23 mmol/kg) enhanced delayed images. Gd-DTPA enhanced images (using a super conducting magnet operating at 1.5T) of 44 HCCs were studied in comparison with contrast enhanced CT using 30∼80g of iodine. Six of 44 HCCs (14%) which were visualized as hypointense on plain T1 weighted image became hyperintense on delayed Gd-DTPA enhanced images. Although these were visualized as low intensity areas on both plain and enhanced CT, the contrast between HCC and the surrounding liver was small on post contrast CT. These findings were thought to be due to a stronger enhancement effect of Gd-DTPA than that of iodine. (author)

  13. Diffuse gamma ray constraints on annihilating or decaying Dark Matter after Fermi

    International Nuclear Information System (INIS)

    Cirelli, Marco; Panci, Paolo; Serpico, Pasquale D.

    2010-01-01

    We consider the diffuse gamma ray data from Fermi first year observations and compare them to the gamma ray fluxes predicted by Dark Matter annihilation or decay (both from prompt emission and from Inverse Compton Scattering), for different observation regions of the sky and a range of Dark Matter masses, annihilation/decay channels and Dark Matter galactic profiles. We find that the data exclude large regions of the Dark Matter parameter space not constrained otherwise and discuss possible directions for future improvements. Also, we further constrain Dark Matter interpretations of the e ± PAMELA/Fermi spectral anomalies, both for the annihilating and the decaying Dark Matter case: under very conservative assumptions, only models producing dominantly μ ± and assuming a cored Dark Matter galactic profile can fit the lepton data with masses around ∼2 TeV.

  14. MRI of paraventricular white matter lesions in amyotrophic lateral sclerosis. Analysis by diffusion-weighted images

    International Nuclear Information System (INIS)

    Segawa, Fuminori; Kinoshita, Masao; Kishibayashi, Jun; Kamada, Kazuhiko; Sunohara, Nobuhiko.

    1994-01-01

    Magnetic resonance images in some cases of amyotrophic lateral sclerosis (ALS) revealed abnormal signals in both the paraventriculer white matter and in the posterior limbs of the internal capsule. We examined T 2 - and diffusion-weighted MR images of these lesions in 18 cases of ALS. There were symmetrical high-signal areas in the posterior limbs of the internal capsule in all of the cases. The high-signal areas in the internal capsule corresponded to the pyramidal tracts in the anatomical atlas by Talairach. In 5 of the cases of ALS, T 2 -weighted MR images showed discrete paraventricular white matter lesions as well. The mean age of the ALS patients with paraventricular white matter lesions was higher than that of the ALS patients without such lesions. Proton densities calculated from the conventional MR images were higher in both the capsular and paraventricular lesions. The diffusion coefficients perpendicular to the pyramidal tract in the internal capsular lesions were within the normal range, where as the diffusion coefficients in the paraventricular lesions were increased in all directions. Thus, diffusion anisotropy was lost in the paraventricular lesions. These findings are similar to those observed in the white matter lesions of cerebro-vascular origin. As a result, the pathology of the paraventricular lesions in ALS was confirmed to be different from that of the internal capsular lesions. (author)

  15. MRI of paraventricular white matter lesions in amyotrophic lateral sclerosis. Analysis by diffusion-weighted images

    Energy Technology Data Exchange (ETDEWEB)

    Segawa, Fuminori; Kinoshita, Masao (Toho Univ., Tokyo (Japan). Ohashi Hospital); Kishibayashi, Jun; Kamada, Kazuhiko; Sunohara, Nobuhiko

    1994-09-01

    Magnetic resonance images in some cases of amyotrophic lateral sclerosis (ALS) revealed abnormal signals in both the paraventriculer white matter and in the posterior limbs of the internal capsule. We examined T[sub 2]- and diffusion-weighted MR images of these lesions in 18 cases of ALS. There were symmetrical high-signal areas in the posterior limbs of the internal capsule in all of the cases. The high-signal areas in the internal capsule corresponded to the pyramidal tracts in the anatomical atlas by Talairach. In 5 of the cases of ALS, T[sub 2]-weighted MR images showed discrete paraventricular white matter lesions as well. The mean age of the ALS patients with paraventricular white matter lesions was higher than that of the ALS patients without such lesions. Proton densities calculated from the conventional MR images were higher in both the capsular and paraventricular lesions. The diffusion coefficients perpendicular to the pyramidal tract in the internal capsular lesions were within the normal range, where as the diffusion coefficients in the paraventricular lesions were increased in all directions. Thus, diffusion anisotropy was lost in the paraventricular lesions. These findings are similar to those observed in the white matter lesions of cerebro-vascular origin. As a result, the pathology of the paraventricular lesions in ALS was confirmed to be different from that of the internal capsular lesions. (author).

  16. TM4SF20 Ancestral Deletion and Susceptibility to a Pediatric Disorder of Early Language Delay and Cerebral White Matter Hyperintensities

    Science.gov (United States)

    Wiszniewski, Wojciech; Hunter, Jill V.; Hanchard, Neil A.; Willer, Jason R.; Shaw, Chad; Tian, Qi; Illner, Anna; Wang, Xueqing; Cheung, Sau W.; Patel, Ankita; Campbell, Ian M.; Gelowani, Violet; Hixson, Patricia; Ester, Audrey R.; Azamian, Mahshid S.; Potocki, Lorraine; Zapata, Gladys; Hernandez, Patricia P.; Ramocki, Melissa B.; Santos-Cortez, Regie L.P.; Wang, Gao; York, Michele K.; Justice, Monica J.; Chu, Zili D.; Bader, Patricia I.; Omo-Griffith, Lisa; Madduri, Nirupama S.; Scharer, Gunter; Crawford, Heather P.; Yanatatsaneejit, Pattamawadee; Eifert, Anna; Kerr, Jeffery; Bacino, Carlos A.; Franklin, Adiaha I.A.; Goin-Kochel, Robin P.; Simpson, Gayle; Immken, Ladonna; Haque, Muhammad E.; Stosic, Marija; Williams, Misti D.; Morgan, Thomas M.; Pruthi, Sumit; Omary, Reed; Boyadjiev, Simeon A.; Win, Kay K.; Thida, Aye; Hurles, Matthew; Hibberd, Martin Lloyd; Khor, Chiea Chuen; Van Vinh Chau, Nguyen; Gallagher, Thomas E.; Mutirangura, Apiwat; Stankiewicz, Pawel; Beaudet, Arthur L.; Maletic-Savatic, Mirjana; Rosenfeld, Jill A.; Shaffer, Lisa G.; Davis, Erica E.; Belmont, John W.; Dunstan, Sarah; Simmons, Cameron P.; Bonnen, Penelope E.; Leal, Suzanne M.; Katsanis, Nicholas; Lupski, James R.; Lalani, Seema R.

    2013-01-01

    White matter hyperintensities (WMHs) of the brain are important markers of aging and small-vessel disease. WMHs are rare in healthy children and, when observed, often occur with comorbid neuroinflammatory or vasculitic processes. Here, we describe a complex 4 kb deletion in 2q36.3 that segregates with early childhood communication disorders and WMH in 15 unrelated families predominantly from Southeast Asia. The premature brain aging phenotype with punctate and multifocal WMHs was observed in ∼70% of young carrier parents who underwent brain MRI. The complex deletion removes the penultimate exon 3 of TM4SF20, a gene encoding a transmembrane protein of unknown function. Minigene analysis showed that the resultant net loss of an exon introduces a premature stop codon, which, in turn, leads to the generation of a stable protein that fails to target to the plasma membrane and accumulates in the cytoplasm. Finally, we report this deletion to be enriched in individuals of Vietnamese Kinh descent, with an allele frequency of about 1%, embedded in an ancestral haplotype. Our data point to a constellation of early language delay and WMH phenotypes, driven by a likely toxic mechanism of TM4SF20 truncation, and highlight the importance of understanding and managing population-specific low-frequency pathogenic alleles. PMID:23810381

  17. Effect of organic matter on 125I diffusion in bentonite

    International Nuclear Information System (INIS)

    Tao Wu; Qing Zheng

    2015-01-01

    Through-diffusion method was conducted to investigate the diffusion behavior of 125 I in bentonite in present of organic matter, such as polyaminopolycarboxylate EDTA, oxalic acid, hydrazine and humic acid HA. The effective diffusion coefficient D e value and rock capacity factor α were (2.32.6) × 10 -11 m 2 /s and 0.040-0.052, respectively. The small difference showed that iodine was preferentially associated with silicoaluminate mineral as an inorganic form. In present of HA, the D a value of 125 I was almost two orders of magnitude higher than that of HA and humic substances HS. The D e and α derived from the experiments were used to simulate its diffusion in the designed bentonite obstacle of high-level radioactive waste repository and the results showed that 125 I can be transported from 30 to 50 cm thickness of bentonite to the far-field of repository in several years. (author)

  18. Value of diffusion-weighted MR imaging in the diagnosis of Creutzfeldt-Jakob disease

    International Nuclear Information System (INIS)

    Xu Quangang; Wu Weiping; Huang Dehui; Zhang Jiatang; Lang Senyang; Pu Chuanqiang

    2005-01-01

    Objective: To assess the diagnosis value of diffusion- weighted imaging (DWI) in Creutzfeldt-Jakob disease (CJD). Methods: 8 cases of sporadic CJD who underwent MRI were reported. 4 cases were definite, 3 cases were probable and 1 case was possible. The sensitivity of DWI and conventional MRI were compared. Results: T 1 WI and T 2 WI revealed no abnormal signals except nonspecific diffuse brain atrophy in 4 cases, whereas DWI detected hyperintense abnormalities in all cases. 2 cases showed linear lesions only in the cerebral cortex, and 6 cases showed lesions in both the cerebral cortex and the striatum. The lesions were symmetric in 5 cases, but were asymmetric in the other 3 cases. Although fluid- attenuated inversion recovery (FLAIR) imaging also showed cortical hyperintensity in 1 case, the high signal changes were more evident and extensive on DWI. Conclusions: The hyperintense changes in the cerebral cortices and/or striata on DWI are considered characteristic of CJD. DWI is more sensitive than conventional MRI in depicting lesions of CJD and may be an essential tool for the early diagnosis of this disease. (authors)

  19. White Matter Hyperintensities on T2-Weighted MRI Images among DNA-Verified Older Familial Hypercholesterolemia Patients

    Energy Technology Data Exchange (ETDEWEB)

    Hyttinen, L. (Dept. of Internal Medicine, North Karelia Central Hospital, Joensuu (Finland)); Autti, T.; Soljanlahti, S. (Medical Imaging Center, Helsinki Univ. Central Hospital, Helsinki (Finland)); Rauma, S. (Dept. of Radiology, North Karelia Central Hospital, Joensuu (Finland)); Vuorio, A.F. (Dept. of Medicine, Univ. of Helsinki, Helsinki (Finland)); Strandberg, T.E. (Dept. of Health Sciences/Geriatrics, Univ. of Oulu, Oulu (Finland))

    2009-04-15

    Background: Familial hypercholesterolemia (FH) is a genetic disorder, causing an increased risk of coronary heart disease (CHD) if untreated. Silent brain infarctions and white matter hyperintensities (WMHIs) observed on T2-weighted magnetic resonance images (MRI) are associated with increased risk for stroke and myocardial infarction. Age is a strong predictor of WMHIs. Purpose: To use MRI to assess the presence of clinically silent brain lesions in older FH patients, and to compare the occurrence and size of these lesions in older FH patients with middle-aged FH patients and healthy controls. Material and Methods: A total of 43 older (age = 65 years) FH patients with the same FH North Karelia mutation, living in Finland, were identified. In this comprehensive cohort, 1.5T brain MRI was available for 33 individuals (age 65-84 years, M/F 9/24, mean duration of statin treatment 15.3 years). This group was divided into two age categories: 65-74 years (FHe1 group, n=23) and 75-84 years (FHe2 group, n=10). Infarcts, including lacunas, and WMHIs on T2-weighted images were recorded. Data from brain MRI were compared to those of a group of middle-aged FH patients with CHD (n=19, age 48-64 years) and with middle-aged healthy controls (n=29, age 49-63 years). Results: Only two (6%) of the older FH patients had clinically silent brain infarcts detected by MRI. The amount of large WMHIs (>5 mm in diameter) was similar in the FHe1 group compared with the groups of middle-aged FH patients and healthy controls, even though the FHe1 group was 13 years older. The total amount of WMHIs and the amount of large WMHIs were greatest in the FHe2 group. Conclusion: FH patients aged 65 to 74 years receiving long-term statin treatment (15 years) did not have more WMHIs on brain MRI compared to middle-aged FH patients and healthy controls.

  20. White Matter Hyperintensities on T2-Weighted MRI Images among DNA-Verified Older Familial Hypercholesterolemia Patients

    International Nuclear Information System (INIS)

    Hyttinen, L.; Autti, T.; Soljanlahti, S.; Rauma, S.; Vuorio, A.F.; Strandberg, T.E.

    2009-01-01

    Background: Familial hypercholesterolemia (FH) is a genetic disorder, causing an increased risk of coronary heart disease (CHD) if untreated. Silent brain infarctions and white matter hyperintensities (WMHIs) observed on T2-weighted magnetic resonance images (MRI) are associated with increased risk for stroke and myocardial infarction. Age is a strong predictor of WMHIs. Purpose: To use MRI to assess the presence of clinically silent brain lesions in older FH patients, and to compare the occurrence and size of these lesions in older FH patients with middle-aged FH patients and healthy controls. Material and Methods: A total of 43 older (age = 65 years) FH patients with the same FH North Karelia mutation, living in Finland, were identified. In this comprehensive cohort, 1.5T brain MRI was available for 33 individuals (age 65-84 years, M/F 9/24, mean duration of statin treatment 15.3 years). This group was divided into two age categories: 65-74 years (FHe1 group, n=23) and 75-84 years (FHe2 group, n=10). Infarcts, including lacunas, and WMHIs on T2-weighted images were recorded. Data from brain MRI were compared to those of a group of middle-aged FH patients with CHD (n=19, age 48-64 years) and with middle-aged healthy controls (n=29, age 49-63 years). Results: Only two (6%) of the older FH patients had clinically silent brain infarcts detected by MRI. The amount of large WMHIs (>5 mm in diameter) was similar in the FHe1 group compared with the groups of middle-aged FH patients and healthy controls, even though the FHe1 group was 13 years older. The total amount of WMHIs and the amount of large WMHIs were greatest in the FHe2 group. Conclusion: FH patients aged 65 to 74 years receiving long-term statin treatment (15 years) did not have more WMHIs on brain MRI compared to middle-aged FH patients and healthy controls

  1. Feasibility of ultrasound-guided high intensity focused ultrasound ablating uterine fibroids with hyperintense on T2-weighted MR imaging

    International Nuclear Information System (INIS)

    Zhao, Wen-Peng; Chen, Jin-Yun; Zhang, Lian; Li, Quan; Qin, Juan

    2013-01-01

    Purpose: To retrospectively investigate whether uterine fibroids with hyperintense on pretreatment T2-weighted magnetic resonance imaging (MRI) could be treated with ultrasound-guided high intensity focused ultrasound (USgHIFU). Materials and methods: 282 patients with 282 symptomatic uterine fibroids who underwent USgHIFU treatment were retrospectively analyzed. Based on the signal intensity of T2-weighted MRI, uterine fibroids were classified as hypointense, isointense and hyperintense. Hyperintense fibroids were subjectively further subdivided into heterogeneous hyperintense, slightly homogeneous hyperintense and markedly homogeneous hyperintense based on the signal intensity of fibroid relative to myometrium and endometrium on T2-weighted MRI. Enhanced MRI was performed within one month after HIFU treatment. Non-perfused volume (NPV, indicative of successful ablation) ratio, treatment time, treatment efficiency, energy effect ratio and adverse events were recorded. Results: The median volume of uterine fibroids was 70.3 cm 3 (interquartile range, 41.1–132.5 cm 3 ). The average NPV ratio, defined as non-perfused volume divided by the fibroid volume after HIFU treatment, was 76.8 ± 19.0% (range, 0–100%) in the 282 patients. It was 86.3 ± 11.9% (range, 40.9–100.0%) in the group with hypointense fibroids, 77.1 ± 16.5% (range, 32.2–100.0%) in isointense fibroids, and 67.6 ± 23.9% (range, 0–100.0%) in hyperintense fibroids. The lowest NPV ratio, lowest treatment efficiency, more treatment time, more sonication energy and pain scores were observed in the slightly homogeneous hyperintense fibroids, and the NPV ratio was 55.8 ± 26.7% (range, 0–83.9%) in this subgroup. Conclusion: Based on our results, the heterogeneous and markedly homogeneous hyperintense fibroids were suitable for USgHIFU, and only the slightly homogeneous hyperintense fibroids should be excluded

  2. MR imaging in solvent-induced chronic toxic encephalopathy

    International Nuclear Information System (INIS)

    Thuomas, K.AA.; Moeller, C.; Oedkvist, L.M.; Flodin, U.; Dige, N.

    1996-01-01

    To use MR to examine patients with CNS symptoms indicating chronic intoxication. Thirty-two subjects exposed to industrial solvents for 5 to 28 years and 40 age-matched, healthy controls were examined. All patients showed decreased signal in the basal ganglia on T2-weighted images. In 11 of the patients the white matter showed diffuse hyperintensity with loss of the grey-white matter discrimination and with distinct periventricular hyperintensities in 5 of the patients. The controls had no pathological changes in the brain. Although the relatively small number of patients may obscure the significance, findings observed on T2-weighted images were patchy periventricular hyperintensities and hypointensities in the basal ganglia. Fast spin-echo is a good technique with fast acquisition of images with true spin-echo contrast features. (orig.)

  3. White-matter tract abnormalities and antisocial behavior: A systematic review of diffusion tensor imaging studies across development

    Directory of Open Access Journals (Sweden)

    Rebecca Waller

    2017-01-01

    Full Text Available Antisocial behavior (AB, including aggression, violence, and theft, is thought be underpinned by abnormal functioning in networks of the brain critical to emotion processing, behavioral control, and reward-related learning. To better understand the abnormal functioning of these networks, research has begun to investigate the structural connections between brain regions implicated in AB using diffusion tensor imaging (DTI, which assesses white-matter tract microstructure. This systematic review integrates findings from 22 studies that examined the relationship between white-matter microstructure and AB across development. In contrast to a prior hypothesis that AB is associated with greater diffusivity specifically in the uncinate fasciculus, findings suggest that adult AB is associated with greater diffusivity across a range of white-matter tracts, including the uncinate fasciculus, inferior fronto-occipital fasciculus, cingulum, corticospinal tract, thalamic radiations, and corpus callosum. The pattern of findings among youth studies was inconclusive with both higher and lower diffusivity found across association, commissural, and projection and thalamic tracts.

  4. Microstructural changes in ischemic cortical gray matter predicted by a model of diffusion-weighted MRI.

    Science.gov (United States)

    Vestergaard-Poulsen, Peter; Hansen, Brian; Ostergaard, Leif; Jakobsen, Rikke

    2007-09-01

    To understand the diffusion attenuated MR signal from normal and ischemic brain tissue in order to extract structural and physiological information using mathematical modeling, taking into account the transverse relaxation rates in gray matter. We fit our diffusion model to the diffusion-weighted MR signal obtained from cortical gray matter in healthy subjects. Our model includes variable volume fractions, intracellular restriction effects, and exchange between compartments in addition to individual diffusion coefficients and transverse relaxation rates for each compartment. A global optimum was found from a wide range of parameter permutations using cluster computing. We also present simulations of cell swelling and changes of exchange rate and intracellular diffusion as possible cellular mechanisms in ischemia. Our model estimates an extracellular volume fraction of 0.19 in accordance with the accepted value from histology. The absolute apparent diffusion coefficient obtained from the model was similar to that of experiments. The model and the experimental results indicate significant differences in diffusion and transverse relaxation between the tissue compartments and slow water exchange. Our model reproduces the signal changes observed in ischemia via physiologically credible mechanisms. Our modeling suggests that transverse relaxation has a profound influence on the diffusion attenuated MR signal. Our simulations indicate cell swelling as the primary cause of the diffusion changes seen in the acute phase of brain ischemia. (c) 2007 Wiley-Liss, Inc.

  5. Homogeneity based segmentation and enhancement of Diffusion Tensor Images : a white matter processing framework

    OpenAIRE

    Rodrigues, P.R.

    2011-01-01

    In diffusion magnetic resonance imaging (DMRI) the Brownian motion of the water molecules, within biological tissue, is measured through a series of images. In diffusion tensor imaging (DTI) this diffusion is represented using tensors. DTI describes, in a non-invasive way, the local anisotropy pattern enabling the reconstruction of the nervous fibers - dubbed tractography. DMRI constitutes a powerful tool to analyse the structure of the white matter within a voxel, but also to investigate the...

  6. Multishot diffusion-weighted MR imaging features in acute trauma of spinal cord

    International Nuclear Information System (INIS)

    Zhang, Jin Song; Huan, Yi

    2014-01-01

    To analyse diffusion-weighted MRI of acute spinal cord trauma and evaluate its diagnostic value. Conventional MRI and multishot, navigator-corrected DWI were performed in 20 patients with acute spinal cord trauma using 1.5-T MR within 72 h after the onset of trauma. Twenty cases were classified into four categories according to the characteristics of DWI: (1) Oedema type: ten cases presented with variable hyperintense areas within the spinal cord. There were significant differences in the apparent diffusion coefficients (ADCs) between lesions and unaffected regions (t = -7.621, P < 0.01). ADC values of lesions were markedly lower than those of normal areas. (2) Mixed type: six cases showed heterogeneously hyperintense areas due to a mixture of haemorrhage and oedema. (3) Haemorrhage type: two cases showed lesions as marked hypointensity due to intramedullary haemorrhage. (4) Compressed type (by epidural haemorrhage): one of the two cases showed an area of mild hyperintensity in the markedly compressed cord due to epidural haematoma. Muti-shot DWI of the spinal cord can help visualise and evaluate the injured spinal cord in the early stage, especially in distinguishing the cytotoxic oedema from vasogenic oedema. It can assist in detecting intramedullary haemorrhage and may have a potential role in the evaluation of compressed spinal cord. (orig.)

  7. White matter microstructure in transsexuals and controls investigated by diffusion tensor imaging

    NARCIS (Netherlands)

    Kranz, Georg S; Hahn, Andreas; Kaufmann, Ulrike; Küblböck, Martin; Hummer, Allan; Ganger, Sebastian; Seiger, Rene; Winkler, Dietmar; Swaab, Dick F; Windischberger, Christian; Kasper, Siegfried; Lanzenberger, Rupert

    2014-01-01

    Biological causes underpinning the well known gender dimorphisms in human behavior, cognition, and emotion have received increased attention in recent years. The advent of diffusion-weighted magnetic resonance imaging has permitted the investigation of the white matter microstructure in

  8. Paradoxical embolisation and cerebral white matter lesions in dementia.

    NARCIS (Netherlands)

    Purandare, N.; Oude Voshaar, R.C.; McCollum, C.; Jackson, A.; Burns, A.

    2008-01-01

    The study aimed to examine the relationship between spontaneous cerebral emboli (SCE), patent foramen ovale (PFO) and white matter hyperintensities (WMH) on cerebral MRI in patients with Alzheimer's disease (AD) and vascular dementia (VaD). SCE were identified by transcranial Doppler of the middle

  9. The effects of white matter hyperintensities and amyloid deposition on Alzheimer dementia

    Directory of Open Access Journals (Sweden)

    Brian A. Gordon

    2015-01-01

    Conclusions: The amount of amyloid deposition and white matter damage independently predicts cognitive impairment. This suggests a diagnostic utility of qualitative white matter scales in addition to measuring amyloid levels.

  10. Cortical grey matter and subcortical white matter brain microstructural changes in schizophrenia are localised and age independent: a case-control diffusion tensor imaging study.

    Science.gov (United States)

    Chiapponi, Chiara; Piras, Fabrizio; Piras, Federica; Fagioli, Sabrina; Caltagirone, Carlo; Spalletta, Gianfranco

    2013-01-01

    It is still unknown whether the structural brain impairments that characterize schizophrenia (SZ) worsen during the lifetime. Here, we aimed to describe age-related microstructural brain changes in cortical grey matter and subcortical white matter of patients affected by SZ. In this diffusion tensor imaging study, we included 69 patients diagnosed with SZ and 69 healthy control (HC) subjects, age and gender matched. We carried out analyses of covariance, with diagnosis as fixed factor and brain diffusion-related parameters as dependent variables, and controlled for the effect of education. White matter fractional anisotropy decreased in the entire age range spanned (18-65 years) in both SZ and HC and was significantly lower in younger patients with SZ, with no interaction (age by diagnosis) effect in fiber tracts including corpus callosum, corona radiata, thalamic radiations and external capsule. Also, grey matter mean diffusivity increased in the entire age range in both SZ and HC and was significantly higher in younger patients, with no age by diagnosis interaction in the left frontal operculum cortex, left insula and left planum polare and in the right temporal pole and right intracalcarine cortex. In individuals with SZ we found that localized brain cortical and white matter subcortical microstructural impairments appear early in life but do not worsen in the 18-65 year age range.

  11. Cortical grey matter and subcortical white matter brain microstructural changes in schizophrenia are localised and age independent: a case-control diffusion tensor imaging study.

    Directory of Open Access Journals (Sweden)

    Chiara Chiapponi

    Full Text Available It is still unknown whether the structural brain impairments that characterize schizophrenia (SZ worsen during the lifetime. Here, we aimed to describe age-related microstructural brain changes in cortical grey matter and subcortical white matter of patients affected by SZ. In this diffusion tensor imaging study, we included 69 patients diagnosed with SZ and 69 healthy control (HC subjects, age and gender matched. We carried out analyses of covariance, with diagnosis as fixed factor and brain diffusion-related parameters as dependent variables, and controlled for the effect of education. White matter fractional anisotropy decreased in the entire age range spanned (18-65 years in both SZ and HC and was significantly lower in younger patients with SZ, with no interaction (age by diagnosis effect in fiber tracts including corpus callosum, corona radiata, thalamic radiations and external capsule. Also, grey matter mean diffusivity increased in the entire age range in both SZ and HC and was significantly higher in younger patients, with no age by diagnosis interaction in the left frontal operculum cortex, left insula and left planum polare and in the right temporal pole and right intracalcarine cortex. In individuals with SZ we found that localized brain cortical and white matter subcortical microstructural impairments appear early in life but do not worsen in the 18-65 year age range.

  12. Interacting diffusive unified dark energy and dark matter from scalar fields

    Energy Technology Data Exchange (ETDEWEB)

    Benisty, David; Guendelman, E.I. [Ben Gurion University of the Negev, Department of Physics, Beersheba (Israel)

    2017-06-15

    Here we generalize ideas of unified dark matter-dark energy in the context of two measure theories and of dynamical space time theories. In two measure theories one uses metric independent volume elements and this allows one to construct unified dark matter-dark energy, where the cosmological constant appears as an integration constant associated with the equation of motion of the measure fields. The dynamical space-time theories generalize the two measure theories by introducing a vector field whose equation of motion guarantees the conservation of a certain Energy Momentum tensor, which may be related, but in general is not the same as the gravitational Energy Momentum tensor. We propose two formulations of this idea: (I) by demanding that this vector field be the gradient of a scalar, (II) by considering the dynamical space field appearing in another part of the action. Then the dynamical space time theory becomes a theory of Diffusive Unified dark energy and dark matter. These generalizations produce non-conserved energy momentum tensors instead of conserved energy momentum tensors which leads at the end to a formulation of interacting DE-DM dust models in the form of a diffusive type interacting Unified dark energy and dark matter scenario. We solved analytically the theories for perturbative solution and asymptotic solution, and we show that the ΛCDM is a fixed point of these theories at large times. Also a preliminary argument as regards the good behavior of the theory at the quantum level is proposed for both theories. (orig.)

  13. AGREEMENT BETWEEN THE WHITE MATTER CONNECTIVITY BASED ON THE TENSOR-BASED MORPHOMETRY AND THE VOLUMETRIC WHITE MATTER PARCELLATIONS BASED ON DIFFUSION TENSOR IMAGING.

    Science.gov (United States)

    Kim, Seung-Goo; Lee, Hyekyoung; Chung, Moo K; Hanson, Jamie L; Avants, Brian B; Gee, James C; Davidson, Richard J; Pollak, Seth D

    2012-01-01

    We are interested in investigating white matter connectivity using a novel computational framework that does not use diffusion tensor imaging (DTI) but only uses T1-weighted magnetic resonance imaging. The proposed method relies on correlating Jacobian determinants across different voxels based on the tensor-based morphometry (TBM) framework. In this paper, we show agreement between the TBM-based white matter connectivity and the DTI-based white matter atlas. As an application, altered white matter connectivity in a clinical population is determined.

  14. Radiation-Induced Changes in Normal-Appearing White Matter in Patients With Cerebral Tumors: A Diffusion Tensor Imaging Study

    International Nuclear Information System (INIS)

    Nagesh, Vijaya; Tsien, Christina I.; Chenevert, Thomas L.; Ross, Brian D.; Lawrence, Theodore S.; Junick, Larry; Cao Yue

    2008-01-01

    Purpose: To quantify the radiation-induced changes in normal-appearing white matter before, during, and after radiotherapy (RT) in cerebral tumor patients. Methods and Materials: Twenty-five patients with low-grade glioma, high-grade glioma, or benign tumor treated with RT were studied using diffusion tensor magnetic resonance imaging. The biologically corrected doses ranged from 50 to 81 Gy. The temporal changes were assessed before, during, and to 45 weeks after the start of RT. The mean diffusivity of water ( ), fractional anisotropy of diffusion, diffusivity perpendicular (λ perpendicular ) and parallel (λ parallel ) to white matter fibers were calculated in normal-appearing genu and splenium of the corpus callosum. Results: In the genu and splenium, fractional anisotropy decreased and , λ parallel , λ -perpendicular increased linearly and significantly with time (p -perpendicular had increased ∼30% in the genu and splenium, and λ parallel had increased 5% in the genu and 9% in the splenium, suggesting that demyelination is predominant. The increases in λ perpendicular and λ parallel were dose dependent, starting at 3 weeks and continuing to 32 weeks from the start of RT. The dose-dependent increase in λ perpendicular and λ parallel was not sustained after 32 weeks, indicating the transition from focal to diffuse effects. Conclusion: The acute and subacute changes in normal-appearing white matter fibers indicate radiation-induced demyelination and mild structural degradation of axonal fibers. The structural changes after RT are progressive, with early dose-dependent demyelination and subsequent diffuse dose-independent demyelination and mild axonal degradation. Diffusion tensor magnetic resonance imaging is potentially a biomarker for the assessment of radiation-induced white matter injury

  15. L-2-hydroxyglutaric Aciduria in Two Female Yorkshire Terriers

    NARCIS (Netherlands)

    Sanchez-Masian, D.F.; Artuch, R.; Mascort, J.; Jakobs, C.A.J.M.; Salomons, G.S.; Zamora, A.; Casado, M.; Fernandez, M.; Recio, A.; Lujan, A.

    2012-01-01

    Two female Yorkshire terrier puppies were presented with generalized tonic-clonic seizures and ataxia. MRI revealed bilaterally symmetrical, diffuse regions of gray matter hyperintensity on T2-weighted and fluid-attenuated inversion recovery sequences. Urinary organic acids were quantified by gas

  16. AGREEMENT BETWEEN THE WHITE MATTER CONNECTIVITY BASED ON THE TENSOR-BASED MORPHOMETRY AND THE VOLUMETRIC WHITE MATTER PARCELLATIONS BASED ON DIFFUSION TENSOR IMAGING

    OpenAIRE

    Kim, Seung-Goo; Lee, Hyekyoung; Chung, Moo K.; Hanson, Jamie L.; Avants, Brian B.; Gee, James C.; Davidson, Richard J.; Pollak, Seth D.

    2012-01-01

    We are interested in investigating white matter connectivity using a novel computational framework that does not use diffusion tensor imaging (DTI) but only uses T1-weighted magnetic resonance imaging. The proposed method relies on correlating Jacobian determinants across different voxels based on the tensor-based morphometry (TBM) framework. In this paper, we show agreement between the TBM-based white matter connectivity and the DTI-based white matter atlas. As an application, altered white ...

  17. MR diffusion-weighted imaging in differential diagnosis of intracranial cystic lesions

    International Nuclear Information System (INIS)

    Ji Xueman; Lu Guangming; Wang Zhongqiu; Zhang Zongjun; Zhang Zhiqiang; Wang Junpeng

    2007-01-01

    Objective: To evaluate the value of diffusion-weighted imaging (DWI) on differential diagnosis of intracranial cystic lesions. Methods: Seventy-six patients with surgically and pathologically confirmed intracranial cystic lesions undergone conventional MRI, DWI and contrast enhanced MRI examination. The signal characteristics of intracranial cystic lesions on DWI were analysed retrospectively, the apparent diffusion coefficient (ADC) values of cystic areas were measured quantitatively. Results: Nineteen brain abscesses showed hyperintense signal on DWI. Among 34 brain tumors, 3 brain gliomas were hyperintense signal, 1 brain glioma was isointense signal and 1 metastasis was hyperintense signal; the other 29 brain tumors showed hypointense signal on DWI. The ADC values of all lesions were: (0.62 ± 0.15) x 10 -3 mm 2 /s in brain abscesses, (2.39 ± 0.78) x 10 -3 mm 2 /s in brain gliomas, (2.68 ± 0.40) x 10 -3 mm 2 /s in brain hemangioblastomas, (2.79 ± 0.79) x 10 -3 mm 2 /s in brain metastases, respectively. There were significant differences between the ADC values of brain abscess and the cystic or necrotic portions of brain glioma, hemangioblastoma, metastasis (P 0.05). Seven intracranial arachnoid cysts showed hypointense signal and 16 epidermoid cysts strikingly hyperintense signal on DWI. The ADC values of arachnoid cysts and epidermoid cysts were (2.96 ± 0.36) x 10 -3 mm 2 /s and (0.94 ± 0.13) x 10 -3 mm 2 /s respectively. There was significant difference between the ADC values of arachnoid cysts and epidermoid cysts (P<0.01). Conclusion: DWI and ADC values have important contribution to the differentiation of brain abscesses from cystic or necrotic tumors, intracranial cystic lesions showing hypointense signal on DWI can exclude brain abscess. (authors)

  18. Intraparenchymal epidermoid cysts in the brain: diagnostic value of MR diffusion-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hu, X.-Y. [Medical Imaging Center, The First Affiliated Hospital of Suzhou, Jiangsu Province (China); Hu, C.-H. [Imaging Center, Soochow University (China)], E-mail: wpdrhxy@hotmail.com; Fang, X.-M.; Cui, L.; Zhang, Q.-H. [Medical Imaging Center, The First Affiliated Hospital of Suzhou, Jiangsu Province (China)

    2008-07-15

    Aim: To evaluate the value of magnetic resonance (MR) diffusion-weighted imaging (DWI) and apparent diffusion coefficients (ADC) maps in the diagnosis of intraparenchymal epidermoid cysts (ECs). Materials and methods: Six cases of histopathologically proven intraparenchymal ECs were studied. All patients were examined with conventional MR (T1WI, T2WI, contrast-enhanced T1WI) and DWI sequences. Along with the mean ADC values (mADC) of the ECs, the cerebrospinal fluid (CSF) and grey matter (GM) were measured. Qualitative and quantitative assessments, as well as MRI findings, were retrospectively analysed using a double blind method by three radiologists in consensus. Results: Four lesions were located in the cerebellum, among them, one was accompanied by an arachnoid cyst; one huge lesion crossed the parenchyma of the frontal and temporal lobes; the other was located in the left temporal lobe. Two lesions had a homogeneous CSF-like intensity on both T1WI and T2WI. The other four were of mixed-intensity on both T1WI and T2WI. All lesions were strikingly hyperintense on DWI, and iso- or slightly hypointense on ADC (relative to the brain). The mADCs of the ECs were significantly higher than that of GM, but significantly lower than that of CSF. Three cases (3/6) were accurately diagnosed using conventional MR sequences without DWI, but in the remaining three cases, correct diagnosis could only be made with help of DWI. Conclusion: DWI sequences can facilitate the diagnosis of intraparenchymal ECs, thus alerting surgeons of the risk of chemical meningitis at surgery. The MR findings of intraparenchymal ECs are basically as the same as those of extracerebral ECs, but the former is likely to have a mixed signal. The hyperintense signal of ECs on DWI is probably caused by the T2 shine-through effect in tumour tissue.

  19. Evaluation of a deep learning approach for the segmentation of brain tissues and white matter hyperintensities of presumed vascular origin in MRI.

    Science.gov (United States)

    Moeskops, Pim; de Bresser, Jeroen; Kuijf, Hugo J; Mendrik, Adriënne M; Biessels, Geert Jan; Pluim, Josien P W; Išgum, Ivana

    2018-01-01

    Automatic segmentation of brain tissues and white matter hyperintensities of presumed vascular origin (WMH) in MRI of older patients is widely described in the literature. Although brain abnormalities and motion artefacts are common in this age group, most segmentation methods are not evaluated in a setting that includes these items. In the present study, our tissue segmentation method for brain MRI was extended and evaluated for additional WMH segmentation. Furthermore, our method was evaluated in two large cohorts with a realistic variation in brain abnormalities and motion artefacts. The method uses a multi-scale convolutional neural network with a T 1 -weighted image, a T 2 -weighted fluid attenuated inversion recovery (FLAIR) image and a T 1 -weighted inversion recovery (IR) image as input. The method automatically segments white matter (WM), cortical grey matter (cGM), basal ganglia and thalami (BGT), cerebellum (CB), brain stem (BS), lateral ventricular cerebrospinal fluid (lvCSF), peripheral cerebrospinal fluid (pCSF), and WMH. Our method was evaluated quantitatively with images publicly available from the MRBrainS13 challenge ( n  = 20), quantitatively and qualitatively in relatively healthy older subjects ( n  = 96), and qualitatively in patients from a memory clinic ( n  = 110). The method can accurately segment WMH (Overall Dice coefficient in the MRBrainS13 data of 0.67) without compromising performance for tissue segmentations (Overall Dice coefficients in the MRBrainS13 data of 0.87 for WM, 0.85 for cGM, 0.82 for BGT, 0.93 for CB, 0.92 for BS, 0.93 for lvCSF, 0.76 for pCSF). Furthermore, the automatic WMH volumes showed a high correlation with manual WMH volumes (Spearman's ρ  = 0.83 for relatively healthy older subjects). In both cohorts, our method produced reliable segmentations (as determined by a human observer) in most images (relatively healthy/memory clinic: tissues 88%/77% reliable, WMH 85%/84% reliable) despite various degrees of

  20. The study of the multiple sclerosis by using MR diffusion-weighted imaging

    International Nuclear Information System (INIS)

    Han Hongbin; Xie Jingxia; Liu Yi; Li Jian; Xie Ruping

    2002-01-01

    Objective: To summarize the appearances of MS lesions on DWI, and to quantitatively study the ADC and AI values in different clinical MS subgroups. Methods: One hundred and eighty-seven lesions were studied in 18 cases of MS at different clinical stage. Routine MR and DWI were performed in all cases. ADC and AI were calculated in the lesions, NAWM, and normal control group. Results: Hyperintensity (edema-like on T 2 WI) was demonstrated on DWI at acute primary progressive MS lesions. Hyperintense ring sign was found at acute relapse MS lesions. ADC increased in all subgroups of MS. Significant difference of ADC was demonstrated among MS lesions, NAWM, and normal control groups. Significant decrease of AI was demonstrated at later stages. Hyperintensity was found in all MS lesions on T 2 WI. The hyperintensity lesions on DWI had enhanced or non-enhanced appearance on CE-T 1 WI. The ADC value of enhanced MS lesions was less than that of the non-enhanced lesions (t = 4.19, P 0.05). Conclusion: DWI could give quantitative information for different pathological changes in MS lesions of different clinical subgroups. Quantitative measurement of diffusion has great potential value in the diagnosis, differential diagnosis, and the prediction of prognosis in MS

  1. Focal neuronal loss, reversible subcortical focal T2 hypointensity in seizures with a nonketotic hyperglycemic hyperosmolar state

    Energy Technology Data Exchange (ETDEWEB)

    Raghavendra, S.; Ashalatha, R.; Thomas, Sanjeev V. [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Department of Neurology, Trivandrum, Kerala (India); Kesavadas, C. [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Department of Imaging Sciences and Interventional Radiology, Trivandrum (India)

    2007-04-15

    Neuroimaging in seizures associated with nonketotic hyperglycemia (NKH) is considered normal. We report magnetic resonance imaging (MRI) abnormalities in four patients with NKH and seizures. We prospectively evaluated clinical and radiological abnormalities in four patients with NKH during the period March 2004 to December 2005. All patients presented with seizures, either simple or complex partial seizures or epilepsia partialis continua. Two of them had transient hemianopia. MRI showed subcortical T2 hypointensity in the occipital white matter and in or around the central sulcus (two patients each), T2 hyperintensity of the overlying cortex (two patients), focal overlying cortical enhancement (three patients) and bilateral striatal hyperintensity (one patient). Diffusion-weighted imaging (DWI) performed in three patients showed restricted diffusion. The ictal semiology and electroencephalographic (EEG) findings correlated with the MRI abnormalities. On clinical recovery, the subcortical T2 hypointensity and striatal hyperintensity reversed in all patients. The initial cortical change evolved to FLAIR hyperintensity suggestive of focal cortical gliosis. The radiological differential diagnosis considered initially included encephalitis, malignancy and hemorrhagic infarct rendering a diagnostic dilemma. We identified subcortical T2 hypointensity rather than hyperintensity as a characteristic feature of seizures associated with NKH. Only very few similar reports exist in literature. Reversible bilateral striatal T2 hyperintensity in NKH has not been reported to the best of our knowledge. (orig.)

  2. Focal neuronal loss, reversible subcortical focal T2 hypointensity in seizures with a nonketotic hyperglycemic hyperosmolar state

    International Nuclear Information System (INIS)

    Raghavendra, S.; Ashalatha, R.; Thomas, Sanjeev V.; Kesavadas, C.

    2007-01-01

    Neuroimaging in seizures associated with nonketotic hyperglycemia (NKH) is considered normal. We report magnetic resonance imaging (MRI) abnormalities in four patients with NKH and seizures. We prospectively evaluated clinical and radiological abnormalities in four patients with NKH during the period March 2004 to December 2005. All patients presented with seizures, either simple or complex partial seizures or epilepsia partialis continua. Two of them had transient hemianopia. MRI showed subcortical T2 hypointensity in the occipital white matter and in or around the central sulcus (two patients each), T2 hyperintensity of the overlying cortex (two patients), focal overlying cortical enhancement (three patients) and bilateral striatal hyperintensity (one patient). Diffusion-weighted imaging (DWI) performed in three patients showed restricted diffusion. The ictal semiology and electroencephalographic (EEG) findings correlated with the MRI abnormalities. On clinical recovery, the subcortical T2 hypointensity and striatal hyperintensity reversed in all patients. The initial cortical change evolved to FLAIR hyperintensity suggestive of focal cortical gliosis. The radiological differential diagnosis considered initially included encephalitis, malignancy and hemorrhagic infarct rendering a diagnostic dilemma. We identified subcortical T2 hypointensity rather than hyperintensity as a characteristic feature of seizures associated with NKH. Only very few similar reports exist in literature. Reversible bilateral striatal T2 hyperintensity in NKH has not been reported to the best of our knowledge. (orig.)

  3. Abnormal hyperintensity within the subarachnoid space evaluated by fluid-attenuated inversion-recovery MR imaging: a spectrum of central nervous system diseases

    International Nuclear Information System (INIS)

    Maeda, M.; Sakuma, H.; Takeda, K.; Yagishita, A.; Yamamoto, T.

    2003-01-01

    A variety of central nervous system (CNS) diseases are associated with abnormal hyperintensity within the subarachnoid space (SAS) by fluid-attenuated inversion-recovery (FLAIR) MR imaging. Careful attention to the SAS can provide additional useful information that may not be available with conventional MR sequences. The purpose of this article is to provide a pictorial essay about CNS diseases and FLAIR images with abnormal hyperintensity within the SAS. We present several CNS diseases including subarachnoid hemorrhage, meningitis, leptomeningeal metastases, acute infarction, and severe arterial occlusive diseases such as moya-moya disease. We also review miscellaneous diseases or normal conditions that may exhibit cerebrospinal fluid hyperintensity on FLAIR images. Although the detection of abnormal hyperintensity suggests the underlying CNS diseases and narrows differential diagnoses, FLAIR imaging sometimes presents artifactual hyperintensity within the SAS that can cause the misinterpretation of normal SAS as pathologic conditions; therefore, radiologists should be familiar with such artifactual conditions as well as pathologic conditions shown as hyperintensity by FLAIR images. This knowledge is helpful in establishing the correct diagnosis. (orig.)

  4. Brain MRI hyperintense lesions and cerebrovascular risk factors in the elderly

    International Nuclear Information System (INIS)

    Iidaka, Tetsuya

    1993-01-01

    It is known that asymptomatic MRI lesions of the brain are found in elderly subjects, but the significance of the lesions has not been determined. In previous reports, the prevalence of MRI lesions varied from 11% to 59%, but many of the authors indicated a close relationship with cerebrovascular risk factors. We evaluated 76 elderly subjects (over 60 years old, average age ±SD was 66.7±4.5) without a history of cerebrovascular disease and dementia, and determined the prevalence of periventricular (PVH), white matter (WMH) and pontine (PH) hyperintensity and risk factors. The severity of MRI lesion was evaluated in T2-weighted images by Fazekas' scoring method of MRI hyperintense lesions. PVH, WMH and PH were graded visually from 0 to 3 by the author and these points are added to the MRI score. In T1-weighted images, we also measured the diameter of the third ventricle, frontal horn and body of the lateral ventricle. Our results were that 62% of subjects had PVH, 64% had WMH and 8% had PH. In regard to risk factors, 38% of subjects had hypertension, 17% had diabetes mellitus, 8% had ischemic heart disease. The PVH (+) group was significantly older (p<0.01) and had larger lateral ventricles (p<0.05) than the PVH (-) group. The WMH (+) group was significantly older (p<0.05) and had higher risk of cerebrovascular disease (0.05) than the WMH (-) group. The MRI score was related, but not significantly, to a history of hypertension, diabetes mellitus and ischemic heart disease. The MRI score and index of ventricular enlargement correlated with age (p<0.05). In conclusion, PVH was related to aging and cerebrovascular risk factors. Therefore, PVH and WMH were suspected to have different pathogenesis and WMH was more closely related to risk factors. Our scoring method permits evaluation and comparison of MRI lesions of different groups. (author)

  5. The apparent diffusion coefficient of water in gray and white matter of the infant brain

    DEFF Research Database (Denmark)

    Toft, P B; Leth, H; Peitersen, Birgit

    1996-01-01

    PURPOSE: The purpose was to obtain normal values of the apparent diffusion coefficient (ADC) in the infant brain and to compare ADC maps with T1- and T2-weighted images. METHOD: Diffusion was measured in nine infants with an ECG-gated SE sequence compensated for first-order motion. One axial slice...... it appeared on T1- or T2-weighted images. In gray and white matter, the mean ADC ranged from 0.95 x 10(-9) to 1.76 x 10(-9) m2/s. In the frontal and occipital white matter, in the genu corporis callosi, and in the lentiform nucleus, the ADC decreased with increasing age. The cortex/white matter ratio...... of the ADC increased with age and approached 1 at the age of 30 weeks. CONCLUSION: ADC maps add information to the T1 and T2 images about the size and course of unmyelinated as well as myelinated tracts in the immature brain....

  6. The analysis of pathogenesis in the hypertensive encephalopathy using diffusion-weighted MR imaging

    International Nuclear Information System (INIS)

    Shim, Dong Jae; Lim, Myung Kwan; Kim, Hyung Jin; Cho, Young Kook; Suh, Chang Hae

    2001-01-01

    To investigate the nature of edematous lesions seen on MR images during acute episodes of hypertensive encephalopathy(HTE) with particular attention to the findings of diffusion-weighted imaging (DWI). A total of 17 MR examinations in fourteen patients with hypertensive encephalopathy were performed. The diagnoses were idiopathic HTE in eight cases, eclampsia in three, and cyclosporin-induced HTE in three. The apparent diffusion coefficients(ADCs) of edematous lesions and normal white matter revealed by DWI were assessed and compared, and the changes observed at follow-up MR imaging were analysed. DWI obtained within one week of the appearance of acute neurological symptoms revealed the edema as iso-intense in all patients with eclampsia and cyclosporin-induced HTE, and in five of eight patients with idiopathic HTE. In the other three patients with idiopathic HTE, DWI demonstrated slightly hyperintense edema. The ADCs of edematous lesion in patients with idiopathic HTE, eclampsia and cyclosporin-induced HTE were 1.21±0.34, 1.08±0.28, and 1.28±0.22 mm 2 /ms, respectively, while for normal white matter the corresponding figures were 0.77±0.25, 0.71±0.22, and 0.68±0.27mm 2 /ms The differences in ADCs between edema and normal white matter were thus significantly different between the three patient groups (p<0.05), while the ADCs of edematous lesions showed no significant variation between these groups (p<0.05). Follow-up MRI revealed that in three cases, edematous lesions were reversible and there were no residual signal changes. Vasogenic rather than cytotoxic edema is present during the acute stage of HTE

  7. Normal development of human brain white matter from infancy to early adulthood: a diffusion tensor imaging study.

    Science.gov (United States)

    Uda, Satoshi; Matsui, Mie; Tanaka, Chiaki; Uematsu, Akiko; Miura, Kayoko; Kawana, Izumi; Noguchi, Kyo

    2015-01-01

    Diffusion tensor imaging (DTI), which measures the magnitude of anisotropy of water diffusion in white matter, has recently been used to visualize and quantify parameters of neural tracts connecting brain regions. In order to investigate the developmental changes and sex and hemispheric differences of neural fibers in normal white matter, we used DTI to examine 52 healthy humans ranging in age from 2 months to 25 years. We extracted the following tracts of interest (TOIs) using the region of interest method: the corpus callosum (CC), cingulum hippocampus (CGH), inferior longitudinal fasciculus (ILF), and superior longitudinal fasciculus (SLF). We measured fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusivity (AD), and radial diffusivity (RD). Approximate values and changes in growth rates of all DTI parameters at each age were calculated and analyzed using LOESS (locally weighted scatterplot smoothing). We found that for all TOIs, FA increased with age, whereas ADC, AD and RD values decreased with age. The turning point of growth rates was at approximately 6 years. FA in the CC was greater than that in the SLF, ILF and CGH. Moreover, FA, ADC and AD of the splenium of the CC (sCC) were greater than in the genu of the CC (gCC), whereas the RD of the sCC was lower than the RD of the gCC. The FA of right-hemisphere TOIs was significantly greater than that of left-hemisphere TOIs. In infants, growth rates of both FA and RD were larger than those of AD. Our data show that developmental patterns differ by TOIs and myelination along with the development of white matter, which can be mainly expressed as an increase in FA together with a decrease in RD. These findings clarify the long-term normal developmental characteristics of white matter microstructure from infancy to early adulthood. © 2015 S. Karger AG, Basel.

  8. White matter correlates of cognitive domains in normal aging with diffusion tensor imaging

    Directory of Open Access Journals (Sweden)

    Efrat eSasson

    2013-03-01

    Full Text Available The ability to perform complex as well as simple cognitive tasks engages a network of brain regions that is mediated by the white matter fiber bundles connecting them. Different cognitive tasks employ distinctive white matter fiber bundles. The temporal lobe and its projections subserve a variety of key functions known to deteriorate during aging. In a cohort of 52 healthy subjects (ages 25-82 years, we performed voxel-wise regression analysis correlating performance in higher-order cognitive domains (executive function, information processing speed, and memory with white matter integrity, as measured by diffusion tensor imaging (DTI fiber tracking in the temporal lobe projections (uncinate fasciculus (UF, fornix, cingulum, inferior longitudinal fasciculus (ILF, and superior longitudinal fasciculus (SLF. The fiber tracts were spatially registered and statistical parametric maps were produced to spatially localize the significant correlations. Results showed that performance in the executive function domain is correlated with DTI parameters in the left SLF and right UF; performance in the information processing speed domain is correlated with fractional anisotropy (FA in the left cingulum, left fornix, right and left ILF and SLF; and the memory domain shows significant correlations with DTI parameters in the right fornix, right cingulum, left ILF, left SLF and right UF. These findings suggest that DTI tractography enables anatomical definition of region of interest for correlation of behavioral parameters with diffusion indices, and functionality can be correlated with white matter integrity.

  9. Thyroid-Stimulating Hormone, White Matter Hyperintensities, and Functional Outcome in Acute Ischemic Stroke Patients

    Directory of Open Access Journals (Sweden)

    Christopher O. Leonards

    2014-03-01

    Full Text Available Background: Thyroid-stimulating hormone (TSH concentrations are frequently altered in acute ischemic stroke patients. It is becoming increasingly apparent that various hormones in the hypothalamus-pituitary-thyroid axis may be associated with functional stroke outcome. We have previously shown that white matter hyperintensities (WMH of presumed vascular origin are strong indicators of functional outcome. It is unclear whether an association exists between WMH and TSH. We therefore sought to determine whether TSH levels, measured in acute ischemic stroke patients, are associated with WMH and functional outcome. Methods: We analyzed all first ischemic stroke patients who participated in the Berlin ‘Cream & Sugar' Study (NCT 01378468 and completed a 1-year follow-up assessment from January 2009 to March 2013. Patients were stratified into 3 groups: (1 low TSH (0.1-0.44 μU/ml; (2 normal TSH (0.44-2.5 μU/ml, and (3 high TSH (2.5-20 μU/ml. WMH were assessed using the Fazekas and Wahlund visual rating scales. Functional outcome was assessed using the modified Rankin Scale and was performed via telephone at 1 year by a certified rater. Results: 183 patients were included [median age 66, interquartile range (IQR 54-75; 33% females; median National Institute of Health Stroke Scale 3, IQR 1-4, range 0-24]. Venous samples were collected a median of 4 days (IQR 3-5 following initial symptom onset between 8 and 9 a.m. following a 10-hour fast. Patients with normal TSH levels (n = 132; 72% had significantly higher rates of prestroke diabetes than patients with high TSH levels (normal TSH 17%; high TSH 1%; p = 0.03. Additionally, patients with normal TSH levels tended to have higher estimated glomerular filtration rates than patients with high and low TSH concentrations (normal TSH median estimated glomerular filtration rates: 83 ml/min/1.73 m2; high TSH median estimated glomerular filtration rates: 76 ml/min/1.73 m2; low TSH median: 78 ml/min/1.73 m2; p

  10. Characteristics of lesional and extra-lesional cortical grey matter in relapsing-remitting and secondary progressive multiple sclerosis: A magnetisation transfer and diffusion tensor imaging study.

    Science.gov (United States)

    Yaldizli, Özgür; Pardini, Matteo; Sethi, Varun; Muhlert, Nils; Liu, Zheng; Tozer, Daniel J; Samson, Rebecca S; Wheeler-Kingshott, Claudia Am; Yousry, Tarek A; Miller, David H; Chard, Declan T

    2016-02-01

    In multiple sclerosis (MS), diffusion tensor and magnetisation transfer imaging are both abnormal in lesional and extra-lesional cortical grey matter, but differences between clinical subtypes and associations with clinical outcomes have only been partly assessed. To compare mean diffusivity, fractional anisotropy and magnetisation transfer ratio (MTR) in cortical grey matter lesions (detected using phase-sensitive inversion recovery (PSIR) imaging) and extra-lesional cortical grey matter, and assess associations with disability in relapse-onset MS. Seventy-two people with MS (46 relapsing-remitting (RR), 26 secondary progressive (SP)) and 36 healthy controls were included in this study. MTR, mean diffusivity and fractional anisotropy were measured in lesional and extra-lesional cortical grey matter. Mean fractional anisotropy was higher and MTR lower in lesional compared with extra-lesional cortical grey matter. In extra-lesional cortical grey matter mean fractional anisotropy and MTR were lower, and mean diffusivity was higher in the MS group compared with controls. Mean MTR was lower and mean diffusivity was higher in lesional and extra-lesional cortical grey matter in SPMS when compared with RRMS. These differences were independent of disease duration. In multivariate analyses, MTR in extra-lesional more so than lesional cortical grey matter was associated with disability. Magnetic resonance abnormalities in lesional and extra-lesional cortical grey matter are greater in SPMS than RRMS. Changes in extra-lesional compared with lesional cortical grey matter are more consistently associated with disability. © The Author(s), 2015.

  11. Episodic memory function is associated with multiple measures of white matter integrity in cognitive aging

    Directory of Open Access Journals (Sweden)

    Samuel Neal Lockhart

    2012-03-01

    Full Text Available Previous neuroimaging research indicates that white matter injury and integrity, measured respectively by white matter hyperintensities (WMH and fractional anisotropy (FA obtained from diffusion tensor imaging, differ with aging and cerebrovascular disease and are associated with episodic memory deficits in cognitively normal older adults. However, knowledge about tract-specific relationships between WMH, FA, and episodic memory in aging remains limited. We hypothesized that white matter connections between frontal cortex and subcortical structures as well as connections between frontal and temporo-parietal cortex would be most affected. In the current study, we examined relationships between WMH, FA and episodic memory in 15 young adults, 13 elders with minimal WMH and 15 elders with extensive WMH, using an episodic recognition memory test for object-color associations. Voxel-based statistics were used to identify voxel clusters where white matter measures were specifically associated with variations in episodic memory performance, and white matter tracts intersecting these clusters were analyzed to examine white matter-memory relationships. White matter injury and integrity measures were significantly associated with episodic memory in extensive regions of white matter, located predominantly in frontal, parietal, and subcortical regions. Template based tractography indicated that white matter injury, as measured by WMH, in the uncinate and inferior longitudinal fasciculi were significantly negatively associated with episodic memory performance. Other tracts such as thalamo-frontal projections, superior longitudinal fasciculus, and dorsal cingulum bundle demonstrated strong negative associations as well. The results suggest that white matter injury to multiple pathways, including connections of frontal and temporal cortex and frontal-subcortical white matter tracts, plays a critical role in memory differences seen in older individuals.

  12. Diffusion measures indicate fight exposure-related damage to cerebral white matter in boxers and mixed martial arts fighters.

    Science.gov (United States)

    Shin, W; Mahmoud, S Y; Sakaie, K; Banks, S J; Lowe, M J; Phillips, M; Modic, M T; Bernick, C

    2014-02-01

    Traumatic brain injury is common in fighting athletes such as boxers, given the frequency of blows to the head. Because DTI is sensitive to microstructural changes in white matter, this technique is often used to investigate white matter integrity in patients with traumatic brain injury. We hypothesized that previous fight exposure would predict DTI abnormalities in fighting athletes after controlling for individual variation. A total of 74 boxers and 81 mixed martial arts fighters were included in the analysis and scanned by use of DTI. Individual information and data on fight exposures, including number of fights and knockouts, were collected. A multiple hierarchical linear regression model was used in region-of-interest analysis to test the hypothesis that fight-related exposure could predict DTI values separately in boxers and mixed martial arts fighters. Age, weight, and years of education were controlled to ensure that these factors would not account for the hypothesized effects. We found that the number of knockouts among boxers predicted increased longitudinal diffusivity and transversal diffusivity in white matter and subcortical gray matter regions, including corpus callosum, isthmus cingulate, pericalcarine, precuneus, and amygdala, leading to increased mean diffusivity and decreased fractional anisotropy in the corresponding regions. The mixed martial arts fighters had increased transversal diffusivity in the posterior cingulate. The number of fights did not predict any DTI measures in either group. These findings suggest that the history of fight exposure in a fighter population can be used to predict microstructural brain damage.

  13. Thickening and enhancement of multiple cranial nerves in conjunction with cystic white matter lesions in early infantile Krabbe disease

    Energy Technology Data Exchange (ETDEWEB)

    Beslow, Lauren A.; Boennemann, Carsten G. [Children' s Hospital of Philadelphia, Division of Neurology, Philadelphia, PA (United States); Schwartz, Erin S. [Children' s Hospital of Philadelphia, Division of Neuroradiology, Philadelphia, PA (United States)

    2008-06-15

    We present serial MR findings in a child ultimately diagnosed with the early infantile form of Krabbe disease. MR showed typical features of Krabbe disease including cerebellar and brainstem hyperintensity, periventricular and deep white matter hyperintensity, and cerebral atrophy. In addition, the combination of both enlargement and enhancement of multiple cranial nerves in conjunction with unusual cystic lesions adjacent to the frontal horns of the lateral ventricles was previously unreported and expands the spectrum of imaging findings in early Krabbe disease. (orig.)

  14. Universal properties of relaxation and diffusion in condensed matter

    International Nuclear Information System (INIS)

    Ngai K L

    2017-01-01

    By and large the research communities today are not fully aware of the remarkable universality in the dynamic properties of many-body relaxation/diffusion processes manifested in experiments and simulations on condensed matter with diverse chemical compositions and physical structures. I shall demonstrate the universality first from the dynamic processes in glass-forming systems. This is reinforced by strikingly similar properties of different processes in contrasting interacting systems all having nothing to do with glass transition. The examples given here include glass-forming systems of diverse chemical compositions and physical structures, conductivity relaxation of ionic conductors (liquid, glassy, and crystalline), translation and orientation ordered phase of rigid molecule, and polymer chain dynamics. Universality is also found in the change of dynamics when dimension is reduced to nanometer size in widely different systems. The remarkable universality indicates that many-body relaxation/diffusion is governed by fundamental physics to be unveiled. One candidate is classical chaos on which the coupling model is based, Universal properties predicted by this model are in accord with diverse experiments and simulations. (paper)

  15. Comparing a diffusion tensor and non-tensor approach to white matter fiber tractography in chronic stroke.

    Science.gov (United States)

    Auriat, A M; Borich, M R; Snow, N J; Wadden, K P; Boyd, L A

    2015-01-01

    Diffusion tensor imaging (DTI)-based tractography has been used to demonstrate functionally relevant differences in white matter pathway status after stroke. However, it is now known that the tensor model is insensitive to the complex fiber architectures found in the vast majority of voxels in the human brain. The inability to resolve intra-voxel fiber orientations may have important implications for the utility of standard DTI-based tract reconstruction methods. Intra-voxel fiber orientations can now be identified using novel, tensor-free approaches. Constrained spherical deconvolution (CSD) is one approach to characterize intra-voxel diffusion behavior. In the current study, we performed DTI- and CSD-based tract reconstruction of the corticospinal tract (CST) and corpus callosum (CC) to test the hypothesis that characterization of complex fiber orientations may improve the robustness of fiber tract reconstruction and increase the sensitivity to identify functionally relevant white matter abnormalities in individuals with chronic stroke. Diffusion weighted magnetic resonance imaging was performed in 27 chronic post-stroke participants and 12 healthy controls. Transcallosal pathways and the CST bilaterally were reconstructed using DTI- and CSD-based tractography. Mean fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusivity (AD), and radial diffusivity (RD) were calculated across the tracts of interest. The total number and volume of reconstructed tracts was also determined. Diffusion measures were compared between groups (Stroke, Control) and methods (CSD, DTI). The relationship between post-stroke motor behavior and diffusion measures was evaluated. Overall, CSD methods identified more tracts than the DTI-based approach for both CC and CST pathways. Mean FA, ADC, and RD differed between DTI and CSD for CC-mediated tracts. In these tracts, we discovered a difference in FA for the CC between stroke and healthy control groups using CSD but

  16. Comparing a diffusion tensor and non-tensor approach to white matter fiber tractography in chronic stroke

    Directory of Open Access Journals (Sweden)

    A.M. Auriat

    2015-01-01

    Full Text Available Diffusion tensor imaging (DTI-based tractography has been used to demonstrate functionally relevant differences in white matter pathway status after stroke. However, it is now known that the tensor model is insensitive to the complex fiber architectures found in the vast majority of voxels in the human brain. The inability to resolve intra-voxel fiber orientations may have important implications for the utility of standard DTI-based tract reconstruction methods. Intra-voxel fiber orientations can now be identified using novel, tensor-free approaches. Constrained spherical deconvolution (CSD is one approach to characterize intra-voxel diffusion behavior. In the current study, we performed DTI- and CSD-based tract reconstruction of the corticospinal tract (CST and corpus callosum (CC to test the hypothesis that characterization of complex fiber orientations may improve the robustness of fiber tract reconstruction and increase the sensitivity to identify functionally relevant white matter abnormalities in individuals with chronic stroke. Diffusion weighted magnetic resonance imaging was performed in 27 chronic post-stroke participants and 12 healthy controls. Transcallosal pathways and the CST bilaterally were reconstructed using DTI- and CSD-based tractography. Mean fractional anisotropy (FA, apparent diffusion coefficient (ADC, axial diffusivity (AD, and radial diffusivity (RD were calculated across the tracts of interest. The total number and volume of reconstructed tracts was also determined. Diffusion measures were compared between groups (Stroke, Control and methods (CSD, DTI. The relationship between post-stroke motor behavior and diffusion measures was evaluated. Overall, CSD methods identified more tracts than the DTI-based approach for both CC and CST pathways. Mean FA, ADC, and RD differed between DTI and CSD for CC-mediated tracts. In these tracts, we discovered a difference in FA for the CC between stroke and healthy control groups

  17. Perilesional and contralateral white matter evolution and integrity in patients with periventricular nodular heterotopia and epilepsy: a longitudinal diffusion tensor imaging study.

    Science.gov (United States)

    Liu, W; Yan, B; An, D; Niu, R; Tang, Y; Tong, X; Gong, Q; Zhou, D

    2017-12-01

    This study aimed to assess the evolution of perinodular and contralateral white matter abnormalities in patients with periventricular nodular heterotopia (PNH) and epilepsy. Diffusion tensor imaging (DTI) (64 directions) and 3 T structural magnetic resonance imaging were performed in 29 PNH patients (mean age 27.3 years), and 16 patients underwent a second scan (average time between the two scans 1.1 years). Fractional anisotropy and mean diffusivity were measured within the perilesional and contralateral white matter. Longitudinal analysis showed that white matter located 10 mm from the focal nodule displayed characteristics intermediate to tissue 5 mm away, and normal-appearing white matter (NAWM) also established evolution profiles of perinodular white matter in different cortical lobes. Compared to 29 age- and sex-matched healthy controls, significant decreased fractional anisotropy and elevated mean diffusivity values were observed in regions 5 and 10 mm from nodules (P < 0.01), whilst DTI metrics of the remaining NAWM did not differ significantly from controls. Additionally, normal DTI metrics were shown in the contralateral region in patients with unilateral PNH. Periventricular nodular heterotopia is associated with microstructural abnormalities within the perilesional white matter and the extent decreases with increasing distance from the nodule. In the homologous contralateral region, white matter diffusion metrics were unchanged in unilateral PNH. These findings have clinical implications with respect to the medical and surgical interventions of PNH-related epilepsy. © 2017 EAN.

  18. Significance of T2 Hyperintensity on Magnetic Resonance Imaging After Cervical Cord Injury and Return to Play in Professional Athletes.

    Science.gov (United States)

    Tempel, Zachary J; Bost, Jeffrey W; Norwig, John A; Maroon, Joseph C

    2015-07-01

    Cervical cord magnetic resonance imaging (MRI) T2 hyperintensity is used as evidence of cord trauma in the evaluation and management of athletes in contact sports. The long-term pathophysiologic and prognostic value of this finding is poorly understood, especially in return to play (RTP). To examine the significance of T2 hyperintensity in the cervical spinal cord of professional athletes. Retrospective review of MRI T2 hyperintensity findings between 2007 and 2014 in 5 professional athletes. Pertinent examination and demographics, including mechanism of injury, surgical intervention, radiographs, MRI studies, long-term outcomes, and RTP recommendations were collected. Four National Football League players and 1 professional wrestler had prior traumatic neurapraxia that at the time of initial consultation had resolved. MRIs showed congenitally small cervical canal (1) and multilevel spondylosis/stenosis/disc herniation (4) along with focal cord T2 hyperintensity (5). The signal abnormalities were at C3/C4 (3), C4 mid-vertebral body (1), and C5/C6 (1). Four athletes had single-level anterior cervical discectomy and fusion, and 1 was nonoperative. Serial MRI imaging at 3 months after surgery showed hyperintensity partially resolved (4) and unchanged (1), and at 9-months 3 of the 5 completely resolved. Based on the author's RTP criteria, 4 of 5 were released to return to their sport. Clearance for RTP preceded complete resolution of MRI T2 hyperintensity in 3 of 4 athletes. The 2 athletes that have returned to profession sport have not had any additional episodes of neurapraxia or any cervical spine-related complications. MRI T2 hyperintensity in contact sport athletes who are symptom-free with normal examination and no evidence of spinal instability may not be a contraindication to RTP. Additional observations are needed to confirm this observation.

  19. Quantification of diffusion tensor imaging in normal white matter maturation of early childhood using an automated processing pipeline.

    Science.gov (United States)

    Loh, K B; Ramli, N; Tan, L K; Roziah, M; Rahmat, K; Ariffin, H

    2012-07-01

    The degree and status of white matter myelination can be sensitively monitored using diffusion tensor imaging (DTI). This study looks at the measurement of fractional anistropy (FA) and mean diffusivity (MD) using an automated ROI with an existing DTI atlas. Anatomical MRI and structural DTI were performed cross-sectionally on 26 normal children (newborn to 48 months old), using 1.5-T MRI. The automated processing pipeline was implemented to convert diffusion-weighted images into the NIfTI format. DTI-TK software was used to register the processed images to the ICBM DTI-81 atlas, while AFNI software was used for automated atlas-based volumes of interest (VOIs) and statistical value extraction. DTI exhibited consistent grey-white matter contrast. Triphasic temporal variation of the FA and MD values was noted, with FA increasing and MD decreasing rapidly early in the first 12 months. The second phase lasted 12-24 months during which the rate of FA and MD changes was reduced. After 24 months, the FA and MD values plateaued. DTI is a superior technique to conventional MR imaging in depicting WM maturation. The use of the automated processing pipeline provides a reliable environment for quantitative analysis of high-throughput DTI data. Diffusion tensor imaging outperforms conventional MRI in depicting white matter maturation. • DTI will become an important clinical tool for diagnosing paediatric neurological diseases. • DTI appears especially helpful for developmental abnormalities, tumours and white matter disease. • An automated processing pipeline assists quantitative analysis of high throughput DTI data.

  20. Microstructural changes in ischemic cortical gray matter predicted by a model of diffusion-weighted MRI

    DEFF Research Database (Denmark)

    Vestergaard-Poulsen, Peter; Hansen, Brian; Østergaard, Leif

    2007-01-01

    compartment. A global optimum was found from a wide range of parameter permutations using cluster computing. We also present simulations of cell swelling and changes of exchange rate and intracellular diffusion as possible cellular mechanisms in ischemia. RESULTS: Our model estimates an extracellular volume...... compartments and slow water exchange. Our model reproduces the signal changes observed in ischemia via physiologically credible mechanisms. CONCLUSION: Our modeling suggests that transverse relaxation has a profound influence on the diffusion attenuated MR signal. Our simulations indicate cell swelling...... model to the diffusion-weighted MR signal obtained from cortical gray matter in healthy subjects. Our model includes variable volume fractions, intracellular restriction effects, and exchange between compartments in addition to individual diffusion coefficients and transverse relaxation rates for each...

  1. Case Report: Compound heterozygous nonsense mutations in TRMT10A are associated with microcephaly, delayed development, and periventricular white matter hyperintensities [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Mohan Narayanan

    2015-09-01

    Full Text Available Microcephaly is a fairly common feature observed in children with delayed development, defined as head circumference less than 2 standard deviations below the mean for age and gender. It may be the result of an acquired insult to the brain, such prenatal or perinatal brain injury (congenital infection or hypoxic ischemic encephalopathy, or be a part of a genetic syndrome. There are over 1000 conditions listed in OMIM (Online Mendelian Inheritance in Man where microcephaly is a key finding; many of these are associated with specific somatic features and non-CNS anomalies. The term primary microcephaly is used when microcephaly and delayed development are the primary features, and they are not part of another recognized syndrome.   In this case report, we present the clinical features of siblings (brother and sister with primary microcephaly and delayed development, and subtle dysmorphic features. Both children had brain MRI studies that showed periventricular and subcortical T2/FLAIR hyperintensities, without signs of white matter volume loss, and no parenchymal calcifications by CT scan. The family was enrolled in a research study for whole exome sequencing of probands and parents. Analysis of variants determined that the children were compound heterozygotes for nonsense mutations, c.277C>T (p.Arg93* and c.397C>T (p.Arg133*, in the TRMT10A gene. Mutations in this gene have only recently been reported in children with microcephaly and early onset diabetes mellitus.   Our report adds to current knowledge of TRMT10A related neurodevelopmental disorders and demonstrates imaging findings suggestive of delayed or abnormal myelination of the white matter in this disorder. Accurate diagnosis through genomic testing, as in the children described here, allows for early detection and management of medical complications, such as diabetes mellitus.

  2. Galactic diffusion and the antiproton signal of supersymmetric dark matter

    CERN Document Server

    Chardonnet, P; Salati, Pierre; Taillet, R

    1996-01-01

    The leaky box model is now ruled out by measurements of a cosmic ray gradient throughout the galactic disk. It needs to be replaced by a more refined treatment which takes into account the diffusion of cosmic rays in the magnetic fields of the Galaxy. We have estimated the flux of antiprotons on the Earth in the framework of a two-zone diffusion model. Those species are created by the spallation reactions of high-energy nuclei with the interstellar gas. Another potential source of antiprotons is the annihilation of supersymmetric particles in the dark halo that surrounds our Galaxy. In this letter, we investigate both processes. Special emphasis is given to the antiproton signature of supersymmetric dark matter. The corresponding signal exceeds the conventional spallation flux below 300 MeV, a domain that will be thoroughly explored by the Antimatter Spectrometer experiment. The propagation of the antiprotons produced in the remote regions of the halo back to the Earth plays a crucial role. Depending on the e...

  3. Diffusion Tensor Imaging of Normal-Appearing White Matter as Biomarker for Radiation-Induced Late Delayed Cognitive Decline

    International Nuclear Information System (INIS)

    Chapman, Christopher H.; Nagesh, Vijaya; Sundgren, Pia C.; Buchtel, Henry; Chenevert, Thomas L.; Junck, Larry; Lawrence, Theodore S.; Tsien, Christina I.; Cao, Yue

    2012-01-01

    Purpose: To determine whether early assessment of cerebral white matter degradation can predict late delayed cognitive decline after radiotherapy (RT). Methods and Materials: Ten patients undergoing conformal fractionated brain RT participated in a prospective diffusion tensor magnetic resonance imaging study. Magnetic resonance imaging studies were acquired before RT, at 3 and 6 weeks during RT, and 10, 30, and 78 weeks after starting RT. The diffusivity variables in the parahippocampal cingulum bundle and temporal lobe white matter were computed. A quality-of-life survey and neurocognitive function tests were administered before and after RT at the magnetic resonance imaging follow-up visits. Results: In both structures, longitudinal diffusivity (λ ‖ ) decreased and perpendicular diffusivity (λ ⊥ ) increased after RT, with early changes correlating to later changes (p ⊥ at 3 weeks, and patients with >50% of cingula volume receiving >12 Gy had a greater increase in λ ⊥ at 3 and 6 weeks (p ‖ (30 weeks, p ‖ changes predicted for post-RT changes in verbal recall scores (3 and 6 weeks, p < .05). The neurocognitive test scores correlated significantly with the quality-of-life survey results. Conclusions: The correlation between early diffusivity changes in the parahippocampal cingulum and the late decline in verbal recall suggests that diffusion tensor imaging might be useful as a biomarker for predicting late delayed cognitive decline.

  4. Improving the realism of white matter numerical phantoms: a step towards a better understanding of the influence of structural disorders in diffusion MRI

    Science.gov (United States)

    Ginsburger, Kévin; Poupon, Fabrice; Beaujoin, Justine; Estournet, Delphine; Matuschke, Felix; Mangin, Jean-François; Axer, Markus; Poupon, Cyril

    2018-02-01

    White matter is composed of irregularly packed axons leading to a structural disorder in the extra-axonal space. Diffusion MRI experiments using oscillating gradient spin echo sequences have shown that the diffusivity transverse to axons in this extra-axonal space is dependent on the frequency of the employed sequence. In this study, we observe the same frequency-dependence using 3D simulations of the diffusion process in disordered media. We design a novel white matter numerical phantom generation algorithm which constructs biomimicking geometric configurations with few design parameters, and enables to control the level of disorder of the generated phantoms. The influence of various geometrical parameters present in white matter, such as global angular dispersion, tortuosity, presence of Ranvier nodes, beading, on the extra-cellular perpendicular diffusivity frequency dependence was investigated by simulating the diffusion process in numerical phantoms of increasing complexity and fitting the resulting simulated diffusion MR signal attenuation with an adequate analytical model designed for trapezoidal OGSE sequences. This work suggests that angular dispersion and especially beading have non-negligible effects on this extracellular diffusion metrics that may be measured using standard OGSE DW-MRI clinical protocols.

  5. Diffusion tensor imaging tensor shape analysis for assessment of regional white matter differences.

    Science.gov (United States)

    Middleton, Dana M; Li, Jonathan Y; Lee, Hui J; Chen, Steven; Dickson, Patricia I; Ellinwood, N Matthew; White, Leonard E; Provenzale, James M

    2017-08-01

    Purpose The purpose of this study was to investigate a novel tensor shape plot analysis technique of diffusion tensor imaging data as a means to assess microstructural differences in brain tissue. We hypothesized that this technique could distinguish white matter regions with different microstructural compositions. Methods Three normal canines were euthanized at seven weeks old. Their brains were imaged using identical diffusion tensor imaging protocols on a 7T small-animal magnetic resonance imaging system. We examined two white matter regions, the internal capsule and the centrum semiovale, each subdivided into an anterior and posterior region. We placed 100 regions of interest in each of the four brain regions. Eigenvalues for each region of interest triangulated onto tensor shape plots as the weighted average of three shape metrics at the plot's vertices: CS, CL, and CP. Results The distribution of data on the plots for the internal capsule differed markedly from the centrum semiovale data, thus confirming our hypothesis. Furthermore, data for the internal capsule were distributed in a relatively tight cluster, possibly reflecting the compact and parallel nature of its fibers, while data for the centrum semiovale were more widely distributed, consistent with the less compact and often crossing pattern of its fibers. This indicates that the tensor shape plot technique can depict data in similar regions as being alike. Conclusion Tensor shape plots successfully depicted differences in tissue microstructure and reflected the microstructure of individual brain regions. This proof of principle study suggests that if our findings are reproduced in larger samples, including abnormal white matter states, the technique may be useful in assessment of white matter diseases.

  6. Diffusion tensor MR imaging of white matter integrity in HIV-positive patients with planning deficit

    Energy Technology Data Exchange (ETDEWEB)

    Correa, Diogo Goulart; Doring, Thomas M.; Wilner, Nina Ventura; Cabral, Rafael Ferracini; Gasparetto, Emerson Leandro [Hospital Universitario Clementino Fraga Filho, Rio de Janeiro, RJ (Brazil); Clinica de Diagnostico por Imagem (CDPI), Rio de Janeiro, RJ (Brazil); Zimmermann, Nicolle; Fonseca, Rochele Paz [Hospital Universitario Clementino Fraga Filho, Rio de Janeiro, RJ (Brazil); Pontifical Catholic University of Rio Grande do Sul, Department of Psychology, Rio Grande do Sul (Brazil); Leite, Sarah C.B.; Bahia, Paulo R.V. [Hospital Universitario Clementino Fraga Filho, Rio de Janeiro, RJ (Brazil)

    2015-05-01

    The aim of this study was to evaluate whether normal controls and human immunodeficiency virus (HIV) patients with and without planning deficits differ on white matter integrity. A total of 34 HIV-positive patients with planning deficits were compared with 13 HIV-positive patients without planning deficits and 19 gender-, age-, and education-matched control subjects. Diffusion tensor imaging (DTI) was performed along 30 noncolinear directions in a 1.5-T scanner. For tract-based spatial statistics analysis, a white matter skeleton was created, and a permutation-based inference with 5000 permutations with a threshold of p < 0.05 was used to identify abnormalities in fractional anisotropy (FA). The median, radial, and axial diffusivities were also projected onto the mean FA skeleton. Compared with controls, HIV-positive patients with planning deficits had decreased FA in bilateral anterior thalamic radiations, bilateral inferior fronto-occiptal fasciculi, genu and splenium of the corpus callosum, bilateral superior longitudinal fascicule, and bilateral uncinate fasciculi. Compared to HIV-positive patients without planning deficits, patients with planning deficits had decreased FA in bilateral anterior thalamic radiations, bilateral inferior fronto-occiptal fasciculi, genu of the corpus callosum, bilateral superior longitudinal fascicule, and right uncinate fascicule. DTI can detect extensive white matter abnormalities in the normal-appearing white matter of HIV-positive patients with planning deficits compared with controls and HIV-positive patients without planning deficits. (orig.)

  7. Diffusion tensor MR imaging of white matter integrity in HIV-positive patients with planning deficit

    International Nuclear Information System (INIS)

    Correa, Diogo Goulart; Doring, Thomas M.; Wilner, Nina Ventura; Cabral, Rafael Ferracini; Gasparetto, Emerson Leandro; Zimmermann, Nicolle; Fonseca, Rochele Paz; Leite, Sarah C.B.; Bahia, Paulo R.V.

    2015-01-01

    The aim of this study was to evaluate whether normal controls and human immunodeficiency virus (HIV) patients with and without planning deficits differ on white matter integrity. A total of 34 HIV-positive patients with planning deficits were compared with 13 HIV-positive patients without planning deficits and 19 gender-, age-, and education-matched control subjects. Diffusion tensor imaging (DTI) was performed along 30 noncolinear directions in a 1.5-T scanner. For tract-based spatial statistics analysis, a white matter skeleton was created, and a permutation-based inference with 5000 permutations with a threshold of p < 0.05 was used to identify abnormalities in fractional anisotropy (FA). The median, radial, and axial diffusivities were also projected onto the mean FA skeleton. Compared with controls, HIV-positive patients with planning deficits had decreased FA in bilateral anterior thalamic radiations, bilateral inferior fronto-occiptal fasciculi, genu and splenium of the corpus callosum, bilateral superior longitudinal fascicule, and bilateral uncinate fasciculi. Compared to HIV-positive patients without planning deficits, patients with planning deficits had decreased FA in bilateral anterior thalamic radiations, bilateral inferior fronto-occiptal fasciculi, genu of the corpus callosum, bilateral superior longitudinal fascicule, and right uncinate fascicule. DTI can detect extensive white matter abnormalities in the normal-appearing white matter of HIV-positive patients with planning deficits compared with controls and HIV-positive patients without planning deficits. (orig.)

  8. Analyses of disruption of cerebral white matter integrity in schizophrenia with MR diffusion tensor fiber tracking method

    International Nuclear Information System (INIS)

    Yamamoto, Utako; Kobayashi, Tetsuo; Kito, Shinsuke; Koga, Yoshihiko

    2010-01-01

    We have analyzed cerebral white matter using magnetic resonance diffusion tensor imaging (MR-DTI) to measure the diffusion anisotropy of water molecules. The goal of this study is the quantitative evaluation of schizophrenia. Diffusion tensor images are acquired for patients with schizophrenia and healthy comparison subjects, group-matched for age, sex, and handedness. Fiber tracking is performed on the superior longitudinal fasciculus for the comparison between the patient and comparison groups. We have analysed and compared the cross-sectional area on the starting coronal plane and the mean and standard deviation of the fractional anisotropy and the apparent diffusion coefficient along fibers in the right and left hemispheres. In the right hemisphere, the cross-sectional areas in patient group are significantly smaller than those in the comparison group. Furthermore, in the comparison group, the cross-sectional areas in the right hemisphere are significantly larger than those in the left hemisphere, whereas there is no significant difference in the patient group. These results suggest that we may evaluate the disruption in white matter integrity in schizophrenic patients quantitatively by comparing the cross-sectional area of the superior longitudinal fasciculus in the right and left hemispheres. (author)

  9. Regional cerebral blood flow and periventricular hyperintensity in silent cerebral infarction. Comparison with multi-infarct dementia

    International Nuclear Information System (INIS)

    Koshi, Yasuhiko; Kitamura, Shin; Nagazumi, Atushi; Tsuganesawa, Toshikazu; Terashi, Akiro

    1996-01-01

    In order to investigate relationship between regional cerebral blood flow (rCBF) and the white matter lesions on MRI in silent cerebral infarction, we quantitatively measured rCBF by 123 I-IMP autoradiography method (IMP ARG method) and single photon emission tomography (SPECT) in 36 patients with silent cerebral infarction (SCI group), 22 patients with multi-infarct dementia (MID group), and 16 control subjects without periventricular hyperintensity (PVH) and lacunar infarction on MRI (CL group). Regions of interest (ROIs) on rCBF images were set in the frontal (F), temporal (T), parietal (P), occipital (O) cortex, and the cerebral white matter (W). The severity of PVH on MRI T 2 -weighted image was divided into four grades (grade 0-3). Though the frequency of hypertension was significantly higher in SCI group and MID group compared with CL group, no significant difference was seen in the mean age among these three groups. rCBF in the white matter and cerebral cortices except the occipital cortex in SCI group was significantly low compared with CL group (rCBF SCI /rCBF CL : W 0.87, F 0.87, T 0.87, P 0.88, O 0.92). rCBF in the white matter and cerebral cortices, especially in the white matter and frontal cortex, in MID group was significantly low compared with SCI group (rCBF MID /rCBF CL : W 0.69, F 0.71, T 0.74, P 0.75, O 0.81). The mean grade of PVH in MID group was significantly higher than that in SCI group (SCI 1.1 vs MID 2.5). The severity of PVH was significantly correlated with each rCBF in the white matter and cerebral cortices, especially in the white matter and frontal cortex. Our findings suggest that the quantitative measurement of rCBF by IMP ARG method is useful for the follow-up study in the patients with silent cerebral infarction as well as the evaluation of the severity of PVH on MRI. (author)

  10. Surface-based reconstruction and diffusion MRI in the assessment of gray and white matter damage in multiple sclerosis

    Science.gov (United States)

    Caffini, Matteo; Bergsland, Niels; LaganÃ, Marcella; Tavazzi, Eleonora; Tortorella, Paola; Rovaris, Marco; Baselli, Giuseppe

    2014-03-01

    Despite advances in the application of nonconventional MRI techniques in furthering the understanding of multiple sclerosis pathogenic mechanisms, there are still many unanswered questions, such as the relationship between gray and white matter damage. We applied a combination of advanced surface-based reconstruction and diffusion tensor imaging techniques to address this issue. We found significant relationships between white matter tract integrity indices and corresponding cortical structures. Our results suggest a direct link between damage in white and gray matter and contribute to the notion of gray matter loss relating to clinical disability.

  11. Spinal cord diffusion tensor imaging in patients with sensory neuronopathy

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes Casseb, Raphael [University of Campinas - UNICAMP, Department of Neurology, School of Medicine, Campinas, SP (Brazil); University of Campinas - UNICAMP, Neurophysics Group, Department of Cosmic Rays and Chronology, Institute of Physics Gleb Wataghin, Campinas, SP (Brazil); Ribeiro de Paiva, Jean Levi; Teixeira Branco, Lucas Melo; Muro Martinez, Alberto Rolim; Cavalcante Franca, Marcondes Jr. [University of Campinas - UNICAMP, Department of Neurology, School of Medicine, Campinas, SP (Brazil); Reis, Fabiano [University of Campinas - UNICAMP, Department of Radiology, School of Medicine, Campinas, SP (Brazil); Lima-Junior, Jose Carlos de [University of Campinas - UNICAMP, Laboratory of Cell Signaling, Department of Internal Medicine, Campinas, SP (Brazil); Castellano, Gabriela [University of Campinas - UNICAMP, Neurophysics Group, Department of Cosmic Rays and Chronology, Institute of Physics Gleb Wataghin, Campinas, SP (Brazil)

    2016-11-15

    We investigated whether MR diffusion tensor imaging (DTI) analysis of the cervical spinal cord could aid the (differential) diagnosis of sensory neuronopathies, an underdiagnosed group of diseases of the peripheral nervous system. We obtained spinal cord DTI and T2WI at 3 T from 28 patients, 14 diabetic subjects with sensory-motor distal polyneuropathy, and 20 healthy controls. We quantified DTI-based parameters and looked at the hyperintense T2W signal at the spinal cord posterior columns. Fractional anisotropy and mean diffusivity values at C2-C3 and C3-C4 levels were compared between groups. We also compared average fractional anisotropy (mean of values at C2-C3 and C3-C4 levels). A receiver operating characteristic (ROC) curve was used to determine diagnostic accuracy of average fractional anisotropy, and we compared its sensitivity against the hyperintense signal in segregating patients from the other subjects. Mean age and disease duration were 52 ± 10 and 11.4 ± 9.3 years in the patient group. Eighteen subjects had idiopathic disease and 6 dysimmune etiology. Fractional anisotropy at C3-C4 level and average fractional anisotropy were significantly different between patients and healthy controls (p < 0.001 and <0.001) and between patients and diabetic subjects (p = 0.019 and 0.027). Average fractional anisotropy presented an area under the curve of 0.838. Moreover, it had higher sensitivity than visual detection of the hyperintense signal (0.86 vs. 0.54), particularly for patients with short disease duration. DTI-based analysis enables in vivo detection of posterior column damage in sensory neuronopathy patients and is a useful diagnostic test for this condition. It also helps the differential diagnosis between sensory neuronopathy and distal polyneuropathies. (orig.)

  12. Spinal cord diffusion tensor imaging in patients with sensory neuronopathy

    International Nuclear Information System (INIS)

    Fernandes Casseb, Raphael; Ribeiro de Paiva, Jean Levi; Teixeira Branco, Lucas Melo; Muro Martinez, Alberto Rolim; Cavalcante Franca, Marcondes Jr.; Reis, Fabiano; Lima-Junior, Jose Carlos de; Castellano, Gabriela

    2016-01-01

    We investigated whether MR diffusion tensor imaging (DTI) analysis of the cervical spinal cord could aid the (differential) diagnosis of sensory neuronopathies, an underdiagnosed group of diseases of the peripheral nervous system. We obtained spinal cord DTI and T2WI at 3 T from 28 patients, 14 diabetic subjects with sensory-motor distal polyneuropathy, and 20 healthy controls. We quantified DTI-based parameters and looked at the hyperintense T2W signal at the spinal cord posterior columns. Fractional anisotropy and mean diffusivity values at C2-C3 and C3-C4 levels were compared between groups. We also compared average fractional anisotropy (mean of values at C2-C3 and C3-C4 levels). A receiver operating characteristic (ROC) curve was used to determine diagnostic accuracy of average fractional anisotropy, and we compared its sensitivity against the hyperintense signal in segregating patients from the other subjects. Mean age and disease duration were 52 ± 10 and 11.4 ± 9.3 years in the patient group. Eighteen subjects had idiopathic disease and 6 dysimmune etiology. Fractional anisotropy at C3-C4 level and average fractional anisotropy were significantly different between patients and healthy controls (p < 0.001 and <0.001) and between patients and diabetic subjects (p = 0.019 and 0.027). Average fractional anisotropy presented an area under the curve of 0.838. Moreover, it had higher sensitivity than visual detection of the hyperintense signal (0.86 vs. 0.54), particularly for patients with short disease duration. DTI-based analysis enables in vivo detection of posterior column damage in sensory neuronopathy patients and is a useful diagnostic test for this condition. It also helps the differential diagnosis between sensory neuronopathy and distal polyneuropathies. (orig.)

  13. Regional white matter lesions predict falls in patients with amnestic mild cognitive impairment and Alzheimer's disease.

    Science.gov (United States)

    Ogama, Noriko; Sakurai, Takashi; Shimizu, Atsuya; Toba, Kenji

    2014-01-01

    Preventive strategy for falls in demented elderly is a clinical challenge. From early-stage of Alzheimer's disease (AD), patients show impaired balance and gait. The purpose of this study is to determine whether regional white matter lesions (WMLs) can predict balance/gait disturbance and falls in elderly with amnestic mild cognitive impairment (aMCI) or AD. Cross-sectional. Hospital out-patient clinic. One hundred sixty-three patients diagnosed with aMCI or AD were classified into groups having experienced falls (n = 63) or not (n = 100) in the previous year. Cognition, depression, behavior and psychological symptoms of dementia, medication, and balance/gait function were evaluated. Regional WMLs were visually analyzed as periventricular hyperintensity in frontal caps, bands, and occipital caps, and as deep white matter hyperintensity in frontal, parietal, temporal, and occipital lobes, basal ganglia, thalamus, and brain stem. Brain atrophy was linearly measured. The fallers had a greater volume of WMLs and their posture/gait performance tended to be worse than nonfallers. Several WMLs in particular brain regions were closely associated with balance and gait impairment. Besides polypharmacy, periventricular hyperintensity in frontal caps and occipital WMLs were strong predictors for falls, even after potential risk factors for falls were considered. Regional white matter burden, independent of cognitive decline, correlates with balance/gait disturbance and predicts falls in elderly with aMCI and AD. Careful insight into regional WMLs on brain magnetic resonance may greatly help to diagnose demented elderly with a higher risk of falls. Copyright © 2014 American Medical Directors Association, Inc. Published by Elsevier Inc. All rights reserved.

  14. Decoupling of structural and functional brain connectivity in older adults with white matter hyperintensities

    NARCIS (Netherlands)

    Reijmer, Y. D.; Schultz, A. P.; Leemans, A.; O'Sullivan, M. J.; Gurol, M. E.; Sperling, R.; Greenberg, S. M.; Viswanathan, A.; Hedden, T.

    2015-01-01

    Age-related impairments in the default network (DN) have been related to disruptions in connecting white matter tracts. We hypothesized that the local correlation between DN structural and functional connectivity is negatively affected in the presence of global white matter injury. In 125 clinically

  15. The angular power spectrum of the diffuse gamma-ray background as a probe of Galactic dark matter substructure

    OpenAIRE

    Siegal-Gaskins, Jennifer M.

    2009-01-01

    Dark matter annihilation in Galactic substructure produces diffuse gamma-ray emission of remarkably constant intensity across the sky, and in general this signal dominates over the smooth halo signal at angles greater than a few tens of degrees from the Galactic Center. The large-scale isotropy of the emission from substructure suggests that it may be difficult to extract this Galactic dark matter signal from the extragalactic gamma-ray background. I show that dark matter substructure induces...

  16. Magnetic Resonance Imaging of Bacterial Meningoencephalitis in a Foal

    Directory of Open Access Journals (Sweden)

    Judit Viu

    2012-01-01

    Full Text Available Magnetic resonance imaging (MRI in equidae suffering meningoencephalitis (ME has not been described. The objective of this paper is to describe brain MRI findings in a foal with bacterial ME. A five-month-old, 200 kg bwt Arabian filly was referred with a history of abnormal mental status and locomotion. The filly was recumbent and obtunded, and pupillary light reflexes were sluggish, and oculocephalic movements were normally present. Ophthalmic examination revealed bilateral optic neuritis. Hematology revealed leukocytosis and neutrophilia. Cerebrospinal fluid analysis showed neutrophilic pleocytosis with intracellular bacteria. On brain MRI, there were multifocal cortical areas of mild hyperintensity on T2-weighted images (T2WI affecting both hemispheres. The lesions had ill-delineated margins, and there was loss of differentiation between gray and white matter. Diffuse hyperintensity was also identified in the left cerebellar cortex on T2WI. Neither mass effect nor cerebral midline shift were identified. On FLAIR images, the lesions were also hyperintense and, in some areas, they seemed to coalescence to form diffuse cortical areas of hyperintensity. The MRI findings described were similar to the MRI features described in cases of humans and small animals with ME. Brain MRI can be a useful diagnostic tool in foals and small-sized equidae with intracranial disease.

  17. Early pattern recognition in severe perinatal asphyxia: a prospective MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Baenziger, O. (Children' s Hospital, Univ. Zurich (Switzerland)); Martin, E. (Children' s Hospital, Univ. Zurich (Switzerland)); Steinlin, M. (Children' s Hospital, Univ. Zurich (Switzerland)); Good, M. (Children' s Hospital, Univ. Zurich (Switzerland)); Largo, R. (Children' s Hospital, Univ. Zurich (Switzerland)); Burger, R. (Children' s Hospital, Univ. Zurich (Switzerland)); Fanconi, S. (Children' s Hospital, Univ. Zurich (Switzerland)); Duc, G. (Children' s Hospital, Univ. Zurich (Switzerland)); Buchli, R. (Children' s Hospital, Univ. Zurich (Switzerland)); Rumpel, H. (Children' s Hospital, Univ. Zurich (Switzerland)); Boltshauser, E. (Children' s Hospital, Univ. Zurich (Switzerland))

    1993-01-01

    On the basis of MRI examinations in 88 neonates and infants with perinatal asphyxia, we defined 6 different patterns on T2-weighted images: pattern A-scattered hyperintensity of both hemispheres of the telencephalon with blurred border zones between cortex and white matter, indicating diffuse brain injury; pattern B-parasagittal hyperintensity extending into the corona radiata, corresponding to the watershed zones; pattern C-hyper- and hypointense lesions in thalamus and basal ganglia, which relate to haemorrhagic necrosis of iron deposition in these areas; pattern D-periventricular hyperintensity, mainly along the lateral ventricles, i.e. periventricular leukomalacia (PVL), originating from the matrix zone; pattern E-small multifocal lesions varying from hyper- to hypointense, interpreted as necrosis and haemorrhage; pattern F-periventricular centrifugal hypointense stripes in the centrum semiovale and deep white matter of the frontal and occipital lobes. Contrast was effectively inverted on T1-weighted images. Patterns A, B and C were found in 17%, 25% and 37% of patients, and patterns D, E and F in 19%, 17% and 35%, respectively. In 49 patients a combination of patterns was observed, but 30% of the initial images were normal. At follow-up, persistent abnormalities were seen in all children with patterns A and D, but in only 52% of those with pattern C. Myelination was retarded most often in patients with diffuse brain injury and PVL (patterns A and D). (orig.)

  18. Longitudinal changes in white matter disease and cognition in the first year of the Alzheimer disease neuroimaging initiative

    NARCIS (Netherlands)

    Carmichael, Owen; Schwarz, Christopher; Drucker, David; Fletcher, Evan; Harvey, Danielle; Beckett, Laurel; Jack, Clifford R.; Weiner, Michael; Decarli, Charles; Abdi, Herve; Abeliovich, Asa; Abellan van Kan, Gabor; Abner, Erin; Acharya, Deepa; Adams, Nicholas; Adler, Daniel; Agrusti, Antonella; Agyemang, Alex; Ahdidan, Jamila; Ahn, Jae Eun; Aisen, Paul; Aksu, Yaman; Al-Akhras, Mousa; Alarcon, Marcelo; Alberca, Roman; Alexander, Gene; Alexander, Daniel; Almeida, Fabio; Anand, Rishi; Anand, Shyam; Andrew, Marilee; Anjum, Ayesha; Aoyama, Eiji; Ard, Michael Colin; Arfanakis, Konstantinos; Armor, Tom; Arnold, Steven; Asatryan, Albert; Ashe-McNalley, Cody; Ashiga, Hirokazu; Assareh, Arezoo; Aubry, Florent; Avants, Brian; Avinash, Gopal; Awasthi, Sukrati; Ayan-Oshodi, Mosun; Bagci, Ulas; Bai, Shuyang; Baker, John; Banks, Sarah; Bard, Jonathan; Barnes, Josephine; Barret, Olivier; Bartzokis, George; Barua, Neil; Bauer, Corinna; Becker, James; Bednar, Martin; Beg, Mirza Faisal; Bek, Stephan; Bernard, Charlotte; Bertram, Lars; Bhagwagar, Zubin; Biffi, Alessandro; Bilgic, Basar; Bishnoi, Mahesh; Bishop, Courtney; Bittner, Daniel; Black, Ronald; Blennow, Kaj; Bogorodzki, Piotr; Bokde, Arun; Bonner-Jackson, Aaron; Boppana, Madhu; Bourgeat, Pierrick; Bowes, Mike; Bowman, Gene; Bowman, DuBois; Braskie, Meredith; Brewer, James; Brickman, Adam; Broadbent, Steve; Brooks, David; Browndyke, Jeffrey; Bruat, Vanessa; Brunton, Simon; Buchert, Ralph; Buchsbaum, Monte; Buckley, Chris; Burger, Cyrill; Burns, Jeffrey; Burton, David; Butman, John; Cabeza, Rafael; Cairns, Nigel; Callhoff, Johanna; Calvini, Piero; Campbell, Aaron; Cantillon, Marc; Capella, Heraldo; Cardona-Sanclemente, Luis Eduardo; Carle, Adam; Carmasin, Jeremy; Carranza-Ath, Fredy; Casanova, Ramon; Cash, David; Cella, Massimo; Celsis, Pierre; Chan, Lung Tat Andrew; Chaney, Megan; Chanu, Pascal; Chao, Linda; Charil, Arnaud; Chemali, Zeina; Chen, Baojiang; Chen, Kewei; Chen, Ting; Chen, Minhua; Chen, Gennan; Chen, Rong; Cheng, Wei-Chen; Chertkow, Howard; Chiang, Gloria; Chiba, Koji; Chisholm, Jane; Cho, Youngsang; Choe, John; Choubey, Suresh; Christensen, Anette Luther; Clark, Chris; Clark, David; Clarkson, Matt; Clayton, David; Clunie, David; Coimbra, Alexandre; Compton, David; Crane, Paul; Crans, Gerald; Croop, Robert; Crowther, Daniel; Crum, William; Cui, Yue; Curry, Charles; Curtis, Steven; Cutter, Gary; Daiello, Lori; Dake, Michael; Dale, Anders; Damato, Vito Domenico; Darby, Eveleen; Darkner, Sune; Davatzikos, Christos; Dave, Jay; David, Renaud; Davidson, Julie; de Bruijne, Marleen; de Meyer, Geert; de Nunzio, Giorgio; de Santi, Susan; Dechairo, Bryan; DeDuck, Kristina; Dejkam, Arsalan; Delfino, Manuel; Delpassand, Ebrahim; Deniz, Oscar; Denney, Douglas; DeOrchis, Vincent; Depy Carron, Delphine; deToledo-Morrell, Leyla; Devanand, Davangere; Devanarayan, Viswanath; Diaz, Gloria; Diaz-Arrastia, Ramon; Dickerson, Bradford; Dinov, Ivo; Dodge, Hiroko; Donohue, Michael; Dowling, Maritza; Drzezga, Alex; Duan, Xujun; Duchesne, Simon; Duff, Kevin; Dukart, Jurgen; Durazzo, Timothy; Dykstra, Kevin; Earl, Nancy; Edula, Goutham; Ekin, Ahmet; Engelman, Corinne; Epstein, Noam; Erten-Lyons, Deniz; Eskildsen, Simon; Falcone, Guido; Fan, Yong; Farnum, Michael; Farrer, Lindsay; Farzan, Ali; Feldman, Howard; Feng, Yan; Fennema-Notestine, Christine; Fernandes, Michel; Fernandez, Elsa; Ferrarini, Luca; Ferreira, Luiz; Ferrer, Eugene; Figurski, Michal; Filipovych, Roman; Finch, Stephen; Finlay, Daniel; Fiot, Jean-Baptiste; Flenniken, Derek; Fletcher, P. Thomas; Flynn Longmire, Crystal; Forman, Mark; Forsythe, Alan; Fox-Bosetti, Sabrina; Francis, Alexander L.; Franco-Villalobos, Conrado; Franko, Edit; Freeman, Stefanie; Friedrich, Christoph M.; Friesenhahn, Michel; Frings, Lars; Frisoni, Giovanni; Fritzsche, Klaus; Fujimoto, Yoko; Fujiwara, Ken; Fullerton, Terence; Furney, Simon; Gallins, Paul; Gamst, Anthony; Gan, Ke; Garcia, Maria Teresa; Garcia-Linares, Antonio; Garg, Gaurav; Gaser, Christian; Gastineau, Edward; Gavidia, Giovana; Gazdzinski, Stefan; Ge, Qi; Gemme, Gianluca; German, Dwight; Ghassabi, Zeinab; Gil, Juan E.; Gill, Ryan; Gitelman, Darren; Gleason, Carey; Godbey, Michael; Goghari, Vina; Gold, Michael; Goldberg, Terry; Gomeni, Roberto; Gong, Shangwenyan; Gonzales, Celedon; Gordon, Brian; Gorriz, Juan Manuel; Grachev, Igor; Grandey, Emily; Grasela, Thaddeus; Gratt, Jeremy; Gray, Katherine; Greenberg, Barry; Gregg, Keith; Gregory, Erik; Greicius, Michael; Greve, Douglas; Grill, Joshua; Gross, Alan; Guo, Lianghao; Guo, Hongbin; Guo, Jeffrey; Habeck, Christian; Hai, Yizhen; Haight, Thaddeus; Hakansson, Kristina; Hammarstrom, Per; Hampel, Harald; Han, Tony; Han, Jian; Hanif, Muhammad; Hanna, Yousef; Hardy, Peter; Hasan, Md Kamrul; Hazart, Aurelien; Hazel, James; He, Yong; He, Huiguang; Head, Denise; Heckemann, Rolf; Heidebrink, Judith; Henderson, David; Henrard, Sebastien; Herholz, Karl; Hernandez, Monica; Hess, Christopher; Hobart, Jeremy; Hoffman, John; Holder, Daniel; Honigberg, Lee; Horsfield, Mark; Hsu, Wei-Wen; Hsu, Ailing; Hu, Zhenghui; Hu, Zhiwei; Hu, Xiaolan; Hu, William; Huang, Shu-Pang; Huang, Chun-Jung; Huang, Fude; Huang, Yifan; Huang, Juebin; Huang, Chingwen; Hubbard, Rebecca; Huentelman, Matthew; Hui, Shen; Huppertz, Hans-Jurgen; Hurko, Orest; Hurt, Stephen; Huyck, Susan; Hwang, Scott; Hyun, JungMoon; Ifeachor, Emmanuel; Iglesias, Martina; Ikari, Yasuhiko; Immermann, Fred; Inoue, Lurdes; Insel, Philip; Irizarry, Michael; Irungu, Benson mwangi; Ishibashi, Taro; Ishii, Kenji; Ismail, Shahina; Ito, Kaori; Ito, Momoyo; Iwatsubo, Takeshi; Iyer, Madhumitha; Jacobson, Mark; Jacobson, Alex; Jafari, Aria; Jafari-Khouzani, Kourosh; Jaffe, Carl; Jagust, William; Jara, Hernan; Jaros, Mark; Jefferson, Angela; Jiang, Tianzi; Johnson, David K.; Juengling, Freimut; Juh, Rahyeong; Julin, Per; Bhaskar, Uday; Kadish, Bill; Kahle-Wrobleski, Kristin; Kallam, Hanimi Reddy; Kalpathy-Cramer, Jayashree; Karageorgiou, Elissaios; Karantzoulis, Stella; Karasev, Peter; Kauwe, John; Kawakami, Hirofumi; Kazimipoor, Borhan; Kelleher, Thomas; Kennedy, Richard; Kerr, Douglas; Kerrouche, Nacer; Khalil, Iya; Khalil, Andre; Khatry, Deepak; Kihel, Badra; Killeen, Neil; Killiany, Ron; Kim, Hyewon; Kim, Heeyoung; Kim, Yeonhee; Kim, Jong Hun; Kimberg, Daniel; Kimura, Tokunori; King, Richard; Kirby, Justin; Kita, Hiroshi; Klimas, Michael; Klopfenstein, Erin; Kobayashi, Dione; Koikkalainen, Juha; Kokomoor, Anders; Kolasny, Anthony; Kondo, Yusuke; Koppel, Jeremy; Korolev, Igor; Kotran, Nickolas; Kouassi, Alex; Koutsouleris, Nikolaos; Kozma, Lynn; Kramer, Joel; Kratzer, Martina; Kuceyeski, Amy; Kuhn, Felix Pierre; Kulkarni, Mauktik; Kumar, Sreedhar; Kuo, Hsun Ting; Kuo, Julie; Kurosawa, Ken; Kwon, Oh Hun; Laforet, Genevieve; Lai, Song; Lakatos, Anita; Landau, Susan; Landen, Jaren; Lane, Richard; Langbaum, Jessica; Lanius, Vivian; Lavault, Romain; Laxamana, Joel; Le, Trung; Leahy, Richard; Lee, Noah; Lee, Vita; Lee, Joseph H.; Lee, Jong-Min; Lee, Dongsoo; Lee, Junyoung; Lefkimmiatis, Stamatis; Lemaitre, Herve; Lenz, Robert; Lester, Gayle; Levey, Allan; Li, Rui; Li, Wenjun; Li, Shanshan; Li, Lexin; Li, Shi-jiang; Li, Gang; Li, Lin; Li, Yi; Li, Jinhe; Li, Chin-Shang; Liang, Peipeng; Liang, Lichen; Liao, Yuan-Lin; Lin, Mingkuan; Lin, Lan; Lin, Ling-chih; Liu, Tao; Liu, Meijie; Liu, Yuan; Liu, Dazhong; Liu, Pu; Liu, Songling; Liu, Xiuwen; Liu, Tianming; Lo, Raymond; Logovinsky, Veronika; Lois, Augusto; Long, Xiaojing; Long, Ziyi; Looi, Jeffrey; Lu, Yuan; Lu, Po-Haong; Lukic, Ana; Lull, Juan J.; Lynch, John; Ma, Lei; Mackin, Scott; Magda, Sebastian; Maglio, Silvio; Mak, Henry Ka-Fung; Malave, Vicente; Mandal, Pravat; Mangin, Jean-Francois; Manohar, Deepak; Mansouri, Chemseddine; Mantri, Ninad; Manzour, Amir; Marambaud, Philippe; Marchewka, Artur; Marek, Kenneth; Markind, Samuel; Marshall, Gad; Martin, Jacob; Mather, Mara; Mathis, Chester; Matoug, Sofia; Matsuo, Yoshiyuki; Matthews, Dawn; Mayo, Agustin; McEvoy, Linda; McGeown, William; McIntyre, John; McQuail, Joseph; Meadowcroft, Mark; Meda, Shashwath; Mehta, Nirav; Mele, Valeria; Mendonca, Brian; Menendez, Manuel; Meredith, Jere; Merrill, David; Mesulam, Marek-Marsel; Meyer, Carsten; Mez, Jesse; Mickael, Guedj; Miftahof, Roustem; Mikhno, Arthur; Miller, David; Min, Ye; Miri, Roham; Mirza, Mubeena; Mitsis, Effie; Mohan, Ananth; Monno, Laura; Montana, Giovanni; Moore, Dana; Birgani, Parmida Moradi; Moratal, David; Morimoto, Bruce; Mortamet, Benedicte; Motyl, Rafal; Mueller, Notger; Mukherjee, Shubhabrata; Mulder, Emma; Murphy, Michael; Murray, Brian; Musiek, Erik; Myers, Amanda; Najafi, Shahla; Nazeri, Arash; Nettiksimmons, Jasmine; Neu, Scott; Neves, Simone; Ng, Yen-Bee; Nguyen, Danh; Nguyen, Nghi; Nguyen Xuan, Tuong; Nielsen, Casper; Nuneez Benjumea, Francisco; O'Neil, Alison; Obisesan, Thomas; Oh, Dong Hoon; Oh, Joonmi; Okonkwo, Ozioma; Olde Rikkert, Marcel; Ollesch, Julian; Olmos, Salvador; Ostrowitzki, Susanne; Oswald, Annahita; Ott, Brian; Ourselin, Sebastien; Ouyang, Gaoxiang; Paiva, Renata; Pan, Zhifang; Pande, Yogesh; Pardoe, Heath; Park, Kee Hyung; Park, Hyunjin; Parsey, Ramin; Parveen, Riswana; Paskavitz, James; Patel, Yogen; Patil, Manasi; Paul, Robert; Pawlak, Mikolaj; Peavy, Guerry; Peng, Yahong; Pepin, Jean louis; Perea, Rodrigo; Perneczky, Robert; Petitti, Diana; Petrella, Jeffrey; Peyrat, Jean-Marc; Pezoa, Jorge; Pham, Chi-Tuan; Phillips, Nicole; Piovezan, Mauro; Podhorski, Adam; Pollari, Mika; Pontecorvo, Michael; Poppenk, Jordan; Posner, Holly; Potkin, Steven; Poulin, Stephane; Prasad, Gautam; Prenger, Kurt; Prieto, Elena; Prince, Jerry; Puchakayala, Shashidhar Reddy; Qin, Wei; Qiu, Ruolun; Qiu, Wendy; Qiu, Anqi; Qualls, Constance Dean; Rabie, Huwaida; Rajeesh, Rajeesh; Rajeesh, J. Rajeesh; Rallabandi, V. P. Subramanyam; Ramage, Amy; Randolph, Christopher; Raniga, Parnesh; Rao, Divya; Rao, Anil; Raubertas, Richard; Ray, Debashis; Razak, Hana; Redolfi, Alberto; Reid, Andrew; Reilhac, Anthonin; Reinsberger, Claus; Restrepo, Lucas; Retico, Alessandra; Rezaeitabar, Yousef; Richards, John; Richter, Mirco; Riddle, William; Ries, Michele; Rincon, Mariano; Rischall, Matt; Robieson, Weining; Rocha-Rego, Vanessa; Rogalski, Emily; Rogers, Elizabeth; Rojas, Ignacio; Romero, Klaus; Rosand, Jonathan; Rosen, Ori; Rosen, Allyson; Rosenberg, Paul; Ross, David; Ross, Joel; Rousseau, Francois; Rowe, Christopher; Rubin, Daniel; Ruiz, Agustin; Rusinek, Henry; Ryan, Laurie; Saad, Ahmed; Sabbagh, Marway; Sabuncu, Mert; Sachs, Michael; Sacuiu, Simona; Sadeghi, Ali; Said, Yasmine; Saint-Aubert, Laure; Sakata, Muneyuki; Salat, David; Salmon, David; Salomi, Sharmila; Salter, Hugh; Samwald, Matthias; Sanchez, Luciano; Sanjo, Nobuo; Sankaranarayanan, Preethi; Sato, Shinji; Sato, Hajime; Saumier, Daniel; Savio, Alexandre; Sawada, Ikuhisa; Saykin, Andrew; Schaffer, J. David; Scharre, Douglas; Schlosser, Gretchen; Schmand, Ben; Schmansky, Nick; Schmidt, Mark; Schneider, Lon; Schramm, Hauke; Schuerch, Markus; Schwartz, Eben; Schwartz, Craig; Schwarz, Adam; Seethamraju, Ravi; Seixas, Flavio; Selnes, Per; Senjem, Matthew; Senlin, Wang; Seo, Sang Won; Sethuraman, Gopalan; Sevigny, Jeffrey; Sfikas, Giorgos; Shahbaba, Babak; Shams, Soheil; Shankle, William; Shattuck, David; Shaw, Leslie; Sheela, Jaba; Shen, Weijia; Shera, David; Sherman, John; Sherman, Michelle; Sherva, Richard; Shimizu, Keiji; Shuler, Catherine; Shulman, Joshua; Siegel, Rene; Siemers, Eric; Silveira, Margarida; Silver, Michael; Silverman, Daniel; Simmons, Andy; Simpson, Ivor; Singh, Simer Preet; Singh, Nikhil; Siuciak, Judy; Sjogren, Niclas; Skup, Martha; Small, Gary; Smith, Benjamin; Smith, Michael; Smith, Charles; Smyth, Timothy; Snow, Sarah; Soares, Holly; Soldea, Octavian; Solomon, Paul; Solomon, Alan; Song, Mingli; Song, Changhong; Sorensen, Greg; Soudah, Eduardo; Spampinato, Maria Vittoria; Spenger, Christian; Sperling, Reisa; Spiegel, Rene; Spies, Lothar; Squarcia, Sandro; Squire, Larry; Staff, Roger; Stern, Yaakov; Strittmatter, Stephen; Styren, Scot; Sugishita, Morihiro; Sugishita, Kazuyuki; Sukkar, Rafid; Sun, Jia; Sun, Yu; Sundell, Karen; Suri, Muhammad; Swan, Melanie; Takagi, Toshihisa; Takahasi, Tetsuhiko; Takeuchi, Tomoko; Tang, Songyuan; Tanner, William; Tao, Wenwen; Tao, Dacheng; Tariot, Pierre; Tarjoman, Mana; Tatsuoka, Curtis; Taylor-Reinwald, Lisa; Terlizzi, Rita; Thiele, Frank; Thomas, Ronald; Thomas, Benjamin; Thompson, Paul; Thompson, Wesley; Thornton-Wells, Tricia; Thurfjell, Lennart; Titeux, Laurence; Tolli, Tuomas; Toma, Ahmed; Tomita, Naoki; Toro, Roberto; Tosun, Duygu; Toussaint, Paule; Toyoshiba, Hiroyoshi; Tractenberg, Rochelle E.; Trittschuh, Emily; Truran, Diana; Tsechpenakis, Gavriil; Tucker-Drob, Elliot; Tung, Joyce; Uesugi, Humito; Ullrich, Lauren; Umadevi Venkataraju, Kannan; Umar, Nisser; Uzunbas, Gokhan; Valdivia, Fernando; van Horn, John; van Leemput, Koen; van Train, Kenneth; van Zeeland, Ashley; Vargas, Gabriel; Vasanawala, Minal; Vemuri, Prashanthi; Verwaerde, Philippe; Videbaek, Charlotte; Vidoni, Eric; Vigneron, Vincent; Villanueva-Meyer, Javier; Visser, Pieter Jelle; Vitolo, Ottavio; Vlassenko, Andrei; Volkau, Ihar; Vounou, Maria; Wade, Sara; Walhovd, Kristine B.; Wallace, Douglas; Wan, Hong; Wang, Angela; Wang, Li-San; Wang, Yongmei Michelle; Wang, Yaping; Wang, Alex; Wang, Lubin; Wang, Yalin; Wang, Tiger; Wang, Yue; Wang, Huanli; Wang, Huali; Ward, Michael; Warfield, Simon; Waring, Stephen; Webb, David; Wei, Lili; Wen, Shu-Hui; Wenjing, Li; Wenzel, Fabian; Westlye, Lars T.; Whitcher, Brandon; Whitwell, Jennifer; WilliamFaltaos, Demiana; Williams, David; Wilmot, Beth; Wingo, Thomas; Winkler, Andreas; Wiste, Heather; Wolfson, Tanya; Wolke, Ira; Wolz, Robin; Woo, Jongwook; Woo, Ellen; Woods, Lynn; Worth, Andrew; Worth, Eric; Wouters, Hans; Wu, Liang; Wu, Xiaoling; Wu, Yi Gen; Wu, Teresa; Wyman, Bradley; Wyss-Coray, Tony; Xiao, Liu; Xu, Guofan; Xu, Jun; Yamane, Tomohiko; Yamashita, Fumio; Yamazawa, Maki; Yan, Yunyi; Yan, Pingkun; Yang, Qing X.; Yang, Zhitong; Ye, Byoung Seok; Ye, Jieping; Yee, Laura; Yesavage, Jerome; Yip, WaiKuan; Yoo, Bongin; Yuan, Kai; Yushkevich, Paul; Zagorodnov, Vitali; Zagorski, Michael; Zawadzki, Rezi; Zeitzer, Jamie; Zhang, Linda; Zhang, Lijun; Zhang, Tianhao; Zhang, Huixiong; Zhang, Bin; Zhang, Kurt; Zhao, Qinying; Zhao, Peng; Zhen, Xiantong; Zheng, Yuanjie; Zhijun, Yao; Zhou, Sheng; Zhou, Bin; Zhou, Luping; Zhu, Wanlin; Zhu, Hongtu; Zou, Heng

    2010-01-01

    To evaluate relationships between magnetic resonance imaging (MRI)-based measures of white matter hyperintensities (WMHs), measured at baseline and longitudinally, and 1-year cognitive decline using a large convenience sample in a clinical trial design with a relatively mild profile of

  19. Mapping of ApoE4 related white matter damage using diffusion MRI

    Science.gov (United States)

    Tsao, Sinchai; Gajawelli, Niharika; Hwang, Darryl H.; Kriger, Stephen; Law, Meng; Chui, Helena; Weiner, Michael; Lepore, Natasha

    2014-04-01

    ApoliopoproteinE Ɛ4 (ApoE-Ɛ4) polymorphism is the most well known genetic risk factor for developing Alzheimers Disease. The exact mechanism through which ApoE 4 increases AD risk is not fully known, but may be related to decreased clearance and increased oligomerization of Aβ. By making measurements of white matter integrity via diffusion MR and correlating the metrics in a voxel-based statistical analysis with ApoE-Ɛ4 genotype (whilst controlling for vascular risk factor, gender, cognitive status and age) we are able to identify changes in white matter associated with carrying an ApoE Ɛ4 allele. We found potentially significant regions (Puncorrected cognitive decline via a pathway in dependent of normal aging and acute insults that can be measured by CDR and Framingham Coronary Risk Score (FCRS).

  20. Differentiation of benign osteoporotic and neoplastic vertebral compression fractures with a diffusion-weighted, steady-state free precession sequence

    International Nuclear Information System (INIS)

    Baur, A.; Huber, A.; Nikolaou, K.; Staebler, A.; Reiser, M.; Duerr, H.R.

    2002-01-01

    Purpose: To evaluate the diagnosic accuracy of a diffusion-weigthed, steady-state free precession (SSFP) sequence for the differentiation of acute benign osteoporotic and neoplastic vertebral compression fractures. Methods: 85 patients with 102 vertebral compression fractures were examined with MR imaging using a spine array surface coil (Siemens, Vision, 1.5 Tesla). The following sequences were performed in sagittal orientation: T 1 -weighted spin echo (SE), short-tau inversion recovery (STIR) and a diffusion-weighted SSFP sequence (TR=25 msec, diffusion pulse length δ=3 msec). The SSFP images were evaluated qualitatively on a 5-grade scale from strongly hypointense to strongly hyperintense. Quantitative analysis was performed with region of interest measurements (ROI) and calculation of a bone marrow ratio. Results: 60 fractures were due to osteoporosis and 42 fractures were caused by malignancy. 'Hyperintensity' in a vertebral fracture on a SSFP sequence provided a sensitivity of 100% and a specificity of 93%. The positive predictive value was 91%, the negative predictive value was 100%. Quantitative analysis of the bone marrow ratio showed a statistically significant difference between the osteoporosis and the tumor group (p [de

  1. Understanding the direction of the relationship between white matter hyperintensities of vascular origin, sleep quality, and chronic kidney disease-Results from the Atahualpa Project.

    Science.gov (United States)

    Del Brutto, Oscar H; Mera, Robertino M

    2018-02-01

    The burden of cerebral small vessel disease, sleep disorders, and chronic kidney disease is on the rise in remote rural settings. However, information on potential links between these conditions is limited. We aimed to assess the relationships between these conditions in community-dwelling older adults living in rural Ecuador. Atahualpa residents aged ≥60 years were offered a brain MRI. A venous blood sample was obtained for serum creatinine determination. Baseline interviews and procedures were directed to assess demographics, cardiovascular risk factors, and sleep quality. Using generalized structural equation modeling (GSEM), we assessed the associations between white matter hyperintensities (WMH) of vascular origin, sleep quality and kidney function, as well as the directions of the relationships between these variables. Of 423 candidates, 314 (74%) were enrolled. Moderate-to-severe WMH were noticed in 74 (24%) individuals, poor sleep quality in 101 (31%), and moderate-to-severe chronic kidney disease in 28 (9%). GSEM showed that the direction of the effect was from kidney function to WMH and from the latter to sleep quality. Of independent variables investigated, worse kidney function was associated with age, high glucose levels and male sex. WMH was associated with cholesterol blood levels, blood pressure, level of education and severe edentulism. Poor sleep quality was associated with poor physical activity. This population based study shows that chronic kidney disease is associated with increased severity of WMH, which, in turn, is associated with a poor sleep quality. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Segmentation of white matter hyperintensities using convolutional neural networks with global spatial information in routine clinical brain MRI with none or mild vascular pathology.

    Science.gov (United States)

    Rachmadi, Muhammad Febrian; Valdés-Hernández, Maria Del C; Agan, Maria Leonora Fatimah; Di Perri, Carol; Komura, Taku

    2018-06-01

    We propose an adaptation of a convolutional neural network (CNN) scheme proposed for segmenting brain lesions with considerable mass-effect, to segment white matter hyperintensities (WMH) characteristic of brains with none or mild vascular pathology in routine clinical brain magnetic resonance images (MRI). This is a rather difficult segmentation problem because of the small area (i.e., volume) of the WMH and their similarity to non-pathological brain tissue. We investigate the effectiveness of the 2D CNN scheme by comparing its performance against those obtained from another deep learning approach: Deep Boltzmann Machine (DBM), two conventional machine learning approaches: Support Vector Machine (SVM) and Random Forest (RF), and a public toolbox: Lesion Segmentation Tool (LST), all reported to be useful for segmenting WMH in MRI. We also introduce a way to incorporate spatial information in convolution level of CNN for WMH segmentation named global spatial information (GSI). Analysis of covariance corroborated known associations between WMH progression, as assessed by all methods evaluated, and demographic and clinical data. Deep learning algorithms outperform conventional machine learning algorithms by excluding MRI artefacts and pathologies that appear similar to WMH. Our proposed approach of incorporating GSI also successfully helped CNN to achieve better automatic WMH segmentation regardless of network's settings tested. The mean Dice Similarity Coefficient (DSC) values for LST-LGA, SVM, RF, DBM, CNN and CNN-GSI were 0.2963, 0.1194, 0.1633, 0.3264, 0.5359 and 5389 respectively. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

  3. Diffusion tensor imaging of brain white matter in Huntington gene mutation individuals

    Directory of Open Access Journals (Sweden)

    Roberta Arb Saba

    Full Text Available ABSTRACT Objective To evaluate the role of the involvement of white matter tracts in huntingtin gene mutation patients as a potential biomarker of the progression of the disease. Methods We evaluated 34 participants (11 symptomatic huntingtin gene mutation, 12 presymptomatic huntingtin gene mutation, and 11 controls. We performed brain magnetic resonance imaging to assess white matter integrity using diffusion tensor imaging, with measurement of fractional anisotropy. Results We observed a significant decrease of fractional anisotropy in the cortical spinal tracts, corona radiate, corpus callosum, external capsule, thalamic radiations, superior and inferior longitudinal fasciculus, and inferior frontal-occipital fasciculus in the Huntington disease group compared to the control and presymptomatic groups. Reduction of fractional anisotropy is indicative of a degenerative process and axonal loss. There was no statistically significant difference between the presymptomatic and control groups. Conclusion White matter integrity is affected in huntingtin gene mutation symptomatic individuals, but other studies with larger samples are required to assess its usefulness in the progression of the neurodegenerative process.

  4. Investigating the capability to resolve complex white matter structures with high b-value diffusion magnetic resonance imaging on the MGH-USC Connectom scanner.

    Science.gov (United States)

    Fan, Qiuyun; Nummenmaa, Aapo; Witzel, Thomas; Zanzonico, Roberta; Keil, Boris; Cauley, Stephen; Polimeni, Jonathan R; Tisdall, Dylan; Van Dijk, Koene R A; Buckner, Randy L; Wedeen, Van J; Rosen, Bruce R; Wald, Lawrence L

    2014-11-01

    One of the major goals of the NIH Blueprint Human Connectome Project was to map and quantify the white matter connections in the brain using diffusion tractography. Given the prevalence of complex white matter structures, the capability of resolving local white matter geometries with multiple crossings in the diffusion magnetic resonance imaging (dMRI) data is critical. Increasing b-value has been suggested for delineation of the finer details of the orientation distribution function (ODF). Although increased gradient strength and duration increase sensitivity to highly restricted intra-axonal water, gradient strength limitations require longer echo times (TE) to accommodate the increased diffusion encoding times needed to achieve a higher b-value, exponentially lowering the signal-to-noise ratio of the acquisition. To mitigate this effect, the MGH-USC Connectom scanner was built with 300 mT/m gradients, which can significantly reduce the TE of high b-value diffusion imaging. Here we report comparisons performed across b-values based on q-ball ODF metrics to investigate whether high b-value diffusion imaging on the Connectom scanner can improve resolving complex white matter structures. The q-ball ODF features became sharper as the b-value increased, with increased power fraction in higher order spherical harmonic series of the ODF and increased peak heights relative to the overall size of the ODF. Crossing structures were detected in an increasingly larger fraction of white matter voxels and the spatial distribution of two-way and three-way crossing structures was largely consistent with known anatomy. Results indicate that dMRI with high diffusion encoding on the Connectom system is a promising tool to better characterize, and ultimately understand, the underlying structural organization and motifs in the human brain.

  5. Callosal hyperintensities and gait speed gain from two types of mobility interventions in older adults.

    Science.gov (United States)

    Nadkarni, Neelesh K; Perera, Subashan; Studenski, Stephanie A; Rosano, Caterina; Aizenstein, Howard J; VanSwearingen, Jessie M

    2015-06-01

    To assess whether the volume of callosal hyperintensities in the genu and splenium of older adults with mobility impairment is differentially associated with the degree of gain in gait speed after 2 types of gait interventions. Single-blind randomized controlled trial of 2 types of gait exercises in older adults. Research center in an academic institution. Ambulatory adults (N=44) aged ≥65 years with a slow and variable gait. Twelve-week physical therapist-guided trial of a conventional walking, endurance, balance, and strength (WEBS) intervention (n=20) versus a timing and coordination of gait (TC) intervention (n=22). Gain in gait speed after the intervention and its relation to callosal hyperintensities in the genu and splenium of the corpus callosum. Gait speed improved in both the WEBS group (mean change, 0.16m/s) and the TC group (mean change, 0.21m/s; both PMobility impaired older adults with genual hyperintensities may benefit from a rehabilitation program focused on motor skill learning rather than on strength and endurance training. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  6. Intra- and interhemispheric variations of diffusivity in subcortical white matter in normal human brain

    International Nuclear Information System (INIS)

    Yoshiura, Takashi; Noguchi, Tomoyuki; Hiwatashi, Akio; Togao, Osamu; Yamashita, Koji; Nagao, Eiki; Kamano, Hironori; Honda, Hiroshi

    2010-01-01

    Our purpose was to reveal potential regional variations in water molecular diffusivity within each cerebral hemisphere and across the right and left hemispheres. Diffusion-weighted images of 44 healthy right-handed adult male subjects were obtained using a diffusion tensor imaging sequence. Mean diffusivity (MD) values in subcortical white matter (WM) within 39 regions in each hemisphere were measured using an automated method. Intrahemispheric comparisons of MDs in subcortical WM were performed among six brain regions (frontal, parietal, occipital and temporal lobes and pre- and postcentral gyri). Interhemispheric comparisons of MDs were performed between the right and left counterparts of the 39 regions. In both hemispheres, diffusivity in the precentral gyrus was lower than those in other regions, while diffusivity in the parietal lobe was higher than others. MD asymmetry in which the left was lower than the right was found in the parietal lobe, middle occipital gyrus, and medial and orbital aspects of the frontal lobe. The converse asymmetry was revealed in the frontal operculum, supplementary motor cortex, temporal lobe, limbic cortices, precuneus and cuneus. Our results revealed significant intra- and interhemispheric regional variations in MD in subcortical WM, which may be related to different densities of axons and myelin sheaths. (orig.)

  7. Intra- and interhemispheric variations of diffusivity in subcortical white matter in normal human brain

    Energy Technology Data Exchange (ETDEWEB)

    Yoshiura, Takashi; Noguchi, Tomoyuki; Hiwatashi, Akio; Togao, Osamu; Yamashita, Koji; Nagao, Eiki; Kamano, Hironori; Honda, Hiroshi [Kyushu University, Department of Clinical Radiology, Graduate School of Medical Sciences, Fukuoka (Japan)

    2010-01-15

    Our purpose was to reveal potential regional variations in water molecular diffusivity within each cerebral hemisphere and across the right and left hemispheres. Diffusion-weighted images of 44 healthy right-handed adult male subjects were obtained using a diffusion tensor imaging sequence. Mean diffusivity (MD) values in subcortical white matter (WM) within 39 regions in each hemisphere were measured using an automated method. Intrahemispheric comparisons of MDs in subcortical WM were performed among six brain regions (frontal, parietal, occipital and temporal lobes and pre- and postcentral gyri). Interhemispheric comparisons of MDs were performed between the right and left counterparts of the 39 regions. In both hemispheres, diffusivity in the precentral gyrus was lower than those in other regions, while diffusivity in the parietal lobe was higher than others. MD asymmetry in which the left was lower than the right was found in the parietal lobe, middle occipital gyrus, and medial and orbital aspects of the frontal lobe. The converse asymmetry was revealed in the frontal operculum, supplementary motor cortex, temporal lobe, limbic cortices, precuneus and cuneus. Our results revealed significant intra- and interhemispheric regional variations in MD in subcortical WM, which may be related to different densities of axons and myelin sheaths. (orig.)

  8. Three-dimensional white matter tractography by diffusion tensor imaging in ischaemic stroke involving the corticospinal tract

    International Nuclear Information System (INIS)

    Kunimatsu, A.; Aoki, S.; Masutani, Y.; Abe, O.; Mori, H.; Ohtomo, K.

    2003-01-01

    Diffusion tensor MR imaging (DTI) provides information on diffusion anisotropy, which can be expressed with three-dimensional (3D) white matter tractography. We used 3D white matter tractography to show the corticospinal tract in eight patients with acute or early subacute ischaemic stroke involving the posterior limb of the internal capsule or corona radiata and to assess involvement of the tract. Infarcts and the tract were shown simultaneously, providing information on their spatial relationships. In five of the eight patients, 3D fibre tract maps showed the corticospinal tract in close proximity to the infarct but not to pass through it. All these patients recovered well, with maximum improvement from the lowest score on manual muscle testing (MMT) up to the full score through rehabilitation. In the other three patients the corticospinal tract was shown running through the infarct; reduction in MMT did not necessarily improve favourably or last longer, other than in one patient. As 3D white matter tractography can show spatial relationships between the corticospinal tract and an infarct, it might be helpful in prognosis of gross motor function. (orig.)

  9. Three-dimensional white matter tractography by diffusion tensor imaging in ischaemic stroke involving the corticospinal tract

    Energy Technology Data Exchange (ETDEWEB)

    Kunimatsu, A.; Aoki, S.; Masutani, Y.; Abe, O.; Mori, H.; Ohtomo, K. [Department of Radiology, Graduate School of Medicine, Tokyo University, 7-3-1 Hongo, Bunkyo-ku, 113-8655, Tokyo (Japan)

    2003-08-01

    Diffusion tensor MR imaging (DTI) provides information on diffusion anisotropy, which can be expressed with three-dimensional (3D) white matter tractography. We used 3D white matter tractography to show the corticospinal tract in eight patients with acute or early subacute ischaemic stroke involving the posterior limb of the internal capsule or corona radiata and to assess involvement of the tract. Infarcts and the tract were shown simultaneously, providing information on their spatial relationships. In five of the eight patients, 3D fibre tract maps showed the corticospinal tract in close proximity to the infarct but not to pass through it. All these patients recovered well, with maximum improvement from the lowest score on manual muscle testing (MMT) up to the full score through rehabilitation. In the other three patients the corticospinal tract was shown running through the infarct; reduction in MMT did not necessarily improve favourably or last longer, other than in one patient. As 3D white matter tractography can show spatial relationships between the corticospinal tract and an infarct, it might be helpful in prognosis of gross motor function. (orig.)

  10. Early MR detection of cortical and subcortical hypoxic-ischemic encephalopathy in full-term-infants

    International Nuclear Information System (INIS)

    Christophe, C.; Clercx, A.; Blum, D.; Hasaerts, D.; Segebarth, C.; Perlmutter, N.

    1994-01-01

    Four observations illustrate the potential of MR imaging in the early depiction of multiple types of neuropathologic lesions which may coexist in the full-term newborn, upon severe hypoxic-ischemic encephalopathy (HIE). In particular, diffuse, postnatal involvement of cerebral cortex and subcortical white matter (WM) is demonstrated. Cortical hyperintensity on both proton-density- and T1-weighted images is probably related to cellular necrosis which is distributed diffusely or parasigattally. Hyperintense, frontal, subcortical WM edging on proton-density-weighted images results from the increase of water concentration, induced either by infract or by edema. Diffuse WM areas of low intensity on T1-weighted images and of high intensity on T2-weighted images are presumably related to cytotoxic and/or vasogenic edema, proportional to the underlying damaged tissues. On follow-up MR examinations, several months later, the importance of cortical atrophy and of the myelination delay appeared related to the importance of the lesions detected during the post-natal period. (orig.)

  11. White Matter Compromise of Callosal and Subcortical Fiber Tracts in Children with Autism Spectrum Disorder: A Diffusion Tensor Imaging Study

    Science.gov (United States)

    Shukla, Dinesh K.; Keehn, Brandon; Lincoln, Alan J.; Muller, Ralph-Axel

    2010-01-01

    Objective: Autism spectrum disorder (ASD) is increasingly viewed as a disorder of functional networks, highlighting the importance of investigating white matter and interregional connectivity. We used diffusion tensor imaging (DTI) to examine white matter integrity for the whole brain and for corpus callosum, internal capsule, and middle…

  12. The diagnostic value of diffusion-weighted magnetic resonance imaging in soft tissue abscesses

    Energy Technology Data Exchange (ETDEWEB)

    Unal, Ozkan; Koparan, Halil Ibrahim [Yuezuencue Yil University, Department of Radiology, Van (Turkey); Avcu, Serhat, E-mail: serhatavcu@hotmail.com [Yuezuencue Yil University, Department of Radiology, Van (Turkey); Kalender, Ali Murat [Yuezuencue Yil University, Department of Orthopaedics, General Surgery, Van (Turkey); Kisli, Erol [Yuezuencue Yil University, Department of General Surgery, Van (Turkey)

    2011-03-15

    Purpose: To study the diagnostic value of diffusion-weighted imaging (DWI) in soft tissue abscesses. Materials and methods: Fifty patients were included in this study who were thought to have soft tissue abscess or cystic lesion as a result of clinical and radiological examinations. Localisations of the lesions were: 1 periorbital, 3 breast, 14 intraabdominal, and 32 intramuscular lesions. After other radiological examinations, DWI was performed. The signal intensity values of the lesions were evaluated qualitatively according to the hyperintensity on b-1000 DWI, using 1.5 T MR system. All of the lesions were aspirated after DWI, and detection of pus in the aspiration material was accepted as gold standard for the diagnosis of abscess. Results: In 38 of the 50 patients, hyperintensity was obtained on diffusion-weighted images. False-positive results were maintained in 2 of these patients, and true-positive results were maintained in 36 of them. In 11 of the 50 patients, hypointensity was visualised on diffusion-weighted images. False-negative results were maintained in 3 of these patients, and true-negative results were maintained in 8 of them. An abscess which was seen on post-contrast conventional MRI could not be seen on DWI, and this was regarded as false-negative. Conclusion: The sensitivity and specificity of diffusion-weighted images for detecting soft tissue abscesses were found to be 92% and 80%, respectively. DWI has a high diagnostic value in soft tissue abscesses, and is an important imaging modality that may be used for the differentiation of cysts and abscesses.

  13. The diagnostic value of diffusion-weighted magnetic resonance imaging in soft tissue abscesses

    International Nuclear Information System (INIS)

    Unal, Ozkan; Koparan, Halil Ibrahim; Avcu, Serhat; Kalender, Ali Murat; Kisli, Erol

    2011-01-01

    Purpose: To study the diagnostic value of diffusion-weighted imaging (DWI) in soft tissue abscesses. Materials and methods: Fifty patients were included in this study who were thought to have soft tissue abscess or cystic lesion as a result of clinical and radiological examinations. Localisations of the lesions were: 1 periorbital, 3 breast, 14 intraabdominal, and 32 intramuscular lesions. After other radiological examinations, DWI was performed. The signal intensity values of the lesions were evaluated qualitatively according to the hyperintensity on b-1000 DWI, using 1.5 T MR system. All of the lesions were aspirated after DWI, and detection of pus in the aspiration material was accepted as gold standard for the diagnosis of abscess. Results: In 38 of the 50 patients, hyperintensity was obtained on diffusion-weighted images. False-positive results were maintained in 2 of these patients, and true-positive results were maintained in 36 of them. In 11 of the 50 patients, hypointensity was visualised on diffusion-weighted images. False-negative results were maintained in 3 of these patients, and true-negative results were maintained in 8 of them. An abscess which was seen on post-contrast conventional MRI could not be seen on DWI, and this was regarded as false-negative. Conclusion: The sensitivity and specificity of diffusion-weighted images for detecting soft tissue abscesses were found to be 92% and 80%, respectively. DWI has a high diagnostic value in soft tissue abscesses, and is an important imaging modality that may be used for the differentiation of cysts and abscesses.

  14. White matter impairments in autism, evidence from voxel-based morphometry and diffusion tensor imaging.

    Science.gov (United States)

    Ke, Xiaoyan; Tang, Tianyu; Hong, Shanshan; Hang, Yueyue; Zou, Bing; Li, Huiguo; Zhou, Zhenyu; Ruan, Zongcai; Lu, Zuhong; Tao, Guotai; Liu, Yijun

    2009-04-10

    This study explored white matter abnormalities in a group of Chinese children with high functioning autism (HFA). Twelve male children with HFA and ten matched typically developing children underwent diffusion tensor imaging (DTI) as well three-dimensional T1-weighted MRI for voxel-based morphometry (VBM). We found a significant decrease of the white matter density in the right frontal lobe, left parietal lobe and right anterior cingulate and a significant increase in the right frontal lobe, left parietal lobe and left cingulate gyrus in the HFA group compared with the control group. The HFA group also had decreased FA in the frontal lobe and left temporal lobe. By combining DT-MRI FA and MRI volumetric analyses based on the VBM model, the results showed consistent white matter abnormalities in a group of Chinese children with HFA.

  15. Does white matter structure or hippocampal volume mediate associations between cortisol and cognitive ageing?

    Science.gov (United States)

    Cox, Simon R.; MacPherson, Sarah E.; Ferguson, Karen J.; Royle, Natalie A.; Maniega, Susana Muñoz; Hernández, Maria del C. Valdés; Bastin, Mark E.; MacLullich, Alasdair M.J.; Wardlaw, Joanna M.; Deary, Ian J.

    2015-01-01

    Elevated glucocorticoid (GC) levels putatively damage specific brain regions, which in turn may accelerate cognitive ageing. However, many studies are cross-sectional or have relatively short follow-up periods, making it difficult to relate GCs directly to changes in cognitive ability with increasing age. Moreover, studies combining endocrine, MRI and cognitive variables are scarce, measurement methods vary considerably, and formal tests of the underlying causal hypothesis (cortisol → brain → cognition) are absent. In this study, 90 men, aged 73 years, provided measures of fluid intelligence, processing speed and memory, diurnal and reactive salivary cortisol and two measures of white matter (WM) structure (WM hyperintensity volume from structural MRI and mean diffusivity averaged across 12 major tracts from diffusion tensor MRI), hippocampal volume, and also cognitive ability at age 11. We tested whether negative relationships between cognitive ageing differences (over more than 60 years) and salivary cortisol were significantly mediated by WM and hippocampal volume. Significant associations between reactive cortisol at 73 and cognitive ageing differences between 11 and 73 (r = −.28 to −.36, p cognition associations (cognitive ageing differences from childhood to the early 70s, partly via brain WM structure. PMID:26298692

  16. Shades of white : diffusion properties of T1- and FLAIR-defined white matter signal abnormalities differ in stages from cognitively normal to dementia

    NARCIS (Netherlands)

    Riphagen, Joost M.; Gronenschild, Ed HBM; Salat, David H.; Freeze, Whitney M.; Ivanov, Dimo; Clerx, Lies; Verhey, Frans R. J.; Aalten, Pauline; Jacobs, Heidi I. L.

    The underlying pathology of white matter signal abnormalities (WMSAs) is heterogeneous and may vary dependent on the magnetic resonance imaging contrast used to define them. We investigated differences in white matter diffusivity as an indicator for white matter integrity underlying WMSA based on

  17. Blue-Light Therapy following Mild Traumatic Brain Injury: Effects on White Matter Water Diffusion in the Brain

    Directory of Open Access Journals (Sweden)

    Sahil Bajaj

    2017-11-01

    Full Text Available Mild traumatic brain injury (mTBI is a common and often inconspicuous wound that is frequently associated with chronic low-grade symptoms and cognitive dysfunction. Previous evidence suggests that daily blue wavelength light therapy may be effective at reducing fatigue and improving sleep in patients recovering from mTBI. However, the effects of light therapy on recovering brain structure remain unexplored. In this study, we analyzed white matter diffusion properties, including generalized fractional anisotropy, and the quantity of water diffusion in isotropic (i.e., isotropic diffusion and anisotropic fashion (i.e., quantitative anisotropy, QA for fibers crossing 11 brain areas known to be significantly affected following mTBI. Specifically, we investigated how 6 weeks of daily morning blue light exposure therapy (compared to an amber-light placebo condition impacted changes in white matter diffusion in individuals with mTBI. We observed a significant impact of the blue light treatment (relative to the placebo on the amount of water diffusion (QA for multiple brain areas, including the corpus callosum, anterior corona radiata, and thalamus. Moreover, many of these changes were associated with improvements in sleep latency and delayed memory. These findings suggest that blue wavelength light exposure may serve as one of the potential non-pharmacological treatments for facilitating structural and functional recovery following mTBI; they also support the use of QA as a reliable neuro-biomarker for mTBI therapies.

  18. Permeability-diffusivity modeling vs. fractional anisotropy on white matter integrity assessment and application in schizophrenia.

    Science.gov (United States)

    Kochunov, P; Chiappelli, J; Hong, L E

    2013-01-01

    Diffusion tensor imaging (DTI) assumes a single pool of anisotropically diffusing water to calculate fractional anisotropy (FA) and is commonly used to ascertain white matter (WM) deficits in schizophrenia. At higher b-values, diffusion-signal decay becomes bi-exponential, suggesting the presence of two, unrestricted and restricted, water pools. Theoretical work suggests that semi-permeable cellular membrane rather than the presence of two physical compartments is the cause. The permeability-diffusivity (PD) parameters measured from bi-exponential modeling may offer advantages, over traditional DTI-FA, in identifying WM deficits in schizophrenia. Imaging was performed in N = 26/26 patients/controls (age = 20-61 years, average age = 40.5 ± 12.6). Imaging consisted of fifteen b-shells: b = 250-3800 s/mm(2) with 30 directions/shell, covering seven slices of mid-sagittal corpus callosum (CC) at 1.7 × 1.7 × 4.6 mm. 64-direction DTI was also collected. Permeability-diffusivity-index (PDI), the ratio of restricted to unrestricted apparent diffusion coefficients, and the fraction of unrestricted compartment (Mu) were calculated for CC and cingulate gray matter (GM). FA values for CC were calculated using tract-based-spatial-statistics. Patients had significantly reduced PDI in CC (p ≅ 10(- 4)) and cingulate GM (p = 0.002), while differences in CC FA were modest (p ≅ .03). There was no group-related difference in Mu. Additional theoretical-modeling analysis suggested that reduced PDI in patients may be caused by reduced cross-membrane water molecule exchanges. PDI measurements for cerebral WM and GM yielded more robust patient-control differences than DTI-FA. Theoretical work offers an explanation that patient-control PDI differences should implicate abnormal active membrane permeability. This would implicate abnormal activities in ion-channels that use water as substrate for ion exchange, in cerebral tissues of schizophrenia patients.

  19. Global and regional associations of smaller cerebral gray and white matter volumes with gait in older people.

    Directory of Open Access Journals (Sweden)

    Michele L Callisaya

    Full Text Available BACKGROUND: Gait impairments increase with advancing age and can lead to falls and loss of independence. Brain atrophy also occurs in older age and may contribute to gait decline. We aimed to investigate global and regional relationships of cerebral gray and white matter volumes with gait speed, and its determinants step length and cadence, in older people. METHODS: In a population-based study, participants aged >60 years without Parkinson's disease or brain infarcts underwent magnetic resonance imaging and gait measurements using a computerized walkway. Linear regression was used to study associations of total gray and white matter volumes with gait, adjusting for each other, age, sex, height and white matter hyperintensity volume. Other covariates considered in analyses included weight and vascular disease history. Voxel-based morphometry was used to study regional relationships of gray and white matter with gait. RESULTS: There were 305 participants, mean age 71.4 (6.9 years, 54% male, mean gait speed 1.16 (0.22 m/s. Smaller total gray matter volume was independently associated with poorer gait speed (p = 0.001 and step length (p<0.001, but not cadence. Smaller volumes of cortical and subcortical gray matter in bilateral regions important for motor control, vision, perception and memory were independently associated with slower gait speed and shorter steps. No global or regional associations were observed between white matter volume and gait independent of gray matter volume, white matter hyperintensity volume and other covariates. CONCLUSION: Smaller gray matter volume in bilaterally distributed brain networks serving motor control was associated with slower gait speed and step length, but not cadence.

  20. Identification of the Occipito-Pontine Tract Using Diffusion-Tensor Fiber Tracking in Adult-Onset Adrenoleukodystrophy with Topographic Disorientation

    Directory of Open Access Journals (Sweden)

    Yuji Uchida

    2011-05-01

    Full Text Available X-linked adrenoleukodystrophy is a severe and progressive neurodegenerative disease caused by the peroxisomal transporter ATP-binding cassette, subfamily D, member 1 gene mutations. The defect of this gene product results in accumulation of very-long-chain fatty acids in organs and serum, central demyelination, and peripheral axonopathy. Although there are different magnetic resonance (MR findings which reflect various phenotypes in adrenoleukodystrophy, some cases present with specific symmetrical occipital white-matter lesions. We describe a patient with adult-onset X-linked adrenoleukodystrophy with topographic disorientation, whose brain MR images revealed T2-signal hyperintensity along the occipito-pontine tract and lateral lemnisci, but not in the cortico-spinal tract in the brainstem. The occipito-pontine tract and lateral lemnisci were clearly detected using diffusion-tensor fiber tracking, suggesting that the topographic disorientation of this patient might be related to the occipito-pontine tract. MR tractography can effectively identify the occipito-pontine tract and may help to localize the fibers associated with clinical symptoms.

  1. New MRI technologies. Diffusion MRI and its application to functional neuroimaging and analyses of white matter integrity

    International Nuclear Information System (INIS)

    Kobayashi, Tetsuo

    2010-01-01

    Described is the technological aspect of MRI, MR diffusion-weighted imaging (MR-DWI), principles of its measurement and application for imaging the cerebral function and for aiding the quantitative diagnosis of brain diseases. The author explains the principle of MR imaging process; diffusion properties of water molecules, MR-DWI based on them and DW-fMRI of the brain; MR-diffusion tensor imaging (MR-DTI), its analysis and color acquisition, and tracking of white matter nerve fibers; analysis of white matter lesions by the tracking; and the new tracking method at the chiasm of nerve fascicles. The usual fMRI reflects the blood oxygen level depending (BOLD) signals whereas recently attracted DW-fMRI, the volume changes of nerve cells concomitant to nerve activation accompanying apparent changes of water diffusion coefficients in and out of cells which occur faster than BOLD signs, resulting in higher resolution of time and space. However, DWI requires the higher intensity of static magnetic field like 3T. MR-DTI acquires the anisotropic diffusion of water molecules using MR-DWI technique with application of 6 or more motion probing gradients, thus makes it possible to track the running directions of nerve fibers and capillary vessels, and is proposed to be a useful mean of specific fiber tracking in the white matter when displayed by 3 different colors exhibiting the directions like the right/left (x axis, red), anterior/posterior (y, green) and upper/lower (z, blue) sides of head. Recently, MR-DWI and MR-DTI have been found usable for pathogenic studies of brain diseases such as dementia. Tensor anisotropy is apparently lowered at the chiasm of nerve fascicles, the cause of tracking error, for which authors have developed a new method using the similarity of directional vector, not of tensor, before and behind the chiasm. As exemplified, MRI technology is further advancing even at present. (T.T.)

  2. Cerebral Microbleeds and White Matter Hyperintensities in Cognitively Healthy Elderly: A Cross-Sectional Cohort Study Evaluating the Effect of Arterial Stiffness

    Directory of Open Access Journals (Sweden)

    Anna-Märta Gustavsson

    2015-05-01

    Full Text Available Background: Arterial stiffness reflects the ageing processes in the vascular system, and studies have shown an association between reduced cognitive function and cerebral small vessel disease. Small vessel disease can be visualized as white matter hyperintensities (WMH and lacunar infarcts but also as cerebral microbleeds on brain magnetic resonance imaging (MRI. We aimed to investigate if arterial stiffness influences the presence of microbleeds, WMH and cognitive function in a population of cognitively healthy elderly. Methods: The study population is part of the Swedish BioFinder study and consisted of 208 individuals without any symptoms of cognitive impairment, who scored >27 points on the Mini-Mental State Examination. The participants (mean age, 72 years; 59% women underwent MRI of the brain with visual rating of microbleeds and WMH. Arterial stiffness was measured with carotid-femoral pulse wave velocity (cfPWV. Eight cognitive tests covering different cognitive domains were performed. Results: Microbleeds were detected in 12% and WMH in 31% of the participants. Mean (±standard deviation, SD cfPWV was 10.0 (±2.0 m/s. There was no association between the presence of microbleeds and arterial stiffness. There was a positive association between arterial stiffness and WMH independent of age or sex (odds ratio, 1.58; 95% confidence interval, 1.04-2.40, p 0.05. Cognitive performance was not associated with microbleeds, but individuals with WMH performed slightly worse than those without WMH on the Symbol Digit Modalities Test (mean ± SD, 35 ± 7.8 vs. 39 ± 8.1, p Conclusions: Arterial stiffness was not associated with the presence of cerebral microbleeds or cognitive function in cognitively healthy elderly. However, arterial stiffness was related to the presence of WMH, but the association was attenuated when multiple adjustments were made. There was a weak negative association between WMH and performance in one specific test of attention

  3. Age dependent white matter lesions and brain volume changes in healthy volunteers

    DEFF Research Database (Denmark)

    Christiansen, P; Larsson, H B; Thomsen, C

    1994-01-01

    The brain of 142 healthy volunteers aged 21 to 80 years were investigated using MR imaging. The number and size of the white matter hyperintensity lesions (WMHL) in the cerebral hemispheres were determined. Furthermore, the volume of the cerebral hemispheres and of the lateral ventricles was meas......The brain of 142 healthy volunteers aged 21 to 80 years were investigated using MR imaging. The number and size of the white matter hyperintensity lesions (WMHL) in the cerebral hemispheres were determined. Furthermore, the volume of the cerebral hemispheres and of the lateral ventricles...... was measured. An almost linear increase in the number of volunteers with WMHL was seen with aging for males and females. With aging a significant decrease in the volume of the cerebral hemispheres was found for males, and a significant increase in the volume of the lateral ventricles was seen for both males...... and females. Our results suggest that with aging central atrophy increases more (relatively) than cortical atrophy. No correlation was found between the decreasing volume of the cerebral hemispheres and the increasing number and size of WMHL, nor between the increasing volume of the lateral ventricles...

  4. Differences in integrity of white matter and changes with training in spelling impaired children: a diffusion tensor imaging study.

    Science.gov (United States)

    Gebauer, D; Fink, A; Filippini, N; Johansen-Berg, H; Reishofer, G; Koschutnig, K; Kargl, R; Purgstaller, C; Fazekas, F; Enzinger, C

    2012-07-01

    While the functional correlates of spelling impairment have been rarely investigated, to our knowledge no study exists regarding the structural characteristics of spelling impairment and potential changes with interventions. Using diffusion tensor imaging at 3.0 T, we here therefore sought to investigate (a) differences between children with poor spelling abilities (training group and waiting group) and controls, and (b) the effects of a morpheme-based spelling intervention in children with poor spelling abilities on DTI parameters. A baseline comparison of white matter indices revealed significant differences between controls and spelling-impaired children, mainly located in the right hemisphere (superior corona radiata (SCR), posterior limb of internal capsule, superior longitudinal fasciculus). After 5 weeks of training, spelling ability improved in the training group, along with increases in fractional anisotropy and decreases of radial diffusivity in the right hemisphere compared to controls. In addition, significantly higher decreases of mean diffusivity in the right SCR for the spelling-impaired training group compared to the waiting group were observed. Our results suggest that spelling impairment is associated with differences in white-matter integrity in the right hemisphere. We also provide first indications that white matter changes occur during successful training, but this needs to be more specifically addressed in future research.

  5. Tract-Specific Analyses of Diffusion Tensor Imaging Show Widespread White Matter Compromise in Autism Spectrum Disorder

    Science.gov (United States)

    Shukla, Dinesh K.; Keehn, Brandon; Muller, Ralph-Axel

    2011-01-01

    Background: Previous diffusion tensor imaging (DTI) studies have shown white matter compromise in children and adults with autism spectrum disorder (ASD), which may relate to reduced connectivity and impaired function of distributed networks. However, tract-specific evidence remains limited in ASD. We applied tract-based spatial statistics (TBSS)…

  6. Diffuse axonal injury: detection of changes in anisotropy of water diffusion by diffusion-weighted imaging

    International Nuclear Information System (INIS)

    Chan, J.H.M.; Tsui, E.Y.K.; Yuen, M.K.; Peh, W.C.G.; Fong, D.; Fok, K.F.; Leung, K.M.; Fung, K.K.L.

    2003-01-01

    Myelinated axons of white matter demonstrate prominent directional differences in water diffusion. We performed diffusion-weighted imaging on ten patients with head injury to explore the feasibility of using water diffusion anisotropy for quantitating diffuse axonal injury. We showed significant decrease in diffusion anisotropy indices in areas with or without signal abnormality on T2 and T2*-weighted images. We conclude that the water diffusion anisotropy index a potentially useful, sensitive and quantitative way of diagnosing and assessing patients with diffuse axonal injury. (orig.)

  7. White matter involvement in sporadic Creutzfeldt-Jakob disease.

    Science.gov (United States)

    Caverzasi, Eduardo; Mandelli, Maria Luisa; DeArmond, Stephen J; Hess, Christopher P; Vitali, Paolo; Papinutto, Nico; Oehler, Abby; Miller, Bruce L; Lobach, Irina V; Bastianello, Stefano; Geschwind, Michael D; Henry, Roland G

    2014-12-01

    Sporadic Creutzfeldt-Jakob disease is considered primarily a disease of grey matter, although the extent of white matter involvement has not been well described. We used diffusion tensor imaging to study the white matter in sporadic Creutzfeldt-Jakob disease compared to healthy control subjects and to correlated magnetic resonance imaging findings with histopathology. Twenty-six patients with sporadic Creutzfeldt-Jakob disease and nine age- and gender-matched healthy control subjects underwent volumetric T1-weighted and diffusion tensor imaging. Six patients had post-mortem brain analysis available for assessment of neuropathological findings associated with prion disease. Parcellation of the subcortical white matter was performed on 3D T1-weighted volumes using Freesurfer. Diffusion tensor imaging maps were calculated and transformed to the 3D-T1 space; the average value for each diffusion metric was calculated in the total white matter and in regional volumes of interest. Tract-based spatial statistics analysis was also performed to investigate the deeper white matter tracts. There was a significant reduction of mean (P=0.002), axial (P=0.0003) and radial (P=0.0134) diffusivities in the total white matter in sporadic Creutzfeldt-Jakob disease. Mean diffusivity was significantly lower in most white matter volumes of interest (PCreutzfeldt-Jakob disease. Mean diffusivity reduction reflected concomitant decrease of both axial and radial diffusivity, without appreciable changes in white matter anisotropy. Tract-based spatial statistics analysis showed significant reductions of mean diffusivity within the white matter of patients with sporadic Creutzfeldt-Jakob disease, mainly in the left hemisphere, with a strong trend (P=0.06) towards reduced mean diffusivity in most of the white matter bilaterally. In contrast, by visual assessment there was no white matter abnormality either on T2-weighted or diffusion-weighted images. Widespread reduction in white matter mean

  8. White matter biomarkers from diffusion MRI

    Science.gov (United States)

    Nørhøj Jespersen, Sune

    2018-06-01

    As part of an issue celebrating 2 decades of Joseph Ackerman editing the Journal of Magnetic Resonance, this paper reviews recent progress in one of the many areas in which Ackerman and his lab has made significant contributions: NMR measurement of diffusion in biological media, specifically in brain tissue. NMR diffusion signals display exquisite sensitivity to tissue microstructure, and have the potential to offer quantitative and specific information on the cellular scale orders of magnitude below nominal image resolution when combined with biophysical modeling. Here, I offer a personal perspective on some recent advances in diffusion imaging, from diffusion kurtosis imaging to microstructural modeling, and the connection between the two. A new result on the estimation accuracy of axial and radial kurtosis with axially symmetric DKI is presented. I moreover touch upon recently suggested generalized diffusion sequences, promising to offer independent microstructural information. We discuss the need and some methods for validation, and end with an outlook on some promising future directions.

  9. Diffuse-reflectance fourier-transform mid-infrared spectroscopy as a method of characterizing changes in soil organic matter

    Science.gov (United States)

    Diffuse-Reflectance Fourier-Transform Mid-Infrared Spectroscopy (MidIR) can identify the presence of important organic functional groups in soil organic matter (SOM). Soils contain myriad organic and inorganic components that absorb in the MidIR so spectral interpretation needs to be validated in or...

  10. Malnutrition and cerebral white matter lesions in dialysis patients

    International Nuclear Information System (INIS)

    Mukai, Masanori; Mukai, Kazumitsu; Ichikawa, Hiroo; Sanada, Daisuke; Shibata, Takanori; Kawamura, Mitsuru; Akizawa, Tadao; Wakasa, Mikio

    2008-01-01

    The objective of this study was to examine the association between nutritional status and the severity of cerebral white matter lesions (WMLs) in dialysis patients. Subjects consisted of 28 patients with end-stage renal failure who underwent regular hemodialysis in the affiliated hospitals of Showa University Hospital. All subjects underwent brain MRI and various clinical and laboratory tests. All subjects were divided into three groups based on the following criteria. Group I was defined as having 0 or 1 of the 4 findings of malnutrition (body mass index 2 , total lymphocyte counts 3 , serum albumin concentrations <3.5 g/dL, normalized protein catabolic rate <0.9 g/kg/day). Group II was defined as having 2 of these 4 findings, and group III was defined as having 3 or all of these 4 findings. WMLs detected on T2-weightd MRI were rated using the semiquantitative method yielding two continuous variables (perivascular hyperintensity (PVH) scores, deep subcortical white matter hyperintensity (DSWMH) scores). PVH and DSWMH scores were significantly higher in patients in groups III and II compared to that of those in group I. Multiple regression analysis demonstrated that the four findings of malnourishment described above had significant impact on PVH and DSWMH scores. These findings suggest that nutritional status (especially malnutrition) in dialysis patients may be involved in the severity of WMLs. (author)

  11. A comparison of substantia nigra T1 hyperintensity in Parkinson's disease dementia, Alzheimer's disease and age-matched controls: Volumetric analysis of neuromelanin imaging

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Won Jin; Park, Ju Yeon; Yun, Won Sung; Jeon, Ji Yeong; Moon, Yeon Sil; Kim, Hee Jin; Han, Seol Heui [Konkuk University School of Medicine, Seoul (Korea, Republic of); Kwak, Ki Chang; Lee, Jong Min [Dept. of Biomedical Engineering, Hanyang University, Seoul (Korea, Republic of)

    2016-09-15

    Neuromelanin loss of substantia nigra (SN) can be visualized as a T1 signal reduction on T1-weighted high-resolution imaging. We investigated whether volumetric analysis of T1 hyperintensity for SN could be used to differentiate between Parkinson's disease dementia (PDD), Alzheimer's disease (AD) and age-matched controls. This retrospective study enrolled 10 patients with PDD, 18 patients with AD, and 13 age-matched healthy elderly controls. MR imaging was performed at 3 tesla. To measure the T1 hyperintense area of SN, we obtained an axial thin section high-resolution T1-weighted fast spin echo sequence. The volumes of interest for the T1 hyperintense SN were drawn onto heavily T1-weighted FSE sequences through midbrain level, using the MIPAV software. The measurement differences were tested using the Kruskal-Wallis test followed by a post hoc comparison. A comparison of the three groups showed significant differences in terms of volume of T1 hyperintensity (p < 0.001, Bonferroni corrected). The volume of T1 hyperintensity was significantly lower in PDD than in AD and normal controls (p < 0.005, Bonferroni corrected). However, the volume of T1 hyperintensity was not different between AD and normal controls (p = 0.136, Bonferroni corrected). The volumetric measurement of the T1 hyperintensity of SN can be an imaging marker for evaluating neuromelanin loss in neurodegenerative diseases and a differential in PDD and AD cases.

  12. Continuous partial status cause of hyperintensity in cerebral cortex in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Lopez L, Ingeborg; Gonzalez L, Daniela; Quezada R, Patricio; Cartier R, Luis

    2012-01-01

    Magnetic Resonance Imaging has demonstrated functional changes of the cerebral cortex in relation to status epilepticus, which can eventually localize the origin of the crisis. The purpose of this presentation is relevant to this condition and pretends to highlight the action of incidental situations that can modify it. We present a 29 year old woman with a neurosurgical intervention for a neuroblastoma irradiated fifteen years ago, which incidentally starts a continuous partial status epilepticus, expressed by clonies of the face and left limbs associated with functional impotence, resistant to oral therapy. Faced with the suspicion of recurrence of the tumor, a brain MRI is performed, showing hyperintensity of all neural areas the right hemisphere, with no evidence of tumor recurrence. Once submitted the status epilepticus, the hyperintensity disappeared in the hemisphere. This extensive reaction of the neural structures might be related to a permanent effect of radiation, which may have caused a mismatch functional glia, of the blood-brain barrier and interneural network

  13. Neutrino diffusion in the pasta phase matter within the Thomas-Fermi approach

    Energy Technology Data Exchange (ETDEWEB)

    Furtado, U.J.; Avancini, S.S. [Universidade Federal de Santa Catarina, Departamento de Fisica, CFM, CP. 476, Florianopolis - SC (Brazil); University of Coimbra, CFisUC, Department of Physics, Coimbra (Portugal); Marinelli, J.R.; Martarello, W. [Universidade Federal de Santa Catarina, Departamento de Fisica, CFM, CP. 476, Florianopolis - SC (Brazil); Providencia, C. [University of Coimbra, CFisUC, Department of Physics, Coimbra (Portugal)

    2016-09-15

    The behaviour and properties of neutrinos in non-uniform nuclear matter, surrounded by electrons and other neutrinos are studied in the protoneutron star early stage characterized by trapped neutrinos. The nuclear matter itself is modelled by a relativistic mean-field approach, and models with both constant couplings and density-dependent couplings are considered. The so-called nuclear pasta phases at sub-saturation densities, described using the Thomas-Fermi approximation and solved in a Wigner-Seitz cell, are included in the calculation. We obtain the neutrino total cross section and mean free path, taking into account scattering and absorption processes and we compare the final results obtained with different parametrizations. The solution for this problem is important for the understanding of neutrino diffusion in a newly born neutron star after a supernovae explosion. It is shown that the pasta phase will increase the neutrino mean free path by as much as an order of magnitude, therefore contributing for shorter emission time-scales. (orig.)

  14. Neutrino diffusion in the pasta phase matter within the Thomas-Fermi approach

    International Nuclear Information System (INIS)

    Furtado, U.J.; Avancini, S.S.; Marinelli, J.R.; Martarello, W.; Providencia, C.

    2016-01-01

    The behaviour and properties of neutrinos in non-uniform nuclear matter, surrounded by electrons and other neutrinos are studied in the protoneutron star early stage characterized by trapped neutrinos. The nuclear matter itself is modelled by a relativistic mean-field approach, and models with both constant couplings and density-dependent couplings are considered. The so-called nuclear pasta phases at sub-saturation densities, described using the Thomas-Fermi approximation and solved in a Wigner-Seitz cell, are included in the calculation. We obtain the neutrino total cross section and mean free path, taking into account scattering and absorption processes and we compare the final results obtained with different parametrizations. The solution for this problem is important for the understanding of neutrino diffusion in a newly born neutron star after a supernovae explosion. It is shown that the pasta phase will increase the neutrino mean free path by as much as an order of magnitude, therefore contributing for shorter emission time-scales. (orig.)

  15. Magnetic resonance imaging and diffusion-weighted imaging of normal-appearing white matter in children and young adults with tuberous sclerosis complex

    International Nuclear Information System (INIS)

    Arulrajah, Sahayini; Ertan, Gulhan; Tekes, Aylin; Huisman, Thierry A.G.M.; Jordan, Lori; Khaykin, Elizabeth; Izbudak, Izlem

    2009-01-01

    Patients with tuberous sclerosis complex (TSC) frequently present with neurocognitive deficits which may be related to impaired white matter maturation. The purposes of our study were (a) to evaluate the white matter maturation in children and young adults with TSC by comparing the apparent diffusion coefficient (ADC) values of normal-appearing white matter (NAWM) with age-matched healthy controls and (b) to determine the association of NAWM-ADC values with the severity of neurological symptoms in TSC patients. Twenty-three TSC patients who underwent magnetic resonance imaging/diffusion-weighted imaging between January 2000 and January 2009 were studied. ADC values of NAWM were measured in the frontal, parietal, occipital lobes, and in the pons. ADC data were compared with age-matched normative data derived from healthy controls. Patients were neurologically scored by a pediatric neurologist. Two-sample t tests and linear regression were conducted using STATA software. ADC values of NAWM were higher in TSC patients compared with healthy controls; the increase, however, only reached statistical significance in the frontal white matter and pons in the age group between 96 and 144 months and in the right parietal and occipital white matter in the age group above 144 months. There was no significant change in neurological severity score per unit increase in ADC measurement. ADC values of NAWM appear increased in TSC patients. The abnormal ADC values suggest that myelination may be delayed/impaired in TSC patients, which could explain global neurocognitive deficits. Larger prospective studies, including diffusion tensor imaging, are necessary to validate our results. (orig.)

  16. Magnetic resonance imaging and diffusion-weighted imaging of normal-appearing white matter in children and young adults with tuberous sclerosis complex

    Energy Technology Data Exchange (ETDEWEB)

    Arulrajah, Sahayini; Ertan, Gulhan; Tekes, Aylin; Huisman, Thierry A.G.M. [Johns Hopkins Hospital, Division of Pediatric Radiology, Department of Radiology and Radiological Science, Baltimore, MD (United States); Jordan, Lori [Johns Hopkins School of Public Health, Division of Pediatric Neurology, Baltimore, MD (United States); Khaykin, Elizabeth [Johns Hopkins School of Public Health, Department of Mental Health, Baltimore, MD (United States); Izbudak, Izlem [Johns Hopkins Hospital, Division of Neuroradiology, Department of Radiology and Radiological Science, Baltimore, MD (United States)

    2009-11-15

    Patients with tuberous sclerosis complex (TSC) frequently present with neurocognitive deficits which may be related to impaired white matter maturation. The purposes of our study were (a) to evaluate the white matter maturation in children and young adults with TSC by comparing the apparent diffusion coefficient (ADC) values of normal-appearing white matter (NAWM) with age-matched healthy controls and (b) to determine the association of NAWM-ADC values with the severity of neurological symptoms in TSC patients. Twenty-three TSC patients who underwent magnetic resonance imaging/diffusion-weighted imaging between January 2000 and January 2009 were studied. ADC values of NAWM were measured in the frontal, parietal, occipital lobes, and in the pons. ADC data were compared with age-matched normative data derived from healthy controls. Patients were neurologically scored by a pediatric neurologist. Two-sample t tests and linear regression were conducted using STATA software. ADC values of NAWM were higher in TSC patients compared with healthy controls; the increase, however, only reached statistical significance in the frontal white matter and pons in the age group between 96 and 144 months and in the right parietal and occipital white matter in the age group above 144 months. There was no significant change in neurological severity score per unit increase in ADC measurement. ADC values of NAWM appear increased in TSC patients. The abnormal ADC values suggest that myelination may be delayed/impaired in TSC patients, which could explain global neurocognitive deficits. Larger prospective studies, including diffusion tensor imaging, are necessary to validate our results. (orig.)

  17. MRI findings of brain damage due to neonatal hypoglycemia

    International Nuclear Information System (INIS)

    Wang Lu; Fan Guoguang; Ji Xu; Sun Baohai; Guo Qiyong

    2009-01-01

    Objective: To report the MRI findings of brain damage observed in neonatal patients who suffered from isolated hypoglycemia and to explore the value of diffusion-weighted imaging(DWI) in early detection of neonatal hypoglycemic brain injury. Methods: Twelve neonates with isolated hypoglycemia (10 of the 12 were diagnosed to suffer from hypoglycemic encephalopathy) were enrolled in this study. They were first scanned at age from 3 days to 10 days with T 1 WI, T 2 WI and DWI(b is 0 s/mm 2 , 1000 s/mm 2 ), and 4 of them were then scanned from 7 days to 10 days following the initial scan. All acquired MR images were retrospectively analysed. Results: First series of DWI images showed distinct hyperintense signal in 11 cases in several areas including bilateral occipital cortex (2 cases), right occipital cortex (1 case), left occipital cortex and subcortical white matter(1 case), bilateral occipital cortex and subcortical white matter (2 cases), bilateral parieto-occipital cortex (2 cases), bilateral parieto-occipital cortex and subcortical white matter(2 cases), the splenium of corpus callosum (4 cases), bilateral corona radiata( 2 cases), left caudate nucleus and globus pallidus (1 case), bilateral thalamus (1 case), bilaterally posterior limb of internal capsule (1 case). In the initial T 1 WI and T 2 WI images, there were subtle hypointensity in the damaged cortical areas (3 cases), hyperintensity in the bilaterally affected occipital cortex( 1 case) on T 1 weighted images, and hyperintensity in the affected cortex and subcortical white matter with poor differentiation on T 2 weighted images. The followed-up MRI of 4 cases showed regional encephalomalacia in the affected occipital lobes(4 cases), slightly hyperintensity on T 2 weighted images in the damaged occipital cortex (2 cases), extensive demyelination (1 case), disappearance of hyperintensity of the splenium of corpus callosum (1 case), and persistent hyperintensity in the splenium of corpus callosum (1 case

  18. Pure methotrexate encephalopathy presenting with seizures: CT and MRI features

    Energy Technology Data Exchange (ETDEWEB)

    Loevblad, K.O.; Kelkar, P.; Ozdoba, C.; Remonda, L.; Schroth, G. [Department of Neuroradiology, Institute of Diagnostic Radiology, Inselspital, University of Bern, CH-3010 Bern (Switzerland); Ramelli, G. [Department of Pediatrics, Inselspital, University of Bern, Bern (Switzerland)

    1998-02-01

    With the advent of chemotherapy, mortality rates in acute lymphoblastic leukaemia (ALL) have decreased, but complications in the central nervous system have appeared. These include direct involvement of the brain itself and the development of chemotherapy-related encephalopathy as a delayed reaction. In most reported cases, this encephalopathy is believed to be due to necrotising angiitis arising from the combination of chemotherapy with adjuvant radiotherapy. We report the cases of four children with ALL who had been treated with high-dose intravenous and intrathecal chemotherapy but no radiation therapy, and who were admitted to hospital because of seizures. CT of the brain revealed the presence of diffuse periventricular white matter hypodensities in all cases and subcortical hyperdense foci in three cases. MRI showed diffuse hyperintense white matter lesions on T2-weighted images in all four patients; hypointense changes were observed on susceptibility-sensitive FLASH sequences in the hyperdense foci seen on CT as well as changes that were hyperintense on T1-weighted images. It was, therefore, concluded that the lesions corresponded to a leukoencephalopathy with calcific deposits. These findings are of a pure form of methotrexate encephalopathy causing seizures. (orig.) With 2 figs., 17 refs.

  19. Pure methotrexate encephalopathy presenting with seizures: CT and MRI features

    International Nuclear Information System (INIS)

    Loevblad, K.O.; Kelkar, P.; Ozdoba, C.; Remonda, L.; Schroth, G.; Ramelli, G.

    1998-01-01

    With the advent of chemotherapy, mortality rates in acute lymphoblastic leukaemia (ALL) have decreased, but complications in the central nervous system have appeared. These include direct involvement of the brain itself and the development of chemotherapy-related encephalopathy as a delayed reaction. In most reported cases, this encephalopathy is believed to be due to necrotising angiitis arising from the combination of chemotherapy with adjuvant radiotherapy. We report the cases of four children with ALL who had been treated with high-dose intravenous and intrathecal chemotherapy but no radiation therapy, and who were admitted to hospital because of seizures. CT of the brain revealed the presence of diffuse periventricular white matter hypodensities in all cases and subcortical hyperdense foci in three cases. MRI showed diffuse hyperintense white matter lesions on T2-weighted images in all four patients; hypointense changes were observed on susceptibility-sensitive FLASH sequences in the hyperdense foci seen on CT as well as changes that were hyperintense on T1-weighted images. It was, therefore, concluded that the lesions corresponded to a leukoencephalopathy with calcific deposits. These findings are of a pure form of methotrexate encephalopathy causing seizures. (orig.)

  20. About dark matter search and diffuse gamma ray emission with the H.E.S.S. experiment

    International Nuclear Information System (INIS)

    Charbonnier, A.

    2010-01-01

    Very high energy gamma-ray astronomy (E ≥ 30 GeV), that allows to probe non-thermal processes in the universe, is a rather young field of research. Up to now, most of the objects that have been observed are point-like or have small spatial extensions. However, the interaction of cosmic rays with the interstellar medium is expected to give rise to a diffuse emission at these energies. A preliminary study of the detectability of this diffuse component by the H.E.S.S. telescope array is presented. The latter has been operating since 2004 and detects the Cherenkov light from atmospheric showers that are generated by very high energy photons. The standard On-O background subtraction method is investigated along with the influence of the sky background noise on the recorded event rate. A second theme covered by this thesis is that of the detectability of dark matter by the H.E.S.S. experiment. This is performed using Clumpy, a semi-analytical code developed during this thesis. The Clumpy code calculates the gamma-ray flux from dark matter annihilation from user-defined galactic structure and sub-structure distributions. The H.E.S.S. ∼15 hour long observation of the Carina dwarf spheroidal galaxy has furthermore set an upper limit at 10 -22 cm 3 s -1 for the dark matter annihilation cross section. (author)

  1. [Total brain T2-hyperintense lesion-volume and the axonal damage in the normal-appearing white matter of brainstem in early lapsing-remitting multiple sclerosis].

    Science.gov (United States)

    Pascual-Lozano, A M; Martínez-Bisbal, M C; Boscá-Blasco, I; Valero-Merino, C; Coret-Ferrer, F; Martí-Bonmatí, L; Martínez-Granados, B; Celda, B; Casanova-Estruch, B

    To evaluate the relationship between the total brain T2-hyperintense lesion volume (TBT2LV) and the axonal damage in the normal-appearing white matter of brainstem measured by 1H-MRS in a group of early relapsing-remitting multiple sclerosis patients. 40 relapsing-remitting multiple sclerosis patients and ten sex- and age-matched healthy subjects were prospectively studied for two years. T2-weighted MR and 1H-MRS imaging were acquired at time of recruitment and at year two. The TBT2LV was calculated with a semiautomatic program; N-acetylaspartate (NAA), creatine (Cr) and choline (Cho) resonances areas were integrated with jMRUI program and the ratios were calculated for four volume elements that represented the brainstem. At basal study we obtained an axonal loss (as a decrement of NAA/ Cho ratio) in the group of patients compared with controls (p = 0.017); this axonal loss increased at the second year of the follow-up for patients (NAA/Cho decrease, p = 0.004, and NAA/Cr decrease, p = 0.002) meanwhile control subjects had no significant metabolic changes. Higher lesion load was correlated with a poor clinical outcome, being the correlation between the basal TBT2LV and the Expanded Disability Status Scale at second year (r = 0.299; p = 0.05). Besides, axonal loss was not homogeneous for all multiple sclerosis patients, being stronger in the subgroup of patients with high basal TBT2LV (p = 0.043; ANOVA). Our data suggest that axonal damage is early in multiple sclerosis and higher in patients high basal TBT2LV, suggesting a possible relationship between these two phenomena.

  2. White Matter Hyperintensity in Elderly Patients with Diabetes Mellitus Is Associated with Cognitive Impairment, Functional Disability, and a High Glycoalbumin/Glycohemoglobin Ratio

    Directory of Open Access Journals (Sweden)

    Yoshiaki Tamura

    2017-07-01

    Full Text Available Aims: Although evidence has accumulated that white matter hyperintensity (WMH is associated with the deterioration of cognitive function and impairment of activities of daily living (ADL, the clinical relevance of WMH in elderly patients with diabetes mellitus (DM is not still clear. The aim of this study was to examine whether WMH volume is associated with ADL and cognitive function and whether glucose control and glucose variability can affect WMH volume in these patients.Methods: This cross-sectional study investigated the associations of WMH with cognitive function and instrumental ADL (IADL, as well as metabolic and vascular risk factors in a total of 178 elderly patients with diabetes. The study assessed WMH volumes and the functional status of cognition and IADL. WMH volumes were evaluated by obtaining axial T2-weighted and fluid-attenuated inversion recovery sequence images on brain magnetic resonance imaging and assessing the images using Software for Neuro-Image Processing in Experimental Research.Results: We found a significant association between WMH volumes and Mini-Mental State Examination (MMSE scores (p = 0.039 and between WMH and IADL status (p = 0.006. Furthermore, we found significant relations of large WMH volumes with a high glycoalbumin/glycohemoglobin ratio (GA/HbA1c (p < 0.001. Large WMH volumes were also found to be associated with a low body mass index (p = 0.014 and a low diastolic blood pressure (p = 0.024, but not with HbA1c. Multiple regression analysis showed that high GA/HbA1c, which reflects high glucose variability, was a significant determining factor for large WMH volumes. We also found that GA/HbA1c was negatively associated with both MMSE (p = 0.036 and IADL (p < 0.001.Conclusion: GA/HbA1c, which is a marker of glucose variability, was independently associated with WMH volumes, which could lead to the decline of cognition and IADL in elderly patients with DM.

  3. Diffusive and quantum effects of water properties in different states of matter

    International Nuclear Information System (INIS)

    Yeh, Kuan-Yu; Huang, Shao-Nung; Chen, Li-Jen; Lin, Shiang-Tai

    2014-01-01

    The enthalpy, entropy, and free energy of water are important physical quantities for understanding many interesting phenomena in biological systems. However, conventional approaches require different treatments to incorporate quantum and diffusive effects of water in different states of matter. In this work, we demonstrate the use of the two-phase thermodynamic (2PT) model as a unified approach to obtain the properties of water over the whole phase region of water from short (∼20 ps) classical molecular dynamics trajectories. The 2PT model provides an effective way to separate the diffusive modes (gas-like component) from the harmonic vibrational modes (solid-like component) in the vibrational density of states (DoS). Therefore, both diffusive and quantum effect can be properly accounted for water by applying suitable statistical mechanical weighting functions to the DoS components. We applied the 2PT model to systematically examine the enthalpy, entropy, and their temperature dependence of five commonly used rigid water models. The 2PT results are found to be consistent with those obtained from more sophisticated calculations. While the thermodynamic properties determined from different water models are largely similar, the phase boundary determined from the equality of free energy is very sensitive to the small inaccuracy in the values of enthalpy and absolute entropy. The enthalpy, entropy, and diffusivity of water are strongly interrelated, which challenge further improvement of rigid water model via parameter fitting. Our results show that the 2PT is an efficient method for studying the properties of water under various chemical and biological environments

  4. MR imaging of diffuse bone marrow replacement in pediatric patients with solid malignancies

    International Nuclear Information System (INIS)

    Ruzal-Shapiro, C.; Berdon, W.E.; Cohen, M.D.; Abramson, S.J.

    1990-01-01

    This paper demonstrates that the MR imaging finding of dark T1/bright T2, associated with diffuse bone marrow tumor infiltration in leukemia, also occurs in solid tumors. The clinical course and results on plain radiographs, bone scans, and marrow aspiration were reviewed in two patients with solid tumors and two with leukemia whose MR studies showed a pattern of diffuse bone marrow T2 hypointensity and T2 hyperintensity. One case was followed serially through treatment. There were two cases of ALL, one neuroblastoma, and one rhabdomyosarcoma. Plain radiographs and bone scans showed metaphyseal changes with normal epiphyses and diaphyses. On MR images, flip-flop or reversal of the expected signal characteristics of fatty marrow was seen diffusely in the metaphyses, epiphyses, and diaphyses. All patients had positive bone marrow aspirates

  5. Multi-charge-state molecular dynamics and self-diffusion coefficient in the warm dense matter regime

    Science.gov (United States)

    Fu, Yongsheng; Hou, Yong; Kang, Dongdong; Gao, Cheng; Jin, Fengtao; Yuan, Jianmin

    2018-01-01

    We present a multi-ion molecular dynamics (MIMD) simulation and apply it to calculating the self-diffusion coefficients of ions with different charge-states in the warm dense matter (WDM) regime. First, the method is used for the self-consistent calculation of electron structures of different charge-state ions in the ion sphere, with the ion-sphere radii being determined by the plasma density and the ion charges. The ionic fraction is then obtained by solving the Saha equation, taking account of interactions among different charge-state ions in the system, and ion-ion pair potentials are computed using the modified Gordon-Kim method in the framework of temperature-dependent density functional theory on the basis of the electron structures. Finally, MIMD is used to calculate ionic self-diffusion coefficients from the velocity correlation function according to the Green-Kubo relation. A comparison with the results of the average-atom model shows that different statistical processes will influence the ionic diffusion coefficient in the WDM regime.

  6. Long-term prognosis of geriatric major depression in relation to cognition and white matter integrity: follow up of two cases

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo de Oliveira Alves

    2012-01-01

    Full Text Available INTRODUCTION: The geriatric depression (GD represents one of the most frequent psychiatric disorders in outpatient services specialized in old-age treatment. OBJECTIVE: The course of two illustrative cases of GD is discussed, highlighting its clinical picture after antidepressant treatment and underlining variables related to disease prognosis, treatment effectiveness and conversion to major cognitive disorders such as vascular dementia (VD. METHODS: The cognitive performance, depressive symptoms, autonomy and brain structural measurements as white matter hyperintensities (WMH and hippocampal size, and microstructural integrity of WM with diffusion tensor imaging were followed during four years. RESULTS: Case 1, with a severe degree of WMH, was associated with worsening cognition and increasing functional disability. Case 2, with mild WMH, an improvement of cognitive functioning could be seen. CONCLUSIONS: The existence of different subtypes of GD, as presented in this report, points a pathophysiological heterogeneity of GD, and suggests a possible continuum vascular depression (VaDp and vascular cognitive impairment (VCI.

  7. Age-related Differences in White Matter Integrity in Healthy Human Brain: Evidence from Structural Mri and Diffusion Tensor Imaging

    Directory of Open Access Journals (Sweden)

    Rishu Rathee

    2016-01-01

    Full Text Available The aim is to investigate the relationship between microstructural white matter (WM diffusivity indices and macrostructural WM volume (WMV among healthy individuals (20–85 years. Whole-brain diffusion measures were calculated from diffusion tensor imaging using FMRIB software library while WMV was estimated through voxel-based morphometry, and voxel-based analysis was carried out using tract-based spatial statistics. Our results revealed that mean diffusivity, axial diffusivity, and radial diffusivity had shown good correlation with WMV but not for fractional anisotropy (FA. Voxel-wise tract-based spatial statistics analysis for FA showed a significant decrease in four regions for middle-aged group compared to young-aged group, in 22 regions for old-aged group compared to middle-aged group, and in 26 regions for old-aged group compared to young-aged group ( P < 0.05. We found significantly lower WMV, FA, and mean diffusivity values in females than males and inverted-U trend for FA in males. We conclude differential age- and gender-related changes for structural WMV and WM diffusion indices.

  8. Preliminary study of normal changes in brain white matter during childhood with diffusion tensor imaging

    International Nuclear Information System (INIS)

    Xiao Jiangxi; Guo Xuemei; Xie Sheng; Wang Xiaoying; Jiang Xuexiang

    2005-01-01

    Objective: To study the normal changes in brain white matter during childhood by analyzing the anisotropy of different regions and different age groups with diffusion tensor imaging (DTI). Methods: DTI was performed in 89 children (age range from 2 days to 18 years) without brain abnormalities, and the data measured in fractional anisotropy (FA) maps were analyzed statistically. Children less than 6 months were ranged to group 1, 6-12 months to group 2, 1-3 years to group 3, 3-5 years to group 4, 5-8 years to group 5, 8-12 years to group 6, 12-18 years to group 7. Results: (1) There were significant differences in anisotropy (FA values) among different regions of white matter in brain. In group 7, the FA value of corpus callosum was 0.826 ± 0.039, middle cerebellar peduncle 0.678 ± 0.043, frontal white matter 0.489 ± 0.033. (2) The anisotropy among different age group was statistically different, P<0.05. (3) The anisotropy of white matter increased with the increasing of age, and FA values showed positively exponentially correlations with age. Conclusion: DTI shows the structure of white matters in vivo, with which normal changes in brain during childhood can be evaluated. (authors)

  9. Diffusion abnormalities of the globi pallidi in manganese neurotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    McKinney, Alexander M.; Filice, Ross W.; Teksam, Mehmet; Casey, Sean; Truwit, Charles; Clark, H. Brent; Woon, Carolyn; Liu, Hai Ying [Department of Radiology, Medical School, Box 292, 420 Delaware Street S.E., 55455, Minneapolis, MN (United States)

    2004-04-01

    Manganese is an essential trace metal required for normal central nervous system function, which is toxic when in excess amounts in serum. Manganese neurotoxicity has been demonstrated in patients with chronic liver/biliary failure where an inability to excrete manganese via the biliary system causes increased serum levels, and in patients on total parenteral nutrition (TPN), occupational/inhalational exposure, or other source of excess exogenous manganese. Manganese has been well described in the literature to deposit selectively in the globi pallidi and to induce focal neurotoxicity. We present a case of a 53-year-old woman who presented for a brain MR 3 weeks after liver transplant due to progressively decreasing level of consciousness. The patient had severe liver failure by liver function tests and bilirubin levels, and had also been receiving TPN since the transplant. The MR demonstrated symmetric hyperintensity on T1-weighted images in the globi pallidi. Apparent diffusion coefficient (ADC) map indicated restricted diffusion in the globi pallidi bilaterally. The patient eventually succumbed to systemic aspergillosis 3 days after the MR. The serum manganese level was 195 mcg/l (micrograms per liter) on postmortem exam (over 20 times the upper limits of normal). The patient was presumed to have suffered from manganese neurotoxicity since elevated serum manganese levels have been shown in the literature to correlate with hyperintensity on T1-weighted images, neurotoxicity symptoms, and focal concentration of manganese in the globi pallidi. Neuropathologic sectioning of the globi pallidi at autopsy was also consistent with manganese neurotoxicity. (orig.)

  10. Cardiorespiratory fitness, cognition and brain structure after TIA or minor ischemic stroke.

    Science.gov (United States)

    Boss, H Myrthe; Van Schaik, Sander M; Witkamp, Theo D; Geerlings, Mirjam I; Weinstein, Henry C; Van den Berg-Vos, Renske M

    2017-10-01

    Background It is not known whether cardiorespiratory fitness is associated with better cognitive performance and brain structure in patients with a TIA or minor ischemic stroke. Aims To examine the association between cardiorespiratory fitness, cognition and brain structure in patients with a TIA and minor stroke. Methods The study population consisted of patients with a TIA or minor stroke with a baseline measurement of the peak oxygen consumption, a MRI scan of brain and neuropsychological assessment. Composite z-scores were calculated for the cognitive domains attention, memory and executive functioning. White matter hyperintensities, microbleeds and lacunes were rated visually. The mean apparent diffusion coefficient was measured in regions of interest in frontal and occipital white matter and in the centrum semiovale as a marker of white matter structure. Normalized brain volumes were estimated by use of Statistical Parametric Mapping. Results In 84 included patients, linear regression analysis adjusted for age, sex and education showed that a higher peak oxygen consumption was associated with higher cognitive z-scores, a larger grey matter volume (B = 0.15 (95% CI 0.05; 0.26)) and a lower mean apparent diffusion coefficient (B = -.004 (95% CI -.007; -.001)). We found no association between the peak oxygen consumption and severe white matter hyperintensities, microbleeds, lacunes and total brain volume. Conclusions These data suggest that cardiorespiratory fitness is associated with better cognitive performance, greater grey matter volume and greater integrity of the white matter in patients with a TIA or minor ischemic stroke. Further prospective trials are necessary to define the effect of cardiorespiratory fitness on cognition and brain structure in patients with TIA or minor stroke.

  11. Preoperative diffusion-weighted imaging of single brain metastases correlates with patient survival times.

    Directory of Open Access Journals (Sweden)

    Anna Sophie Berghoff

    Full Text Available BACKGROUND: MRI-based diffusion-weighted imaging (DWI visualizes the local differences in water diffusion in vivo. The prognostic value of DWI signal intensities on the source images and apparent diffusion coefficient (ADC maps respectively has not yet been studied in brain metastases (BM. METHODS: We included into this retrospective analysis all patients operated for single BM at our institution between 2002 and 2010, in whom presurgical DWI and BM tissue samples were available. We recorded relevant clinical data, assessed DWI signal intensity and apparent diffusion coefficient (ADC values and performed histopathological analysis of BM tissues. Statistical analyses including uni- and multivariate survival analyses were performed. RESULTS: 65 patients (34 female, 31 male with a median overall survival time (OS of 15 months (range 0-99 months were available for this study. 19 (29.2% patients presented with hyper-, 3 (4.6% with iso-, and 43 (66.2% with hypointense DWI. ADCmean values could be determined in 32 (49.2% patients, ranged from 456.4 to 1691.8*10⁻⁶ mm²/s (median 969.5 and showed a highly significant correlation with DWI signal intensity. DWI hyperintensity correlated significantly with high amount of interstitial reticulin deposition. In univariate analysis, patients with hyperintense DWI (5 months and low ADCmean values (7 months had significantly worse OS than patients with iso/hypointense DWI (16 months and high ADCmean values (30 months, respectively. In multivariate survival analysis, high ADCmean values retained independent statistical significance. CONCLUSIONS: Preoperative DWI findings strongly and independently correlate with OS in patients operated for single BM and are related to interstitial fibrosis. Inclusion of DWI parameters into established risk stratification scores for BM patients should be considered.

  12. White matter microstructure and cognitive decline in metabolic syndrome: a review of diffusion tensor imaging.

    Science.gov (United States)

    Alfaro, Freddy J; Gavrieli, Anna; Saade-Lemus, Patricia; Lioutas, Vasileios-Arsenios; Upadhyay, Jagriti; Novak, Vera

    2018-01-01

    Metabolic syndrome is a cluster of cardiovascular risk factors defined by the presence of abdominal obesity, glucose intolerance, hypertension and/or dyslipidemia. It is a major public health epidemic worldwide, and a known risk factor for the development of cognitive dysfunction and dementia. Several studies have demonstrated a positive association between the presence of metabolic syndrome and worse cognitive outcomes, however, evidence of brain structure pathology is limited. Diffusion tensor imaging has offered new opportunities to detect microstructural white matter changes in metabolic syndrome, and a possibility to detect associations between functional and structural abnormalities. This review analyzes the impact of metabolic syndrome on white matter microstructural integrity, brain structure abnormalities and their relationship to cognitive function. Each of the metabolic syndrome components exerts a specific signature of white matter microstructural abnormalities. Metabolic syndrome and its components exert both additive/synergistic, as well as, independent effects on brain microstructure thus accelerating brain aging and cognitive decline. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Analysis of normal-appearing white matter of multiple sclerosis by tensor-based two-compartment model of water diffusion

    International Nuclear Information System (INIS)

    Tachibana, Yasuhiko; Obata, Takayuki; Yoshida, Mariko; Hori, Masaaki; Kamagata, Koji; Suzuki, Michimasa; Fukunaga, Issei; Kamiya, Kouhei; Aoki, Shigeki; Yokoyama, Kazumasa; Hattori, Nobutaka; Inoue, Tomio

    2015-01-01

    To compare the significance of the two-compartment model, considering diffusional anisotropy with conventional diffusion analyzing methods regarding the detection of occult changes in normal-appearing white matter (NAWM) of multiple sclerosis (MS). Diffusion-weighted images (nine b-values with six directions) were acquired from 12 healthy female volunteers (22-52 years old, median 33 years) and 13 female MS patients (24-48 years old, median 37 years). Diffusion parameters based on the two-compartment model of water diffusion considering diffusional anisotropy was calculated by a proposed method. Other parameters including diffusion tensor imaging and conventional apparent diffusion coefficient (ADC) were also obtained. They were compared statistically between the control and MS groups. Diffusion of the slow diffusion compartment in the radial direction of neuron fibers was elevated in MS patients (0.121 x 10 -3 mm 2 /s) in comparison to control (0.100 x 10 -3 mm 2 /s), the difference being significant (P = 0.001). The difference between the groups was not significant in other comparisons, including conventional ADC and fractional anisotropy (FA) of diffusion tensor imaging. The proposed method was applicable to clinically acceptable small data. The parameters obtained by this method improved the detectability of occult changes in NAWM compared to the conventional methods. (orig.)

  14. Analysis of normal-appearing white matter of multiple sclerosis by tensor-based two-compartment model of water diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Tachibana, Yasuhiko [National Institute of Radiological Sciences, Research Center for Charged Particle Therapy, Chiba (Japan); Yokohama City University Graduate School of Medicine, Department of Radiology, Yokohama (Japan); Juntendo University School of Medicine, Department of Radiology, Tokyo (Japan); Obata, Takayuki [National Institute of Radiological Sciences, Research Center for Charged Particle Therapy, Chiba (Japan); Yoshida, Mariko; Hori, Masaaki; Kamagata, Koji; Suzuki, Michimasa; Fukunaga, Issei; Kamiya, Kouhei; Aoki, Shigeki [Juntendo University School of Medicine, Department of Radiology, Tokyo (Japan); Yokoyama, Kazumasa; Hattori, Nobutaka [Juntendo University School of Medicine, Department of Neurology, Tokyo (Japan); Inoue, Tomio [Yokohama City University Graduate School of Medicine, Department of Radiology, Yokohama (Japan)

    2015-06-01

    To compare the significance of the two-compartment model, considering diffusional anisotropy with conventional diffusion analyzing methods regarding the detection of occult changes in normal-appearing white matter (NAWM) of multiple sclerosis (MS). Diffusion-weighted images (nine b-values with six directions) were acquired from 12 healthy female volunteers (22-52 years old, median 33 years) and 13 female MS patients (24-48 years old, median 37 years). Diffusion parameters based on the two-compartment model of water diffusion considering diffusional anisotropy was calculated by a proposed method. Other parameters including diffusion tensor imaging and conventional apparent diffusion coefficient (ADC) were also obtained. They were compared statistically between the control and MS groups. Diffusion of the slow diffusion compartment in the radial direction of neuron fibers was elevated in MS patients (0.121 x 10{sup -3} mm{sup 2}/s) in comparison to control (0.100 x 10{sup -3} mm{sup 2}/s), the difference being significant (P = 0.001). The difference between the groups was not significant in other comparisons, including conventional ADC and fractional anisotropy (FA) of diffusion tensor imaging. The proposed method was applicable to clinically acceptable small data. The parameters obtained by this method improved the detectability of occult changes in NAWM compared to the conventional methods. (orig.)

  15. Characterizing the microstructural basis of “unidentified bright objects” in neurofibromatosis type 1 : A combined in vivo multicomponent T2 relaxation and multi-shell diffusion MRI analysis

    NARCIS (Netherlands)

    Billiet, T.; Mädler, B.; D'Arco, F.; Deprez, S.; Plasschaert, E.; Leemans, A.; Zhang, H.; Van Den Bergh, B.R.H.; Vandenbulcke, M.; Legius, E.; Sunaert, S.; Emsell, L.

    2014-01-01

    Introduction The histopathological basis of “unidentified bright objects” (UBOs) (hyperintense regions seen on T2-weighted magnetic resonance (MR) brain scans in neurofibromatosis-1 (NF1)) remains unclear. New in vivo MRI-based techniques (multi-exponential T2 relaxation (MET2) and diffusion MR

  16. Clinicoradiological changes of brain NK/T cell lymphoma manifesting pure akinesia: a case report

    Directory of Open Access Journals (Sweden)

    Shimokawa Reiko

    2011-11-01

    Full Text Available Abstract Background Pure akinesia (PA is a distinct form of parkinsonism characterized by freezing phenomena. Little is known about brain tumor-associated PA. We highlight the clinicoradiological changes in a patient with PA and central nervous system (CNS metastases of natural killer/T-cell lymphoma (NKTL. Case presentation A 68-year-old man with stage IVB extranodal NKTL developed a gait disturbance. Neurological examination of his gait revealed freezing, start hesitation, short step, forward flexion posture, festination and postural instability. Mild facial hypomimia and micrographia were observed. There was no rigidity or tremor in any of the four extremities. Brain magnetic resonance imaging (MRI displayed T2-hyperintense lesions in the dorsal brainstem, cerebellum and periventricular white matter. Diffusion-weighted imaging (DWI and the apparent diffusion coefficient (ADC revealed hyperintensity in these regions. Cerebrospinal fluid cytology revealed CD56-positive cells on immunohistochemical staining. The patient's neurological deficits did not respond to L-dopa treatment and intrathecal administration of methotrexate (MTX. Two weeks later, he displayed confusion and generalized convulsions. T2-hyperintense lesions spread to the basal ganglia and the infratentorial regions. Gadolinium enhancement was observed in the cerebellum and frontal subcortex. DWI and the ADC revealed diffusion-restricted lesions in the middle cerebellar peduncles, left internal capsules and cerebral white matter. MTX pulse therapy and intrathecal administration of cytosine arabinoside and MTX were performed. Two months later, his ambulatory state was normalized. Brain MRI also revealed marked alleviation of the infratentorial and supratentorial lesions. Conclusions The clinicoradiological profile of our patient suggested that dorsal ponto-mesencephalic lesions could contribute to the pathogenesis of PA. Physicians should pay more attention to striking CNS seeding

  17. Voxel-based analyses of gray/white matter volume and diffusion tensor data in major depression. Presidential award proceedings

    International Nuclear Information System (INIS)

    Abe, Osamu; Yamasue, Hidenori; Kasai, Kiyoto

    2008-01-01

    Previous neuroimaging studies have revealed that frontolimbic dysfunction may contribute to the pathophysiology of major depressive disorder. We used voxel-based analysis to simultaneously elucidate regional changes in gray/white matter volume, mean diffusivity (MD), and fractional anisotropy (FA) in the central nervous system of patients with unipolar major depression. We studied 21 right-handed patients and 42 age- and gender-matched right-handed normal subjects without central nervous system disorders. All image processing and statistical analyses were performed using SPM5 software. Local areas showing significant gray matter volume reduction in depressive patients compared with normal controls were observed in the right parahippocampal gyrus, hippocampus, bilateral middle frontal gyri, bilateral anterior cingulate cortices, left parietal and occipital lobes, and right superior temporal gyrus. Local areas showing increased mean diffusivity in depressive patients were observed in the bilateral parahippocampal gyri, hippocampus, pons, cerebellum, left frontal and temporal lobes, and right frontal lobe. There was no significant difference between the 2 groups for fractional anisotropy and white matter volume in the entire brain. Although there was no local area in which FA and MD were significantly correlated with disease severity, FA tended to correlate negatively with depression days (total accumulated days in depressive state) in the right anterior cingulate and the left frontal white matter (FDR-corrected P=0.055 for both areas). These results suggest that the frontolimbic neural circuit may play an important role in the neuropathology of patients with major depression. (author)

  18. White matter abnormalities in major depressive disorder with melancholic and atypical features: A diffusion tensor imaging study.

    Science.gov (United States)

    Ota, Miho; Noda, Takamasa; Sato, Noriko; Hattori, Kotaro; Hori, Hiroaki; Sasayama, Daimei; Teraishi, Toshiya; Nagashima, Anna; Obu, Satoko; Higuchi, Teruhiko; Kunugi, Hiroshi

    2015-06-01

    The DSM-IV recognizes some subtypes of major depressive disorder (MDD). It is known that the effectiveness of antidepressants differs among the MDD subtypes, and thus the differentiation of the subtypes is important. However, little is known as to structural brain changes in MDD with atypical features (aMDD) in comparison with MDD with melancholic features (mMDD), which prompted us to examine possible differences in white matter integrity assessed with diffusion tensor imaging (DTI) between these two subtypes. Subjects were 21 patients with mMDD, 24 with aMDD, and 37 age- and sex-matched healthy volunteers whose DTI data were obtained by 1.5 tesla magnetic resonance imaging. We compared fractional anisotropy and mean diffusivity value derived from DTI data on a voxel-by-voxel basis among the two diagnostic groups and healthy subjects. There were significant decreases of fractional anisotropy and increases of mean diffusivity in patients with MDD compared with healthy subjects in the corpus callosum, inferior fronto-occipital fasciculus, and left superior longitudinal fasciculus. However, we detected no significant difference in any brain region between mMDD and aMDD. Our results suggest that patients with MDD had reduced white matter integrity in some regions; however, there was no major difference between aMDD and mMDD. © 2014 The Authors. Psychiatry and Clinical Neurosciences © 2014 Japanese Society of Psychiatry and Neurology.

  19. Quantification of diffusion tensor imaging in normal white matter maturation of early childhood using an automated processing pipeline

    International Nuclear Information System (INIS)

    Loh, K.B.; Ramli, N.; Tan, L.K.; Roziah, M.; Rahmat, K.; Ariffin, H.

    2012-01-01

    The degree and status of white matter myelination can be sensitively monitored using diffusion tensor imaging (DTI). This study looks at the measurement of fractional anistropy (FA) and mean diffusivity (MD) using an automated ROI with an existing DTI atlas. Anatomical MRI and structural DTI were performed cross-sectionally on 26 normal children (newborn to 48 months old), using 1.5-T MRI. The automated processing pipeline was implemented to convert diffusion-weighted images into the NIfTI format. DTI-TK software was used to register the processed images to the ICBM DTI-81 atlas, while AFNI software was used for automated atlas-based volumes of interest (VOIs) and statistical value extraction. DTI exhibited consistent grey-white matter contrast. Triphasic temporal variation of the FA and MD values was noted, with FA increasing and MD decreasing rapidly early in the first 12 months. The second phase lasted 12-24 months during which the rate of FA and MD changes was reduced. After 24 months, the FA and MD values plateaued. DTI is a superior technique to conventional MR imaging in depicting WM maturation. The use of the automated processing pipeline provides a reliable environment for quantitative analysis of high-throughput DTI data. (orig.)

  20. Quantification of diffusion tensor imaging in normal white matter maturation of early childhood using an automated processing pipeline

    Energy Technology Data Exchange (ETDEWEB)

    Loh, K.B.; Ramli, N.; Tan, L.K.; Roziah, M. [University of Malaya, Department of Biomedical Imaging, University Malaya Research Imaging Centre (UMRIC), Faculty of Medicine, Kuala Lumpur (Malaysia); Rahmat, K. [University of Malaya, Department of Biomedical Imaging, University Malaya Research Imaging Centre (UMRIC), Faculty of Medicine, Kuala Lumpur (Malaysia); University Malaya, Biomedical Imaging Department, Kuala Lumpur (Malaysia); Ariffin, H. [University of Malaya, Department of Paediatrics, Faculty of Medicine, Kuala Lumpur (Malaysia)

    2012-07-15

    The degree and status of white matter myelination can be sensitively monitored using diffusion tensor imaging (DTI). This study looks at the measurement of fractional anistropy (FA) and mean diffusivity (MD) using an automated ROI with an existing DTI atlas. Anatomical MRI and structural DTI were performed cross-sectionally on 26 normal children (newborn to 48 months old), using 1.5-T MRI. The automated processing pipeline was implemented to convert diffusion-weighted images into the NIfTI format. DTI-TK software was used to register the processed images to the ICBM DTI-81 atlas, while AFNI software was used for automated atlas-based volumes of interest (VOIs) and statistical value extraction. DTI exhibited consistent grey-white matter contrast. Triphasic temporal variation of the FA and MD values was noted, with FA increasing and MD decreasing rapidly early in the first 12 months. The second phase lasted 12-24 months during which the rate of FA and MD changes was reduced. After 24 months, the FA and MD values plateaued. DTI is a superior technique to conventional MR imaging in depicting WM maturation. The use of the automated processing pipeline provides a reliable environment for quantitative analysis of high-throughput DTI data. (orig.)

  1. Pattern of mri brain abnormalities in rheumatic patients with neurological involvement: a tertiary care teaching hospital experience

    International Nuclear Information System (INIS)

    Parvez, K.; Arfaj, A.; Naseeb, F.; Daif, A.K.

    2015-01-01

    Objective: To explore the pattern of abnormalities seen on MRI in rheumatic patients with neurological manifestations and to interpret the findings in relation to clinical picture. Study Design: Descriptive study. Place and Duration of Study: Rheumatology unit, King Khalid University Hospital, Riyadh, Saudi Arabia from January 2013 to February 2014. Patients and Methods: We prospectively included rheumatic patients with neurological symptoms and signs. The clinical data were correlated with MRI findings by a team comprising of a rheumatologist, neurologist and neuro-radiologist. Data was analyzed using simple statistical analysis. Results: Fifty patients were recruited with a mean age of 36.4 ± 10.76 years (range 17-62). Among SLE patients with seizures, focal deficit and headache white matter hyperintensities were found in 9 (64.28%), 4 (50%), 4 (80%) patients respectively. Out of seven SLE patients with global dysfunction, 3 (42.85%) had brain atrophy and 2 (28.57%) normal MRI. In Behcet disease with focal deficit, 3 (75%) patients had white matter hyperintensities and 1 (25%) had brainstem involvement. In Behcet disease with headache, 2 (50%) had normal MRI, 1 (25%) brainstem hyper-intensities and 1 (25%) had subacute infarct. Two (66%) of three Primary APS patients had white matter hyperintensities while third (33%) had old infarct. Both patients of polyarteritisnodosa, had white matter hyperintensities. Out of two Wegener granulomatosis one had white matter hyperintensities and other had ischemic changes in optic nerves. The only one scleroderma patient had white matter hyperintensities. Conclusion: We found that white matter hyperintensities was the most common MRI abnormality in our study group which in most of the cases had poor clinical correlation. No distinct pattern of CNS involvement on MRI was observed in various rheumatic disorders. (author)

  2. Connectivity-enhanced diffusion analysis reveals white matter density disruptions in first episode and chronic schizophrenia

    Directory of Open Access Journals (Sweden)

    Rachael G. Grazioplene

    microstructural group differences. These results underline the need to move beyond tensor-based models in favor of acquisition and analysis techniques that can help disambiguate different sources of white matter disruptions associated with schizophrenia. Keywords: Schizophrenia, Diffusion imaging, DWI, DTI, First episode, Chronic, White matter, Fiber density, Fiber organization

  3. Comparison of Multi-Tensor Diffusion Models' Performance for White Matter Integrity Estimation in Chronic Stroke

    Directory of Open Access Journals (Sweden)

    Olena G. Filatova

    2018-04-01

    Full Text Available Better insight into white matter (WM alterations after stroke onset could help to understand the underlying recovery mechanisms and improve future interventions. MR diffusion imaging enables to assess such changes. Our goal was to investigate the relation of WM diffusion characteristics derived from diffusion models of increasing complexity with the motor function of the upper limb. Moreover, we aimed to evaluate the variation of such characteristics across different WM structures of chronic stroke patients in comparison to healthy subjects. Subjects were scanned with a two b-value diffusion-weighted MRI protocol to exploit multiple diffusion models: single tensor, single tensor with isotropic compartment, bi-tensor model, bi-tensor with isotropic compartment. From each model we derived the mean tract fractional anisotropy (FA, mean (MD, radial (RD and axial (AD diffusivities outside the lesion site based on a WM tracts atlas. Asymmetry of these measures was correlated with the Fugl-Meyer upper extremity assessment (FMA score and compared between patient and control groups. Eighteen chronic stroke patients and eight age-matched healthy individuals participated in the study. Significant correlation of the outcome measures with the clinical scores of stroke recovery was found. The lowest correlation of the corticospinal tract FAasymmetry and FMA was with the single tensor model (r = −0.3, p = 0.2 whereas the other models reported results in the range of r = −0.79 ÷ −0.81 and p = 4E-5 ÷ 8E-5. The corticospinal tract and superior longitudinal fasciculus showed most alterations in our patient group relative to controls. Multiple compartment models yielded superior correlation of the diffusion measures and FMA compared to the single tensor model.

  4. Diffusion weighted MR imaging in non-infarct lesions of the brain

    Energy Technology Data Exchange (ETDEWEB)

    Karaarslan, E. [Department of Radiology, American Hospital, Sisli, Istanbul (Turkey)], E-mail: ercankaraarslan@yahoo.com; Arslan, A. [Department of Radiology, Kocaeli University Medical School, Kocaeli (Turkey)], E-mail: arzuarslan@netscape.net

    2008-03-15

    Diffusion weighted imaging (DWI) is a relatively new method in which the images are formed by the contrast produced by the random microscopic motion of water molecules in different tissues. Although DWI has been tried for different organ systems, it has been found its primary use in the central nervous system. The most widely used clinical application is in the detection of hyperacute infarcts and the differentiation of acute or subacute infarction from chronic infarction. Recently DWI has been applied to various other cerebral diseases. In this pictorial paper the authors demonstrated different DWI patterns of non-infarct lesions of the brain which are hyperintense in the diffusion trace image, such as infectious, neoplastic and demyelinating diseases, encephalopathies - including hypoxic-ischemic, hypertensive, eclamptic, toxic, metabolic and mitochondrial encephalopathies - leukodystrophies, vasculitis and vasculopathies, hemorrhage and trauma.

  5. Diffusion-weighted MR imaging for liver cancer follow-up after transcatheter arterial chemoembolization

    International Nuclear Information System (INIS)

    Yuan Zheng; Xiao Xiangsheng; Liu Shiyuan; Dong Sheng; Dong Weihua; Jia Ningyang; Sun Zhichao; Ye Xiaodan; Yan Bing

    2007-01-01

    Objective: To investigate prospectively the apparent diffusion coefficient (ADC)in evaluating the capability of diffusion-weighted imaging (DWI) technique for detecting viable tumor tissue after transarterial chemoembolization (TACE) of liver cancer. Methods: Institutional review board approval was obtained, and all patients were provided with informed consent. DWI, enhanced CT and DSA examinations were performed in 16 patients with liver cancer after TACE. Qualitative evaluations of the capability for detecting the remaining or recurrent viable tumor with DWI were performed by comparing enhanced-CT and DSA. ADCs and maximum CT enhancement value(HU) were measured(in 14 of the 16 patients)for lesions after TACE. And their relationships were investigated by comprehension correlative analysis. Results: Liver cancer after TACE presented variable signal intensities on DWI. The homogeneous accumulation of iodized oil observed on CT in 2 of 16 patients with liver cancer after TACE showed no tumor stain observed on DSA but with corresponding homogeneous hypointensity on DWI. The partial defects shown in accumulation of iodized oil in 2 of 16 patients represented the tumor stain on DSA corresponding to hyperintensities on DWI. None or faint accumulation of iodized oil areas in 12 of all patients, showed striking tumor stains corresponding to hyperintensities on DWI, and tumor necrosis had none or sight tumor stain on DSA, corresponding to hypointensities on DWI. A correlation between ADCs and maximum CT enhancement value (HU) of lesions after TACE was found (r=-0.76490, <0.05). Conclusion: Diffusion MRI is an useful method for detecting tumor remnant or recurrence of liver cancer after TACE, and can be used for the follow-up. (authors)

  6. Subcortical hyperintensity volumetrics in Alzheimer's disease and normal elderly in the Sunnybrook Dementia Study: correlations with atrophy, executive function, mental processing speed, and verbal memory.

    Science.gov (United States)

    Ramirez, Joel; McNeely, Alicia A; Scott, Christopher Jm; Stuss, Donald T; Black, Sandra E

    2014-01-01

    Subcortical hyperintensities (SHs) are radiological entities commonly observed on magnetic resonance imaging (MRI) of patients with Alzheimer's disease (AD) and normal elderly controls. Although the presence of SH is believed to indicate some form of subcortical vasculopathy, pathological heterogeneity, methodological differences, and the contribution of brain atrophy associated with AD pathology have yielded inconsistent results in the literature. Using the Lesion Explorer (LE) MRI processing pipeline for SH quantification and brain atrophy, this study examined SH volumes of interest and cognitive function in a sample of patients with AD (n = 265) and normal elderly controls (n = 100) from the Sunnybrook Dementia Study. Compared with healthy controls, patients with AD were found to have less gray matter, less white matter, and more sulcal and ventricular cerebrospinal fluid (all significant, P deep white SH (dwSH) (P processing speed (P memory (P <0.01) in patients with AD. These brain-behavior relationships and correlations with brain atrophy suggest that subtle, yet measurable, signs of small vessel disease may have potential clinical relevance as targets for treatment in Alzheimer's dementia.

  7. Diffusion-weighted imaging findings on MRI as the sole radiographic findings in a child with proven herpes simplex encephalitis

    Energy Technology Data Exchange (ETDEWEB)

    Obeid, Makram; Franklin, Jeremy; Shrestha, Shraddha; Johnson, Lara; Hurst, Daniel [Texas Tech University Health Sciences Center, Department of Pediatrics, Lubbock, TX (United States); Quattromani, Frank [Texas Tech University Health Sciences Center, Department of Radiology, Lubbock, TX (United States)

    2007-11-15

    We present a case of herpes simplex encephalitis in an 8-year-old girl, in whom hyperintensity was detected on diffusion-weighted imaging (DWI) while conventional MRI sequences were normal 1 week after the onset of neurological symptoms. This case is rare in that a child beyond the neonatal period with focal herpes simplex encephalitis had an abnormal DWI sequence as the only MRI finding. (orig.)

  8. Abnormal topological organization in white matter structural networks revealed by diffusion tensor tractography in unmedicated patients with obsessive-compulsive disorder.

    Science.gov (United States)

    Zhong, Zhaoxi; Zhao, Tengda; Luo, Jia; Guo, Zhihua; Guo, Meng; Li, Ping; Sun, Jing; He, Yong; Li, Zhanjiang

    2014-06-03

    Obsessive-compulsive disorder (OCD) is a chronic psychiatric disorder defined by recurrent thoughts, intrusive and distressing impulses, or images and ritualistic behaviors. Although focal diverse regional abnormalities white matter integrity in specific brain regions have been widely studied in populations with OCD, alterations in the structural connectivities among them remain poorly understood. The aim was to investigate the abnormalities in the topological efficiency of the white matter networks and the correlation between the network metrics and Yale-Brown Obsessive-Compulsive Scale scores in unmedicated OCD patients, using diffusion tensor tractography and graph theoretical approaches. This study used diffusion tensor imaging and deterministic tractography to map the white matter structural networks in 26 OCD patients and 39 age- and gender-matched healthy controls; and then applied graph theoretical methods to investigate abnormalities in the global and regional properties of the white matter network in these patients. The patients and control participants both showed small-world organization of the white matter networks. However, the OCD patients exhibited significant abnormal global topology, including decreases in global efficiency (t = -2.32, p = 0.02) and increases in shortest path length, Lp (t = 2.30, p = 0.02), the normalized weighted shortest path length, λ (t = 2.08, p=0.04), and the normalized clustering coefficient, γ (t = 2.26, p = 0.03), of their white matter structural networks compared with healthy controls. Further, the OCD patients showed a reduction in nodal efficiency predominately in the frontal regions, the parietal regions and caudate nucleus. The normalized weighted shortest path length of the network metrics was significantly negatively correlated with obsessive subscale of the Yale-Brown Obsessive-Compulsive Scale (r = -0.57, p = 0.0058). These findings demonstrate the abnormal topological efficiency in the white matter networks

  9. White matter microstructure predicts longitudinal social cognitive outcomes after paediatric traumatic brain injury: a diffusion tensor imaging study.

    Science.gov (United States)

    Ryan, N P; Genc, S; Beauchamp, M H; Yeates, K O; Hearps, S; Catroppa, C; Anderson, V A; Silk, T J

    2018-03-01

    Deficits in social cognition may be among the most profound and disabling sequelae of paediatric traumatic brain injury (TBI); however, the neuroanatomical correlates of longitudinal outcomes in this domain remain unexplored. This study aimed to characterize social cognitive outcomes longitudinally after paediatric TBI, and to evaluate the use of sub-acute diffusion tensor imaging (DTI) to predict these outcomes. The sample included 52 children with mild complex-severe TBI who were assessed on cognitive theory of mind (ToM), pragmatic language and affective ToM at 6- and 24-months post-injury. For comparison, 43 typically developing controls (TDCs) of similar age and sex were recruited. DTI data were acquired sub-acutely (mean = 5.5 weeks post-injury) in a subset of 65 children (TBI = 35; TDC = 30) to evaluate longitudinal prospective relationships between white matter microstructure assessed using Tract-Based Spatial Statistics and social cognitive outcomes. Whole brain voxel-wise analysis revealed significantly higher mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) in the sub-acute TBI group compared with TDC, with differences observed predominantly in the splenium of the corpus callosum (sCC), sagittal stratum (SS), dorsal cingulum (DC), uncinate fasciculus (UF) and middle and superior cerebellar peduncles (MCP & SCP, respectively). Relative to TDCs, children with TBI showed poorer cognitive ToM, affective ToM and pragmatic language at 6-months post-insult, and those deficits were related to abnormal diffusivity of the sCC, SS, DC, UF, MCP and SCP. Moreover, children with TBI showed poorer affective ToM and pragmatic language at 24-months post-injury, and those outcomes were predicted by sub-acute alterations in diffusivity of the DC and MCP. Abnormal microstructure within frontal-temporal, limbic and cerebro-cerebellar white matter may be a risk factor for long-term social difficulties observed in children with TBI. DTI may have

  10. Edge Contrast of the FLAIR Hyperintense Region Predicts Survival in Patients with High-Grade Gliomas following Treatment with Bevacizumab.

    Science.gov (United States)

    Bahrami, N; Piccioni, D; Karunamuni, R; Chang, Y-H; White, N; Delfanti, R; Seibert, T M; Hattangadi-Gluth, J A; Dale, A; Farid, N; McDonald, C R

    2018-04-05

    Treatment with bevacizumab is standard of care for recurrent high-grade gliomas; however, monitoring response to treatment following bevacizumab remains a challenge. The purpose of this study was to determine whether quantifying the sharpness of the fluid-attenuated inversion recovery hyperintense border using a measure derived from texture analysis-edge contrast-improves the evaluation of response to bevacizumab in patients with high-grade gliomas. MRIs were evaluated in 33 patients with high-grade gliomas before and after the initiation of bevacizumab. Volumes of interest within the FLAIR hyperintense region were segmented. Edge contrast magnitude for each VOI was extracted using gradients of the 3D FLAIR images. Cox proportional hazards models were generated to determine the relationship between edge contrast and progression-free survival/overall survival using age and the extent of surgical resection as covariates. After bevacizumab, lower edge contrast of the FLAIR hyperintense region was associated with poorer progression-free survival ( P = .009) and overall survival ( P = .022) among patients with high-grade gliomas. Kaplan-Meier curves revealed that edge contrast cutoff significantly stratified patients for both progression-free survival (log-rank χ 2 = 8.3, P = .003) and overall survival (log-rank χ 2 = 5.5, P = .019). Texture analysis using edge contrast of the FLAIR hyperintense region may be an important predictive indicator in patients with high-grade gliomas following treatment with bevacizumab. Specifically, low FLAIR edge contrast may partially reflect areas of early tumor infiltration. This study adds to a growing body of literature proposing that quantifying features may be important for determining outcomes in patients with high-grade gliomas. © 2018 by American Journal of Neuroradiology.

  11. The value of qualitative and quantitative assessment of lesion to cerebral cortex signal ratio on double inversion recovery sequence in the differentiation of demyelinating plaques from non-specific T2 hyperintensities

    Energy Technology Data Exchange (ETDEWEB)

    Hamcan, Salih; Battal, Bilal; Akgun, Veysel; Sari, Sebahattin; Tasar, Mustafa [Gulhane Military Medical School, Department of Radiology, Etlik, Ankara (Turkey); Oz, Oguzhan; Tasdemir, Serdar [Gulhane Military Medical School, Department of Neurology, Ankara (Turkey); Bozkurt, Yalcin [Golcuk Military Hospital, Department of Radiology, Kocaeli (Turkey)

    2017-02-15

    To assess the usefulness of the visual assessment and to determine diagnostic value of the lesion-to-cerebral cortex signal ratio (LCSR) measurement in the differentiation of demyelinating plaques and non-specific T2 hyperintensities on double inversion recovery (DIR) sequence. DIR and fluid-attenuated inversion recovery (FLAIR) sequences of 25 clinically diagnosed multiple sclerosis (MS) patients and 25 non-MS patients with non-specific T2-hyperintense lesions were evaluated visually and LCSRs were measured by two observers independently. On DIR sequence, the calculated mean LCSR ± SD for demyelinating plaques and non-specific T2-hyperintense lesions were 1.60 ± 0.26 and 0.75 ± 0.19 for observer1, and 1.61 ± 0.27 and 0.74 ± 0.19 for observer2. LCSRs of demyelinating plaques were significantly higher than other non-specific T2-hyperintense lesions on DIR sequence. By using the visual assessment demyelinating plaques were differentiated from non-specific T2-hyperintensities with 92.8 % sensitivity, 97.5 % specificity and 95.1 % accuracy for observer1 and 92.8 % sensitivity, 95 % specificity and 93.9 % accuracy for observer2. Visual assessment and LCSR measurement on DIR sequence seems to be useful for differentiating demyelinating MS plaques from supratentorial non-specific T2 hyperintensities. This feature can be used for diagnosis of MS particularly in patients with only supratentorial T2-hyperintense lesions who are categorized as radiologically possible MS. (orig.)

  12. Study of white matter at the centrum semiovale level with magnetic resonance spectroscopy and diffusion tensor imaging in cerebral small vessel disease.

    Science.gov (United States)

    Huang, L A; Ling, X Y; Li, C; Zhang, S J; Chi, G B; Xu, A D

    2014-04-08

    White matter lesion (WML) in magnetic resonance imaging is commonly observed in patients with cerebral small vessel disease (SVD), but the pathological mechanism of WML in SVD is still unclear. We observed the metabolism and microscopic anatomy of white matter in SVD patients. Twelve subjects clinically diagnosed with SVD and 6 normal control subjects were examined with magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI). The white matter at the centrum semiovale level was selected as the region of interest (ROI). The ROI metabolism parameters, including N-acetyl-l-aspartic acid (NAA), creatine (Cr), and choline (Cho) were measured by MRS. Microscopic parameters such as mean diffusion (MD) and fractional anisotropy (FA) in ROI were obtained by DTI. Compared with the normal control group, bilateral MD values in the SVD group were significantly elevated, whereas bilateral FA values in SVD were decreased, but the difference was not statistically significant. Additionally, NAA/Cho, Cho/Cr, and NAA/Cr showed no significant statistical differences. Our study suggests that the mechanisms of the SVD cognitive impairment are related to damage of the white matter structures rather than to brain metabolism.

  13. Gray and white matter asymmetries in healthy individuals aged 21-29 years: a voxel-based morphometry and diffusion tensor imaging study.

    Science.gov (United States)

    Takao, Hidemasa; Abe, Osamu; Yamasue, Hidenori; Aoki, Shigeki; Sasaki, Hiroki; Kasai, Kiyoto; Yoshioka, Naoki; Ohtomo, Kuni

    2011-10-01

    The hemispheres of the human brain are functionally and structurally asymmetric. The study of structural asymmetries provides important clues to the neuroanatomical basis of lateralized brain functions. Previous studies have demonstrated age-related changes in morphology and diffusion properties of brain tissue. In this study, we simultaneously explored gray and white matter asymmetry using voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) in 109 young healthy individuals (58 females and 51 males). To eliminate the potential confounding effects of aging and handedness, we restricted the study to right-handed subjects aged 21-29 years. VBM and voxel-based analysis of fractional anisotropy (FA) maps derived from DTI revealed a number of gray matter volume asymmetries (including the right frontal and left occipital petalias and leftward asymmetry of the planum temporale) and white matter FA asymmetries (including leftward asymmetry of the arcuate fasciculus, cingulum, and corticospinal tract). There was no significant effect of sex on gray and white matter asymmetry. Leftward volume asymmetry of the planum temporale and leftward FA asymmetry of the arcuate fasciculus were simultaneously demonstrated. Post hoc analysis showed that the gray matter volume of the planum temporale and FA of the arcuate fasciculus were positively related (Pearson correlation coefficient, 0.43; P < 0.0001). The results of our study demonstrate gray and white matter asymmetry in right-handed healthy young adults and suggest that leftward volume asymmetry of the planum temporale and leftward FA asymmetry of the arcuate fasciculus may be related. Copyright © 2010 Wiley-Liss, Inc.

  14. Sequential Magnetic Resonance Imaging Finding of Intramedullary Spinal Cord Abscess including Diffusion Weighted Image: a Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Jae Eun; Lee, Seung Young; Cha, Sang Hoon; Cho, Bum Sang; Jeon, Min Hee; Kang, Min Ho [Chungbuk National University College of Medicine, Cheongju (Korea, Republic of)

    2011-04-15

    Intramedullary spinal cord abscess (ISCA) is a rare infection of the central nervous system. We describe the magnetic resonance imaging (MRI) findings, including the diffusion-weighted imaging (DWI) findings, of ISCA in a 78-year-old man. The initial conventional MRI of the thoracic spine demonstrated a subtle enhancing nodule accompanied by significant edema. On the follow-up MRI after seven days, the nodule appeared as a ring-enhancing nodule. The non-enhancing central portion of the nodule appeared hyperintense on DWI with a decreased apparent diffusion coefficient (ADC) value on the ADC map. We performed myelotomy and surgical drainage, and thick, yellowish pus was drained

  15. Study on diffusion anisotropy of cerebral ischemia using diffusion weighted echo-planar MRI

    International Nuclear Information System (INIS)

    Kajima, Toshio

    1997-01-01

    Focal cerebral ischemia was produced by occlusion of the intracranial main cerebral artery with a silicone cylinder in Wistar rats. Diffusion-weighted echo-planar images (DW-EPls) using the motion-probing gradient (MPG) method were acquired at 1-3 hours and 24-48 hours after occlusion. Apparent diffusion coefficients (ADCs) were calculated from these images in ischemic lesions and in normal unoccluded regions. Results were as follows. Ischemic lesions could be detected on the DW-EPIs at 1 hour after occlusion. The ADC of water in the brain tissue was smaller than that of free water as a result of restricted diffusion. Anisotropic diffusion that probably can be attributed to the myelin sheath was observed in the normal white matter. In the ischemic lesions, the ADC decreased rapidly within 1-3 hours after occlusion and then decreased gradually after 24-48 hours. In the ischemic white matter, diffusion anisotropy disappeared at 24-48 hours after occlusion. Diffusion-weighted imaging may have applications in the examination of pathophysiological mechanisms in cerebral ischemia by means of evaluation of ADC and diffusion anisotropy. (author)

  16. On the diffusion of innovations: A structural perspective

    DEFF Research Database (Denmark)

    Ostoic, Antonio Rivero

    2010-01-01

    Working paper describing structural models for the analysis of the diffusion of innovations and mechanisms for adoption. Additionally, some milestones in the study of innovation diffusion are given and a discussion of this matter.......Working paper describing structural models for the analysis of the diffusion of innovations and mechanisms for adoption. Additionally, some milestones in the study of innovation diffusion are given and a discussion of this matter....

  17. DTI and VBM reveal white matter changes without associated gray matter changes in patients with idiopathic restless legs syndrome

    Science.gov (United States)

    Belke, Marcus; Heverhagen, Johannes T; Keil, Boris; Rosenow, Felix; Oertel, Wolfgang H; Stiasny-Kolster, Karin; Knake, Susanne; Menzler, Katja

    2015-01-01

    Background and Purpose We evaluated cerebral white and gray matter changes in patients with iRLS in order to shed light on the pathophysiology of this disease. Methods Twelve patients with iRLS were compared to 12 age- and sex-matched controls using whole-head diffusion tensor imaging (DTI) and voxel-based morphometry (VBM) techniques. Evaluation of the DTI scans included the voxelwise analysis of the fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD). Results Diffusion tensor imaging revealed areas of altered FA in subcortical white matter bilaterally, mainly in temporal regions as well as in the right internal capsule, the pons, and the right cerebellum. These changes overlapped with changes in RD. Voxel-based morphometry did not reveal any gray matter alterations. Conclusions We showed altered diffusion properties in several white matter regions in patients with iRLS. White matter changes could mainly be attributed to changes in RD, a parameter thought to reflect altered myelination. Areas with altered white matter microstructure included areas in the internal capsule which include the corticospinal tract to the lower limbs, thereby supporting studies that suggest changes in sensorimotor pathways associated with RLS. PMID:26442748

  18. Diffusion-weighted MR and apparent diffusion coefficient in the evaluation of severe brain injury

    International Nuclear Information System (INIS)

    Nakahara, M.; Ericson, K.; Bellander, B.M.

    2001-01-01

    Purpose: To study apparent diffusion coefficient (ADC) maps in severely brain-injured patients. Material and Methods: Four deeply comatose patients with severe brain injury were investigated with single-shot, diffusion-weighted, spin-echo echo planar imaging. The tetrahedral diffusion gradient configuration and four iterations of a set of b-values (one time of 0 mm2/s, and four times of 1000 mm2/s) were used to create isotropic ADC maps with high signal-to-noise ratio. ADC values of gray and white matter were compared among patients and 4 reference subjects. Results: one patient was diagnosed as clinically brain dead after the MR examination. The patient's ADC values of gray and white matter were significantly lower than those of 3 other brain-injured patients. In addition the ADC value of white matter was significantly lower than that of gray matter. Conclusion: The patient with fatal outcome shortly after MR examination differed significantly from other patients with severe brain injury but non-fatal outcome, with regard to ADC values in gray and white matter. This might indicate a prognostic value of ADC maps in the evaluation of traumatic brain injury

  19. White matter structure and clinical characteristics of stroke patients: A diffusion tensor MRI study.

    Science.gov (United States)

    Ueda, Ryo; Yamada, Naoki; Kakuda, Wataru; Abo, Masahiro; Senoo, Atsushi

    2016-03-15

    Fractional anisotropy has been used in many studies that examined post-stroke changes in white matter. This study was performed to clarify cerebral white matter changes after stroke using generalized fractional anisotropy (GFA). White matter structure was visualized using diffusion tensor imaging in 72 patients with post-stroke arm paralysis. Exercise-related brain regions were examined in cerebral white matter using GFA. The relationship between GFA and clinical characteristics was examined. Overall, the mean GFA of the lesioned hemisphere was significantly lower than that of the non-lesioned hemisphere (PBrodmann area 5 of the non-lesioned hemisphere. Age correlated negatively with GFA in Brodmann areas 5 and 7 of the lesioned hemisphere. Though these results may be due to a decrease in the frequency of use of the paralyzed limb over time, GFA overall was significantly and negatively affected by the subject's age. The GFA values of patients with paralysis of the dominant hand were significantly different from those of patients with paralysis of the nondominant hand in Brodmann areas 4 and 6 of the non-lesioned hemisphere and Brodmann area 4 of the lesioned hemisphere (P<0.05). The stroke size and location were not associated with GFA differences. Differences between the GFA of the lesioned and non-lesioned hemispheres varied depending on the affected brain region, age at onset of paralysis, and paralysis of the dominant or non-dominant hand. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Altered Development of White Matter in Youth at High Familial Risk for Bipolar Disorder: A Diffusion Tensor Imaging Study

    Science.gov (United States)

    Versace, Amelia; Ladouceur, Cecile D.; Romero, Soledad; Birmaher, Boris; Axelson, David A.; Kupfer, David J.; Phillips, Mary L.

    2010-01-01

    Objective: To study white matter (WM) development in youth at high familial risk for bipolar disorder (BD). WM alterations are reported in youth and adults with BD. WM undergoes important maturational changes in adolescence. Age-related changes in WM microstructure using diffusion tensor imaging with tract-based spatial statistics in healthy…

  1. Diffuse alterations in grey and white matter associated with cognitive impairment in Shwachman–Diamond syndrome: Evidence from a multimodal approach

    Directory of Open Access Journals (Sweden)

    Sandra Perobelli

    2015-01-01

    Cognitive impairment in Shwachman–Diamond syndrome subjects is associated with diffuse brain anomalies in the grey matter (verbal skills with BA44 and BA20 in the right hemisphere; perceptual skills with BA5, 37, 20, 21, 42 in the left hemisphere and white matter connectivity (verbal skills with alterations in the fronto-occipital fasciculus and with the inferior-longitudinal fasciculus; perceptual skills with the arcuate fasciculus, limbic and ponto-cerebellar fasciculus; memory skills with the arcuate fasciculus; executive functions with the anterior cingulated and arcuate fasciculus.

  2. Combined fetal inflammation and postnatal hypoxia causes myelin deficits and autism-like behavior in a rat model of diffuse white matter injury.

    Science.gov (United States)

    van Tilborg, Erik; Achterberg, E J Marijke; van Kammen, Caren M; van der Toorn, Annette; Groenendaal, Floris; Dijkhuizen, Rick M; Heijnen, Cobi J; Vanderschuren, Louk J M J; Benders, Manon N J L; Nijboer, Cora H A

    2018-01-01

    Diffuse white matter injury (WMI) is a serious problem in extremely preterm infants, and is associated with adverse neurodevelopmental outcome, including cognitive impairments and an increased risk of autism-spectrum disorders. Important risk factors include fetal or perinatal inflammatory insults and fluctuating cerebral oxygenation. However, the exact mechanisms underlying diffuse WMI are not fully understood and no treatment options are currently available. The use of clinically relevant animal models is crucial to advance knowledge on the pathophysiology of diffuse WMI, allowing the definition of novel therapeutic targets. In the present study, we developed a multiple-hit animal model of diffuse WMI by combining fetal inflammation and postnatal hypoxia in rats. We characterized the effects on white matter development and functional outcome by immunohistochemistry, MRI and behavioral paradigms. Combined fetal inflammation and postnatal hypoxia resulted in delayed cortical myelination, microglia activation and astrogliosis at P18, together with long-term changes in oligodendrocyte maturation as observed in 10 week old animals. Furthermore, rats with WMI showed impaired motor performance, increased anxiety and signs of autism-like behavior, i.e. reduced social play behavior and increased repetitive grooming. In conclusion, the combination of fetal inflammation and postnatal hypoxia in rats induces a pattern of brain injury and functional impairments that closely resembles the clinical situation of diffuse WMI. This animal model provides the opportunity to elucidate pathophysiological mechanisms underlying WMI, and can be used to develop novel treatment options for diffuse WMI in preterm infants. © 2017 The Authors GLIA Published by Wiley Periodicals, Inc.

  3. Long-term effects of radiation therapy on white matter of the corpus callosum: a diffusion tensor imaging study in children

    Energy Technology Data Exchange (ETDEWEB)

    Makola, Monwabisi [University of Cincinnati, College of Medicine, Cincinnati, OH (United States); Douglas Ris, M. [Texas Children' s Hospital, Department of Pediatrics, Baylor College of Medicine, Houston, TX (United States); Mahone, E.M. [Kennedy Krieger Institute, Department of Neuropsychology, Baltimore, MD (United States); Johns Hopkins University School of Medicine, Department of Psychiatry and Behavioral Sciences, Baltimore, MD (United States); Yeates, Keith Owen [University of Calgary, Department of Psychology, Alberta Children' s Hospital Research Institute, Hotchkiss Brain Institute, Calgary, AB (Canada); Cecil, Kim M. [Imaging Research Center, Cincinnati Children' s Hospital Medical Center, Cincinnati, OH (United States); University of Cincinnati College of Medicine, Department of Radiology, Cincinnati, OH (United States); University of Cincinnati College of Medicine, Department of Pediatrics, Cincinnati, OH (United States); University of Cincinnati College of Medicine, Neuroscience Graduate Program, Cincinnati, OH (United States); University of Cincinnati College of Medicine, Department of Environmental Health, Cincinnati, OH (United States)

    2017-12-15

    Despite improving survival rates, children are at risk for long-term cognitive and behavioral difficulties following the diagnosis and treatment of a brain tumor. Surgery, chemotherapy and radiation therapy have all been shown to impact the developing brain, especially the white matter. The purpose of this study was to determine the long-term effects of radiation therapy on white matter integrity, as measured by diffusion tensor imaging, in pediatric brain tumor patients 2 years after the end of radiation treatment, while controlling for surgical interventions. We evaluated diffusion tensor imaging performed at two time points: a baseline 3 to 12 months after surgery and a follow-up approximately 2 years later in pediatric brain tumor patients. A region of interest analysis was performed within three regions of the corpus callosum. Diffusion tensor metrics were determined for participants (n=22) who underwent surgical tumor resection and radiation therapy and demographically matched with participants (n=22) who received surgical tumor resection only. Analysis revealed that 2 years after treatment, the radiation treated group exhibited significantly lower fractional anisotropy and significantly higher radial diffusivity within the body of the corpus callosum compared to the group that did not receive radiation. The findings indicate that pediatric brain tumor patients treated with radiation therapy may be at greater risk of experiencing long-term damage to the body of the corpus callosum than those treated with surgery alone. (orig.)

  4. Long-term effects of radiation therapy on white matter of the corpus callosum: a diffusion tensor imaging study in children

    International Nuclear Information System (INIS)

    Makola, Monwabisi; Douglas Ris, M.; Mahone, E.M.; Yeates, Keith Owen; Cecil, Kim M.

    2017-01-01

    Despite improving survival rates, children are at risk for long-term cognitive and behavioral difficulties following the diagnosis and treatment of a brain tumor. Surgery, chemotherapy and radiation therapy have all been shown to impact the developing brain, especially the white matter. The purpose of this study was to determine the long-term effects of radiation therapy on white matter integrity, as measured by diffusion tensor imaging, in pediatric brain tumor patients 2 years after the end of radiation treatment, while controlling for surgical interventions. We evaluated diffusion tensor imaging performed at two time points: a baseline 3 to 12 months after surgery and a follow-up approximately 2 years later in pediatric brain tumor patients. A region of interest analysis was performed within three regions of the corpus callosum. Diffusion tensor metrics were determined for participants (n=22) who underwent surgical tumor resection and radiation therapy and demographically matched with participants (n=22) who received surgical tumor resection only. Analysis revealed that 2 years after treatment, the radiation treated group exhibited significantly lower fractional anisotropy and significantly higher radial diffusivity within the body of the corpus callosum compared to the group that did not receive radiation. The findings indicate that pediatric brain tumor patients treated with radiation therapy may be at greater risk of experiencing long-term damage to the body of the corpus callosum than those treated with surgery alone. (orig.)

  5. MR imaging evidence of anisotropic diffusion in the cat brain

    International Nuclear Information System (INIS)

    Moseley, M.E.; Mintorovich, J.; Cohen, Y.; Chilevitt, L.; Tsuruda, J.; Norman, D.; Weinstein, P.

    1989-01-01

    This paper discusses a study of diffusion behavior of brain water in the cat. Diffusion-weighted images, acquired with large gradient b values of 1,000-2,000 sec/mm 2 , showed no clear evidence of anisotropic water diffusion in either gray matter or basal ganglia. Large directional differences in image intensities and diffusion values were observed in cortical and deep white matter. Faster diffusion was sen when the direction of the applied diffusion gradient was parallel to the orientation of the white matter. Diffusion perpendicular to the gradient direction was significantly lower. This effect was proportional to gradient duration and strength and was seen in both pre- and immediate post-mortem images in all axial, sagittal, and coronal images

  6. Contribution to the study of the mechanisms of turbulent diffusion and of related matters

    International Nuclear Information System (INIS)

    Mailliat, Alain.

    1980-12-01

    The subject of this paper is the study of turbulent diffusion mechanisms and the related problems. The diffusion mechanisms considered here are those which concern a passive scalar contaminant not subject to molecular effects. The reason for this latter character is that it makes it possible to isolate in the diffusion phenomenon that which is inherent in the turbulent dispersion. The present state of this question is reviewed in Chapter I. The system of natural coordinates for following the movement of a particle and hence for describing the dispersion is that of Lagrange. For our purpose this description must be statistical. Hence, the specific properties of the probability densities of the velocities and movements in this type of coordinate are examined in Chapter II. The expressions of the probability densities of the concentration and turbulent flow of a contaminant are sought. These expressions make it possible to formulate the diffusion laws linking the mean flow and concentration to the statistical characteristics of the velocity field. These matters form the central subject of this paper and are developed in Chapter III. Although the use of Lagrange's coordinates makes it possible fairly easily to obtain the probability densities mentioned above, it does, on the other hand, rule out on examination the relations existing between Lagrangian and Eulerian probability characteristics of the velocity field moments. The experimental determination in a Lagrangian system of the probability characteristics is in fact very tricky. These questions are discussed in Chapter IV of this paper [fr

  7. Longitudinal diffusion tensor magnetic resonance imaging study of radiation-induced white matter damage in a rat model.

    Science.gov (United States)

    Wang, Silun; Wu, Ed X; Qiu, Deqiang; Leung, Lucullus H T; Lau, Ho-Fai; Khong, Pek-Lan

    2009-02-01

    Radiation-induced white matter (WM) damage is a major side effect of whole brain irradiation among childhood cancer survivors. We evaluate longitudinally the diffusion characteristics of the late radiation-induced WM damage in a rat model after 25 and 30 Gy irradiation to the hemibrain at 8 time points from 2 to 48 weeks postradiation. We hypothesize that diffusion tensor magnetic resonance imaging (DTI) indices including fractional anisotropy (FA), trace, axial diffusivity (lambda(//)), and radial diffusivity (lambda( perpendicular)) can accurately detect and monitor the histopathologic changes of radiation-induced WM damage, measured at the EC, and that these changes are dose and time dependent. Results showed a progressive reduction of FA, which was driven by reduction in lambda(//) from 4 to 40 weeks postradiation, and an increase in lambda( perpendicular) with return to baseline in lambda(//) at 48 weeks postradiation. Histologic evaluation of irradiated WM showed reactive astrogliosis from 4 weeks postradiation with reversal at 36 weeks, and demyelination, axonal degeneration, and necrosis at 48 weeks postradiation. Moreover, changes in lambda(//) correlated with reactive astrogliosis (P histopathologic changes of WM damage and our results support the use of DTI as a biomarker to noninvasively monitor radiation-induced WM damage.

  8. Deep versus periventricular white matter lesions and cognitive function in a community sample of middle-aged participants.

    Science.gov (United States)

    Soriano-Raya, Juan José; Miralbell, Júlia; López-Cancio, Elena; Bargalló, Núria; Arenillas, Juan Francisco; Barrios, Maite; Cáceres, Cynthia; Toran, Pere; Alzamora, Maite; Dávalos, Antoni; Mataró, Maria

    2012-09-01

    The association of cerebral white matter lesions (WMLs) with cognitive status is not well understood in middle-aged individuals. Our aim was to determine the specific contribution of periventricular hyperintensities (PVHs) and deep white matter hyperintensities (DWMHs) to cognitive function in a community sample of asymptomatic participants aged 50 to 65 years. One hundred stroke- and dementia-free adults completed a comprehensive neuropsychological battery and brain MRI protocol. Participants were classified according to PVH and DWMH scores (Fazekas scale). We dichotomized our sample into low grade WMLs (participants without or with mild lesions) and high grade WMLs (participants with moderate or severe lesions). Analyses were performed separately in PVH and DWMH groups. High grade DWMHs were associated with significantly lower scores in executive functioning (-0.45 standard deviations [SD]), attention (-0.42 SD), verbal fluency (-0.68 SD), visual memory (-0.52 SD), visuospatial skills (-0.79 SD), and psychomotor speed (-0.46 SD). Further analyses revealed that high grade DWMHs were also associated with a three- to fourfold increased risk of impaired scores (i.e.,<1.5 SD) in executive functioning, verbal fluency, visuospatial skills, and psychomotor speed. Our findings suggest that only DWMHs, not PVHs, are related to diminished cognitive function in middle-aged individuals. (JINS, 2012, 18, 1-12).

  9. 1H MR spectroscopy of gray and white matter in carbon monoxide poisoning

    DEFF Research Database (Denmark)

    Kondziella, D.; Danielsen, E.R.; Hansen, K.

    2009-01-01

    Carbon monoxide (CO) intoxication leads to acute and chronic neurological deficits, but little is known about the specific noxious mechanisms. (1)H magnetic resonance spectroscopy (MRS) may allow insight into the pathophysiology of CO poisoning by monitoring neurochemical disturbances, yet only......, magnetic resonance imaging (MRI) and neuropsychological testing. Five patients suffered from acute high-dose CO intoxication and were in coma for 1-6 days. In these patients, MRI revealed hyperintensities of the white matter and globus pallidus and also showed increased choline (Cho) and decreased N...

  10. Diffusion-weighted MRI in shaken baby syndrome

    International Nuclear Information System (INIS)

    Chan, Yu-Leung; Chu, Winnie C.W.; Wong, Gary W.K.; Yeung, David K.W.

    2003-01-01

    We present the characteristic CT and MRI findings of a 2-month-old girl with shaken baby syndrome. Diffusion-weighted MR imaging performed 8 days after the insult established the presence of injury to the white matter in the corpus callosum and subcortical white matter in the temporo-occipito-parietal region. Diffusion-weighted MR imaging is valuable in the diagnostic work-up of suspected shaken baby syndrome, as injury to the white matter can be demonstrated days after the injury. (orig.)

  11. Oculomotor nerve palsy evaluated by diffusion-tensor tractography

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Kei; Kizu, Osamu; Ito, Hirotoshi; Nishimura, Tsunehiko [Kyoto Prefectural University of Medicine, Department of Radiology, Kyoto (Japan); Shiga, Kensuke; Akiyama, Katsuhisa; Nakagawa, Masanori [Kyoto Prefectural University of Medicine, Department of Neurology, Kyoto (Japan)

    2006-06-15

    The aim of the study was to test the feasibility of the tractography technique based on diffusion-tensor imaging (DTI) for the assessment of small infarcts involving the brainstem. A patient who presented with an isolated left third cranial nerve palsy underwent magnetic resonance examination. Images were obtained by use of a whole-body, 1.5-T imager. Data were transferred to an off-line workstation for fiber tracking. The conventional diffusion-weighted imaging (DWI) performed using a 5 mm slice thickness could only depict an equivocal hyperintensity lesion located at the left paramedian midbrain. An additional thin-slice DTI was performed immediately after the initial DWI using a 3 mm slice thickness and was able to delineate the lesion more clearly. Image postprocessing of thin-slice DTI data revealed that the lesion location involved the course of the third cranial nerve tract, corresponding with the patient's clinical symptoms. The tractography technique can be applied to assess fine neuronal structures of the brainstem, enabling direct clinicoradiological correlation of small infarcts involving this region. (orig.)

  12. Oculomotor nerve palsy evaluated by diffusion-tensor tractography

    International Nuclear Information System (INIS)

    Yamada, Kei; Kizu, Osamu; Ito, Hirotoshi; Nishimura, Tsunehiko; Shiga, Kensuke; Akiyama, Katsuhisa; Nakagawa, Masanori

    2006-01-01

    The aim of the study was to test the feasibility of the tractography technique based on diffusion-tensor imaging (DTI) for the assessment of small infarcts involving the brainstem. A patient who presented with an isolated left third cranial nerve palsy underwent magnetic resonance examination. Images were obtained by use of a whole-body, 1.5-T imager. Data were transferred to an off-line workstation for fiber tracking. The conventional diffusion-weighted imaging (DWI) performed using a 5 mm slice thickness could only depict an equivocal hyperintensity lesion located at the left paramedian midbrain. An additional thin-slice DTI was performed immediately after the initial DWI using a 3 mm slice thickness and was able to delineate the lesion more clearly. Image postprocessing of thin-slice DTI data revealed that the lesion location involved the course of the third cranial nerve tract, corresponding with the patient's clinical symptoms. The tractography technique can be applied to assess fine neuronal structures of the brainstem, enabling direct clinicoradiological correlation of small infarcts involving this region. (orig.)

  13. Role of thalamic diffusion for disease differentiation between multiple sclerosis and ischemic cerebral small vessel disease

    International Nuclear Information System (INIS)

    Oeztoprak, Bilge; Oeztoprak, Ibrahim; Salk, Ismail; Topalkara, Kamil; Erkoc, Mustafa F.

    2015-01-01

    Cerebral small vessel disease (CSVD) and multiple sclerosis (MS) both harbor multiple, T2-hyperintense white matter lesions on conventional magnetic resonance imaging (MRI).We aimed to determine the microstructural changes via diffusion-weighted imaging (DWI) in normal appearing thalami. We hypothesized that the apparent diffusion coefficient (ADC) values would be different in CSVD and MS, since the extent of arterial involvement is different in these two diseases. DWI was performed for 50 patients with CSVD and 35 patients with MS along with gender- and age-matched controls whose conventional MRI revealed normal findings. DWI was done with 1.5 Tesla MR devices using echo planar imaging (EPI) for b = 0, 1000 s/mm 2 . ADC values were obtained from the thalami which appeared normal on T2-weighted and FLAIR images. Standard oval regions of interest (ROIs) of 0.5 cm 2 which were oriented parallel to the long axis of the thalamus were used for this purpose. The mean ADC value of the thalamus was (0.99 ± 0.16) x 10 -3 mm 2 /s in patients with CSVD, whereas the mean ADC value was (0.78 ± 0.06) x 10 -3 mm 2 /s in the control group. The mean ADC value was significantly higher in patients with CSVD compared to the controls (p < 0.001). The mean ADC values of the thalamus were (0.78 ± 0.08) x 10 -3 mm 2 /s in MS patients, and (0.75 ± 0.08) x 10 -3 mm 2 /s in the control group, which are not significantly different (p > 0.05). Our study revealed a difference in the diffusion of the thalami between CSVD and MS. DWI may aid in the radiological disease differentiation. (orig.)

  14. Role of thalamic diffusion for disease differentiation between multiple sclerosis and ischemic cerebral small vessel disease

    Energy Technology Data Exchange (ETDEWEB)

    Oeztoprak, Bilge; Oeztoprak, Ibrahim; Salk, Ismail [Cumhuriyet University School of Medicine, Department of Radiology, Sivas (Turkey); Topalkara, Kamil [Bayindir Hospital, Department of Neurology, Ankara (Turkey); Erkoc, Mustafa F. [Bozok University School of Medicine, Department of Radiology, Yozgat (Turkey)

    2015-04-01

    Cerebral small vessel disease (CSVD) and multiple sclerosis (MS) both harbor multiple, T2-hyperintense white matter lesions on conventional magnetic resonance imaging (MRI).We aimed to determine the microstructural changes via diffusion-weighted imaging (DWI) in normal appearing thalami. We hypothesized that the apparent diffusion coefficient (ADC) values would be different in CSVD and MS, since the extent of arterial involvement is different in these two diseases. DWI was performed for 50 patients with CSVD and 35 patients with MS along with gender- and age-matched controls whose conventional MRI revealed normal findings. DWI was done with 1.5 Tesla MR devices using echo planar imaging (EPI) for b = 0, 1000 s/mm{sup 2}. ADC values were obtained from the thalami which appeared normal on T2-weighted and FLAIR images. Standard oval regions of interest (ROIs) of 0.5 cm{sup 2} which were oriented parallel to the long axis of the thalamus were used for this purpose. The mean ADC value of the thalamus was (0.99 ± 0.16) x 10{sup -3} mm{sup 2}/s in patients with CSVD, whereas the mean ADC value was (0.78 ± 0.06) x 10{sup -3} mm{sup 2}/s in the control group. The mean ADC value was significantly higher in patients with CSVD compared to the controls (p < 0.001). The mean ADC values of the thalamus were (0.78 ± 0.08) x 10{sup -3} mm{sup 2}/s in MS patients, and (0.75 ± 0.08) x 10{sup -3} mm{sup 2}/s in the control group, which are not significantly different (p > 0.05). Our study revealed a difference in the diffusion of the thalami between CSVD and MS. DWI may aid in the radiological disease differentiation. (orig.)

  15. Diffusion-weighted MR imaging of ring-enhancing intracerebral lesions

    International Nuclear Information System (INIS)

    Li Youcheng; Li Jiance; Tian Wei; Li Zongfang

    2005-01-01

    Objective: To assess the diagnostic value of diffusion-weighted echo-planar MR Imaging (DWI) in ring-enhancing intracerebral lesions. Methods: Magnetic resonance diffusion-weighted images of ninty-three patients presenting with ring-ehancing intracerebral lesions diagnosed by clinical or histopathologic findings were studied retrospectively, including 21 gliomas, 26 metastases, 13 pyogenic abscesses, 18 neurocysticercoses and 15 subacute intracerebral hematomas. The signal intensity ratio on diffusion-weighted images and exponential diffusion coefficient images was calculated respectively in ring walls, central contents, and perilesional edemas of ring-enhancing lesions, and normal contralateral cerebral parenchyma was used for comparison. ADC values of interest of lesions, contralateral cerebral parenchyma and CFS were calculated as well. Results: In pyogenic abscesses and subacute intracerebral hematomas, the central content was always extremely hyperintense on diffusion-weighted images, and showed low ADCs [(0.56 ± 0.20) x 10 -3 mm 2 /s, (0.69 ± 0.16) x 10 -3 mm 2 /s, respectively]. On the other hand the central content of gliomas, metastases and neurocysticercoses was hypointense, and showed high ADCs [(2.76 ± 0.41 ) x 10 -3 mm 2 /s, (2.31 ± 0.39 ) x 10 -3 mm 2 /s, (2.10 ± 0.32) x 10 -3 mm 2 /s, respectively]. The ADCs of the first two lesions were significantly lower than of the last three lesions (P 2 -weighted images should be reviewed in daily clinical practice. (authors)

  16. Evaluation of white matter integrity in systemic lupus erythematosus by diffusion tensor magnetic resonance imaging: a study using tract-based spatial statistics

    Energy Technology Data Exchange (ETDEWEB)

    Goulart Correa, Diogo; Ventura, Nina; Gasparetto, Emerson Leandro [Federal University of Rio de Janeiro, Department of Radiology, Hospital Universitario Clementino Fraga Filho, Rio de Janeiro, RJ (Brazil); Clinica de Diagnostico por Imagem (CDPI), Rio de Janeiro, RJ (Brazil); Zimmermann, Nicolle; Paz Fonseca, Rochele [Federal University of Rio de Janeiro, Department of Radiology, Hospital Universitario Clementino Fraga Filho, Rio de Janeiro, RJ (Brazil); Pontifical Catholic University of Rio Grande do Sul, Department of Psychology, Porto Alegre, RS (Brazil); Batista Pereira, Denis; Netto, Tania Maria [Federal University of Rio de Janeiro, Department of Radiology, Hospital Universitario Clementino Fraga Filho, Rio de Janeiro, RJ (Brazil); Doring, Thomas M. [Clinica de Diagnostico por Imagem (CDPI), Rio de Janeiro, RJ (Brazil)

    2016-08-15

    The aim of this study was to evaluate the white matter integrity in brains of patients with systemic lupus erythematosus (SLE) using a voxel-based analyses of diffusion tensor imaging (DTI) data. Fifty-seven patients with SLE were compared to 36 control patients who were matched by gender, age, education, and Mini Mental State Examination score. DTI was performed along 30 noncollinear directions in a 1.5 Tesla scanner. For tract-based spatial statistics (TBSS), a white matter skeleton was created, and a permutation-based inference with 5000 permutations and a threshold of p < 0.05 was used to identify abnormalities in fractional anisotropy (FA). The mean (MD), radial (RD), and axial diffusivities (AD) were also projected onto the mean FA skeleton. We found a significant decrease of global FA in SLE patients compared to controls. The areas of reduced FA included the right superior corona radiata, the right superior longitudinal fasciculus, the body of the corpus callosum, the right inferior fronto-occipital fasciculus, the right thalamic radiation, and the right uncinate fasciculus. Patients with SLE also had increased AD and RD in several areas. Substantial overlap of areas with increased AD and RD occurred and were spatially much more extensive than the areas of reduced FA. Significant increases of AD values were concordant to those of RD and MD and more extensive than FA changes. Analyzing all diffusivity parameters, using TBSS, can detect more white matter microstructural changes in patients with SLE than analyzing FA alone. (orig.)

  17. Evaluation of white matter integrity in systemic lupus erythematosus by diffusion tensor magnetic resonance imaging: a study using tract-based spatial statistics

    International Nuclear Information System (INIS)

    Goulart Correa, Diogo; Ventura, Nina; Gasparetto, Emerson Leandro; Zimmermann, Nicolle; Paz Fonseca, Rochele; Batista Pereira, Denis; Netto, Tania Maria; Doring, Thomas M.

    2016-01-01

    The aim of this study was to evaluate the white matter integrity in brains of patients with systemic lupus erythematosus (SLE) using a voxel-based analyses of diffusion tensor imaging (DTI) data. Fifty-seven patients with SLE were compared to 36 control patients who were matched by gender, age, education, and Mini Mental State Examination score. DTI was performed along 30 noncollinear directions in a 1.5 Tesla scanner. For tract-based spatial statistics (TBSS), a white matter skeleton was created, and a permutation-based inference with 5000 permutations and a threshold of p < 0.05 was used to identify abnormalities in fractional anisotropy (FA). The mean (MD), radial (RD), and axial diffusivities (AD) were also projected onto the mean FA skeleton. We found a significant decrease of global FA in SLE patients compared to controls. The areas of reduced FA included the right superior corona radiata, the right superior longitudinal fasciculus, the body of the corpus callosum, the right inferior fronto-occipital fasciculus, the right thalamic radiation, and the right uncinate fasciculus. Patients with SLE also had increased AD and RD in several areas. Substantial overlap of areas with increased AD and RD occurred and were spatially much more extensive than the areas of reduced FA. Significant increases of AD values were concordant to those of RD and MD and more extensive than FA changes. Analyzing all diffusivity parameters, using TBSS, can detect more white matter microstructural changes in patients with SLE than analyzing FA alone. (orig.)

  18. Longitudinal follow-up of individual white matter hyperintensities in a large cohort of elderly

    Energy Technology Data Exchange (ETDEWEB)

    Maillard, Pauline; Crivello, Fabrice; Tzourio-Mazoyer, Nathalie [Universite de Caen, Universite Paris Descartes, Centre d' Imagerie-Neurosciences et Applications aux Pathologies, CI-NAPS, UMR6232, CNRS, CEA, GIP Cyceron, Caen (France); Dufouil, Carole; Tzourio, Christophe [INSERM, Neuroepidemiologie U708, Paris (France); Mazoyer, Bernard [Universite de Caen, Universite Paris Descartes, Centre d' Imagerie-Neurosciences et Applications aux Pathologies, CI-NAPS, UMR6232, CNRS, CEA, GIP Cyceron, Caen (France); Institut Universitaire de France, Paris (France); CHU, GIP Cyceron, Caen (France)

    2009-04-15

    We report on a method for the longitudinal follow-up of individual white matter hypersignals (WMH) and on its application to the study of WMH natural evolution in a cohort of 1,118 elderly over a 4-year period. For each subject, automated WMH detection was performed on T2-weighted MR images acquired both at baseline and at follow-up after registration in a common space. The detection algorithm was designed both to track WMH previously existing at baseline and to identify newly formed WMH. The average annual change in WMH load was found to be 0.25 cm{sup 3}/year, 36% of this change being attributable to newly formed WMH. Quantitative analyses showed that change in WMH was mainly explained by progression of juxtaventricular and periventricular WMH while the load of WMH in the deep white matter zones was found stable over 4 years of the study. Statistical parametric mapping confirmed these spatial WMH change distributions in the juxta- and periventricular zones. High blood pressure was not a significant predictor of the annual change in WMH. This study proposes a new scheme for the longitudinal study of WMH change by dissociating worsening of existent WMH from surfacing of new WMH and may thus contribute to help understanding and characterizing the neurological and etiological bases of these two processes and their potential differences. (orig.)

  19. Differences in supratentorial white matter diffusion after radiotherapy - New biomarker of normal brain tissue damage?

    Energy Technology Data Exchange (ETDEWEB)

    Ravn, Soeren; Jens Broendum Froekaer, Jens [Dept. of Radiology, Aalborg Univ. Hospital, Aalborg (Denmark)], e-mail: sorl@rn.dk; Holmberg, Mats [Dept. of Oncology, Aalborg Univ. Hospital, Aalborg (Denmark); Soerensen, Preben [Dept. of Neurosurgery, Aalborg Univ. Hospital, Aalborg (Denmark); Carl, Jesper [Dept. of Neurosurgery, Aalborg Univ. Hospital, Aalborg (Denmark)

    2013-10-15

    Introduction: Therapy-induced injury to normal brain tissue is a concern in the treatment of all types of brain tumours. The purpose of this study was to investigate if magnetic resonance diffusion tensor imaging (DTI) could serve as a potential biomarker for the assessment of radiation-induced long-term white matter injury. Material and methods: DTI- and T1-weighted images of the brain were obtained in 19 former radiotherapy patients [nine men and 10 women diagnosed with astrocytoma (4), pituitary adenoma (6), meningioma (8) and craniopharyngioma (1), average age 57.8 (range 35-71) years]. Average time from radiotherapy to DTI scan was 4.6 (range 2.0-7.1) years. NordicICE software (NIC) was used to calculate apparent diffusion coefficient maps (ADC-maps). The co-registration between T1 images and ADC-maps were done using the auto function in NIC. The co-registration between the T1 images and the patient dose plans were done using the auto function in the treatment planning system Eclipse from Varian. Regions of interest were drawn on the T1-weighted images in NIC based on iso curves from Eclipse. Data was analysed by t-test. Estimates are given with 95 % CI. Results: A mean ADC difference of 4.6(0.3;8.9) X 10{sup -5} mm{sup 2}/s, p = 0.03 was found between paired white matter structures with a mean dose difference of 31.4 Gy. Comparing the ADC-values of the areas with highest dose from the paired data (dose > 33 Gy) with normal white matter (dose < 5 Gy) resulted in a mean dose difference of 44.1 Gy and a mean ADC difference of 7.87(3.15;12.60) X 10{sup -5} mm{sup 2}/s, p = 0.003. Following results were obtained when looking at differences between white matter mean ADC in average dose levels from 5 to 55 Gy in steps of 10 Gy with normal white matter mean ADC: 5 Gy; 1.91(-1.76;5.58) X 10{sup -5} mm{sup 2}/s, p = 0.29; 15 Gy; 5.81(1.53;10.11) X 10{sup -5} mm{sup 2}/s, p = 0.01; 25 Gy; 5.80(2.43;9.18) X 10{sup -5} mm{sup 2}/s, p = 0.002; 35 Gy; 5.93(2.89;8.97) X 10

  20. Exploratory analysis of diffusion tensor imaging in children with attention deficit hyperactivity disorder: evidence of abnormal white matter structure.

    Science.gov (United States)

    Pastura, Giuseppe; Doering, Thomas; Gasparetto, Emerson Leandro; Mattos, Paulo; Araújo, Alexandra Prüfer

    2016-06-01

    Abnormalities in the white matter microstructure of the attentional system have been implicated in the aetiology of attention deficit hyperactivity disorder (ADHD). Diffusion tensor imaging (DTI) is a promising magnetic resonance imaging (MRI) technology that has increasingly been used in studies of white matter microstructure in the brain. The main objective of this work was to perform an exploratory analysis of white matter tracts in a sample of children with ADHD versus typically developing children (TDC). For this purpose, 13 drug-naive children with ADHD of both genders underwent MRI using DTI acquisition methodology and tract-based spatial statistics. The results were compared to those of a sample of 14 age- and gender-matched TDC. Lower fractional anisotropy was observed in the splenium of the corpus callosum, right superior longitudinal fasciculus, bilateral retrolenticular part of the internal capsule, bilateral inferior fronto-occipital fasciculus, left external capsule and posterior thalamic radiation (including right optic radiation). We conclude that white matter tracts in attentional and motor control systems exhibited signs of abnormal microstructure in this sample of drug-naive children with ADHD.

  1. Mathematical methods for diffusion MRI processing

    International Nuclear Information System (INIS)

    Lenglet, C.; Lenglet, C.; Sapiro, G.; Campbell, J.S.W.; Pike, G.B.; Campbell, J.S.W.; Siddiqi, K.; Descoteaux, M.; Haro, G.; Wassermann, D.; Deriche, R.; Wassermann, D.; Anwander, A.; Thompson, P.M.

    2009-01-01

    In this article, we review recent mathematical models and computational methods for the processing of diffusion Magnetic Resonance Images, including state-of-the-art reconstruction of diffusion models, cerebral white matter connectivity analysis, and segmentation techniques. We focus on Diffusion Tensor Images (DTI) and Q-Ball Images (QBI). (authors)

  2. Diffusion-weighted MR imaging of the pancreas: optimizing b-value for visualization of pancreatic adenocarcinoma

    International Nuclear Information System (INIS)

    Fukukura, Yoshihiko; Shindo, Toshikazu; Hakamada, Hiroto; Takumi, Koji; Umanodan, Tomokazu; Nakajo, Masanori; Kamimura, Kiyoshisa; Umanodan, Aya; Ideue, Junnichi; Yoshiura, Takashi

    2016-01-01

    To determine the optimal b-value of 3.0-T diffusion-weighted imaging (DWI) for visualizing pancreatic adenocarcinomas Fifty-five patients with histologically confirmed pancreatic adenocarcinoma underwent DWI with different b-values (b = 500, 1000, 1500, and 2000 s/mm"2) at 3.0 T. For each b-value, we retrospectively evaluated DWI findings of pancreatic adenocarcinomas (clear hyperintensity relative to the surrounding pancreas, hyperintensity with an unclear distal border, and isointensity) and image quality, and measured tumour-to-pancreas signal intensity (SI) ratios. DWI findings, image quality, and tumour-to-pancreas SI ratios were compared between the four b-values. There was a significantly higher incidence of tumours showing clear hyperintensity on DWI with b-value of 1500 s/mm"2 than on that with b-value of 1000 s/mm"2 (P < 0.001), and on DWI with b-value of 1000 s/mm"2 than on that with b-value of 500 s/mm"2 (P < 0.001). The tumour-to-distal pancreas SI ratio was higher with b-value of 1500 s/mm"2 than with b-value of 1000 s/mm"2 (P < 0.001), and with b-value of 1000 s/mm"2 than with b-value of 500 s/mm"2 (P < 0.001). A lower image quality was obtained at increasing b-values (P < 0.001); the lowest scores were observed with b-value of 2000 s/mm"2. The use of b = 1500 s/mm"2 for 3.0-T DWI can improve the delineation of pancreatic adenocarcinomas. (orig.)

  3. MR imaging identification of white-matter lesions in uncomplicated chronic alcoholism

    International Nuclear Information System (INIS)

    Gallucci, M.; Amicarelli, I.; DiCesare, E.; Rossi, A.; Stratta, P.; Casacchia, M.; Passariello, R.

    1987-01-01

    Chronic alcoholics may have central nervous system (CNS) lesions, such as microvasculitis, or glial, neural, and myelinic degeneration, as has been documented in postmortem studies on patients with Wernicke disease, corpus callosum degeneration, or central pontine myelinolisis. The presence of early white matter diseases can aslo be projected in patients not suffering the neurologic complications of alcoholism. Thirty-five alcoholics (DSM-III criteria) and 35 healthy controls underwent MR imaging at 0.5 T (repetition time/echo time = 1,800/30-120 msec). Subjects older than 60 years or who had CNS injuries or clinically evident hepatopathies were excluded. Besides the aspecific corticosubcortical and cerebellar atrophy, MR imaging disclosed multiple round hyperintense areas in the white matter of 14 patients but in none of the healthy controls. These results suggest early involvement of the brain in chronic alcoholism

  4. Diffuse periventricular leukomalacia in preterm children: assessment of grey matter changes by MRI

    International Nuclear Information System (INIS)

    Tzarouchi, L.C.; Xydis, V.; Zikou, A.K.; Papastefanaki, M.; Argyropoulou, Maria I.; Drougia, A.; Andronikou, S.; Astrakas, L.G.

    2011-01-01

    Preterm children may have cognitive deficits and behavioural disorders suggestive of grey matter (GM) injury. The prevalence is higher in preterm children with diffuse periventricular leukomalacia (dPVL). Evaluate changes in the volume of 116 GM areas in preterm children with dPVL. Eleven preterm children with dPVL, gestational age 32.8 ± 2.6 weeks, examined at corrected age 22.0 ± 18.2 months and 33 matched preterm controls with normal brain MRI were studied. Volumes of 116 individual GM areas, and white matter/cerebrospinal fluid (WM/CSF) ratio were calculated on T1-weighted high-resolution images after segmentation. Relative to controls, children with dPVL had decreased GM volume of the hippocampus, amygdala, and frontal lobes and temporal middle gyrus (P < 0.05); increased GM volume of the putamen, thalamus, globus pallidum, superior temporal gyrus and of the parietal and occipital lobes (P < 0.05) and lower WM volume/higher CSF volume (P < 0.05). WM/CSF ratios also differed (P < 0.05). Preterm children with dPVL have increased regional GM volume in some areas probably related with a process of brain plasticity-regeneration and reduced GM volume in areas associated with cognition and memory. (orig.)

  5. Diffuse periventricular leukomalacia in preterm children: assessment of grey matter changes by MRI

    Energy Technology Data Exchange (ETDEWEB)

    Tzarouchi, L.C.; Xydis, V.; Zikou, A.K.; Papastefanaki, M.; Argyropoulou, Maria I. [University of Ioannina, Department of Radiology, Medical School, Ioannina (Greece); Drougia, A.; Andronikou, S. [University of Ioannina, Neonatal Intensive Care Unit, Child Health Department, Medical School, Ioannina (Greece); Astrakas, L.G. [University of Ioannina, Department of Medical Physics, Medical School, Ioannina (Greece)

    2011-12-15

    Preterm children may have cognitive deficits and behavioural disorders suggestive of grey matter (GM) injury. The prevalence is higher in preterm children with diffuse periventricular leukomalacia (dPVL). Evaluate changes in the volume of 116 GM areas in preterm children with dPVL. Eleven preterm children with dPVL, gestational age 32.8 {+-} 2.6 weeks, examined at corrected age 22.0 {+-} 18.2 months and 33 matched preterm controls with normal brain MRI were studied. Volumes of 116 individual GM areas, and white matter/cerebrospinal fluid (WM/CSF) ratio were calculated on T1-weighted high-resolution images after segmentation. Relative to controls, children with dPVL had decreased GM volume of the hippocampus, amygdala, and frontal lobes and temporal middle gyrus (P < 0.05); increased GM volume of the putamen, thalamus, globus pallidum, superior temporal gyrus and of the parietal and occipital lobes (P < 0.05) and lower WM volume/higher CSF volume (P < 0.05). WM/CSF ratios also differed (P < 0.05). Preterm children with dPVL have increased regional GM volume in some areas probably related with a process of brain plasticity-regeneration and reduced GM volume in areas associated with cognition and memory. (orig.)

  6. Nonlinear Diffusion and Transient Osmosis

    International Nuclear Information System (INIS)

    Igarashi, Akira; Rondoni, Lamberto; Botrugno, Antonio; Pizzi, Marco

    2011-01-01

    We investigate both analytically and numerically the concentration dynamics of a solution in two containers connected by a narrow and short channel, in which diffusion obeys a porous medium equation. We also consider the variation of the pressure in the containers due to the flow of matter in the channel. In particular, we identify a phenomenon, which depends on the transport of matter across nano-porous membranes, which we call ''transient osmosis . We find that nonlinear diffusion of the porous medium equation type allows numerous different osmotic-like phenomena, which are not present in the case of ordinary Fickian diffusion. Experimental results suggest one possible candidate for transiently osmotic processes. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  7. Review of diffusion tensor imaging and its application in children

    Energy Technology Data Exchange (ETDEWEB)

    Vorona, Gregory A. [Children' s Hospital of Richmond at Virginia Commonwealth University, Department of Radiology, Richmond, VA (United States); Berman, Jeffrey I. [Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States)

    2015-09-15

    Diffusion MRI is an imaging technique that uses the random motion of water to probe tissue microstructure. Diffusion tensor imaging (DTI) can quantitatively depict the organization and connectivity of white matter. Given the non-invasiveness of the technique, DTI has become a widely used tool for researchers and clinicians to examine the white matter of children. This review covers the basics of diffusion-weighted imaging and diffusion tensor imaging and discusses examples of their clinical application in children. (orig.)

  8. White Matter Structural Differences in Young Children With Type 1 Diabetes: A Diffusion Tensor Imaging Study

    Science.gov (United States)

    Aye, Tandy; Barnea-Goraly, Naama; Ambler, Christian; Hoang, Sherry; Schleifer, Kristin; Park, Yaena; Drobny, Jessica; Wilson, Darrell M.; Reiss, Allan L.; Buckingham, Bruce A.

    2012-01-01

    OBJECTIVE To detect clinical correlates of cognitive abilities and white matter (WM) microstructural changes using diffusion tensor imaging (DTI) in young children with type 1 diabetes. RESEARCH DESIGN AND METHODS Children, ages 3 to <10 years, with type 1 diabetes (n = 22) and age- and sex-matched healthy control subjects (n = 14) completed neurocognitive testing and DTI scans. RESULTS Compared with healthy controls, children with type 1 diabetes had lower axial diffusivity (AD) values (P = 0.046) in the temporal and parietal lobe regions. There were no significant differences between groups in fractional anisotropy and radial diffusivity (RD). Within the diabetes group, there was a significant, positive correlation between time-weighted HbA1c and RD (P = 0.028). A higher, time-weighted HbA1c value was significantly correlated with lower overall intellectual functioning measured by the full-scale intelligence quotient (P = 0.03). CONCLUSIONS Children with type 1 diabetes had significantly different WM structure (as measured by AD) when compared with controls. In addition, WM structural differences (as measured by RD) were significantly correlated with their HbA1c values. Additional studies are needed to determine if WM microstructural differences in young children with type 1 diabetes predict future neurocognitive outcome. PMID:22966090

  9. Pediatric Patients Demonstrate Progressive T1-Weighted Hyperintensity in the Dentate Nucleus following Multiple Doses of Gadolinium-Based Contrast Agent.

    Science.gov (United States)

    Roberts, D R; Chatterjee, A R; Yazdani, M; Marebwa, B; Brown, T; Collins, H; Bolles, G; Jenrette, J M; Nietert, P J; Zhu, X

    2016-12-01

    While there have been recent reports of brain retention of gadolinium following gadolinium-based contrast agent administration in adults, a retrospective series of pediatric patients has not previously been reported, to our knowledge. We investigated the relationship between the number of prior gadolinium-based contrast agent doses and increasing T1 signal in the dentate nucleus on unenhanced T1-weighted MR imaging. We hypothesized that despite differences in pediatric physiology and the smaller gadolinium-based contrast agent doses that pediatric patients are typically administered based on weighted-adjusted dosing, the pediatric brain would also demonstrate dose-dependent increasing T1 signal in the dentate nucleus. We included children with multiple gadolinium-based contrast agent administrations at our institution. A blinded reader placed ROIs within the dentate nucleus and adjacent cerebellar white matter. To eliminate reader bias, we also performed automated ROI delineation of the dentate nucleus, cerebellar white matter, and pons. Dentate-to-cerebellar white matter and dentate-to pons ratios were compared with the number of gadolinium-based contrast agent administrations. During 20 years at our institution, 280 patients received at least 5 gadolinium-based contrast agent doses, with 1 patient receiving 38 doses. Sixteen patients met the inclusion/exclusion criteria for ROI analysis. Blinded reader dentate-to-cerebellar white matter ratios were significantly associated with gadolinium-based contrast agent doses (r s = 0.77, P = .001). The dentate-to-pons ratio and dentate-to-cerebellar white matter ratios based on automated ROI placement were also significantly correlated with gadolinium-based contrast agent doses (t = 4.98, P contrast agent doses is significantly correlated with progressive T1-weighted dentate hyperintensity. Definitive confirmation of gadolinium deposition requires tissue analysis. Any potential clinical sequelae of gadolinium retention in

  10. Differential diagnostic value of diffusion weighted imaging on brain abscess and necrotic or cystic brain tumors

    International Nuclear Information System (INIS)

    Zhang Xiaoya; Yin Jie; Wang Kunpeng; Zhang Jiandang; Liang Biling

    2009-01-01

    Objective: To investigate the value of diffusion weighted imaging (DWI)on brain abscess and necrotic or cystic brain tumors. Methods: 27 cases with brain abscesses and 33 cases with necrotic or cystic brain tumors (gliomas or metastases) were performed conventional MRI and DWI. Apparent diffusion coefficient (ADC) of region of interest (ROI) was measured and statistically tested. Sensitivity and specificity were calculated and compared with conventional MR and DWI. Results: Hyperintensity signal was seen on most brain abscesses. All necrotic or cystic brain tumors showed hypointensity signal on DWI. There was statistical significance on ADC of them. The sensitivity and specificity of conventional MRI was lower than that of DWI. Conclusion: DWI and ADC were useful in distinguishing brain abscessed from necrotic or cystic brain tumors, which was important in addition to conventional MRI. (authors)

  11. Preliminary assessment of amyotrophic lateral sclerosis by using MRI and MR diffusion tensor imaging

    International Nuclear Information System (INIS)

    Ma Lin; Yin Hong; Cai Youquan; Li Dejun; Shen Dingguo

    2003-01-01

    Objective: To describe the characteristic MR findings in the brain in patients with amyotrophic lateral sclerosis (ALS), and to assess the diagnostic value of conventional MR imaging and fractional anisotropy (FA) of diffusion tensor imaging (DTI). Methods: Conventional MR imaging was performed in 14 clinically proved ALS patients and 12 age-matched normal controls. Contrast enhanced MR images were acquired in 2 patients. Axial and coronal DTI scans were performed in 10 patients and 12 normal controls with SE-EPI sequence. The b value was 1000 s/mm 2 , the number of diffusion sensitive gradient direction was 25. For quantitative assessment of the corticospinal tract (CST), FA value of bilateral CST was measured at the level of posterior limb (PL) of the internal capsule (IC) and the cerebral peduncle of the midbrain, respectively, and statistical analysis was performed. Results: Focal slight low signal intensity on T 1 WI and high signal intensity (hyperintense to gray matter) on T 2 WI was demonstrated in 6 ALS cases (42.9%) in bilateral PL of the IC, and the high signal was longitudinally continuous from the PL to the cerebral peduncle on T 2 WI coronal plane, corresponding to the course of CST. In another 8 ALS cases (57.1%), the focal slight low signal intensity on T 1 WI and slight high signal intensity (isointense to gray matter) on T 2 WI was revealed in bilateral PL of the IC. No abnormal contrast enhancement was detected in the 2 cases. In control group, the focal slight low signal intensity on T 1 WI and slight high signal intensity (isointense to gray matter) on T 2 WI was demonstrated in all 12 subjects in bilateral PL of the IC. FA values of the patient group were significantly lower than that of the control group at the level of the PL of the IC (F=7.38, P<0.01) and the cerebral peduncle (F=7.31, P=0.01), respectively. Conclusion: Clinical information must be considered when diagnosing ALS by using conventional MR imaging. The decreased FA value in

  12. Diffusion tensor imaging in children and adolescents with tuberous sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Karadag, Demet [Institute of Diagnostic and Interventional Radiology, Friedrich Schiller University, Department of Paediatric Radiology, Jena (Germany); Kirikkale Yuksek Ihtisas Hospital, Department of Radiology, Kirirkale (Turkey); Mentzel, Hans-J.; Loebel, Ulrike; Reichenbach, Juergen R.; Kaiser, Werner A. [Institute of Diagnostic and Interventional Radiology, Friedrich Schiller University, Department of Paediatric Radiology, Jena (Germany); Guellmar, Daniel [Institute of Diagnostic and Interventional Radiology, Friedrich Schiller University, Department of Paediatric Radiology, Jena (Germany); Friedrich Schiller University, Biomagnetic Centre, Clinic of Neurology, Jena (Germany); Rating, Tina; Brandl, Ulrich [Friedrich Schiller University, Department of Paediatric Neurology, Jena (Germany)

    2005-10-01

    Tuberous sclerosis (TS) is characterised by benign hamartomatous lesions in many organs. Diffusion tensor imaging (DTI) can detect microstructural changes in pathological processes. To determine apparent diffusion coefficient (ADC) and fractional anisotropy (FA) maps in children with TS and to investigate the diffusion properties in cortical tubers, white-matter lesions, perilesional white matter, and contralateral normal-appearing white matter, and to compare the results with ADC and FA maps of normal age- and sex-matched volunteers. Seven children and adolescents (age range 2-20 years) suffering from TS were included. MRI was performed on a 1.5-T scanner using a transmit/receive coil with T1-W and T2-W spin-echo and FLAIR sequences. DT images were acquired by using a single-shot echo-planar pulse sequence. Diffusion gradients were applied in six different directions with a b value of 1,000 s/mm{sup 2}. ADC was higher in cortical tubers than in the corresponding cortical location of controls. ADC values were higher and FA values were lower in white-matter lesions and perilesional white matter than in both the contralateral normal-appearing white matter of patients and in controls. There were no significant differences for both ADC and FA values in the normal-appearing white matter of patients with TS compared to controls. DTI provides important information about cortical tubers, white-matter abnormalities, and perilesional white matter in patients with TS. (orig.)

  13. Hyperintense globus pallidus on T1-weighted MR imaging in acute kernicterus: is it common or rare?

    Energy Technology Data Exchange (ETDEWEB)

    Coskun, Abdulhakim; Yikilmaz, Ali; Karahan, Okkes Ibrahim; Manav, Ali [Erciyes University Medical School, Department of Radiology, Kayseri (Turkey); Kumandas, Sefer [Erciyes University Medical School, Department of Neuropediatry, Kayseri (Turkey); Akcakus, Mustafa [Erciyes University Medical School, Department of Neonatalogy, Kayseri (Turkey)

    2005-06-01

    Globus pallidus involvement is a well-known magnetic resonance (MR) imaging finding of acute kernicterus. However, it is not clear how early the involvement of globus pallidus occurs and whether or not it is seen in every case. Therefore, we aimed to investigate the globus pallidus involvement in 13 neonates with acute kernicterus by MR imaging. Thirteen neonates who were admitted with jaundice, encephalopathy and indirect hyperbilirubinemia (mean, 37.0 mg/dl) were prospectively evaluated with cranial MR imaging. Pathological signal changes were noted concerning the globus pallidus. Eight of the 13 patients demonstrated bilateral, symmetric increased signal intensity in the globus pallidus on T1-weighted MR imaging. These lesions were not apparent on T2-weighted images. Multiple parenchymal punctuate T1 hyperintense lesions were detected in one patient without globus pallidus involvement. This appearance was consistent with hemorrhage. The MR imaging findings of the other four patients showed no evidence of abnormality. The symmetric involvement of globus pallidus seen as hyperintense on T1-weighted MR imaging is a common and characteristic finding of acute kernicterus. (orig.)

  14. Hyperintense globus pallidus on T1-weighted MR imaging in acute kernicterus: is it common or rare?

    International Nuclear Information System (INIS)

    Coskun, Abdulhakim; Yikilmaz, Ali; Karahan, Okkes Ibrahim; Manav, Ali; Kumandas, Sefer; Akcakus, Mustafa

    2005-01-01

    Globus pallidus involvement is a well-known magnetic resonance (MR) imaging finding of acute kernicterus. However, it is not clear how early the involvement of globus pallidus occurs and whether or not it is seen in every case. Therefore, we aimed to investigate the globus pallidus involvement in 13 neonates with acute kernicterus by MR imaging. Thirteen neonates who were admitted with jaundice, encephalopathy and indirect hyperbilirubinemia (mean, 37.0 mg/dl) were prospectively evaluated with cranial MR imaging. Pathological signal changes were noted concerning the globus pallidus. Eight of the 13 patients demonstrated bilateral, symmetric increased signal intensity in the globus pallidus on T1-weighted MR imaging. These lesions were not apparent on T2-weighted images. Multiple parenchymal punctuate T1 hyperintense lesions were detected in one patient without globus pallidus involvement. This appearance was consistent with hemorrhage. The MR imaging findings of the other four patients showed no evidence of abnormality. The symmetric involvement of globus pallidus seen as hyperintense on T1-weighted MR imaging is a common and characteristic finding of acute kernicterus. (orig.)

  15. Child dermoid cyst mimicking a craniopharyngioma: the benefit of MRI T2-weighted diffusion sequence.

    Science.gov (United States)

    Amelot, Aymeric; Borha, Alin; Calmon, Raphael; Barbet, Patrick; Puget, Stephanie

    2018-02-01

    Brain dermoid cysts are very rare lesions. Although benign, these cysts may be associated with devastating complications due to mass effect or meningitis. The discovery of completely asymptomatic dermoid cysts in the pediatric population is exceedingly rare. Despite the advances in imaging modalities, it sometimes remains difficult to exclude the differential diagnosis of craniopharyngioma. We describe a 12-year-old boy addressed for suspicion of craniopharyngioma diagnosed by decreased visual acuity, bitemporal hemianopia and a CT scan showing a large hypodense suprasellar lesion with intralesional calcifications. Despite the unusual localization and size of this lesion, the absence of dermal sinus commonly found, and before visualizing a hyperintense mass on MRI-diffusion, the diagnosis of craniopharyngioma was ruled out in favor of a dermoid cyst. Radical excision was performed. In the suprasellar area, craniopharyngioma and dermoid cyst may have very similar radiological aspects: low density masses on CT scan and a hyperintense signal on T1-weighted MRI sequences with a variable signal on T2-weighted sequences. Hitherto, only two cases in literature have described suprasellar dermoid cyst. Their initial diagnosis was facilitated by the presence of a dermal sinus.

  16. Major Superficial White Matter Abnormalities in Huntington's Disease

    Science.gov (United States)

    Phillips, Owen R.; Joshi, Shantanu H.; Squitieri, Ferdinando; Sanchez-Castaneda, Cristina; Narr, Katherine; Shattuck, David W.; Caltagirone, Carlo; Sabatini, Umberto; Di Paola, Margherita

    2016-01-01

    Background: The late myelinating superficial white matter at the juncture of the cortical gray and white matter comprising the intracortical myelin and short-range association fibers has not received attention in Huntington's disease. It is an area of the brain that is late myelinating and is sensitive to both normal aging and neurodegenerative disease effects. Therefore, it may be sensitive to Huntington's disease processes. Methods: Structural MRI data from 25 Pre-symptomatic subjects, 24 Huntington's disease patients and 49 healthy controls was run through a cortical pattern-matching program. The surface corresponding to the white matter directly below the cortical gray matter was then extracted. Individual subject's Diffusion Tensor Imaging (DTI) data was aligned to their structural MRI data. Diffusivity values along the white matter surface were then sampled at each vertex point. DTI measures with high spatial resolution across the superficial white matter surface were then analyzed with the General Linear Model to test for the effects of disease. Results: There was an overall increase in the axial and radial diffusivity across much of the superficial white matter (p < 0.001) in Pre-symptomatic subjects compared to controls. In Huntington's disease patients increased diffusivity covered essentially the whole brain (p < 0.001). Changes are correlated with genotype (CAG repeat number) and disease burden (p < 0.001). Conclusions: This study showed broad abnormalities in superficial white matter even before symptoms are present in Huntington's disease. Since, the superficial white matter has a unique microstructure and function these abnormalities suggest it plays an important role in the disease. PMID:27242403

  17. A calculation of baryon diffusion constant in hot and dense hadronic matter based on an event generator URASiMA

    International Nuclear Information System (INIS)

    Sasaki, N.; Miyamura, O.; Nonaka, C.; Muroya, S.

    2000-01-01

    We evaluate thermodynamical quantities and transport coefficient of a dense and hot hadronic matter based on an event generator URASiMA (Ultra-Relativistic AA collision Simulator based on Multiple Scattering Algorithm). The statistical ensembles in equilibrium with fixed temperature and chemical potential are generated by imposing periodic boundary condition to the simulation of URASiMA, where energy density and baryon number density is conserved. Achievement of the thermal equilibrium and the chemical equilibrium are confirmed by the common value of slope parameter in the energy distributions and the saturation of the numbers of contained particles, respectively. By using the generated ensembles, we investigate the temperature dependence and the chemical potential dependence of the baryon diffusion constant of a dense and hot hadronic matter. (author)

  18. EXTRAGALACTIC DARK MATTER AND DIRECT DETECTION EXPERIMENTS

    International Nuclear Information System (INIS)

    Baushev, A. N.

    2013-01-01

    Recent astronomical data strongly suggest that a significant part of the dark matter content of the Local Group and Virgo Supercluster is not incorporated into the galaxy halos and forms diffuse components of these galaxy clusters. A portion of the particles from these components may penetrate the Milky Way and make an extragalactic contribution to the total dark matter containment of our Galaxy. We find that the particles of the diffuse component of the Local Group are apt to contribute ∼12% to the total dark matter density near Earth. The particles of the extragalactic dark matter stand out because of their high speed (∼600 km s –1 ), i.e., they are much faster than the galactic dark matter. In addition, their speed distribution is very narrow (∼20 km s –1 ). The particles have an isotropic velocity distribution (perhaps, in contrast to the galactic dark matter). The extragalactic dark matter should provide a significant contribution to the direct detection signal. If the detector is sensitive only to the fast particles (v > 450 km s –1 ), then the signal may even dominate. The density of other possible types of the extragalactic dark matter (for instance, of the diffuse component of the Virgo Supercluster) should be relatively small and comparable with the average dark matter density of the universe. However, these particles can generate anomaly high-energy collisions in direct dark matter detectors.

  19. White matter biomarkers from diffusion MRI

    DEFF Research Database (Denmark)

    Jespersen, Sune

    2018-01-01

    Abstract As part of an issue celebrating 2 decades of Joseph Ackerman editing the Journal of Magnetic Resonance, this paper reviews recent progress in one of the many areas in which Ackerman and his lab has made significant contributions: NMR measurement of diffusion in biological media, specific...

  20. Spin-diffusions and diffusive molecular dynamics

    Science.gov (United States)

    Farmer, Brittan; Luskin, Mitchell; Plecháč, Petr; Simpson, Gideon

    2017-12-01

    Metastable configurations in condensed matter typically fluctuate about local energy minima at the femtosecond time scale before transitioning between local minima after nanoseconds or microseconds. This vast scale separation limits the applicability of classical molecular dynamics (MD) methods and has spurned the development of a host of approximate algorithms. One recently proposed method is diffusive MD which aims at integrating a system of ordinary differential equations describing the likelihood of occupancy by one of two species, in the case of a binary alloy, while quasistatically evolving the locations of the atoms. While diffusive MD has shown itself to be efficient and provide agreement with observations, it is fundamentally a model, with unclear connections to classical MD. In this work, we formulate a spin-diffusion stochastic process and show how it can be connected to diffusive MD. The spin-diffusion model couples a classical overdamped Langevin equation to a kinetic Monte Carlo model for exchange amongst the species of a binary alloy. Under suitable assumptions and approximations, spin-diffusion can be shown to lead to diffusive MD type models. The key assumptions and approximations include a well-defined time scale separation, a choice of spin-exchange rates, a low temperature approximation, and a mean field type approximation. We derive several models from different assumptions and show their relationship to diffusive MD. Differences and similarities amongst the models are explored in a simple test problem.

  1. Relapsing Remitting Multiple Sclerosis in X-Linked Charcot-Marie-Tooth Disease with Central Nervous System Involvement

    OpenAIRE

    Koutsis, Georgios; Karadima, Georgia; Floroskoufi, Paraskewi; Raftopoulou, Maria; Panas, Marios

    2015-01-01

    We report a patient with relapsing remitting multiple sclerosis (MS) and X-linked Charcot-Marie-Tooth disease (CMTX), carrying a GJB1 mutation affecting connexin-32 (c.191G>A, p. Cys64Tyr) which was recently reported by our group. This is the third case report of a patient with CMTX developing MS, but it is unique in the fact that other family members carrying the same mutation were found to have asymptomatic central nervous system (CNS) involvement (diffuse white matter hyperintensity on bra...

  2. Brain MRI findings of carbon disulfide poisoning

    International Nuclear Information System (INIS)

    Cha, Joo Hee; Kim, Mi Jung; Yim, Sang Hyuk; Kim, Sam Soo; Han, Heon; Kim, Rok Ho

    2002-01-01

    To evaluate the findings of brain MRI in patients with carbon disulfide poisoning. Ninety-one patients who had suffered carbon disulfide poisoning [male:female=87:4; age, 32-74 (mean 53.3) years] were included in this study. To determine the extent of white matter hyperintensity (Grade 0-V) and lacunar infarction, T2-weighted MR imaging of the brain was performed. T2-weighted images depicted white matter hyperintensity in 70 patients (76.9%) and lacunar infarcts in 27 (29.7%). In these patients, the prevalent findings at T2-weighted MR imaging of the brain were white matter hyperintensity and lacunar infarcts. Disturbance of the cardiovascular system by carbon disulfide might account for these results

  3. Correlation between white matter damage and gray matter lesions in multiple sclerosis patients

    Directory of Open Access Journals (Sweden)

    Xue-mei Han

    2017-01-01

    Full Text Available We observed the characteristics of white matter fibers and gray matter in multiple sclerosis patients, to identify changes in diffusion tensor imaging fractional anisotropy values following white matter fiber injury. We analyzed the correlation between fractional anisotropy values and changes in whole-brain gray matter volume. The participants included 20 patients with relapsing-remitting multiple sclerosis and 20 healthy volunteers as controls. All subjects underwent head magnetic resonance imaging and diffusion tensor imaging. Our results revealed that fractional anisotropy values decreased and gray matter volumes were reduced in the genu and splenium of corpus callosum, left anterior thalamic radiation, hippocampus, uncinate fasciculus, right corticospinal tract, bilateral cingulate gyri, and inferior longitudinal fasciculus in multiple sclerosis patients. Gray matter volumes were significantly different between the two groups in the right frontal lobe (superior frontal, middle frontal, precentral, and orbital gyri, right parietal lobe (postcentral and inferior parietal gyri, right temporal lobe (caudate nucleus, right occipital lobe (middle occipital gyrus, right insula, right parahippocampal gyrus, and left cingulate gyrus. The voxel sizes of atrophic gray matter positively correlated with fractional anisotropy values in white matter association fibers in the patient group. These findings suggest that white matter fiber bundles are extensively injured in multiple sclerosis patients. The main areas of gray matter atrophy in multiple sclerosis are the frontal lobe, parietal lobe, caudate nucleus, parahippocampal gyrus, and cingulate gyrus. Gray matter atrophy is strongly associated with white matter injury in multiple sclerosis patients, particularly with injury to association fibers.

  4. Interacting hot dark matter

    International Nuclear Information System (INIS)

    Atrio-Barandela, F.; Davidson, S.

    1997-01-01

    We discuss the viability of a light particle (∼30eV neutrino) with strong self-interactions as a dark matter candidate. The interaction prevents the neutrinos from free-streaming during the radiation-dominated regime so galaxy-sized density perturbations can survive. Smaller scale perturbations are damped due to neutrino diffusion. We calculate the power spectrum in the imperfect fluid approximation, and show that it is damped at the length scale one would estimate due to neutrino diffusion. The strength of the neutrino-neutrino coupling is only weakly constrained by observations, and could be chosen by fitting the power spectrum to the observed amplitude of matter density perturbations. The main shortcoming of our model is that interacting neutrinos cannot provide the dark matter in dwarf galaxies. copyright 1997 The American Physical Society

  5. Cigarette smoking is associated with reduced microstructural integrity of cerebral white matter.

    Science.gov (United States)

    Gons, Rob A R; van Norden, Anouk G W; de Laat, Karlijn F; van Oudheusden, Lucas J B; van Uden, Inge W M; Zwiers, Marcel P; Norris, David G; de Leeuw, Frank-Erik

    2011-07-01

    Cigarette smoking doubles the risk of dementia and Alzheimer's disease. Various pathophysiological pathways have been proposed to cause such a cognitive decline, but the exact mechanisms remain unclear. Smoking may affect the microstructural integrity of cerebral white matter. Diffusion tensor imaging is known to be sensitive for microstructural changes in cerebral white matter. We therefore cross-sectionally studied the relation between smoking behaviour (never, former, current) and diffusion tensor imaging parameters in both normal-appearing white matter and white matter lesions as well as the relation between smoking behaviour and cognitive performance. A structured questionnaire was used to ascertain the amount and duration of smoking in 503 subjects with small-vessel disease, aged between 50 and 85 years. Cognitive function was assessed with a neuropsychological test battery. All subjects underwent 1.5 Tesla magnetic resonance imaging. Using diffusion tensor imaging, fractional anisotropy and mean diffusivity were calculated in both normal-appearing white matter and white matter lesions. A history of smoking was associated with significant higher values of mean diffusivity in normal-appearing white matter and white matter lesions (P-trend for smoking status = 0.02) and with poorer cognitive functioning compared with those who never smoked. Associations with smoking and loss of structural integrity appeared to be strongest in normal-appearing white matter. Furthermore, the duration of smoking cessation was positively related to lower values of mean diffusivity and higher values of fractional anisotropy in normal-appearing white matter [β = -0.004 (95% confidence interval -0.007 to 0.000; P = 0.03) and β = 0.019 (95% confidence interval 0.001-0.038; P = 0.04)]. Fractional anisotropy and mean diffusivity values in normal-appearing white matter of subjects who had quit smoking for >20 years were comparable with subjects who had never smoked. These data suggest

  6. Linear signal hyperintensity adjacent to the subchondral bone plate at the knee on T2-weighted fat-saturated sequences: imaging aspects and association with structural lesions

    Energy Technology Data Exchange (ETDEWEB)

    Gondim Teixeira, Pedro Augusto; Balaj, Clemence [CHU Hopital Central, Service D' Imagerie Guilloz, Nancy (France); Universite de Lorraine, IADI, UMR S 947, Nancy (France); Marie, Beatrice [CHU Hopital Central, Service d' Anatomo-Pathologie, Nancy (France); Lecocq, Sophie; Louis, Matthias; Blum, Alain [CHU Hopital Central, Service D' Imagerie Guilloz, Nancy (France); Braun, Marc [CHU Hopital Central, Service de Neuroradiologie, Nancy (France)

    2014-11-15

    To describe the association between linear T2 signal abnormalities in the subchondral bone and structural knee lesions. MR studies of patients referred for the evaluation of knee pain were retrospectively evaluated and 133 of these patients presented bone marrow edema pattern (BMEP) (study group) and while 61 did not (control group). The presence of linear anomalies of the subchondral bone on T2-weighted fat-saturated sequences was evaluated. The findings were correlated to the presence of structural knee lesions and to the duration of the patient's symptoms. Histologic analysis of a cadaveric specimen was used for anatomic correlation. Linear T2 hyperintensities at the subchondral bone were present in 41 % of patients with BMEP. None of the patients in the control group presented this sign. When a subchondral linear hyperintensity was present, the prevalence of radial or root tears was high and that of horizontal tears was low (71.4 and 4.8 %, respectively). Sixty-nine percent of the patients with a subchondral insufficiency fracture presented a subchondral linear hyperintensity. It was significantly more prevalent in patients with acute or sub-acute symptoms (p < 0.0001). The studied linear T2 hyperintensity is located at the subchondral spongiosa and can be secondary to local or distant joint injuries. Its presence should evoke acute and sub-acute knee injuries. This sign is closely related to subchondral insufficiency fractures and meniscal tears with a compromise in meniscal function. (orig.)

  7. Diffusion-weighted MR imaging of the pancreas: optimizing b-value for visualization of pancreatic adenocarcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Fukukura, Yoshihiko; Shindo, Toshikazu; Hakamada, Hiroto; Takumi, Koji; Umanodan, Tomokazu; Nakajo, Masanori; Kamimura, Kiyoshisa; Umanodan, Aya; Ideue, Junnichi; Yoshiura, Takashi [Kagoshima University Graduate School of Medical and Dental Sciences, Department of Radiology, Kagoshima City (Japan)

    2016-10-15

    To determine the optimal b-value of 3.0-T diffusion-weighted imaging (DWI) for visualizing pancreatic adenocarcinomas Fifty-five patients with histologically confirmed pancreatic adenocarcinoma underwent DWI with different b-values (b = 500, 1000, 1500, and 2000 s/mm{sup 2}) at 3.0 T. For each b-value, we retrospectively evaluated DWI findings of pancreatic adenocarcinomas (clear hyperintensity relative to the surrounding pancreas, hyperintensity with an unclear distal border, and isointensity) and image quality, and measured tumour-to-pancreas signal intensity (SI) ratios. DWI findings, image quality, and tumour-to-pancreas SI ratios were compared between the four b-values. There was a significantly higher incidence of tumours showing clear hyperintensity on DWI with b-value of 1500 s/mm{sup 2} than on that with b-value of 1000 s/mm{sup 2} (P < 0.001), and on DWI with b-value of 1000 s/mm{sup 2} than on that with b-value of 500 s/mm{sup 2} (P < 0.001). The tumour-to-distal pancreas SI ratio was higher with b-value of 1500 s/mm{sup 2} than with b-value of 1000 s/mm{sup 2} (P < 0.001), and with b-value of 1000 s/mm{sup 2} than with b-value of 500 s/mm{sup 2} (P < 0.001). A lower image quality was obtained at increasing b-values (P < 0.001); the lowest scores were observed with b-value of 2000 s/mm{sup 2}. The use of b = 1500 s/mm{sup 2} for 3.0-T DWI can improve the delineation of pancreatic adenocarcinomas. (orig.)

  8. WMAP haze: Directly observing dark matter?

    International Nuclear Information System (INIS)

    Forbes, Michael McNeil; Zhitnitsky, Ariel R.

    2008-01-01

    In this paper, we show that dark matter in the form of dense matter/antimatter nuggets could provide a natural and unified explanation for several distinct bands of diffuse radiation from the core of the Galaxy spanning over 13 orders of magnitude in frequency. We fix all of the phenomenological properties of this model by matching to x-ray observations in the keV band, and then calculate the unambiguously predicted thermal emission in the microwave band, at frequencies smaller by 11 orders of magnitude. Remarkably, the intensity and spectrum of the emitted thermal radiation are consistent with - and could entirely explain - the so-called 'WMAP haze': a diffuse microwave excess observed from the core of our Galaxy by the Wilkinson Microwave Anisotropy Probe (WMAP). This provides another strong constraint of our proposal, and a remarkable nontrivial validation. If correct, our proposal identifies the nature of the dark matter, explains baryogenesis, and provides a means to directly probe the matter distribution in our Galaxy by analyzing several different types of diffuse emissions.

  9. Changes in Parahippocampal White Matter Integrity in Amnestic Mild Cognitive Impairment: A Diffusion Tensor Imaging Study

    Directory of Open Access Journals (Sweden)

    E. J. Rogalski

    2009-01-01

    Full Text Available In the present study, changes in the parahippocampal white matter (PWM, in the region that includes the perforant path, were investigated, in vivo, in 14 individuals with amnestic mild cognitive impairment (aMCI compared to 14 elderly controls with no cognitive impairment (NCI. For this purpose, (1 volumetry; (2 diffusion tensor imaging (DTI derived measures of mean diffusivity (MD and fractional anisotropy (FA; and (3 tractography were used. In addition, regression models were utilized to examine the association of PWM measurements with memory decline. The results from this study confirm previous findings in our laboratory and others, showing that compared to controls, individuals with aMCI have PWM volume loss. In addition to volume reduction, participants with aMCI demonstrated a significant increase in MD, but no difference in FA, both in the PWM region and in fibers modeled to pass through the PWM region. Further, the DTI metric of MD was associated with declarative memory performance, suggesting it may be a sensitive marker for memory dysfunction. These results indicate that there is general tissue loss and degradation (decreased volume; increased MD in individuals with aMCI compared to older people with normal cognitive function. However, the microstructural organization of remaining fibers, as determined by measures of anisotropic diffusion, is not significantly different from that of controls.

  10. Diffusion-weighted MR of the brain: methodology and clinical applications

    International Nuclear Information System (INIS)

    Mascalchi, Mario; Filippi, Massimo; Floris, Roberto; Fonda, Claudio; Gasparotti, Roberto; Villari, Natale

    2005-01-01

    Clinical diffusion magnetic resonance (MR) imaging in humans started in the last decade with the demonstration of the capabilities of this technique of depicting the anatomy of the white matter fibre tracts in the brain. Two main approaches in terms of reconstruction and evaluation of the images obtained with application of diffusion sensitising gradients to an echo planar imaging sequence are possible. The first approach consists of reconstruction of images in which the effect of white matter anisotropy is averaged -know as the isotropic or diffusion weighted images, which are usually evaluated subjectively for possible areas of increased or decreased signal, reflecting restricted and facilitated diffusion, respectively. The second approach implies reconstruction of image maps of the apparent diffusion coefficient (ADC), in which the T2 weighting of the echo planar diffusion sequence is cancelled out, and their objective, i.e. numerical, evaluation with regions of interest or histogram analysis. This second approach enables a quantitative and reproducible assessment of the diffusion changes mot only in areas exhibiting signal abnormality in conventional MR images, but also in areas of normal signal. A further level of image post-processing requires the acquisition of images after application of sensitive gradients along at least 6 different spatial orientations and consists of computation of the diffusion tensor and reconstruction of maps of the mean diffusivity (D) and of the white matter anisotropic properties, usually in terms of fractional anisotropy (FA). Diffusion-weighted imaging is complementary to conventional MR imaging in the evaluation of the acute ischaemic stroke. The combination of diffusion and perfusion MR imaging has the potential of providing all the information necessary for the diagnosis and management of the individual patient with acute ischaemic stroke. Diffusion-weighted MR, in particular quantitative evaluation based on the diffusion

  11. Mechanisms of cognitive impairment in cerebral small vessel disease: multimodal MRI results from the St George's cognition and neuroimaging in stroke (SCANS study.

    Directory of Open Access Journals (Sweden)

    Andrew J Lawrence

    Full Text Available Cerebral small vessel disease (SVD is a common cause of vascular cognitive impairment. A number of disease features can be assessed on MRI including lacunar infarcts, T2 lesion volume, brain atrophy, and cerebral microbleeds. In addition, diffusion tensor imaging (DTI is sensitive to disruption of white matter ultrastructure, and recently it has been suggested that additional information on the pattern of damage may be obtained from axial diffusivity, a proposed marker of axonal damage, and radial diffusivity, an indicator of demyelination. We determined the contribution of these whole brain MRI markers to cognitive impairment in SVD. Consecutive patients with lacunar stroke and confluent leukoaraiosis were recruited into the ongoing SCANS study of cognitive impairment in SVD (n = 115, and underwent neuropsychological assessment and multimodal MRI. SVD subjects displayed poor performance on tests of executive function and processing speed. In the SVD group brain volume was lower, white matter hyperintensity volume higher and all diffusion characteristics differed significantly from control subjects (n = 50. On multi-predictor analysis independent predictors of executive function in SVD were lacunar infarct count and diffusivity of normal appearing white matter on DTI. Independent predictors of processing speed were lacunar infarct count and brain atrophy. Radial diffusivity was a stronger DTI predictor than axial diffusivity, suggesting ischaemic demyelination, seen neuropathologically in SVD, may be an important predictor of cognitive impairment in SVD. Our study provides information on the mechanism of cognitive impairment in SVD.

  12. Infantile encephalitic beriberi: magnetic resonance imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Wani, Nisar A. [Government Medical College Srinagar, Department of Pediatric Radiology, Jammu and Kashmir, Pin (India); Qureshi, Umar A.; Ahmad, Kaiser; Ahmad, Waseem [Government Medical College Srinagar, Department of Pediatrics, Jammu and Kashmir (India); Jehangir, Majid [Government Medical College Srinagar, Department of Radiology, Jammu and Kashmir (India)

    2016-01-15

    Thiamine deficiency in infants is still encountered in developing countries. It may present with acute neurological manifestations of infantile encephalitic beriberi. To review brain MRI findings in infantile encephalitic beriberi from a single institution. A retrospective review of MRI scans in 22 infants with acute-onset beriberi encephalopathy was carried out. Hyperintense lesions on T2-weighted images were seen symmetrically in the putamen in all patients, in the caudate nuclei in 16/22 (73%), the thalami in 7/22 (32%) and the globi pallidi in 3/22 (14%) of the infants. Altered signal intensity lesions in the cerebral cortex were seen in 7/22 (32%). The mammillary bodies were seen in one infant and the periaqueductal gray matter in two. There was restricted diffusion in 14/22 (64%), and 6/8 children with no evidence of restriction had been imaged ≥10 days after presentation. MR spectroscopy showed increased lactate peak in 6/8 infants (75%). Recognition of symmetrical T2-W hyperintense lesions in the basal ganglia with restricted diffusion and prominent lactate peak may allow early diagnosis of encephalitic beriberi in at-risk infants. (orig.)

  13. Diffusion tensor imaging identifies deficits in white matter microstructure in subjects with type 1 diabetes that correlate with reduced neurocognitive function.

    Science.gov (United States)

    Kodl, Christopher T; Franc, Daniel T; Rao, Jyothi P; Anderson, Fiona S; Thomas, William; Mueller, Bryon A; Lim, Kelvin O; Seaquist, Elizabeth R

    2008-11-01

    Long-standing type 1 diabetes is associated with deficits on neurocognitive testing that suggest central white matter dysfunction. This study investigated whether diffusion tensor imaging (DTI), a type of magnetic resonance imaging that measures white matter integrity quantitatively, could identify white matter microstructural deficits in patients with long-standing type 1 diabetes and whether these differences would be associated with deficits found by neurocognitive tests. Twenty-five subjects with type 1 diabetes for at least 15 years and 25 age- and sex-matched control subjects completed DTI on a 3.0 Tesla scanner and a battery of neurocognitive tests. Fractional anisotropy was calculated for the major white matter tracts of the brain. Diabetic subjects had significantly lower mean fractional anisotropy than control subjects in the posterior corona radiata and the optic radiation (P < 0.002). In type 1 diabetic subjects, reduced fractional anisotropy correlated with poorer performance on the copy portion of the Rey-Osterreith Complex Figure Drawing Test and the Grooved Peg Board Test, both of which are believed to assess white matter function. Reduced fractional anisotropy also correlated with duration of diabetes and increased A1C. A history of severe hypoglycemia did not correlate with fractional anisotropy. DTI can detect white matter microstructural deficits in subjects with long-standing type 1 diabetes. These deficits correlate with poorer performance on selected neurocognitive tests of white matter function.

  14. Ischemic lesion volume determination on diffusion weighted images vs. apparent diffusion coefficient maps.

    Science.gov (United States)

    Bråtane, Bernt Tore; Bastan, Birgul; Fisher, Marc; Bouley, James; Henninger, Nils

    2009-07-07

    Though diffusion weighted imaging (DWI) is frequently used for identifying the ischemic lesion in focal cerebral ischemia, the understanding of spatiotemporal evolution patterns observed with different analysis methods remains imprecise. DWI and calculated apparent diffusion coefficient (ADC) maps were serially obtained in rat stroke models (MCAO): permanent, 90 min, and 180 min temporary MCAO. Lesion volumes were analyzed in a blinded and randomized manner by 2 investigators using (i) a previously validated ADC threshold, (ii) visual determination of hypointense regions on ADC maps, and (iii) visual determination of hyperintense regions on DWI. Lesion volumes were correlated with 24 hour 2,3,5-triphenyltetrazoliumchloride (TTC)-derived infarct volumes. TTC-derived infarct volumes were not significantly different from the ADC and DWI-derived lesion volumes at the last imaging time points except for significantly smaller DWI lesions in the pMCAO model (p=0.02). Volumetric calculation based on TTC-derived infarct also correlated significantly stronger to volumetric calculation based on last imaging time point derived lesions on ADC maps than DWI (pdetermined lesion volumes on ADC maps and DWI by both investigators correlated significantly with threshold-derived lesion volumes on ADC maps with the former method demonstrating a stronger correlation. There was also a better interrater agreement for ADC map analysis than for DWI analysis. Ischemic lesion determination by ADC was more accurate in final infarct prediction, rater independent, and provided exclusive information on ischemic lesion reversibility.

  15. On Describing Human White Matter Anatomy: The White Matter Query Language

    OpenAIRE

    Wassermann, Demian; Makris, Nikos; Rathi, Yogesh; Shenton, Martha; Kikinis, Ron; Kubicki, Marek; Westin, Carl-Fredrik

    2013-01-01

    The main contribution of this work is the careful syntactical definition of major white matter tracts in the human brain based on a neuroanatomist’s expert knowledge. We present a technique to formally describe white matter tracts and to automatically extract them from diffusion MRI data. The framework is based on a novel query language with a near-to-English textual syntax. This query language allows us to construct a dictionary of anatomical definitions describing white matter tracts. The d...

  16. Pittsburgh compound-B PET white matter imaging and cognitive function in late multiple sclerosis.

    Science.gov (United States)

    Zeydan, Burcu; Lowe, Val J; Schwarz, Christopher G; Przybelski, Scott A; Tosakulwong, Nirubol; Zuk, Samantha M; Senjem, Matthew L; Gunter, Jeffrey L; Roberts, Rosebud O; Mielke, Michelle M; Benarroch, Eduardo E; Rodriguez, Moses; Machulda, Mary M; Lesnick, Timothy G; Knopman, David S; Petersen, Ronald C; Jack, Clifford R; Kantarci, Kejal; Kantarci, Orhun H

    2018-05-01

    There is growing interest in white matter (WM) imaging with positron emission tomography (PET). We studied the association of cognitive function in late multiple sclerosis (MS) with cortical and WM Pittsburgh compound-B PET (PiB-PET) binding. In the population-based Mayo Clinic Study of Aging, 24 of 4869 participants had MS (12 underwent PiB-PET). Controls were age and sex matched (5:1). We used automated or semi-automated processing for quantitative image analyses and conditional logistic regression for group differences. MS patients had lower memory ( p = 0.03) and language ( p = 0.02) performance; smaller thalamic volumes ( p = 0.003); and thinner temporal ( p = 0.001) and frontal ( p = 0.045) cortices on magnetic resonance imaging (MRI) than controls. There was no difference in global cortical PiB standardized uptake value ratios between MS and controls ( p = 0.35). PiB uptake was lower in areas of WM hyperintensities compared to normal-appearing white matter (NAWM) in MS ( p = 0.0002). Reduced PiB uptake in both the areas of WM hyperintensities ( r = 0.65; p = 0.02) and NAWM ( r = 0.69; p = 0.01) was associated with decreased visuospatial performance in MS. PiB uptake in the cortex in late MS is not different from normal age-matched controls. PiB uptake in the WM in late MS may be a marker of the large network structures' integrity such as those involved in visuospatial performance.

  17. White matter microstructure in 22q11 deletion syndrome: a pilot diffusion tensor imaging and voxel-based morphometry study of children and adolescents

    NARCIS (Netherlands)

    Sundram, Frederick; Campbell, Linda E.; Azuma, Rayna; Daly, Eileen; Bloemen, Oswald J. N.; Barker, Gareth J.; Chitnis, Xavier; Jones, Derek K.; van Amelsvoort, Therese; Murphy, Kieran C.; Murphy, Declan G. M.

    2010-01-01

    Young people with 22q11 Deletion Syndrome (22q11DS) are at substantial risk for developing psychosis and have significant differences in white matter (WM) volume. However, there are few in vivo studies of both WM microstructural integrity (as measured using Diffusion Tensor (DT)-MRI) and WM volume

  18. A neurotological study of patients with pontine hyperintense lesions on T2 weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Toru; Tominaga, Satoru; Yukimasa, Akiko; Oku, Masaya; Sakagami, Masafumi [Hyogo Coll. of Medicine, Nishinomiya (Japan)

    2002-03-01

    Pontine hyperintense lesions seen on T2-weighted MRI were thought to be related to disequilibrium. Some of these lesions have a low signal on T1-weighted imaging, while others have an iso-signal. The purpose of this study was to clarify the relationship between neurological findings and pontine lesions detected by MRI. The subjects were 11 patients (6 males, 5 females; age range: 30 to 83 years [mean: 64.1 years]) with pontine hyperintense lesions identified on T2-weighted MRI. We compared the clinical signs and the MRI findings. Six of the patients had low-intensity areas on T1-weighted images, and the other 5 had iso-intensity areas. Six patients complained of vertigo, and 5 complained of dizziness. Eight complained of positionaly evoked disequilibrium. Positional nystagmus was seen in 4 patients. In 9 patients, abnormalities were found on the ENG test, including the saccadic eye movement test, ETT, and OKP. Numbness on the lips occurred in 2 patients, and cerebellar signs were present in 4. None of the patients had facial paralysis. Disequilibrium originating in the central nervous system was suggested in 10 patients. Clinical examinations revealed similar findings in patients with a low signal on T1-weighted MRI and those with an iso-signal. Our results indicate that pontine lesions identified by T2-weighted MRI cause vertigo or dizziness, and, in most cases, these lesions cause abnormal neurological or neurological abnormalities. (author)

  19. A neurotological study of patients with pontine hyperintense lesions on T2 weighted MRI

    International Nuclear Information System (INIS)

    Seo, Toru; Tominaga, Satoru; Yukimasa, Akiko; Oku, Masaya; Sakagami, Masafumi

    2002-01-01

    Pontine hyperintense lesions seen on T2-weighted MRI were thought to be related to disequilibrium. Some of these lesions have a low signal on T1-weighted imaging, while others have an iso-signal. The purpose of this study was to clarify the relationship between neurological findings and pontine lesions detected by MRI. The subjects were 11 patients (6 males, 5 females; age range: 30 to 83 years [mean: 64.1 years]) with pontine hyperintense lesions identified on T2-weighted MRI. We compared the clinical signs and the MRI findings. Six of the patients had low-intensity areas on T1-weighted images, and the other 5 had iso-intensity areas. Six patients complained of vertigo, and 5 complained of dizziness. Eight complained of positionaly evoked disequilibrium. Positional nystagmus was seen in 4 patients. In 9 patients, abnormalities were found on the ENG test, including the saccadic eye movement test, ETT, and OKP. Numbness on the lips occurred in 2 patients, and cerebellar signs were present in 4. None of the patients had facial paralysis. Disequilibrium originating in the central nervous system was suggested in 10 patients. Clinical examinations revealed similar findings in patients with a low signal on T1-weighted MRI and those with an iso-signal. Our results indicate that pontine lesions identified by T2-weighted MRI cause vertigo or dizziness, and, in most cases, these lesions cause abnormal neurological or neurological abnormalities. (author)

  20. Baryonic dark matter

    International Nuclear Information System (INIS)

    Uson, Juan M.

    2000-01-01

    Many searches for baryonic dark matter have been conducted but, so far, all have been unsuccessful. Indeed, no more than 1% of the dark matter can be in the form of hydrogen burning stars. It has recently been suggested that most of the baryons in the universe are still in the form of ionized gas so that it is possible that there is no baryonic dark matter. Although it is likely that a significant fraction of the dark matter in the Milky Way is in a halo of non-baryonic matter, the data do not exclude the possibility that a considerable amount, perhaps most of it, could be in a tenuous halo of diffuse ionized gas

  1. Tuberous sclerosis: diffusion MRI findings in the brain

    International Nuclear Information System (INIS)

    Sener, R.N.

    2002-01-01

    Diffusion MRI has mainly been used for detection of acute ischemia, and for distinction of cytotoxic and vasogenic edema. We applied diffusion MRI in patients with tuberous sclerosis in order to evaluate diffusion imaging characteristics of parenchymal changes. Five children with known tuberous sclerosis were included in this study. The MRI examinations were performed on a 1.5-T MR unit. Diffusion MRI was obtained using the echo-planar imaging sequence. Apparent diffusion coefficient (ADC) values from the abnormal brain parenchyma were calculated directly from automatically generated ADC maps. Seven normal children were available for comparison. In this control group the mean ADC value of the normal white matter was 0.84±0.12 x 10 -3 mm 2 /s. In tuberous sclerosis patients the mean ADC value of the white matter hamartomas (n=20) was apparently high (1.52±0.24 x 10 -3 mm 2 /s) compared with that of normal white matter. The ADC value of calcified hamartomas was ''zero''. The ADC value within a giant cell tumor was 0.89 x 10 -3 mm 2 /s, similar to that of normal cerebral white matter. The ADC maps were superior to b=1000 s/mm 2 (true diffusion) images with respect to lesion evaluation, and they provided mathematical information on tissue integrity. With respect to detection of the exact numbers and sizes of the parenchymal hamartomas fluid-attenuated inversion recovery images were superior to ADC maps. It is believed that diffusion MRI can be useful in evaluation of various parenchymal changes associated with tuberous sclerosis. Further studies on tuberous sclerosis, and on various brain lesions, would provide increasing data on this relatively new MRI sequence. (orig.)

  2. Diffusion and ADC-map images detect ongoing demyelination on subcortical white matter in an adult metachromatic leukodystrophy patient with autoimmune Hashimoto thyroiditis

    Science.gov (United States)

    Miura, Akiko; Kumabe, Yuri; Kimura, En; Yamashita, Satoshi; Ueda, Akihiko; Hirano, Teruyuki; Uchino, Makoto

    2010-01-01

    Adult-onset metachromatic leukodystrophy (MLD) often shows schizophrenia- or encephalopathy-like symptoms at an early stage, such as behavioural abnormalities, cognitive impairment, mood disorders and hallucinations. The authors report the case of an adult woman with MLD who had been given antipsychotic medication for schizophrenia. In the differential diagnosis, screening of auto-antibodies was important for ruling out other encephalopathies as she had a euthyroid Hashimoto thyroiditis. Diagnosis was based the results of MRI, nerve conduction velocity, sensory evoked potential, motor evoked potential, lysosomal enzyme activity and gene analysis studies. Brain MRI showed diffuse demyelination spreading from the deep white matter to subcortical area as high signals at the edges of these lesions in diffusion and apparent diffusion coefficient-map images with the U-fibres conserved. The authors diagnosed adult-onset MLD coexisting with euthyroid autoimmune Hashimoto thyroiditis. PMID:22798296

  3. Collective effects in diffuse ambiplasma

    International Nuclear Information System (INIS)

    Rogers, S.H.

    1981-01-01

    All laboratory evidence to date indicates that particles materialize from energy only in matter-antimatter pairs and, conversely, disappear only when such pairs annihilate. This observed law suggests that early in the Big Bang, when material and radiation were in equilibrium, the universe contained equal amounts of matter and antimatter. Since the earth, the solar system, and the neighboring stars, as implied by cosmic ray data, appear to be exclusively matter, their antimatter counterparts should by all rights exist elsewhere. Astronomical observations, however, have revealed no signs of antimatter on a large scale; in particular, the energetic gamma rays that would originate in the boundaries between matter and antimatter are not observed. The dilemma is resolved if the laboratory law is violated even minutely, a possibility that is now being tested by experiment. On the other hand, the dilemma disappears if the matter and antimatter exist in separate regions without, in effect, interacting. In this case there must be a repulsive force between the matter and antimatter that prevents them from mixing; in particular, such a force is crucial to the coexistence of large, diffuse regions akin to the galactic interstellar clouds. Predictions of the outcome of matter-antimatter contact are usually based entirely on binary collisions. This disseration explores the possibility that collective effects dominate interactions between diffuse matter and antimatter and give rise to the necessary repulsive force. Some years ago, a mechanism was proposed in which a thin, magnetized layer of ambiplasma kept matter and antimatter plasmas separated with the energy released in occasional annihilation

  4. Left hemisphere fractional anisotropy increase in noise-induced tinnitus: a diffusion tensor imaging (DTI) study of white matter tracts in the brain.

    Science.gov (United States)

    Benson, Randall R; Gattu, Ramtilak; Cacace, Anthony T

    2014-03-01

    Diffusion tensor imaging (DTI) is a contemporary neuroimaging modality used to study connectivity patterns and microstructure of white matter tracts in the brain. The use of DTI in the study of tinnitus is a relatively unexplored methodology with no studies focusing specifically on tinnitus induced by noise exposure. In this investigation, participants were two groups of adults matched for etiology, age, and degree of peripheral hearing loss, but differed by the presence or absence (+/-) of tinnitus. It is assumed that matching individuals on the basis of peripheral hearing loss, allows for differentiating changes in white matter microstructure due to hearing loss from changes due to the effects of chronic tinnitus. Alterations in white matter tracts, using the fractional anisotropy (FA) metric, which measures directional diffusion of water, were quantified using tract-based spatial statistics (TBSS) with additional details provided by in vivo probabilistic tractography. Our results indicate that 10 voxel clusters differentiated the two groups, including 9 with higher FA in the group with tinnitus. A decrease in FA was found for a single cluster in the group with tinnitus. However, seven of the 9 clusters with higher FA were in left hemisphere thalamic, frontal, and parietal white matter. These foci were localized to the anterior thalamic radiations and the inferior and superior longitudinal fasciculi. The two right-sided clusters with increased FA were located in the inferior fronto-occipital fasciculus and superior longitudinal fasciculus. The only decrease in FA for the tinnitus-positive group was found in the superior longitudinal fasciculus of the left parietal lobe. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Combining voxel-based morphometry and diffusion tensor imaging to detect age-related brain changes.

    Science.gov (United States)

    Lehmbeck, Jan T; Brassen, Stefanie; Weber-Fahr, Wolfgang; Braus, Dieter F

    2006-04-03

    The present study combined optimized voxel-based morphometry and diffusion tensor imaging to detect age-related brain changes. We compared grey matter density maps (grey matter voxel-based morphometry) and white matter fractional anisotropy maps (diffusion tensor imaging-voxel-based morphometry) between two groups of 17 younger and 17 older women. Older women exhibited reduced white matter fractional anisotropy as well as decreased grey matter density most prominently in the frontal, limbic, parietal and temporal lobes. A discriminant analysis identified four frontal and limbic grey and white matter areas that separated the two groups most effectively. We conclude that grey matter voxel-based morphometry and diffusion tensor imaging voxel-based morphometry are well suited for the detection of age-related changes and their combination provides high accuracy when detecting the neural correlates of aging.

  6. Tract-specific analysis of white matter pathways in healthy subjects: a pilot study using diffusion tensor MRI

    Energy Technology Data Exchange (ETDEWEB)

    Yasmin, Hasina; Abe, Osamu; Nakata, Yasuhiro; Hayashi, Naoto; Masutani, Yoshitaka; Goto, Masami; Ohtomo, Kuni [University of Tokyo, Department of Radiology, Bunkyo-ku, Tokyo (Japan); Aoki, Shigeki [Juntendo University, Department of Radiology, Bunkyo-ku, Tokyo (Japan)

    2009-12-15

    To date, very scant data is available regarding normal diffusion properties of white matter (WM) fibers. The present study aimed to initiate the establishment of a database of normal diffusion tensor metrics of cerebral WM fibers, including the uncinate fasciculus (UF), posterior cingulum (PC), fornix, and corticospinal tract (CST) for healthy adults using tract-specific analysis by diffusion tensor tractography (DTT). We also attempted to clarify whether age and laterality exerted any effects on this study group. DTT of WM fibers were generated for 100 healthy subjects, then mean diffusivity (MD) and fractional anisotropy (FA) of the tracts were measured. Pearson correlation analysis was used to evaluate age relationships. Paired t testing was used to compare hemispheric asymmetry. Interobserver correlation tests were also performed. Our results showed FA values for UF (right, 0.42 {+-} 0.03; left, 0.40{+-}0.03), PC (0.51 {+-} 0.06, 0.52 {+-} 0.06), fornix (0.37 {+-} 0.06, 0.38 {+-} 0.06), CST (0.70 {+-} 0.06, 0.69 {+-} 0.07), and MD values for UF (0.81 {+-} 0.03, 0.82 {+-} 0.04), PC (0.72 {+-} 0.03, 0.72 {+-} 0.04), fornix (1.86 {+-} 0.32, 1.94 {+-} 0.37), and CST (0.72 {+-} 0.03, 0.74 {+-} 0.04). We identified a significant positive correlation between age and MD in the right UF and bilateral fornices, and a negative correlation between age and FA in bilateral fornices. Hemispheric asymmetry was observed in FA of UF (right > left) and MD of CST (left > right). The results constitute a normative dataset for diffusion parameters of four WM tracts that can be used to identify, characterize, and establish the significance of changes in diseases affecting specific tracts. (orig.)

  7. Regional variation of white matter development in the cat brain revealed by ex vivo diffusion MR tractography.

    Science.gov (United States)

    Dai, Guangping; Das, Avilash; Hayashi, Emiko; Chen, Qin; Takahashi, Emi

    2016-11-01

    Three-dimensional reconstruction of developing fiber pathways is essential to assessing the developmental course of fiber pathways in the whole brain. We applied diffusion spectrum imaging (DSI) tractography to five juvenile ex vivo cat brains at postnatal day (P) 35, when the degree of myelination varies across brain regions. We quantified diffusion properties (fractional anisotropy [FA] and apparent diffusion coefficient [ADC]) and other measurements (number, volume, and voxel count) on reconstructed pathways for projection (cortico-spinal and thalamo-cortical), corpus callosal, limbic (cingulum and fornix), and association (cortico-cortical) pathways, and characterized regional differences in maturation patterns by assessing diffusion properties. FA values were significantly higher in cortico-cortical pathways within the right hemisphere compared to those within the left hemisphere, while the other measurements for the cortico-cortical pathways within the hemisphere did not show asymmetry. ADC values were not asymmetric in both types of pathways. Interestingly, tract count and volume were significantly larger in the left thalamo-cortical pathways compared to the right thalamo-cortical pathways. The bilateral thalamo-cortical pathways showed high FA values compared to the other fiber pathways. On the other hand, ADC values did not show any differences across pathways studied. These results demonstrate that DSI tractography successfully depicted regional variations of white matter tracts during development when myelination is incomplete. Low FA and high ADC values in the cingulum bundle suggest that the cingulum bundle is less mature than the others at this developmental stage. Copyright © 2016 ISDN. Published by Elsevier Ltd. All rights reserved.

  8. Incidence of ischemic lesions by diffusion-weighted imaging after carotid endarterectomy with routine shunt usage

    International Nuclear Information System (INIS)

    Inoue, Tomohiro; Tsutsumi, Kazuo; Adachi, Shinobu; Tanaka, Shota; Yako, Kyoko; Saito, Kuniaki; Kunii, Naoto; Maeda, Keiitirou

    2006-01-01

    Temporary intraluminal shunt was used during 72 consecutive carotid endarterectomies (CEAs) in 61 patients (bilateral CEA in 11 patients) during October 2001 and September 2005. The medical records of these patients were retrospectively reviewed. All procedures were performed with routine shunt insertion without monitoring such as electroencephalography. Pre- and postoperative diffusion-weighted magnetic resonance (MR) imaging was used to detect ischemic complications. Postoperative angiography was performed in 70 cases to detect abnormalities such as major stenosis or dissection of the distal end. Symptomatic ischemic complication occurred in one patient at 1 month. Postoperative diffusion-weighted MR imaging detected new hyperintense lesions in three patients including the symptomatic patient. Postoperative angiography confirmed that the distal end was satisfactory in all cases. The incidence of ischemic lesions of embolic origin after CEA with routine shunt usage is acceptably low if the procedure of shunt device insertion and removal is meticulously conducted. (author)

  9. Conceptual elaboration versus direct lexical access in WAIS-similarities: differential effects of white-matter lesions and gray matter volumes.

    Science.gov (United States)

    Fernaeus, Sven-Erik; Hellström, Åke

    2017-09-18

    Wechsler Adult Intelligence Scale (WAIS) subscale Similarities have been classified as a test of either verbal comprehension or of inductive reasoning. The reason may be that items divide into two categories. We tested the hypothesis of heterogeneity of items in WAIS-Similarities. Consecutive patients at a memory clinic and healthy controls participated in the study. White-matter hyperintensities (WMHs) and normalized temporal lobe volumes were measured based on Magnetic resonance Imaging (MRI), and tests of verbal memory and attention were used in addition to WAIS-Similarities to collect behavioural data. Factor analysis supported the hypothesis that two factors are involved in the performance of WAIS-similarities: (1) semiautomatic lexical access and (2) conceptual elaboration. These factors were highly correlated but provided discriminative diagnostic information: In logistic regression analyses, scores of the lexical access factor and of the conceptual elaboration factor discriminated patients with mild cognitive impairment from Alzheimer's disease patients and from healthy controls, respectively. High scores of WMH, indicating periventricular white-matter lesions, predicted factor scores of direct lexical access but not those of conceptual elaboration, which were predicted only by medial and lateral temporal lobe volumes.

  10. White matter abnormalities in treatment-naive adolescents at the earliest stages of Anorexia Nervosa: A diffusion tensor imaging study.

    Science.gov (United States)

    Gaudio, Santino; Quattrocchi, Carlo Cosimo; Piervincenzi, Claudia; Zobel, Bruno Beomonte; Montecchi, Francesca Romana; Dakanalis, Antonios; Riva, Giuseppe; Carducci, Filippo

    2017-08-30

    Few studies have examined white matter (WM) integrity in long-lasting Anorexia Nervosa (AN) patients using Diffusion Tensor Imaging (DTI). In this paper, we investigated WM integrity at the earliest stages of AN (i.e. less than 6 months duration). Fourteen treatment-naive female adolescents with AN restrictive type (AN-r) in its earliest stages and 15 age-matched healthy females received brain MRI. Fractional Anisotropy (FA), Axial Diffusivity (AD), Radial diffusivity (RD), and Mean Diffusivity (MD) maps were computed from DTI data using Tract-Based Spatial Statistics analysis. AN-r patients showed FA decreases compared to controls (p FWE < 0.05) mainly in left anterior and superior corona radiata and left superior longitudinal fasciculus. AN-r patients also showed decreased AD in superior longitudinal fasciculus bilaterally and left superior and anterior corona radiata, (p FWE < 0.05). No significant differences were found in RD and MD values between the two groups. FA and AD integrity appears to be specifically affected at the earliest stages of AN. Alterations in the microstructural properties of the above mentioned tracts, also involved in cognitive control and visual perception and processing, may be early mechanisms of vulnerability/resilience of WM in AN and sustain the key symptoms of AN, such as impaired cognitive flexibility and body image distortion. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  11. A review of anisotropic conductivity models of brain white matter based on diffusion tensor imaging.

    Science.gov (United States)

    Wu, Zhanxiong; Liu, Yang; Hong, Ming; Yu, Xiaohui

    2018-06-01

    The conductivity of brain tissues is not only essential for electromagnetic source estimation (ESI), but also a key reflector of the brain functional changes. Different from the other brain tissues, the conductivity of whiter matter (WM) is highly anisotropic and a tensor is needed to describe it. The traditional electrical property imaging methods, such as electrical impedance tomography (EIT) and magnetic resonance electrical impedance tomography (MREIT), usually fail to image the anisotropic conductivity tensor of WM with high spatial resolution. The diffusion tensor imaging (DTI) is a newly developed technique that can fulfill this purpose. This paper reviews the existing anisotropic conductivity models of WM based on the DTI and discusses their advantages and disadvantages, as well as identifies opportunities for future research on this subject. It is crucial to obtain the linear conversion coefficient between the eigenvalues of anisotropic conductivity tensor and diffusion tensor, since they share the same eigenvectors. We conclude that the electrochemical model is suitable for ESI analysis because the conversion coefficient can be directly obtained from the concentration of ions in extracellular liquid and that the volume fraction model is appropriate to study the influence of WM structural changes on electrical conductivity. Graphical abstract ᅟ.

  12. Diffusion in compacted betonite

    International Nuclear Information System (INIS)

    Muurinen, A.; Rantanen, J.

    1985-01-01

    The objective of this report is to collect the literature bearing on the diffusion in compacted betonite, which has been suggested as possible buffer material for the disposal of spent fuel. Diffusion in a porous, water-saturated material is usually described as diffusion in the pore-water where sorption on the solid matter can delay the migration in the instationary state. There are also models which take into consideration that the sorbed molecules can also move while being sorbed. Diffusion experiments in compacted bentonite have been reported by many authors. Gases, anions, cations and actinides have been used as diffusing molecules. The report collects the results and the information on the measurement methods. On the basis of the results can be concluded that different particles possibly follow different diffusion mechanisms. The parameters which affect the diffusion seem to be for example the size, the electric charge and the sorption properties of the diffusing molecule. The report also suggest the parameters to be used in the diffusion calculation of the safety analyses of spent fuel disposal. (author)

  13. Capsule, septum, and T2 hyperintense foci for differentiation between large hepatocellular carcinoma (≥5 cm) and intrahepatic cholangiocarcinoma on gadoxetic acid MRI

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Jiyoung; Hong, Seong Sook; Kim, Hyun-joo [Soonchunhyang University College of Medicine, Department of Radiology, Seoul Hospital, Seoul (Korea, Republic of); Kim, Young Kon; Min, Ji Hye; Jeong, Woo Kyung [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Samsung Medical Center, Seoul (Korea, Republic of); Choi, Seo-Youn [Soonchunhyang University College of Medicine, Department of Radiology, Bucheon Hospital, Bucheon (Korea, Republic of); Ahn, Soohyun; Ahn, Hyeon Seon [Research Institute for Future Medicine, Biostatistics and Clinical Epidemiology Center, Samsung Medical Center, Seoul (Korea, Republic of)

    2017-11-15

    To determine the added value of capsule, septum, and T2 hyperintense foci for differentiating large hepatocellular carcinoma (HCC; ≥ 5 cm) from intrahepatic cholangiocarcinoma (ICC) using gadoxetic acid MRI. The study included 116 patients (94 men, 22 women; mean age, 56.8 years) with surgically confirmed HCCs (n = 87, 5.0-18.0 cm) or ICCs (n = 29, 5.0-14.0 cm) who underwent gadoxetic acid MRI. Three observers independently reviewed MRIs in two sessions, examining enhancement patterns only and then adding capsule, septum, and T2 hyperintense foci. Reviewers used a five-point scale to score accuracy, sensitivity, and specificity. A significant increase was observed in accuracy when ancillary features (96.1-98.3%) were added compared to enhancement pattern only (83.6-88.4%; p ≤ 0.02). Sensitivity was significantly increased with combined reading (97.1-98.3%) compared to enhancement features only (81.6-88.5%; p ≤ 0.006) for two observers, with no difference in specificity (84.5-89.7% vs. 86.2-98.3%; p > 0.05). We found substantial to excellent interobserver agreement for ancillary features (0.598-0.976). Adding capsule, septum, and T2 hyperintense foci to enhancement patterns for gadoxetic acid MRI increased diagnostic performance for characterizing large HCC by differentiating it from ICC. (orig.)

  14. The spatial distribution of age-related white matter changes as a function of vascular risk factors--results from the LADIS study

    DEFF Research Database (Denmark)

    Rostrup, E; Gouw, A A; Vrenken, H

    2012-01-01

    White matter hyperintensities (WMH) are a frequent finding on brain MRI of elderly subjects, and have been associated with various risk factors, as well as with development of cognitive and functional impairment. While an overall association between WMH load and risk factors is well described...... associations were found for age, gender and hypertension. Different distribution patterns were found for men and women. Further, increased probability was found in association with self-reported alcohol and tobacco consumption, as well as in those with a history of migraine. It is concluded that the location...... of WMH is dependent on the risk factors involved pointing towards a regionally different pathogenesis and/or vulnerability of the white matter....

  15. Diffusion-weighted imaging and magnetic resonance spectroscopy of sporadic Creutzfeldt-Jakob disease: correlation with clinical course

    International Nuclear Information System (INIS)

    Kim, Jae Hyoung; Choi, Byung Se; Jung, Cheolkyu; Chang, YoungHee; Kim, SangYun

    2011-01-01

    Sporadic Creutzfeldt-Jakob disease (sCJD) is a fatal disease with variable clinical courses. The presence or absence of basal ganglia (BG) involvement has been reported to be associated with clinical course. We investigated the association of clinical course of sCJD with diffusion-weighted imaging (DWI) and MR spectroscopy (MRS) as well as BG involvement at early stage. DWI and single voxel proton MRS were performed in 14 patients with sCJD during the initial diagnostic workup. Apparent diffusion coefficient (ADC) and metabolites were measured in medial occipitoparietal cortices where large hyperintense DWI lesions were found in all patients. The presence or absence of BG involvement, ADC, N-acetylaspartate (NAA)/creatine (Cr) ratios, and choline (Cho)/Cr ratios were correlated with disease duration (i.e., the time from the symptom onset to death). The disease duration ranged from 2 to 31 months (median, 16). Hyperintense DWI lesions were observed bilaterally in both cortices and basal ganglia in eight patients and in cortices alone in six patients. Patients with BG involvement had shorter disease duration (median, 6.8 versus 20.5; p = 0.039) than those without and lower NAA/Cr ratios (median, 1.41 versus 2.03; p = 0.001). ADC and Cho/Cr ratios were not significantly different between the patients with BG involvement and those without. By multiple regression analysis, NAA/Cr ratios had the greatest correlation with the disease duration (p = 0.029). The disease duration of sCJD was variable. NAA/Cr ratios of the affected brain at the early stage of sCJD can be used as a useful parameter in predicting the clinical course. (orig.)

  16. Diffusion-weighted imaging and magnetic resonance spectroscopy of sporadic Creutzfeldt-Jakob disease: correlation with clinical course

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Hyoung; Choi, Byung Se; Jung, Cheolkyu [Seoul National University Bundang Hospital, Department of Radiology, Seoul National University College of Medicine, Seongnam-si (Korea, Republic of); Chang, YoungHee; Kim, SangYun [Seoul National University Bundang Hospital, Department of Neurology, Seoul National University College of Medicine, Seongnam-si (Korea, Republic of)

    2011-12-15

    Sporadic Creutzfeldt-Jakob disease (sCJD) is a fatal disease with variable clinical courses. The presence or absence of basal ganglia (BG) involvement has been reported to be associated with clinical course. We investigated the association of clinical course of sCJD with diffusion-weighted imaging (DWI) and MR spectroscopy (MRS) as well as BG involvement at early stage. DWI and single voxel proton MRS were performed in 14 patients with sCJD during the initial diagnostic workup. Apparent diffusion coefficient (ADC) and metabolites were measured in medial occipitoparietal cortices where large hyperintense DWI lesions were found in all patients. The presence or absence of BG involvement, ADC, N-acetylaspartate (NAA)/creatine (Cr) ratios, and choline (Cho)/Cr ratios were correlated with disease duration (i.e., the time from the symptom onset to death). The disease duration ranged from 2 to 31 months (median, 16). Hyperintense DWI lesions were observed bilaterally in both cortices and basal ganglia in eight patients and in cortices alone in six patients. Patients with BG involvement had shorter disease duration (median, 6.8 versus 20.5; p = 0.039) than those without and lower NAA/Cr ratios (median, 1.41 versus 2.03; p = 0.001). ADC and Cho/Cr ratios were not significantly different between the patients with BG involvement and those without. By multiple regression analysis, NAA/Cr ratios had the greatest correlation with the disease duration (p = 0.029). The disease duration of sCJD was variable. NAA/Cr ratios of the affected brain at the early stage of sCJD can be used as a useful parameter in predicting the clinical course. (orig.)

  17. Headache, migraine, and structural brain lesions and function: population based Epidemiology of Vascular Ageing-MRI study

    International Nuclear Information System (INIS)

    Kurth, T.; Mohamed, S.; Zhu, Y.C.; Dufouil, C.; Tzourio, Ch.; Kurth, T.; Zhu, Y.C.; Dufouil, C.; Tzourio, Ch.; Kurth, T.; Maillard, P.; Mazoyer, B.; Zhu, Y.C.; Chabriat, H.; Bousser, M.G.; Tzourio, Ch.; Zhu, Y.C.; Chabriat, H.; Bousser, M.G.; Mazoyer, B.

    2011-01-01

    Objective: To evaluate the association of overall and specific headaches with volume of white matter hyper-intensities, brain infarcts, and cognition. Design: Population based, cross sectional study. Setting: Epidemiology of Vascular Ageing study, Nantes, France. Participants: 780 participants (mean age 69, 58.5% women) with detailed headache assessment. Main outcome measures: Brain scans were evaluated for volume of white matter hyper-intensities (by fully automated imaging processing) and for classification of infarcts (by visual reading with a standardised assessment grid). Cognitive function was assessed by a battery of tests including the mini-mental state examination. Results: 163 (20.9%) participants reported a history of severe headache and 116 had migraine, of whom 17 (14.7%) reported aura symptoms. An association was found between any history of severe headache and increasing volume of white matter hyper-intensities. The adjusted odds ratio of being in the highest third for total volume of white matter hyper-intensities was 2.0 (95% confidence interval 1.3 to 3.1, P for trend 0.002) for participants with any history of severe headache when compared with participants without severe headache being in the lowest third. The association pattern was similar for all headache types. Migraine with aura was the only headache type strongly associated with volume of deep white matter hyper-intensities (highest third odds ratio 12.4, 1.6 to 99.4, P for trend 0.005) and with brain infarcts (3.4, 1.2 to 9.3). The location of infarcts was predominantly outside the cerebellum and brain stem. Evidence was lacking for cognitive impairment for any headache type with or without brain lesions. Conclusions: In this population based study, any history of severe headache was associated with an increased volume of white matter hyper-intensities. Migraine with aura was the only headache type associated with brain infarcts. Evidence that headache of any type by itself or in

  18. Fluid-attenuated inversion recovery vascular hyperintensities in predicting cerebral hyperperfusion after intracranial arterial stenting

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Chih-Cheng; Chen, David Yen-Ting; Tseng, Ying-Chi; Lee, Kun-Yu; Chiang, Chen-Hua; Chen, Chi-Jen [Taipei Medical University, Department of Radiology, Shuang-Ho Hospital, New Taipei City (China); Taipei Medical University, School of Medicine, College of Medicine, Taipei (China); Yan, Feng-Xian [Taipei Medical University, Department of Radiology, Shuang-Ho Hospital, New Taipei City (China)

    2017-08-15

    No reliable imaging sign predicting cerebral hyperperfusion after intracranial arterial stenting (IAS) had been described in the literature. This study evaluated the effect of fluid-attenuated inversion recovery vascular hyperintensities (FVHs), also called hyperintense vessel sign on T2-weighted fluid-attenuated inversion recovery (T2-FLAIR) MR images, in predicting significant increase in cerebral blood flow (CBF) defined by arterial spin labeling (ASL) after IAS. We reviewed ASL CBF images and T2-FLAIR MR images before (D0), 1 day after (D1), and 3 days after (D3) IAS of 16 patients. T1-weighted MR images were used as cerebral maps for calculating CBF. The changes in CBF values after IAS were calculated in and compared among stenting and nonstenting vascular territories. An increase more than 50% of CBF was considered as hyperperfusion. The effect of FVHs in predicting hyperperfusion was calculated. The D1 CBF value was significantly higher than the D0 CBF value in stenting vascular, contralateral anterior cerebral artery, contralateral middle cerebral artery, and contralateral posterior cerebral artery (PCA) territories (all P <.05). The D1 and D3 CBF values were significantly higher than the D0 CBF value in overall vascular (P <.001), overall nonstenting vascular (P <.001), and ipsilateral PCA (P <.05) territories. The rate of more than 50% increases in CBF was significantly higher in patients who exhibited asymmetric FVHs than in those who did not exhibit these findings. FVHs could be a critical predictor of a significant increase in CBF after IAS. (orig.)

  19. Fluid-attenuated inversion recovery vascular hyperintensities in predicting cerebral hyperperfusion after intracranial arterial stenting

    International Nuclear Information System (INIS)

    Wan, Chih-Cheng; Chen, David Yen-Ting; Tseng, Ying-Chi; Lee, Kun-Yu; Chiang, Chen-Hua; Chen, Chi-Jen; Yan, Feng-Xian

    2017-01-01

    No reliable imaging sign predicting cerebral hyperperfusion after intracranial arterial stenting (IAS) had been described in the literature. This study evaluated the effect of fluid-attenuated inversion recovery vascular hyperintensities (FVHs), also called hyperintense vessel sign on T2-weighted fluid-attenuated inversion recovery (T2-FLAIR) MR images, in predicting significant increase in cerebral blood flow (CBF) defined by arterial spin labeling (ASL) after IAS. We reviewed ASL CBF images and T2-FLAIR MR images before (D0), 1 day after (D1), and 3 days after (D3) IAS of 16 patients. T1-weighted MR images were used as cerebral maps for calculating CBF. The changes in CBF values after IAS were calculated in and compared among stenting and nonstenting vascular territories. An increase more than 50% of CBF was considered as hyperperfusion. The effect of FVHs in predicting hyperperfusion was calculated. The D1 CBF value was significantly higher than the D0 CBF value in stenting vascular, contralateral anterior cerebral artery, contralateral middle cerebral artery, and contralateral posterior cerebral artery (PCA) territories (all P <.05). The D1 and D3 CBF values were significantly higher than the D0 CBF value in overall vascular (P <.001), overall nonstenting vascular (P <.001), and ipsilateral PCA (P <.05) territories. The rate of more than 50% increases in CBF was significantly higher in patients who exhibited asymmetric FVHs than in those who did not exhibit these findings. FVHs could be a critical predictor of a significant increase in CBF after IAS. (orig.)

  20. Differences in Gaussian diffusion tensor imaging and non-Gaussian diffusion kurtosis imaging model-based estimates of diffusion tensor invariants in the human brain.

    Science.gov (United States)

    Lanzafame, S; Giannelli, M; Garaci, F; Floris, R; Duggento, A; Guerrisi, M; Toschi, N

    2016-05-01

    An increasing number of studies have aimed to compare diffusion tensor imaging (DTI)-related parameters [e.g., mean diffusivity (MD), fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD)] to complementary new indexes [e.g., mean kurtosis (MK)/radial kurtosis (RK)/axial kurtosis (AK)] derived through diffusion kurtosis imaging (DKI) in terms of their discriminative potential about tissue disease-related microstructural alterations. Given that the DTI and DKI models provide conceptually and quantitatively different estimates of the diffusion tensor, which can also depend on fitting routine, the aim of this study was to investigate model- and algorithm-dependent differences in MD/FA/RD/AD and anisotropy mode (MO) estimates in diffusion-weighted imaging of human brain white matter. The authors employed (a) data collected from 33 healthy subjects (20-59 yr, F: 15, M: 18) within the Human Connectome Project (HCP) on a customized 3 T scanner, and (b) data from 34 healthy subjects (26-61 yr, F: 5, M: 29) acquired on a clinical 3 T scanner. The DTI model was fitted to b-value =0 and b-value =1000 s/mm(2) data while the DKI model was fitted to data comprising b-value =0, 1000 and 3000/2500 s/mm(2) [for dataset (a)/(b), respectively] through nonlinear and weighted linear least squares algorithms. In addition to MK/RK/AK maps, MD/FA/MO/RD/AD maps were estimated from both models and both algorithms. Using tract-based spatial statistics, the authors tested the null hypothesis of zero difference between the two MD/FA/MO/RD/AD estimates in brain white matter for both datasets and both algorithms. DKI-derived MD/FA/RD/AD and MO estimates were significantly higher and lower, respectively, than corresponding DTI-derived estimates. All voxelwise differences extended over most of the white matter skeleton. Fractional differences between the two estimates [(DKI - DTI)/DTI] of most invariants were seen to vary with the invariant value itself as well as with MK

  1. Altered white matter microstructure associated with mild and moderate depressive symptoms in young adults, a diffusion tensor imaging study.

    Science.gov (United States)

    Ghazi Sherbaf, Farzaneh; Same, Kaveh; Ashraf-Ganjouei, Amir; Aarabi, Mohammad H

    2018-05-23

    In the context of growing evidence supporting disturbed neural connectivity in the pathogenesis of depressive symptoms, we used the diffusion tensor imaging technique to investigate white matter disruptions in previously undiagnosed and hence treatment-naive young adults with mild and moderate depressive symptoms screened by Beck's Depression Inventory test compared with age-matched and sex-matched healthy controls. This is the first diffusion tensor imaging study to assess minor forms of depression. We hypothesized that subthreshold depressive symptoms share the same neural disruptions as major depressive disorder (MDD). Each group included 47 participants with a mean age of 20.1±1.1 years. The exploratory region of interest method was used to assess integrity (fractional anisotropy and mean diffusivity) in 48 regions of the brain based on Mori atlas. Data were recruited from the Southwest University Longitudinal Imaging Multimodal Brain Data Repository. The following pathways showed significant microstructural changes by means of reduced fractional anisotropy in the group with depressive symptoms compared with normal participants: pontine crossing tract; genu of the corpus callosum; posterior limb of the internal capsule (bilaterally); and anterior, posterior, and superior corona radiata (bilaterally). None of the above regions, but the middle cerebellar peduncle and the right superior fronto-occipital fasciculus were shown to differ significantly in the mean diffusivity values between the two groups. On the basis of the current results, our findings provide evidence that the white matter impairments in the interhemispheric connections and frontal-subcortical neural circuits may play a key role in the pathogenesis of depression in young adults. The similarity of neural underpinnings in MDD and minor depressive disorder in this study further proves that these two mood disorders exist in a continuum, and milder depressive symptoms can herald a major episode

  2. Evaluation of deep gray matter volume, cortical thickness and white matter integrity in patients with typical absence epilepsy: a study using voxelwise-based techniques

    Energy Technology Data Exchange (ETDEWEB)

    Correa, D.G.; Ventura, N.; Tukamoto, G.; Gasparetto, E.L. [Federal University of Rio de Janeiro, Department of Radiology, Hospital Universitario Clementino Fraga Filho, Rio de Janeiro, RJ (Brazil); Clinica de Diagnostico por Imagem (CDPI), Rio de Janeiro (Brazil); Zimmermann, N. [Federal University of Rio de Janeiro, Department of Radiology, Hospital Universitario Clementino Fraga Filho, Rio de Janeiro, RJ (Brazil); Pontifical Catholic University of Rio Grande do Sul, Department of Psychology, Porto Alegre (Brazil); Doring, T.M. [Clinica de Diagnostico por Imagem (CDPI), Rio de Janeiro (Brazil); Leme, J.; Pereira, M. [Federal University of Rio de Janeiro, Department of Radiology, Hospital Universitario Clementino Fraga Filho, Rio de Janeiro, RJ (Brazil); Andrea, I. d' ; Rego, C.; Alves-Leon, S.V. [Federal University of Rio de Janeiro, Department of Neurology, Epilepsy Center, Hospital Universitario Clementino Fraga Filho, Rio de Janeiro (Brazil)

    2017-03-15

    The objective of this study was to evaluate the cortical thickness and the volume of deep gray matter structures, measured from 3D T1-weighted gradient echo imaging, and white matter integrity, by diffusion tensor imaging (DTI) in patients with typical absence epilepsy (AE). Patients (n = 19) with typical childhood AE and juvenile AE, currently taking antiepileptic medication, were compared with control subjects (n = 19), matched for gender and age. 3D T1 magnetization-prepared rapid gradient echo-weighted imaging and DTI along 30 noncolinear directions were performed using a 1.5-T MR scanner. FreeSurfer was used to perform cortical volumetric reconstruction and segmentation of deep gray matter structures. For tract-based spatial statistics analysis of DTI, a white matter skeleton was created, along with a permutation-based inference with 5000 permutations. A threshold of p < 0.05 was used to identify abnormalities in fractional anisotropy (FA). The mean, radial, and axial diffusivities were also projected onto the mean FA skeleton. Patients with AE presented decreased FA and increased mean diffusivity and radial diffusivity values in the genu and the body of the corpus callosum and right anterior corona radiata, as well as decreased axial diffusivity in the left posterior thalamic radiation, inferior cerebellar peduncle, right cerebral peduncle, and right corticospinal tract. However, there were no significant differences in cortical thickness or deep gray matter structure volumes between patients with AE and controls. Abnormalities found in white matter integrity may help to better understand the pathophysiology of AE and optimize diagnosis and treatment strategies. (orig.)

  3. Evaluation of deep gray matter volume, cortical thickness and white matter integrity in patients with typical absence epilepsy: a study using voxelwise-based techniques

    International Nuclear Information System (INIS)

    Correa, D.G.; Ventura, N.; Tukamoto, G.; Gasparetto, E.L.; Zimmermann, N.; Doring, T.M.; Leme, J.; Pereira, M.; Andrea, I. d'; Rego, C.; Alves-Leon, S.V.

    2017-01-01

    The objective of this study was to evaluate the cortical thickness and the volume of deep gray matter structures, measured from 3D T1-weighted gradient echo imaging, and white matter integrity, by diffusion tensor imaging (DTI) in patients with typical absence epilepsy (AE). Patients (n = 19) with typical childhood AE and juvenile AE, currently taking antiepileptic medication, were compared with control subjects (n = 19), matched for gender and age. 3D T1 magnetization-prepared rapid gradient echo-weighted imaging and DTI along 30 noncolinear directions were performed using a 1.5-T MR scanner. FreeSurfer was used to perform cortical volumetric reconstruction and segmentation of deep gray matter structures. For tract-based spatial statistics analysis of DTI, a white matter skeleton was created, along with a permutation-based inference with 5000 permutations. A threshold of p < 0.05 was used to identify abnormalities in fractional anisotropy (FA). The mean, radial, and axial diffusivities were also projected onto the mean FA skeleton. Patients with AE presented decreased FA and increased mean diffusivity and radial diffusivity values in the genu and the body of the corpus callosum and right anterior corona radiata, as well as decreased axial diffusivity in the left posterior thalamic radiation, inferior cerebellar peduncle, right cerebral peduncle, and right corticospinal tract. However, there were no significant differences in cortical thickness or deep gray matter structure volumes between patients with AE and controls. Abnormalities found in white matter integrity may help to better understand the pathophysiology of AE and optimize diagnosis and treatment strategies. (orig.)

  4. FADTTS: functional analysis of diffusion tensor tract statistics.

    Science.gov (United States)

    Zhu, Hongtu; Kong, Linglong; Li, Runze; Styner, Martin; Gerig, Guido; Lin, Weili; Gilmore, John H

    2011-06-01

    The aim of this paper is to present a functional analysis of a diffusion tensor tract statistics (FADTTS) pipeline for delineating the association between multiple diffusion properties along major white matter fiber bundles with a set of covariates of interest, such as age, diagnostic status and gender, and the structure of the variability of these white matter tract properties in various diffusion tensor imaging studies. The FADTTS integrates five statistical tools: (i) a multivariate varying coefficient model for allowing the varying coefficient functions in terms of arc length to characterize the varying associations between fiber bundle diffusion properties and a set of covariates, (ii) a weighted least squares estimation of the varying coefficient functions, (iii) a functional principal component analysis to delineate the structure of the variability in fiber bundle diffusion properties, (iv) a global test statistic to test hypotheses of interest, and (v) a simultaneous confidence band to quantify the uncertainty in the estimated coefficient functions. Simulated data are used to evaluate the finite sample performance of FADTTS. We apply FADTTS to investigate the development of white matter diffusivities along the splenium of the corpus callosum tract and the right internal capsule tract in a clinical study of neurodevelopment. FADTTS can be used to facilitate the understanding of normal brain development, the neural bases of neuropsychiatric disorders, and the joint effects of environmental and genetic factors on white matter fiber bundles. The advantages of FADTTS compared with the other existing approaches are that they are capable of modeling the structured inter-subject variability, testing the joint effects, and constructing their simultaneous confidence bands. However, FADTTS is not crucial for estimation and reduces to the functional analysis method for the single measure. Copyright © 2011 Elsevier Inc. All rights reserved.

  5. Executive Functions in Healthy Older Adults Are Differentially Related to Macro- and Microstructural White Matter Characteristics of the Cerebral Lobes

    Directory of Open Access Journals (Sweden)

    Sarah Hirsiger

    2017-11-01

    Full Text Available Aging is associated with microstructural white matter (WM changes. WM microstructural characteristics, measured with diffusion tensor imaging (DTI, are different in normal appearing white matter (NAWM and WM hyperintensities (WMH. It is largely unknown how the microstructural properties of WMH are associated with cognition and if there are regional effects for specific cognitive domains. We therefore examined within 200 healthy older participants (a differences in microstructural characteristics of NAWM and WMH per cerebral lobe; and (b the association of macrostructural (WMH volume and microstructural characteristics (within NAWM and WMH separately of each lobe with measures of executive function and processing speed. Multi-modal imaging (i.e., T1, DTI, and FLAIR was used to assess WM properties. The Stroop and the Trail Making Test were used to measure inhibition, task-switching (both components of executive function, and processing speed. We observed that age was associated with deterioration of white matter microstructure of the NAWM, most notably in the frontal lobe. Older participants had larger WMH volumes and lowest fractional anisotropy values within WMH were found in the frontal lobe. Task-switching was associated with cerebral NAWM volume and NAWM volume of all lobes. Processing speed was associated with total NAWM volume, and microstructural properties of parietal NAWM, the parietal WMH, and the temporal NAWM. Task-switching was related to microstructural properties of WMH of the frontal lobe and WMH volume of the parietal lobe. Our results confirm that executive functioning and processing speed are uniquely associated with macro- and microstructural properties of NAWM and WMH. We further demonstrate for the first time that these relationships differ by lobar region. This warrants the consideration of these distinct WM indices when investigating cognitive function.

  6. Diffusion Tensor Imaging: Application to the Study of the Developing Brain

    Science.gov (United States)

    Cascio, Carissa J.; Gerig, Guido; Piven, Joseph

    2007-01-01

    Objective: To provide an overview of diffusion tensor imaging (DTI) and its application to the study of white matter in the developing brain in both healthy and clinical samples. Method: The development of DTI and its application to brain imaging of white matter tracts is discussed. Forty-eight studies using DTI to examine diffusion properties of…

  7. Diffusion tensor studies and voxel-based morphometry of the temporal lobe to determine the cognitive prognosis in cases of Alzheimer's disease and mild cognitive impairment: Do white matter changes precede gray matter changes?

    Science.gov (United States)

    Taoka, Toshiaki; Yasuno, Fumihiko; Morikawa, Masayuki; Inoue, Makoto; Kiuchi, Kuniaki; Kitamura, Soichiro; Matsuoka, Kiwamu; Kishimoto, Toshifumi; Kichikawa, Kimihiko; Naganawa, Shinji

    2016-01-01

    The purpose of the current study was to assess the feasibility of diffusion tensor imaging (DTI) parameters for determining the prognosis of Alzheimer's disease (AD). We also analyzed the correlation among DTI, voxel-based morphometry (VBM), and results of the mini-mental state examination (MMSE). The subjects of this prospective study were patients with AD and mild cognitive impairment. We performed annual follow-ups with DTI, VBM, and MMSE for 2 or 3 years. On DTI, the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of the uncinate fascicles were measured. VBM was performed to provide a z-score for the parahippocampal gyrus. The correlations among these factors were evaluated in the same period and the next period of the follow-up study. For evaluation of the same period, both DTI parameters and z-scores showed statistically significant correlations with the MMSE score. Also for evaluation of the next period, both DTI parameters and z-scores showed statistically significant correlations with the MMSE score of the next period. We observed a statistically significant correlation between the ADC value of the uncinate fascicles and the z-score of the next period. Diffusion tensor parameters (ADC and FA) of the uncinate fascicles correlated well with cognitive function in the next year and seemed to be feasible for use as biomarkers for predicting the progression of AD. In addition, the white matter changes observed in the ADC seemed to precede changes in the gray matter volume of the parahippocampal gyrus that were represented by z-scores of VBM.

  8. Solar systems diffusion in local markets

    International Nuclear Information System (INIS)

    Sidiras, D.K.; Koukios, E.G.

    2004-01-01

    This paper reports on a study of the driving forces and barriers of the spectacular diffusion of solar energy use for domestic hot-water production in Greece. Through the various kinds of questionnaires used in this work, the main diffusion actors have been requested to grade the various diffusion factors identified by desk and preliminary field research. Households identify a number of economic (available family income), technical (new technologies), political (new incentives), and socio-cultural (sensitivity in energy matters) factors as dominant. According to the solar industry, advertising, distribution and quality control standards have to be added to the list of critical factors. Technical experts contribute with identifying, besides R and D, public awareness on energy matters. Solar collector diffusion, despite the fact that it has followed a market-driven mechanism, was revealed to be a multi-actor, multi-dimensional and multi-parametric phenomenon. Presently, the phenomenon is constrained by the available family income, with technology-related factors, i.e., research, and standardization quality control, playing increasing roles

  9. An introduction to visualization of diffusion tensor imaging and its applications

    NARCIS (Netherlands)

    Vilanova, A.; Zhang, S.; Kindlmann, G.; Laidlaw, D.H.; Weickert, J.; Hagen, H.

    2005-01-01

    Summary. Water diffusion is anisotropic in organized tissues such as white matter and muscle. Diffusion tensor imaging (DTI), a non-invasive MR technique, measures water self-diffusion rates and thus gives an indication of the underlying tissue microstructure. The diffusion rate is often expressed

  10. Diffusion Tensor Imaging of Heterotopia: Changes of Fractional Anisotropy during Radial Migration of Neurons

    Science.gov (United States)

    Kim, Jinna

    2010-01-01

    Purpose Diffusion tensor imaging provides better understanding of pathophysiology of congenital anomalies, involving central nervous system. This study was aimed to specify the pathogenetic mechanism of heterotopia, proved by diffusion tensor imaging, and establish new findings of heterotopia on fractional anisotropy maps. Materials and Methods Diffusion-weighted imaging data from 11 patients (M : F = 7 : 4, aged from 1 to 22 years, mean = 12.3 years) who visited the epilepsy clinic and received a routine seizure protocol MRI exam were retrospectively analyzed. Fractional anisotropy (FA) maps were generated from diffusion tensor imaging of 11 patients with heterotopia. Regions of interests (ROI) were placed in cerebral cortex, heterotopic gray matter and deep gray matter, including putamen. ANOVA analysis was performed for comparison of different gray matter tissues. Results Heterotopic gray matter showed signal intensities similar to normal gray matter on T1 and T2 weighted MRI. The measured FA of heterotopic gray matter was higher than that of cortical gray matter (0.236 ± 0.011 vs. 0.169 ± 0.015, p < 0.01, one way ANOVA), and slightly lower than that of deep gray matter (0.236 ± 0.011 vs. 0.259 ± 0.016, p < 0.01). Conclusion Increased FA of heterotopic gray matter suggests arrested neuron during radial migration and provides better understanding of neurodevelopment. PMID:20499428

  11. Spatial Mapping of Translational Diffusion Coefficients Using Diffusion Tensor Imaging: A Mathematical Description.

    Science.gov (United States)

    Shetty, Anil N; Chiang, Sharon; Maletic-Savatic, Mirjana; Kasprian, Gregor; Vannucci, Marina; Lee, Wesley

    2014-01-01

    In this article, we discuss the theoretical background for diffusion weighted imaging and diffusion tensor imaging. Molecular diffusion is a random process involving thermal Brownian motion. In biological tissues, the underlying microstructures restrict the diffusion of water molecules, making diffusion directionally dependent. Water diffusion in tissue is mathematically characterized by the diffusion tensor, the elements of which contain information about the magnitude and direction of diffusion and is a function of the coordinate system. Thus, it is possible to generate contrast in tissue based primarily on diffusion effects. Expressing diffusion in terms of the measured diffusion coefficient (eigenvalue) in any one direction can lead to errors. Nowhere is this more evident than in white matter, due to the preferential orientation of myelin fibers. The directional dependency is removed by diagonalization of the diffusion tensor, which then yields a set of three eigenvalues and eigenvectors, representing the magnitude and direction of the three orthogonal axes of the diffusion ellipsoid, respectively. For example, the eigenvalue corresponding to the eigenvector along the long axis of the fiber corresponds qualitatively to diffusion with least restriction. Determination of the principal values of the diffusion tensor and various anisotropic indices provides structural information. We review the use of diffusion measurements using the modified Stejskal-Tanner diffusion equation. The anisotropy is analyzed by decomposing the diffusion tensor based on symmetrical properties describing the geometry of diffusion tensor. We further describe diffusion tensor properties in visualizing fiber tract organization of the human brain.

  12. Subacute sclerosing panencephalitis with bilateral inferior collicular hyperintensity on magnetic resonance imaging brain

    Directory of Open Access Journals (Sweden)

    Maya Thomas

    2012-01-01

    Full Text Available Subacute sclerosing panencephalitis (SSPE is chronic encephalitis occurring after infection with measles virus. An 8-year-old boy presented with progressive behavioral changes, cognitive decline and myoclonic jerks, progressing to a bed bound state over 2 months. Magnetic resonance imaging (MRI brain showed T2-weighted hyperintensities in the subcortical areas of the left occipital lobe and brachium of the inferior colliculus on both sides. EEG showed bilateral, synchronous periodic discharges. Serum/cerebrospinal fluid measles IgG titer was significantly positive. The overall features were suggestive of SSPE. MRI finding of bilateral inferior colliculus changes on MRI without significant involvement of other commonly involved areas suggests an uncommon/rare imaging pattern of SSPE.

  13. Data of NODDI diffusion metrics in the brain and computer simulation of hybrid diffusion imaging (HYDI acquisition scheme

    Directory of Open Access Journals (Sweden)

    Chandana Kodiweera

    2016-06-01

    Full Text Available This article provides NODDI diffusion metrics in the brains of 52 healthy participants and computer simulation data to support compatibility of hybrid diffusion imaging (HYDI, “Hybrid diffusion imaging” [1] acquisition scheme in fitting neurite orientation dispersion and density imaging (NODDI model, “NODDI: practical in vivo neurite orientation dispersion and density imaging of the human brain” [2]. HYDI is an extremely versatile diffusion magnetic resonance imaging (dMRI technique that enables various analyzes methods using a single diffusion dataset. One of the diffusion data analysis methods is the NODDI computation, which models the brain tissue with three compartments: fast isotropic diffusion (e.g., cerebrospinal fluid, anisotropic hindered diffusion (e.g., extracellular space, and anisotropic restricted diffusion (e.g., intracellular space. The NODDI model produces microstructural metrics in the developing brain, aging brain or human brain with neurologic disorders. The first dataset provided here are the means and standard deviations of NODDI metrics in 48 white matter region-of-interest (ROI averaging across 52 healthy participants. The second dataset provided here is the computer simulation with initial conditions guided by the first dataset as inputs and gold standard for model fitting. The computer simulation data provide a direct comparison of NODDI indices computed from the HYDI acquisition [1] to the NODDI indices computed from the originally proposed acquisition [2]. These data are related to the accompanying research article “Age Effects and Sex Differences in Human Brain White Matter of Young to Middle-Aged Adults: A DTI, NODDI, and q-Space Study” [3].

  14. Grey and white matter changes in children with monocular amblyopia: voxel-based morphometry and diffusion tensor imaging study.

    Science.gov (United States)

    Li, Qian; Jiang, Qinying; Guo, Mingxia; Li, Qingji; Cai, Chunquan; Yin, Xiaohui

    2013-04-01

    To investigate the potential morphological alterations of grey and white matter in monocular amblyopic children using voxel-based morphometry (VBM) and diffusion tensor imaging (DTI). A total of 20 monocular amblyopic children and 20 age-matched controls were recruited. Whole-brain MRI scans were performed after a series of ophthalmologic exams. The imaging data were processed and two-sample t-tests were employed to identify group differences in grey matter volume (GMV), white matter volume (WMV) and fractional anisotropy (FA). After image screening, there were 12 amblyopic participants and 15 normal controls qualified for the VBM analyses. For DTI analysis, 14 amblyopes and 14 controls were included. Compared to the normal controls, reduced GMVs were observed in the left inferior occipital gyrus, the bilateral parahippocampal gyrus and the left supramarginal/postcentral gyrus in the monocular amblyopic group, with the lingual gyrus presenting augmented GMV. Meanwhile, WMVs reduced in the left calcarine, the bilateral inferior frontal and the right precuneus areas, and growth in the WMVs was seen in the right cuneus, right middle occipital and left orbital frontal areas. Diminished FA values in optic radiation and increased FA in the left middle occipital area and right precuneus were detected in amblyopic patients. In monocular amblyopia, cortices related to spatial vision underwent volume loss, which provided neuroanatomical evidence of stereoscopic defects. Additionally, white matter development was also hindered due to visual defects in amblyopes. Growth in the GMVs, WMVs and FA in the occipital lobe and precuneus may reflect a compensation effect by the unaffected eye in monocular amblyopia.

  15. Comparison of Magnetic Susceptibility Tensor and Diffusion Tensor of the Brain.

    Science.gov (United States)

    Li, Wei; Liu, Chunlei

    2013-10-01

    Susceptibility tensor imaging (STI) provides a novel approach for noninvasive assessment of the white matter pathways of the brain. Using mouse brain ex vivo , we compared STI with diffusion tensor imaging (DTI), in terms of tensor values, principal tensor values, anisotropy values, and tensor orientations. Despite the completely different biophysical underpinnings, magnetic susceptibility tensors and diffusion tensors show many similarities in the tensor and principal tensor images, for example, the tensors perpendicular to the fiber direction have the highest gray-white matter contrast, and the largest principal tensor is along the fiber direction. Comparison to DTI fractional anisotropy, the susceptibility anisotropy provides much higher sensitivity to the chemical composition of the white matter, especially myelin. The high sensitivity can be further enhanced with the perfusion of ProHance, a gadolinium-based contrast agent. Regarding the tensor orientations, the direction of the largest principal susceptibility tensor agrees with that of diffusion tensors in major white matter fiber bundles. The STI fiber tractography can reconstruct the fiber pathways for the whole corpus callosum and for white matter fiber bundles that are in close contact but in different orientations. There are some differences between susceptibility and diffusion tensor orientations, which are likely due to the limitations in the current STI reconstruction. With the development of more accurate reconstruction methods, STI holds the promise for probing the white matter micro-architectures with more anatomical details and higher chemical sensitivity.

  16. Effect of the Maximum Dose on White Matter Fiber Bundles Using Longitudinal Diffusion Tensor Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Tong; Chapman, Christopher H. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Tsien, Christina [Department of Radiation Oncology, Washington University at St Louis, St Louis, Missouri (United States); Kim, Michelle; Spratt, Daniel E.; Lawrence, Theodore S. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Cao, Yue, E-mail: yuecao@umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan (United States)

    2016-11-01

    Purpose: Previous efforts to decrease neurocognitive effects of radiation focused on sparing isolated cortical structures. We hypothesize that understanding temporal, spatial, and dosimetric patterns of radiation damage to whole-brain white matter (WM) after partial-brain irradiation might also be important. Therefore, we carried out a study to develop the methodology to assess radiation therapy (RT)–induced damage to whole-brain WM bundles. Methods and Materials: An atlas-based, automated WM tractography analysis was implemented to quantify longitudinal changes in indices of diffusion tensor imaging (DTI) of 22 major WM fibers in 33 patients with predominantly low-grade or benign brain tumors treated by RT. Six DTI scans per patient were performed from before RT to 18 months after RT. The DTI indices and planned doses (maximum and mean doses) were mapped onto profiles of each of 22 WM bundles. A multivariate linear regression was performed to determine the main dose effect as well as the influence of other clinical factors on longitudinal percentage changes in axial diffusivity (AD) and radial diffusivity (RD) from before RT. Results: Among 22 fiber bundles, AD or RD changes in 12 bundles were affected significantly by doses (P<.05), as the effect was progressive over time. In 9 elongated tracts, decreased AD or RD was significantly related to maximum doses received, consistent with a serial structure. In individual bundles, AD changes were up to 11.5% at the maximum dose locations 18 months after RT. The dose effect on WM was greater in older female patients than younger male patients. Conclusions: Our study demonstrates for the first time that the maximum dose to the elongated WM bundles causes post-RT damage in WM. Validation and correlative studies are necessary to determine the ability and impact of sparing these bundles on preserving neurocognitive function after RT.

  17. Cortical fibers orientation mapping using in-vivo whole brain 7 T diffusion MRI

    NARCIS (Netherlands)

    Gulban, Omer F; De Martino, Federico; Vu, An T; Yacoub, Essa; Uğurbil, Kamil; Lenglet, Christophe

    Diffusion MRI of the cortical gray matter is challenging because the micro-environment probed by water molecules is much more complex than within the white matter. High spatial and angular resolutions are therefore necessary to uncover anisotropic diffusion patterns and laminar structures, which

  18. Structural changes of central white matter tracts in Kennedy's disease - a diffusion tensor imaging and voxel-based morphometry study.

    Science.gov (United States)

    Pieper, C C; Konrad, C; Sommer, J; Teismann, I; Schiffbauer, H

    2013-05-01

    Spinobulbar muscular atrophy [Kennedy's disease (KD)] is a rare X-linked neurodegenerative disorder of mainly spinal and bulbar motoneurons. Recent studies suggest a multisystem character of this disease. The aim of this study was to identify and characterize structural changes of gray (GM) and white matter (WM) in the central nervous system. Whole-brain-based voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) analyses were applied to MRI data of eight genetically proven patients with KD and compared with 16 healthy age-matched controls. Diffusion tensor imaging analysis showed not only decreased fractional anisotropy (FA) values in the brainstem, but also widespread changes in central WM tracts, whereas VBM analysis of the WM showed alterations primarily in the brainstem and cerebellum. There were no changes in GM volume. The FA value decrease in the brainstem correlated with the disease duration. Diffusion tensor imaging analysis revealed subtle changes of central WM tract integrity, while GM and WM volume remained unaffected. In our patient sample, KD had more extended effects than previously reported. These changes could either be attributed primarily to neurodegeneration or reflect secondary plastic changes due to atrophy of lower motor neurons and reorganization of cortical structures. © 2012 John Wiley & Sons A/S.

  19. Multilevel Deficiency of White Matter Connectivity Networks in Alzheimer's Disease: A Diffusion MRI Study with DTI and HARDI Models.

    Science.gov (United States)

    Wang, Tao; Shi, Feng; Jin, Yan; Yap, Pew-Thian; Wee, Chong-Yaw; Zhang, Jianye; Yang, Cece; Li, Xia; Xiao, Shifu; Shen, Dinggang

    2016-01-01

    Alzheimer's disease (AD) is the most common form of dementia in elderly people. It is an irreversible and progressive brain disease. In this paper, we utilized diffusion-weighted imaging (DWI) to detect abnormal topological organization of white matter (WM) structural networks. We compared the differences between WM connectivity characteristics at global, regional, and local levels in 26 patients with probable AD and 16 normal control (NC) elderly subjects, using connectivity networks constructed with the diffusion tensor imaging (DTI) model and the high angular resolution diffusion imaging (HARDI) model, respectively. At the global level, we found that the WM structural networks of both AD and NC groups had a small-world topology; however, the AD group showed a significant decrease in both global and local efficiency, but an increase in clustering coefficient and the average shortest path length. We further found that the AD patients had significantly decreased nodal efficiency at the regional level, as well as weaker connections in multiple local cortical and subcortical regions, such as precuneus, temporal lobe, hippocampus, and thalamus. The HARDI model was found to be more advantageous than the DTI model, as it was more sensitive to the deficiencies in AD at all of the three levels.

  20. Case report of a young stroke patient showing interim normalization of the MRI diffusion-weighted imaging lesion

    International Nuclear Information System (INIS)

    Ostwaldt, Ann-Christin; Usnich, Tatiana; Nolte, Christian H.; Villringer, Kersten; Fiebach, Jochen B.

    2015-01-01

    In acute ischemic stroke, diffusion weighted imaging (DWI) shows hyperintensities and is considered to indicate irreversibly damaged tissue. We present the case of a young stroke patient with unusual variability in the development of signal intensities within the same vessel territory. A 35-year-old patient presented with symptoms of global aphasia and hypesthesia of the left hand. MRI demonstrated a scattered lesion in the MCA territory. After rtPA therapy the patient received further MRI examination, three times on day 1, and once on day 2, 3, 5 and 43. The posterior part of the lesion showed the usual pattern with increasing DWI hyperintensity and decreased ADC, as well as delayed FLAIR positivity. However, the anterior part of the lesion, which was clearly visible in the first examination completely normalized on the first day and only reappeared on day 2. This was accompanied by a normalization of the ADC as well as an even further delayed FLAIR positivity. We showed that interim normalization of DWI and ADC in the acute phase can not only be found in rodent models of stroke, but also in humans. We propose that DWI lesion development might be more variable during the first 24 h after stroke than previously assumed

  1. Neutrino diffusion and mass ejection in protoneutron stars

    International Nuclear Information System (INIS)

    Almeida, L. G.; Rodrigues, H.; Portes, D. Jr.; Duarte, S. B.

    2010-01-01

    We discuss the mass ejection mechanism induced by diffusion of neutrino during the early stage of the protoneutron star cooling. A dynamical calculation is employed in order to determine the amount of matter ejected and the remnant compact object mass. An equation of state considering hadronic and quark phases for the stellar dense matter was used to solve the whole time evolution of the system during the cooling phase. The initial neutrino population was obtained by considering beta equilibrium in the dense stellar matter with confined neutrinos, in the very early period of the deleptonic stage of the nascent pulsar. For specified initial configurations of the protoneutron star, we solve numerically the set of equations of motion together with neutrino diffusion through the dense stellar medium.

  2. Now consider diffusion

    International Nuclear Information System (INIS)

    Dungey, J.W.

    1984-01-01

    The authors want to talk about future work, but first he will reply to Stan Cowley's comment on his naivety in believing in the whole story to 99% confidence in '65, when he knew about Fairfield's results. Does it matter whether you make the right judgment about theories? Yes, it does, particularly for experimentalists perhaps, but also for theorists. The work you do later depends on the judgment you've made on previous work. People have wasted a lot of time developing on insecure or even wrong foundations. Now for future work. One mild surprise the authors have had is that they haven't heard more about diffusion, in two contexts. Gordon Rostoker is yet to come and he may talk about particles getting into the magnetosphere by diffusion. Lots of noise is observed and so diffusion must happen. If time had not been short, the authors were planning to discuss in a handwaving way what sort of diffusion mechanisms one might consider. The other aspect of diffusion he was going to talk about is at the other end of things and is velocity diffusion, which is involved in anomalous resistivity

  3. Hepatocellular carcinoma on MR diffusion weighted imaging and dynamic contrast-enhanced imaging

    International Nuclear Information System (INIS)

    Dong Aisheng; Zuo Changjing; Tian Jianming; Lu Jianping; Wang Jian; Wang Li; Wang Fei

    2009-01-01

    Objective: To evaluate the findings of hepatocellular carcinoma (HCC) on DWI and dynamic Gd-DTPA-enhanced MR imaging. Methods: Eighty one patients with chronic hepatitis or liver cirrhosis underwent both DWI and dynamic Gd-DTPA-enhanced MRI studies of the liver for HCC detection. MR data of were retrospectively analyzed. Two observers determined in consensus the location and the number of focal lesions. The signal manifestation of the lesions on DWI and dynamic Gd-DTPA-enhanced MR imaging were analyzed. Results: DWI and Gd-DTPA-enhanced MR images detected 122 HCCs and 14 benign lesions. One hundred and sixteen HCCs (95.1%) showed hyperintensity on DWI and 6 HCCs in patients with severe cirrhosis showed isointensity. One hundred and five HCCs (86.1%) revealed hypointensity, 11 HCCs (9.0%) showed isointensity and 6 HCCs (4.9%) exhibited hyperintensity on T 1 weighted images. On Gd-DTPA-enhanced MR images, 101 HCCs(82.8%) were significantly enhanced on arterial phase and 99 HCCs showed hypointensity on portal and equilibrium phases. Twenty HCCs (16.4%), 18 of 20 less than 20 mm in diameter, showed isointensity on arterial phase and hyperintensity on DWI. Eight of 14 benign lesions showed hyperintensity and 6 isointensity on DWI. Five benign lesions with hypointensity on T 1 weighted images without contrast and hyperintensity on DWI showed no enhancement on Gd-DTPA-enhanced MR images; 6 benign lesions with isointensity on both T 1 weighted imaging without contrast and DWI exhibited avid enhancement on arterial phase and isointensty on portal and equilibrium phases; one of the two benign lesions, with isointensity before and after contrast images and hyperintentiy on DWI, was a regenerative nodule; another regenerative nodule with hyperintensity on both T 1 weighted images without contrast and DWI was greatly enhanced on arterial phase and showed isointensity on portal and equilibrium phases. Conclusions: Most of the HCCs were greatly enhanced on arterial phase on Gd

  4. Soft matter in hard confinement: phase transition thermodynamics, structure, texture, diffusion and flow in nanoporous media

    Science.gov (United States)

    Huber, Patrick

    2015-03-01

    Spatial confinement in nanoporous media affects the structure, thermodynamics and mobility of molecular soft matter often markedly. This article reviews thermodynamic equilibrium phenomena, such as physisorption, capillary condensation, crystallisation, self-diffusion, and structural phase transitions as well as selected aspects of the emerging field of spatially confined, non-equilibrium physics, i.e. the rheology of liquids, capillarity-driven flow phenomena, and imbibition front broadening in nanoporous materials. The observations in the nanoscale systems are related to the corresponding bulk phenomenologies. The complexity of the confined molecular species is varied from simple building blocks, like noble gas atoms, normal alkanes and alcohols to liquid crystals, polymers, ionic liquids, proteins and water. Mostly, experiments with mesoporous solids of alumina, gold, carbon, silica, and silicon with pore diameters ranging from a few up to 50 nm are presented. The observed peculiarities of nanopore-confined condensed matter are also discussed with regard to applications. A particular emphasis is put on texture formation upon crystallisation in nanoporous media, a topic both of high fundamental interest and of increasing nanotechnological importance, e.g. for the synthesis of organic/inorganic hybrid materials by melt infiltration, the usage of nanoporous solids in crystal nucleation or in template-assisted electrochemical deposition of nano structures.

  5. Automated detection of Lupus white matter lesions in MRI

    Directory of Open Access Journals (Sweden)

    Eloy Roura Perez

    2016-08-01

    Full Text Available Brain magnetic resonance imaging provides detailed information which can be used to detect and segment white matter lesions (WML. In this work we propose an approach to automatically segment WML in Lupus patients by using T1w and fluid-attenuated inversion recovery (FLAIR images. Lupus WML appear as small focal abnormal tissue observed as hyperintensities in the FLAIR images. The quantification of these WML is a key factor for the stratification of lupus patients and therefore both lesion detection and segmentation play an important role. In our approach, the T1w image is first used to classify the three main tissues of the brain, white matter (WM, gray matter (GM and cerebrospinal fluid (CSF, while the FLAIR image is then used to detect focal WML as outliers of its GM intensity distribution. A set of post-processing steps based on lesion size, tissue neighborhood, and location are used to refine the lesion candidates. The proposal is evaluated on 20 patients, presenting qualitative and quantitative results in terms of precision and sensitivity of lesion detection (True Positive Rate (62% and Positive Prediction Value (80% respectively as well as segmentation accuracy (Dice Similarity Coefficient (72%. Obtained results illustrate the validity of the approach to automatically detect and segment lupus lesions. Besides, our approach is publicly available as a SPM8/12 toolbox extension with a simple parameter configuration.

  6. Dynamics of the diffusive DM-DE interaction – Dynamical system approach

    Energy Technology Data Exchange (ETDEWEB)

    Haba, Zbigniew [Institute of Theoretical Physics, University of Wroclaw, Plac Maxa Borna 9, 50-204 Wrocław (Poland); Stachowski, Aleksander; Szydłowski, Marek, E-mail: zhab@ift.uni.wroc.pl, E-mail: aleksander.stachowski@uj.edu.pl, E-mail: marek.szydlowski@uj.edu.pl [Astronomical Observatory, Jagiellonian University, Orla 171, 30-244 Krakow (Poland)

    2016-07-01

    We discuss dynamics of a model of an energy transfer between dark energy (DE) and dark matter (DM) . The energy transfer is determined by a non-conservation law resulting from a diffusion of dark matter in an environment of dark energy. The relativistic invariance defines the diffusion in a unique way. The system can contain baryonic matter and radiation which do not interact with the dark sector. We treat the Friedman equation and the conservation laws as a closed dynamical system. The dynamics of the model is examined using the dynamical systems methods for demonstration how solutions depend on initial conditions. We also fit the model parameters using astronomical observation: SNIa, H ( z ), BAO and Alcock-Paczynski test. We show that the model with diffuse DM-DE is consistent with the data.

  7. Diffusion or bulk flow

    DEFF Research Database (Denmark)

    Schulz, Alexander

    2015-01-01

    is currently matter of discussion, called passive symplasmic loading. Based on the limited material available, this review compares the different loading modes and suggests that diffusion is the driving force in apoplasmic loaders, while bulk flow plays an increasing role in plants having a continuous...

  8. Hyperintense basal ganglia lesions on T1-weighted MR images in asymptomatic patients with hepatic dysfunction

    Energy Technology Data Exchange (ETDEWEB)

    Saatci, I. [Dept. of Radiology, Hacettepe Univ. Hospital, Ankara (Turkey); Cila, A. [Dept. of Radiology, Hacettepe Univ. Hospital, Ankara (Turkey); Dincer, F.F. [Dept. of Radiology, Hacettepe Univ. Hospital, Ankara (Turkey)

    1995-12-31

    Cranial MRI findings in four patients who had hepatic dysfunction, including one with sole hepatic form of Wilson`s disease, were reported. The MR examinations revealed bilateral, symmetric hyperintensity in the globus pallidus, subthalamic nuclei and mesencephalon on T1-weighted images with no corresponding abnormality on T2-weighted sequences. The basal ganglia were normal on CT examinations in all patients. None of the patients had the clinical findings of hepatic encephalopathy. The MR findings in our patients did not correlate with the degree or duration of hepatic dysfunction. (orig.)

  9. White and gray matter abnormalities in idiopathic rapid eye movement sleep behavior disorder: a diffusion-tensor imaging and voxel-based morphometry study.

    Science.gov (United States)

    Scherfler, Christoph; Frauscher, Birgit; Schocke, Michael; Iranzo, Alex; Gschliesser, Viola; Seppi, Klaus; Santamaria, Joan; Tolosa, Eduardo; Högl, Birgit; Poewe, Werner

    2011-02-01

    We applied diffusion-tensor imaging (DTI) including measurements of mean diffusivity (MD), a parameter of brain tissue integrity, fractional anisotropy (FA), a parameter of neuronal fiber integrity, as well as voxel-based morphometry (VBM), a measure of gray and white matter volume, to detect brain tissue changes in patients with idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD). Magnetic resonance imaging (MRI) was performed in 26 patients with iRBD (mean disease duration, 9.2 ± 6.4 years) and 14 age-matched healthy control subjects. Statistical parametric mapping (SPM) was applied to objectively identify focal changes of MRI parameters throughout the entire brain volume. SPM localized significant decreases of FA in the tegmentum of the midbrain and rostral pons and increases of MD within the pontine reticular formation overlapping with a cluster of decreased FA in the midbrain (p < 0.001). VBM revealed increases of gray matter densities in both hippocampi of iRBD patients (p < 0.001). The observed changes in the pontomesencephalic brainstem localized 2 areas harboring key neuronal circuits believed to be involved in the regulation of REM sleep and overlap with areas of structural brainstem damage causing symptomatic RBD in humans. Bilateral increases in gray matter density of the hippocampus suggest functional neuronal reorganization in this brain area in iRBD. This study indicates that DTI detects distinct structural brainstem tissue abnormalities in iRBD in the regions where REM is modulated. Further studies should explore the relationship between MRI pathology and the risk of patients with iRBD of developing alpha-synuclein-related neurodegenerative diseases like Parkinson disease. Copyright © 2010 American Neurological Association.

  10. Diffusion tensor imaging of the brainstem in children with achondroplasia.

    Science.gov (United States)

    Bosemani, Thangamadhan; Orman, Gunes; Carson, Kathryn A; Meoded, Avner; Huisman, Thierry A G M; Poretti, Andrea

    2014-11-01

    The aims of this study were to compare, using diffusion tensor imaging (DTI) of the brainstem, microstructural integrity of the white matter in children with achondroplasia and age-matched participants and to correlate the severity of craniocervical junction (CCJ) narrowing and neurological findings with DTI scalars in children with achondroplasia. This study also aimed to assess the potential role of fibroblast growth factor receptor type 3 on white matter microstructure. Diffusion tensor imaging was performed using a 1.5T magnetic resonance scanner and balanced pairs of diffusion gradients along 20 non-collinear directions. Measurements were obtained from regions of interest, sampled in each pontine corticospinal tract (CST), medial lemniscus, and middle cerebellar peduncle, as well as in the lower brainstem and centrum semiovale, for fractional anisotropy and for mean, axial, and radial diffusivity. In addition, a severity score for achondroplasia was assessed by measuring CCJ narrowing. Eight patients with achondroplasia (seven males, one female; mean age 5y 6mo, range 1y 1mo-15y 1mo) and eight age- and sex-matched comparison participants (mean age 5y 2mo, range 1y 1mo-14y 11mo) were included in this study. Fractional anisotropy was lower and mean diffusivity and radial diffusivity were higher in the lower brainstem of patients with achondroplasia than in age-matched comparison participants. The CST and middle cerebellar peduncle of the participants showed increases in mean, axial, and radial diffusivity. Fractional anisotropy in the lower brainstem was negatively correlated with the degree of CCJ narrowing. No differences in the DTI metrics of the centrum semiovale were observed between the two groups. The reduction in fractional anisotropy and increase in diffusivities in the lower brainstem of participants with achondroplasia may reflect secondary encephalomalacic degeneration and cavitation of the affected white matter tracts as shown by histology. In

  11. Brain white matter damage in aging and cognitive ability in youth and older age☆

    Science.gov (United States)

    Valdés Hernández, Maria del C.; Booth, Tom; Murray, Catherine; Gow, Alan J.; Penke, Lars; Morris, Zoe; Maniega, Susana Muñoz; Royle, Natalie A.; Aribisala, Benjamin S.; Bastin, Mark E.; Starr, John M.; Deary, Ian J.; Wardlaw, Joanna M.

    2013-01-01

    Cerebral white matter hyperintensities (WMH) reflect accumulating white matter damage with aging and impair cognition. The role of childhood intelligence is rarely considered in associations between cognitive impairment and WMH. We studied community-dwelling older people all born in 1936, in whom IQ had been assessed at age 11 years. We assessed medical histories, current cognitive ability and quantified WMH on MR imaging. Among 634 participants, mean age 72.7 (SD 0.7), age 11 IQ was the strongest predictor of late life cognitive ability. After accounting for age 11 IQ, greater WMH load was significantly associated with lower late life general cognitive ability (β = −0.14, p cognitive ability, after accounting for prior ability, age 11IQ. Early-life IQ also influenced WMH in later life. Determining how lower IQ in youth leads to increasing brain damage with aging is important for future successful cognitive aging. PMID:23850341

  12. Mild encephalopathy with a reversible splenial lesion in a girl with acute pyelonephritis.

    Science.gov (United States)

    Yeom, Jung Sook; Koo, Chung Mo; Park, Ji Sook; Seo, Ji-Hyun; Park, Eun Sil; Lim, Jae-Young; Woo, Hyang-Ok; Youn, Hee-Shang

    2018-02-01

    We report the case of a 12-year-old girl who had mild encephalopathy with a reversible splenial lesion (MERS) associated with acutepyelonephritis caused by Escherichia coli . The patient was admitted with a high fever, and she was diagnosed with acute pyelonephritis based on pyuria and the results of urine culture, which detected cefotaxime-sensitive E. coli . Although intravenous cefotaxime and tobramycin were administered, her fever persisted and her C-reactive protein level increased to 307 mg/L. On day 3 of admission, she demonstrated abnormal neuropsychiatric symptoms, such as delirium, ataxia, and word salad. Magnetic resonance imaging (MRI) of the brain performed on day 4 showed marked hyperintensities in the bilateral corpus callosum and deep white matter on diffusion-weighted images, with corresponding diffusion restriction on apparent diffusion coefficient mapping. No abnormalities or pathogens were detected in the cerebrospinal fluid; however, lipopolysaccharides (LPS, endotoxin) were detected in plasma (41.6 pg/mL), associated with acute neurological deterioration. Her clinical condition gradually improved, and no neurological abnormalities were observed on day 6. Follow-up brain MRI performed 2 weeks later showed near-disappearance of the previously noted hyperintense lesions. In this patient, we first proved endotoxemia in a setting of MERS. The release of LPS following antibiotic administration might be related to the development of MERS in this patient. The possibility of MERS should be considered in patients who present with acute pyelonephritis and demonstrate delirious behavior.

  13. Diffusion-weighted MR imaging in the early diagnosis of periventricular leukomalacia

    International Nuclear Information System (INIS)

    Bozzao, Alessandro; Di Paolo, Ambrogio; Simonetti, Alessandra; Mazzoleni, Clarissa; Fasoli, Fabrizio; Floris, Roberto; Fantozzi, Luigi Maria

    2003-01-01

    Diffusion-weighted imaging (DWI) has been shown to be highly sensitive in detecting acute cerebral infarction, but its use in detecting hypoxic-ischemic encephalopathy (HIE) in neonates is still controversial. Moreover, few reports concern pre-term infants with possible periventricular leukomalacia (PVL). We examined the ability of this technique to detect cerebral changes in the acute phase of PVL. Fifteen MR examinations were performed in 11 pre-term infants (mean age 3.4 days, range 2-6 days). Conventional DWI sequences, apparent diffusion coefficient (ADC) maps, and US obtained in the acute phase were compared. All the neonates underwent US follow-up up to 4 months after delivery; those with suspected PVL also underwent MRI follow-up for up to 2 months. Qualitative and quantitative evaluations were performed to assess the presence of DW changes compatible with PVL. Diffusion-weighted MRI showed signal hyperintensity associated with decreased ADC values in 3 subjects (27%). In these patients conventional MRI sequences were interpreted as normal and US (performed at the same time) as doubtful in 2 and compatible with PVL in 1 subject. The MRI and US follow-up confirmed severe damage in all these patients. In 1 neonate hemorrhages involving the germinative matrix were identified. In 8 neonates MRI was considered normal. In these subjects US follow-up (up to 4 months) confirmed no signs of PVL. Diffusion-weighted imaging may have a higher correlation with later evidence of PVL than does conventional MR imaging and US when performed in the acute phase of the disease. (orig.)

  14. Diffusion formation and psychiatric diseases

    International Nuclear Information System (INIS)

    Reith, W.; Kulikovski, J.

    2015-01-01

    The basic principle behind diffusion is Brownian motion. The diffusion parameters obtained in a clinical association provide information on the spatial distribution of water molecule mobility and, therefore, evidence of the morphological integrity of the white and grey matters of the brain. In recent years functional magnetic resonance imaging (fMRI) could contribute to obtaining a detailed understanding of the cortical and subcortical cerebral networks. Diffusion tensor imaging (DTI) investigations can demonstrate the extent of anisotropy and the fiber pathways in so-called parametric images. For example, in Alzheimer's disease DTI reveals a reduced structural connectivity between the posterior cingulum and the hippocampus. This article shows examples of the application of diffusion-weighted imaging (DWI) in psychiatric disorders. (orig.) [de

  15. Common late-onset subcortical cerebral hemorrhage following excessive alcohol consumption: a case report

    International Nuclear Information System (INIS)

    Incedayi, M.; Sivrioglu, A.; Velioglu, M.; Aribal, S.; Sonmez, G.; Basekim, C.

    2012-01-01

    Full text: 50 year old male patient who was suffering from cooperation disorder and bilaterally blindness was admitted to our emergency service. He was addicted to alcohol and had excessive alcohol consumption the day before. Cranial nonenhanced CT was normal. T2 weighed MR imaging performed at 1,5 T unit showed high signal intensity in bilateral putaminal foci. In this localization diffusion-weighed images (DWI) were hyperintense due to restricted diffusion and low ADC values. After two weeks, drowsiness and confusion were appeared suddenly. Cranial nonenhanced CT was showed extensive subcortical white matter and basal ganglia abnormalities consistent with edema and hemorrhagic changes. The patient was transferred to intensive care unit and died after one day. In methanol intoxication, cerebral and intraventricular hemorrhage, cerebellar necrosis, diffuse cerebral edema, bilateral subcortical white matter necrosis and edema were defined It should also be known that 2 or 3 weeks after ingestion of methyl alcohol, the deterioration of the patient's general situation is responsible for cerebral subcortical hemorrhage. We have also thought that patients' mortality and morbidity can be reduced with radiological imaging due to early diagnosis

  16. Diffusion tensor imaging of occult injury of optic radiation following optic neuritis in multiple sclerosis.

    Science.gov (United States)

    Chen, Jiafeng; Zhu, Lijun; Li, He; Lu, Ziwen; Chen, Xin; Fang, Shaokuan

    2016-10-01

    Multiple sclerosis (MS) is easily detected by routine magnetic resonance imaging (MRI). However, it is not possible to detect early or occult lesions in MS by routine MRI, and this may explain the inconsistency between the severity of the lesions found by MRI and the degree of clinical disability of patients with MS. The present study included 10 patients with relapsing-remitting MS and 10 healthy volunteers. Each patient underwent routine 3.0 T MRI, diffusion tensor imaging (DTI), and diffusion tensor tractography (DTT). Optic nerve and optic radiation were analyzed by DTI and DTT. The fractional anisotropy (FA), mean diffusivity (MD), λ // , and λ ┴ values were measured. In the 10 patients with MS, 7 optic nerves were affected, and 13 optic nerves were not affected. Cranial MRI showed that optic nerve thickening and hyperintensity occurred in 2 patients with MS. In the directionally encoded color maps, a hypointensive green signal in the optic nerve was observed in 3 patients with MS. The FA values were significantly lower and the MD, λ // , and λ ┴ values were significantly higher in the affected and unaffected optic nerves and optic radiations in patients with MS in comparison with controls (P0.05). Diffusion tensor imaging is sensitive in the detection of occult injury of the optic nerve and optic radiation following optic neuritis. Diffusion tensor imaging may be a useful tool for the early diagnosis, treatment and management of MS.

  17. MR diffusion tensor analysis of schizophrenic brain using statistical parametric mapping

    International Nuclear Information System (INIS)

    Yamada, Haruyasu; Abe, Osamu; Kasai, Kiyoto

    2005-01-01

    The purpose of this study is to investigate diffusion anisotropy in the schizophrenic brain by voxel-based analysis of diffusion tensor imaging (DTI), using statistical parametric mapping (SPM). We studied 33 patients with schizophrenia diagnosed by diagnostic and statistical manual of mental disorders (DSM)-IV criteria and 42 matched controls. The data was obtained with a 1.5 T MRI system. We used single-shot spin-echo planar sequences (repetition time/echo time (TR/TE)=5000/102 ms, 5 mm slice thickness and 1.5 mm gap, field of view (FOV)=21 x 21 cm 2 , number of excitation (NEX)=4, 128 x 128 pixel matrix) for diffusion tensor acquisition. Diffusion gradients (b-value of 500 or 1000 s/mm 2 ) were applied on two axes simultaneously. Diffusion properties were measured along 6 non-linear directions. The structural distortion induced by the large diffusion gradients was corrected, based on each T 2 -weighted echo-planar image (b=0 s/mm 2 ). The fractional anisotropy (FA) maps were generated on a voxel-by-voxel basis. T 2 -weighted echo-planar images were then segmented into gray matter, white matter, and cerebrospinal fluid, using SPM (Wellcome Department of Imaging, University College London, UK). All apparent diffusion coefficient (ADC) and FA maps in native space were transformed to the stereotactic space by registering each of the images to the same template image. The normalized data was smoothed and analyzed using SPM. The significant FA decrease in the patient group was found in the uncinate fasciculus, parahippocampal white matter, anterior cingulum and other areas (corrected p<0.05). No significant increased region was noted. Our results may reflect reduced diffusion anisotropy of the white matter pathway of the limbic system as shown by the decreased FA. Manual region-of-interest analysis is usually more sensitive than voxel-based analysis, but it is subjective and difficult to set with anatomical reproducibility. Voxel-based analysis of the diffusion tensor

  18. Dark matter implications of Fermi-LAT measurement of anisotropies in the diffuse gamma-ray background

    International Nuclear Information System (INIS)

    Gómez-Vargas, G.A.; Cuoco, A.; Linden, T.; Sánchez-Conde, M.A.; Siegal-Gaskins, J.M.; Delahaye, T.; Fornasa, M.; Komatsu, E.

    2014-01-01

    The detailed origin of the diffuse gamma-ray background is still unknown. However, the contribution of unresolved sources is expected to induce small-scale anisotropies in this emission, which may provide a way to identify and constrain the properties of its contributors. Recent studies have predicted the contributions to the angular power spectrum (APS) from extragalactic and galactic dark matter (DM) annihilation or decay. The Fermi-LAT collaboration reported detection of angular power with a significance larger than 3σ in the energy range from 1 GeV to 10 GeV on 22 months of data (Ackermann et al., 2012 [2]). For these preliminary results the already published Fermi-LAT APS measurements (Ackermann et al., 2012 [2]) are compared to the accurate predictions for DM anisotropies from state-of-the-art cosmological simulations as presented in Fornasa et al. (2013) [1] to derive constraints on different DM candidates

  19. Dark matter implications of Fermi-LAT measurement of anisotropies in the diffuse gamma-ray background

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-Vargas, G.A., E-mail: germanarturo.gomez@uam.es [Departamento de Física Teórica, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Instituto de Física Teórica IFT-UAM/CSIC, Universidad Autónoma de Madrid, Cantoblanco, E-28049, Madrid (Spain); Istituto Nazionale di Fisica Nucleare, Sez. Roma Tor Vergata, Roma (Italy); Cuoco, A. [The Oskar Klein Centre for Cosmo Particle Physics, AlbaNova, SE-106 91 Stockholm (Sweden); Linden, T. [Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Sánchez-Conde, M.A. [SLAC National Accelerator Laboratory and Kavli Institute for Particle Astrophysics and Cosmology, Menlo Park, CA 94025 (United States); Siegal-Gaskins, J.M. [California Institute of Technology, Pasadena, CA 91125 (United States); Delahaye, T. [LAPTh, Universit e de Savoie, CNRS, 9 chemin de Bellevue, BP110, F-74941 Annecy-le-Vieux Cedex (France); Institut d' Astrophysique de Paris, UMR 7095 – CNRS, Universit e Pierre and Marie Curie, 98 bis boulevard Arago, 75014 Paris (France); Instituto de Física Teórica IFT-UAM/CSIC, Universidad Autónoma de Madrid, Cantoblanco, E-28049, Madrid (Spain); Fornasa, M. [School of Physics and Astronomy, University of Nottingham, NG7 2RD Nottingham (United Kingdom); Komatsu, E. [Max-Planck-Institut fur Astrophysik, Karl-Schwarzschild Str. 1, 85741 Garching (Germany); Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), Todai Institutes for Advanced Study, the University of Tokyo, Kashiwa 277-8583 (Japan); Texas Cosmology Center and the Department of Astronomy, The University of Texas at Austin, 1 University Station, C1400, Austin, TX 78712 (United States); and others

    2014-04-01

    The detailed origin of the diffuse gamma-ray background is still unknown. However, the contribution of unresolved sources is expected to induce small-scale anisotropies in this emission, which may provide a way to identify and constrain the properties of its contributors. Recent studies have predicted the contributions to the angular power spectrum (APS) from extragalactic and galactic dark matter (DM) annihilation or decay. The Fermi-LAT collaboration reported detection of angular power with a significance larger than 3σ in the energy range from 1 GeV to 10 GeV on 22 months of data (Ackermann et al., 2012 [2]). For these preliminary results the already published Fermi-LAT APS measurements (Ackermann et al., 2012 [2]) are compared to the accurate predictions for DM anisotropies from state-of-the-art cosmological simulations as presented in Fornasa et al. (2013) [1] to derive constraints on different DM candidates.

  20. Numerical simulation model of hyperacute/acute stage white matter infarction.

    Science.gov (United States)

    Sakai, Koji; Yamada, Kei; Oouchi, Hiroyuki; Nishimura, Tsunehiko

    2008-01-01

    Although previous studies have revealed the mechanisms of changes in diffusivity (apparent diffusion coefficient [ADC]) in acute brain infarction, changes in diffusion anisotropy (fractional anisotropy [FA]) in white matter have not been examined. We hypothesized that membrane permeability as well as axonal swelling play important roles, and we therefore constructed a simulation model using random walk simulation to replicate the diffusion of water molecules. We implemented a numerical diffusion simulation model of normal and infarcted human brains using C++ language. We constructed this 2-pool model using simple tubes aligned in a single direction. Random walk simulation diffused water. Axon diameters and membrane permeability were then altered in step-wise fashion. To estimate the effects of axonal swelling, axon diameters were changed from 6 to 10 microm. Membrane permeability was altered from 0% to 40%. Finally, both elements were combined to explain increasing FA in the hyperacute stage of white matter infarction. The simulation demonstrated that simple water shift into the intracellular space reduces ADC and increases FA, but not to the extent expected from actual human cases (ADC approximately 50%; FA approximately +20%). Similarly, membrane permeability alone was insufficient to explain this phenomenon. However, a combination of both factors successfully replicated changes in diffusivity indices. Both axonal swelling and reduced membrane permeability appear important in explaining changes in ADC and FA based on eigenvalues in hyperacute-stage white matter infarction.

  1. Diffusion-weighted MR imaging in leukodystrophies

    Energy Technology Data Exchange (ETDEWEB)

    Patay, Zoltan [King Faisal Specialist Hospital and Research Centre, Department of Radiology, Riyadh (Saudi Arabia)

    2005-11-01

    Leukodystrophies are genetically determined metabolic diseases, in which the underlying biochemical abnormality interferes with the normal build-up and/or maintenance of myelin, which leads to hypo- (or arrested) myelination, or dysmyelination with resultant demyelination. Although conventional magnetic resonance imaging has significantly contributed to recent progress in the diagnostic work-up of these diseases, diffusion-weighted imaging has the potential to further improve our understanding of underlying pathological processes and their dynamics through the assessment of normal and abnormal diffusion properties of cerebral white matter. Evaluation of conventional diffusion-weighted and ADC map images allows the detection of major diffusion abnormalities and the identification of various edema types, of which the so-called myelin edema is particularly relevant to leukodystrophies. Depending on the nature of histopathological changes, stage and progression gradient of diseases, various diffusion-weighted imaging patterns may be seen in leukodystrophies. Absent or low-grade myelin edema is found in mucopolysaccharidoses, GM gangliosidoses, Zellweger disease, adrenomyeloneuropathy, L-2-hydroxyglutaric aciduria, non-ketotic hyperglycinemia, classical phenylketonuria, Van der Knaap disease and the vanishing white matter, medium grade myelin edema in metachromatic leukodystrophy, X-linked adrenoleukodystrophy and HMG coenzyme lyase deficiency and high grade edema in Krabbe disease, Canavan disease, hyperhomocystinemias, maple syrup urine disease and leukodystrophy with brainstem and spinal cord involvement and high lactate. (orig.)

  2. Diffusion-weighted MR imaging in leukodystrophies

    International Nuclear Information System (INIS)

    Patay, Zoltan

    2005-01-01

    Leukodystrophies are genetically determined metabolic diseases, in which the underlying biochemical abnormality interferes with the normal build-up and/or maintenance of myelin, which leads to hypo- (or arrested) myelination, or dysmyelination with resultant demyelination. Although conventional magnetic resonance imaging has significantly contributed to recent progress in the diagnostic work-up of these diseases, diffusion-weighted imaging has the potential to further improve our understanding of underlying pathological processes and their dynamics through the assessment of normal and abnormal diffusion properties of cerebral white matter. Evaluation of conventional diffusion-weighted and ADC map images allows the detection of major diffusion abnormalities and the identification of various edema types, of which the so-called myelin edema is particularly relevant to leukodystrophies. Depending on the nature of histopathological changes, stage and progression gradient of diseases, various diffusion-weighted imaging patterns may be seen in leukodystrophies. Absent or low-grade myelin edema is found in mucopolysaccharidoses, GM gangliosidoses, Zellweger disease, adrenomyeloneuropathy, L-2-hydroxyglutaric aciduria, non-ketotic hyperglycinemia, classical phenylketonuria, Van der Knaap disease and the vanishing white matter, medium grade myelin edema in metachromatic leukodystrophy, X-linked adrenoleukodystrophy and HMG coenzyme lyase deficiency and high grade edema in Krabbe disease, Canavan disease, hyperhomocystinemias, maple syrup urine disease and leukodystrophy with brainstem and spinal cord involvement and high lactate. (orig.)

  3. Cognitive deficits are associated with frontal and temporal lobe white matter lesions in middle-aged adults living in the community.

    Directory of Open Access Journals (Sweden)

    David Bunce

    Full Text Available BACKGROUND: The association between brain white matter lesions and cognitive impairment in old age is well established. However, little is known about this association in midlife. As this information will inform policy for early preventative healthcare initiatives, we investigated non-periventricular frontal, temporal, parietal and occipital lobe white matter hyperintensities (WMH in relation to cognitive function in 428 (232 women community-dwelling adults aged 44 to 48 years. RESULTS: Frontal white matter lesions were significantly associated with greater intraindividual RT variability in women, while temporal WMH were associated with face recognition deficits in men. Parietal and occipital lobe lesions were unrelated to cognitive performance. These findings did not differ when education and a range of health variables, including vascular risk factors, were taken into account. CONCLUSION: Gender differences in WMH-cognition associations are discussed, and we conclude that small vessel disease is present in midlife and has functional consequences which are generally not recognized. Preventative strategies should, therefore, begin early in life.

  4. IgG4-related kidney disease: MRI findings with emphasis on the usefulness of diffusion-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bohyun; Kim, Jin Hee, E-mail: kimjhrad@amc.seoul.kr; Byun, Jae Ho; Kim, Hyoung Jung; Lee, Seung Soo; Kim, So Yeon; Lee, Moon-Gyu

    2014-07-15

    Objectives: To investigate the imaging findings of immunoglobulin G4 (IgG4)-related kidney disease (IgG4-KD) on magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI) and to evaluate the usefulness of DWI in lesion detection. Methods: This retrospective cohort study included 31 patients with IgG4-KD who underwent MRI covering both kidneys. Two radiologists reviewed in consensus the MR images to determine the distribution pattern (location, laterality, and multiplicity) and the visually assessed signal intensity (hypointense, isointense or hyperintense) of the renal lesions compared to the normal renal parenchyma on each sequence. Per-patient sensitivity for detecting IgG4-KD and the number of detectable lesions were compared in T2-weighted images, DWI, and dynamic contrast-enhanced images. Results: IgG4-KD typically manifested as bilateral (83.9%), multiple (93.5%), and renal parenchymal (87.1%) nodules appearing isointense (93.5%) on T1-weighted images, hypointense (77.4%) on T2-weighted images, hyperintense (100%) on DWI (b = 1000), and hypointense (83.3%) in the arterial phase and with a progressive enhancement pattern on dynamic contrast-enhanced images. The sensitivity of DWI for detecting IgG4-KD was significantly higher than that of T2-weighted images (100% vs. 77.4%, P = 0.034). The median number of detectable lesions was significantly greater in DWI (n = 9) than in T2-weighted images (n = 2) and dynamic contrast-enhanced images (n = 5) (P ≤ 0.008). Conclusions: The characteristic MRI findings of IgG4-KD were bilateral, multiple, renal parenchymal nodules with T2 hypointensity, diffusion restriction, and a progressive enhancement pattern. As DWI was useful in the detection of IgG4-KD, adding DWI to conventional MRI for patients suspected of having IgG4-KD may enhance the diagnosis.

  5. IgG4-related kidney disease: MRI findings with emphasis on the usefulness of diffusion-weighted imaging

    International Nuclear Information System (INIS)

    Kim, Bohyun; Kim, Jin Hee; Byun, Jae Ho; Kim, Hyoung Jung; Lee, Seung Soo; Kim, So Yeon; Lee, Moon-Gyu

    2014-01-01

    Objectives: To investigate the imaging findings of immunoglobulin G4 (IgG4)-related kidney disease (IgG4-KD) on magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI) and to evaluate the usefulness of DWI in lesion detection. Methods: This retrospective cohort study included 31 patients with IgG4-KD who underwent MRI covering both kidneys. Two radiologists reviewed in consensus the MR images to determine the distribution pattern (location, laterality, and multiplicity) and the visually assessed signal intensity (hypointense, isointense or hyperintense) of the renal lesions compared to the normal renal parenchyma on each sequence. Per-patient sensitivity for detecting IgG4-KD and the number of detectable lesions were compared in T2-weighted images, DWI, and dynamic contrast-enhanced images. Results: IgG4-KD typically manifested as bilateral (83.9%), multiple (93.5%), and renal parenchymal (87.1%) nodules appearing isointense (93.5%) on T1-weighted images, hypointense (77.4%) on T2-weighted images, hyperintense (100%) on DWI (b = 1000), and hypointense (83.3%) in the arterial phase and with a progressive enhancement pattern on dynamic contrast-enhanced images. The sensitivity of DWI for detecting IgG4-KD was significantly higher than that of T2-weighted images (100% vs. 77.4%, P = 0.034). The median number of detectable lesions was significantly greater in DWI (n = 9) than in T2-weighted images (n = 2) and dynamic contrast-enhanced images (n = 5) (P ≤ 0.008). Conclusions: The characteristic MRI findings of IgG4-KD were bilateral, multiple, renal parenchymal nodules with T2 hypointensity, diffusion restriction, and a progressive enhancement pattern. As DWI was useful in the detection of IgG4-KD, adding DWI to conventional MRI for patients suspected of having IgG4-KD may enhance the diagnosis

  6. Unusual MRI findings in grey matter heteropia

    International Nuclear Information System (INIS)

    Soto Ares, G.; Hamon-Kerautret, M.; Leclerc, X.; Pruvo, J.P.; Houlette, C.; Godefroy, O.

    1998-01-01

    We report unusual MRI patterns in patients with grey matter heterotopia. Standard T1- and T2-weighted spin-echo and inversion-recovery sequences were used in 22 patients presenting with seizures or developmental delay. The images were reviewed for signal change surrounding white matter and for atypical size, morphology or topography. We found 10 cases of subependymal heterotopias 11 of focal subcortical heterotopia and of diffuse subcortical heterotopia. On clinical or MRI grounds, 8 cases were considered unusual: 2 of the subependymal type, 2 of focal subcortical heterotopia with white matter abnormalities, 2 of focal subcortical heterotopia with no clinicoradiological correlation 1 of extensive hemispheric subcortical heterotopia and 1 of diffuse subcortical heterotopia confined to the frontal lobe. The classical classification of heterotopia enables easy radiological diagnosis even in cases with unusual patterns. In some cases, heterogeneity and high signal in surrounding white matter can be found. Cortical dysplasia is the most frequent associated malformation. (orig.)

  7. Voxel-based analysis of diffusion tensor indices in the brain in patients with Parkinson's disease

    International Nuclear Information System (INIS)

    Zhang Kaiyuan; Yu Chunshui; Zhang Yujin; Wu Xiaoli; Zhu Chaozhe; Chan Piu; Li Kuncheng

    2011-01-01

    Purpose: To investigate the abnormal diffusion in cerebral white matter and its relationship with the olfactory dysfunction in patients with Parkinson's disease (PD) through diffusion tensor imaging (DTI). Materials and methods: Diffusion tensor imaging of the cerebrum was performed in 25 patients with Parkinson's disease and 25 control subjects matched for age and sex. Differences in fractional anisotropy (FA) and mean diffusivity (MD) between these two groups were studied by voxel-based analysis of the DTI data. Correlations between diffusion indices and the olfactory function in PD patients were evaluated using the multiple regression model after controlling for the duration of the disease, Unified Parkinson's Disease Rating Sale (UPDRS), and age. Results: The damaged white and gray matter showed decreased FA or increased MD, localized bilaterally in the cerebellar and orbitofrontal cortex. In addition, in PD patients there was a positive correlation between FA values in the white matter of the left cerebellum and the thresholds of olfactory identification (TOI) and a negative correlation between MD values in the white matter of right cerebellum and the TOI. Conclusion: In patients with PD, there was disruption in the cerebellar white matter which may play an important role in the olfactory dysfunction in patients with Parkinson's disease.

  8. Diffusion-weighted magnetic resonance imaging for the initial characterization of non-fatty soft tissue tumors: correlation between T2 signal intensity and ADC values

    Energy Technology Data Exchange (ETDEWEB)

    Gondim Teixeira, Pedro Augusto [Service d' Imagerie Guilloz, CHU Nancy, Nancy (France); Universite de Lorraine, IADI, UMR S 947, Vandoeuvre-les-Nancy (France); Gay, Frederique; Blum, Alain [Service d' Imagerie Guilloz, CHU Nancy, Nancy (France); Chen, Bailiang; Felblinger, Jacques [Universite de Lorraine, IADI, UMR S 947, Vandoeuvre-les-Nancy (France); Zins, Marie [University Versailles St-Quentin, Versailles (France); Inserm, Centre for research in Epidemiology and Population Health (CESP), U1018, Villejuif (France); Sirveaux, Francois [Centre Chirurgical Emile Galle, Service de Chirurgie Traumatologique et Orthopedique, Nancy (France)

    2016-02-15

    To evaluate the performance of quantitative diffusion-weighted imaging (DWI) correlated with T2 signal in differentiating non-fatty benign from malignant tumors. A total of 76 patients with a histologically confirmed non-fatty soft tissue tumors (46 benign and 30 malignant) were prospectively included in this ethics committee approved study. All patients signed an informed consent and underwent MRI with DWI with two b values (0 and 600). ADC values from the solid components of these tumors were obtained and were correlated with the lesion's signal intensity on T2-weighted fat-saturated sequences. ADC values were obtained from adjacent normal muscle to allow calculation of tumor/muscle ADC ratios. There were 58 hyperintense and 18 iso or hypointense lesions. All hypointense lesions were benign. The mean ADC values for benign and malignant tumors were 1.47 ± 0.54 x 10{sup -3} and 1.17 ± 0.38 x 10{sup -3} mm{sup 2}/s respectively (p < 0.005). The mean ADC ratio in benign iso or hypointense tumors was significantly lower than that of hyperintense ones (0.76 ± 0.21 versus 1.58 ± 0.82 - p < 0.0001). An ADC ratio lower than 0.915 was highly specific for malignancy (96.4 %), whereas an ADC ratio higher than 1.32 was highly sensitive for benign lesions (90 %). ADC analysis can be useful in the initial characterization of T2 hyperintense non-fatty soft tissue masses, although this technique alone is not likely to change patient management. (orig.)

  9. Diffusion-weighted magnetic resonance imaging reflects activation of signal transducer and activator of transcription 3 during focal cerebral ischemia/reperfusion

    Directory of Open Access Journals (Sweden)

    Wen-juan Wu

    2017-01-01

    Full Text Available Signal transducer and activator of transcription (STAT is a unique protein family that binds to DNA, coupled with tyrosine phosphorylation signaling pathways, acting as a transcriptional regulator to mediate a variety of biological effects. Cerebral ischemia and reperfusion can activate STATs signaling pathway, but no studies have confirmed whether STAT activation can be verified by diffusion-weighted magnetic resonance imaging (DWI in rats after cerebral ischemia/reperfusion. Here, we established a rat model of focal cerebral ischemia injury using the modified Longa method. DWI revealed hyperintensity in parts of the left hemisphere before reperfusion and a low apparent diffusion coefficient. STAT3 protein expression showed no significant change after reperfusion, but phosphorylated STAT3 expression began to increase after 30 minutes of reperfusion and peaked at 24 hours. Pearson correlation analysis showed that STAT3 activation was correlated positively with the relative apparent diffusion coefficient and negatively with the DWI abnormal signal area. These results indicate that DWI is a reliable representation of the infarct area and reflects STAT phosphorylation in rat brain following focal cerebral ischemia/reperfusion.

  10. Imaging of postthalamic visual fiber tracts by anisotropic diffusion weighted MRI and diffusion tensor imaging: principles and applications

    International Nuclear Information System (INIS)

    Reinges, Marcus H.T.; Schoth, Felix; Coenen, Volker A.; Krings, Timo

    2004-01-01

    Diffusion weighted MRI offers the possibility to study the course of the cerebral white matter tracts. In the present manuscript, the basics, the technique and the limitations of diffusion tensor imaging and anisotropic diffusion weighted MRI are presented and their applications in various neurological and neurosurgical diseases are discussed with special emphasis on the visual system. A special focus is laid on the combination of fiber tract imaging, anatomical imaging and functional MRI for presurgical planning and intraoperative neuronavigation of lesions near the visual system

  11. Multilevel Deficiency of White Matter Connectivity Networks in Alzheimer’s Disease: A Diffusion MRI Study with DTI and HARDI Models

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2016-01-01

    Full Text Available Alzheimer’s disease (AD is the most common form of dementia in elderly people. It is an irreversible and progressive brain disease. In this paper, we utilized diffusion-weighted imaging (DWI to detect abnormal topological organization of white matter (WM structural networks. We compared the differences between WM connectivity characteristics at global, regional, and local levels in 26 patients with probable AD and 16 normal control (NC elderly subjects, using connectivity networks constructed with the diffusion tensor imaging (DTI model and the high angular resolution diffusion imaging (HARDI model, respectively. At the global level, we found that the WM structural networks of both AD and NC groups had a small-world topology; however, the AD group showed a significant decrease in both global and local efficiency, but an increase in clustering coefficient and the average shortest path length. We further found that the AD patients had significantly decreased nodal efficiency at the regional level, as well as weaker connections in multiple local cortical and subcortical regions, such as precuneus, temporal lobe, hippocampus, and thalamus. The HARDI model was found to be more advantageous than the DTI model, as it was more sensitive to the deficiencies in AD at all of the three levels.

  12. Interstellar matter

    International Nuclear Information System (INIS)

    Mezger, P.G.

    1978-01-01

    An overview of the formation of our galaxy is presented followed by a summary of recent work in star formation and related topics. Selected discussions are given on interstellar matter including absorption characteristics of dust, the fully ionised component of the ISM and the energy density of lyc-photons in the solar neighbourhood and the diffuse galactic IR radiation

  13. Matter reflects Antimatter

    CERN Document Server

    Bianconi, A.; Cristiano, A.; Leali, M.; Lodi Rizzini, E.; Venturelli, L.; Zurlo, N.

    2008-01-01

    It is common belief that the interaction between antimatter and ordinary solid matter is dominated by annihilation. However, non-destructive processes may play a relevant role too. One century ago E. Rutherford wrote about the "diffuse reflection" of alpha and beta particles by thin layers of different metals: "The observations ... of Geiger and Marsden on the scattering of alpha rays indicate that some of the alpha particles must suffer a deflexion of more than a right angle at a single encounter.... It will be shown that the main deductions from the theory are independent of whether the central charge is supposed to be positive or negative". Although the theory of electromagnetic scattering is in first approximation independent of the relative sign of the colliding particles, in the case where projectile antiprotons are shot against a wall of solid matter the Rutherford diffuse reflection mechanism competes with the annihilation process. So it is not obvious at all that a relevant part of an antiproton beam...

  14. Case Report: Neuro-Imaging Findings in Ataxia Telangiectasia

    Directory of Open Access Journals (Sweden)

    Farhad Mahvelati

    2004-06-01

    Full Text Available Ataxia Telangiectasia (AT is an autosomal recessive inherited disorder in which cutaneous and scleral Telangiectasia, cerebellar ataxia and immunodeficiency occur. There is a high incidence of development of malignant tumors, mainly lymphomas. Cerebellar atrophy is the most prominent abnormality and is shown better by magnetic resonance imaging (MRI than CT-Scan. Intracranial hemorrhage occurs rarely. We report a 7 years old boy who admitted for recurrent pulmonary infections. His examination showed ataxic gait with decreased deep tendon reflexes in lower extremities. He had telangiectasia in the eyes and his speech was slurred and difficult. Brain MRI showed cerebellar atrophy with diffuse hyperintensity in white matter, most prominent in occipital region, which was suggestive of leukodystrophy. This white matter change was not reported before in AT.

  15. Magnetic resonance imaging in diffuse brain injury

    International Nuclear Information System (INIS)

    Yokota, Hiroyuki; Yasuda, Kazuhiro; Mashiko, Kunihiro; Henmi, Hiroshi; Otsuka, Toshibumi; Kobayashi, Shiro; Nakazawa, Shozo

    1992-01-01

    Forty cases diagnosed as diffuse brain injury (DBI) were studied by magnetic resonance imaging (MRI) performed within 3 days after injury. These cases were divided into two groups, which were the concussion group and diffuse axonal injury (DAI) group established by Gennarelli. There were no findings on computerized tomography (CT) in the concussion group except for two cases which had a brain edema or subarachnoid hemorrhage. But on MRI, high intensity areas on T2 weighted imaging were demonstrated in the cerebral white matter in this group. Many lesions in this group were thought to be edemas of the cerebral white matter, because of the fact that on serial MRI, they were isointense. In mild types of DAI, the lesions on MRI were located only in the cerebral white matter, whereas, in the severe types of DAI, lesions were located in the basal ganglia, the corpus callosum, the dorsal part of the brain stem as well as in the cerebral white matter. As for CT findings, parenchymal lesions were not visualized especially in mild DAI. Our results suggested that the lesions in cerebral concussion were edemas in cerebral white matter. In mild DAI they were non-hemorrhagic contusion; and in severe DAI they were hemorrhagic contusions in the cerebral white matter, the basal ganglia, the corpus callosum or the dorsal part of the brain stem. (author)

  16. CT and MRI appearances of methotrexate leucoencephalopathy

    International Nuclear Information System (INIS)

    Wilks, M.J.; Tie, M.L.K.; Pozza, C.H.

    2002-01-01

    Methotrexate is a well recognised cause of diffuse symmetrical leucoencephalopathy. The widespread use of the drug in chemotherapeutic regimes necessitates awareness of this complication. A case report and a brief literature review is presented. A 20-year-old single woman presented to the Emergency Department with a 6-week history of general malaise, lower back pain and a petechial rash. From investigations including blood picture and bone marrow trephine, the diagnosis of acute lymphoblastic leukaemia (ALL) was made. Three cycles of induction chemotherapy were administered consisting of intravenous cytarabine and hydrocortisone and intrathecal methotrexate. Shortly after the third cycle of induction chemotherapy (6 weeks following diagnosis, 2 days following the last dose of intrathecal methotrexate) she presented with an acute neurological episode consisting of muteness and somnolence. Physical examination showed generalised flaccidity to all muscle groups and generalised loss of reflexes. There were no consistent cranial neuropathies and the patient was not neutropenic. Computed tomography of the brain showed extensive symmetric white matter hypodensity extending throughout the corona radiata and deep white matter tracts especially the external capsules. There was no abnormal enhancement with non-ionic contrast administration or evidence of grey matter involvement. Magnetic resonance imaging was subsequently performed, the fluid attenuated inversion recovery images (FLAIR) and T2-weighted image (T2WI) demonstrated marked white matter hyperintensity; the involvement was more extensive than demonstrated on the CT with additional involvement of the subcortical and cerebellar white matter, the basal ganglia and cortex of the mesial temporal and inferior frontal lobes. Gadolinium was not administered. A follow up study after 4 weeks of steroid and folinic acid therapy showed complete resolution of the white matter hyperintensity on the T2WI and FLAIR sequences

  17. White Matter Changes in Bipolar Disorder, Alzheimer Disease, and Mild Cognitive Impairment: New Insights from DTI

    Directory of Open Access Journals (Sweden)

    Aikaterini Xekardaki

    2011-01-01

    Full Text Available Neuropathological and neuroimaging studies have reported significant changes in white matter in psychiatric and neurodegenerative diseases. Diffusion tensor imaging (DTI, a recently developed technique, enables the detection of microstructural changes in white matter. It is a noninvasive in vivo technique that assesses water molecules' diffusion in brain tissues. The most commonly used parameters are axial and radial diffusivity reflecting diffusion along and perpendicular to the axons, as well as mean diffusivity and fractional anisotropy representing global diffusion. Although the combination of these parameters provides valuable information about the integrity of brain circuits, their physiological meaning still remains controversial. After reviewing the basic principles of DTI, we report on recent contributions that used this technique to explore subtle structural changes in white matter occurring in elderly patients with bipolar disorder and Alzheimer disease.

  18. Diffusion abnormalities of the uncinate fasciculus in Alzheimer's disease: diffusion tensor tract-specific analysis using a new method to measure the core of the tract

    International Nuclear Information System (INIS)

    Yasmin, Hasina; Nakata, Yasuhiro; Abe, Osamu; Masutani, Yoshitaka; Ohtomo, Kuni; Aoki, Shigeki; Sato, Noriko; Nemoto, Kiyotaka; Arima, Kunimasa; Furuta, Nobuo; Uno, Masatake; Hirai, Shigeo

    2008-01-01

    Our aim was to determine diffusion abnormalities in the uncinate fasciculus (UF) in Alzheimer's disease (AD) by diffusion tensor tractography (DTT) using a new method for measuring the core of the tract. We studied 19 patients with AD and 19 age-matched control subjects who underwent MRI using diffusion tensor imaging (DTI). DTT of the UF was generated. The mean diffusivity (MD) and fractional anisotropy (FA) of the core of the tract were measured after voxelized tract shape processing. Student's t-test was used to compare results between patients with AD and controls. Intraobserver correlation tests were also performed. FA was significantly lower (P 0.93 for measured FA and r > 0.92 for measured MD. Our results suggest that FA reflects progression of AD-related histopathological changes in the UF of the white matter and may represent a useful biological index in monitoring AD. Diffusion tensor tract-specific analysis with voxelized tract shape processing to measure the core of the tract may be a sensitive tool for evaluation of diffusion abnormalities of white matter tracts in AD. (orig.)

  19. Reduced artefacts and improved assessment of hyperintense brain lesions with BLADE MR imaging in patients with neurofibromatosis type 1

    Energy Technology Data Exchange (ETDEWEB)

    Kalle, Thekla von; Fabig-Moritz, Claudia; Mueller-Abt, Peter; Zieger, Michael; Winkler, Peter [Department of Paediatric Radiology, Stuttgart (Germany); Blank, Bernd [Haematology and Immunology, Department of Paediatric Oncology, Stuttgart (Germany); Wohlfarth, Katrin [Siemens Healthcare Sector, Erlangen (Germany)

    2009-11-15

    Assessment of small brain lesions in children is often compromised by pulsation, flow or movement artefacts. MRI with a rotating blade-like k-space covering (BLADE, PROPELLER) can compensate for these artefacts. We compared T2-weighted FLAIR images that were acquired with different k-space trajectories (conventional Cartesian and BLADE) to evaluate the impact of BLADE technique on the delineation of small or low-contrast brain lesions. The subject group comprised 26 children with neurofibromatosis type 1 (NF 1), who had been routinely scanned at 1.5 T for optic pathway gliomas with both techniques and who had the typical hyperintense brain lesions seen in NF 1. Four experienced radiologists retrospectively compared unlabelled 4-mm axial images with respect to the presence of artefacts, visibility of lesions, quality of contour and contrast. Both techniques were comparable in depicting hyperintense lesions as small as 2 mm independent of contrast and edge definition. Pulsation and movement artefacts were significantly less common with BLADE k-space trajectory. In 7 of 26 patients (27%), lesions and artefacts were rated as indistinguishable in conventional FLAIR, but not in BLADE FLAIR images. BLADE imaging significantly improved the depiction of lesions in T2-W FLAIR images due to artefact reduction especially in the posterior fossa. (orig.)

  20. Reduced artefacts and improved assessment of hyperintense brain lesions with BLADE MR imaging in patients with neurofibromatosis type 1

    International Nuclear Information System (INIS)

    Kalle, Thekla von; Fabig-Moritz, Claudia; Mueller-Abt, Peter; Zieger, Michael; Winkler, Peter; Blank, Bernd; Wohlfarth, Katrin

    2009-01-01

    Assessment of small brain lesions in children is often compromised by pulsation, flow or movement artefacts. MRI with a rotating blade-like k-space covering (BLADE, PROPELLER) can compensate for these artefacts. We compared T2-weighted FLAIR images that were acquired with different k-space trajectories (conventional Cartesian and BLADE) to evaluate the impact of BLADE technique on the delineation of small or low-contrast brain lesions. The subject group comprised 26 children with neurofibromatosis type 1 (NF 1), who had been routinely scanned at 1.5 T for optic pathway gliomas with both techniques and who had the typical hyperintense brain lesions seen in NF 1. Four experienced radiologists retrospectively compared unlabelled 4-mm axial images with respect to the presence of artefacts, visibility of lesions, quality of contour and contrast. Both techniques were comparable in depicting hyperintense lesions as small as 2 mm independent of contrast and edge definition. Pulsation and movement artefacts were significantly less common with BLADE k-space trajectory. In 7 of 26 patients (27%), lesions and artefacts were rated as indistinguishable in conventional FLAIR, but not in BLADE FLAIR images. BLADE imaging significantly improved the depiction of lesions in T2-W FLAIR images due to artefact reduction especially in the posterior fossa. (orig.)

  1. Blood Pressure Control in Aging Predicts Cerebral Atrophy Related to Small-Vessel White Matter Lesions

    Directory of Open Access Journals (Sweden)

    Kyle C. Kern

    2017-05-01

    Full Text Available Cerebral small-vessel damage manifests as white matter hyperintensities and cerebral atrophy on brain MRI and is associated with aging, cognitive decline and dementia. We sought to examine the interrelationship of these imaging biomarkers and the influence of hypertension in older individuals. We used a multivariate spatial covariance neuroimaging technique to localize the effects of white matter lesion load on regional gray matter volume and assessed the role of blood pressure control, age and education on this relationship. Using a case-control design matching for age, gender, and educational attainment we selected 64 participants with normal blood pressure, controlled hypertension or uncontrolled hypertension from the Northern Manhattan Study cohort. We applied gray matter voxel-based morphometry with the scaled subprofile model to (1 identify regional covariance patterns of gray matter volume differences associated with white matter lesion load, (2 compare this relationship across blood pressure groups, and (3 relate it to cognitive performance. In this group of participants aged 60–86 years, we identified a pattern of reduced gray matter volume associated with white matter lesion load in bilateral temporal-parietal regions with relative preservation of volume in the basal forebrain, thalami and cingulate cortex. This pattern was expressed most in the uncontrolled hypertension group and least in the normotensives, but was also more evident in older and more educated individuals. Expression of this pattern was associated with worse performance in executive function and memory. In summary, white matter lesions from small-vessel disease are associated with a regional pattern of gray matter atrophy that is mitigated by blood pressure control, exacerbated by aging, and associated with cognitive performance.

  2. D-BRAIN : Anatomically accurate simulated diffusion MRI brain data

    NARCIS (Netherlands)

    Perrone, Daniele; Jeurissen, Ben; Aelterman, Jan; Roine, Timo; Sijbers, Jan; Pizurica, Aleksandra; Leemans, Alexander; Philips, Wilfried

    2016-01-01

    Diffusion Weighted (DW) MRI allows for the non-invasive study of water diffusion inside living tissues. As such, it is useful for the investigation of human brain white matter (WM) connectivity in vivo through fiber tractography (FT) algorithms. Many DW-MRI tailored restoration techniques and FT

  3. Multienergy anomalous diffuse scattering

    Czech Academy of Sciences Publication Activity Database

    Kopecký, Miloš; Fábry, Jan; Kub, Jiří; Lausi, A.; Busetto, E.

    2008-01-01

    Roč. 100, č. 19 (2008), 195504/1-195504/4 ISSN 0031-9007 R&D Projects: GA AV ČR IAA100100529 Institutional research plan: CEZ:AV0Z10100523 Keywords : diffuse scattering * x-rays * structure determination Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.180, year: 2008

  4. Diffusion tensor imaging with direct cytopathological validation: characterisation of decorin treatment in experimental juvenile communicating hydrocephalus.

    Science.gov (United States)

    Aojula, Anuriti; Botfield, Hannah; McAllister, James Patterson; Gonzalez, Ana Maria; Abdullah, Osama; Logan, Ann; Sinclair, Alexandra

    2016-05-31

    In an effort to develop novel treatments for communicating hydrocephalus, we have shown previously that the transforming growth factor-β antagonist, decorin, inhibits subarachnoid fibrosis mediated ventriculomegaly; however decorin's ability to prevent cerebral cytopathology in communicating hydrocephalus has not been fully examined. Furthermore, the capacity for diffusion tensor imaging to act as a proxy measure of cerebral pathology in multiple sclerosis and spinal cord injury has recently been demonstrated. However, the use of diffusion tensor imaging to investigate cytopathological changes in communicating hydrocephalus is yet to occur. Hence, this study aimed to determine whether decorin treatment influences alterations in diffusion tensor imaging parameters and cytopathology in experimental communicating hydrocephalus. Moreover, the study also explored whether diffusion tensor imaging parameters correlate with cellular pathology in communicating hydrocephalus. Accordingly, communicating hydrocephalus was induced by injecting kaolin into the basal cisterns in 3-week old rats followed immediately by 14 days of continuous intraventricular delivery of either human recombinant decorin (n = 5) or vehicle (n = 6). Four rats remained as intact controls and a further four rats served as kaolin only controls. At 14-days post-kaolin, just prior to sacrifice, routine magnetic resonance imaging and magnetic resonance diffusion tensor imaging was conducted and the mean diffusivity, fractional anisotropy, radial and axial diffusivity of seven cerebral regions were assessed by voxel-based analysis in the corpus callosum, periventricular white matter, caudal internal capsule, CA1 hippocampus, and outer and inner parietal cortex. Myelin integrity, gliosis and aquaporin-4 levels were evaluated by post-mortem immunohistochemistry in the CA3 hippocampus and in the caudal brain of the same cerebral structures analysed by diffusion tensor imaging. Decorin significantly

  5. Focal Pancreatitis Mimicking Pancreatic Mass: Magnetic Resonance Imaging (MRI)/Magnetic Resonance Cholangiopancreatography (MRCP) Findings Including Diffusion-Weighted MRI

    International Nuclear Information System (INIS)

    Momtahen, A.J.; Balci, N.C.; Alkaade, S.; Akduman, E.I.; Burton, F.R.

    2008-01-01

    Background: Focal pancreatitis (FP) is a confined inflammation that mimics a pancreatic mass. Its imaging diagnosis is important to avoid unnecessary procedures. Purpose: To describe the spectrum of magnetic resonance imaging (MRI)/magnetic resonance cholangiopancreatography (MRCP) and diffusion-weighted MRI (DWI) findings of focal pancreatitis mimicking pancreatic masses. Material and Methods: Findings of MRI/MRCP including DWI with a b value of 0 and 600 s/mm2 in 14 patients with pancreatic masses on MRI were retrospectively reviewed and compared to normal pancreas in 14 patients as a control group. Results: FP revealed hypointense signal intensity (SI) (3/14), hypo- to isointense SI (7/14), or isointense SI (4/14) on T1-weighted images, and hypointense SI (1/14), isointense SI (5/14), iso- to hyperintense SI (7/14), or hyperintense SI (1/14) on T2-weighted images compared to remaining pancreas (RP). MRCP images revealed dilatation of the common bile duct (CBD) and main pancreatic duct (MPD) (5/14), dilatation of the MPD only (3/14), dilatation of the CBD only (3/14), and normal MPD and CBD (3/14). Both FP and RP revealed three types of time-signal intensity curves: 1) rapid rise to a peak, with a rapid decline (FP=2, RP=4), 2) slow rise to a peak, followed by a slow decline (FP=5, RP=4), and 3) slower rise to a peak, with a slow decline or plateau (FP=7, RP=6). Mean apparent diffusion coefficient (ADC) values for FP and RP were 2.09±0.18 and 2.03±0.2x10 -3 mm 2 /s, respectively. ADC values of FP and RP revealed no significant difference. Conclusion: The spectrum of imaging findings of focal pancreatitis on MRI/MRCP including DWI was described. Findings of FP were not distinctive as compared to the remaining pancreas

  6. Differential vulnerability of gray matter and white matter to intrauterine growth restriction in preterm infants at 12 months corrected age.

    Science.gov (United States)

    Padilla, Nelly; Junqué, Carme; Figueras, Francesc; Sanz-Cortes, Magdalena; Bargalló, Núria; Arranz, Angela; Donaire, Antonio; Figueras, Josep; Gratacos, Eduard

    2014-01-30

    Intrauterine growth restriction (IUGR) is associated with a high risk of abnormal neurodevelopment. Underlying neuroanatomical substrates are partially documented. We hypothesized that at 12 months preterm infants would evidence specific white-matter microstructure alterations and gray-matter differences induced by severe IUGR. Twenty preterm infants with IUGR (26-34 weeks of gestation) were compared with 20 term-born infants and 20 appropriate for gestational age preterm infants of similar gestational age. Preterm groups showed no evidence of brain abnormalities. At 12 months, infants were scanned sleeping naturally. Gray-matter volumes were studied with voxel-based morphometry. White-matter microstructure was examined using tract-based spatial statistics. The relationship between diffusivity indices in white matter, gray matter volumes, and perinatal data was also investigated. Gray-matter decrements attributable to IUGR comprised amygdala, basal ganglia, thalamus and insula bilaterally, left occipital and parietal lobes, and right perirolandic area. Gray-matter volumes positively correlated with birth weight exclusively. Preterm infants had reduced FA in the corpus callosum, and increased FA in the anterior corona radiata. Additionally, IUGR infants had increased FA in the forceps minor, internal and external capsules, uncinate and fronto-occipital white matter tracts. Increased axial diffusivity was observed in several white matter tracts. Fractional anisotropy positively correlated with birth weight and gestational age at birth. These data suggest that IUGR differentially affects gray and white matter development preferentially affecting gray matter. At 12 months IUGR is associated with a specific set of structural gray-matter decrements. White matter follows an unusual developmental pattern, and is apparently affected by IUGR and prematurity combined. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Reversibility of hyperintense globus pallidus on T 1-weighted MRI following surgery for a portosystemic shunt in an 8-year-old girl

    International Nuclear Information System (INIS)

    Ikeda, Shinji; Sera, Yoshihisa; Yoshida, Mituhiro; Ohshiro, Hajime; Uchino, Shinichiro; Seguchi, Sasa; Endo, Fumio

    1999-01-01

    An 8-year-old Japanese girl with a portosystemic shunt had shown hyperammonaemia since she was 3 years of age. MRI of her brain showed bilateral hyperintense globus pallidus. A portosystemic shunt was evident on US and angiography. She underwent surgical banding of the shunt, after which the lesion and clinical symptoms disappeared. (orig.)

  8. Asynchrony of the early maturation of white matter bundles in healthy infants: Quantitative landmarks revealed noninvasively by diffusion tensor imaging

    International Nuclear Information System (INIS)

    Dubois, J.; Perrin, M.; Mangin, J.F.; Cointepas, Y.; Duchesnay, E.; Le Bihan, D.; Hertz-Pannier, L.; Dehaene-Lambertz, G.; Dubois, J.; Dehaene-Lambertz, G.; Perrin, M.; Mangin, J.F.; Cointepas, Y.; Duchesnay, E.; Le Bihan, D.; Hertz-Pannier, L.

    2008-01-01

    Normal cognitive development in infants follows a well-known temporal sequence, which is assumed to be correlated with the structural maturation of underlying functional networks. Postmortem studies and, more recently, structural MR imaging studies have described qualitatively the heterogeneous spatio-temporal progression of white matter myelination. However, in vivo quantification of the maturation phases of fiber bundles is still lacking. We used noninvasive diffusion tensor MR imaging and tractography in twenty-three 1-4-month-old healthy infants to quantify the early maturation of the main cerebral fascicles. A specific maturation model, based on the respective roles of different maturational processes on the diffusion phenomena, was designed to highlight asynchronous maturation across bundles by evaluating the time-course of mean diffusivity and anisotropy changes over the considered developmental period. Using an original approach, a progression of maturation in four relative stages was determined in each tract by estimating the maturation state and speed, from the diffusion indices over the infants group compared with an adults group on one hand, and in each tract compared with the average over bundles on the other hand. Results were coherent with, and extended previous findings in 8 of 11 bundles, showing the anterior limb of the internal capsule and cingulum as the most immature, followed by the optic radiations, arcuate and inferior longitudinal fascicles, then the spino-thalamic tract and fornix, and finally the cortico-spinal tract as the most mature bundle. Thus, this approach provides new quantitative landmarks for further noninvasive research on brain-behavior relationships during normal and abnormal development. (authors)

  9. Sparse and Adaptive Diffusion Dictionary (SADD) for recovering intra-voxel white matter structure.

    Science.gov (United States)

    Aranda, Ramon; Ramirez-Manzanares, Alonso; Rivera, Mariano

    2015-12-01

    On the analysis of the Diffusion-Weighted Magnetic Resonance Images, multi-compartment models overcome the limitations of the well-known Diffusion Tensor model for fitting in vivo brain axonal orientations at voxels with fiber crossings, branching, kissing or bifurcations. Some successful multi-compartment methods are based on diffusion dictionaries. The diffusion dictionary-based methods assume that the observed Magnetic Resonance signal at each voxel is a linear combination of the fixed dictionary elements (dictionary atoms). The atoms are fixed along different orientations and diffusivity profiles. In this work, we present a sparse and adaptive diffusion dictionary method based on the Diffusion Basis Functions Model to estimate in vivo brain axonal fiber populations. Our proposal overcomes the following limitations of the diffusion dictionary-based methods: the limited angular resolution and the fixed shapes for the atom set. We propose to iteratively re-estimate the orientations and the diffusivity profile of the atoms independently at each voxel by using a simplified and easier-to-solve mathematical approach. As a result, we improve the fitting of the Diffusion-Weighted Magnetic Resonance signal. The advantages with respect to the former Diffusion Basis Functions method are demonstrated on the synthetic data-set used on the 2012 HARDI Reconstruction Challenge and in vivo human data. We demonstrate that improvements obtained in the intra-voxel fiber structure estimations benefit brain research allowing to obtain better tractography estimations. Hence, these improvements result in an accurate computation of the brain connectivity patterns. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Diffusion imaging and tractography of congenital brain malformations

    International Nuclear Information System (INIS)

    Wahl, Michael; Barkovich, A.J.; Mukherjee, Pratik

    2010-01-01

    Diffusion imaging is an MRI modality that measures the microscopic molecular motion of water in order to investigate white matter microstructure. The modality has been used extensively in recent years to investigate the neuroanatomical basis of congenital brain malformations. We review the basic principles of diffusion imaging and of specific techniques, including diffusion tensor imaging (DTI) and high angular resolution diffusion imaging (HARDI). We show how DTI and HARDI, and their application to fiber tractography, has elucidated the aberrant connectivity underlying a number of congenital brain malformations. Finally, we discuss potential uses for diffusion imaging of developmental disorders in the clinical and research realms. (orig.)

  11. Temperature dependence of Self-diffusion coefficient (SDC) of liquid ...

    African Journals Online (AJOL)

    PROF HORSFALL

    2018-04-09

    Apr 9, 2018 ... inverse square relationship between the natural logarithm of self-diffusion ... using the Equilibrium Molecular Dynamics (MD) and ..... Density, and Viscosity of Liquid Aluminum and. Iron. J. Phys. Chem. Ref. Data 35 ... Atomic Diffusion in Condensed Matter. Nature. 381: 137. Einstein, A (1905). Annalen der ...

  12. Gray matter heterotopias: MR and clinical features

    International Nuclear Information System (INIS)

    Moon, Tae Myung; Yoon, Jeong Hee; Chung, Chun Phil

    1995-01-01

    To evaluate types of gray matter heterotopias, associated brain anomalies, and its correlation with the patterns of seizure. We evaluated retrospectively 19 patients (male:female=10:9, mean age 21 years) with gray matter heterotopias on brain MRI. Using 1.0T superconducting MR unit, spin echo T1-, proton -density and T2-weighted images in axial, coronal and sagittal planes were obtained. Types of gray matter heterotopias were single subependymal in four patients, multiple subependymal in one, focal subcortical in eight, diffuse subcortical in two, mixed multiple subependymal and focal subcortical in four. Associated anomalies were seen in 11 patients: other neuronal migration anomalies in eight patients, corpus callosum agenesis in two, and combined holoprosencephaly and Dandy-Walker malformation in one. Fifteen patients had seizure. The patterns of seizure were not correlated with the types of heterotopias. In addition to subependymal, focal subcortical, and diffuse subcortical types, gray matter heterotopias included mixed variant of multiple subependymal and subcortical type. Schizencephaly was the most common form of accompanying anomalies, and patterns of seizure were not correlated with types of gray matter heterotopias, even though main clinical manifestation was seizure

  13. Magnetic resonance imaging of epidermoid, including diffusion weighted images and an atypical case

    International Nuclear Information System (INIS)

    Takahashi, Shoki; Higano, Shuichi; Kurihara, Noriko

    1994-01-01

    In order to study the role of magnetic resonance imaging (MRI) in diagnosing intracranial epidermoid, we evaluated the MRI findings on five cases with such tumor, all of which were surgically verified. In addition to standard spin-echo (SE) images obtained in all cases, diffusion-weighted images were acquired in two patients. In four patients, the tumor revealed to be almost isointense relative to cerebrospinal fluid (CSF) on both T 1 -and T 2 -weighted images, while it tended to show slightly hyperintense to CSF on proton-density-weighted images; thus, based on the signal intensity on standard SE images the distinction between epidermoid and arachnoid cyst may be difficult. Furthermore, the presence of the tumor which has a tendency to grow in and along the subarachnoid space causing relatively minimal mass effect may be overlooked. Diffusion-weighted images were shown to have advantages in such cases by demonstrating the tumor unequivocally as a mass of high signal, and differentiating it from arachnoid cysts. In the remaining patient, its appearance was atypical, showing bright signal on both T 1 -and T 2 -weighted images. In conclusion free of bone artifacts, multiplanar MRI with additional diffusion-weighted images provides a clear demonstration of epidermoid, and its differentiation from arachnoid cyst, thus obviating the need for CT cisternography. (author)

  14. Oxygen diffusion in soils: Understanding the factors and processes needed for modeling

    Directory of Open Access Journals (Sweden)

    José Neira

    2015-08-01

    Full Text Available Oxygen is an important element for plant growth. Reducing its concentration in the soil affects plant physiological processes such as nutrient and water uptake as well as respiration, the redox potential of soil elements and the activity of microorganisms. The main mechanism of oxygen transport in the soil is by diffusion, a dynamic process greatly influenced by soil physical properties such as texture and structure, conditioning, pore size distribution, tortuosity and connectivity. Organic matter is a modifying agent of the soil's chemical and physical properties, affecting its structure and the porous matrix, which are determinants of oxygen transport. This study reviews the theory of soil gas diffusion and the effect of soil organic matter on the soil's physical properties and transport of gases. It also reviews gas diffusion models, particularly those including the effect of soil organic matter.

  15. When mechanism matters: Bayesian forecasting using models of ecological diffusion

    Science.gov (United States)

    Hefley, Trevor J.; Hooten, Mevin B.; Russell, Robin E.; Walsh, Daniel P.; Powell, James A.

    2017-01-01

    Ecological diffusion is a theory that can be used to understand and forecast spatio-temporal processes such as dispersal, invasion, and the spread of disease. Hierarchical Bayesian modelling provides a framework to make statistical inference and probabilistic forecasts, using mechanistic ecological models. To illustrate, we show how hierarchical Bayesian models of ecological diffusion can be implemented for large data sets that are distributed densely across space and time. The hierarchical Bayesian approach is used to understand and forecast the growth and geographic spread in the prevalence of chronic wasting disease in white-tailed deer (Odocoileus virginianus). We compare statistical inference and forecasts from our hierarchical Bayesian model to phenomenological regression-based methods that are commonly used to analyse spatial occurrence data. The mechanistic statistical model based on ecological diffusion led to important ecological insights, obviated a commonly ignored type of collinearity, and was the most accurate method for forecasting.

  16. Multiple sclerosis deep grey matter: the relation between demyelination, neurodegeneration, inflammation and iron.

    Science.gov (United States)

    Haider, Lukas; Simeonidou, Constantina; Steinberger, Günther; Hametner, Simon; Grigoriadis, Nikolaos; Deretzi, Georgia; Kovacs, Gabor G; Kutzelnigg, Alexandra; Lassmann, Hans; Frischer, Josa M

    2014-12-01

    In multiple sclerosis (MS), diffuse degenerative processes in the deep grey matter have been associated with clinical disabilities. We performed a systematic study in MS deep grey matter with a focus on the incidence and topographical distribution of lesions in relation to white matter and cortex in a total sample of 75 MS autopsy patients and 12 controls. In addition, detailed analyses of inflammation, acute axonal injury, iron deposition and oxidative stress were performed. MS deep grey matter was affected by two different processes: the formation of focal demyelinating lesions and diffuse neurodegeneration. Deep grey matter demyelination was most prominent in the caudate nucleus and hypothalamus and could already be seen in early MS stages. Lesions developed on the background of inflammation. Deep grey matter inflammation was intermediate between low inflammatory cortical lesions and active white matter lesions. Demyelination and neurodegeneration were associated with oxidative injury. Iron was stored primarily within oligodendrocytes and myelin fibres and released upon demyelination. In addition to focal demyelinated plaques, the MS deep grey matter also showed diffuse and global neurodegeneration. This was reflected by a global reduction of neuronal density, the presence of acutely injured axons, and the accumulation of oxidised phospholipids and DNA in neurons, oligodendrocytes and axons. Neurodegeneration was associated with T cell infiltration, expression of inducible nitric oxide synthase in microglia and profound accumulation of iron. Thus, both focal lesions as well as diffuse neurodegeneration in the deep grey matter appeared to contribute to the neurological disabilities of MS patients. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  17. White matter differences in monozygotic twins discordant or concordant for obsessive-compulsive symptoms: a combined diffusion tensor imaging/voxel-based morphometry study.

    Science.gov (United States)

    den Braber, Anouk; van 't Ent, Dennis; Boomsma, Dorret I; Cath, Danielle C; Veltman, Dick J; Thompson, Paul M; de Geus, Eco J C

    2011-11-15

    Neuroimaging studies of obsessive-compulsive disorder (OCD) patients point to deficits in cortico-striato-thalamo-cortical circuits that might include changes in white matter. The contribution of environmental and genetic factors to the various OCD-related changes in brain structures remains to be established. White matter structures were analyzed in 140 subjects with both diffusion tensor imaging and voxel-based morphometry. We studied 20 monozygotic twin pairs discordant for obsessive-compulsive symptoms (OCS) to detect the effects of environmental risk factors for obsessive-compulsive (OC) symptomatology. Furthermore, we compared 28 monozygotic twin pairs concordant for low OCS scores with 23 twin pairs concordant for high OCS scores to detect the effects of genetic risk factors for OC symptomatology. Discordant pair analysis showed that the environmental risk was associated with an increase in dorsolateral-prefrontal white matter. Analysis of concordant pairs showed that the genetic risk was associated with a decrease in inferior frontal white matter. Various white matter tracts showed opposite effects of environmental and genetic risk factors (e.g., right medial frontal, left parietal, and right middle temporal), illustrating the need for designs that separate these classes of risk factors. Different white matter regions were affected by environmental and genetic risk factors for OC symptomatology, but both classes of risk factors might, in aggregate, create an imbalance between the indirect loop of the cortico-striato-thalamo-cortical network (to the dorsolateral-prefrontal region)-important for inhibition and switching between behaviors-and the direct loop (involving the inferior frontal region) that contributes to the initiation and continuation of behaviors. Copyright © 2011 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  18. Diffusion of condenser water discharge

    International Nuclear Information System (INIS)

    Iwakiri, Toshio

    1977-01-01

    Thermal and nuclear power stations in Japan are mostly located in coastal area, and the cooling water is discharged into sea as warm water. Recently, large interest is taken in this matter, and it is desirable to predict the diffusion of warm discharge accurately and to take effective measures for lowering the temperature. As for the methods of predicting the diffusion of warm discharge, simplified estimation, mathematical analysis and hydrographical model experiment are used corresponding to objects and conditions. As for the measures to lower temperature, the method of discharging warm water into deep sea bottom was confirmed to be very effective. In this paper, the phenomena of diffusion of warm discharge in sea, the methods of predicting the diffusion of warm discharge, and the deep sea discharge as the measure for lowering temperature are outlined. The factors concerning the diffusion of warm discharge in sea are the conditions of discharge, topography and sea state, and the diffusion is roughly divided into mixing diffusion in the vicinity of warm water outlet and eddy diffusion in distant region. It is difficult to change artificially the conditions of diffusion in distant region, and the measures of raising the rate of dilution in near region are effective, therefore the deep sea discharge is adopted. (Kako, I.)

  19. Continuous diffusion signal, EAP and ODF estimation via Compressive Sensing in diffusion MRI.

    Science.gov (United States)

    Merlet, Sylvain L; Deriche, Rachid

    2013-07-01

    In this paper, we exploit the ability of Compressed Sensing (CS) to recover the whole 3D Diffusion MRI (dMRI) signal from a limited number of samples while efficiently recovering important diffusion features such as the Ensemble Average Propagator (EAP) and the Orientation Distribution Function (ODF). Some attempts to use CS in estimating diffusion signals have been done recently. However, this was mainly an experimental insight of CS capabilities in dMRI and the CS theory has not been fully exploited. In this work, we also propose to study the impact of the sparsity, the incoherence and the RIP property on the reconstruction of diffusion signals. We show that an efficient use of the CS theory enables to drastically reduce the number of measurements commonly used in dMRI acquisitions. Only 20-30 measurements, optimally spread on several b-value shells, are shown to be necessary, which is less than previous attempts to recover the diffusion signal using CS. This opens an attractive perspective to measure the diffusion signals in white matter within a reduced acquisition time and shows that CS holds great promise and opens new and exciting perspectives in diffusion MRI (dMRI). Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Toward quantitative fast diffusion kurtosis imaging with b-values chosen in consideration of signal-to-noise ratio and model fidelity.

    Science.gov (United States)

    Kuo, Yen-Shu; Yang, Shun-Chung; Chung, Hsiao-Wen; Wu, Wen-Chau

    2018-02-01

    Diffusion kurtosis (DK) imaging is a variant of conventional diffusion magnetic resonance (MR) imaging that allows assessment of non-Gaussian diffusion. Fast DK imaging expedites the procedure by decreasing both scan time (acquiring the minimally required number of b-values) and computation time (obviating least-square curve fitting). This study aimed to investigate the applicability of fast DK imaging for both cerebral gray matter and white matter as a quantitative method. Seventeen healthy volunteers were recruited and each provided written informed consent before participation. On a 3-Tesla clinical MR system, diffusion imaging was performed with 12 b-values ranging from 0 to 4000 s/mm 2 . Diffusion encoding was along three orthogonal directions (slice selection, phase encoding, and frequency encoding) in separate series. Candidate b-values were chosen by first determining the maximum b-value (b max ) in the context of signal-to-noise ratio and then assessing the model fidelity for all b-value combinations within b max . Diffusion coefficient (D) and diffusion kurtosis coefficient (K) were derived from these candidates and assessed for their dependence on b-value combination. Our data suggested b max to be 2200 s/mm 2 as a trade-off between the percentage (~80%) of voxels statistically detectable against background and the sensitivity to non-Gaussian diffusion in both gray matter and white matter. The measurement dependence on b-value was observed predominantly in areas with a considerable amount of cerebrospinal fluid. In most gray matter and white matter, b-value combinations do not cause statistical difference in the calculated D and K. For fast DK imaging to be quantitatively applicable in both gray matter and white matter, b max should be chosen to ensure adequate signal-to-noise ratio in the majority of gray/white matter and the two nonzero b-values should be chosen in consideration of model fidelity to mitigate the dependence of derived indices on b

  1. Diffusion properties of NAA in human corpus callosum as studied with diffusion tensor spectroscopy.

    Science.gov (United States)

    Upadhyay, Jaymin; Hallock, Kevin; Erb, Kelley; Kim, Dae-Shik; Ronen, Itamar

    2007-11-01

    In diffusion tensor imaging (DTI) the anisotropic movement of water is exploited to characterize microstructure. One confounding issue of DTI is the presence of intra- and extracellular components contributing to the measured diffusivity. This causes an ambiguity in determining the underlying cause of diffusion properties, particularly the fractional anisotropy (FA). In this study an intracellular constituent, N-acetyl aspartate (NAA), was used to probe intracellular diffusion, while water molecules were used to probe the combined intra- and extracellular diffusion. NAA and water diffusion measurements were made in anterior and medial corpus callosum (CC) regions, which are referred to as R1 and R2, respectively. FA(NAA) was found to be greater than FA(Water) in both CC regions, thus indicating a higher degree of anisotropy within the intracellular space in comparison to the combined intra- and extracellular spaces. A decreasing trend in the FA of NAA and water was observed between R1 and R2, while the radial diffusivity (RD) for both molecules increased. The increase in RD(NAA) is particularly significant, thus explaining the more significant decrease in FA(NAA) between the two regions. It is suggested that diffusion tensor spectroscopy of NAA can potentially be used to further characterize microscopic anatomic organization in white matter. Copyright 2007 Wiley-Liss, Inc.

  2. Atmospheric turbulence and diffusion research

    International Nuclear Information System (INIS)

    Hosker, R.P. Jr.

    1993-01-01

    The Atmospheric Turbulence and Diffusion Division (well known in the atmospheric dispersion community as the Atmospheric Turbulence and Diffusion Laboratory, ATDL) is one of several field facilities of NOAAs Air Resources Laboratory, headquartered in Silver Spring, Maryland. The laboratory conducts research on matters of atmospheric diffusion and turbulent exchange, concerning air quality. ATDD focuses attention on the physics of the lower atmosphere, with special emphasis on the processes contributing to atmospheric transport, dispersion, deposition, and air-surface exchange, and on the development of predictive capabilities using the results of this research. Research is directed toward issues of national and global importance related to the missions of DOE, to DOE's Oak Ridge Field Office, and to NOAA. The program is divided into four major projects: plume transport and diffusion in the planetary boundary layer, complex topography, canopy micrometeorology, and air-surface exchange

  3. White matter microstructure damage in tremor-dominant Parkinson's disease patients

    International Nuclear Information System (INIS)

    Luo, ChunYan; Song, Wei; Chen, Qin; Yang, Jing; Shang, Hui-Fang; Gong, QiYong

    2017-01-01

    Resting tremor is one of the cardinal motor features of Parkinson's disease (PD). Several lines of evidence suggest resting tremor may have different underlying pathophysiological processes from those of bradykinesia and rigidity. The current study aims to identify white matter microstructural abnormalities associated with resting tremor in PD. We recruited 60 patients with PD (30 with tremor-dominant PD and 30 with nontremor-dominant PD) and 26 normal controls. All participants underwent clinical assessment and diffusion tensor MRI. We used tract-based spatial statistics to investigate white matter integrity across the entire white matter tract skeleton. Compared with both healthy controls and the nontremor-dominant PD patients, the tremor-dominant PD patients were characterized by increased mean diffusivity (MD) and axial diffusivity (AD) along multiple white matter tracts, mainly involving the cerebello-thalamo-cortical (CTC) pathway. The mean AD value in clusters with significant difference was correlated with resting tremor score in the tremor-dominant PD patients. There was no significant difference between the nontremor-dominant PD patients and controls. Our results support the notion that resting tremor in PD is a distinct condition in which significant microstructural white matter changes exist and provide evidence for the involvement of the CTC in tremor genesis of PD. (orig.)

  4. White matter pathology in ALS and lower motor neuron ALS variants: a diffusion tensor imaging study using tract-based spatial statistics.

    Science.gov (United States)

    Prudlo, Johannes; Bißbort, Charlotte; Glass, Aenne; Grossmann, Annette; Hauenstein, Karlheinz; Benecke, Reiner; Teipel, Stefan J

    2012-09-01

    The aim of this work was to investigate white-matter microstructural changes within and outside the corticospinal tract in classical amyotrophic lateral sclerosis (ALS) and in lower motor neuron (LMN) ALS variants by means of diffusion tensor imaging (DTI). We investigated 22 ALS patients and 21 age-matched controls utilizing a whole-brain approach with a 1.5-T scanner for DTI. The patient group was comprised of 15 classical ALS- and seven LMN ALS-variant patients (progressive muscular atrophy, flail arm and flail leg syndrome). Disease severity was measured by the revised version of the functional rating scale. White matter fractional anisotropy (FA) was assessed using tract-based spatial statistics (TBSS) and a region of interest (ROI) approach. We found significant FA reductions in motor and extra-motor cerebral fiber tracts in classical ALS and in the LMN ALS-variant patients compared to controls. The voxel-based TBSS results were confirmed by the ROI findings. The white matter damage correlated with the disease severity in the patient group and was found in a similar distribution, but to a lesser extent, among the LMN ALS-variant subgroup. ALS and LMN ALS variants are multisystem degenerations. DTI shows the potential to determine an earlier diagnosis, particularly in LMN ALS variants. The statistically identical findings of white matter lesions in classical ALS and LMN variants as ascertained by DTI further underline that these variants should be regarded as part of the ALS spectrum.

  5. Characterization of short white matter fiber bundles in the central area from diffusion tensor MRI

    Energy Technology Data Exchange (ETDEWEB)

    Magro, Elsa [INSERM U 1099/Universite de Rennes 1, Equipe MediCIS, Faculte de Medecine, Rennes Cedex (France); CHU Cavale Blanche, Service de Neurochirurgie, Pole Neurolocomoteur, Brest (France); Moreau, Tristan; Gibaud, Bernard [INSERM U 1099/Universite de Rennes 1, Equipe MediCIS, Faculte de Medecine, Rennes Cedex (France); Seizeur, Romuald [INSERM U 1099/Universite de Rennes 1, Equipe MediCIS, Faculte de Medecine, Rennes Cedex (France); CHU Cavale Blanche, Service de Neurochirurgie, Pole Neurolocomoteur, Brest (France); INSERM UMR 1101 LaTIM, Brest (France); Morandi, Xavier [INSERM U 1099/Universite de Rennes 1, Equipe MediCIS, Faculte de Medecine, Rennes Cedex (France); CHU Pontchaillou, Service de Neurochirurgie, Rennes (France)

    2012-11-15

    Diffusion tensor imaging and tractography allow studying white matter fiber bundles in the human brain in vivo. Electrophysiological studies and postmortem dissections permit improving our knowledge about the short association fibers connecting the pre- and postcentral gyri. The aim of this study was first to extract and analyze the features of these short fiber bundles and secondly to analyze their asymmetry according to the subjects' handedness. Ten right-handed and ten left-handed healthy subjects were included. White matter fiber bundles were extracted using a streamline tractography approach, with two seed regions of interest (ROI) taken from a parcellation of the pre- and postcentral gyri. This parcellation was achieved using T1 magnetic resonance images (MRI) and semi-automatically generated three ROIs within each gyrus. MRI tracks were reconstructed between all pairs of ROIs connecting the adjacent pre- and postcentral gyri. A quantitative analysis was performed on the number of tracks connecting each ROI pair. A statistical analysis studied the repartition of these MRI tracks in the right and left hemispheres and as a function of the subjects' handedness. The quantitative analysis showed an increased density of MRI tracks in the middle part of the central area in each hemisphere of the 20 subjects. The statistical analysis showed significantly more MRI tracks for the left hemisphere, when we consider the whole population, and this difference was presumably driven by the left-handers. These results raise questions about the functional role of these MRI tracks and their relation with laterality. (orig.)

  6. Characterization of short white matter fiber bundles in the central area from diffusion tensor MRI

    International Nuclear Information System (INIS)

    Magro, Elsa; Moreau, Tristan; Gibaud, Bernard; Seizeur, Romuald; Morandi, Xavier

    2012-01-01

    Diffusion tensor imaging and tractography allow studying white matter fiber bundles in the human brain in vivo. Electrophysiological studies and postmortem dissections permit improving our knowledge about the short association fibers connecting the pre- and postcentral gyri. The aim of this study was first to extract and analyze the features of these short fiber bundles and secondly to analyze their asymmetry according to the subjects' handedness. Ten right-handed and ten left-handed healthy subjects were included. White matter fiber bundles were extracted using a streamline tractography approach, with two seed regions of interest (ROI) taken from a parcellation of the pre- and postcentral gyri. This parcellation was achieved using T1 magnetic resonance images (MRI) and semi-automatically generated three ROIs within each gyrus. MRI tracks were reconstructed between all pairs of ROIs connecting the adjacent pre- and postcentral gyri. A quantitative analysis was performed on the number of tracks connecting each ROI pair. A statistical analysis studied the repartition of these MRI tracks in the right and left hemispheres and as a function of the subjects' handedness. The quantitative analysis showed an increased density of MRI tracks in the middle part of the central area in each hemisphere of the 20 subjects. The statistical analysis showed significantly more MRI tracks for the left hemisphere, when we consider the whole population, and this difference was presumably driven by the left-handers. These results raise questions about the functional role of these MRI tracks and their relation with laterality. (orig.)

  7. Diffusion model of solid particles in a gaseous atmosphere. Pt. 1

    International Nuclear Information System (INIS)

    Fernandez Ruiz, J.L.

    1987-01-01

    Starting from Voinov and Garipov's lagrangian statements on the problem of dynamic evolution of bubbles in liquids, this work is trying to determine some diffusion equations of solid particles in little dense matter like gases or liquids, aiming at applying it to the tracing of matter in atmospheric diffusion and the tracing of corpuscles in liquids. All the resulting equations lead to a solution given as a tensor θ ij related to the velocity states v i defined as v i = , and to the potential from which derive. One has had in mind the factor of mutual correlation between the diffusing particles. This increases the scope of application of these equations to Chemistry and to Biomedical Sciences. (author)

  8. Assessment of axonal degeneration in Alzheimer's disease with diffusion tensor MRI

    International Nuclear Information System (INIS)

    Stahl, R.; Dietrich, O.; Reiser, M.F.; Schoenberg, S.O.; Teipel, S.; Hampel, H.

    2003-01-01

    Alzheimer disease (AD) causes cortical degeneration with subsequent degenerative changes of the white matter. The aim of this study was to investigate the extent of white matter tissue damage of patients with Alzheimer's disease in comparison with healthy subjects using diffusion tensor MRI (DTI). The value of integrated parallel imaging techniques (iPAT) for reduction of image distortion was assessed. We studied 9 patients with mild AD and 10 age and gender matched healthy controls. DTI brain scans were obtained on a 1.5 tesla system (Siemens Magnetom Sonata) using parallel imaging (iPAT) and an EPI diffusion sequence with TE/TR 71 ms/6000 ms. We used an 8-element head coil and a GRAPPA reconstruction algorithm with an acceleration factor of 2. From the tensor, the mean diffusivity (D), the fractional anisotropy (FA), and the relative anisotropy (RA) of several white matter regions were determined. FA was significantly lower (p [de

  9. Automated segmentation of white matter fiber bundles using diffusion tensor imaging data and a new density based clustering algorithm.

    Science.gov (United States)

    Kamali, Tahereh; Stashuk, Daniel

    2016-10-01

    Robust and accurate segmentation of brain white matter (WM) fiber bundles assists in diagnosing and assessing progression or remission of neuropsychiatric diseases such as schizophrenia, autism and depression. Supervised segmentation methods are infeasible in most applications since generating gold standards is too costly. Hence, there is a growing interest in designing unsupervised methods. However, most conventional unsupervised methods require the number of clusters be known in advance which is not possible in most applications. The purpose of this study is to design an unsupervised segmentation algorithm for brain white matter fiber bundles which can automatically segment fiber bundles using intrinsic diffusion tensor imaging data information without considering any prior information or assumption about data distributions. Here, a new density based clustering algorithm called neighborhood distance entropy consistency (NDEC), is proposed which discovers natural clusters within data by simultaneously utilizing both local and global density information. The performance of NDEC is compared with other state of the art clustering algorithms including chameleon, spectral clustering, DBSCAN and k-means using Johns Hopkins University publicly available diffusion tensor imaging data. The performance of NDEC and other employed clustering algorithms were evaluated using dice ratio as an external evaluation criteria and density based clustering validation (DBCV) index as an internal evaluation metric. Across all employed clustering algorithms, NDEC obtained the highest average dice ratio (0.94) and DBCV value (0.71). NDEC can find clusters with arbitrary shapes and densities and consequently can be used for WM fiber bundle segmentation where there is no distinct boundary between various bundles. NDEC may also be used as an effective tool in other pattern recognition and medical diagnostic systems in which discovering natural clusters within data is a necessity. Copyright

  10. Location of lacunar infarcts correlates with cognition in a sample of non-disabled subjects with age-related white-matter changes: the LADIS study

    DEFF Research Database (Denmark)

    Benisty, S; Gouw, A A; Porcher, R

    2009-01-01

    evaluation was based on the Mini Mental Status Examination (MMSE), a modified Alzheimer Diseases Assessment Scale for global cognitive functions, and compound Z scores for memory, executive functions, speed and motor control. WMH were rated according to the Fazekas scale; the number of lacunes was assessed...... a significant negative association between the presence of lacunes in putamen/pallidum and the memory compound Z score (beta = -0.13; p = 0.038). By contrast, no significant negative association was found between cognitive parameters and the presence of lacunes in internal capsule, lobar white matter......OBJECTIVES: In cerebral small vessel disease, white-matter hyperintensities (WMH) and lacunes are both related to cognition. Still, their respective contribution in older people remains unclear. The purpose of this study is to assess the topographic distribution of lacunes and determine whether...

  11. Effects of low-level sarin and cyclosarin exposure on white matter integrity in Gulf War Veterans.

    Science.gov (United States)

    Chao, Linda L; Zhang, Yu; Buckley, Shannon

    2015-05-01

    We previously found evidence of reduced gray and white matter volume in Gulf War (GW) veterans with predicted low-level exposure to sarin (GB) and cyclosarin (GF). Because loss of white matter tissue integrity has been linked to both gray and white matter atrophy, the current study sought to test the hypothesis that GW veterans with predicted GB/GF exposure have evidence of disrupted white matter microstructural integrity. Measures of fractional anisotropy and directional (i.e., axial and radial) diffusivity were assessed from the 4T diffusion tensor images (DTI) of 59 GW veterans with predicted GB/GF exposure and 59 "matched" unexposed GW veterans (mean age: 48 ± 7 years). The DTI data were analyzed using regions of interest (ROI) analyses that accounted for age, sex, total brain gray and white matter volume, trauma exposure, posttraumatic stress disorder, current major depression, and chronic multisymptom illness status. There were no significant group differences in fractional anisotropy or radial diffusivity. However, there was increased axial diffusivity in GW veterans with predicted GB/GF exposure compared to matched, unexposed veterans throughout the brain, including the temporal stem, corona radiata, superior and inferior (hippocampal) cingulum, inferior and superior fronto-occipital fasciculus, internal and external capsule, and superficial cortical white matter blades. Post hoc analysis revealed significant correlations between higher fractional anisotropy and lower radial diffusivity with better neurobehavioral performance in unexposed GW veterans. In contrast, only increased axial diffusivity in posterior limb of the internal capsule was associated with better psychomotor function in GW veterans with predicted GB/GF exposure. The finding that increased axial diffusivity in a region of the brain that contains descending corticospinal fibers was associated with better psychomotor function and the lack of significant neurobehavioral deficits in veterans

  12. Low-grade intraventricular hemorrhage disrupts cerebellar white matter in preterm infants: evidence from diffusion tensor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Takashi; Morimoto, Masafumi; Hasegawa, Tatsuji; Morioka, Shigemi; Kidowaki, Satoshi; Moroto, Masaharu; Yamashita, Satoshi; Maeda, Hiroshi; Chiyonobu, Tomohiro; Tokuda, Sachiko; Hosoi, Hajime [Kyoto Prefectural University of Medicine, Department of Pediatrics, Graduate School of Medical Science, Kyoto (Japan); Yamada, Kei [Kyoto Prefectural University of Medicine, Department of Radiology, Graduate School of Medical Science, Kyoto (Japan)

    2015-05-01

    Recent diffusion tensor imaging (DTI) studies have demonstrated that leakage of hemosiderin into cerebrospinal fluid (CSF), which is caused by high-grade intraventricular hemorrhage (IVH), can affect cerebellar development in preterm born infants. However, a direct effect of low-grade IVH on cerebellar development is unknown. Thus, we evaluated the cerebellar and cerebral white matter (WM) of preterm infants with low-grade IVH. Using DTI tractography performed at term-equivalent age, we analyzed 42 infants who were born less than 30 weeks gestational age (GA) at birth (22 with low-grade IVH, 20 without). These infants were divided into two birth groups depending on GA, and we then compared the presence and absence of IVH which was diagnosed by cerebral ultrasound (CUS) within 10 days after birth or conventional magnetic resonance imaging (MRI) at term-equivalent age in each group. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) at the superior cerebellar peduncle (SCP), middle cerebellar peduncle (MCP), motor tract, and sensory tract were measured. In the SCP, preterm born infants with IVH had lower FA values compared with infants without IVH. In particular, younger preterm birth with IVH had lower FA values in the SCP and motor tract and higher ADC values in the MCP. Low-grade IVH impaired cerebellar and cerebral WM, especially in the SCP. Moreover, younger preterm infants exhibited greater disruptions to cerebellar WM and the motor tract than infants of older preterm birth. (orig.)

  13. Endometrial Stromal Sarcoma of the Uterus: Magnetic Resonance Imaging Findings Including Apparent Diffusion Coefficient Value and Its Correlation With Ki-67 Expression.

    Science.gov (United States)

    Li, Hai Ming; Liu, Jia; Qiang, Jin Wei; Gu, Wei Yong; Zhang, Guo Fu; Ma, Feng Hua

    2017-11-01

    This study aimed to investigate the conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) features of endometrial stromal sarcoma (ESS) including a preliminary investigation of the correlation between the apparent diffusion coefficient (ADC) value and Ki-67 expression. The clinical and MRI data of 15 patients with ESS confirmed by surgery and pathology were analyzed retrospectively. The conventional MR morphological features, signal intensity on DWI, ADC value (n = 14), and clinicopathological marker Ki-67 (n = 13) were evaluated. Of 15 patients with ESS, 13 tumors were low-grade ESS (LGESS), and the remaining 2 were high-grade ESS (HGESS); 9 tumors were located in the myometrium, 5 were located in the endometrium and/or cervical canal, and 1 was located in extrauterine. Thirteen (87%) of 15 tumors showed a homo- or heterogeneous isointensity on T1-weighted imaging and a heterogeneous hyperintensity on T2-weighted imaging. The hypointense bands were observed in 11 tumors (73%) on T2-weighted imaging. The degenerations (cystic/necrosis/hemorrhage) were observed in 7 LGESS tumors and 2 HGESS tumors. The DWI hyperintensity was observed in 13 tumors (93%) and isointensity in remaining 1. The mean ADC value of the solid components in 14 ESSs was (1.05 ± 0.20) × 10mm/s. The contrast-enhanced MRI showed an obvious enhancement in 14 tumors (93%) (heterogeneous in 7 LGESSs and 2 HGESSs; homogeneous in 5 LGESSs). The ADC value was inversely correlated with the Ki-67 expression (r = -0.613, P = 0.026). Patients with ESS showed some characteristics on conventional MRI and DWI, and there was an inverse correlation between the ADC value and Ki-67 expression.

  14. Pathways linking regional hyperintensities in the brain and slower gait.

    Science.gov (United States)

    Bolandzadeh, Niousha; Liu-Ambrose, Teresa; Aizenstein, Howard; Harris, Tamara; Launer, Lenore; Yaffe, Kristine; Kritchevsky, Stephen B; Newman, Anne; Rosano, Caterina

    2014-10-01

    Cerebral white matter hyperintensities (WMHs) are involved in the evolution of impaired mobility and executive functions. Executive functions and mobility are also associated. Thus, WMHs may impair mobility directly, by disrupting mobility-related circuits, or indirectly, by disrupting circuits responsible for executive functions. Understanding the mechanisms underlying impaired mobility in late life will increase our capacity to develop effective interventions. To identify regional WMHs most related to slower gait and to examine whether these regional WMHs directly impact mobility, or indirectly by executive functions. Cross-sectional study. Twenty-one WMH variables (i.e., total WMH volume and WMHs in 20 tracts), gait speed, global cognition (Modified Mini-Mental State Examination; 3MS), and executive functions and processing speed (Digit-Symbol Substitution Test; DSST) were assessed. An L1-L2 regularized regression (i.e., Elastic Net model) identified the WMH variables most related to slower gait. Multivariable linear regression models quantified the association between these WMH variables and gait speed. Formal tests of mediation were also conducted. Community-based sample. Two hundred fifty-three adults (mean age: 83years, 58% women, 41% black). Gait speed. In older adults with an average gait speed of 0.91m/sec, total WMH volume, WMHs located in the right anterior thalamic radiation (ATRR) and frontal corpuscallosum (CCF) were most associated with slower gait. There was a >10% slower gait for each standard deviation of WMH in CCF, ATRR or total brain (standardized beta in m/sec [p value]: -0.11 [p=0.046], -0.15 [p=0.007] and -0.14 [p=0.010], respectively). These associations were substantially and significantly attenuated after adjustment for DSST. This effect was stronger for WMH in CCF than for ATRR or total WMH (standardized beta in m/sec [p value]: -0.07 [p=0.190], -0.12 [p=0.024] and -0.10 [p=0.049], respectively). Adjustment for 3MS did not change these

  15. Voxel-based analysis of diffusion tensor indices in the brain in patients with Parkinson's disease

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Kaiyuan, E-mail: kaiyuanzhang@yahoo.cn [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Key Laboratory of Neurodegenerative Diseases, Capital Medical University, Ministry of Education (China); Yu Chunshui, E-mail: chunshuiyu826@yahoo.com.cn [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Key Laboratory of Neurodegenerative Diseases, Capital Medical University, Ministry of Education (China); Zhang Yujin, E-mail: zyjinjin@gmail.com [State Key Laboratory of Cognitive Neurosciences and Learning, Beijing Normal University, Beijing 100875 (China); Wu Xiaoli, E-mail: wendy2006315@126.com [Key Laboratory of Neurodegenerative Diseases, Capital Medical University, Ministry of Education (China) and Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Zhu Chaozhe, E-mail: czzhu@bnu.edu.cn [State Key Laboratory of Cognitive Neurosciences and Learning, Beijing Normal University, Beijing 100875 (China); Chan Piu, E-mail: pbchan@bjsap.org [Key Laboratory of Neurodegenerative Diseases, Capital Medical University, Ministry of Education (China); Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Li Kuncheng, E-mail: likuncheng1955@yahoo.com.cn [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Key Laboratory of Neurodegenerative Diseases, Capital Medical University, Ministry of Education (China)

    2011-02-15

    Purpose: To investigate the abnormal diffusion in cerebral white matter and its relationship with the olfactory dysfunction in patients with Parkinson's disease (PD) through diffusion tensor imaging (DTI). Materials and methods: Diffusion tensor imaging of the cerebrum was performed in 25 patients with Parkinson's disease and 25 control subjects matched for age and sex. Differences in fractional anisotropy (FA) and mean diffusivity (MD) between these two groups were studied by voxel-based analysis of the DTI data. Correlations between diffusion indices and the olfactory function in PD patients were evaluated using the multiple regression model after controlling for the duration of the disease, Unified Parkinson's Disease Rating Sale (UPDRS), and age. Results: The damaged white and gray matter showed decreased FA or increased MD, localized bilaterally in the cerebellar and orbitofrontal cortex. In addition, in PD patients there was a positive correlation between FA values in the white matter of the left cerebellum and the thresholds of olfactory identification (TOI) and a negative correlation between MD values in the white matter of right cerebellum and the TOI. Conclusion: In patients with PD, there was disruption in the cerebellar white matter which may play an important role in the olfactory dysfunction in patients with Parkinson's disease.

  16. Apparent diffusion coefficient measurements in progressive supranuclear palsy

    Energy Technology Data Exchange (ETDEWEB)

    Ohshita, T.; Oka, M.; Imon, Y.; Yamaguchi, S.; Mimori, Y.; Nakamura, S. [Hiroshima Univ. (Japan). School of Medicine

    2000-09-01

    We measured the apparent diffusion coefficient (ADC), using diffusion-weighted imaging (DWI) and signal intensity on T2-weighted MRI in the cerebral white matter of patients with progressive supranuclear palsy (PSP) and age-matched normal subjects. In PSP, ADC in the prefrontal and precentral white matter was significantly higher than in controls. There was no significant difference in signal intensity on T2-weighted images. The ADC did correlate with signal intensity. The distribution of the elevation of ADC may be the consequence of underlying pathological changes, such as neurofibrillary tangles or glial fibrillary tangles in the cortex. Our findings suggest that ADC measurement might be useful for demonstrating subtle neuropathological changes. (orig.)

  17. A grain-boundary diffusion model of dynamic grain growth during superplastic deformation

    International Nuclear Information System (INIS)

    Kim, Byung-Nam; Hiraga, Keijiro; Sakka, Yoshio; Ahn, Byung-Wook

    1999-01-01

    Dynamic grain growth during superplastic deformation is modelled on the basis of a grain-boundary diffusion mechanism. On the grain boundary where a static and a dynamic potential difference coexist, matter transport along the boundary is assumed to contribute to dynamic grain growth through depositing the matter on the grain surface located opposite to the direction of grain-boundary migration. The amount of the diffusive matter during deformation is calculated for an aggregate of spherical grains and is converted to the increment of mean boundary migration velocity. The obtained relationship between the strain rate and the dynamic grain growth rate is shown to be independent of deformation mechanisms, provided that the grain growth is controlled by grain-boundary diffusion. The strain dependence, strain-rate dependence and temperature dependence of grain growth predicted from this model are consistent with those observed in superplastic ZrO 2 -dispersed Al 2 O 3

  18. Diffusion in heterogeneous lattices

    Czech Academy of Sciences Publication Activity Database

    Tarasenko, Alexander; Jastrabík, Lubomír

    2010-01-01

    Roč. 256, č. 17 (2010), s. 5137-5144 ISSN 0169-4332 R&D Projects: GA AV ČR KAN301370701; GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100522 Keywords : lattice- gas systems * diffusion * Monte Carlo simulations Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.795, year: 2010

  19. Diffusion-weighted MRI of myelination in the rat brain following treatment with gonadal hormones

    International Nuclear Information System (INIS)

    Prayer, D.; Roberts, T.; Barkovich, A.J.; Prayer, L.; Kucharczyk, J.; Moseley, M.; Arieff, A.

    1997-01-01

    Previous studies have demonstrated the ability of high-resolution diffusion-weighted MRI to show maturation of white-matter structures in the developing rat brain. The purpose of this study was to investigate the influence of gonadal steroid hormones on the rate of this development. Starting from their second postnatal day, 16 rat-pups of either sex were repeatedly treated with subcutaneous implants containing 17-beta estradiol or delta-androstene 3,17 dione, respectively. Serial T1-, T2- and diffusion-weighted MRI was performed weekly for 8 weeks using a 4.7 T unit. Maturation of anterior optic pathways and hemisphere commissures was assessed. Diffusion-weighted images were processed to produce ''anisotropy index maps'', previously shown to be sensitive to white-matter maturation. Compared with untreated rat-pups, estrogen-treated animals showed accelerated, and testosterone-treated animals delayed maturation on anisotropy index maps and histological sections. In all animals, maturational changes appeared earlie on anisotropy index maps than on other MRI sequences or on myelin-sensitive stained sections. Diffusion-weighted imaging, and the construction of spatial maps sensitive to diffusion anisotropy, seem to be the most sensitive approach for the detection of maturational white-matter changes, and thus may hold potential for early diagnosis of temporary delay or permanent disturbances of white-matter development. (orig.). With 6 figs., 1 tab

  20. Diffusion-weighted MRI of myelination in the rat brain following treatment with gonadal hormones

    Energy Technology Data Exchange (ETDEWEB)

    Prayer, D. [Department of Radiology, Section of Neuroradiology, University of Vienna (Austria); Roberts, T. [Department of Radiology, Section of Neuroradiology, University of California at San Francisco (UCSF), CA (United States); Barkovich, A.J. [Department of Radiology, Section of Neuroradiology, University of California at San Francisco (UCSF), CA (United States); Prayer, L. [Department of Radiology, Section of Neuroradiology, University of Vienna (Austria); Kucharczyk, J. [Department of Radiology, Section of Neuroradiology, University of California at San Francisco (UCSF), CA (United States); Moseley, M. [Department of Radiology, Section of Neuroradiology, University of California at San Francisco (UCSF), CA (United States); Arieff, A. [Department of Medicine, Geriatrics Section, Veteran`s Affairs Medical Center and University of California at San Francisco (UCSF), CA (United States)

    1997-05-01

    Previous studies have demonstrated the ability of high-resolution diffusion-weighted MRI to show maturation of white-matter structures in the developing rat brain. The purpose of this study was to investigate the influence of gonadal steroid hormones on the rate of this development. Starting from their second postnatal day, 16 rat-pups of either sex were repeatedly treated with subcutaneous implants containing 17-beta estradiol or delta-androstene 3,17 dione, respectively. Serial T1-, T2- and diffusion-weighted MRI was performed weekly for 8 weeks using a 4.7 T unit. Maturation of anterior optic pathways and hemisphere commissures was assessed. Diffusion-weighted images were processed to produce ``anisotropy index maps``, previously shown to be sensitive to white-matter maturation. Compared with untreated rat-pups, estrogen-treated animals showed accelerated, and testosterone-treated animals delayed maturation on anisotropy index maps and histological sections. In all animals, maturational changes appeared earlie on anisotropy index maps than on other MRI sequences or on myelin-sensitive stained sections. Diffusion-weighted imaging, and the construction of spatial maps sensitive to diffusion anisotropy, seem to be the most sensitive approach for the detection of maturational white-matter changes, and thus may hold potential for early diagnosis of temporary delay or permanent disturbances of white-matter development. (orig.). With 6 figs., 1 tab.