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Sample records for conventional diffusion imaging

  1. A preliminary diffusional kurtosis imaging study of Parkinson disease: comparison with conventional diffusion tensor imaging

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    Kamagata, Koji; Kamiya, Kouhei; Suzuki, Michimasa; Hori, Masaaki; Yoshida, Mariko; Aoki, Shigeki [Juntendo University School of Medicine, Department of Radiology, Bunkyo-ku, Tokyo (Japan); Tomiyama, Hiroyuki; Hatano, Taku; Motoi, Yumiko; Hattori, Nobutaka [Juntendo University School of Medicine, Department of Neurology, Tokyo (Japan); Abe, Osamu [Nihon University School of Medicine, Department of Radiology, Tokyo (Japan); Shimoji, Keigo [National Center of Neurology and Psychiatry Hospital, Department of Radiology, Tokyo (Japan)

    2014-03-15

    Diffusional kurtosis imaging (DKI) is a more sensitive technique than conventional diffusion tensor imaging (DTI) for assessing tissue microstructure. In particular, it quantifies the microstructural integrity of white matter, even in the presence of crossing fibers. The aim of this preliminary study was to compare how DKI and DTI show white matter alterations in Parkinson disease (PD). DKI scans were obtained with a 3-T magnetic resonance imager from 12 patients with PD and 10 healthy controls matched by age and sex. Tract-based spatial statistics were used to compare the mean kurtosis (MK), mean diffusivity (MD), and fractional anisotropy (FA) maps of the PD patient group and the control group. In addition, a region-of-interest analysis was performed for the area of the posterior corona radiata and superior longitudinal fasciculus (SLF) fiber crossing. FA values in the frontal white matter were significantly lower in PD patients than in healthy controls. Reductions in MK occurred more extensively throughout the brain: in addition to frontal white matter, MK was lower in the parietal, occipital, and right temporal white matter. The MK value of the area of the posterior corona radiata and SLF fiber crossing was also lower in the PD group. DKI detects changes in the cerebral white matter of PD patients more sensitively than conventional DTI. In addition, DKI is useful for evaluating crossing fibers. By providing a sensitive index of brain pathology in PD, DKI may enable improved monitoring of disease progression. (orig.)

  2. Imaging features in conventional MRI, spectroscopy and diffusion weighted images of hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS).

    Science.gov (United States)

    Bender, Benjamin; Klose, Uwe; Lindig, Tobias; Biskup, Saskia; Nägele, Thomas; Schöls, Ludger; Karle, Kathrin N

    2014-12-01

    Hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS) is a rare autosomal dominant disease caused by mutations within the colony stimulating factor 1 receptor (CSF1R) gene. While a small number of reports on imaging findings in routine MRI exist, reported imaging findings in DWI and spectroscopy are scarce, and limited to not genetically proven case reports. We assessed MRI including DWI and MR spectroscopy in six patients with HDLS and two asymptomatic mutation carriers. A total of 13 MRIs were evaluated and a score of the white-matter lesion (WML) load was calculated. The course of MR abnormalities was followed for 6-19 months in four patients and 95 months in one carrier. MRI revealed widespread white-matter lesions of patchy or confluent pattern especially in the frontal and occipital lobe. The pyramidal tract was less affected than the surrounding tissue in all symptomatic patients on conventional T2WI. Three of four cases with DWI showed small dots of diffusion restriction within WML. Spectroscopy showed increased levels of mIns, Cho and lactate while NAA was decreased. Asymptomatic mutation carriers had, for the age of the patients, unusually pronounced unspecific WMLs. No diffusion restriction or alterations in metabolite levels could be detected in asymptomatic mutation carriers. Microbleeds were not found in any patient. Diffusion restriction seems to be a typical imaging pattern visible in patients with active disease progression in HDLS. Spectroscopic findings and the absence of microbleeds differ clearly from reported findings in CADASIL and subcortical arteriosclerotic encephalopathy. While the distribution and character of WMLs in asymptomatic cases remain unspecific they are likely to represent subclinical markers of HDLS.

  3. Evolution of unilateral perinatal arterial ischemic stroke on conventional and diffusion-weighted MR imaging

    NARCIS (Netherlands)

    J. Dudink (Jeroen); E. Mercuri; L. Al-Nakib; P. Govaert (Paul); S.J. Counsell (Serena); M.A. Rutherford; F.M. Cowan

    2009-01-01

    textabstractBACKGROUND AND PURPOSE: Knowledge of the sequence of signal-intensity (SI) changes on conventional and diffusion-weighted MR imaging (DWI) following perinatal arterial ischemic stroke (PAIS) is limited, adding to the difficulty in timing the onset of PAIS. We hypothesized that SI changes

  4. Diagnostic performance of conventional diffusion weighted imaging and diffusion tensor imaging for the liver fibrosis and inflammation

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    Tosun, Mesude, E-mail: mesude.tosun@kocaeli.edu.tr [Department of Radiology, School of Medicine, University of Kocaeli (Turkey); Inan, Nagihan, E-mail: inannagihan@ekolay.net [Department of Radiology, School of Medicine, University of Kocaeli (Turkey); Sarisoy, Hasan Tahsin, E-mail: htssarisoy@yahoo.com [Department of Radiology, School of Medicine, University of Kocaeli (Turkey); Akansel, Gur, E-mail: gakansel@gmail.com [Department of Radiology, School of Medicine, University of Kocaeli (Turkey); Gumustas, Sevtap, E-mail: svtgumustas@hotmail.com [Department of Radiology, School of Medicine, University of Kocaeli (Turkey); Gürbüz, Yeşim, E-mail: yesimgurbuz2002@yahoo.com [Department of Pathology, School of Medicine, University of Kocaeli (Turkey); Demirci, Ali, E-mail: alidemirci@kocaeli.edu.tr [Department of Radiology, School of Medicine, University of Kocaeli (Turkey)

    2013-02-15

    Objective: To evaluate the diagnostic accuracy of liver apparent diffusion coefficient (ADC) measured with conventional diffusion-weighted imaging (CDI) and diffusion tensor imaging (DTI) for the diagnosis of liver fibrosis and inflammation. Materials and methods: Thirty-seven patients with histologic diagnosis of chronic viral hepatitis and 34 healthy volunteers were included in this prospective study. All patients and healthy volunteers were examined by 3 T MRI. CDI and DTI were performed using a breath-hold single-shot echo-planar spin echo sequence with b factors of 0 and 1000 s/mm{sup 2}. ADCs were obtained with CDI and DTI. Histopathologically, fibrosis of the liver parenchyma was classified with the use of a 5-point scale (0–4) and inflammation was classified with use of a 4-point scale (0–3) in accordance with the METAVIR score. Quantitatively, signal intensity and the ADCs of the liver parenchyma were compared between patients stratified by fibrosis stage and inflammation grade. Results: With a b factor of 1000 s/mm{sup 2}, the signal intensity of the cirrhotic livers was significantly higher than those of the normal volunteers. In addition, ADCs reconstructed from CDI and DTI of the patients were significantly lower than those of the normal volunteers. Liver ADC values inversely correlated with fibrosis and inflammation but there was only statistically significant for inflammatory grading. CDI performed better than DTI for the diagnosis of fibrosis and inflammation. Conclusion: ADC values measured with CDI and DTI may help in the detection of liver fibrosis. They may also give contributory to the inflammatory grading, particularly in distinguishing high from low grade.

  5. NI-82DIFFUSION AND CONVENTIONAL MR IMAGING GENOMIC BIOMARKER SIGNATURE FOR EGFR MUTATION IDENTIFICATION IN GLIOBLASTOMA

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    Wassal, Eslam; Zinn, Pascal; Colen, Rivka

    2014-01-01

    PURPOSE: To create a diffusion and conventional MR imaging biomarker signature in order to identify those Glioblastoma (GBM) patients with EGFR mutation status. EGFR is the cell-surface receptor for members of the epidermal growth factor family(EGF-family)of extracellular protein ligands,a subfamily of receptor tyrosine kinases. EGFR gene expression is present in 40% of GBM patients.Identification of EGFR as an oncogene has led to the development of anticancer therapeutics directed against EGFR.Thus,a non-invasive imaging surrogate that predicts EGFR mutation status will help stratify patients into therapy and clinical trials. MATERIALS AND METHODS: We identified 80 treatment-naïve patients from TCGA who had both gene and microRNA expression profiles including the EGFR mutation status and pretreatment MRI from The Cancer Imaging Archive (TCIA). Qualitative VASARI imaging features for these 80 patients were assessed by 3 independent neuroradiologists and consensus was reached. Quantitative volumetric analysis was done in the 3D Slicer software 3.6 using segmentation module.Fluid Attenuated Inversion Recovery (FLAIR)was used for segmentation of the edema and post-contrast T1 weighted imaging(T1W1)for segmentation of enhancement and necrosis.Diffusion was analyzed in Olea Sphere 2.3 and Conventional FLAIR/post- contrast T1WI was registered to DWI/ADC maps. ADC, FLAIR, T1 Gadolinium enhancement values were measured using the ROI based method, in the perilesional edema/non-enhancing tumor and the enhancing tumor zones, dividing the perilesional edema/non-enhancing tumor into 3 zones each of 1 cm width, 3 ROI measurements were taken from each zone. Each quantitative feature was correlated to EGFR mutation status to create the imaging biomarker signature predictive of EGFR mutation status. Survival analysis was done in all cases. RESULTS: A diffusion and conventional MR imaging biomarker signature was created that predicted EGFR mutation status. CONCLUSIONS: EGFR

  6. Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

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    Fonte, Mariana Vieira de Melo da; Otaduy, Maria Concepcion Garcia; Lucato, Leandro Tavares; Reed, Umbertina Conti; Leite, Claudia da Costa [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Inst. de Radiologia]. E-mail: mvmfonte@uol.com.br; Costa, Maria Olivia Rodrigues; Amaral, Raquel Portugal Guimaraes [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Radiologia; Reed, Umbertina Conti [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Neurologia; Rosemberg, Sergio [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Dept. de Patologia

    2008-11-15

    To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumors characteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, and diffusion-weighted imaging and spectroscopy findings. In most of cases the tumors were centered in the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T 1-weighted images and intermediate/hyperintense on T 2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquired with STEAM technique (n = 6) demonstrated decreased Na a / Cr ratio (83.3%) and increased Co/Cr (100%) and ml/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors. (author)

  7. Transient Splenial Lesion of Corpus Callosum Associated with Antiepileptic Drug: Conventional and Diffusion-weighted Magnetic Resonance Images

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    Hakyemez, B.; Erdogan, C.; Yildirim, N.; Gokalp, G.; Parlak, M. [Uludag Univ. Medical School, Bursa (Turkey). Dept. of Radiology

    2005-11-01

    Transient focal lesions of splenium of corpus callosum can be seen as a component of many central nervous system diseases, including antiepileptic drug toxicity. The conventional magnetic resonance (MR) findings of the disease are characteristic and include ovoid lesions with high signal intensity at T2-weighted MRI. Limited information exists about the diffusion-weighted MRI characteristics of these lesions vanishing completely after a period of time. We examined the conventional, FLAIR, and diffusion-weighted MR images of a patient complaining of depressive mood and anxiety disorder after 1 year receiving antiepileptic medication.

  8. Imaging abnormalities in sporadic hemiplegic migraine on conventional MRI, diffusion and perfusion MRI and MRS.

    Science.gov (United States)

    Jacob, A; Mahavish, K; Bowden, A; Smith, E T S; Enevoldson, P; White, R P

    2006-08-01

    Prolonged hemiparetic migraine aura can cause diagnostic confusion and be mistaken for ischaemic stroke occurring during the course of a migraine--'migrainous infarction'. We report a case of prolonged hemiparesis occurring during the course of a migraine attack. Though initially confused with migrainous infarction, we suggest with sequential magnetic resonance imaging, magnetic resonance angiography, diffusion, perfusion images and magnetic resonance spectroscopy that the hemiplegia was not of vascular origin and that the patient had sporadic hemiplegic migraine. We hypothesize that the mechanisms of sporadic hemiplegic migraine probably lie at a cellular level, similiar to familial hemiplegic migraine.

  9. Atypical idiopathic inflammatory demyelinating lesions (IIDL): Conventional and diffusion-weighted MR imaging (DWI) findings in 42 cases

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    Koelblinger, Claus; Fruehwald-Pallamar, Julia [Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna (Austria); Kubin, Klaus [CT/MRI Institut Dr. Klaus Kubin, Salzburg (Austria); Wallner-Blazek, Mirja [Department of Neurology, Medical University Graz, Graz (Austria); Hauwe, Luc van den [Department of Radiology, Medical University of Antwerp, Antwerp (Belgium); Macedo, Leonardo [Department of Radiology, CEDIMAGEM, Centro - Juiz de Fora (Brazil); Puchner, Stefan B. [Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna (Austria); Thurnher, Majda M., E-mail: majda.thurnher@meduniwien.ac.at [Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna (Austria)

    2013-11-01

    Introduction: The purpose of this study was to evaluate MR imaging characteristics with conventional and advanced MR imaging techniques in patients with IIDL. Methods: MR images of the brain in 42 patients (20 male, 22 female) with suspected or known multiple sclerosis (MS) from four institutions were retrospectively analyzed. Lesions were classified into five different subtypes: (1) ring-like lesions; (2) Balo-like lesions; (3) diffuse infiltrating lesions; (4) megacystic lesions; and (5) unclassified lesions. The location, size, margins, and signal intensities on T1WI, T2WI, and diffusion-weighted images (DWI), and the ADC values/ratios for all lesions, as well as the contrast enhancement pattern, and the presence of edema, were recorded. Results: There were 30 ring-like, 10 Balo-like, 3 megacystic-like and 16 diffuse infiltrating-like lesions were detected. Three lesions were categorized as unclassified lesions. Of the 30 ring-like lesions, 23 were hypointense centrally with a hyperintense rim. The mean ADC, measured centrally, was 1.50 ± 0.41 × 10{sup −3} mm{sup 2}/s. The mean ADC in the non-enhancing layers of the Balo-like lesions was 2.29 ± 0.17 × 10{sup −3} mm{sup 2}/s, and the mean ADC in enhancing layers was 1.03 ± 0.30 × 10{sup −3} mm{sup 2}/s. Megacystic lesions had a mean ADC of 2.14 ± 0.26 × 10{sup −3} mm{sup 2}/s. Peripheral strong enhancement with high signal on DWI was present in all diffuse infiltrating lesions. Unclassified lesions showed a mean ADC of 1.43 ± 0.13 mm{sup 2}/s. Conclusion: Restriction of diffusion will be seen in the outer layers of active inflammation/demyelination in Balo-like lesions, in the enhancing part of ring-like lesions, and at the periphery of infiltrative-type lesions.

  10. q-space and conventional diffusion imaging of axon and myelin damage in the rat spinal cord after axotomy.

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    Farrell, Jonathan A D; Zhang, Jiangyang; Jones, Melina V; Deboy, Cynthia A; Hoffman, Paul N; Landman, Bennett A; Smith, Seth A; Reich, Daniel S; Calabresi, Peter A; van Zijl, Peter C M

    2010-05-01

    Parallel and perpendicular diffusion properties of water in the rat spinal cord were investigated 3 and 30 days after dorsal root axotomy, a specific insult resulting in early axonal degeneration followed by later myelin damage in the dorsal column white matter. Results from q-space analysis (i.e., the diffusion probability density function) obtained with strong diffusion weighting were compared to conventional anisotropy and diffusivity measurements at low b-values, as well as to histology for axon and myelin damage. q-Space contrasts included the height (return to zero displacement probability), full width at half maximum, root mean square displacement, and kurtosis excess of the probability density function, which quantifies the deviation from gaussian diffusion. Following axotomy, a significant increase in perpendicular diffusion (with decreased kurtosis excess) and decrease in parallel diffusion (with increased kurtosis excess) were found in lesions relative to uninjured white matter. Notably, a significant change in abnormal parallel diffusion was detected from 3 to 30 days with full width at half maximum, but not with conventional diffusivity. Also, directional full width at half maximum and root mean square displacement measurements exhibited different sensitivities to white matter damage. When compared to histology, the increase in perpendicular diffusion was not specific to demyelination, whereas combined reduced parallel diffusion and increased perpendicular diffusion was associated with axon damage. (c) 2010 Wiley-Liss, Inc.

  11. Conventional 3T brain MRI and diffusion tensor imaging in the diagnostic workup of early stage parkinsonism

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    Meijer, Frederick J.A. [Radboud University Nijmegen Medical Center, Department of Radiology and Nuclear Medicine, Nijmegen (Netherlands); Rumund, Anouke van; Tuladhar, Anil M.; Aerts, Marjolein B.; Titulaer, Imke; Esselink, Rianne A.J.; Bloem, Bastiaan R. [Radboud University Nijmegen Medical Center, Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen (Netherlands); Verbeek, Marcel M. [Radboud University Nijmegen Medical Center, Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen (Netherlands); Radboud University Nijmegen Medical Center, Department of Laboratory Medicine, Nijmegen (Netherlands); Goraj, Bozena [Radboud University Nijmegen Medical Center, Department of Radiology and Nuclear Medicine, Nijmegen (Netherlands); Medical Center of Postgraduate Education, Department of Diagnostic Imaging, Warsaw (Poland)

    2015-07-15

    The aim of this study is to evaluate whether the diagnostic accuracy of 3 T brain MRI is improved by region of interest (ROI) measures of diffusion tensor imaging (DTI), to differentiate between neurodegenerative atypical parkinsonism (AP) and Parkinson's disease (PD) in early stage parkinsonism. We performed a prospective observational cohort study of 60 patients presenting with early stage parkinsonism and initial uncertain diagnosis. At baseline, patients underwent a 3 T brain MRI including DTI. After clinical follow-up (mean 28.3 months), diagnoses could be made in 49 patients (30 PD and 19 AP). Conventional brain MRI was evaluated for regions of atrophy and signal intensity changes. Tract-based spatial statistics and ROI analyses of DTI were performed to analyze group differences in mean diffusivity (MD) and fractional anisotropy (FA), and diagnostic thresholds were determined. Diagnostic accuracy of conventional brain MRI and DTI was assessed with the receiver operating characteristic (ROC). Significantly higher MD of the centrum semiovale, body corpus callosum, putamen, external capsule, midbrain, superior cerebellum, and superior cerebellar peduncles was found in AP. Significantly increased MD of the putamen was found in multiple system atrophy-parkinsonian form (MSA-P) and increased MD in the midbrain and superior cerebellar peduncles in progressive supranuclear palsy (PSP). The diagnostic accuracy of brain MRI to identify AP as a group was not improved by ROI measures of MD, though the diagnostic accuracy to identify MSA-P was slightly increased (AUC 0.82 to 0.85). The diagnostic accuracy of brain MRI to identify AP as a group was not improved by the current analysis approach to DTI, though DTI measures could be of added value to identify AP subgroups. (orig.)

  12. EXPERIMENTAL STUDY OF INFLAMMATORY AND METASTATIC LYMPH NODES WITH DIFFUSION WEIGHTED IMAGING ON ANIMAL MODEL: COMPARISON WITH CONVENTIONAL METHODS

    Institute of Scientific and Technical Information of China (English)

    Hua-dan Xue; Shuo Li; Hong-yi Sun; Zheng-yu Jin; Fei Sun

    2008-01-01

    Objective To investigate the feasibility of magnetic resonance (MR) diffusion weighted imaging (DWI) in discriminating inflammatory from VX2 carcinoma metastatic lymph nodes in rabbit model. Methods Twenty New Zealand white rabbits were randomly divided into 2 groups. Complete Freund's adjuvant was injected into the bilateral dorsal footpads to set up ipsilateral lymphadenitis model (n = 10), and the other 10 rabbits received a subcutaneous implantation of VX2 tumor cell suspension (1.5×107 cells/mL) in both thighs to set up metastatic lymph node model. MR imaging scan covering the popliteal fossa and iliac fossa including short time inversion recovery echo-planar imaging DWI (STIR-EPI-DWI), T1-weighted imaging (T1WI) and T2-weighted imaging (T2WI) was performed 2 weeks after injection. T2WI signal intensity (SI), DWI SI, long/short axial ratio (LSR) and apparent diffusion coefficient (ADC) values of the lymph nodes were evaluated in all cases. Right after MR imaging scan, popliteal and iliac fossa lymph nodes were collected for hematoxylin-eosin staining. Results Totally 33 lymph nodes larger than 5 mm, including 22 inflammatory and 11 metastatic ones, were successfully isolated and taken into pathological analysis. LSR showed no significant difference between the inflammatory and malignant lymph nodes (P > 0.05). Both benign and malignant lymph nodes appeared iso-intense on TIWI and hyperintense on both T2WI and DWI images with an even lower TIWI and higher T2WI SI core at the hilum. Both T2WI and DWI SI showed no significant difference between two pathological groups (P > 0.01) in popli-teal fossa. The mean ADC value of inflammatory nodes [(1.199 ± 0.281)×10-3 mm2/s] was significantly higher than that of metastatic nodes [(0.858 ± 0.090)×10-3 mm2/s, p < 0.01]. On ADC map, a high ADC value central area could be seen in most of the lymph nodes no matter benign or malignant. ADC value gave out the largest area under curve (AUCADC = 0.955) compared with other

  13. Readout-segmented echo-planar diffusion-weighted imaging in the assessment of orbital tumors: comparison with conventional single-shot echo-planar imaging in image quality and diagnostic performance.

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    Xu, Xiaoquan; Wang, Yanjun; Hu, Hao; Su, Guoyi; Liu, Hu; Shi, Haibin; Wu, Feiyun

    2017-01-01

    Background Readout-segmented echo-planar imaging (RS-EPI) could improve the imaging quality of diffusion-weighted imaging (DWI) in various organs. However, whether it could improve the imaging quality and diagnostic performance for the patients with orbital tumors is still unknown. Purpose To compare the image quality and diagnostic performance of RS-EPI DWI with that of conventional single-shot EPI (SS-EPI) DWI in patients with orbital tumors. Material and Methods SS-EPI and RS-EPI DW images of 32 patients with pathologically diagnosed orbital tumors were retrospectively analyzed. Qualitative imaging parameters (imaging sharpness, geometric distortion, ghosting artifacts, and overall imaging quality) and quantitative imaging parameters (apparent diffusion coefficient [ADC], signal-to-noise ratio [SNR], contrast, and contrast-to-noise ratio [CNR]) were assessed by two independent radiologists, and compared between SS-EPI and RS-EPI DWI. Receiver operating characteristic curves were used to determine the diagnostic value of ADC in differentiating malignant from benign orbital tumors. Results RS-EPI DW imaging produced less geometric distortion and ghosting artifacts, and better imaging sharpness and overall imaging quality than SS-EPI DWI (for all, P P P P P = 0.137). There was no significant difference on the diagnostic performance between SS-EPI and RS-EPI DWI, when using ADC as the differentiating index ( P = 0.529). Conclusion Compared with SS-EPI, RS-EPI DWI provided significantly better imaging quality and comparable diagnostic performance in differentiating malignant from benign orbital tumors.

  14. Reduced field-of -view diffusion-weighted magnetic resonance imaging of the pancreas: Comparison with conventional single-shot echo-planar imaging

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    Kim, Hyung Jin; Lee, Jeong Min; Yoon, Jeong Hee; Jang, Jin Young; Kim, Sun Whe; Ryu, Ji Kon; Han, Joon Koo; Choi, Byung Ihn [Seoul National University Hospital, Seoul (Korea, Republic of); Kannengiesser, Stephan [Siemens Healthcare, Erlangen (Germany)

    2015-12-15

    To investigate the image quality (IQ) and apparent diffusion coefficient (ADC) of reduced field-of-view (FOV) diffusion-weighted imaging (DWI) of pancreas in comparison with full FOV DWI. In this retrospective study, 2 readers independently performed qualitative analysis of full FOV DWI (FOV, 38 × 38 cm; b-value, 0 and 500 s/mm{sup 2}) and reduced FOV DWI (FOV, 28 × 8.5 cm; b-value, 0 and 400 s/mm{sup 2}). Both procedures were conducted with a two-dimensional spatially selective radiofrequency excitation pulse, in 102 patients with benign or malignant pancreatic diseases (mean size, 27.5 ± 14.4 mm). The study parameters included 1) anatomic structure visualization, 2) lesion conspicuity, 3) artifacts, 4) IQ score, and 5) subjective clinical utility for confirming or excluding initially considered differential diagnosis on conventional imaging. Another reader performed quantitative ADC measurements of focal pancreatic lesions and parenchyma. Wilcoxon signed-rank test was used to compare qualitative scores and ADCs between DWI sequences. Mann Whitney U-test was used to compare ADCs between the lesions and parenchyma. On qualitative analysis, reduced FOV DWI showed better anatomic structure visualization (2.76 ± 0.79 at b = 0 s/mm{sup 2} and 2.81 ± 0.64 at b = 400 s/mm{sup 2}), lesion conspicuity (3.11 ± 0.99 at b = 0 s/mm{sup 2} and 3.15 ± 0.79 at b = 400 s/mm{sup 2}), IQ score (8.51 ± 2.05 at b = 0 s/mm{sup 2} and 8.79 ± 1.60 at b = 400 s/mm{sup 2}), and higher clinical utility (3.41 ± 0.64), as compared to full FOV DWI (anatomic structure, 2.18 ± 0.59 at b = 0 s/mm{sup 2} and 2.56 ± 0.47 at b = 500 s/mm{sup 2}; lesion conspicuity, 2.55 ± 1.07 at b = 0 s/mm{sup 2} and 2.89 ± 0.86 at b = 500 s/mm{sup 2}; IQ score, 7.13 ± 1.83 at b = 0 s/mm{sup 2} and 8.17 ± 1.31 at b = 500 s/mm{sup 2}; clinical utility, 3.14 ± 0.70) (p < 0.05). Artifacts were significantly improved on reduced FOV DWI (2.65 ± 0.68) at b = 0 s/mm{sup 2} (full FOV DWI, 2.41 ± 0.63) (p

  15. Diffusion weighted imaging in the liver

    Institute of Scientific and Technical Information of China (English)

    Petra; G; Kele; Eric; J; van; der; Jagt

    2010-01-01

    Diffusion weighted magnetic resonance imaging (DWI) is an imaging technique which provides tissue contrast by the measurement of diffusion properties of water molecules within tissues. Diffusion is expressed in an apparent diffusion coefficient (ADC), which reflects the diffusion properties unique to each type of tissue. DWI has been originally used in neuroradiology. More recently, DWI has increasingly been used in addition to conventional unenhanced and enhanced magnetic resonance imaging (MRI) in other p...

  16. Combination of diffusion tensor imaging and conventional MRI correlates with isocitrate dehydrogenase 1/2 mutations but not 1p/19q genotyping in oligodendroglial tumours

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    Xiong, Ji [Huashan Hospital of Fudan University, Department of Radiology, Shanghai (China); Huashan Hospital of Fudan University, Department of Neuropathology, Shanghai (China); Tan, Wenli [Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Department of Radiology, Shanghai (China); Wen, Jianbo; Pan, Jiawei; Zhang, Jun; Geng, Daoying [Huashan Hospital of Fudan University, Department of Radiology, Shanghai (China); Wang, Yin [Huashan Hospital of Fudan University, Department of Neuropathology, Shanghai (China)

    2016-06-15

    To explore the correlations of conventional MRI (cMRI) and diffusion tensor imaging (DTI) values with the 1p/19 codeletion and IDH mutations in oligodendroglial tumours (OTs). Eighty-four patients with OTs who underwent cMRI and DTI were retrospectively reviewed. The maximal fractional anisotropy and minimal apparent diffusion coefficient (ADC) were measured and compared using the Mann-Whitney U test. Receiver operating characteristic curves, logistic regression analysis and four-table statistics analysis were performed to predict genotypings. OTs with 1p/19q codeletion or IDH mutations were prone to locate in frontal (P = 0.106 and 0.005, respectively) and insular lobes and were associated with absent or blurry contrast enhancement (P = 0.040 and 0.013, respectively). DTI values showed significant differences between OTs with and without IDH mutations (P < 0.05) but not in OTs with and without 1p/19q loss. The Ki-67 index significantly correlated with IDH mutations (P = 0.002) but not with 1p/19q codeletion. A combination of DTI and cMRI for the identification of IDH mutations resulted in sensitivity, specificity, positive and negative predictive values of 92.2 %, 75.8 %, 93.8 % and 71.1 %, respectively. Combination of DTI and cMRI correlates with isocitrate dehydrogenase 1/2 mutations but not 1p/19q genotyping in OTs. (orig.)

  17. Diagnostic accuracy of diffusion-weighted imaging with conventional MR imaging for differentiating complex solid and cystic ovarian tumors at 1.5T

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    Zhang Ping

    2012-11-01

    Full Text Available Abstract Background Preoperative characterization of complex solid and cystic adnexal masses is crucial for informing patients about possible surgical strategies. Our study aims to determine the usefulness of apparent diffusion coefficients (ADC for characterizing complex solid and cystic adnexal masses. Methods One-hundred and 91 patients underwent diffusion-weighted (DW magnetic resonance (MR imaging of 202 ovarian masses. The mean ADC value of the solid components was measured and assessed for each ovarian mass. Differences in ADC between ovarian masses were tested using the Student’s t-test. The receiver operating characteristic (ROC was used to assess the ability of ADC to differentiate between benign and malignant complex adnexal masses. Results Eighty-five patients were premenopausal, and 106 were postmenopausal. Seventy-four of the 202 ovarian masses were benign and 128 were malignant. There was a significant difference between the mean ADC values of benign and malignant ovarian masses (p -3 mm2/s may be the optimal one for differentiating between benign and malignant tumors. Conclusions A high signal intensity within the solid component on T2WI was less frequently in benign than in malignant adnexal masses. The combination of DW imaging with ADC value measurements and T2-weighted signal characteristics of solid components is useful for differentiating between benign and malignant ovarian masses.

  18. Evaluation of the Added Value of Diffusion-Weighted Imaging to Conventional Magnetic Resonance Imaging in Pancreatic Neuroendocrine Tumors and Comparison With 68Ga-DOTANOC Positron Emission Tomography/Computed Tomography.

    Science.gov (United States)

    Farchione, Alessandra; Rufini, Vittoria; Brizi, Maria Gabriella; Iacovazzo, Donato; Larghi, Alberto; Massara, Roberto Maria; Petrone, Gianluigi; Poscia, Andrea; Treglia, Giorgio; De Marinis, Laura; Giordano, Alessandro; Rindi, Guido; Bonomo, Lorenzo

    2016-03-01

    The aims of this study were to investigate the added value of diffusion-weighted imaging (DWI) in pancreatic neuroendocrine tumor (pNET) evaluation and to compare magnetic resonance imaging (MRI) to Ga-DOTANOC positron emission tomography/computed tomography (PET/CT) results. Morphological MRI (T2-weighted [T2-w] + contrast-enhanced [CE] T1-w) and DWI (T2-w + DWI) and Ga-DOTANOC PET/CT in 25 patients/30 pNETs were retrospectively evaluated. Per-patient and per-lesion detection rates (pDR and lDR, respectively) were calculated. Apparent diffusion coefficient values were compared among pNET and surrounding and normal pancreas (control group, 18 patients). Apparent diffusion coefficient and standardized uptake value (SUV) values were compared among different grading and staging groups. No statistically significant differences in PET/CT and MRI session detection rates were found (morphological MRI and DW-MRI, 88% pDR and 87% lDR; combined evaluation, 92% pDR and 90% lDR; Ga-DOTANOC PET/CT, 88% pDR and 80% lDR). Consensus reading (morphological/DW-MRI + PET/CT) improved pDR and lDR (100%). Apparent diffusion coefficient mean value was significantly lower compared with surrounding and normal parenchyma (P < 0.01). The apparent diffusion coefficient and SUV values of pNETs among different grading and staging groups were not statistically different. Conventional MRI, DW-MRI + T2-w sequences, and Ga-DOTANOC PET/CT can be alternative tools in pNET detection. Diffusion-weighted MRI could be valuable in patients with clinical suspicion but negative conventional imaging findings. However, the consensus reading of the 3 techniques seems the best approach.

  19. Liver metastases from colorectal cancer treated with conventional and antiangiogenetic chemotherapy: evaluation with liver computed tomography perfusion and magnetic resonance diffusion-weighted imaging.

    Science.gov (United States)

    Anzidei, Michele; Napoli, Alessandro; Zaccagna, Fulvio; Cartocci, Gaia; Saba, Luca; Menichini, Guendalina; Cavallo Marincola, Beatrice; Marincola, Beatrice Cavallo; Marotta, Eugenio; Di Mare, Luisa; Catalano, Carlo; Passariello, Roberto

    2011-01-01

    The objectives of the study were to determine whether perfusion computed tomography (CT-p) and magnetic resonance diffusion-weighted imaging (MR-DWI) can allow evaluation of the effects of chemotherapy combined with antiangiogenetic treatment on liver metastases in patients with advanced colorectal cancer and to determine if changes in CT-p and MR-DWI correlate with the response to therapy as assessed by conventional Response Evaluation Criteria in Solid Tumors (RECIST). Eighteen patients with liver metastases from colorectal cancer underwent CT-p and MR-DWI before and 6 months after chemotherapy and antiangiogenetic treatment. Lesions were classified according to RECIST criteria (complete response [CR], partial response [PR], stable disease [SD], and progressive disease) and calculations of CT-p parameters including blood flow (BF), blood volume (BV), capillary permeability (CP), and MR-DWI apparent diffusion coefficient (ADC) values were performed; RECIST, CT-p, and MR-DWI measurements at baseline and follow-up were tested for statistically significant differences using the paired-samples t test. Baseline and follow-up perfusion parameters of the lesions were also compared on the basis of therapy response assessed by RECIST criteria using independent-samples t test. P < 0.05 was considered indicative of a statistically significant difference for all statistical test. Six patients (6/18; 33.3%) were classified as PR (), and the remaining 12 (12/18; 66.7%) were classified as SD. On a per-lesion basis, 2 (2/32; 6.3%) cannot be identified at follow-up, 6 (6/32; 18.8%) showed a decrease in size of more than 30%, and 24 (24/32; 75%) were substantially stable in size. No cases of progressive disease were demonstrated at follow-up. No statistically significant differences were demonstrated between PR, CR, and SD lesions for BF (P = 0.19), BV (P = 0.14), and ADC (P = 0.68) measurements, whereas CP was significantly higher in CR and PR lesions (P = 0.038). Considering

  20. Intravoxel Incoherent Motion Diffusion Weighted MR Imaging for Monitoring the Instantly Therapeutic Efficacy of Radiofrequency Ablation in Rabbit VX2 Tumors without Evident Links between Conventional Perfusion Weighted Images.

    Directory of Open Access Journals (Sweden)

    Ziyi Guo

    Full Text Available To investigate the intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI as a potential valuable marker to monitor the therapy responses of VX2 to radiofrequency ablation (RF Ablation.The institutional animal care and use committee approved this study. In 10 VX2 tumor-bearing rabbits, IVIM-DWI examinations were performed with a 3.0T imaging unit by using 16 b values from 0 to 800 sec/mm2. The true diffusion coefficient (D, pseudodiffusion coefficient (D* and perfusion fraction (f of tumors were compared between before and instantly after RF Ablation treatment. The differences of D, D* and f and conventional perfusion parameters (from perfusion CT and dynamic enhanced magnetic resonance imaging, DCE-MRI in the coagulation necrosis area, residual unablated area, untreated area, and normal control had been calculated by compared t-test. The correlation between f or D* with perfusion weighted CT including blood flow, BF (milliliter per 100 mL/min, blood volume, BV (milliliter per 100 mL/min, and capillary permeability-surface area, PMB (as a fraction or from DCE-MRI: transfer constant (Ktrans, extra-vascular extra-cellular volume fraction (Ve and reflux constant (Kep values had been analyzed by region-of-interest (ROI methods to calculate Pearson's correlation coefficients.In the ablated necrosis areas, f and D* significantly decreased and D significantly increased, compared with residual unblazed areas or untreated control groups and normal control groups (P < 0.001. The IVIM-DWI derived f parameters showed significant increases in the residual unablated tumor area. There was no significant correlations between f or D* and conventional perfusion parameters.The IVIM-DW derived f, D and D* parameters have the potential to indicate therapy response immediately after RF Ablation treatment, while no significant correlations with classical tumor perfusion metrics were derived from DCE-MRI and perfusion-CT measurements.

  1. Diffusion Weighted and Trace Images

    Directory of Open Access Journals (Sweden)

    Helen Nayeri

    2009-01-01

    completely restricted. For example, myelin fiber and neurofibril orientation in white matter possesses a preferred direction for water proton movement. The rate of water diffusion varies with direction due to biological constrains. This feature causes protons to diffuse faster along the path of least resistance, causing the ADC to be anisotropic, or directionally dependent. The orientation of the anisotropy is correlated to the direction of the tract of myelinated axons. In the cerebral cortex, there are three whit matter tracts; 1. Association; 2. Projection; and 3.commissural, that are oriented in different directions. In order to have an isotropic or trace image, DWIs are sensitized in the X-Y-and Z directions. The signal intensity in each voxel is the average of the other three images, thereby minimizing anisotropic nature of the biological medium and delineating the affected area. While it is of interest to minimize diffusion anisotropy in stroke imaging, the ability to detect anisotropic differences is useful for the study of normal anatomy and white matter pathology. "nDWI has become a standard part of the diagnostic work-up of intracranial pathology. "nDue to increased sensitivity of DWI for detecting ischemic changes in the hyperacute time period (restricted diffusion because of cytotoxic edema; it has emerged as the gold standard for acute ischemic stroke diagnosis. The particular advantage of this technique is the delineation of potential tissue at risk; the aim for most therapeutic efforts. In addition to providing information about lesion location, volume, and vascular distribution, DWI allows characterization of lesion evolution using the change in the ADC. Using only conventional imaging and clinical symptoms the distinction of an abscess from a cystic or necrotic tumor is difficult. It has been shown that such distinction would be more reliably made using DWI and ADC values. Due to highly viscous combination of inflammatory cell, debris, and bacteria in a

  2. Diffusion tensor tractography as a supplementary tool to conventional MRI for evaluating patients with myelopathy

    Directory of Open Access Journals (Sweden)

    Amal Amin A. El Maati

    2014-12-01

    Conclusion: Diffusion tensor imaging is a reliable method for the evaluation of the diffusion properties of normal and compressed spinal cords. Furthermore, this technique can be used as an important supplementary tool to conventional MRI for the quantification of fiber damage in spinal cord compression, thus has the potential to be of great utility for treatment planning and follow up.

  3. 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.)

  4. Interpolation of diffusion weighted imaging datasets

    DEFF Research Database (Denmark)

    Dyrby, Tim B; Lundell, Henrik; Burke, Mark W

    2014-01-01

    Diffusion weighted imaging (DWI) is used to study white-matter fibre organisation, orientation and structural connectivity by means of fibre reconstruction algorithms and tractography. For clinical settings, limited scan time compromises the possibilities to achieve high image resolution for finer...... anatomical details and signal-to-noise-ratio for reliable fibre reconstruction. We assessed the potential benefits of interpolating DWI datasets to a higher image resolution before fibre reconstruction using a diffusion tensor model. Simulations of straight and curved crossing tracts smaller than or equal...... to the voxel size showed that conventional higher-order interpolation methods improved the geometrical representation of white-matter tracts with reduced partial-volume-effect (PVE), except at tract boundaries. Simulations and interpolation of ex-vivo monkey brain DWI datasets revealed that conventional...

  5. Conventions and nomenclature for double diffusion encoding NMR and MRI

    DEFF Research Database (Denmark)

    Shemesh, Noam; Jespersen, Sune N; Alexander, Daniel C;

    2015-01-01

    Stejskal and Tanner's ingenious pulsed field gradient design from 1965 has made diffusion NMR and MRI the mainstay of most studies seeking to resolve microstructural information in porous systems in general and biological systems in particular. Methods extending beyond Stejskal and Tanner's desig...... to the standard, macroscopic, fractional anisotropy conventionally obtained by diffusion MR. Finally, we discuss future vistas and perspectives for DDE. Magn Reson Med, 2015. © 2015 Wiley Periodicals, Inc....

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

    Energy Technology Data Exchange (ETDEWEB)

    Server, A.; Nakstad, P.Hj.; Dullerud, R.; Haakonsen, M. [Ullevaal Univ. Hospital, Oslo (Norway). Dept. of Neuroradiology; Hovda, K.E.; Jacobsen, D. [Ullevaal Univ. Hospital, Oslo (Norway). Dept. of Medicine

    2003-11-01

    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.

  7. Predicting Treatment Response of Colorectal Cancer Liver Metastases to Conventional Lipiodol-Based Transarterial Chemoembolization Using Diffusion-Weighted MR Imaging: Value of Pretreatment Apparent Diffusion Coefficients (ADC) and ADC Changes Under Therapy.

    Science.gov (United States)

    Lahrsow, Maximilian; Albrecht, Moritz H; Bickford, Matthew W; Vogl, Thomas J

    2017-06-01

    To use absolute pretreatment apparent diffusion coefficients (ADC) derived from diffusion-weighted MR imaging (DWI) to predict response to repetitive cTACE for unresectable liver metastases of colorectal carcinoma (CRLM) at 1 and 3 months after start of treatment. Fifty-five metastases in 34 patients were examined with DWI prior to treatment and 1 month after initial cTACE. Treatment was performed in 4-week intervals. Response was evaluated at 1 and 3 months after start of therapy. Metastases showing a decrease of ≥30% in axial diameter were classified as responding lesions. One month after initial cTACE, seven lesions showed early response. There was no significant difference in absolute pretreatment ADC values between responding and non-responding lesions (p = 0.94). Three months after initial cTACE, 17 metastases showed response. There was a significant difference (p = 0.021) between absolute pretreatment ADC values of lesions showing response (median 1.08 × 10(-3) mm(2)/s) and no response (median 1.30 × 10(-3) mm(2)/s). Pretreatment ADC showed fair diagnostic value to predict response (AUC 0.7). Lesions showing response at 3 months also revealed a significant increase in ADC between measurements before treatment and at one month after initial cTACE (p < 0.001). Applying an increase in ADC of 12.17%, response at 3 months after initial cTACE could be predicted with a sensitivity and specificity of 77 and 74%, respectively (AUC 0.817). Furthermore, there was a strong and significant correlation (r = 0.651, p < 0.001) between percentage change in size after third cTACE and percentage change in ADC. In patients with CRLM, ADC measurements are potential biomarkers for assessing response to cTACE.

  8. "Conventional" CT images from spectral measurements

    Science.gov (United States)

    Rajbhandary, Paurakh L.; Pelc, Norbert J.

    2016-03-01

    Spectral imaging systems need to be able to produce "conventional" images, and it's been shown that systems with energy discriminating detectors can achieve higher CNR than conventional systems by optimal weighting. Combining measured data in energy bins (EBs) and also combining basis material images have previously been proposed, but there are no studies systematically comparing the two methods. In this paper, we analytically evaluate the two methods for systems with ideal photon counting detectors using CNR and beam hardening (BH) artifact as metrics. For a 120-kVp polychromatic simulations of a water phantom with low contrast inserts, the difference of the optimal CNR between the two methods for the studied phantom is within 2%. For a polychromatic spectrum, beam-hardening artifacts are noticeable in EB weighted images (BH artifact of 3.8% for 8 EB and 6.9% for 2 EB), while weighted basis material images are free of such artifacts.

  9. Diffusion weighted imaging in the liver

    NARCIS (Netherlands)

    Kele, Petra G.; van der Jagt, Eric J.

    2010-01-01

    Diffusion weighted magnetic resonance imaging (DWI) is an imaging technique which provides tissue contrast by the measurement of diffusion properties of water molecules within tissues. Diffusion is expressed in an apparent diffusion coefficient (ADC), which reflects the diffusion properties unique t

  10. Various diffusion magnetic resonance imaging techniques for pancreatic cancer

    Institute of Scientific and Technical Information of China (English)

    Meng-Yue Tang; Xiao-Ming Zhang; Tian-Wu Chen; Xiao-Hua Huang

    2015-01-01

    Pancreatic cancer is one of the most common malignanttumors and remains a treatment-refractory cancer with a poor prognosis. Currently, the diagnosis of pancreatic neoplasm depends mainly on imaging and which methods are conducive to detecting small lesions. Compared to the other techniques, magnetic resonance imaging(MRI) has irreplaceable advantages and can provide valuable information unattainable with other noninvasive or minimally invasive imaging techniques. Advances in MR hardware and pulse sequence design have particularly improved the quality and robustness of MRI of the pancreas. Diffusion MR imaging serves as one of the common functional MRI techniques and is the only technique that can be used to reflect the diffusion movement of water molecules in vivo. It is generally known that diffusion properties depend on the characterization of intrinsic features of tissue microdynamics and microstructure. With the improvement of the diffusion models, diffusion MR imaging techniques are increasingly varied, from the simplest and most commonly used technique to the more complex. In this review, the various diffusion MRI techniques for pancreatic cancer are discussed, including conventional diffusion weighted imaging(DWI), multi-b DWI based on intra-voxel incoherent motion theory, diffusion tensor imaging and diffusion kurtosis imaging. The principles, main parameters, advantages and limitations of these techniques, as well as future directions for pancreatic diffusion imaging are also discussed.

  11. Myelin water weighted diffusion tensor imaging.

    Science.gov (United States)

    Avram, Alexandru V; Guidon, Arnaud; Song, Allen W

    2010-10-15

    In this study we describe our development and implementation of a magnetization transfer (MT) prepared stimulated-echo diffusion tensor imaging (DTI) technique that can be made sensitive to the microanatomy of myelin tissue. The short echo time (TE) enabled by the stimulated-echo acquisition preserves significant signal from the short T(2) component (myelin water), and the MT preparation further provides differentiating sensitization to this signal. It was found that this combined strategy could provide sufficient sensitivity in our first attempt to image myelin microstructure. Compared to the diffusion tensor derived from the conventional DTI technique, the myelin water weighted (MWW) tensor has the same principal diffusion direction but exhibits a significant increase in fractional anisotropy (FA), which is mainly due to a decrease in radial diffusivity. These findings are consistent with the microstructural organization of the myelin sheaths that wrap around the axons in the white matter and therefore hinder radial diffusion. Given that many white matter diseases (e.g. multiple sclerosis) begin with a degradation of myelin microanatomy but not a loss of myelin content (e.g. loosening of the myelin sheaths), our newly implemented MWW DTI has the potential to lead to improved assessment of myelin pathology and early detection of demyelination.

  12. Diffusion-weighted imaging of pancreatic cancer

    Institute of Scientific and Technical Information of China (English)

    Riccardo; De; Robertis; Paolo; Tinazzi; Martini; Emanuele; Demozzi; Flavia; Dal; Corso; Claudio; Bassi; Paolo; Pederzoli; Mirko; D’Onofrio

    2015-01-01

    Magnetic resonance imaging(MRI) is a reliable and accurate imaging method for the evaluation of patients with pancreatic ductal adenocarcinoma(PDAC). Diffusion-weighted imaging(DWI) is a relatively recent technological improvement that expanded MRI capabilities, having brought functional aspects into conventional morphologic MRI evaluation. DWI can depict the random diffusion of water molecules within tissues(the so-called Brownian motions). Modifications of water diffusion induced by different factors acting on the extracellular and intracellular spaces, as increased cell density, edema, fibrosis, or altered functionality of cell membranes, can be detected using this MR sequence. The intravoxel incoherent motion(IVIM) model is an advanced DWI technique that consent a separate quantitative evaluation of all the microscopic random motions that contribute to DWI, which are essentially represented by molecular diffusion and blood microcirculation(perfusion). Technological improvements have made possible the routine use of DWI during abdominal MRI study. Several authors have reported that the addition of DWI sequence can be of value for the evaluation of patients with PDAC, especially improving the staging; nevertheless, it is still unclear whether and how DWI could be helpful for identification, characterization, prognostic stratification and follow-up during treatment. The aim of this paper is to review up-to-date literature data regarding the applications of DWI and IVIM to PDACs.

  13. Interpolation of diffusion weighted imaging datasets.

    Science.gov (United States)

    Dyrby, Tim B; Lundell, Henrik; Burke, Mark W; Reislev, Nina L; Paulson, Olaf B; Ptito, Maurice; Siebner, Hartwig R

    2014-12-01

    Diffusion weighted imaging (DWI) is used to study white-matter fibre organisation, orientation and structural connectivity by means of fibre reconstruction algorithms and tractography. For clinical settings, limited scan time compromises the possibilities to achieve high image resolution for finer anatomical details and signal-to-noise-ratio for reliable fibre reconstruction. We assessed the potential benefits of interpolating DWI datasets to a higher image resolution before fibre reconstruction using a diffusion tensor model. Simulations of straight and curved crossing tracts smaller than or equal to the voxel size showed that conventional higher-order interpolation methods improved the geometrical representation of white-matter tracts with reduced partial-volume-effect (PVE), except at tract boundaries. Simulations and interpolation of ex-vivo monkey brain DWI datasets revealed that conventional interpolation methods fail to disentangle fine anatomical details if PVE is too pronounced in the original data. As for validation we used ex-vivo DWI datasets acquired at various image resolutions as well as Nissl-stained sections. Increasing the image resolution by a factor of eight yielded finer geometrical resolution and more anatomical details in complex regions such as tract boundaries and cortical layers, which are normally only visualized at higher image resolutions. Similar results were found with typical clinical human DWI dataset. However, a possible bias in quantitative values imposed by the interpolation method used should be considered. The results indicate that conventional interpolation methods can be successfully applied to DWI datasets for mining anatomical details that are normally seen only at higher resolutions, which will aid in tractography and microstructural mapping of tissue compartments.

  14. Diffusion Tensor Imaging: Exploring the Motor Networks and Clinical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sung Soo; Lee, Seung Koo [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2011-11-15

    With the advances in diffusion magnetic resonance (MR) imaging techniques, diffusion tensor imaging (DTI) has been applied to a number of neurological conditions because DTI can demonstrate microstructures of the brain that are not assessable with conventional MR imaging. Tractography based on DTI offers gross visualization of the white matter fiber architecture in the human brain in vivo. Degradation of restrictive barriers and disruption of the cytoarchitecture result in changes in the diffusion of water molecules in various pathological conditions, and these conditions can also be assessed with DTI. Yet many factors may influence the ability to apply DTI clinically, so these techniques have to be used with a cautious hand.

  15. Image denoising using modified nonlinear diffusion approach

    Science.gov (United States)

    Upadhyay, Akhilesh R.; Talbar, Sanjay N.; Sontakke, Trimbak R.

    2006-01-01

    Partial Differential Equation (PDE) based, non-linear diffusion approaches are an effective way to denoise the images. In this paper, the work is extended to include anisotropic diffusion, where the diffusivity is a tensor valued function, which can be adapted to local edge orientation. This allows smoothing along the edges, but not perpendicular to it. The diffusion tensor is a function of differential structure of the evolving image itself. Such a feedback leads to nonlinear diffusion filters. It shows improved performance in the presence of noise. The original anisotropic diffusion algorithm updates each point based on four nearest-neighbor differences, the progress of diffusion results in improved edges. In the proposed method the edges are better preserved because diffusion is controlled by the gray level differences of diagonal neighbors in addition to 4 nearest neighbors using coupled PDF formulation. The proposed algorithm gives excellent results for MRI images, Biomedical images and Fingerprint images with noise.

  16. Diffusion kurtosis imaging can efficiently assess the glioma grade and cellular proliferation

    OpenAIRE

    Jiang, Rifeng; Jiang, Jingjing; Zhao, Lingyun; Zhang, Jiaxuan; Zhang, Shun; Yao, Yihao; Yang, Shiqi; Shi, Jingjing; Shen, Nanxi; Su, Changliang; Zhang, Ju; Zhu, Wenzhen

    2015-01-01

    Conventional diffusion imaging techniques are not sufficiently accurate for evaluating glioma grade and cellular proliferation, which are critical for guiding glioma treatment. Diffusion kurtosis imaging (DKI), an advanced non-Gaussian diffusion imaging technique, has shown potential in grading glioma; however, its applications in this tumor have not been fully elucidated. In this study, DKI and diffusion weighted imaging (DWI) were performed on 74 consecutive patients with histopathologicall...

  17. Diffusion-weighted and diffusion-tensor imaging of normal and diseased uterus

    Institute of Scientific and Technical Information of China (English)

    Duygu; Kara; Bozkurt; Murat; Bozkurt; Mehmet; Ali; Nazli; Ilhan; Nahit; Mutlu; Ozgur; Kilickesmez

    2015-01-01

    Owing to technical advances and improvement of the software, diffusion weighted imaging and diffusion tensor imaging(DWI and DTI) greatly improved the diagnostic value of magnetic resonance imaging(MRI) of the pelvic region. These imaging sequences can exhibit important tissue contrast on the basis of random diffusion(Brownian motion) of water molecules in tissues. Quantitative measurements can be done with DWI and DTI by apparent diffusion coefficient(ADC) and fractional anisotropy(FA) values respectively. ADC and FA values may be changed by various physiological and pathological conditions providing additional information to conventional MRI. The quantitative DWI assists significantly in the differentiation of benign and malignant lesions. It can demonstrate the microstructural architecture and celluler density of the normal and diseased uterine zones. On the other hand, DWI and DTI are useful for monitoring the treatment outcome of the uterine lesions. In this review, we discussed advantages of DWI and DTI of the normal and diseased uterus.

  18. Conventional and advanced imaging in neuromyelitis optica.

    Science.gov (United States)

    Barnett, Y; Sutton, I J; Ghadiri, M; Masters, L; Zivadinov, R; Barnett, M H

    2014-08-01

    Myelitis and optic neuritis are prototypic clinical presentations of both multiple sclerosis and neuromyelitis optica. Once considered a subtype of multiple sclerosis, neuromyelitis optica, is now known to have a discrete pathogenesis in which antibodies to the water channel, aquaporin 4, play a critical role. Timely differentiation of neuromyelitis optica from MS is imperative, determining both prognosis and treatment strategy. Early, aggressive immunosuppression is required to prevent the accrual of severe disability in neuromyelitis optica; conversely, MS-specific therapies may exacerbate the disease. The diagnosis of neuromyelitis optica requires the integration of clinical, MR imaging, and laboratory data, but current criteria are insensitive and exclude patients with limited clinical syndromes. Failure to recognize the expanding spectrum of cerebral MR imaging patterns associated with aquaporin 4 antibody seropositivity adds to diagnostic uncertainty in some patients. We present the state of the art in conventional and nonconventional MR imaging in neuromyelitis optica and review the place of neuroimaging in the diagnosis, management, and research of the condition.

  19. Comparative analysis of isotropic diffusion weighted imaging sequences

    Science.gov (United States)

    Vellmer, Sebastian; Stirnberg, Rüdiger; Edelhoff, Daniel; Suter, Dieter; Stöcker, Tony; Maximov, Ivan I.

    2017-02-01

    Visualisation of living tissue structure and function is a challenging problem of modern imaging techniques. Diffusion MRI allows one to probe in vivo structures on a micrometer scale. However, conventional diffusion measurements are time-consuming procedures, because they require several measurements with different gradient directions. Considerable time savings are therefore possible by measurement schemes that generate an isotropic diffusion weighting in a single shot. Multiple approaches for generating isotropic diffusion weighting are known and have become very popular as useful tools in clinical research. Thus, there is a strong need for a comprehensive comparison of different isotropic weighting approaches. In the present work we introduce two new sequences based on simple (co)sine modulations and compare their performance to established q-space magic-angle spinning sequences and conventional DTI, using a diffusion phantom assembled from microcapillaries and in vivo experiments at 7 T. The advantages and disadvantages of all compared schemes are demonstrated and discussed.

  20. Comparing near-infrared conventional diffuse reflectance spectroscopy and hyperspectral imaging for determination of the bulk properties of solid samples by multivariate regression: determination of Mooney viscosity and plasticity indices of natural rubber.

    Science.gov (United States)

    Juliano da Silva, Carlos; Pasquini, Celio

    2015-01-21

    Conventional reflectance spectroscopy (NIRS) and hyperspectral imaging (HI) in the near-infrared region (1000-2500 nm) are evaluated and compared, using, as the case study, the determination of relevant properties related to the quality of natural rubber. Mooney viscosity (MV) and plasticity indices (PI) (PI0 - original plasticity, PI30 - plasticity after accelerated aging, and PRI - the plasticity retention index after accelerated aging) of rubber were determined using multivariate regression models. Two hundred and eighty six samples of rubber were measured using conventional and hyperspectral near-infrared imaging reflectance instruments in the range of 1000-2500 nm. The sample set was split into regression (n = 191) and external validation (n = 95) sub-sets. Three instruments were employed for data acquisition: a line scanning hyperspectral camera and two conventional FT-NIR spectrometers. Sample heterogeneity was evaluated using hyperspectral images obtained with a resolution of 150 × 150 μm and principal component analysis. The probed sample area (5 cm(2); 24,000 pixels) to achieve representativeness was found to be equivalent to the average of 6 spectra for a 1 cm diameter probing circular window of one FT-NIR instrument. The other spectrophotometer can probe the whole sample in only one measurement. The results show that the rubber properties can be determined with very similar accuracy and precision by Partial Least Square (PLS) regression models regardless of whether HI-NIR or conventional FT-NIR produce the spectral datasets. The best Root Mean Square Errors of Prediction (RMSEPs) of external validation for MV, PI0, PI30, and PRI were 4.3, 1.8, 3.4, and 5.3%, respectively. Though the quantitative results provided by the three instruments can be considered equivalent, the hyperspectral imaging instrument presents a number of advantages, being about 6 times faster than conventional bulk spectrometers, producing robust spectral data by ensuring sample

  1. Diffusion tensor imaging for brain malformations: does it help?

    Science.gov (United States)

    Huisman, Thierry A G M; Bosemani, Thangamadhan; Poretti, Andrea

    2014-11-01

    In this article, the basics of diffusion-weighted imaging/diffusion tensor imaging (DTI) are discussed, including a short historical perspective on the fiber dissection technique, followed by a review of selected brain malformations in which DTI and tractography have contributed to a better understanding of the malformations, and by a clinical case in which DTI showed a disorder of the internal neuroarchitecture that could not be correctly appreciated by conventional anatomic magnetic resonance imaging. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Diffusion Tensor Imaging of Pedophilia.

    Science.gov (United States)

    Cantor, James M; Lafaille, Sophie; Soh, Debra W; Moayedi, Massieh; Mikulis, David J; Girard, Todd A

    2015-11-01

    Pedophilia is a principal motivator of child molestation, incurring great emotional and financial burdens on victims and society. Even among pedophiles who never commit any offense,the condition requires lifelong suppression and control. Previous comparison using voxel-based morphometry (VBM)of MR images from a large sample of pedophiles and controls revealed group differences in white matter. The present study therefore sought to verify and characterize white matter involvement using diffusion tensor imaging (DTI), which better captures the microstructure of white matter than does VBM. Pedophilics ex offenders (n=24) were compared with healthy, age-matched controls with no criminal record and no indication of pedophilia (n=32). White matter microstructure was analyzed with Tract-Based Spatial Statistics, and the trajectories of implicated fiber bundles were identified by probabilistic tractography. Groups showed significant, highly focused differences in DTI parameters which related to participants’ genital responses to sexual depictions of children, but not to measures of psychopathy or to childhood histories of physical abuse, sexual abuse, or neglect. Some previously reported gray matter differences were suggested under highly liberal statistical conditions (p(uncorrected)<.005), but did not survive ordinary statistical correction (whole brain per voxel false discovery rate of 5%). These results confirm that pedophilia is characterized by neuroanatomical differences in white matter microstructure, over and above any neural characteristics attributable to psychopathy and childhood adversity, which show neuroanatomic footprints of their own. Although some gray matter structures were implicated previously, only few have emerged reliably.

  3. Modified anisotropic diffusion for image smoothing and enhancement

    Science.gov (United States)

    Tang, Zhong; Whitaker, Ross T.

    2001-05-01

    This paper discusses an improved nonlinear filtering approach based on anisotropic diffusion technique. This modified anisotropic diffusion method smooths along curve directions, i.e. the directions of level sets. The upwind scheme for level set is used to solve the diffusion equation. Compared with the conventional anisotropic diffusion, which depends only on the local gradient of intensities of the processed image, this modified scheme overcomes the defect of indefinite edge enhancement associated with Perona-Malik model while depressing noises in a better performance. Moreover, a multi-scale diffusion technique is applied to limit blurring by the presence of edges as measured at the scale of interest, so that accurate information about boundaries of objects could be preserved and small details that fall below the scale of interest be removed. Then an extension into vector-valued diffusion is also presented in this paper, which is capable of smoothing small objects while maintaining boundaries information in vector-valued images. Experiments on gray-scale and color images demonstrate the efficacy of this method in image smoothing as well as image enhancement.

  4. Basic principles of diffusion-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bammer, Roland. E-mail: roland@s-word.stanford.edu

    2003-03-01

    In diffusion-weighted MRI (DWI), image contrast is determined by the random microscopic motion of water protons. During the last years, DWI has become an important modality in the diagnostic work-up of acute ischemia in the CNS. There are also a few promising reports about the application of DWI to other regions in the human body, such as the vertebral column or the abdomen. This manuscript provides an introduction into the basics of DWI and Diffusion Tensor imaging. The potential of various MR sequences in concert with diffusion preparation are discussed with respect to acquisition speed, spatial resolution, and sensitivity to bulk physiologic motion. More advanced diffusion measurement techniques, such as high angular resolution diffusion imaging, are also addressed.

  5. Diffusion Pore Imaging by Hyperpolarized Xenon-129 Nuclear Magnetic Resonance

    CERN Document Server

    Kuder, Tristan Anselm; Windschuh, Johannes; Laun, Frederik Bernd

    2012-01-01

    Nuclear magnetic resonance (NMR) diffusion measurements are widely used to derive parameters indirectly related to the microstructure of biological tissues and porous media. However, a direct imaging of cell or pore shapes and sizes would be of high interest. For a long time, determining pore shapes by NMR diffusion acquisitions seemed impossible, because the necessary phase information could not be preserved. Here we demonstrate experimentally using the measurement technique which we have recently proposed theoretically that the shape of arbitrary closed pores can be imaged by diffusion acquisitions, which yield the phase information. For this purpose, we use hyperpolarized xenon gas in well-defined geometries. The signal can be collected from the whole sample which mainly eliminates the problem of vanishing signal at increasing resolution of conventional NMR imaging. This could be used to non-invasively gain structural information inaccessible so far such as pore or cell shapes, cell density or axon integri...

  6. Substitution-diffusion based Image Cipher

    Directory of Open Access Journals (Sweden)

    Narendra K Pareek

    2011-03-01

    Full Text Available In this paper, a new image encryption scheme using a secret key of 128-bit size is proposed. In thealgorithm, image is partitioned into several key based dynamic blocks and further, each block passesthrough the eight rounds of diffusion as well as substitution process. In diffusion process, sequences ofblock pixels are rearranged within the block by a zigzag approach whereas block pixels are replaced withanother by using difference calculation of row and column in substitution process. Due to high order ofsubstitution and diffusion, common attacks like linear and differential cryptanalysis are infeasible. Theexperimental results show that the proposed technique is efficient and has high security features.

  7. Robust diffusion imaging framework for clinical studies

    CERN Document Server

    Maximov, Ivan I; Neuner, Irene; Shah, N Jon

    2015-01-01

    Clinical diffusion imaging requires short acquisition times and good image quality to permit its use in various medical applications. In turn, these demands require the development of a robust and efficient post-processing framework in order to guarantee useful and reliable results. However, multiple artefacts abound in in vivo measurements; from either subject such as cardiac pulsation, bulk head motion, respiratory motion and involuntary tics and tremor, or imaging hardware related problems, such as table vibrations, etc. These artefacts can severely degrade the resulting images and render diffusion analysis difficult or impossible. In order to overcome these problems, we developed a robust and efficient framework enabling the use of initially corrupted images from a clinical study. At the heart of this framework is an improved least trimmed squares diffusion tensor estimation algorithm that works well with severely degraded datasets with low signal-to-noise ratio. This approach has been compared with other...

  8. Image Magnification Method Using Joint Diffusion

    Institute of Scientific and Technical Information of China (English)

    Zhong-Xuan Liu; Hong-Jian Wang; Si-Long Peng

    2004-01-01

    In this paper a new algorithm for image magnification is presented. Because linear magnification/interpolation techniques diminish the contrast and produce sawtooth effects, in recent years, many nonlinear interpolation methods, especially nonlinear diffusion based approaches, have been proposed to solve these problems. Two recently proposed techniques for interpolation by diffusion, forward and backward diffusion (FAB) and level-set reconstruction (LSR), cannot enhance the contrast and smooth edges simultaneously. In this article, a novel Partial Differential Equations (PDE) based approach is presented. The contributions of the paper include:firstly, a unified form of diffusion joining FAB and LSR is constructed to have all of their virtues; secondly, to eliminate artifacts of the joint diffusion, soft constraint takes the place of hard constraint presented by LSR;thirdly, the determination of joint coefficients, criterion for stopping time and color image processing are also discussed. The results demonstrate that the method is visually and quantitatively better than Bicubic, FAB and LSR.

  9. Quaternion Diffusion for Color Image Filtering

    Institute of Scientific and Technical Information of China (English)

    Zhong-Xuan Liu; Shi-Guo Lian; Zhen Ren

    2006-01-01

    How to combine color and multiscale information is a fundamental question for computer vision, and quite a few color diffusion techniques have been presented. Most of these proposed techniques do not consider the direct interactions between color channel pairs. In this paper, a new method of color diffusion considering these effects is presented, which is based on quaternion diffusion (QD) equation. In addition to showing the solution to linear QD and its analysis, one form of nonlinear QD is discussed. Compared with other color diffusion techniques, considering the interactions between channel pairs, QD has the following advantages: 1) staircasing effect is avoided; 2) as diffusion tensor, the image derivative is regu larized without requiring additional convolution; 3) less time is needed. Experimental results demonstrate the effectiveness of linear and nonlinear QD applied to natural color images for denoising by both visual and quantitative evaluations.

  10. Evaluation of digital halftones image by vector error diffusion

    Science.gov (United States)

    Kouzaki, Masahiro; Itoh, Tetsuya; Kawaguchi, Takayuki; Tsumura, Norimichi; Haneishi, Hideaki; Miyake, Yoichi

    1998-12-01

    The vector error diffusion (VED) method is applied to proudce the digital halftone images by an electrophotographic printer with 600 dpi. Objective image quality of those obtained images is evaluated and analyzed. As a result, in the color reproduction of halftone image by the VED method, it was clear that there are large color difference between target color and printed color typically in the mid-tone colors. We consider it is due to the printer properties including dot-gain. It was also clear that the color noise of the VED method is larger compared with that of the conventional scalar error diffusion method in some patches. It was remarkable that ununiform patterns are generated by the VED method.

  11. Magnetic resonance diffusion-weighted imaging in the diagnosis of diffuse liver diseases in rats

    Institute of Scientific and Technical Information of China (English)

    GUAN Sheng; ZHOU Kang-rong; ZHAO Wei-dong; PENG Wei-jun; TANG Feng; MAO Jian

    2005-01-01

    Background The diagnosis of diffuse hepatic lesions in early stage is a tough task at any time for clinical conventional imaging Magnetic resonance diffusion-weighted imaging (MR DWI) can detect the changes of tissue structure at molecular level This study was designed to determine the value of DWI in the diagnosis of diffuse liver lesions in early stage.Methods Diffuse liver lesions were induced by diethylnitrosamine in 42 rats of test group. Fourteen rats in control group were fed with pure water. Dynamic changes of MR DWI were observed every week in both groups during the early stage of diffuse liver lesions (1 to 12 weeks after drug administration in the test group). Apparent diffusion coefficient (ADC) values of liver parenchyma in different stages and pathologic changes were analyzed.Results The process of diffuse hepatic lesions in the test group was classified into three stages according to pathological changes, namely hepatitis, hepatic fibrosis and cirrhosis. No obvious morphological changes were shown by conventional imaging in both groups during this stage. But MR DWI demonstrated heterogeneous signal changes in early stage of hepatic cirrhosis in the test group. No significant change of ADC values was found in the control group between different weeks (P>0.05). The ADC values of the test group declined from the fifth week, and after the tenth week the ADC values were significantly different between the test and control groups at gradient factor (b) value 300 sec/mm2 (P<0.05). At b value 600 and 1000 sec/mm2, significant difference was seen between the two groups from the sixth week onward. The range of ADC value of the groups was (1.7-0.9)±(0.40-0.04) mm2/sec (b=600) and (1.38-0.75)±(0.07-0.35) mm2/sec (b=1000), respectively. Dominant pathological changes included swelled hepatocytes within 1 to 4 weeks after the administration of diethylnitrosamine in the test group, hyperplasia of fibrous tissues in 5-8 weeks and formation of cirrhotic nodules in 9

  12. 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...

  13. Comparison of the diagnostic performances of diffusion parameters in diffusion weighted imaging and diffusion tensor imaging of breast lesions

    Energy Technology Data Exchange (ETDEWEB)

    Cakir, Ozgur, E-mail: cakirozgur@hotmail.com; Arslan, Arzu, E-mail: arzu.s.arslan@gmail.com; Inan, Nagihan, E-mail: nagihaninan@yahoo.com.tr; Anık, Yonca, E-mail: yoncaanik@yahoo.com; Sarısoy, Tahsin, E-mail: htsarisoy@yahoo.com; Gumustas, Sevtap, E-mail: svtgumustas@yahoo.com; Akansel, Gur, E-mail: gakansel@gmail.com

    2013-12-01

    Purpose: To evaluate the diagnostic efficiency of the diffusion parameters measured by conventional diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) for discrimination of malignant breast lesions from benign lesions and the normal breast. Materials and methods: The study included 52 women with 55 breast lesions (30 malignant, 25 benign). DTI and DWI were performed complementary to dynamic contrast MRI at 3T. Apparent diffusion coefficient (ADC) of DWI, mean diffusivity (MD) and fractional anisotropy (FA) values of DTI were measured for lesions and contralateral breast parenchyma in each patient. We used b factors of 0, 50, 850, 1000 and 1500 s/mm{sup 2} for DWI and b 0 and 1000 s/mm{sup 2} for DTI. ADC, MD and FA values were compared between malignant and benign lesions, and the normal parenchyma by univariate and multivariate analyses. Results: Diffusion parameters showed no difference according to menopausal status in the normal breast. ADC and MD values of the malignant lesions were significantly lower than benign lesions and normal parenchyma (p = 0.001). The FA showed no statistical significance. With the cut-off values of ≤1.23 × 10{sup −3} mm{sup 2}/s (b 0–1000 s/mm{sup 2}) and ≤1.12 × 10{sup −3} mm{sup 2}/s (b 0–1500 s/mm{sup 2}), ADC showed 92.85% and 96.15% sensitivity; 72.22% and 73.52% PPV, respectively. With a cut-off value of ≤1.27 × 10{sup −3} mm{sup 2}/s (b 1000 s/mm{sup 2}), MD was 100% sensitive with a PPV of 65.90%. Comparing the diagnostic performance of the parameters in DTI with DWI, we obtained similar efficiency of ADC with b values of 0,1000 and 0,1500 s/mm{sup 2} and MD with a b value of 0, 1000 s/mm{sup 2} (AUC = 0.82 ± 0.07). Conclusion: ADC of DWI and MD of DTI values provide significant discriminative factors for benign and malignant breast lesions. FA measurement was not discriminative. Supported with clinical and dynamic contrast MRI findings, DWI and DTI findings provide significant

  14. Diffusion tensor imaging with multiple diffusion-weighted gradient directions

    Institute of Scientific and Technical Information of China (English)

    Shan Jiang; Meixia Liu; Tong Han; Weihua Liu

    2011-01-01

    Diffusion tensor MRI (DT-MRI or DTI) is emerging as an important non-invasive technology for elucidating internal brain structures.It has recently been utilized to diagnose a series of diseases that affect the integrity of neural systems to provide a basis for neuroregenerative studies.Results from the present study suggested that neural tissue is reconstructed with multiple diffusion-weighted gradient directions DTI,which varies from traditional imaging methods that utilize 6 gradient directions.Simultaneously,the diffusion tensor matrix is obtained by multiple linear regressions from an equation of echo signal intensity.The condition number value and standard deviation of fractional anisotropy for each scheme can be used to evaluate image quality.Results demonstrated that increasing gradient direction to some extent resulted in improved effects.Therefore,the traditional 6 and 15 directions should not be considered optimal scan protocols for clinical DTI application.In a scheme with 20 directions,the condition number and standard deviation of fractional anisotropy of the encoding gradients matrix were significantly reduced,and resulted in more clearly and accurately displayed neural tissue.Results demonstrated that the scheme with 20diffusion gradient directions provided better accuracy of structural renderings and could be an optimal scan protocol for clinical DTI application.

  15. Diffusion-Weighted Magnetic Resonance Imaging in Rhombencephalitis due to Listeria monocytogenes

    Energy Technology Data Exchange (ETDEWEB)

    Hatipoglu, H.G.; Onbasioglu Gurbuz, M.; Sakman, B.; Yuksel, E. [Dept. of Radiology, Ankara Numune Education and Research Hospital, Ankara (Turkey)

    2007-04-15

    We present diffusion-weighted imaging findings of a case of rhombencephalitis due to Listeria monocytogenes. It is a rare, life-threatening disorder. The diagnosis is difficult by clinical findings only. In this report, we aim to draw attention to the role of conventional and diffusion-weighted magnetic resonance imaging findings. To our knowledge, this is the first case report in the literature with apparent diffusion coefficient values of diseased brain parenchyma.

  16. Clinical applications for diffusion magnetic resonance imaging in radiotherapy.

    Science.gov (United States)

    Tsien, Christina; Cao, Yue; Chenevert, Thomas

    2014-07-01

    In this article, we review the clinical applications of diffusion magnetic resonance imaging (MRI) in the radiotherapy treatment of several key clinical sites, including those of the central nervous system, the head and neck, the prostate, and the cervix. Diffusion-weighted MRI (DWI) is an imaging technique that is rapidly gaining widespread acceptance owing to its ease and wide availability. DWI measures the mobility of water within tissue at the cellular level without the need of any exogenous contrast agent. For radiotherapy treatment planning, DWI improves upon conventional imaging techniques, by better characterization of tumor tissue properties required for tumor grading, diagnosis, and target volume delineation. Because DWI is also a sensitive marker for alterations in tumor cellularity, it has potential clinical applications in the early assessment of treatment response following radiation therapy.

  17. Atypical pyogenic brain abscess evaluation by diffusion-weighted imaging: diagnosis with multimodality MR imaging.

    Science.gov (United States)

    Ozbayrak, Mustafa; Ulus, Ozden Sila; Berkman, Mehmet Zafer; Kocagoz, Sesin; Karaarslan, Ercan

    2015-10-01

    Whether a brain abscess is apparent by imaging depends on the stage of the abscess at the time of imaging, as well as the etiology of the infection. Because conventional magnetic resonance imaging (MRI) is limited in its ability to distinguish brain abscesses from necrotic tumors, advanced techniques are required. The management of these two disease entities differs and can potentially affect the clinical outcome. We report a case having atypical imaging features of a pyogenic brain abscess on advanced MRI, in particular, on diffusion-weighted and perfusion imaging, in a patient with osteosarcoma undergoing chemotherapy.

  18. Time-dependent Diffusion Coefficient and Conventional Diffusion Constant of Nanoparticles in Polymer Melts by Mode-coupling Theory

    Institute of Scientific and Technical Information of China (English)

    Xin-yu Lai; Nan-rong Zhao

    2013-01-01

    Time-dependent diffusion coefficient and conventional diffusion constant are calculated and analyzed to study diffusion of nanoparticles in polymer melts.A generalized Langevin equation is adopted to describe the diffusion dynamics.Mode-coupling theory is employed to calculate the memory kernel of friction.For simplicity,only microscopic terms arising from binary collision and coupling to the solvent density fluctuation are included in the formalism.The equilibrium structural information functions of the polymer nanocomposites required by mode-coupling theory are calculated on the basis of polymer reference interaction site model with Percus-Yevick closure.The effect of nanoparticle size and that of the polymer size are clarified explicitly.The structural functions,the friction kernel,as well as the diffusion coefficient show a rich variety with varying nanoparticle radius and polymer chain length.We find that for small nanoparticles or short chain polymers,the characteristic short time non-Markov diffusion dynamics becomes more prominent,and the diffusion coefficient takes longer time to approach asymptotically the conventional diffusion constant.This constant due to the microscopic contributions will decrease with the increase of nanoparticle size,while increase with polymer size.Furthermore,our result of diffusion constant from modecoupling theory is compared with the value predicted from the Stokes-Einstein relation.It shows that the microscopic contributions to the diffusion constant are dominant for small nanoparticles or long chain polymers.Inversely,when nanonparticle is big,or polymer chain is short,the hydrodynamic contribution might play a significant role.

  19. Spatial Mapping of Translational Diffusion Coefficients Using Diffusion Tensor Imaging: A Mathematical Description

    OpenAIRE

    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 diffu...

  20. Utility of diffusion tensor imaging parameters for diagnosis of hemimegalencephaly.

    Science.gov (United States)

    Oikawa, Tomomi; Tatewaki, Yasuko; Murata, Takaki; Kato, Yumiko; Mugikura, Shunji; Takase, Kei; Takahashi, Shoki

    2015-12-01

    Hemimegalencephaly is a rare hamartomatous entity characterised by enlargement of all or part of the cerebral hemisphere ipsilaterally with cortical dysgenesis, large lateral ventricle and white matter hypertrophy with or without advanced myelination. Although conventional magnetic resonance imaging (MRI) is useful for detecting these diagnostic features, hemimegalencephaly is not always easily distinguished from other entities, especially when hemimegalencephaly shows blurring between the grey and white matter. Diffusion tensor imaging (DTI) is a functional MRI technique commonly used to assess the integrity of white matter. The usefulness of DTI in assessing hemimegalencephaly has not been fully elucidated. In this study, we clarified the characteristics of hemimegalencephaly with regard to DTI and its parameters including fractional anisotropy and apparent diffusion coefficient. Three patients with hemimegalencephaly underwent MRI including DTI. We first visually compared fractional anisotropy mapping and conventional MRI. Next, we quantitatively measured the fractional anisotropy and apparent diffusion coefficient values in the subcortical white matter of the hemisphere with hemimegalencephaly and corresponding normal-appearing contralateral regions and analysed the values using the Mann-Whitney U test. On fractional anisotropy mapping, we could clearly distinguish the junction of grey and white matter and observed thicker white matter in the hemisphere with hemimegalencephaly, which was unclear on conventional MRI. The white matter in the hemisphere with hemimegalencephaly showed significantly higher fractional anisotropy (Phemimegalencephaly features and could be useful in its assessment. © The Author(s) 2015.

  1. Diffusion imaging in pediatric central nervous system infections

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, J. [Dept. de Imagiologia, Hospital Geral De Santo Antonio, Porto (Portugal); Zimmerman, R.A.; Haselgrove, J.C.; Bilaniuk, L.T.; Hunter, J.V. [Dept. of Radiology, Children' s Hospital of Philadelphia, PA (United States)

    2001-12-01

    Our purpose was to investigate the role of diffusion imaging (DI) in central nervous system (CNS) infections in pediatric patients. It was anticipated that DI would be more sensitive than conventional MRI in the detection of the infarctive complications of infection, and possibly, in the detection of the infectious process as well. Seventeen pediatric patients, eight having meningitis'' five with herpes encephalitis, three with brain abscess or cerebritis and one with sepsis, were evaluated at 1.5-T with DI. All herpes patients had positive DI at the site of herpetic involvement, and two had the addition of watershed infarctions. DI demonstrated more lesions in three of the four cases of herpetic encephalitis. Half the meningitis cases had watershed infarction where DI was better and half had vasculitic infarctions in which DI was equal to or better than conventional MRI. Diffusion imaging was more sensitive than conventional MRI alone in detection of changes due to infections and ischemic lesions, but did not differentiate between them by DI or apparent diffusion coefficient (ADC), although anatomic distribution of lesions proved useful. (orig.)

  2. Diffusion-weighted MR imaging (DWI) in spinal cord ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Thurnher, Majda M. [Medical University of Vienna, Department of Radiology, Neuroradiology Section, Vienna (Austria); Bammer, Roland [Stanford University, Lucas MRS/I Center, Department of Radiology, Stanford, CA (United States)

    2006-11-15

    Spinal cord infarction is a rare clinical diagnosis characterized by a sudden onset of paralysis, bowel and bladder dysfunction, and loss of pain and temperature perception, with preservation of proprioception and vibration sense. Magnetic resonance imaging (MRI) usually demonstrates intramedullary hyperintensity on T2-weighted MR images with cord enlargement. However, in approximately 45% of patients, MR shows no abnormality. Diffusion-weighted MR imaging (DWI) has been widely used for the evaluation of a variety of brain disorders, especially for acute stroke. Preliminary data suggest that DWI has the potential to be useful in the early detection of spinal infarction. We performed DWI, using navigated, interleaved, multishot echo planar imaging (IEPI), in a series of six patients with a clinical suspicion of acute spinal cord ischemia. In all patients, high signal was observed on isotropic DWI images with low ADC values (0.23 and 0.86 x 10{sup -3} cm{sup 2}/s), indicative of restricted diffusion. We analyzed the imaging findings from conventional MR sequences and diffusion-weighted MR sequences in six patients with spinal cord infarction, compared the findings with those in published series, and discuss the value of DWI in spinal cord ischemia based on current experience. Although the number of patients with described DWI findings totals only 23, the results of previously published studies and those of our study suggest that DWI has the potential to be a useful and feasible technique for the detection of spinal infarction. (orig.)

  3. Meduloblastoma: correlação entre ressonância magnética convencional, difusão e espectroscopia de prótons Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

    Directory of Open Access Journals (Sweden)

    Mariana Vieira de Melo da Fonte

    2008-12-01

    Full Text Available OBJETIVO: Correlacionar os achados de ressonância magnética convencional, difusão e espectroscopia de prótons nos meduloblastomas, e compará-los aos dados da literatura. MATERIAIS E MÉTODOS: Análise retrospectiva de exames de ressonância magnética pré-operatórios de nove pacientes na faixa pediátrica com diagnóstico histológico de meduloblastoma (oito desmoplásicos e um de células gigantes. Foram considerados dados demográficos e características do tumor como localização, característica morfológica, intensidade de sinal, realce, disseminação e achados na difusão e espectroscopia. RESULTADOS: Na maioria dos casos os tumores apresentaram epicentro no vermis cerebelar (77,8%, sendo predominantemente sólido (88,9%, com hipossinal nas seqüências ponderadas em T1 e iso/hipersinal nas seqüências ponderadas em T2 e FLAIR, realce heterogêneo (100%, sinais de disseminação/extensão tumoral (77,8% e restrição à movimentação das moléculas de água (100%. A espectroscopia de prótons pela técnica STEAM (n = 6 demonstrou redução da relação Naa/Cr (83,3% e aumento de Co/Cr (100% e mI/Cr (66,7%, e pela técnica PRESS (n = 7 evidenciou pico de lactato (57,1%. CONCLUSÃO: O conjunto dos achados macroscópicos obtidos pela ressonância magnética, somado às características bioquímicas dos meduloblastomas, têm sido úteis na tentativa de diferenciação entre os principais tumores da fossa posterior.OBJECTIVE: To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. MATERIALS AND METHODS: Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma were retrospectively reviewed, considering demographics as well as tumors characteristics

  4. Diffusion tensor imaging of peripheral nerves.

    Science.gov (United States)

    Jambawalikar, Sachin; Baum, Jeremy; Button, Terry; Li, Haifang; Geronimo, Veronica; Gould, Elaine S

    2010-11-01

    Magnetic resonance diffusion tensor imaging (DTI) allows the directional dependence of water diffusion to be studied. Analysis of the resulting image data allows for the determination of fractional anisotropy (FA), apparent diffusion coefficient (ADC), as well as allowing three-dimensional visualization of the fiber tract (tractography). We visualized the ulnar nerve of ten healthy volunteers with DTI. We found FA to be 0.752 ± 0.067 and the ADC to be 0.96 ± 0.13 × 10(-3) mm(2)/s. A nuts-and-bolts description of the physical aspects of DTI is provided as an educational process for readers.

  5. Diffusion weighted magnetic resonance imaging in

    Directory of Open Access Journals (Sweden)

    A.H. Afifi

    2016-03-01

    Conclusions: MRI DWI offers quick and non-invasive technique to distinct between viable and necrotic tumor areas and helps the diagnosis of residual tumor. Potential effect of treatment can be detected as increase in the diffusion coefficient. We recommend that optimal follow-up after image guided trans-catheter tumor therapy should include DWI and contrast-enhanced MRI.

  6. Diffusion weighted imaging with circularly polarized oscillating gradients

    DEFF Research Database (Denmark)

    Lundell, Henrik; Sønderby, Casper Kaae; Dyrby, Tim B

    2015-01-01

    in diffusion weighting with encoding in a plane rather than in one direction. CP-OGSE can be used for rotationally invariant acquisitions on anisotropic tissues. METHODS: Experiments with a 4.7 T preclinical scanner on a postmortem monkey brain as well as simulations were performed using conventional OGSE...... and CP-OGSE. RESULTS: Simulations and experiments show that CP-OGSE provides the same microstructural information as OGSE but provides more robust parameter estimates with limited gradient strength. CONCLUSIONS: CP-OGSE can be an important contribution for making OGSE imaging more effective in clinical...... imaging settings with limited gradient strength. Furthermore, the improved diffusion weighting can also be used to expand the investigated frequency range. Magn Reson Med, 2014. © 2014 Wiley Periodicals, Inc....

  7. Converting Multi-Shell and Diffusion Spectrum Imaging to High Angular Resolution Diffusion Imaging.

    Science.gov (United States)

    Yeh, Fang-Cheng; Verstynen, Timothy D

    2016-01-01

    Multi-shell and diffusion spectrum imaging (DSI) are becoming increasingly popular methods of acquiring diffusion MRI data in a research context. However, single-shell acquisitions, such as diffusion tensor imaging (DTI) and high angular resolution diffusion imaging (HARDI), still remain the most common acquisition schemes in practice. Here we tested whether multi-shell and DSI data have conversion flexibility to be interpolated into corresponding HARDI data. We acquired multi-shell and DSI data on both a phantom and in vivo human tissue and converted them to HARDI. The correlation and difference between their diffusion signals, anisotropy values, diffusivity measurements, fiber orientations, connectivity matrices, and network measures were examined. Our analysis result showed that the diffusion signals, anisotropy, diffusivity, and connectivity matrix of the HARDI converted from multi-shell and DSI were highly correlated with those of the HARDI acquired on the MR scanner, with correlation coefficients around 0.8~0.9. The average angular error between converted and original HARDI was 20.7° at voxels with signal-to-noise ratios greater than 5. The network topology measures had less than 2% difference, whereas the average nodal measures had a percentage difference around 4~7%. In general, multi-shell and DSI acquisitions can be converted to their corresponding single-shell HARDI with high fidelity. This supports multi-shell and DSI acquisitions over HARDI acquisition as the scheme of choice for diffusion acquisitions.

  8. Converting Multi-Shell and Diffusion Spectrum Imaging to High Angular Resolution Diffusion Imaging

    Science.gov (United States)

    Yeh, Fang-Cheng; Verstynen, Timothy D.

    2016-01-01

    Multi-shell and diffusion spectrum imaging (DSI) are becoming increasingly popular methods of acquiring diffusion MRI data in a research context. However, single-shell acquisitions, such as diffusion tensor imaging (DTI) and high angular resolution diffusion imaging (HARDI), still remain the most common acquisition schemes in practice. Here we tested whether multi-shell and DSI data have conversion flexibility to be interpolated into corresponding HARDI data. We acquired multi-shell and DSI data on both a phantom and in vivo human tissue and converted them to HARDI. The correlation and difference between their diffusion signals, anisotropy values, diffusivity measurements, fiber orientations, connectivity matrices, and network measures were examined. Our analysis result showed that the diffusion signals, anisotropy, diffusivity, and connectivity matrix of the HARDI converted from multi-shell and DSI were highly correlated with those of the HARDI acquired on the MR scanner, with correlation coefficients around 0.8~0.9. The average angular error between converted and original HARDI was 20.7° at voxels with signal-to-noise ratios greater than 5. The network topology measures had less than 2% difference, whereas the average nodal measures had a percentage difference around 4~7%. In general, multi-shell and DSI acquisitions can be converted to their corresponding single-shell HARDI with high fidelity. This supports multi-shell and DSI acquisitions over HARDI acquisition as the scheme of choice for diffusion acquisitions. PMID:27683539

  9. The usefulness of diffusion tensor imaging in detection of diffuse axonal injury in a patient with head trauma

    Institute of Scientific and Technical Information of China (English)

    Hyeok Gyu Kwon; Sung Ho Jang

    2012-01-01

    Diffuse axonal injury is the predominant mechanism of injuries in patients with traumatic brain injury. Neither conventional brain computed tomography nor magnetic resonance imaging has shown sufficient sensitivity in the diagnosis of diffuse axonal injury. In the current study, we attempted to demonstrate the usefulness of diffusion tensor imaging in the detection of lesion sites of diffuse axonal injury in a patient with head trauma who had been misdiagnosed as having a stroke. A 44-year-old man fell from a height of about 2 m. Brain magnetic resonance imaging (32 months after onset) showed leukomalactic lesions in the isthmus of the corpus callosum and the left temporal lobe. He presented with mild quadriparesis, intentional tremor of both hands, and trunkal ataxia. From diffusion tensor imaging results of 33 months after traumatic brain injury onset, we found diffuse axonal injury in the right corticospinal tract (centrum semiovale, pons), both fornices (columns and crus), and both inferior cerebellar peduncles (cerebellar portions). We think that diffusion tensor imaging could be a useful tool in the detection of lesion sites of diffuse axonal injuryin patients with head trauma.

  10. Color Histogram Diffusion for Image Enhancement

    Science.gov (United States)

    Kim, Taemin

    2011-01-01

    Various color histogram equalization (CHE) methods have been proposed to extend grayscale histogram equalization (GHE) for color images. In this paper a new method called histogram diffusion that extends the GHE method to arbitrary dimensions is proposed. Ranges in a histogram are specified as overlapping bars of uniform heights and variable widths which are proportional to their frequencies. This diagram is called the vistogram. As an alternative approach to GHE, the squared error of the vistogram from the uniform distribution is minimized. Each bar in the vistogram is approximated by a Gaussian function. Gaussian particles in the vistoram diffuse as a nonlinear autonomous system of ordinary differential equations. CHE results of color images showed that the approach is effective.

  11. 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.)

  12. Diffusion tensor imaging and fiber tractography in brain malformations.

    Science.gov (United States)

    Poretti, Andrea; Meoded, Avner; Rossi, Andrea; Raybaud, Charles; Huisman, Thierry A G M

    2013-01-01

    Diffusion tensor imaging (DTI) is an advanced MR technique that provides qualitative and quantitative information about the micro-architecture of white matter. DTI and its post-processing tool fiber tractography (FT) have been increasingly used in the last decade to investigate the microstructural neuroarchitecture of brain malformations. This article aims to review the use of DTI and FT in the evaluation of a variety of common, well-described brain malformations, in particular by pointing out the additional information that DTI and FT renders compared with conventional MR sequences. In addition, the relevant existing literature is summarized.

  13. Diffusion tensor imaging and fiber tractography in brain malformations

    Energy Technology Data Exchange (ETDEWEB)

    Poretti, Andrea; Meoded, Avner; Huisman, Thierry A.G.M. [The Johns Hopkins University School of Medicine, Division of Pediatric Radiology, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Rossi, Andrea [G. Gaslini Institue, Pediatric Neuroradiology, Genova (Italy); Raybaud, Charles [University of Toronto, Department of Neuroradiology, Hospital for Sick Children, Toronto, ON (Canada)

    2013-01-15

    Diffusion tensor imaging (DTI) is an advanced MR technique that provides qualitative and quantitative information about the micro-architecture of white matter. DTI and its post-processing tool fiber tractography (FT) have been increasingly used in the last decade to investigate the microstructural neuroarchitecture of brain malformations. This article aims to review the use of DTI and FT in the evaluation of a variety of common, well-described brain malformations, in particular by pointing out the additional information that DTI and FT renders compared with conventional MR sequences. In addition, the relevant existing literature is summarized. (orig.)

  14. Fetal diffusion imaging: pearls and solutions.

    Science.gov (United States)

    Kasprian, Gregor; Del Río, Maria; Prayer, Daniela

    2010-12-01

    Recently, diffusion-weighted (DWI) magnetic resonance imaging of the fetus has evolved from a basic research application to an important diagnostic imaging tool in fetal magnetic resonance imaging. Although technically challenging and still plagued with several sources of artifacts, DWI can add clinically important information, which cannot be provided by any other prenatal imaging modality. Its potential to noninvasively probe tissue structures on the basis of Brownian molecular motion enables the detection of early changes associated with acute fetal diseases, as well as structural alterations of functionally diverse compartments of different fetal organs. In this article, the current clinical applications of fetal brain and body DWI are outlined, as well as its current limitations.

  15. The comparative effectiveness of conventional and digital image libraries.

    Science.gov (United States)

    McColl, R I; Johnson, A

    2001-03-01

    Before introducing a hospital-wide image database to improve access, navigation and retrieval speed, a comparative study between a conventional slide library and a matching image database was undertaken to assess its relative benefits. Paired time trials and personal questionnaires revealed faster retrieval rates, higher image quality, and easier viewing for the pilot digital image database. Analysis of confidentiality, copyright and data protection exposed similar issues for both systems, thus concluding that the digital image database is a more effective library system. The authors suggest that in the future, medical images will be stored on large, professionally administered, centrally located file servers, allowing specialist image libraries to be tailored locally for individual users. The further integration of the database with web technology will enable cheap and efficient remote access for a wide range of users.

  16. Diffusion-weighted imaging: basic concepts and application in cerebral stroke and head trauma

    Energy Technology Data Exchange (ETDEWEB)

    Huisman, Thierry A.G.M. [Department of Radiology, Neuroradiology Section and MGH-NMR Center, Massachusetts General Hospital and Harvard Medical School, MA 02129, Boston (United States); Department of Radiology, University Children' s Hospital Zurich, Steinwiesstrasse 75, 8032, Zurich (Switzerland)

    2003-10-01

    Diffusion-weighted imaging (DWI) of the brain represents a new imaging technique that extends imaging from depiction of neuroanatomy to the level of function and physiology. DWI measures a fundamentally different physiological parameter compared with conventional MRI. Image contrast is related to differences in the diffusion rate of water molecules rather than to changes in total tissue water. DWI can reveal pathology in cases where conventional MRI remains unremarkable. DWI has proven to be highly sensitive in the early detection of acute cerebral ischemia and seems promising in the evaluation of traumatic brain injury. DWI can differentiate between lesions with decreased and increased diffusion. In addition, full-tensor DWI can evaluate the microscopic architecture of the brain, in particular white matter tracts, by measuring the degree and spatial distribution of anisotropic diffusion within the brain. This article reviews the basic concepts of DWI and its application in cerebral ischemia and traumatic brain injury. (orig.)

  17. Diffusion-Weighted Images Superresolution Using High-Order SVD.

    Science.gov (United States)

    Wu, Xi; Yang, Zhipeng; Hu, Jinrong; Peng, Jing; He, Peiyu; Zhou, Jiliu

    2016-01-01

    The spatial resolution of diffusion-weighted imaging (DWI) is limited by several physical and clinical considerations, such as practical scanning times. Interpolation methods, which are widely used to enhance resolution, often result in blurred edges. Advanced superresolution scanning acquires images with specific protocols and long acquisition times. In this paper, we propose a novel single image superresolution (SR) method which introduces high-order SVD (HOSVD) to regularize the patch-based SR framework on DWI datasets. The proposed method was implemented on an adaptive basis which ensured a more accurate reconstruction of high-resolution DWI datasets. Meanwhile, the intrinsic dimensional decreasing property of HOSVD is also beneficial for reducing the computational burden. Experimental results from both synthetic and real DWI datasets demonstrate that the proposed method enhances the details in reconstructed high-resolution DWI datasets and outperforms conventional techniques such as interpolation methods and nonlocal upsampling.

  18. Conventional and advanced MR imaging in infantile Refsum disease.

    Science.gov (United States)

    Kılıç, Mustafa; Karlı-Oğuz, Kader; Haliloğlu, Göknur; Topçu, Meral; Wanders, Ronald James; Coşkun, Turgay

    2015-01-01

    We report magnetic resonance (MR) imaging findings including diffusion-weighted imaging and proton MR spectroscopy findings in a patient with infantile Refsum disease. The initial diagnosis was made on the basis of history, clinical findings and biochemical studies. Bilateral and symmetrical involvement of the peritrigonal white matter, centrum semiovale, thalami, corpus callosum and corticospinal tracts as assessed by increased T2 signal was highly suggestive of a peroxisomal disorder. Facilitated diffusion was observed in diseased parenchyma. Long echo-time (TE: 270 ms) MRS showed decreased N-acetyl-aspartate/creatine and elevated choline/creatine and lactate; short echo-time MRS (TE: 30 ms) revealed increased myoinositol at 3.56 ppm and lipid peaks at 0.9 and 1.3 ppm. A major contribution to the differential diagnosis came from MR imaging and proton MRS, as discussed in this report.

  19. Diffusion kurtosis imaging of the liver at 3 Tesla: in vivo comparison to standard diffusion-weighted imaging.

    Science.gov (United States)

    Budjan, Johannes; Sauter, Elke A; Zoellner, Frank G; Lemke, Andreas; Wambsganss, Jens; Schoenberg, Stefan O; Attenberger, Ulrike I

    2017-01-01

    Background Functional techniques like diffusion-weighted imaging (DWI) are gaining more and more importance in liver magnetic resonance imaging (MRI). Diffusion kurtosis imaging (DKI) is an advanced technique that might help to overcome current limitations of DWI. Purpose To evaluate DKI for the differentiation of hepatic lesions in comparison to conventional DWI at 3 Tesla. Material and Methods Fifty-six consecutive patients were examined using a routine abdominal MR protocol at 3 Tesla which included DWI with b-values of 50, 400, 800, and 1000 s/mm(2). Apparent diffusion coefficient maps were calculated applying a standard mono-exponential fit, while a non-Gaussian kurtosis fit was used to obtain DKI maps. ADC as well as Kurtosis-corrected diffusion ( D) values were quantified by region of interest analysis and compared between lesions. Results Sixty-eight hepatic lesions (hepatocellular carcinoma [HCC] [n = 25]; hepatic adenoma [n = 4], cysts [n = 18]; hepatic hemangioma [HH] [n = 18]; and focal nodular hyperplasia [n = 3]) were identified. Differentiation of malignant and benign lesions was possible based on both DWI ADC as well as DKI D-values ( P values were in the range of 0.04 to < 0.0001). Conclusion In vivo abdominal DKI calculated using standard b-values is feasible and enables quantitative differentiation between malignant and benign liver lesions. Assessment of conventional ADC values leads to similar results when using b-values below 1000 s/mm(2) for DKI calculation.

  20. Clinical benefits of diffusion tensor imaging in hydrocephalus.

    Science.gov (United States)

    Ben-Sira, Liat; Goder, Noam; Bassan, Haim; Lifshits, Shlomi; Assaf, Yaniv; Constantini, Shlomi

    2015-08-01

    OBJECT The object of this study was to use diffusion tensor imaging (DTI) to evaluate and characterize white matter changes in hydrocephalus. METHODS The authors performed a retrospective analysis of DTI in a cohort of patients with hydrocephalus (n = 35), 19 of whom had both pre- and postsurgical imaging studies. These patient's DTI values were compared with values extracted from age-dependent trend lines computed from a healthy subject group (n = 70, age span 14 months-14 years). Several DTI parameters in different regions of interest (ROIs) were evaluated to find the most sensitive parameters for clinical decision making in hydrocephalus. RESULTS Compared with healthy controls, patients with active hydrocephalus had a statistically significant change in all DTI parameters. The most sensitive and specific DTI parameter for predicting hydrocephalus was axial diffusivity (λ1) measured at the level of the corona radiata. Diffusion tensor imaging parameters correlated with several conventional radiological parameters in the assessment of hydrocephalus but were not superior to them. There was no convincing correlation between clinical disease severity and DTI parameters. When examining the pre- and postsurgical effect, it was found that DTI may be a sensitive tool for estimating tissue improvement. CONCLUSIONS This large-cohort study with a multidisciplinary approach combining clinical, neurological, radiological, and multiple DTI parameters revealed the most sensitive DTI parameters for identifying hydrocephalus and suggested that they may serve as an important tool for the disorder's quantitative radiological assessment.

  1. Appearances of diffuse excessive high signal intensity (DEHSI) on MR imaging following preterm birth

    Energy Technology Data Exchange (ETDEWEB)

    Hart, Anthony R. [Sheffield Teaching Hospital NHS Foundation Trust, Department of Neonatology, Jessop Wing, Sheffield (United Kingdom); University of Sheffield, Academic Unit of Radiology, Royal Hallamshire Hospital, Sheffield (United Kingdom); University of Sheffield, Department of Academic Radiology, Royal Hallamshire Hospital, Sheffield (United Kingdom); Smith, Michael F. [Sheffield Teaching Hospital NHS Foundation Trust, Department of Neonatology, Jessop Wing, Sheffield (United Kingdom); Rigby, Alan S. [University of Hull, Postgraduate Medical Centre, Castle Hill Hospital, East Yorkshire (United Kingdom); Wallis, Lauren I.; Whitby, Elspeth H. [University of Sheffield, Academic Unit of Radiology, Royal Hallamshire Hospital, Sheffield (United Kingdom)

    2010-08-15

    Diffuse damage to the periventricular white matter has recently been suggested to be a cause of the cognitive deficits seen following preterm birth. It is unclear whether this form of injury can be visualised on MR imaging, but one group has described diffuse excessive high signal intensity (DEHSI) as a possible form of diffuse white matter injury. This finding is dependant on window imaging and the subjective assessment of the reviewer, but little data have been published on the degree of subjectivity on its appearance among raters. To assess the subjectivity of DEHSI on conventional and ultrafast T2-weighted MR imaging following preterm birth. An observational study of 40 preterm infants who had MR imaging of the brain around term-equivalent age, including conventional fast spin-echo (FSE) and ultrafast single-shot fast spin-echo (SSFSE) T2-weighted sequences in the axial plane. Images were anonymised and scored twice by four observers for the presence of DEHSI. Inter- and intra-observer agreement were calculated. Sixty-five percent of conventional and 100% of the ultrafast images were of diagnostic quality. DEHSI was noted in between 0% and 69.2% of conventional images and 27.5-90% of the ultrafast images. Inter- and intra-observer agreement ranged from none to moderate. The visual appearances of DEHSI on conventional FSE and ultrafast SSFSE T2-W images are highly subjective, limiting its clinical application. (orig.)

  2. Diffusion and perfusion imaging of bone marrow

    Energy Technology Data Exchange (ETDEWEB)

    Biffar, Andreas; Dietrich, Olaf [Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, LMU University Hospitals, Grosshadern-Munich (Germany); Sourbron, Steven [Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, LMU University Hospitals, Grosshadern-Munich (Germany); Division of Medical Physics, University of Leeds, Leeds (United Kingdom); Duerr, Hans-Roland [Department of Orthopedic Surgery, LMU University Hospitals, Grosshadern-Munich (Germany); Reiser, Maximilian F. [Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, LMU University Hospitals, Grosshadern-Munich (Germany); Department of Clinical Radiology, LMU University Hospitals, Grosshadern-Munich (Germany); Baur-Melnyk, Andrea, E-mail: andrea.baur@med.uni-muenchen.de [Department of Clinical Radiology, LMU University Hospitals, Grosshadern-Munich (Germany)

    2010-12-15

    In diffusion-weighted magnetic resonance imaging (DWI), the observed MRI signal intensity is attenuated by the self-diffusion of water molecules. DWI provides information about the microscopic structure and organization of a biological tissue, since the extent and orientation of molecular motion is influenced by these tissue properties. The most common method to measure perfusion in the body using MRI is T1-weighted dynamic contrast enhancement (DCE-MRI). The analysis of DCE-MRI data allows determining the perfusion and permeability of a biological tissue. DWI as well as DCE-MRI are established techniques in MRI of the brain, while significantly fewer studies have been published in body imaging. In recent years, both techniques have been applied successfully in healthy bone marrow as well as for the characterization of bone marrow alterations or lesions; e.g., DWI has been used in particular for the differentiation of benign and malignant vertebral compression fractures. In this review article, firstly a short introduction to diffusion-weighted and dynamic contrast-enhanced MRI is given. Non-quantitative and quantitative approaches for the analysis of DWI and semiquantitative and quantitative approaches for the analysis of DCE-MRI are introduced. Afterwards a detailed overview of the results of both techniques in healthy bone marrow and their applications for the diagnosis of various bone-marrow pathologies, like osteoporosis, bone tumors, and vertebral compression fractures are described.

  3. On some applications of diffusion processes for image processing

    Energy Technology Data Exchange (ETDEWEB)

    Morfu, S., E-mail: smorfu@u-bourgogne.f [Laboratoire d' Electronique, Informatique et Image (LE2i), UMR Cnrs 5158, Aile des Sciences de l' Ingenieur, BP 47870, 21078 Dijon Cedex (France)

    2009-06-29

    We propose a new algorithm inspired by the properties of diffusion processes for image filtering. We show that purely nonlinear diffusion processes ruled by Fisher equation allows contrast enhancement and noise filtering, but involves a blurry image. By contrast, anisotropic diffusion, described by Perona and Malik algorithm, allows noise filtering and preserves the edges. We show that combining the properties of anisotropic diffusion with those of nonlinear diffusion provides a better processing tool which enables noise filtering, contrast enhancement and edge preserving.

  4. Detecting Diffuse Sources in Astronomical Images

    CERN Document Server

    Butler-Yeoman, T; Hollitt, C P; Hogg, D W; Johnston-Hollitt, M

    2016-01-01

    We present an algorithm capable of detecting diffuse, dim sources of any size in an astronomical image. These sources often defeat traditional methods for source finding, which expand regions around points of high intensity. Extended sources often have no bright points and are only detectable when viewed as a whole, so a more sophisticated approach is required. Our algorithm operates at all scales simultaneously by considering a tree of nested candidate bounding boxes, and inverts a hierarchical Bayesian generative model to obtain the probability of sources existing at given locations and sizes. This model naturally accommodates the detection of nested sources, and no prior knowledge of the distribution of a source, or even the background, is required. The algorithm scales nearly linear with the number of pixels making it feasible to run on large images, and requires minimal parameter tweaking to be effective. We demonstrate the algorithm on several types of astronomical and artificial images.

  5. Discriminating Yogurt Microstructure Using Diffuse Reflectance Images

    DEFF Research Database (Denmark)

    Skytte, Jacob Lercke; Møller, Flemming; Abildgaard, Otto Højager Attermann;

    2015-01-01

    modalities is evaluated on a 24 factorial design covering four common production parameters, which significantly change the chemistry and the microstructure of the yogurt. It is found that the DRIs can be as discriminative as the CSLM images in certain cases, however the performance is highly governed...... microstructures using hyperspectral (500-900nm) diffuse reflectance images (DRIs) – a technique potentially well suited for inline process control. Comparisons are made to quantified measures of the yogurt microstructure observed through confocal scanning laser microscopy (CSLM). The output signal from both...... by the chemistry of the sample. Also, the DRIs shows better correlation to the CSLM images and are more discriminative when considering shorter wavelengths....

  6. 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.

  7. 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

    2016-01-01

    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. PMID:27441031

  8. Diffusion-weighted imaging in patients with progressive multifocal leukoencephalopathy

    Energy Technology Data Exchange (ETDEWEB)

    Cosottini, M. [University of Pisa, Department of Neuroscience, Pisa (Italy); Service of Neuroradiology AO, Pisa (Italy); Tavarelli, C.; De Cori, S.; Bartolozzi, C. [University of Pisa, Department of Radiology, Pisa (Italy); Del Bono, L.; Doria, G. [Unit of Infectious Diseases AO, Pisa (Italy); Giannelli, M. [Unit of Medical Physics, Pisa (Italy); Michelassi, M.C. [Service of Neuroradiology AO, Pisa (Italy); Murri, L. [University of Pisa, Department of Neuroscience, Pisa (Italy)

    2008-05-15

    Progressive multifocal leukoencephalopathy (PML) is a severe demyelinating disease of the central nervous system due to JC polyoma virus infection of oligodendrocytes. PML develops in patients with impaired T-cell function as occurs in HIV, malignancy or immunosuppressive drugs users. Until now no imaging methods have been reported to correlate with clinical status. Diffusion-weighted imaging (DWI) is a robust MRI tool in investigating white matter architecture and diseases. The aim of our work was to assess diffusion abnormalities in focal white matter lesions in patients with PML and to correlate the lesion load measured with conventional MRI and DWI to clinical variables. We evaluated eight patients with a biopsy or laboratory-supported diagnosis of PML. All patients underwent MRI including conventional sequences (fluid attenuated inversion recovery-FLAIR) and DWI. Mean diffusivity (MD) maps were used to quantify diffusion on white matter lesions. Global lesion load was calculated by manually tracing lesions on FLAIR images, while total, central core and peripheral lesion loads were calculated by manually tracing lesions on DWI images. Lesion load obtained with the conventional or DWI-based methods were correlated with clinical variables such as disease duration, disease severity and survival. White matter focal lesions are characterized by a central core with low signal on DWI images and high MD (1.853 x 10{sup -3} mm2/s), surrounded by a rim of high signal intensity on DWI and lower MD (1.1 x 10{sup -3} mm2/s). The MD value of normal-appearing white matter is higher although not statistically significant (0.783 x 10{sup -3} mm2/s) with respect to control subjects (0.750 x 10{sup -3} mm2/s). Inter-rater correlations of global lesion load between FLAIR (3.96%) and DWI (3.43%) was excellent (ICC =0.87). Global lesion load on FLAIR and DWI correlates with disease duration and severity (respectively, p = 0.037, p = 0.0272 with Karnofsky scale and p = 0.0338 with

  9. Diffusion-relaxation correlation spectroscopic imaging: A multidimensional approach for probing microstructure.

    Science.gov (United States)

    Kim, Daeun; Doyle, Eamon K; Wisnowski, Jessica L; Kim, Joong Hee; Haldar, Justin P

    2017-03-19

    To propose and evaluate a novel multidimensional approach for imaging subvoxel tissue compartments called Diffusion-Relaxation Correlation Spectroscopic Imaging. Multiexponential modeling of MR diffusion or relaxation data is commonly used to infer the many different microscopic tissue compartments that contribute signal to macroscopic MR imaging voxels. However, multiexponential estimation is known to be difficult and ill-posed. Observing that this ill-posedness is theoretically reduced in higher dimensions, diffusion-relaxation correlation spectroscopic imaging uses a novel multidimensional imaging experiment that jointly encodes diffusion and relaxation information, and then uses a novel constrained reconstruction technique to generate a multidimensional diffusion-relaxation correlation spectrum for every voxel. The peaks of the multidimensional spectrum are expected to correspond to the distinct tissue microenvironments that are present within each macroscopic imaging voxel. Using numerical simulations, experiment data from a custom-built phantom, and experiment data from a mouse model of traumatic spinal cord injury, diffusion-relaxation correlation spectroscopic imaging is demonstrated to provide substantially better multicompartment resolving power compared to conventional diffusion- and relaxation-based methods. The diffusion-relaxation correlation spectroscopic imaging approach provides powerful new capabilities for resolving the different components of multicompartment tissue models, and can be leveraged to significantly expand the insights provided by MRI in studies of tissue microstructure. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  10. Diffuse Optical Tomography for Brain Imaging: Theory

    Science.gov (United States)

    Yuan, Zhen; Jiang, Huabei

    Diffuse optical tomography (DOT) is a noninvasive, nonionizing, and inexpensive imaging technique that uses near-infrared light to probe tissue optical properties. Regional variations in oxy- and deoxy-hemoglobin concentrations as well as blood flow and oxygen consumption can be imaged by monitoring spatiotemporal variations in the absorption spectra. For brain imaging, this provides DOT unique abilities to directly measure the hemodynamic, metabolic, and neuronal responses to cells (neurons), and tissue and organ activations with high temporal resolution and good tissue penetration. DOT can be used as a stand-alone modality or can be integrated with other imaging modalities such as fMRI/MRI, PET/CT, and EEG/MEG in studying neurophysiology and pathology. This book chapter serves as an introduction to the basic theory and principles of DOT for neuroimaging. It covers the major aspects of advances in neural optical imaging including mathematics, physics, chemistry, reconstruction algorithm, instrumentation, image-guided spectroscopy, neurovascular and neurometabolic coupling, and clinical applications.

  11. UV image processing to detect diffuse clouds

    Science.gov (United States)

    Armengot, M.; Gómez de Castro, A. I.; López-Santiago, J.; Sánchez-Doreste, N.

    2015-05-01

    The presence of diffuse clouds along the Galaxy is under consideration as far as they are related to stellar formation and their physical properties are not well understood. The signal received from most of these structures in the UV images is minimal compared to the point sources. The presence of noise in these images makes hard the analysis because the Signal-to-Noise ratio is proportionally much higher in these areas. However, the digital processing of the images shows that it is possible to enhance and target these clouds. Typically, this kind of treatment is done on purpose for specific research areas and the Astrophysicist's work depends on the computer tools and its possibilities for enhancing a particular area based on a prior knowledge. Automating this step is the goal of our work to make easier the study of these structures in UV images. In particular we have used the GALEX survey images in the aim of learning to automatically detect such clouds and be able of unsupervised detection and graphic enhancement to log them. Our experiments show the existence of some evidences in the UV images that allow the systematic computing and open the chance to generalize the algorithm to find these structures in universe areas where they have not been recorded yet.

  12. Diffusion weighted imaging in gynecological malignancies-present and future

    Institute of Scientific and Technical Information of China (English)

    Dinesh Manoharan; Chandan J Das; Ankita Aggarwal; Arun K Gupta

    2016-01-01

    The management of gynaecological malignancies has undergone a significant change in recent years with our improved understanding of cancer biogenetics, development of new treatment regimens and enhanced screening. Due to the rapid blooming of newer methods and techniques in gynaecology, surgery and oncology the scope and the role of imaging has also widened. Functional imaging in the form of diffusion weighted imaging(DWI) has been recently found to be very useful in assessing various tumours. Its ability to identify changes in the molecular level has dramatically changed the diagnostic approach of radiologists which was solely based on morphological criteria. It can improve the diagnostic accuracy of conventional magnetic resonance imaging, lend a hand in assessing tumour response to treatment regimens and detect tumour recurrence with better spatial resolution, negative radiation and diagnostic accuracy compared to positron emission tomography scan. The ability to quantify the diffusion has also lead to potential prediction of tumour aggressiveness and grade which directly correlate with the patient prognosis and management. Hence, it has become imperative for a radiologist to understand the concepts of DWI and its present and evolving role. In this article we present a brief description of the basics of DWI followed by its role in evaluation of female gynaecological malignancies.

  13. MR pyelography and conventional MR imaging in urinary tract obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Catalano, C.; Pavone, P.; Laghi, A.; Scipioni, A.; Panebianco, V.; Brillo, R.; Fraioli, F.; Passariello, R. [La Sapienza Univ., Rome (Italy). Department of Radiology-II

    1999-03-01

    Purpose: To evaluate the possible role of MR imaging in the assessment of patients with urinary tract obstruction by combining conventional MR imaging and MR pyelography (MRP). Material and methods: Forty-three patients with dilated upper urinary tract were studied with a high gradient strength 0.5 T magnet. Respiratory compensated T1-weighted, SE and T2-weighted TSE sequences were acquired in all patients. MRP images were obtained by using a respiratory compensated 3D T2-weighted TSE sequence. MRP images were reconstructed with a MIP algorithm. In all cases, urography and/or ascending pyelography were also performed. Images were independently evaluated by two radiologists. Results: The dilated tract ureter and the level of the obstruction could be correctly demonstrated in all cases. The cause of the obstruction was correctly demonstrated by examiner 1 in 90% and by examiner 2 in 88%. The interobserver agreement was high with a kappa-value of 0.96. Conclusion: In cases of obstructive hydroureteronephrosis MR imaging, combining MRP and conventional sequences, can be proposed as an accurate technique in the assessment of level and cause of obstruction. (orig.)

  14. Image Quality Stability of Whole-body Diffusion Weighted Imaging

    Institute of Scientific and Technical Information of China (English)

    Yun-bin Chen; Chun-miao Hu; Jing Zhong; Fei Sun

    2009-01-01

    To assess the reproducibility of whole-body diffusion weighted imaging (WB-DWI) technique in healthy volunteers under normal breathing with background body signal suppression. Methods WB-DWI was performed on 32 healthy volunteers twice within two-week period using short TI inversion-recovery diffusion-weighted echo-planar imaging sequence and built-in body coil. The volunteers were scanned across six stations continuously covering the entire body from the head to the feet under normal breathing. The bone apparent diffusion coefficient (ADC) and exponential ADC (eADC) of regions of interest (ROIs) were measured. We analyzed correlation of the results using paired-t-test to assess the reproducibility of the WB-DWl technique.Results We were successful in collecting and analyzing data of 64 WB-DWI images. There was no significant difference in bone ADC and eADC of 824 ROIs between the paired observers and paired scans (P>0.05). Most of the images from all stations were of diagnostic quality.Conclusion The measurements of bone ADC and eADC have good reproducibility. WB-DWI technique under normal breathing with background body signal suppression is adequate.

  15. Multi-compartment microscopic diffusion imaging.

    Science.gov (United States)

    Kaden, Enrico; Kelm, Nathaniel D; Carson, Robert P; Does, Mark D; Alexander, Daniel C

    2016-10-01

    This paper introduces a multi-compartment model for microscopic diffusion anisotropy imaging. The aim is to estimate microscopic features specific to the intra- and extra-neurite compartments in nervous tissue unconfounded by the effects of fibre crossings and orientation dispersion, which are ubiquitous in the brain. The proposed MRI method is based on the Spherical Mean Technique (SMT), which factors out the neurite orientation distribution and thus provides direct estimates of the microscopic tissue structure. This technique can be immediately used in the clinic for the assessment of various neurological conditions, as it requires only a widely available off-the-shelf sequence with two b-shells and high-angular gradient resolution achievable within clinically feasible scan times. To demonstrate the developed method, we use high-quality diffusion data acquired with a bespoke scanner system from the Human Connectome Project. This study establishes the normative values of the new biomarkers for a large cohort of healthy young adults, which may then support clinical diagnostics in patients. Moreover, we show that the microscopic diffusion indices offer direct sensitivity to pathological tissue alterations, exemplified in a preclinical animal model of Tuberous Sclerosis Complex (TSC), a genetic multi-organ disorder which impacts brain microstructure and hence may lead to neurological manifestations such as autism, epilepsy and developmental delay. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  16. Serial diffusion-weighted imaging in MELAS

    Energy Technology Data Exchange (ETDEWEB)

    Ohshita, T.; Oka, M.; Imon, Y.; Watanabe, C.; Katayama, S.; Yamaguchi, S. [Hiroshima Univ. (Japan). School of Medicine; Kajima, T.; Mimori, Y.; Nakamura, S.

    2000-09-01

    Clinical features of mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) resemble those of cerebral infarcts, but the pathogenesis of infarct-like lesions is not fully understood. To characterise these infarct-like lesions, we studied two patients with MELAS using diffusion-weighted (DWI) MRI before and after stroke-like episodes and measured the apparent diffusion coefficient (ADC) in the new infarct-like lesions. These gave high signal on DWI and had much higher ADC than normal-appearing regions. The ADC remained high even 30 days after a stroke-like episode then decreased in lesions, with or without abnormality as shown by conventional MRI. We speculate that early elevation of ADC in the acute or subacute phase reflects vasogenic rather than cytotoxic edema. The ADC of the lesions, which disappeared almost completely with clinical improvement, returned to normal levels, which may reflect tissue recovery without severe damage. To our knowledge, this is the first study of DWI in MELAS. (orig.)

  17. Diffusion-weighted MR imaging of the brain. 2. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Moritani, Toshio [Univ. of Iowa Hospitals and Clinics, Iowa City, IA (United States). Dept. of Radiology; Ekholm, Sven; Westesson, Per-Lennart [Rochester Univ. School of Medicine and Dentistry, Rochester, NY (United States). Div. of Diagnostic and Interventional Neuroradiology

    2009-07-01

    This practical-minded text helps the radiologist and the clinician understand diffusion-weighted MR imaging. The book's 15 chapters range from basic principles to interpretation of diffusion-weighted MR imaging and specific disease. In this second edition, diffusion tensor imaging (fractional anisotropy, color map and fiber tractography) is covered and a new chapter, on ''Diffusion-Weighted Imaging of Scalp and Skull Lesions,'' is included. The volume is updated by newly added cases accompanied by radiological and pathological images along with the most recent references. It is aimed at all those who are involved in neuroimaging, including: residents, fellows, staff, as well as neurologists and neurosurgeons. Diffusion-weighted MR imaging is widely accepted as a means to identify acute infarction but also to differentiate many other pathologic conditions. Understanding diffusion-weighted imaging is important for radiologists, neurologists, neurosurgeons as well as radiology technologists. (orig.)

  18. T2-enhanced tensor diffusion trace-weighted image in the detection of hyper-acute cerebral infarction: Comparison with isotropic diffusion-weighted image

    Energy Technology Data Exchange (ETDEWEB)

    Chou, M.-C. [Department of Radiology, Tri-Service General Hospital, Taipei, Taiwan (China); Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan (China); Tzeng, W.-S. [Department of Radiology, Chi-Mei Medical Center, Tainan, Taiwan (China); Chung, H.-W.; Wang, C.-Y.; Liu, H.-S.; Juan, C.-J. [Department of Radiology, Tri-Service General Hospital, Taipei, Taiwan, ROC (China); Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan (China); Lo, C.-P. [Department of Radiology, Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung, Taiwan (China); Hsueh, C.-J. [Department of Radiology, Tri-Service General Hospital, Taipei, Taiwan (China); Chen, C.-Y., E-mail: sandy0928@seed.net.t [Department of Radiology, Tri-Service General Hospital, Taipei, Taiwan (China)

    2010-06-15

    Background and purpose: Although isotropic diffusion-weighted imaging (isoDWI) is very sensitive to the detection of acute ischemic stroke, it may occasionally show diffusion negative result in hyper-acute stroke. We hypothesize that high diffusion contrast diffusion trace-weighted image with enhanced T2 may improve stroke lesion conspicuity. Methods: Five hyper acute stroke patients (M:F = 0:5, average age = 61.8 {+-} 20.5 y/o) and 16 acute stroke patients (M:F = 11:5, average age = 67.7 {+-} 12 y/o) were examined six-direction tensor DWIs at b = 707 s/mm{sup 2}. Three different diffusion-weighted images, including isotropic (isoDWI), diffusion trace-weighted image (trDWI) and T2-enhanced diffusion trace-weighted image (T2E{sub t}rDWI), were generated. Normalized lesion-to-normal ratio (nLNR) and contrast-to-noise ratio (CNR) of three diffusion images were calculated from each patient and statistically compared. Results: The trDWI shows better nLNR than isoDWI on both hyper-acute and acute stroke lesions, whereas no significant improvement in CNR. Nevertheless, the T2E{sub t}rDWI has statistically superior CNR and nLNR than those of isoDWI and trDWI in both hyper-acute and acute stroke. Conclusions: We concluded that tensor diffusion trace-weighted image with T2 enhancement is more sensitive to stroke lesion detection, and can provide higher lesion conspicuity than the conventional isotropic DWI for early stroke lesion delineation without the need of high-b-value technique.

  19. Diffusion filtering in image processing based on wavelet transform

    Institute of Scientific and Technical Information of China (English)

    LIU Feng

    2006-01-01

    The nonlinear diffusion filtering in image processing bases on the heat diffusion equations. Its key is the control of diffusion amount. In the previous models, the diffusivity depends on the gradients of images. So it is easily affected by noises. This paper first gives a new multiscale computational technique for diffusivity. Then we proposed a class of nonlinear wavelet diffusion (NWD) models that are used to restore images. The NWD model has strong ability to resist noise.But it, like the previous models, requires higher computational effort. Thus, by simplifying the NWD, we establish linear wavelet diffusion (LWD) models that consist of advection and diffusion. Since there exists the advection, the LWD filter is anisotropic, and hence can well preserve edges although the diffusion at edges is isotropic. The advantage is that the LWD model is easy to be analyzed and has lesser computational load. Finally, a variety of numerical experiments compared with the previous model are shown.

  20. Advanced and Conventional Magnetic Resonance Imaging in Neuropsychiatric Lupus.

    Science.gov (United States)

    Sarbu, Nicolae; Bargalló, Núria; Cervera, Ricard

    2015-01-01

    Neuropsychiatric lupus is a major diagnostic challenge, and a main cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Magnetic resonance imaging (MRI) is, by far, the main tool for assessing the brain in this disease. Conventional and advanced MRI techniques are used to help establishing the diagnosis, to rule out alternative diagnoses, and recently, to monitor the evolution of the disease. This review explores the neuroimaging findings in SLE, including the recent advances in new MRI methods.

  1. Pre- and post-operative diffusion tensor imaging of the median nerve in carpal tunnel syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Hiltunen, Jaana [Aalto University School of Science, Brain Research Unit, Low Temperature Laboratory, Aalto (Finland); Aalto University School of Science, Advanced Magnetic Imaging Centre, Aalto (Finland); Kirveskari, Erika [Aalto University School of Science, Brain Research Unit, Low Temperature Laboratory, Aalto (Finland); Helsinki University Central Hospital, Department of Clinical Neurophysiology, Helsinki (Finland); Numminen, Jussi [Aalto University School of Science, Brain Research Unit, Low Temperature Laboratory, Aalto (Finland); University of Helsinki, Helsinki Medical Imaging Center, Helsinki (Finland); Lindfors, Nina; Goeransson, Harry [Helsinki University Central Hospital, Department of Hand Surgery, Helsinki (Finland); Hari, Riitta [Aalto University School of Science, Brain Research Unit, Low Temperature Laboratory, Aalto (Finland); Aalto University School of Science, Advanced Magnetic Imaging Centre, Aalto (Finland); Helsinki University Central Hospital, Department of Clinical Neurophysiology, Helsinki (Finland)

    2012-06-15

    To use pre- and post-operative diffusion tensor imaging (DTI) to monitor median nerve integrity in patients suffering from carpal tunnel syndrome (CTS). Diffusivity and anisotropy images along the median nerve were compared among 12 patients, 12 age-matched and 12 young control subjects and correlated with electrophysiological neurography results. Slice-wise DTI parameter values were calculated to focus on local changes. Results of pre-operative patients and age-matched control subjects differed only in the distal nerve. Moreover, pre-operative patients differed significantly from young controls and post-operative patients. The main abnormalities were increased diffusivity and decreased anisotropy in the carpal tunnel and distal median nerve. Post-operative clinical improvement was reflected in diffusivity, but not in anisotropy. Slice-wise analysis showed high pre-operative diffusivity at the distal nerve. All groups had relatively large inter-subject variation in both diffusivity and anisotropy. DTI can provide information complementary to clinical examination, electrophysiological recordings and anatomical MRI of diseases and injuries of peripheral nerves. However, similar age-related changes in diffusivity and anisotropy may weaken DTI specificity. Slice-wise analysis is necessary for detection of local changes in nerve integrity. circle Diffusion tensor magnetic resonance imaging provides information complementary to conventional diagnostic methods. circle Age caused similar changes to diffusivity and anisotropy as carpal tunnel syndrome. circle Post-operative clinical improvement was reflected in diffusivity, but not in anisotropy. circle Inter-subject variation in diffusivity and anisotropy was considerable. (orig.)

  2. Neonatal hypoglycaemic encephalopathy: diffusion-weighted imaging and proton MR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, So Yeon; Goo, Hyun Woo [University of Ulsan College of Medicine, Department of Radiology, Asan Medical Center, Seoul (Korea); Lim, Keun Ho; Kim, Sang Tae [Asan Institute for Life Science, NMR Laboratory, Seoul (Korea); Kim, Ki Soo [University of Ulsan College of Medicine, Department of Neonatology, Asan Medical Center, Seoul (Korea)

    2006-02-01

    We report two infants with neonatal hypoglycaemic encephalopathy who were evaluated with diffusion-weighted imaging (DWI) and proton MR spectroscopy (MRS) as well as conventional MR. As in conventional MR, DWI and proton MRS revealed a predominance of abnormalities in the parieto-occipital lobes and underlying white matter including the splenium of the corpus callosum. In the acute phase of the disease, lesions on DWI showed restricted water diffusion and on DWI the characteristic lesions seemed to be more readily discernible than on conventional MRI. In the chronic phase, DWI demonstrated increased water diffusion in the affected areas showing atrophy on conventional MRI. Proton MRS revealed an increased lactate-lipid peak and a decreased NAA peak in the involved areas. DWI and proton MRS findings appear helpful in evaluating the extent and the presence of neuronal damage early in the course of neonatal hypoglycaemic encephalopathy. (orig.)

  3. Malignant versus benign mediastinal lesions: quantitative assessment with diffusion weighted MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Guemuestas, Sevtap; Inan, Nagihan; Sarisoy, Hasan Tahsin; Anik, Yonca; Arslan, Arzu; Ciftci, Ercuement; Akansel, Guer; Demirci, Ali [University of Kocaeli, Department of Radiology, School of Medicine, Umuttepe Kocaeli (Turkey)

    2011-11-15

    We aimed to evaluate the performance of diffusion-weighted magnetic resonance imaging in differentiating malignant from benign mediastinal lesions. Fifty-three mediastinal lesions were examined with T1- and T2-weighted (W) conventional images. Then, two diffusion-weighted images were obtained with b = 0 and 1000 s/mm{sup 2} values and apparent diffusion coefficients (ADC) were calculated. The statistical significance of differences between measurements was tested using the Student-t test. The mean ADC of malignant lesions was significantly lower than that of the benign masses (p < 0.001). The cut-off value of {<=} 1.39 x 10{sup -3} mm{sup 2}/s indicated a malignant lesion with a sensitivity of 95% and specificity of 87%. Diffusion-weighted imaging may be helpful in differentiating benign from malignant mediastinal masses. (orig.)

  4. Diffusion tensor imaging for target volume definition in glioblastoma multiforme

    Energy Technology Data Exchange (ETDEWEB)

    Berberat, Jatta; Remonda, Luca [Cantonal Hospital, Department of Neuro-radiology, Aarau (Switzerland); McNamara, Jane; Rogers, Susanne [Cantonal Hospital, Department of Radiation Oncology, Aarau (Switzerland); Bodis, Stephan [Cantonal Hospital, Department of Radiation Oncology, Aarau (Switzerland); University Hospital, Department of Radiation Oncology, Zurich (Switzerland)

    2014-10-15

    Diffusion tensor imaging (DTI) is an MR-based technique that may better detect the peritumoural region than MRI. Our aim was to explore the feasibility of using DTI for target volume delineation in glioblastoma patients. MR tensor tracts and maps of the isotropic (p) and anisotropic (q) components of water diffusion were coregistered with CT in 13 glioblastoma patients. An in-house image processing program was used to analyse water diffusion in each voxel of interest in the region of the tumour. Tumour infiltration was mapped according to validated criteria and contralateral normal brain was used as an internal control. A clinical target volume (CTV) was generated based on the T{sub 1}-weighted image obtained using contrast agent (T{sub 1Gd}), tractography and the infiltration map. This was compared to a conventional T{sub 2}-weighted CTV (T{sub 2}-w CTV). Definition of a diffusion-based CTV that included the adjacent white matter tracts proved highly feasible. A statistically significant difference was detected between the DTI-CTV and T{sub 2}-w CTV volumes (p < 0.005, t = 3.480). As the DTI-CTVs were smaller than the T{sub 2}-w CTVs (tumour plus peritumoural oedema), the pq maps were not simply detecting oedema. Compared to the clinical planning target volume (PTV), the DTI-PTV showed a trend towards volume reduction. These diffusion-based volumes were smaller than conventional volumes, yet still included sites of tumour recurrence. Extending the CTV along the abnormal tensor tracts in order to preserve coverage of the likely routes of dissemination, whilst sparing uninvolved brain, is a rational approach to individualising radiotherapy planning for glioblastoma patients. (orig.) [German] Die Diffusions-Tensor-Bildgebung (DTI) ist eine MR-Technik, die dank der Erfassung des peritumoralen Bereichs eine Verbesserung bezueglich MRI bringt. Unser Ziel war die Pruefung der Machbarkeit der Verwendung der DTI fuer die Zielvolumenabgrenzung fuer Patienten mit

  5. Diffusion tensor imaging of hippocampal network plasticity.

    Science.gov (United States)

    Sierra, Alejandra; Laitinen, Teemu; Gröhn, Olli; Pitkänen, Asla

    2015-03-01

    Diffusion tensor imaging (DTI) has become a valuable tool to investigate white matter integrity in the brain. DTI also gives contrast in gray matter, which has been relatively little explored in studies assessing post-injury structural abnormalities. The present study was designed to compare white and gray matter reorganization in the rat hippocampus after two epileptogenic brain injuries, status epilepticus (SE) and traumatic brain injury (TBI), using ex vivo high-resolution DTI. Imaging was performed at 6-12 months post-injury and findings were compared to histological analyses of Nissl, myelin, and Timm-stained preparations from the same animals. In agreement with the severity of histological damage, fractional anisotropy (FA), axial (D ||) and radial (D ⊥) diffusivities, and mean diffusivity (MD) measurements were altered in the order SE > TBI ipsilaterally > TBI contralaterally. After SE, the most severe abnormalities were found in the dentate gyrus and CA3b-c subfields, in which the mean FA was increased to 125 % (p < 0.001) and 143 % (p < 0.001) of that in controls, respectively. In both subfields, the change in FA was associated with an increase in D || (p < 0.01). In the stratum radiatum of the CA1, FA was decreased to 81 % of that in controls (p < 0.05) which was associated with an increase in D ⊥ (p < 0.01). After TBI, DTI did not reveal any major abnormalities in the dentate gyrus. In the ipsilateral CA3b-c, however, FA was increased to 126 % of that in controls (p < 0.01) and associated with a mild decrease in D ⊥ (p < 0.05). In the stratum radiatum of the ipsilateral CA1, FA was decreased to 88 % of that in controls (p < 0.05). Our data demonstrate that DTI reveals subfield-specific abnormalities in the hippocampus with remarkable qualitative and quantitative differences between the two epileptogenic etiologies, suggesting that DTI could be a valuable tool for follow-up of focal circuitry reorganization during the post

  6. Diagnosis of pericardial cysts using diffusion weighted magnetic resonance imaging: A case series

    Directory of Open Access Journals (Sweden)

    Mousavi Negareh

    2011-09-01

    Full Text Available Abstract Introduction Congenital pericardial cysts are benign lesions that arise from the pericardium during embryonic development. The diagnosis is based on typical imaging features, but atypical locations and signal magnetic resonance imaging sequences make it difficult to exclude other lesions. Diffusion-weighted magnetic resonance imaging is a novel method that can be used to differentiate tissues based on their restriction to proton diffusion. Its use in differentiating pericardial cysts from other pericardial lesions has not yet been described. Case presentation We present three cases (a 51-year-old Caucasian woman, a 66-year-old Caucasian woman and a 77-year-old Caucasian woman with pericardial cysts evaluated with diffusion-weighted imaging using cardiac magnetic resonance imaging. Each lesion demonstrated a high apparent diffusion coefficient similar to that of free water. Conclusion This case series is the first attempt to investigate the utility of diffusion-weighted magnetic resonance imaging in the assessment of pericardial cysts. Diffusion-weighted imaging may be a useful noninvasive diagnostic tool for pericardial cysts when conventional imaging findings are inconclusive.

  7. High spatial resolution diffusion tensor imaging and its applications

    CERN Document Server

    Wang, J J

    2002-01-01

    Introduction Magnetic Resonance Imaging is at present the only imaging technique available to measure diffusion of water and metabolites in humans. It provides vital insights to brain connectivity and has proved to be an important tool in diagnosis and therapy planning in many neurological diseases such as brain tumour, ischaemia and multiple sclerosis. This project focuses on the development of a high resolution diffusion tensor imaging technique. In this thesis, the basic theory of diffusion tensor MR Imaging is presented. The technical challenges encountered during development of these techniques will be discussed, with proposed solutions. New sequences with high spatial resolution have been developed and the results are compared with the standard technique more commonly used. Overview The project aims at the development of diffusion tensor imaging techniques with a high spatial resolution. Chapter 2 will describe the basic physics of MRI, the phenomenon of diffusion and the measurement of diffusion by MRI...

  8. Diffusion tensor imaging of post mortem multiple sclerosis brain.

    Science.gov (United States)

    Schmierer, Klaus; Wheeler-Kingshott, Claudia A M; Boulby, Phil A; Scaravilli, Francesco; Altmann, Daniel R; Barker, Gareth J; Tofts, Paul S; Miller, David H

    2007-04-01

    Magnetic resonance imaging (MRI) is being used to probe the central nervous system (CNS) of patients with multiple sclerosis (MS), a chronic demyelinating disease. Conventional T(2)-weighted MRI (cMRI) largely fails to predict the degree of patients' disability. This shortcoming may be due to poor specificity of cMRI for clinically relevant pathology. Diffusion tensor imaging (DTI) has shown promise to be more specific for MS pathology. In this study we investigated the association between histological indices of myelin content, axonal count and gliosis, and two measures of DTI (mean diffusivity [MD] and fractional anisotropy [FA]), in unfixed post mortem MS brain using a 1.5-T MR system. Both MD and FA were significantly lower in post mortem MS brain compared to published data acquired in vivo. However, the differences of MD and FA described in vivo between white matter lesions (WMLs) and normal-appearing white matter (NAWM) were retained in this study of post mortem brain: average MD in WMLs was 0.35x10(-3) mm(2)/s (SD, 0.09) versus 0.22 (0.04) in NAWM; FA was 0.22 (0.06) in WMLs versus 0.38 (0.13) in NAWM. Correlations were detected between myelin content (Tr(myelin)) and (i) FA (r=-0.79, ppost mortem MS brain.

  9. Diffusion-weighted imaging in characterization of cystic pancreatic lesions

    Energy Technology Data Exchange (ETDEWEB)

    Sandrasegaran, K., E-mail: ksandras@iupui.edu [Department of Radiology, Indiana University School of Medicine, Indianapolis, IN (United States); Akisik, F.M.; Patel, A.A.; Rydberg, M. [Department of Radiology, Indiana University School of Medicine, Indianapolis, IN (United States); Cramer, H.M.; Agaram, N.P. [Department of Pathology, Indiana University School of Medicine, Indianapolis, IN (United States); Schmidt, C.M. [Department of Surgery, Indiana University School of Medicine, Indianapolis, IN (United States)

    2011-09-15

    Aim: To evaluate whether apparent diffusion coefficient (ADC) measurements from diffusion-weighted imaging (DWI) can characterize or predict the malignant potential of cystic pancreatic lesions. Materials and methods: Retrospective review of the magnetic resonance imaging (MRI) database over a 2-year period revealed 136 patients with cystic pancreatic lesions. Patients with DWI studies and histological confirmation of cystic mass were included. In patients with known pancreatitis, lesions with amylase content of >1000 IU/l that resolved on subsequent scans were included as pseudocysts. ADC of cystic lesions was measured by two independent reviewers. These values were then compared to categorize these lesions as benign or malignant using conventional MRI sequences. Results: Seventy lesions were analysed: adenocarcinoma (n = 4), intraductal papillary mucinous neoplasm (IPMN; n = 28), mucinous cystic neoplasm (MCN; n = 9), serous cystadenoma (n = 16), and pseudocysts (n = 13). There was no difference between ADC values of malignant and non-malignant lesions (p = 0.06), between mucinous and serous tumours (p = 0.12), or between IPMN and MCN (p = 0.42). ADC values for low-grade IPMN were significantly higher than those for high-grade or invasive IPMN (p = 0.03). Conclusion: ADC values may be helpful in deciding the malignant potential of IPMN. However, they are not useful in differentiating malignant from benign lesions or for characterizing cystic pancreatic lesions.

  10. Diffusion-weighted imaging in normal fetal brain maturation

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, J.F. [University Children' s Hospital UKBB, Department of Pediatric Radiology, Basel (Switzerland); Confort-Gouny, S.; Le Fur, Y.; Viout, P.; Cozzone, P. [UMR-CNRS 6612, Faculte de Medecine, Universite de la Mediterranee, Centre de Resonance Magnetique Biologique et Medicale, Marseille (France); Bennathan, M.; Chapon, F.; Fogliarini, C.; Girard, N. [Universite de la Mediterranee, Department of Neuroradiology AP-HM Timone, Marseille (France)

    2007-09-15

    Diffusion-weighted imaging (DWI) provides information about tissue maturation not seen on conventional magnetic resonance imaging. The aim of this study is to analyze the evolution over time of the apparent diffusion coefficient (ADC) of normal fetal brain in utero. DWI was performed on 78 fetuses, ranging from 23 to 37 gestational weeks (GW). All children showed at follow-up a normal neurological evaluation. ADC values were obtained in the deep white matter (DWM) of the centrum semiovale, the frontal, parietal, occipital and temporal lobe, in the cerebellar hemisphere, the brainstem, the basal ganglia (BG) and the thalamus. Mean ADC values in supratentorial DWM areas (1.68 {+-} 0.05 mm{sup 2}/s) were higher compared with the cerebellar hemisphere (1.25 {+-} 0.06 mm{sup 2}/s) and lowest in the pons (1.11 {+-} 0.05 mm{sup 2}/s). Thalamus and BG showed intermediate values (1.25 {+-} 0.04 mm{sup 2}/s). Brainstem, cerebellar hemisphere and thalamus showed a linear negative correlation with gestational age. Supratentorial areas revealed an increase in ADC values, followed by a decrease after the 30th GW. This study provides a normative data set that allows insights in the normal fetal brain maturation in utero, which has not yet been observed in previous studies on premature babies. (orig.)

  11. Is diffusion weighted imaging adding value in diagnosis of focal ...

    African Journals Online (AJOL)

    Doaa Mokhtar Mohamed Emara

    2013-05-09

    May 9, 2013 ... Abstract Introduction: Diffusion weighted imaging (DWI) offers molecular information that ... model, the effect of the first (dephasing) gradient is cancelled ... Areas of true restricted diffusion demonstrate high signal ... A phased array surface coil was ..... signal intensity ratios with small diffusion gradients for.

  12. Effects of microperfusion in hepatic diffusion weighted imaging

    NARCIS (Netherlands)

    Dijkstra, Hildebrand; Baron, Paul; Kappert, Peter; Oudkerk, Matthijs; Sijens, Paul E.

    2012-01-01

    Clinical hepatic diffusion weighted imaging (DWI) generally relies on mono-exponential diffusion. The aim was to demonstrate that mono-exponential diffusion in the liver is contaminated by microperfusion and that the bi-exponential model is required. Nineteen fasting healthy volunteers were examined

  13. Effects of microperfusion in hepatic diffusion weighted imaging

    NARCIS (Netherlands)

    Dijkstra, Hildebrand; Baron, Paul; Kappert, Peter; Oudkerk, Matthijs; Sijens, Paul E.

    Clinical hepatic diffusion weighted imaging (DWI) generally relies on mono-exponential diffusion. The aim was to demonstrate that mono-exponential diffusion in the liver is contaminated by microperfusion and that the bi-exponential model is required. Nineteen fasting healthy volunteers were examined

  14. Diffusion Tensor Imaging of TBI: Potentials and Challenges.

    Science.gov (United States)

    Douglas, David B; Iv, Michael; Douglas, Pamela K; Anderson, Ariana; Vos, Sjoerd B; Bammer, Roland; Zeineh, Michael; Wintermark, Max

    2015-10-01

    Neuroimaging plays a critical role in the setting in traumatic brain injury (TBI). Diffusion tensor imaging (DTI) is an advanced magnetic resonance imaging technique that is capable of providing rich information on the brain's neuroanatomic connectome. The purpose of this article is to systematically review the role of DTI and advanced diffusion techniques in the setting of TBI, including diffusion kurtosis imaging (DKI), neurite orientation dispersion and density imaging, diffusion spectrum imaging, and q-ball imaging. We discuss clinical applications of DTI and review the DTI literature as it pertains to TBI. Despite the continued advancements in DTI and related diffusion techniques over the past 20 years, DTI techniques are sensitive for TBI at the group level only and there is insufficient evidence that DTI plays a role at the individual level. We conclude by discussing future directions in DTI research in TBI including the role of machine learning in the pattern classification of TBI.

  15. Diffusion MR Imaging of Postoperative Bilateral Acute Ischemic Optic Neuropathy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ju Young; Lee, In Ho; Song, Chang June [Chungnam National University Hospital, Daejeon (Korea, Republic of); Hwang, Hee Youn [Eulji University Hospital, Daejeon(Korea, Republic of)

    2012-03-15

    A 57-year-old woman experienced bilateral acute ischemic optic neuropathy after spine surgery. Routine MR imaging sequence, T2-weighted image, showed subtle high signal intensity on bilateral optic nerves. A contrast-enhanced T1 weighted image showed enhancement along the bilateral optic nerve sheath. Moreover, diffusion-weighted image (DWI) and an apparent diffusion coefficient map showed markedly restricted diffusion on bilateral optic nerves. Although MR findings of T2-weighted and contrast enhanced T1-weighted images may be nonspecific, the DWI finding of cytotoxic edema of bilateral optic nerves will be helpful for the diagnosis of acute ischemic optic neuropathy after spine surgery.

  16. Stereotactic diffusion tensor imaging tractography for Gamma Knife radiosurgery.

    Science.gov (United States)

    Gavin, Cormac G; Ian Sabin, H

    2016-12-01

    OBJECTIVE The integration of modern neuroimaging into treatment planning has increased the therapeutic potential and safety of stereotactic radiosurgery. The authors report their method of integrating stereotactic diffusion tensor imaging (DTI) tractography into conventional treatment planning for Gamma Knife radiosurgery (GKRS). The aim of this study was to demonstrate the feasibility of this technique and to address some of the technical limitations of previously reported techniques. METHODS Twenty patients who underwent GKRS composed the study cohort. They consisted of 1 initial test case (a patient with a vestibular schwannoma), 5 patients with arteriovenous malformations, 9 patients with cerebral metastases, 1 patient with parasagittal meningioma, and 4 patients with vestibular schwannoma. DT images were obtained at the time of standard GKRS protocol MRI (T1 and T2 weighted) for treatment, with the patient's head secured by a Leksell stereotactic frame. All studies were performed using a 1.5-T magnet with a single-channel head coil. DTI was performed with diffusion gradients in 32 directions and coregistered with the volumetric T1-weighted study. DTI postprocessing by means of commercially available software allowed tensor computation and the creation of directionally encoded color-, apparent diffusion coefficient-, and fractional anisotropy-mapped sequences. In addition, the software allowed visualized critical tracts to be exported as a structural volume and integrated into GammaPlan as an "organ at risk" during shot planning. Combined images were transferred to GammaPlan and integrated into treatment planning. RESULTS Stereotactic DT images were successfully acquired in all patients, with generation of correct directionally encoded color images. Tract generation with the software was straightforward and reproducible, particularly for axial tracts such as the optic radiation and the arcuate fasciculus. Corticospinal tract visualization was hampered by some

  17. Diffusion-weighted MR imaging findings in a patient with herpes simplex encephalitis

    Energy Technology Data Exchange (ETDEWEB)

    Heiner, L. E-mail: heiner_lajos@freemail.hu; Demaerel, Ph

    2003-03-01

    Introduction: Herpes simplex meningoencephalitis is one of the most common viral central nervous system infection in adults. Early diagnosis is essential for treatment. Case report: We present a case of a 68-year-old female patient with herpes simplex infection. On admission, she was in severe clinical condition. Diffusion-weighted (DW) magnetic resonance imaging detected brain involvement better than conventional sequences. After acyclovir therapy, the patient fully recovered. Conclusion: DW magnetic resonance imaging is expected to provide a more sensitive imaging in herpes simplex patients than conventional sequences.

  18. Diffusion tensor imaging and histology of developing hearts.

    Science.gov (United States)

    Abdullah, Osama M; Seidel, Thomas; Dahl, MarJanna; Gomez, Arnold David; Yiep, Gavin; Cortino, Julia; Sachse, Frank B; Albertine, Kurt H; Hsu, Edward W

    2016-10-01

    Diffusion tensor imaging (DTI) has emerged as a promising method for noninvasive quantification of myocardial microstructure. However, the origin and behavior of DTI measurements during myocardial normal development and remodeling remain poorly understood. In this work, conventional and bicompartmental DTI in addition to three-dimensional histological correlation were performed in a sheep model of myocardial development from third trimester to postnatal 5 months of age. Comparing the earliest time points in the third trimester with the postnatal 5 month group, the scalar transverse diffusivities preferentially increased in both left ventricle (LV) and right ventricle (RV): secondary eigenvalues D2 increased by 54% (LV) and 36% (RV), whereas tertiary eigenvalues D3 increased by 85% (LV) and 67% (RV). The longitudinal diffusivity D1 changes were small, which led to a decrease in fractional anisotropy by 41% (LV) and 33% (RV) in 5 month versus fetal hearts. Histological analysis suggested that myocardial development is associated with hyperplasia in the early stages of the third trimester followed by myocyte growth in the later stages up to 5 months of age (increased average myocyte width by 198%, myocyte length by 128%, and decreased nucleus density by 70% between preterm and postnatal 5 month hearts.) In a few histological samples (N = 6), correlations were observed between DTI longitudinal diffusivity and myocyte length (r = 0.86, P eigenvectors during development changed significantly. Collectively, the findings demonstrate a role for DTI to monitor and quantify myocardial development, and potentially cardiac disease. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Reduction of noise in diffusion tensor images using anisotropic smoothing.

    Science.gov (United States)

    Ding, Zhaohua; Gore, John C; Anderson, Adam W

    2005-02-01

    To improve the accuracy of tissue structural and architectural characterization with diffusion tensor imaging, a novel smoothing technique is developed for reducing noise in diffusion tensor images. The technique extends the traditional anisotropic diffusion filtering method by allowing isotropic smoothing within homogeneous regions and anisotropic smoothing along structure boundaries. This is particularly useful for smoothing diffusion tensor images in which direction information contained in the tensor needs to be restored following noise corruption and preserved around tissue boundaries. The effectiveness of this technique is quantitatively studied with experiments on simulated and human in vivo diffusion tensor data. Illustrative results demonstrate that the anisotropic smoothing technique developed can significantly reduce the impact of noise on the direction as well as anisotropy measures of the diffusion tensor images.

  20. Accelerated diffusion spectrum imaging via compressed sensing for the human connectome project

    Science.gov (United States)

    Lee, Namgyun; Wilkins, Bryce; Singh, Manbir

    2012-02-01

    Diffusion Spectrum Imaging (DSI) has been developed as a model-free approach to solving the so called multiple-fibers-per- voxel problem in diffusion MRI. However, inferring heterogeneous microstructures of an imaging voxel rapidly remains a challenge in DSI because of extensive sampling requirements in a Cartesian grid of q-space. In this study, we propose compressed sensing based diffusion spectrum imaging (CS-DSI) to significantly reduce the number of diffusion measurements required for accurate estimation of fiber orientations. This method reconstructs each diffusion propagator of an MR data set from 100 variable density undersampled diffusion measurements minimizing the l1-norm of the finite-differences (i.e.,anisotropic total variation) of the diffusion propagator. The proposed method is validated against a ground truth from synthetic data mimicking the FiberCup phantom, demonstrating the robustness of CS-DSI on accurately estimating underlying fiber orientations from noisy diffusion data. We demonstrate the effectiveness of our CS-DSI method on a human brain dataset acquired from a clinical scanner without specialized pulse sequences. Estimated ODFs from CS-DSI method are qualitatively compared to those from the full dataset (DSI203). Lastly, we demonstrate that streamline tractography based on our CS-DSI method has a comparable quality to conventional DSI203. This illustrates the feasibility of CS-DSI for reconstructing whole brain white-matter fiber tractography from clinical data acquired at imaging centers, including hospitals, for human brain connectivity studies.

  1. Bayesian regularization of diffusion tensor images

    DEFF Research Database (Denmark)

    Frandsen, Jesper; Hobolth, Asger; Østergaard, Leif;

    2007-01-01

    several directions. The measured diffusion coefficients and thereby the diffusion tensors are subject to noise, leading to possibly flawed representations of the three dimensional fibre bundles. In this paper we develop a Bayesian procedure for regularizing the diffusion tensor field, fully utilizing...

  2. Refocusing images and videos with a conventional compact camera

    Science.gov (United States)

    Kang, Lai; Wu, Lingda; Wei, Yingmei; Song, Hanchen; Yang, Zheng

    2015-03-01

    Digital refocusing is an interesting and useful tool for generating dynamic depth-of-field (DOF) effects in many types of photography such as portraits and creative photography. Since most existing digital refocusing methods rely on four-dimensional light field captured by special precisely manufactured devices or a sequence of images captured by a single camera, existing systems are either expensive for wide practical use or incapable of handling dynamic scenes. We present a low-cost approach for refocusing high-resolution (up to 8 mega pixels) images and videos based on a single shot using an easy to build camera-mirror stereo system. Our proposed method consists of four main steps, namely system calibration, image rectification, disparity estimation, and refocusing rendering. The effectiveness of our proposed method has been evaluated extensively using both static and dynamic scenes with various depth ranges. Promising experimental results demonstrate that our method is able to simulate various controllable realistic DOF effects. To the best of our knowledge, our method is the first that allows one to refocus high-resolution images and videos of dynamic scenes captured by a conventional compact camera.

  3. 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

  4. Diffusion-weighted magnetic resonance imaging of the ulnar nerve in cubital tunnel syndrome.

    Science.gov (United States)

    Iba, K; Wada, T; Tamakawa, M; Aoki, M; Yamashita, T

    2010-01-01

    Diffusion-weighted images based on magnetic resonance reveal the microstructure of tissues by monitoring the random movement of water molecules. In this study, we investigated whether this new technique could visualize pathologic lesions on ulnar nerve in cubital tunnel. Six elbows in six healthy males without any symptoms and eleven elbows in ten patients with cubital tunnel syndrome underwent on diffusion-weighted MRI. No signal from the ulnar nerve was detected in normal subjects. Diffusion-weighted MRI revealed positive signals from the ulnar nerve in all of the eleven elbows with cubital tunnel syndrome. In contrast, conventional T2W-MRI revealed high signal intensity in eight elbows and low signal intensity in three elbows. Three elbows with low signal MRI showed normal nerve conduction velocity of the ulnar nerve. Diffusion-weighted MRI appears to be an attractive technique for diagnosis of cubital tunnel syndrome in its early stages which show normal electrophysiological and conventional MRI studies.

  5. Diffusion tensor MR imaging in spinal cord injury.

    Science.gov (United States)

    D'souza, Maria M; Choudhary, Ajay; Poonia, Mahesh; Kumar, Pawan; Khushu, Subash

    2017-04-01

    The ability of diffusion tensor imaging (DTI) to complement conventional MR imaging by diagnosing subtle injuries to the spinal cord is a subject of intense research. We attempted to study change in the DTI indices, namely fractional anisotropy (FA) and mean diffusivity (MD) after traumatic cervical spinal cord injury and compared these with corresponding data from a control group of individuals with no injury. The correlation of these quantitative indices to the neurological profile of the patients was assessed. 20 cases of acute cervical trauma and 30 age and sex matched healthy controls were enrolled. Scoring of extent of clinical severity was done based on the Frankel grading system. MRI was performed on a 3T system. Following the qualitative tractographic evaluation of white matter tracts, quantitative datametrics were calculated. In patients, the Mean FA value at the level of injury (0.43+/-0.08) was less than in controls (0.62+/-0.06), which was statistically significant (p value injury (1.30+/-0.24) in cases was higher than in controls (1.07+/-0.12, p value injury (r value=0.86). Negative correlation was found between clinical grade and Mean MD at the level of injury (r value=-0.38) which was however statistically not significant. Quantitative DTI indices are a useful parameter for detection of spinal cord injury. FA value was significantly decreased while MD value was significantly increased at the level of injury in cases as compared to controls. Further, FA showed significant correlation with clinical grade. DTI could thus serve as a reliable objective imaging tool for assessment of white matter integrity and prognostication of functional outcome. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Wavelet-Based Diffusion Approach for DTI Image Restoration

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiang-fen; CHEN Wu-fan; TIAN Wei-feng; YE Hong

    2008-01-01

    The Rician noise introduced into the diffusion tensor images (DTIs) can bring serious impacts on tensor calculation and fiber tracking. To decrease the effects of the Rician noise, we propose to consider the wavelet-based diffusion method to denoise multichannel typed diffusion weighted (DW) images. The presented smoothing strategy, which utilizes anisotropic nonlinear diffusion in wavelet domain, successfully removes noise while preserving both texture and edges. To evaluate quantitatively the efficiency of the presented method in accounting for the Rician noise introduced into the DW images, the peak-to-peak signal-to-noise ratio (PSNR) and signal-to-mean squared error ratio (SMSE) metrics are adopted. Based on the synthetic and real data, we calculated the apparent diffusion coefficient (ADC) and tracked the fibers. We made comparisons between the presented model,the wave shrinkage and regularized nonlinear diffusion smoothing method. All the experiment results prove quantitatively and visually the better performance of the presented filter.

  7. Imaging diffusion in a microfluidic device by third harmonic microscopy

    Science.gov (United States)

    Petzold, Uwe; Büchel, Andreas; Hardt, Steffen; Halfmann, Thomas

    2012-09-01

    We monitor and characterize near-surface diffusion of miscible, transparent liquids in a microfluidic device by third harmonic microscopy. The technique enables observations even of transparent or index-matched media without perturbation of the sample. In particular, we image concentrations of ethanol diffusing in water and estimate the diffusion coefficient from the third harmonic images. We obtain a diffusion coefficient D = (460 ± 30) μm2/s, which is consistent with theoretical predictions. The investigations clearly demonstrate the potential of harmonic microscopy also under the challenging conditions of transparent fluids.

  8. Comparative study between conventional and diffusion-bonded Nd-doped vanadate crystals in the passively mode-locked operation.

    Science.gov (United States)

    Huang, Y J; Huang, Y P; Liang, H C; Su, K W; Chen, Y F; Huang, K F

    2010-04-26

    We design a reliable linear three-element cavity to make a comparative study between the conventional and diffusion-bonded Nd:GdVO(4) crystals in the passively mode-locked operation. Experimental investigations reveal that the mode-locked pulse width obtained with the diffusion-bonded crystal is considerably broader than that obtained with the conventional crystal, even though the diffusion-bonded crystal can significantly reduce the thermal effects. The pulse broadening is experimentally verified to come from the length of the undoped part that brings in a reduction of the spatial-hole-burning (SHB) effect.

  9. Image Quality Modeling and Optimization for Non-Conventional Aperture Imaging Systems

    Science.gov (United States)

    Salvaggio, Philip S.

    The majority of image quality studies have been performed on systems with conventional aperture functions. These systems have straightforward aperture designs and well-understood behavior. Image quality for these systems can be predicted by the General Image Quality Equation (GIQE). However, in order to continue pushing the boundaries of imaging, more control over the point spread function of an imaging system may be necessary. This requires modifications in the pupil plane of a system, causing a departure from the realm of most image quality studies. Examples include sparse apertures, synthetic apertures, coded apertures and phase elements. This work will focus on sparse aperture telescopes and the image quality issues associated with them, however, the methods presented will be applicable to other non-conventional aperture systems. In this research, an approach for modeling the image quality of non-conventional aperture systems will be introduced. While the modeling approach is based in previous work, a novel validation study will be performed, which accounts for the effects of both broadband illumination and wavefront error. One of the key image quality challenges for sparse apertures is post-processing ringing artifacts. These artifacts have been observed in modeled data, but a validation study will be performed to observe them in measured data and to compare them to model predictions. Once validated, the modeling approach will be used to perform a small set of design studies for sparse aperture systems, including spectral bandpass selection and aperture layout optimization.

  10. Hypofractionation vs Conventional Radiation Therapy for Newly Diagnosed Diffuse Intrinsic Pontine Glioma: A Matched-Cohort Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Janssens, Geert O., E-mail: g.janssens@rther.umcn.nl [Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Jansen, Marc H. [Pediatric Oncology/Hematology, VU University Medical Center, Amsterdam (Netherlands); Lauwers, Selmer J. [Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Nowak, Peter J. [Department of Radiation Oncology, Erasmus Medical Centre, Rotterdam (Netherlands); Oldenburger, Foppe R. [Department of Radiation Oncology, Academic Medical Centre, Amsterdam (Netherlands); Bouffet, Eric [Department of Hematology/Oncology, The Hospital for Sick Children, University of Toronto, Toronto (Canada); Saran, Frank [Department of Pediatric Oncology, The Royal Marsden NHS Foundation Trust, Sutton (United Kingdom); Kamphuis-van Ulzen, Karin [Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Lindert, Erik J. van [Department of Neurosurgery, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Schieving, Jolanda H. [Department of Neurology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Boterberg, Tom [Department of Radiation Oncology, Ghent University Hospital, Ghent (Belgium); Kaspers, Gertjan J. [Pediatric Oncology/Hematology, VU University Medical Center, Amsterdam (Netherlands); Span, Paul N.; Kaanders, Johannes H. [Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Gidding, Corrie E. [Department of Pediatric Oncology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Hargrave, Darren [Department of Oncology, Great Ormond Street Hospital, London (United Kingdom)

    2013-02-01

    Purpose: Despite conventional radiation therapy, 54 Gy in single doses of 1.8 Gy (54/1.8 Gy) over 6 weeks, most children with diffuse intrinsic pontine glioma (DIPG) will die within 1 year after diagnosis. To reduce patient burden, we investigated the role of hypofractionation radiation therapy given over 3 to 4 weeks. A 1:1 matched-cohort analysis with conventional radiation therapy was performed to assess response and survival. Methods and Materials: Twenty-seven children, aged 3 to 14, were treated according to 1 of 2 hypofractionation regimens over 3 to 4 weeks (39/3 Gy, n=16 or 44.8/2.8 Gy, n=11). All patients had symptoms for {<=}3 months, {>=}2 signs of the neurologic triad (cranial nerve deficit, ataxia, long tract signs), and characteristic features of DIPG on magnetic resonance imaging. Twenty-seven patients fulfilling the same diagnostic criteria and receiving at least 50/1.8 to 2.0 Gy were eligible for the matched-cohort analysis. Results: With hypofractionation radiation therapy, the overall survival at 6, 9, and 12 months was 74%, 44%, and 22%, respectively. Progression-free survival at 3, 6, and 9 months was 77%, 43%, and 12%, respectively. Temporary discontinuation of steroids was observed in 21 of 27 (78%) patients. No significant difference in median overall survival (9.0 vs 9.4 months; P=.84) and time to progression (5.0 vs 7.6 months; P=.24) was observed between hypofractionation vs conventional radiation therapy, respectively. Conclusions: For patients with newly diagnosed DIPG, a hypofractionation regimen, given over 3 to 4 weeks, offers equal overall survival with less treatment burden compared with a conventional regimen of 6 weeks.

  11. MR diffusion imaging of human intracranial tumours

    DEFF Research Database (Denmark)

    Krabbe, K; Gideon, P; Wagn, P;

    1997-01-01

    We used MRI for in vivo measurement of brain water self-diffusion in patients with intracranial tumours. The study included 28 patients (12 with high-grade and 3 with low-grade gliomas, 7 with metastases, 5 with meningiomas and 1 with a cerebral abscess). Apparent diffusion coefficients (ADC) wer...

  12. Diagnostic performance of conventional MRI parameters and apparent diffusion coefficient values in differentiating between benign and malignant soft-tissue tumours.

    Science.gov (United States)

    Song, Y; Yoon, Y C; Chong, Y; Seo, S W; Choi, Y-L; Sohn, I; Kim, M-J

    2017-08-01

    To compare the abilities of conventional magnetic resonance imaging (MRI) and apparent diffusion coefficient (ADC) in differentiating between benign and malignant soft-tissue tumours (STT). A total of 123 patients with STT who underwent 3 T MRI, including diffusion-weighted imaging (DWI), were retrospectively analysed using variate conventional MRI parameters, ADCmean and ADCmin. For the all-STT group, the correlation between the malignant STT conventional MRI parameters, except deep compartment involvement, compared to those of benign STT were statistically significant with univariate analysis. Maximum diameter of the tumour (p=0.001; odds ratio [OR], 8.97) and ADCmean (p=0.020; OR, 4.30) were independent factors with multivariate analysis. For the non-myxoid non-haemosiderin STT group, signal heterogeneity on axial T1-weighted imaging (T1WI; p=0.017), ADCmean, and ADCmin (p=0.001, p=0.001), showed significant differences with univariate analysis between malignancy and benignity. Signal heterogeneity in axial T1WI (p=0.025; OR, 12.64) and ADCmean (p=0.004; OR, 33.15) were independent factors with multivariate analysis. ADC values as well as conventional MRI parameters were useful in differentiating between benign and malignant STT. The ADCmean was the most powerful diagnostic parameter in non-myxoid non-haemosiderin STT. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  13. Diffusion and Perfusion Magnetic Resonance Imaging:Fundamentals and Advances

    CERN Document Server

    Assili, Sanam

    2016-01-01

    Over the past few decades, magnetic resonance imaging has been utilized as a powerful imaging modality to evaluate the structure and function of various organs in the human body,such as the brain. Additionally, diffusion and perfusion MR imaging have been increasingly used in neurovascular clinical applications. In diffusion-weighted magnetic resonance imaging, the mobility of water molecules is explored in order to obtain information about the microscopic behavior of the tissues. In contrast, perfusion weighted imaging uses tracers to exploit hemodynamic status, which enables researchers and clinicians to consider this imaging modality as an early biomarker of certain brain diseases. In this review, the fundamentals of physics for diffusion and perfusion MR imaging both of which are highly sensitive to microenvironmental alterations at the cellular level as well as their application in the treatment of aging, Alzheimer's disease, brain tumors and cerebral ischemic injury were discussed.

  14. Diffusion in Altered Tonalite Sample Using Time Domain Diffusion Simulations in Tomographic Images Combined with Lab-scale Diffusion Experiments

    Science.gov (United States)

    Voutilainen, M.; Sardini, P.; Togneri, L.; Siitari-Kauppi, M.; Timonen, J.

    2010-12-01

    In this work an effect of rock heterogeneity on diffusion was investigated. Time domain diffusion simulations were used to compare behavior of diffusion in homogeneous and heterogeneous 3D media. Tomographic images were used as heterogeneous rock media. One altered tonalite sample from Sievi, Finland, was chosen as test case for introduced analysis procedure. Effective diffusion coefficient of tonalite sample was determined with lab-scale experiments and the same coefficient was used also for homogeneous media. Somewhat technically complicated mathematical solution for analysis of through diffusion experiment is shortly described. Computed tomography (CT) is already quite widely used in many geological, petrological, and paleontological applications when the three-dimensional (3D) structure of the material is of interest, and is an excellent method for gaining information especially about its heterogeneity, grain size, or porosity. In addition to offering means for quantitative characterization, CT provides a lot of qualitative information [1]. A through -diffusion laboratory experiment using radioactive tracer was fitted using the Time Domain Diffusion (TDD) method. This rapid particle tracking method allows simulation of the heterogeneous diffusion based on pore-scale images and local values of diffusivities [2]. As a result we found out that heterogeneity has only a small effect to diffusion coefficient and in-diffusion profile for used geometry. Also direction dependency was tested and was found to be negligible. Whereas significant difference between generally accepted value and value obtained from simulations for constant m in Archie’s law was found. [1] Voutilainen, M., Siitari-Kauppi, M., Sardini, P., and Timonen, J., (2010). On pore-space characterization of an altered tonalite by X-ray µCT and the 14C-PMMA method (in progress). [2] Sardini, P., Robinet, J., Siitari-Kauppi, M., Delay, F., and Hellmuth, K-H, (2007). On direct simulation of heterogeneous

  15. Diffusion imaging with stimulated echoes: signal models and experiment design

    CERN Document Server

    Alexander, Daniel C

    2013-01-01

    Purpose: Stimulated echo acquisition mode (STEAM) diffusion MRI can be advantageous over pulsed-gradient spin-echo (PGSE) for diffusion times that are long compared to $\\ttwo$. It is important therefore for biomedical diffusion imaging applications at 7T and above where $\\ttwo$ is short. However, imaging gradients in the STEAM sequence contribute much greater diffusion weighting than in PGSE, but are often ignored during post-processing. We demonstrate here that this can severely bias parameter estimates. Method: We present models for the STEAM signal for free and restricted diffusion that account for crusher and slice-select (butterfly) gradients to avoid such bias. The butterfly gradients also disrupt experiment design, typically by skewing gradient-vectors towards the slice direction. We propose a simple compensation to the diffusion gradient vector specified to the scanner that counterbalances the butterfly gradients to preserve the intended experiment design. Results: High-field data fixed monkey brain e...

  16. High angular resolution diffusion imaging with stimulated echoes

    DEFF Research Database (Denmark)

    Lundell, Henrik; Alexander, Daniel C; Dyrby, Tim B

    2014-01-01

    other than the diffusion gradients in the STEAM sequence contribute much greater diffusion weighting than in PGSE and lead to a disrupted experimental design. Here, we introduce a simple compensation to the STEAM acquisition that avoids the orientational bias and disrupted experiment design...... that these gradient pulses can otherwise produce. The compensation is simple to implement by adjusting the gradient vectors in the diffusion pulses of the STEAM sequence, so that the net effective gradient vector including contributions from diffusion and other gradient pulses is as the experiment intends. High...... angular resolution diffusion imaging (HARDI) data were acquired with and without the proposed compensation. The data were processed to derive standard diffusion tensor imaging (DTI) maps, which highlight the need for the compensation. Ignoring the other gradient pulses, a bias in DTI parameters from STEAM...

  17. NMR-Based Diffusion Lattice Imaging

    CERN Document Server

    Laun, Frederik Bernd

    2013-01-01

    Nuclear magnetic resonance (NMR) diffusion experiments are widely employed as they yield information about structures hindering the diffusion process, e.g. about cell membranes. While it has been shown in recent articles, that these experiments can be used to determine the exact shape of closed pores averaged over a volume of interest, it is still an open question how much information can be gained in open systems. In this theoretical work, we show that the full structure information of periodic open systems is accessible. To this end, the so-called 'SEquential Rephasing by Pulsed field-gradient Encoding N Time-intervals' (SERPENT) sequence is used, which employs several diffusion weighting gradient pulses with different amplitudes. The structural information is obtained by an iterative technique relying on a Gaussian envelope model of the diffusion propagator. Two solid matrices that are surrounded by an NMR-visible medium are considered: a hexagonal lattice of cylinders and a cubic lattice of triangles.

  18. Correlation of proton MR spectroscopy and diffusion tensor imaging

    NARCIS (Netherlands)

    Irwan, R; Sijens, PE; Potze, JH; Oudkerk, M

    2005-01-01

    Proton magnetic resonance spectroscopy (H-1-MRS) provides indices of neuronal damage. Diffusion tensor imaging (DTI) relates to water diffusivity and fiber tract orientation. A method to compare H-1-MRS and DTI findings was developed, tested on phantom and applied on normal brain. Point-resolved spe

  19. Diffusion-weighted imaging predicts cognition in pediatric brain injury.

    Science.gov (United States)

    Babikian, Talin; Tong, Karen A; Galloway, Nicholas R; Freier-Randall, Mary-Catherin; Obenaus, André; Ashwal, Stephen

    2009-12-01

    Apparent diffusion coefficient maps from diffusion-weighted imaging predict gross neurologic outcome in adults with traumatic brain injury. Few studies in children have been reported, and none have used apparent diffusion coefficient maps to predict long-term (>1 year) neurocognitive outcomes. In this study, pooled regional and total brain diffusion coefficients were used to predict long-term outcomes in 17 pediatric brain injury patients. Apparent diffusion coefficient values were grouped into peripheral and deep gray and white matter, posterior fossa, and total brain. Regions of interest excluded areas that appeared abnormal on T(2)-weighted images. Apparent diffusion coefficient values from peripheral regions were inversely correlated with cognitive functioning. No significant correlations were apparent between the cognitive scores and apparent diffusion coefficient values for deep tissue or the posterior fossa. Regression analyses suggested that combined peripheral gray and white matter apparent diffusion coefficients explained 42% of the variance in the combined neurocognitive index. Peripheral gray diffusion coefficients alone explained an additional 20% of variance after accounting for clinical variables. These results suggest that obtaining apparent diffusion coefficient values, specifically from peripheral brain regions, may predict long-term outcome after pediatric brain injury. Discrepancies in the literature on this topic, as well as possible explanations, including sampling and clinical considerations, are discussed.

  20. Diffusion-weighted imaging changes in cerebral watershed distribution following neonatal encephalopathy are not invariably associated with an adverse outcome

    NARCIS (Netherlands)

    Harteman, Johanna C.; Groenendaal, Floris; Toet, Mona C.; Benders, Manon J. N. L.; Van Haastert, Ingrid C.; Nievelstein, Rutger A. J.; Koopman-Esseboom, Corine; De Vries, Linda S.

    2013-01-01

    Aim Patterns of injury in term-born infants with neonatal encephalopathy following hypoxia-ischaemia are seen earlier and are more conspicuous on diffusion-weighted magnetic resonance imaging (DW-MRI) than on conventional imaging. Although the prognostic value of DW-MRI in infants with basal ganglia

  1. Fluid Registration of Diffusion Tensor Images Using Information Theory

    Science.gov (United States)

    Chiang, Ming-Chang; Leow, Alex D.; Klunder, Andrea D.; Dutton, Rebecca A.; Barysheva, Marina; Rose, Stephen E.; McMahon, Katie L.; de Zubicaray, Greig I.; Toga, Arthur W.; Thompson, Paul M.

    2008-01-01

    We apply an information-theoretic cost metric, the symmetrized Kullback-Leibler (sKL) divergence, or J-divergence, to fluid registration of diffusion tensor images. The difference between diffusion tensors is quantified based on the sKL-divergence of their associated probability density functions (PDFs). Three-dimensional DTI data from 34 subjects were fluidly registered to an optimized target image. To allow large image deformations but preserve image topology, we regularized the flow with a large-deformation diffeomorphic mapping based on the kinematics of a Navier-Stokes fluid. A driving force was developed to minimize the J-divergence between the deforming source and target diffusion functions, while reorienting the flowing tensors to preserve fiber topography. In initial experiments, we showed that the sKL-divergence based on full diffusion PDFs is adaptable to higher-order diffusion models, such as high angular resolution diffusion imaging (HARDI). The sKL-divergence was sensitive to subtle differences between two diffusivity profiles, showing promise for nonlinear registration applications and multisubject statistical analysis of HARDI data. PMID:18390342

  2. Denoising human cardiac diffusion tensor magnetic resonance images using sparse representation combined with segmentation

    Energy Technology Data Exchange (ETDEWEB)

    Bao, L J; Zhu, Y M; Liu, W Y; Pu, Z B; Magnin, I E [HIT-INSA Sino French Research Centre for Biomedical Imaging, Harbin Institute of Technology, Harbin (China); Croisille, P; Robini, M [CREATIS-LRMN, CNRS UMR 5220, Inserm U630, INSA of Lyon, University of Lyon 1, Villeurbanne (France)], E-mail: baolij@gmail.com

    2009-03-21

    Cardiac diffusion tensor magnetic resonance imaging (DT-MRI) is noise sensitive, and the noise can induce numerous systematic errors in subsequent parameter calculations. This paper proposes a sparse representation-based method for denoising cardiac DT-MRI images. The method first generates a dictionary of multiple bases according to the features of the observed image. A segmentation algorithm based on nonstationary degree detector is then introduced to make the selection of atoms in the dictionary adapted to the image's features. The denoising is achieved by gradually approximating the underlying image using the atoms selected from the generated dictionary. The results on both simulated image and real cardiac DT-MRI images from ex vivo human hearts show that the proposed denoising method performs better than conventional denoising techniques by preserving image contrast and fine structures.

  3. Malignant biliary stenosis: conventional cytology versus DNA image cytometry.

    Science.gov (United States)

    Binek, Janek; Lindenmann, Nadja; Meyenberger, Christa M; Hell, Margarete; Ulmer, Hanno; Spieler, Peter; Borovicka, Jan

    2011-06-01

    The aim of this study is to evaluate the utility of image cytometry (ICM)-DNA analysis on cytological brush specimens in improving the sensitivity and diagnostic accuracy for biliary neoplasias. A total of 71 patients with 89 samples of biliary tree brushing from a stenosis were included in this prospective study. Conventional cytology (CC) and DNA ploidy using ICM of the brushing were performed. Benign or malignant findings were confirmed by surgical exploration or a clinical follow-up of at least 12 months. Diagnosis was confirmed by clinical follow-up in 44 cases and surgical investigation or histology in 41 cases. A definitive diagnosis of the smears resulted in 40 malignant and 49 benign diagnoses. The sensitivity was 0.666 for CC and 0.658 for ICM, and the specificity was 0.920 and 0.937, respectively. The positive predictive value (PPV) was 0.866 for CC and 0.900 for ICM. McNemar's test did not reveal a significant difference between CC and ICM (P=0.803). Agreement of the two methods was found in 73 samples, raising specificity to 0.998 but not sensitivity (0.725). ICM-DNA seems not to improve significantly the PPV and NPV for detecting neoplasias of the biliary tract compared to CC. Nevertheless a clinical advantage can be seen in the agreement of the two methods in diagnosing dysplasia or cancer, since it did not show false positive results.

  4. Successful serial imaging of the mouse cerebral arteries using conventional 3-T magnetic resonance imaging

    Science.gov (United States)

    Makino, Hiroshi; Hokamura, Kazuya; Natsume, Takahiro; Kimura, Tetsuro; Kamio, Yoshinobu; Magata, Yasuhiro; Namba, Hiroki; Katoh, Takasumi; Sato, Shigehito; Hashimoto, Tomoki; Umemura, Kazuo

    2015-01-01

    Serial imaging studies can be useful in characterizing the pathologic and physiologic remodeling of cerebral arteries in various mouse models. We tested the feasibility of using a readily available, conventional 3-T magnetic resonance imaging (MRI) to serially image cerebrovascular remodeling in mice. We utilized a mouse model of intracranial aneurysm as a mouse model of the dynamic, pathologic remodeling of cerebral arteries. Aneurysms were induced by hypertension and a single elastase injection into the cerebrospinal fluid. For the mouse cerebrovascular imaging, we used a conventional 3-T MRI system and a 40-mm saddle coil. We used non-enhanced magnetic resonance angiography (MRA) to detect intracranial aneurysm formation and T2-weighted imaging to detect aneurysmal subarachnoid hemorrhage. A serial MRI was conducted every 2 to 3 days. MRI detection of aneurysm formation and subarachnoid hemorrhage was compared against the postmortem inspection of the brain that was perfused with dye. The imaging times for the MRA and T2-weighted imaging were 3.7±0.5 minutes and 4.8±0.0 minutes, respectively. All aneurysms and subarachnoid hemorrhages were correctly identified by two masked observers on MRI. This MRI-based serial imaging technique was useful in detecting intracranial aneurysm formation and subarachnoid hemorrhage in mice. PMID:25920958

  5. Effect of probe diffusion on the SOFI imaging accuracy

    Science.gov (United States)

    Vandenberg, Wim; Dedecker, Peter

    2017-01-01

    Live-cell super-resolution fluorescence imaging is becoming commonplace for exploring biological systems, though sample dynamics can affect the imaging quality. In this work we evaluate the effect of probe diffusion on super-resolution optical fluctuation imaging (SOFI), using a theoretical model and numerical simulations based on the imaging of live cells labelled with photochromic fluorescent proteins. We find that, over a range of physiological conditions, fluorophore diffusion results in a change in the amplitude of the SOFI signal. The magnitude of this change is approximately proportional to the on-time ratio of the fluorophores. However, for photochromic fluorescent proteins this effect is unlikely to present a significant distortion in practical experiments in biological systems. Due to this lack of distortions, probe diffusion strongly enhances the SOFI imaging by avoiding spatial undersampling caused by the limited labeling density. PMID:28333166

  6. Syphilitic myelitis with diffuse spinal cord abnormality on MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Tsui, E.Y.K.; Lai, K.F.; Chan, J.H.M. [Department of Radiology, Tuen Mun Hospital, Tuen Mun (Hong Kong); Ng, S.H.; Chow, L. [Department of Medicine, Tuen Mun Hospital, Tuen Mun (Hong Kong); Fong, D. [Department of Neurosurgery, Tuen Mun Hospital, Tuen Mun (Hong Kong)

    2002-12-01

    Syphilitic myelitis is a very rare manifestation of neurosyphilis. The MRI appearance of syphilitic myelitis is not well documented and only a few cases have been reported. We present a 52-year-old woman with acute onset of paraplegia. Magnetic resonance imaging of the spine showed diffuse high signal intensity in the whole spinal cord on T2-weighted images. Focal enhancement was observed in the dorsal aspect of the thoracic cord on T1-weighted gadolinium-enhanced images. To our knowledge, diffuse spinal cord abnormality in syphilitic myelitis has not been reported in the international literature. Disappearance of the diffuse high-signal lesions with residual focal enhancement was noted after antibiotic therapy. The patient suffered significant neurological deficit despite improvement in the MR images. In this article we present the imaging findings and review the literature of this rare condition. (orig.)

  7. Reduction of Diffusion-Weighted Imaging Contrast of Acute Ischemic Stroke at Short Diffusion Times.

    Science.gov (United States)

    Baron, Corey Allan; Kate, Mahesh; Gioia, Laura; Butcher, Kenneth; Emery, Derek; Budde, Matthew; Beaulieu, Christian

    2015-08-01

    Diffusion-weighted imaging (DWI) of tissue water is a sensitive and specific indicator of acute brain ischemia, where reductions of the diffusion of tissue water are observed acutely in the stroke lesion core. Although these diffusion changes have been long attributed to cell swelling, the precise nature of the biophysical mechanisms remains uncertain. The potential cause of diffusion reductions after stroke was investigated using an advanced DWI technique, oscillating gradient spin-echo DWI, that enables much shorter diffusion times and can improve specificity for alterations of structure at the micron level. Diffusion measurements in the white matter lesions of patients with acute ischemic stroke were reduced by only 8% using oscillating gradient spin-echo DWI, in contrast to a 37% decrease using standard DWI. Neurite beading has recently been proposed as a mechanism for the diffusion changes after ischemic stroke with some ex vivo evidence. To explore whether beading could cause such differential results, simulations of beaded cylinders and axonal swelling were performed, yielding good agreement with experiment. Short diffusion times result in dramatically reduced diffusion contrast of human stroke. Simulations implicate a combination of neuronal beading and axonal swelling as the key structural changes leading to the reduced apparent diffusion coefficient after stroke. © 2015 American Heart Association, Inc.

  8. Fast imaging of mean, axial and radial diffusion kurtosis

    DEFF Research Database (Denmark)

    Hansen, Brian; Shemesh, Noam; Jespersen, Sune Nørhøj

    2016-01-01

    Abstract Diffusion kurtosis imaging (DKI) is being increasingly reported to provide sensitive biomarkers of subtle changes in tissue microstructure. However, DKI also imposes larger data requirements than diffusion tensor imaging (DTI), hence, the widespread adaptation and exploration of DKI would...... for the first time, and referred to as axially symmetric DKI. The second approach is applicable in tissues with a priori known principal diffusion direction, and does not require fitting of any kind. The approaches are evaluated in human brain in vivo as well as in fixed rat spinal cord, and are demonstrated...... benefit from more efficient acquisition and computational methods. To meet this demand, we recently developed a method capable of estimating mean kurtosis with only 13 diffusion weighted images. This approach was later shown to provide very accurate mean kurtosis estimates and to be more efficient...

  9. Familial Mediterranean fever mimicking septic arthritis: distinguishing with diffusion weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Oner, Ali Yusuf; Ucar, Murat; Akpek, Sergin; Tokgoz, Nil [Gazi University School of Medicine, Department of Radiology, Besevler-Ankara (Turkey)

    2007-06-15

    FMF arthritis is generally monoarticular in origin. The affected joint is hot, tender, red and mimics septic arthritis. Conventional imaging findings, including magnetic resonance imaging (MRI) and ultrasound, do not help differentiate between these two entities. The final diagnosis depends on culture of the synovial fluid, and therefore initiation of proper drug therapy can be delayed. Diffusion weighted imaging (DWI), with its ability to detect altered water-proton mobility, might play an important role as a fast and non-invasive problem-solving tool in this setting. We here present MRI and DWI findings of a case of FMF arthritis mimicking septic arthritis. (orig.)

  10. Using quantum filters to process images of diffuse axonal injury

    Science.gov (United States)

    Pineda Osorio, Mateo

    2014-06-01

    Some images corresponding to a diffuse axonal injury (DAI) are processed using several quantum filters such as Hermite Weibull and Morse. Diffuse axonal injury is a particular, common and severe case of traumatic brain injury (TBI). DAI involves global damage on microscopic scale of brain tissue and causes serious neurologic abnormalities. New imaging techniques provide excellent images showing cellular damages related to DAI. Said images can be processed with quantum filters, which accomplish high resolutions of dendritic and axonal structures both in normal and pathological state. Using the Laplacian operators from the new quantum filters, excellent edge detectors for neurofiber resolution are obtained. Image quantum processing of DAI images is made using computer algebra, specifically Maple. Quantum filter plugins construction is proposed as a future research line, which can incorporated to the ImageJ software package, making its use simpler for medical personnel.

  11. Echo planar diffusion-weighted imaging: possibilities and considerations with 12- and 32-channel head coils.

    Science.gov (United States)

    Morelli, John N; Saettele, Megan R; Rangaswamy, Rajesh A; Vu, Lan; Gerdes, Clint M; Zhang, Wei; Ai, Fei

    2012-01-01

    Interest in clinical brain magnetic resonance imaging using 32-channel head coils for signal reception continues to increase. The present investigation assesses possibilities for improving diffusion-weighted image quality using a 32-channel in comparison to a conventional 12-channel coil. The utility of single-shot (ss) and an approach to readout-segmented (rs) echo planar imaging (EPI) are examined using both head coils. Substantial image quality improvements are found with rs-EPI. Imaging with a 32-channel head coil allows for implementation of greater parallel imaging acceleration factors or acquisition of scans at a higher resolution. Specifically, higher resolution imaging with rs-EPI can be achieved by increasing the number of readout segments without increasing echo-spacing or echo time to the degree necessary with ss-EPI - a factor resulting in increased susceptibility artifact and reduced signal-to-noise with the latter.

  12. Echo Planar Diffusion-Weighted Imaging: Possibilities and Considerations with 12- and 32-Channel Head Coils

    Directory of Open Access Journals (Sweden)

    John N Morelli

    2012-01-01

    Full Text Available Interest in clinical brain magnetic resonance imaging using 32-channel head coils for signal reception continues to increase. The present investigation assesses possibilities for improving diffusion-weighted image quality using a 32-channel in comparison to a conventional 12-channel coil. The utility of single-shot (ss and an approach to readout-segmented (rs echo planar imaging (EPI are examined using both head coils. Substantial image quality improvements are found with rs-EPI. Imaging with a 32-channel head coil allows for implementation of greater parallel imaging acceleration factors or acquisition of scans at a higher resolution. Specifically, higher resolution imaging with rs-EPI can be achieved by increasing the number of readout segments without increasing echo-spacing or echo time to the degree necessary with ss-EPI - a factor resulting in increased susceptibility artifact and reduced signal-to-noise with the latter.

  13. Image encryption using a synchronous permutation-diffusion technique

    Science.gov (United States)

    Enayatifar, Rasul; Abdullah, Abdul Hanan; Isnin, Ismail Fauzi; Altameem, Ayman; Lee, Malrey

    2017-03-01

    In the past decade, the interest on digital images security has been increased among scientists. A synchronous permutation and diffusion technique is designed in order to protect gray-level image content while sending it through internet. To implement the proposed method, two-dimensional plain-image is converted to one dimension. Afterward, in order to reduce the sending process time, permutation and diffusion steps for any pixel are performed in the same time. The permutation step uses chaotic map and deoxyribonucleic acid (DNA) to permute a pixel, while diffusion employs DNA sequence and DNA operator to encrypt the pixel. Experimental results and extensive security analyses have been conducted to demonstrate the feasibility and validity of this proposed image encryption method.

  14. Microcirculation assessment using an individualized model for diffuse reflectance spectroscopy and conventional laser Doppler flowmetry

    Science.gov (United States)

    Strömberg, Tomas; Karlsson, Hanna; Fredriksson, Ingemar; Nyström, Fredrik H.; Larsson, Marcus

    2014-05-01

    Microvascular assessment would benefit from co-registration of blood flow and hemoglobin oxygenation dynamics during stimulus response tests. We used a fiber-optic probe for simultaneous recording of white light diffuse reflectance (DRS; 475-850 nm) and laser Doppler flowmetry (LDF; 780 nm) spectra at two source-detector distances (0.4 and 1.2 mm). An inverse Monte Carlo algorithm, based on a multiparameter three-layer adaptive skin model, was used for analyzing DRS data. LDF spectra were conventionally processed for perfusion. The system was evaluated on volar forearm recordings of 33 healthy subjects during a 5-min systolic occlusion protocol. The calibration scheme and the optimal adaptive skin model fitted DRS spectra at both distances within 10%. During occlusion, perfusion decreased within 5 s while oxygenation decreased slowly (mean time constant 61 s dissociation of oxygen from hemoglobin). After occlusion release, perfusion and oxygenation increased within 3 s (inflow of oxygenized blood). The increased perfusion was due to increased blood tissue fraction and speed. The supranormal hemoglobin oxygenation indicates a blood flow in excess of metabolic demands. In conclusion, by integrating DRS and LDF in a fiber-optic probe, a powerful tool for assessment of blood flow and oxygenation in the same microvascular bed has been presented.

  15. Magnetic resonance diffusion tensor imaging-based evaluation of optic-radiation shape and position in meningioma.

    Science.gov (United States)

    Lv, Xueming; Chen, Xiaolei; Xu, Bainan; Zhang, Jiashu; Zheng, Gang; Li, Jinjiang; Li, Fangye; Sun, Guochen

    2012-03-25

    Employing magnetic resonance diffusion tensor imaging, three-dimensional white-matter imaging and conventional magnetic resonance imaging can demonstrate the tumor parenchyma, peritumoral edema and compression on surrounding brain tissue. A color-coded tensor map and three-dimensional tracer diagram were applied to clearly display the optic-radiation location, course and damage. Results showed that the altered anisotropy values of meningioma patients corresponded with optic-radiation shape, size and position on both sides. Experimental findings indicate that the magnetic resonance diffusion tensor imaging technique is a means of tracing and clearly visualizing the optic radiation.

  16. Magnetic resonance diffusion tensor imaging-based evaluation of optic-radiation shape and position in meningioma

    Institute of Scientific and Technical Information of China (English)

    Xueming Lv; Xiaolei Chen; Bainan Xu; Gang Zheng; Jinjiang Li; Fangye Li; Guochen Sun; liusan

    2012-01-01

    Employing magnetic resonance diffusion tensor imaging, three-dimensional white-matter imaging and conventional magnetic resonance imaging can demonstrate the tumor parenchyma, peritumoral edema and compression on surrounding brain tissue. A color-coded tensor map and three-dimensional tracer diagram were applied to clearly display the optic-radiation location, course and damage. Results showed that the altered anisotropy values of meningioma patients corresponded with optic-radiation shape, size and position on both sides. Experimental findings indicate that the magnetic resonance diffusion tensor imaging technique is a means of tracing and clearly visualizing the optic radiation.

  17. Diffusion-weighted imaging in acute demyelinating myelopathy

    Energy Technology Data Exchange (ETDEWEB)

    Zecca, Chiara; Cereda, Carlo; Tschuor, Silvia; Staedler, Claudio; Nadarajah, Navarajah; Bassetti, Claudio L.; Gobbi, Claudio [Ospedale Regionale di Lugano, Servizio di Neurologia e Neuroradiologia, Neurocenter of Southern Switzerland, Lugano (Switzerland); Wetzel, Stephan [Swiss Neuro Institute (SNI), Abteilung fuer Neuroradiologie, Hirslanden Klinik Zuerich, Zuerich (Switzerland); Santini, Francesco [University of Basel Hospital, Division of Radiological Physics, Basel (Switzerland)

    2012-06-15

    Diffusion-weighted imaging (DWI) has become a reference MRI technique for the evaluation of neurological disorders. Few publications have investigated the application of DWI for inflammatory demyelinating lesions. The purpose of the study was to describe diffusion-weighted imaging characteristics of acute, spinal demyelinating lesions. Six consecutive patients (two males, four females; aged 28-64 years) with acute spinal cord demyelinating lesions were studied in a prospective case series design from June 2009 to October 2010. We performed magnetic resonance imaging studies from 2 to 14 days from symptom onset on the patients with relapsing remitting multiple sclerosis (n = 3) or clinically isolated syndrome (n = 3). Main outcome measures were diffusion-weighted imaging and apparent diffusion coefficient pattern (ADC) of acute spinal cord demyelinating lesions. All spinal lesions showed a restricted diffusion pattern (DWI+/ADC-) with a 24% median ADC signal decrease. A good correlation between clinical presentation and lesion site was observed. Acute demyelinating spinal cord lesions show a uniform restricted diffusion pattern. Clinicians and neuro-radiologists should be aware that this pattern is not necessarily confirmatory for an ischaemic aetiology. (orig.)

  18. Whole-body diffusion imaging applying simultaneous multi-slice excitation

    Energy Technology Data Exchange (ETDEWEB)

    Kenkel, David; Wurning, M.C.; Filli, L.; Ulbrich, E.J.; Boss, A. [Universitaetsspital Zuerich (Switzerland). Diagnostische und Interventionelle Radiologie; Runge, V.M. [Univ. Hospital Zurich (Switzerland). Dept. of Neuroradiology; Beck, T. [Siemens Healthcare GmbH, Erlangen (Germany)

    2016-04-15

    The purpose of this study was to examine the feasibility of a fast protocol for whole-body diffusion-weighted imaging (WB-DWI) using a slice-accelerated echo-planar sequence, which, when using comparable image acquisition parameters, noticeably reduces measurement time compared to a conventional WB-DWI protocol. A single-shot echo-planar imaging sequence capable of simultaneous slice excitation and acquisition was optimized for WB-DWI on a 3 T MR scanner, with a comparable conventional WB-DWI protocol serving as the reference standard. Eight healthy individuals and one oncologic patient underwent WB-DWI. Quantitative analysis was carried out by measuring the apparent diffusion coefficient (ADC) and its coefficient of variation (CV) in different organs. Image quality was assessed qualitatively by two independent radiologists using a 4-point Likert scale. Using our proposed protocol, the scan time of the WB-DWI measurement was reduced by up to 25.9 %. Both protocols, the slice-accelerated protocol and the conventional protocol, showed comparable image quality without statistically significant differences in the reader scores. Similarly, no significant differences of the ADC values of parenchymal organs were found, whereas ADC values of brain tissue were slightly higher in the slice-accelerated protocol. It was demonstrated that slice-accelerated DWI can be applied to WB-DWI protocols with the potential to greatly reduce the required measurement time, thereby substantially increasing clinical applicability.

  19. Diffusion weighted imaging in cystic fibrosis disease: beyond morphological imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ciet, Pierluigi [Erasmus Medical Center, Department of Radiology, Rotterdam (Netherlands); Erasmus Medical Center - Sophia Children' s Hospital, Department of Paediatrics, Respiratory Medicine and Allergology, P.O. Box 2060, Rotterdam, Zuid-Holland (Netherlands); Ca' Foncello - General Hospital, Department of Radiology, Treviso (Italy); Serra, Goffredo; Catalano, Carlo [University of Rome ' ' Sapienza' ' , Department of Radiology, Rome (Italy); Andrinopoulou, Eleni Rosalina [Erasmus Medical Center, Department of Biostatistics, Rotterdam (Netherlands); Bertolo, Silvia; Morana, Giovanni [Ca' Foncello - General Hospital, Department of Radiology, Treviso (Italy); Ros, Mirco [Ca' Foncello Hospital, Department of Pediatrics, Treviso (Italy); Colagrande, Stefano [University of Florence - Azienda Ospedaliero-Universitaria Careggi, Department of Experimental and Clinical Biomedical Sciences, Radiodiagnostic Unit n. 2, Florence (Italy); Tiddens, Harm A.W.M. [Erasmus Medical Center, Department of Radiology, Rotterdam (Netherlands); Erasmus Medical Center - Sophia Children' s Hospital, Department of Paediatrics, Respiratory Medicine and Allergology, P.O. Box 2060, Rotterdam, Zuid-Holland (Netherlands)

    2016-11-15

    To explore the feasibility of diffusion-weighted imaging (DWI) to assess inflammatory lung changes in patients with Cystic Fibrosis (CF) CF patients referred for their annual check-up had spirometry, chest-CT and MRI on the same day. MRI was performed in a 1.5 T scanner with BLADE and EPI-DWI sequences (b = 0-600 s/mm{sup 2}). End-inspiratory and end-expiratory scans were acquired in multi-row scanners. DWI was scored with an established semi-quantitative scoring system. DWI score was correlated to CT sub-scores for bronchiectasis (CF-CT{sub BE}), mucus (CF-CT{sub mucus}), total score (CF-CT{sub total-score}), FEV{sub 1}, and BMI. T-test was used to assess differences between patients with and without DWI-hotspots. Thirty-three CF patients were enrolled (mean 21 years, range 6-51, 19 female). 4 % (SD 2.6, range 1.5-12.9) of total CF-CT alterations presented DWI-hotspots. DWI-hotspots coincided with mucus plugging (60 %), consolidation (30 %) and bronchiectasis (10 %). DWI{sub total-score} correlated (all p < 0.0001) positively to CF-CT{sub BE} (r = 0.757), CF-CT{sub mucus} (r = 0.759) and CF-CT{sub total-score} (r = 0.79); and negatively to FEV{sub 1} (r = 0.688). FEV{sub 1} was significantly higher (p < 0.0001) in patients without DWI-hotspots. DWI-hotspots strongly correlated with radiological and clinical parameters of lung disease severity. Future validation studies are needed to establish the exact nature of DWI-hotspots in CF patients. (orig.)

  20. Anthropomorphic image reconstruction via hypoelliptic diffusion

    CERN Document Server

    Boscain, Ugo; Gauthier, Jean-Paul; Rossi, Francesco

    2010-01-01

    In this paper we present a model of geometry of vision which generalizes one due to Petitot, Citti and Sarti. One of its main features is that the primary visual cortex V1 lifts the image from $R^2$ to the bundle of directions of the plane $PTR^2=R^2\\times P^1$. Neurons are grouped into orientation columns, each of them corresponding to a point of the bundle $PTR^2$. In this model a corrupted image is reconstructed by minimizing the energy necessary for the activation of the orientation columns corresponding to regions in which the image is corrupted. The minimization process gives rise to an hypoelliptic heat equation on $PTR^2$. The hypoelliptic heat equation is studied using the generalized Fourier transform. It transforms the hypoelliptic equation into a 1-d heat equation with Mathieu potential, which one can solve numerically. Preliminary examples of image reconstruction are hereby provided.

  1. Hypofractionation vs Conventional Radiation Therapy for Newly Diagnosed Diffuse Intrinsic Pontine Glioma: A Matched-Cohort Analysis

    NARCIS (Netherlands)

    Janssens, G.O.R.J.; Jansen, M.H.; Lauwers, S.J.; Nowak, P.J.; Oldenburger, F.R.; Bouffet, E.; Saran, F.; Kamphuis-van Ulzen, K.; Lindert, E.J. van; Schieving, J.H.; Boterberg, T.; Kaspers, G.J.L.; Span, P.N.; Kaanders, J.H.A.M.; Gidding, C.E.M.; Hargrave, D.

    2013-01-01

    PURPOSE: Despite conventional radiation therapy, 54 Gy in single doses of 1.8 Gy (54/1.8 Gy) over 6 weeks, most children with diffuse intrinsic pontine glioma (DIPG) will die within 1 year after diagnosis. To reduce patient burden, we investigated the role of hypofractionation radiation therapy give

  2. A volume scanner for diffuse imaging

    Science.gov (United States)

    Vafa, Elham; Roberts, Nicolas; Sharafutdinova, Galiya; Holdsworth, John

    2016-11-01

    Non-invasive optical screening mammography has a significant barrier in the extreme scatter of human tissue at optical wavelengths. A volume scanner suited for high numerical aperture capture of scattered light from diffuse media has been designed, modelled using Trace Pro software and experimentally constructed. Modelling results indicate the presence of an embedded volume with different scatter properties from the bulk yields a measurable difference in the overall scatter pattern and intensity recorded. Work towards a full tomographic reconstruction from scattered light recorded on the two dimensional array detector is currently underway.

  3. The effects of transducer geometry on artifacts common to diagnostic bone imaging with conventional medical ultrasound.

    Science.gov (United States)

    Mauldin, F William; Owen, Kevin; Tiouririne, Mohamed; Hossack, John A

    2012-06-01

    The portability, low cost, and non-ionizing radiation associated with medical ultrasound suggest that it has potential as a superior alternative to X-ray for bone imaging. However, when conventional ultrasound imaging systems are used for bone imaging, clinical acceptance is frequently limited by artifacts derived from reflections occurring away from the main axis of the acoustic beam. In this paper, the physical source of off-axis artifacts and the effect of transducer geometry on these artifacts are investigated in simulation and experimental studies. In agreement with diffraction theory, the sampled linear-array geometry possessed increased off-axis energy compared with single-element piston geometry, and therefore, exhibited greater levels of artifact signal. Simulation and experimental results demonstrated that the linear-array geometry exhibited increased artifact signal when the center frequency increased, when energy off-axis to the main acoustic beam (i.e., grating lobes) was perpendicularly incident upon off-axis surfaces, and when off-axis surfaces were specular rather than diffusive. The simulation model used to simulate specular reflections was validated experimentally and a correlation coefficient of 0.97 between experimental and simulated peak reflection contrast was observed. In ex vivo experiments, the piston geometry yielded 4 and 6.2 dB average contrast improvement compared with the linear array when imaging the spinous process and interlaminar space of an animal spine, respectively. This work indicates that off-axis reflections are a major source of ultrasound image artifacts, particularly in environments comprising specular reflecting (i.e., bone or bone-like) objects. Transducer geometries with reduced sensitivity to off-axis surface reflections, such as a piston transducer geometry, yield significant reductions in image artifact.

  4. Updates in advanced diffusion-weighted magnetic resonance imaging techniques in the evaluation of prostate cancer

    Institute of Scientific and Technical Information of China (English)

    Hebert; Alberto; Vargas; Edward; Malnor; Lawrence; Yousef; Mazaheri; Evis; Sala

    2015-01-01

    Diffusion-weighted magnetic resonance imaging(DWMRI) is considered part of the standard imaging protocol for the evaluation of patients with prostate cancer.It has been proven valuable as a functional tool for qualitative and quantitative analysis of prostate cancer beyond anatomical MRI sequences such as T2-weighted imaging. This review discusses ongoing controversies in DW-MRI acquisition, including the optimal number of b-values to be used for prostate DWI, and summarizes the current literature on the use of advanced DWMRI techniques. These include intravoxel incoherent motion imaging, which better accounts for the nonmono-exponential behavior of the apparent diffusion coefficient as a function of b-value and the influence of perfusion at low b-values. Another technique is diffusion kurtosis imaging(DKI). Metrics from DKI reflect excess kurtosis of tissues, representing its deviation from Gaussian diffusion behavior. Preliminary results suggest that DKI findings may have more value than findings from conventional DW-MRI for the assessment of prostate cancer.

  5. Langevin equation approach to diffusion magnetic resonance imaging.

    Science.gov (United States)

    Cooke, Jennie M; Kalmykov, Yuri P; Coffey, William T; Kerskens, Christian M

    2009-12-01

    The normal phase diffusion problem in magnetic resonance imaging (MRI) is treated by means of the Langevin equation for the phase variable using only the properties of the characteristic function of Gaussian random variables. The calculation may be simply extended to anomalous diffusion using a fractional generalization of the Langevin equation proposed by Lutz [E. Lutz, Phys. Rev. E 64, 051106 (2001)] pertaining to the fractional Brownian motion of a free particle coupled to a fractal heat bath. The results compare favorably with diffusion-weighted experiments acquired in human neuronal tissue using a 3 T MRI scanner.

  6. ORTHOGONAL-DIRECTIONAL FORWARD DIFFUSION IMAGE INPAINTING AND DENOISING MODEL

    Institute of Scientific and Technical Information of China (English)

    Wu Jiying; Ruan Qiuqi; An Gaoyun

    2008-01-01

    In this paper,an orthogonal-directional forward diffusion Partial Differential Equation (PDE) image inpainting and denoising model which processes image based on variation problem is proposed. The novel model restores the damaged information and smoothes the noise in image si-multaneously. The model is morphological invariant which processes image based on the geometrical property. The regularization item of it diffuses along and cross the isophote,and then the known image information is transported into the target region through two orthogonal directions. The cross isophote diffusion part is the TV (Total Variation) equation and the along isophote diffusion part is the inviscid Helmholtz vorticity equation. The equivalence between the Helmholtz equation and the inpainting PDEs is proved. The model with the fidelity item which is used in the whole image domain denoises while preserving edges. So the novel model could inpaint and denoise simultaneously. Both theoretical analysis and experiments have verified the validity of the novel model proposed in this paper.

  7. Identifying the limitations of conventional biofiltration of diffuse methane emissions at long-term operation.

    Science.gov (United States)

    Gómez-Cuervo, S; Hernández, J; Omil, F

    2016-08-01

    There is growing international concern about the increasing levels of greenhouse gases in the atmosphere, particularly CO2 and methane. The emissions of methane derived from human activities are associated with large flows and very low concentrations, such as those emitted from landfills and wastewater treatment plants, among others. The present work was focused on the biological methane degradation at diffuse concentrations (0.2% vv(-1)) in a conventional biofilter using a mixture of compost, perlite and bark chips as carrier. An extensive characterization of the process was carried out at long-term operation (250 days) in a fully monitored pilot plant, achieving stable conditions during the entire period. Operational parameters such as waterings, nitrogen addition and inlet loads and contact time influences were evaluated. Obtained results indicate that empty bed residence times within 4-8 min are crucial to maximize elimination rates. Waterings and the type of nitrogen supplied in the nutrient solution (ammonia or nitrate) have a strong impact on the biofilter performance. The better results compatible with a stable operation were achieved using nitrate, with elimination capacities up to 7.6 ± 1.1 g CH4 m(-3 )h(-1). The operation at low inlet concentrations (IC) implied that removal rates obtained were quite limited (ranging 3-8 g CH4 m(-3 )h(-1)); however, these results could be significantly increased (up to 20.6 g CH4 m(-3) h(-1)) at higher IC, which indicates that the mass transfer from the gas to the liquid layer surrounding the biofilm is a key limitation of the process.

  8. Diffusion tensor imaging of the human calf: Variation of inter- and intramuscle-specific diffusion parameters.

    Science.gov (United States)

    Schlaffke, Lara; Rehmann, Robert; Froeling, Martijn; Kley, Rudolf; Tegenthoff, Martin; Vorgerd, Matthias; Schmidt-Wilcke, Tobias

    2017-10-01

    To investigate to what extent inter- and intramuscular variations of diffusion parameters of human calf muscles can be explained by age, gender, muscle location, and body mass index (BMI) in a specific age group (20-35 years). Whole calf muscles of 18 healthy volunteers were evaluated. Magnetic resonance imaging (MRI) was performed using a 3T scanner and a 16-channel Torso XL coil. Diffusion-weighted images were acquired to perform fiber tractography and diffusion tensor imaging (DTI) analysis for each muscle of both legs. Fiber tractography was used to separate seven lower leg muscles. Associations between DTI parameters and confounds were evaluated. All muscles were additionally separated in seven identical segments along the z-axis to evaluate intramuscular differences in diffusion parameters. Fractional anisotropy (FA) and mean diffusivity (MD) were obtained for each muscle with low standard deviations (SDs) (SDFA : 0.01-0.02; SDMD : 0.07-0.14(10(-3) )). We found significant differences in FA values of the tibialis anterior muscle (AT) and extensor digitorum longus (EDL) muscles between men and women for whole muscle FA (two-sample t-tests; AT: P = 0.0014; EDL: P = 0.0004). We showed significant intramuscular differences in diffusion parameters between adjacent segments in most calf muscles (P muscle insertions showed higher (SD 0.03-0.06) than muscle bellies (SD 0.01-0.03), no relationships between FA or MD with age or BMI were found. Inter- and intramuscular variations in diffusion parameters of the calf were shown, which are not related to age or BMI in this age group. Differences between muscle belly and insertion should be considered when interpreting datasets not including whole muscles. 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1137-1148. © 2017 International Society for Magnetic Resonance in Medicine.

  9. Role of diffusion-weighted imaging in early ankylosing spondylitis

    Institute of Scientific and Technical Information of China (English)

    PAN Chu; HU Dao-yu; ZHANG Wei; LI Xiao-ming

    2013-01-01

    Background With the advanced MRI techniques,pathologic features can be detected at an early stage and quantitatively evaluated,resulting in the advantages of early diagnosis and prompt treatment.This study aimed to determine the value of diffusion-weighted MR imaging (DWl) in detection of early ankylosing spondylitis (AS) and investigate the characteristic manifestations of AS on whole body DWl (WB-DWl).Methods Twenty patients with the diagnosis of early AS,twenty patients with low back pain (LBP),and twenty-five healthy volunteers were included in this study.The subchondral bone apparent diffusion coefficients (ADC) among these groups in the bilateral ilia and sacrum along the sacroiliac joints were compared.An independent sample t-test was utilized to analyze ADC value differences among groups.P-values less than 0.05 denoted statistical significance.The mean ADC values of focal DWI lesions in AS patients were also measured.Whole body diffusion-weighted imaging was performed in fifteen additional AS patients,and analyzed with MIP and MPR techniques in comparison to conventional MR images in order to evaluate the ability to detect AS lesions with whole body DWI.Results Mean ADC values in AS patients were (0.518±0.122)x10-3 mm2/s in the ilium and (0.503±0.168)x10-3 mm2/s in the sacrum.These were significantly greater than the values measured in the ilium and sacrum of LBP patients,(0.328±0.053)x10-3 mm2/s in the ilium and (0.311±0.081)x10-3 m2/s in the sacrum,and control group,(0.325±0.015)x10-3 mm2/s in the ilium and (0.318±0.011)x10-3 mm2/s in the sacrum respectively.No statistically significant differences were found between LBP group and control group.The mean ADC value of focal DWI lesions in early AS patients was (0.899±0.265)x10-3 mm2/s,which was significantly higher than that of adjacent normal-appearance areas ((0.454±0.079)x103 mm2/s).WB-DWI detected abnormalities in the 15 additional AS patients both within the sacroiliac joints and at other sites

  10. Table-top diffuse optical imaging

    NARCIS (Netherlands)

    Sturgeon, K.A.; Bakker, L.P.

    2006-01-01

    This report describes the work done during a six months internshipat Philips Research for a Masters in Electronic and Electrical Engineering. An existing table-top tomography system for measuring lightin phantom breasts was restored. Updated software control and image reconstruction software was cr

  11. Table-top diffuse optical imaging

    NARCIS (Netherlands)

    Sturgeon, K.A.; Bakker, L.P.

    2006-01-01

    This report describes the work done during a six months internshipat Philips Research for a Masters in Electronic and Electrical Engineering. An existing table-top tomography system for measuring lightin phantom breasts was restored. Updated software control and image reconstruction software was cr

  12. GRADING OF RABBIT SKELETAL MUSCLE TRAUMA BY DIFFUSION TENSOR IMAGING AND TRACTOGRAPHY ON MAGNETIC RESONANCE IMAGING

    Institute of Scientific and Technical Information of China (English)

    Hui Zeng; Jun-hui Zheng; Jin-e Zhang; Yan-hui Liu; Shao-heng Tan; Guang-yi Wang; Chang-hong Liang

    2006-01-01

    Objective To distinguish the edema,injury,or rupture in the traumatic skeletal muscle fiber in vivo using diffusion tensor imaging (DTI) and tractography on magnetic resonance imaging (MRI).Methods The skeletal muscle trauma models were made in 4 rabbits (eight hindlimbs) by iron discus (weight 1.0 kg,diameter 6 cm) falling down vertically from 45 cm height to rabbits' thighs.Conventional sequences and two-dimensional (2D) diffusion-weighted (DW) spin-echo (SE) echo planar imaging (EPI) sequence with fat suppression (b=600 s/mm2) were performed on 1.5T MRI scanner.The grading of edema,injury,and fiber rupture in the damaged muscle were made according to their histopathological views,which was consistent with the images.The mean apparent diffusion coefficient (ADC) values and fractional anisotropy (FA) values were measured from the region of interests (ROIs) of all groups on 2D DW images used for tractography.Analysis of variance test was performed to analyze all data.Results ADC values of the areas in normal muscle,edema muscle,injury muscle,and ruptured muscle were (6.12±1.34)×10-3,(6.38±1.30)×10-3,(8.06±0.97)×10-3,and (9.57±0.93)×10-3 mm2/s,respectively.There was significant difference among groups (P<0.001),but no difference between edema muscle and normal muscle group (P>0.05).The FA values of normal muscle,edema muscle,injury muscle,and ruptured muscle were 0.42±0.12,0.36±0.12,0.26±0.09,0.12±0.08,respectively,with a significant difference among groups (P<0.001).In the edema muscle,the tracking cross-fiber could be seen but it decreased slightly.In the injury muscle,the tracking fiber decreased markedly.In the ruptured muscle,the transverse-orientation tracking fiber vanished,yet some interrupted longitudinal-orientation tracking fiber could be found.Conclusion The edema,injury,and rupture of muscle fiber in rabbit damaged skeletal muscle can be verified according to the ADC and the FA on DTI and tractography.

  13. Clinical applications of diffusion imaging in the spine.

    Science.gov (United States)

    Tanenbaum, Lawrence N

    2013-05-01

    As in the brain, the sensitivity of diffusion-weighted imaging (DWI) to ischemic damage in the spinal cord may provide early identification of infarction. Diffusion anisotropy may enhance the detection and understanding of damage to the long fiber tracts with clinical implications for diseases such as multiple sclerosis and amyotrophic lateral sclerosis and may also yield insight into damage that occurs with spondylotic and traumatic myelopathy. This article reviews the basis for DWI for the evaluation of the spinal cord, osseous, and soft tissues of the spine and reviews the imaging appearance of a variety of disease states.

  14. Diffusion MR Imaging of the Brain in Patients with Cancer

    Directory of Open Access Journals (Sweden)

    J. Matthew Debnam

    2011-01-01

    Full Text Available Over the last several years, there has been significant advancement in the molecular characterization of intracranial diseases, particularly cerebral neoplasms. While nuclear medicine technology, including PET/CT, has been at the foreground of exploration, new MR imaging techniques, specifically diffusion-weighted and diffusion tensor imaging, have shown interesting applications towards advancing our understanding of cancer involving the brain. In this paper, we review the fundamentals and basic physics of these techniques, and their applications to patient care for both general diagnostic use and in answering specific questions in selection of patients in terms of expected response to treatment.

  15. Application of Perona Malik anisotropic diffusion on digital radiographic image

    Energy Technology Data Exchange (ETDEWEB)

    Halim, Suhaila Abd; Razak, Rohayu Abdul; Ibrahim, Arsmah [Center of Mathematics Studies, Faculty of Computer and Mathematical Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor DE (Malaysia); Manurung, Yupiter HP [Advanced Manufacturing Technology Center, Faculty of Mechanical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor DE (Malaysia)

    2014-07-10

    Perona Malik Anisotropic Diffusion (PMAD) is a very useful and efficient denoising technique if the parameters are properly selected. Overestimating the parameters may cause oversmoothed and underestimating it may leave unfiltered noise. This makes the selection of parameters a crucial process. In this paper the PMAD model is solved using a finite difference scheme The discretized model is evaluated using different diffusion coefficient of exponential and quadratic on defective radiographic images in terms of quality and efficiency. In the application of the PMAD model on image data, a set of defective radiographic images of welding is used as input data. Peak Signal to Noise Ratio (PSNR), Structural Similarity Measure (SSIM) and temporal time are used to evaluate the performance of the model. The implementation of the experiment has been carried out using MATLAB R2009a. In terms of quality, results show that the Quadratic Diffusion Coefficient Function (QDCF) provides better results compared with the Exponential Diffusion Coefficient Function (EDCF). In conclusion, the denoising effect using PMAD model based on finite difference scheme shows able to improve image quality by removing noise in the defective radiographic image.

  16. Functional imaging of small tissue volumes with diffuse optical tomography

    Science.gov (United States)

    Klose, Alexander D.; Hielscher, Andreas H.

    2006-03-01

    Imaging of dynamic changes in blood parameters, functional brain imaging, and tumor imaging are the most advanced application areas of diffuse optical tomography (DOT). When dealing with the image reconstruction problem one is faced with the fact that near-infrared photons, unlike X-rays, are highly scattered when they traverse biological tissue. Image reconstruction schemes are required that model the light propagation inside biological tissue and predict measurements on the tissue surface. By iteratively changing the tissue-parameters until the predictions agree with the real measurements, a spatial distribution of optical properties inside the tissue is found. The optical properties can be related to the tissue oxygenation, inflammation, or to the fluorophore concentration of a biochemical marker. If the model of light propagation is inaccurate, the reconstruction process will lead to an inaccurate result as well. Here, we focus on difficulties that are encountered when DOT is employed for functional imaging of small tissue volumes, for example, in cancer studies involving small animals, or human finger joints for early diagnosis of rheumatoid arthritis. Most of the currently employed image reconstruction methods rely on the diffusion theory that is an approximation to the equation of radiative transfer. But, in the cases of small tissue volumes and tissues that contain low scattering regions diffusion theory has been shown to be of limited applicability Therefore, we employ a light propagation model that is based on the equation of radiative transfer, which promises to overcome the limitations.

  17. 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).

  18. Application of diffusion tensor imaging in neurosurgery; Anwendung der Diffusions-Tensor-Bildgebung in der Neurochirurgie

    Energy Technology Data Exchange (ETDEWEB)

    Saur, R. [Sektion fuer Experimentelle Kernspinresonanz des ZNS, Abt. Neuroradiologie, Universitaetsklinikum Tuebingen (Germany); Augenklinik des Universitaetsklinikums Tuebingen (Germany); Klinik fuer Psychiatrie und Psychotherapie des Universitaetsklinikums Tuebingen (Germany); Gharabaghi, A. [Klinik fuer Neurochirurgie des Universitaetsklinikums Tuebingen (Germany); Erb, M. [Sektion fuer Experimentelle Kernspinresonanz des ZNS, Abt. Neuroradiologie, Universitaetsklinikum Tuebingen (Germany)

    2007-07-01

    Knowledge about integrity and location of fibre tracts arising from eloquent cortical areas is important to plan neurosurgical interventions and to allow maximization of resection of pathological tissue while preserving vital white matter tracts. Diffusion Tensor Imaging (DTI) is so far the only method to get preoperatively an impression of the individual complexity of nerve bundles. Thereby nerve fibres are not mapped directly. They are derived indirectly by analysis of the directional distribution of diffusion of water molecules which is influenced mainly by large fibre tracts. From acquisition to reconstruction and visualisation of the fibre tracts many representational stages and working steps have to be passed. Exact knowledge about problems of Diffusion Imaging is important for interpretation of the results. Particularly, brain tumor edema, intraoperative brain shift, MR-artefacts and limitations of the mathematical models and algorithms challenge DTI-developers and applicants. (orig.)

  19. Coronal Diffusion-weighted Magnetic Resonance Imaging of the Kidney: Agreement with Axial Diffusion-weighted Magnetic Imaging in Terms of Apparent Diffusion Coefficient Values

    Institute of Scientific and Technical Information of China (English)

    Hai-Yi Wang; Jia Wang; Ye-Huan Tang; Hui-Yi Ye; Lin Ma

    2015-01-01

    Background:Coronal diffusion-weighted magnetic resonance imaging (DW-MRI) and apparent diffusion coefficient (ADC) values have gradually become applied (following conventional axial DW-MRI) in the renal analysis.To explore whether data obtained using coronal DW-MRI are comparable with those derived using axial DW-MRI,this preliminary study sought to assess the agreement in renal ADC values between coronal DW-MRI and axial DW-MRI.Methods:Thirty-four healthy volunteers were enrolled in the study; written consents were obtained.All subjects underwent respiratory-triggered axial and coronal DW-MRI using a 1.5-MR system with b values of 0 and 800 s/mm2.The signal-to-noise ratios (SNRs) of the two DW-MRI sequences were measured and statistically compared using the paired t-test.The extent of agreement of ADC values of the upper pole,mid-pole,and lower pole of the kidney; the mean ADC values of the left kidney and right kidney; and the mean ADC values of the bilateral kidneys were evaluated via calculation of intraclass correlation coefficients (ICCs) or Bland-Altman method between the two DW-MRI sequences.Results:The SNR of coronal DW-MR images was statistically inferior to that of axial DW-MR images (P < 0.001).The ICCs of the ADC values of each region of interest,and the mean ADC values of bilateral kidneys,between the two sequences,were greater than 0.5,and the mean ADCs of the bilateral kidneys demonstrated the highest ICC (0.869; 95% confidence interval:0.739-0.935).In addition,94.1% (32/34),94.1% (32/34),and 97.1% (31/34) of the ADC bias was inside the limits of agreement in terms of the mean ADC values of the left kidneys,right kidneys,and bilateral kidneys when coronal and axial DWI-MRI were compared.Conclusions:ADC values derived using coronal DW-MRI exhibited moderate-to-good agreement to those of axial DW-MRI,rendering the former an additional useful DW-MRI method,and causing the ADC values derived using the two types of DW-MRI to be comparable.

  20. Diffusion-weighted images of intracranial cyst-like lesions

    Energy Technology Data Exchange (ETDEWEB)

    Bergui, M.; Zhong, J.; Sales, S. [Dept. of Neuroradiology, University of Turin (Italy); Bradac, G.B. [Dept. of Neuroradiology, University of Turin (Italy); Neuroradiologia Universitaria, Ospedale S. G. Battista, Turin (Italy)

    2001-10-01

    Magnetic resonance sequences may be designed to evaluate the diffusion movements of the protons (diffusion-weighted images, DWI). In these images, a bright signal identifies a region where the diffusion along a spatial axis is restricted. The contents of a cystic lesion frequently have the signal intensities of a generic homogeneous hyperproteinic fluid (hypointensity in T1-, hyperintensity in T2-weighted images). DWI may give further information about the microscopic organisation of these fluids: a hyperintense signal indicates the presence of a restricted diffusion, due to some kind of microscopic organisation, at the cellular or macromolecular level. This may provide additional information useful for clinical purposes. We obtained DWI in 24 consecutive patients with intracranial cystic lesions, (19 intra-axial: five abscesses, five gliomas, six metastases, two demyelinating lesions, one neurocysticercosis; five extra-axial: two arachnoid cysts, two epidermoid cysts, one cholesteatoma). We found a strongly hyperintense signal, indicating restricted diffusion, in brain abscesses, epidermoid cysts and cholesteatoma; all the remaining lesions were hypointense or mildly hyperintense. We found these data useful in critical diagnoses, such as in differentiating abscesses from tumours, and in identifying elusive tumours such as epidermoid cysts. (orig.)

  1. Oriented diffusion filtering for enhancing low-quality fingerprint images

    KAUST Repository

    Gottschlich, C.

    2012-01-01

    To enhance low-quality fingerprint images, we present a novel method that first estimates the local orientation of the fingerprint ridge and valley flow and next performs oriented diffusion filtering, followed by a locally adaptive contrast enhancement step. By applying the authors\\' new approach to low-quality images of the FVC2004 fingerprint databases, the authors are able to show its competitiveness with other state-of-the-art enhancement methods for fingerprints like curved Gabor filtering. A major advantage of oriented diffusion filtering over those is its computational efficiency. Combining oriented diffusion filtering with curved Gabor filters led to additional improvements and, to the best of the authors\\' knowledge, the lowest equal error rates achieved so far using MINDTCT and BOZORTH3 on the FVC2004 databases. The recognition performance and the computational efficiency of the method suggest to include oriented diffusion filtering as a standard image enhancement add-on module for real-time fingerprint recognition systems. In order to facilitate the reproduction of these results, an implementation of the oriented diffusion filtering for Matlab and GNU Octave is made available for download. © 2012 The Institution of Engineering and Technology.

  2. Three dimensional reconstruction of conventional stereo optic disc image.

    Science.gov (United States)

    Kong, H J; Kim, S K; Seo, J M; Park, K H; Chung, H; Park, K S; Kim, H C

    2004-01-01

    Stereo disc photograph was analyzed and reconstructed as 3 dimensional contour image to evaluate the status of the optic nerve head for the early detection of glaucoma and the evaluation of the efficacy of treatment. Stepwise preprocessing was introduced to detect the edge of the optic nerve head and retinal vessels and reduce noises. Paired images were registered by power cepstrum method and zero-mean normalized cross-correlation. After Gaussian blurring, median filter application and disparity pair searching, depth information in the 3 dimensionally reconstructed image was calculated by the simple triangulation formula. Calculated depth maps were smoothed through cubic B-spline interpolation and retinal vessels were visualized more clearly by adding reference image. Resulted 3 dimensional contour image showed optic cups, retinal vessels and the notching of the neural rim of the optic disc clearly and intuitively, helping physicians in understanding and interpreting the stereo disc photograph.

  3. Diffuse large B-cell lymphoma in the era of precision oncology: How imaging is helpful

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Hina J.; Keraliya, Abhishek R.; Lele, Vikram R.; Tirumani, Sree Harsha; DiPiro, Pamela J.; Jagannathan, Jyothi P. [Dept. of Imaging, Dana Farber Cancer Institute, Harvard Medical School, Boston (United States)

    2017-01-15

    Diffuse large B cell lymphoma (DLBCL) is the most common histological subtype of Non-Hodgkin's lymphoma. As treatments continues to evolve, so do imaging strategies, and positron emission tomography (PET) has emerged as the most important imaging tool to guide oncologists in the diagnosis, staging, response assessment, relapse/recurrence detection,and therapeutic decision making of DLBCL. Other imaging modalities including magnetic resonance imaging (MRI), computed tomography (CT), ultrasound, and conventional radiography are also used in the evaluation of lymphoma. MRI is useful for nervous system and musculoskeletal system involvement and is emerging as a radiation free alternative to PET/CT. This article provides a comprehensive review of both the functional and morphological imaging modalities, available in the management of DLBCL.

  4. Super-resolution in brain Diffusion Weighted Imaging (DWI)

    OpenAIRE

    Tarquino González, Jonathan Steve

    2014-01-01

    Abstract. Diffusion Weighted (DW) imaging has proven to be useful at analysing brain architecture as well as at establishing brain tract organization and neuronal connectivity. However, an actual clinical use of DW images is currently limited by a series of acquisition artifacts, among them the partial volume effect (PVE) that may completely alter the spatial resolution and therefore the visualization of microanatomical details. In this work, a new superresolution method will be presented, ta...

  5. Comparison of conventional B-scan, tissue harmonic imaging, compound imaging and tissue harmonic compound imaging in neck lesion characterisation.

    Science.gov (United States)

    Bozzato, Alessandro; Loika, Anne; Hornung, Joachim; Koch, Michael; Zenk, Johannes; Uter, Wolfgang; Iro, Heinrich

    2010-10-01

    In recent years, further technical developments of ultrasound scanning techniques, such as tissue harmonic imaging (THI) and compound imaging (CI), have become available and promise considerable improvement in image quality. No comparative assessments have yet been made of their systematic use in the head and neck. We studied 313 lesions of the head and neck detected on ultrasound scanning. Ultrasound images were obtained using a state-of-the-art scanning system. Two experts evaluated the images obtained for each lesion with conventional B-scan mode (BSCAN), THI, CI, and tissue harmonic compound imaging (THICI) with respect to four different aspects of image quality. Largely concordant results were found for each of the parameters studied: overall image quality, tissue contrast, lesion conspicuity, and internal structure. Evaluations of CI and THICI were frequently ranked higher (p Images obtained in BSCAN mode often had better scores than images in THI mode alone (p imaging methods improve image quality of the soft tissues of neck and may be included in the routine settings of ultrasound systems.

  6. PANDA: a pipeline toolbox for analyzing brain diffusion images.

    Science.gov (United States)

    Cui, Zaixu; Zhong, Suyu; Xu, Pengfei; He, Yong; Gong, Gaolang

    2013-01-01

    Diffusion magnetic resonance imaging (dMRI) is widely used in both scientific research and clinical practice in in-vivo studies of the human brain. While a number of post-processing packages have been developed, fully automated processing of dMRI datasets remains challenging. Here, we developed a MATLAB toolbox named "Pipeline for Analyzing braiN Diffusion imAges" (PANDA) for fully automated processing of brain diffusion images. The processing modules of a few established packages, including FMRIB Software Library (FSL), Pipeline System for Octave and Matlab (PSOM), Diffusion Toolkit and MRIcron, were employed in PANDA. Using any number of raw dMRI datasets from different subjects, in either DICOM or NIfTI format, PANDA can automatically perform a series of steps to process DICOM/NIfTI to diffusion metrics [e.g., fractional anisotropy (FA) and mean diffusivity (MD)] that are ready for statistical analysis at the voxel-level, the atlas-level and the Tract-Based Spatial Statistics (TBSS)-level and can finish the construction of anatomical brain networks for all subjects. In particular, PANDA can process different subjects in parallel, using multiple cores either in a single computer or in a distributed computing environment, thus greatly reducing the time cost when dealing with a large number of datasets. In addition, PANDA has a friendly graphical user interface (GUI), allowing the user to be interactive and to adjust the input/output settings, as well as the processing parameters. As an open-source package, PANDA is freely available at http://www.nitrc.org/projects/panda/. This novel toolbox is expected to substantially simplify the image processing of dMRI datasets and facilitate human structural connectome studies.

  7. Role of PROPELLER diffusion weighted imaging and apparent diffusion coefficient in the diagnosis of sellar and parasellar lesions

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoud, Omar M., E-mail: omarmostafa2008@yahoo.co [Department of Neurosurgery, Graduate School of Biomedical Science, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551 (Japan); Department of Radiology, South Egypt Cancer Institute, Assiut University, Assiut 71515 (Egypt); Tominaga, Atsushi, E-mail: atom@hiroshima-u.ac.j [Department of Neurosurgery, Graduate School of Biomedical Science, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551 (Japan); Amatya, Vishwa Jeet, E-mail: amatya@hiroshima-u.ac.j [Department of Pathology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8551 (Japan); Ohtaki, Megu, E-mail: ohtaki@hiroshima-u.ac.j [Department of Environmetrics and Biometrics, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8551 (Japan); Sugiyama, Kazuhiko, E-mail: brain@hiroshima-u.ac.j [Department of Neurosurgery, Graduate School of Biomedical Science, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551 (Japan); Saito, Taiichi, E-mail: taiichi@hiroshima-u.ac.j [Department of Neurosurgery, Graduate School of Biomedical Science, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551 (Japan); Sakoguchi, Tetsuhiko, E-mail: sakog@hiroshima-u.ac.j [Department of Neurosurgery, Graduate School of Biomedical Science, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551 (Japan); Kinoshita, Yasuyuki, E-mail: d055634@hiroshima-u.ac.j [Department of Neurosurgery, Graduate School of Biomedical Science, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551 (Japan); Shrestha, Prabin, E-mail: prabinshrestha@hotmail.co [Department of Neurosurgery, Graduate School of Biomedical Science, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551 (Japan); Abe, Nobukazu, E-mail: abebe@hiroshima-u.ac.j [Dept. of Clinical Radiology, Graduate School of Biomedical Sciences, Hiroshima Univ., Hiroshima 734-8551 (Japan)

    2010-06-15

    Objective: To evaluate the role of the apparent diffusion coefficient (ADC) using periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) diffusion weighted imaging (DWI) in the differentiation between sellar and parasellar mass lesions. Materials and methods: The study protocol was approved by our institutional review board. We retrospectively studied 60 patients with sellar and parasellar lesions who had undergone PROPELLER DWI on a 3-T MR imager. Conventional MRI findings were expressed as the ratio of signal intensity (SI) in the lesions to the normal white matter and the degree of contrast enhancement. ADC values were calculated as the minimum (ADC-MIN), mean (ADC-MEAN), and maximum (ADC-MAX). All patients underwent surgery and all specimens were examined histologically. Logistic discriminant analysis was performed by using the SI ratios on T1- and T2-weighted images (T1-WI, T2-WI), the degree of enhancement, and absolute ADC values as independent variables. Results: ADC-MIN of hemorrhagic pituitary adenomas was lower than of the other lesions with similar appearance on conventional MRI (non-hemorrhagic pituitary adenomas, craniopharyngiomas, Rathke's cleft cysts; accuracy 100%); the useful cut-off value was 0.700 x 10{sup -3} mm{sup 2}/s. ADC-MAX of meningiomas was lower than of non-hemorrhagic pituitary adenomas (accuracy 90.3%; p < 0.01). ADC-MIN of craniopharyngiomas was lower than of Rathke's cleft cysts (accuracy 100%; p < 0.05). Conclusion: As PROPELLER DWI is less sensitive to susceptibility artifacts than single-shot echoplanar DWI, it is more useful in the examination of sellar and parasellar lesions. Calculation of the ADC values helps to differentiate between various sellar and parasellar lesions.

  8. The Disruption of Geniculocalcarine Tract in Occipital Neoplasm: A Diffusion Tensor Imaging Study

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    2016-01-01

    Full Text Available Aim. Investigate the disruption of geniculocalcarine tract (GCT in different occipital neoplasm by diffusion tensor imaging (DTI. Methods. Thirty-two subjects (44.1 ± 3.6 years who had single occipital neoplasm (9 gliomas, 6 meningiomas, and 17 metastatic tumors with ipsilateral GCT involved and thirty healthy subjects (39.2 ± 3.3 years underwent conventional sequences scanning and diffusion tensor imaging by a 1.5T MR scanner. The diffusion-sensitive gradient direction is 13. Compare the fractional anisotropy (FA and mean diffusivity (MD values of healthy GCT with the corresponding values of GCT in peritumoral edema area. Perform diffusion tensor tractography (DTT on GCT by the line propagation technique in all subjects. Results. The FA values of GCT in peritumoral edema area decreased (P=0.001 while the MD values increased (P=0.002 when compared with healthy subjects. There was no difference in the FA values across tumor types (P=0.114 while the MD values of GCT in the metastatic tumor group were higher than the other groups (P=0.001. GCTs were infiltrated in all the 9 gliomas cases, with displacement in 2 cases and disruption in 7 cases. GCTs were displaced in 6 meningiomas cases. GCTs were displaced in all the 7 metastatic cases, with disruption in 7 cases. Conclusions. DTI represents valid markers for evaluating GCT’s disruption in occipital neoplasm. The disruption of GCT varies according to the properties of neoplasm.

  9. Fast quantitative diffusion-tensor imaging of cerebral white matter from the neonatal period to adolescence

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, J.F.L.; Martin, E. [Department of Neuroradiology and Magnetic Resonance Imaging, University Children' s Hospital, Steinwiesstrasse 75, 8032, Zuerich (Switzerland); Il' yasov, K.A.; Hennig, J. [Department of Diagnostic Radiology, Section of Medical Physics, University Medical Centre, Hugstetter Strasse 55, 79106, Freiburg (Germany)

    2004-04-01

    We investigated the isotropic diffusion coefficient (D') and fractional anisotropy (FA) in white matter (WM) during brain development, using an optimised diffusion-tensor imaging (DTI) method with whole brain coverage in a clinically acceptable time. We images 52 children with no evident neurological abnormality (30 boys, 22 girls aged 1 day-16 years) using high-angle DTI with optimised temporal gradient performance. D' and FA were calculated in 10 regions of interest in white matter. We saw that the age-related reduction in D' and increase in FA follow a mono- or biexponential model in white matter, probably depending on the compactness and myelination rate of the fibre tracts. In contrast to other areas, in which adult values were reached during the third year, there is a trend to continuous increase in FA in all deep white-matter areas, suggesting continuing maturation and organisation of deep tracts not detected on conventional MRI. (orig.)

  10. Imaging in early rheumatoid arthritis: roles of magnetic resonance imaging, ultrasonography, conventional radiography and computed tomography

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Ejbjerg, Bo; Szkudlarek, Marcin

    2005-01-01

    Efficient methods for diagnosis, monitoring and prognostication are essential in early rheumatoid arthritis (RA). While conventional X-rays only visualize the late signs of preceding disease activity, there is evidence for magnetic resonance imaging (MRI) and ultrasonography being highly sensitive...... for early inflammatory and destructive changes in RA joints, and for MRI findings being sensitive to change and of predictive value for future progressive X-ray damage. Reviewing the data on X-ray, computed tomography, MRI and ultrasonography in RA, this paper discusses current and future roles...... of these imaging modalities in the management of early RA. The main focus is on recent advances in MRI and ultrasonography. Suggestions on clinical use and research priorities are provided...

  11. Photoacoustic imaging of prostate cancer using cylinder diffuse radiation

    Science.gov (United States)

    Xie, Wenming; Li, Li; Li, Zhifang; Li, Hui

    2012-12-01

    Prostate cancer is one of diseases with high mortality in man. Many clinical imaging modalities are utilized for the detection, grading and staging of prostate cancer, such as ultrasound, CT, MRI, etc. But they lacked adequate sensitivity and specificity for finding cancer in transition or central zone of prostate. To overcome these problems, we propose a photoacoustic imaging modality based on cylinder diffuse radiation through urethra for prostate cancer detection. We measure the related parameters about this system like lateral resolution (~2mm) and axial resolution(~333μm). Finally, simulated sample was imaged by our system. The results demonstrate the feasibility for detecting prostate cancer by our system.

  12. Diffusion-weighted imaging in the diagnosis of enterovirus 71 encephalitis

    Energy Technology Data Exchange (ETDEWEB)

    Lian, Zhou-yang; Huang, Biao; Liang, Chang-hong (Department of Radiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong (China)), Email: cjr.huangbiao@vip.163.com; He, Shaoru; Guo, Yuxiong (Department of Pediatrics, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong (China))

    2012-03-15

    Background. In the early phase of viral encephalitis, conventional MRI may appear normal. Diffusion-weighted imaging (DWI) is a sensitive tool for detecting early changes in cellular function in the central nervous system. Purpose. To investigate the usefulness of DWI in the diagnosis of enterovirus 71 (EV71) encephalitis, and to determine whether DWI is superior to conventional MR sequences. Material and Methods. MRI scans in 26 patients were retrospectively evaluated for distribution of lesions on T1-weighted images (T1WI), T2-weighted images (T2WI), fluid-attenuated inversion recovery (FLAIR), and DWI. Contrast-to-noise ratios (CNRs) were calculated for all regions on each sequence and differences in the four MRI sequences were assessed using CNRs. Apparent diffusion coefficient (ADC) values were measured for all regions to look for true restriction of diffusion. Results. Fifteen out of 26 cases showed positive findings on MR imaging. The brain stem was involved in 11 patients, cortex and subcortical white matter in four patients. DWI was more sensitive in detecting the abnormalities (89.7%) compared to T2WI (48.7%), FLAIR (41.0%), and T1WI (35.9%), and the positive ratio of DWI was significantly higher compared to other sequences. Furthermore, no significant difference was found between T2WI and FLAIR (P 0.649). The corresponding mean CNRs were 8.73 +- 2.57, 83.59 +- 29.28, 24.22 +- 6.22, and 132.27 +- 78.32 on T1WI, T2WI, FLAIR, and DWI, respectively. The absolute values of CNRs of lesions on DWI were significantly greater than those on other sequences. Conclusion. DWI appears to be more sensitive in detecting EV71 encephalitis than conventional MRI sequences. This capability may improve the accuracy in diagnosing EV71 encephalitis, especially at the early stage

  13. Diffusion tensor imaging of hemispheric asymmetries in the developing brain.

    Science.gov (United States)

    Wilde, Elisabeth A; McCauley, Stephen R; Chu, Zili; Hunter, Jill V; Bigler, Erin D; Yallampalli, Ragini; Wang, Zhiyue J; Hanten, Gerri; Li, Xiaoqi; Ramos, Marco A; Sabir, Sharjeel H; Vasquez, Ana C; Menefee, Deleene; Levin, Harvey S

    2009-02-01

    Diffusion tensor imaging (DTI) was performed in 39 right-handed children to examine structural hemispheric differences and the impact of age, socioeconomic status, and sex on these differences. Apparent diffusion coefficient (ADC) values were smaller in the left than in the right temporal, prefrontal, anterior internal capsular and the thalamic regions, and fractional anisotropy (FA) values were larger in the left than in the right internal capsule, thalamus, and cingulate. Significant region-by-sex interactions disclosed that the relation of DTI asymmetries to performance depended on sex including the relation of temporal lobes to reading comprehension and the relation of frontal lobes to solving applied mathematical problems.

  14. PANDA: a pipeline toolbox for analyzing brain diffusion images

    Directory of Open Access Journals (Sweden)

    Zaixu eCui

    2013-02-01

    Full Text Available Diffusion magnetic resonance imaging (dMRI is widely used in both scientific research and clinical practice in in-vivo studies of the human brain. While a number of post-processing packages have been developed, fully automated processing of dMRI datasets remains challenging. Here, we developed a MATLAB toolbox named Pipeline for Analyzing braiN Diffusion imAges (PANDA for fully automated processing of brain diffusion images. The processing modules of a few established packages, including FMRIB Software Library (FSL, Pipeline System for Octave and Matlab (PSOM, Diffusion Toolkit and MRIcron, were employed in PANDA. Using any number of raw dMRI datasets from different subjects, in either DICOM or NIfTI format, PANDA can automatically perform a series of steps to process DICOM/NIfTI to diffusion metrics (e.g., FA and MD that are ready for statistical analysis at the voxel-level, the atlas-level and the Tract-Based Spatial Statistics (TBSS-level and can finish the construction of anatomical brain networks for all subjects. In particular, PANDA can process different subjects in parallel, using multiple cores either in a single computer or in a distributed computing environment, thus greatly reducing the time cost when dealing with a large number of datasets. In addition, PANDA has a friendly graphical user interface (GUI, allowing the user to be interactive and to adjust the input/output settings, as well as the processing parameters. As an open-source package, PANDA is freely available at http://www.nitrc.org/projects/panda/. This novel toolbox is expected to substantially simplify the image processing of dMRI datasets and facilitate human structural connectome studies.

  15. White matter biomarkers from fast protocols using axially symmetric diffusion kurtosis imaging

    CERN Document Server

    Hansen, Brian; Shemesh, Noam; Lund, Torben E; Sangill, Ryan; Østergaard, Leif; Jespersen, Sune N

    2016-01-01

    White matter tract integrity (WMTI) can be used to characterize tissue microstructure in areas with axisymmetric fiber bundles. Several WMTI biomarkers have now been validated against microscopy and provided promising results in studies of brain development and aging, as well as in a number of brain disorders. In a clinical setting, however, the diffusion kurtosis imaging (DKI) protocol utilized as part of WMTI imaging may be prohibitively long. Consequently, the diagnostic value of the WMTI parameters is rarely explored outside of dedicated animal studies and clinical studies of slowly progressing diseases. Here, we evaluate WMTI based on recently introduced axially symmetric DKI which has lower data demand than conventional DKI. We compare WMTI parameters derived from conventional DKI to those from axially symmetric DKI and to parameters calculated analytically from the axially symmetric tensors. We also assess the effect of the imposed symmetry on the kurtosis fractional anisotropy (KFA). We employ numeric...

  16. Diffused Matrix Format: A New Storage and Processing Format for Airborne Hyperspectral Sensor Images

    Directory of Open Access Journals (Sweden)

    Pablo Martínez

    2010-05-01

    Full Text Available At present, hyperspectral images are mainly obtained with airborne sensors that are subject to turbulences while the spectrometer is acquiring the data. Therefore, geometric corrections are required to produce spatially correct images for visual interpretation and change detection analysis. This paper analyzes the data acquisition process of airborne sensors. The main objective is to propose a new data format called Diffused Matrix Format (DMF adapted to the sensor's characteristics including its spectral and spatial information. The second objective is to compare the accuracy of the quantitative maps derived by using the DMF data structure with those obtained from raster images based on traditional data structures. Results show that DMF processing is more accurate and straightforward than conventional image processing of remotely sensed data with the advantage that the DMF file structure requires less storage space than other data formats. In addition the data processing time does not increase when DMF is used.

  17. Fluorescence cell imaging and manipulation using conventional halogen lamp microscopy.

    Directory of Open Access Journals (Sweden)

    Kazuo Yamagata

    Full Text Available Technologies for vitally labeling cells with fluorescent dyes have advanced remarkably. However, to excite fluorescent dyes currently requires powerful illumination, which can cause phototoxic damage to the cells and increases the cost of microscopy. We have developed a filter system to excite fluorescent dyes using a conventional transmission microscope equipped with a halogen lamp. This method allows us to observe previously invisible cell organelles, such as the metaphase spindle of oocytes, without causing phototoxicity. Cells remain healthy even after intensive manipulation under fluorescence observation, such as during bovine, porcine and mouse somatic cell cloning using nuclear transfer. This method does not require expensive epifluorescence equipment and so could help to reduce the science gap between developed and developing countries.

  18. Semiautomated spleen volumetry with diffusion-weighted MR imaging.

    Science.gov (United States)

    Lee, Jeongjin; Kim, Kyoung Won; Lee, Ho; Lee, So Jung; Choi, Sanghyun; Jeong, Woo Kyoung; Kye, Heewon; Song, Gi-Won; Hwang, Shin; Lee, Sung-Gyu

    2012-07-01

    In this article, we determined the relative accuracy of semiautomated spleen volumetry with diffusion-weighted (DW) MR images compared to standard manual volumetry with DW-MR or CT images. Semiautomated spleen volumetry using simple thresholding followed by 3D and 2D connected component analysis was performed with DW-MR images. Manual spleen volumetry was performed on DW-MR and CT images. In this study, 35 potential live liver donor candidates were included. Semiautomated volumetry results were highly correlated with manual volumetry results using DW-MR (r = 0.99; P volumetry was significantly shorter compared to that of manual volumetry with DW-MR (P volumetry with DW-MR images can be performed rapidly and accurately when compared with standard manual volumetry.

  19. Diffusion-weighted imaging findings of adnexal torsion: Initial results

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Shinya, E-mail: sfujii@grape.med.tottori-u.ac.jp [Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine, Tottori University, 36-1 Nishi-cho, Yonago, Tottori 683-8504 (Japan); Kaneda, Sachi; Kakite, Suguru; Kanasaki, Yoshiko; Matsusue, Eiji [Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine, Tottori University, 36-1 Nishi-cho, Yonago, Tottori 683-8504 (Japan); Harada, Tasuku [Division of Reproductive-Perinatal Medicine and Gynecological Oncology, Department of Surgery, Faculty of Medicine, Tottori University, Yonago (Japan); Kaminou, Toshio; Ogawa, Toshihide [Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine, Tottori University, 36-1 Nishi-cho, Yonago, Tottori 683-8504 (Japan)

    2011-02-15

    Our purpose is to clarify the diffusion-weighted (DW) imaging findings of adnexal torsion. We retrospectively analyzed the DW imaging findings in 11 consecutive patients with surgical confirmation of adnexal torsion. We assessed signal intensity of the adnexal mass and fallopian tube thickening, and the location of abnormal signal intensity within the adnexal mass. On DW imaging, thickening of the fallopian tube was apparent as abnormal signal intensity in 8 of 11 patients. Abnormal signal intensity was inhomogeneous in 7 of 8 patients. Abnormal signal intensity on DW imaging was observed in 10 of 11 adnexal masses, and in the walls of 7 out of 8 adnexal cystic lesions. In adnexal torsion, DW imaging showed abnormal signal intensity in the thickened fallopian tube and in the wall of cystic ovarian lesions. These findings would be feasible to diagnose adnexal torsion.

  20. Fast dictionary-based reconstruction for diffusion spectrum imaging.

    Science.gov (United States)

    Bilgic, Berkin; Chatnuntawech, Itthi; Setsompop, Kawin; Cauley, Stephen F; Yendiki, Anastasia; Wald, Lawrence L; Adalsteinsson, Elfar

    2013-11-01

    Diffusion spectrum imaging reveals detailed local diffusion properties at the expense of substantially long imaging times. It is possible to accelerate acquisition by undersampling in q-space, followed by image reconstruction that exploits prior knowledge on the diffusion probability density functions (pdfs). Previously proposed methods impose this prior in the form of sparsity under wavelet and total variation transforms, or under adaptive dictionaries that are trained on example datasets to maximize the sparsity of the representation. These compressed sensing (CS) methods require full-brain processing times on the order of hours using MATLAB running on a workstation. This work presents two dictionary-based reconstruction techniques that use analytical solutions, and are two orders of magnitude faster than the previously proposed dictionary-based CS approach. The first method generates a dictionary from the training data using principal component analysis (PCA), and performs the reconstruction in the PCA space. The second proposed method applies reconstruction using pseudoinverse with Tikhonov regularization with respect to a dictionary. This dictionary can either be obtained using the K-SVD algorithm, or it can simply be the training dataset of pdfs without any training. All of the proposed methods achieve reconstruction times on the order of seconds per imaging slice, and have reconstruction quality comparable to that of dictionary-based CS algorithm.

  1. Assessment of tissue heterogeneity using diffusion tensor and diffusion kurtosis imaging for grading gliomas

    Energy Technology Data Exchange (ETDEWEB)

    Raja, Rajikha; Sinha, Neelam [International Institute of Information Technology-Bangalore, Bangalore (India); Saini, Jitender; Mahadevan, Anita; Rao, K.V.L. Narasinga; Swaminathan, Aarthi [National Institute of Mental Health and Neurosciences, Bangalore (India)

    2016-12-15

    In this work, we aim to assess the significance of diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) parameters in grading gliomas. Retrospective studies were performed on 53 subjects with gliomas belonging to WHO grade II (n = 19), grade III (n = 20) and grade IV (n = 14). Expert marked regions of interest (ROIs) covering the tumour on T2-weighted images. Statistical texture measures such as entropy and busyness calculated over ROIs on diffusion parametric maps were used to assess the tumour heterogeneity. Additionally, we propose a volume heterogeneity index derived from cross correlation (CC) analysis as a tool for grading gliomas. The texture measures were compared between grades by performing the Mann-Whitney test followed by receiver operating characteristic (ROC) analysis for evaluating diagnostic accuracy. Entropy, busyness and volume heterogeneity index for all diffusion parameters except fractional anisotropy and anisotropy of kurtosis showed significant differences between grades. The Mann-Whitney test on mean diffusivity (MD), among DTI parameters, resulted in the highest discriminability with values of P = 0.029 (0.0421) for grade II vs. III and P = 0.0312 (0.0415) for III vs. IV for entropy (busyness). In DKI, mean kurtosis (MK) showed the highest discriminability, P = 0.018 (0.038) for grade II vs. III and P = 0.022 (0.04) for III vs. IV for entropy (busyness). Results of CC analysis illustrate the existence of homogeneity in volume (uniformity across slices) for lower grades, as compared to higher grades. Hypothesis testing performed on volume heterogeneity index showed P values of 0.0002 (0.0001) and 0.0003 (0.0003) between grades II vs. III and III vs. IV, respectively, for MD (MK). In summary, the studies demonstrated great potential towards automating grading gliomas by employing tumour heterogeneity measures on DTI and DKI parameters. (orig.)

  2. Contribution of diffusion-weighted MR imaging for predicting benignity of complex adnexal masses

    Energy Technology Data Exchange (ETDEWEB)

    Thomassin-Naggara, Isabelle [Hopital Tenon, Assistance Publique Hopitaux de Pariss, Department of Radiology, Paris (France); Universite Rene Descartes, LRI-EA4062, Paris (France); Darai, Emile [Hopital Tenon, Assistance Publique Hopitaux de Pariss, Department of Gynecology-Obstetrics, Paris (France); Cuenod, Charles A.; Fournier, Laure [Universite Rene Descartes, LRI-EA4062, Paris (France); Hopital Europeen Georges Pompidou (HEGP), Assistance Publique Hopitaux de Paris, Department of Radiology, Paris (France); Toussaint, Irwin; Marsault, Claude; Bazot, Marc [Hopital Tenon, Assistance Publique Hopitaux de Pariss, Department of Radiology, Paris (France)

    2009-06-15

    The purpose of this study was to prospectively assess the contribution of diffusion-weighted MR imaging (DWI) for characterizing complex adnexal masses. Seventy-seven women (22-87 years old) with complex adnexal masses (30 benign and 47 malignant) underwent MR imaging including DWI before surgery. Conventional morphological MR imaging criteria were recorded in addition to b{sub 1,000} signal intensity and apparent diffusion coefficient (ADC) measurements of cystic and solid components. Positive likelihood ratios (PLR) were calculated for predicting benignity and malignancy. The most significant criteria for predicting benignity were low b{sub 1,000} signal intensity within the solid component (PLR = 10.9), low T2 signal intensity within the solid component (PLR = 5.7), absence of solid portion (PLR = 3.1), absence of ascites or peritoneal implants (PLR = 2.3) and absence of papillary projections (PLR = 2.3). ADC measurements did not contribute to differentiating benign from malignant adnexal masses. All masses that displayed simultaneously low signal intensity within the solid component on T2-weighted and on b{sub 1,000} diffusion-weighted images were benign. Alternatively, the presence of a solid component with intermediate T2 signal and high b{sub 1,000} signal intensity was associated with a PLR of 4.5 for a malignant adnexal tumour. DWI signal intensity is an accurate tool for predicting benignity of complex adnexal masses. (orig.)

  3. Diffusion tensor imaging in the characterization of multiple system atrophy

    Directory of Open Access Journals (Sweden)

    Rulseh AM

    2016-08-01

    Full Text Available Aaron Michael Rulseh,1–3 Jiri Keller,1,4 Jan Rusz,5,6 Michael Syka,1 Hana Brozova,6 Robert Rusina,6,7 Petra Havrankova,6 Katerina Zarubova,8 Hana Malikova,1 Robert Jech,6 Josef Vymazal1 1Department of Radiology, Na Homolce Hospital, Prague, Czech Republic; 2Department of Radiology, 1st Faculty of Medicine, General University Hospital, Charles University in Prague, Prague, Czech Republic; 3National Institute of Mental Health, Klecany, Czech Republic; 43rd Faculty of Medicine, Charles University in Prague, Prague, Czech Republic; 5Department of Circuit Theory, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, Czech Republic; 6Department of Neurology and Centre of Clinical Neuroscience, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic; 7Thomayer Hospital, Prague, Czech Republic; 8Department of Neurology, 2nd Faculty of Medicine, Charles University in Prague, Prague, Czech Republic Purpose: Multiple system atrophy (MSA is a rare neurodegenerative disease that remains poorly understood, and the diagnosis of MSA continues to be challenging. We endeavored to improve the diagnostic process and understanding of in vivo characteristics of MSA by diffusion tensor imaging (DTI.Materials and methods: Twenty MSA subjects, ten parkinsonian dominant (MSA-P, ten cerebellar dominant (MSA-C, and 20 healthy volunteer subjects were recruited. Fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity maps were processed using tract-based spatial statistics. Diffusion data were additionally evaluated in the basal ganglia. A support vector machine was used to assess diagnostic utility, leave-one-out cross-validation in the evaluation of classification schemes, and receiver operating characteristic analyses to determine cutoff values.Results: We detected widespread changes in the brain white matter of MSA subjects; however, no group-wise differences were found between MSA-C and MSA

  4. Prediction of recovery from a post-traumatic coma state by diffusion-weighted imaging (DWI) in patients with diffuse axonal injury

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, W.B.; Liu, G.R.; Wu, R.H. [Shantou University Medical College, Department of Radiology, Second Hospital, Shantou, Guangdong (China); Li, L.P. [Shantou University Medical College, Injury Prevention Research Center, Shantou, Guangdong (China)

    2007-03-15

    To determine whether diffusion-weighted magnetic resonance (MR) imaging findings combined with initial clinical factors indicate the depth of shearing lesions in the brain structure and therefore relate to coma duration in diffuse axonal injury (DAI). A total of 74 adult patients (48 male and 26 female) with DAI were examined with conventional MR imaging and diffusion-weighted MR imaging between 2 hours and 20 days after injury. Apparent diffusion coefficient (ADC) maps were obtained and the mean ADC values of each region of interest (ROI) were measured using MRI console software. The involvement of the brainstem, deep gray matter, and corpus callosum was determined for each sequence separately as well as for the combination of all sequences. The correlations between MR imaging findings indicating the presence of apparent brain injury combined with initial clinical factors were determined. Clinical characteristics, such as initial score on the Glasgow coma scale (GCS), age and number of all lesions, and ADC scores were predictive of the duration of coma. It was possible to predict post-traumatic coma duration in DAI from cerebral MR imaging findings combined with clinical prognostic factors in the acute to subacute stage after head injury. Age, ADC scores, GCS score and number of lesions were highly significant in predicting coma duration. The technique presented here might provide a tool for in vivo detection of DAI to allow the prediction of the coma duration during the early stages in patients with traumatic brain injury. (orig.)

  5. Assessment of Activity of Crohn Disease by Diffusion-Weighted Magnetic Resonance Imaging

    Science.gov (United States)

    Li, Xue-hua; Sun, Can-hui; Mao, Ren; Zhang, Zhong-wei; Jiang, Xiao-song; Pui, Margaret H.; Chen, Min-hu; Li, Zi-ping

    2015-01-01

    Abstract To assess the diagnostic efficacy of diffusion-weighted MR imaging (DWI) for evaluating inflammatory activity in patients with Crohn's disease (CD). A total of 47 CD patients underwent MR enterography (MRE) and DWI using 3 b values of 50, 400, and 800 s/mm.2 Apparent diffusion coefficients (ADCs) of inflamed and normal bowel wall were calculated. The conventional MRE findings and DWI signal intensities were qualitatively scored from 0 to 3. The correlation between Crohn disease activity index (CDAI) and both ADCs and magnetic resonance imaging scores was analyzed. Receiver-operating characteristic curve analysis was used to determine the diagnostic accuracy of CD activity. Of the 47 patients, 25 were active CD (CDAI≥150) and 22 were inactive (CDAI<150). Diffusion-weighted MR imaging and MRE + DWI scores of active CD were significantly higher than that of inactive CD (both P < 0.001). Apparent diffusion coefficients in inflamed segments of active CD were lower than that of inactive CD (P < 0.001). The DWI scores (r = 0.74, P < 0.001), ADCs (r = −0.71, P < 0.001), MRE scores (r = 0.54, P < 0.001), and MRE + DWI scores (r = 0.66, P < 0.001) were all correlated with CDAI. The areas under the receiver-operating characteristics curves for ADCs, DWI scores, MRE scores, and MRE + DWI scores ranged from 0.83 to 0.98. The threshold ADC value of 1.17 × 10−3 mm2/s allowed differentiation of active from inactive CD with 100% sensitivity and 88% specificity. Diffusion-weighted MR imaging and ADC correlated with CD activity, and had excellent diagnostic accuracy for differentiating active from inactive CD. PMID:26512584

  6. Recurrence and metastasis of lung cancer demonstrate decreased diffusion on diffusion-weighted magnetic resonance imaging.

    Science.gov (United States)

    Usuda, Katsuo; Sagawa, Motoyasu; Motomo, Nozomu; Ueno, Masakatsu; Tanaka, Makoto; Machida, Yuichiro; Maeda, Sumiko; Matoba, Munetaka; Tonami, Hisao; Ueda, Yoshimichi; Sakuma, Tsutomu

    2014-01-01

    Diffusion-weighted magnetic resonance imaging (DWI) is reported to be useful for detecting malignant lesions. The purpose of this study is to clarify characteristics of imaging, detection rate and sensitivity of DWI for recurrence or metastasis of lung cancer. A total of 36 lung cancer patients with recurrence or metastasis were enrolled in this study. While 16 patients underwent magnetic resonance imaging (MRI), computed tomography (CT) and positron emission tomography-computed tomography (PET-CT), 17 underwent MRI and CT, and 3 underwent MRI and PET-CT. Each recurrence or metastasis showed decreased diffusion, which was easily recognized in DWI. The detection rate for recurrence or metastasis was 100% (36/36) in DWI, 89% (17/19) in PET-CT and 82% (27/33) in CT. Detection rate of DWI was significantly higher than that of CT (p=0.0244) but not significantly higher than that of PET-CT (p=0.22). When the optimal cutoff value of the apparent diffusion coefficient value was set as 1.70?10-3 mm2/sec, the sensitivity of DWI for diagnosing recurrence or metastasis of lung cancer was 95.6%. DWI is useful for detection of recurrence and metastasis of lung cancer.

  7. Diffusion imaging: technology and clinical application; Diffusionsbildgebung. Technik und klinische Anwendung

    Energy Technology Data Exchange (ETDEWEB)

    Kukuk, Guido Matthias; Greschus, Susanne; Pieper, Claus Christian [Universitaetsklinik Bonn (Germany). Radiologische Klinik; Goldstein, Jan [Staedtisches Klinikum Solingen (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie

    2017-03-15

    While diffusion imaging was predominantly used for cerebral ischemia diagnostics it is now a widely applied MR diagnostic tool for oncologic or inflammatory diseases. The contribution is focused on the fundamentals of diffusion imaging and the most important indications.

  8. Image segmentation and edge enhancement with stabilized inverse diffusion equations.

    Science.gov (United States)

    Pollak, I; Willsky, A S; Krim, H

    2000-01-01

    We introduce a family of first-order multidimensional ordinary differential equations (ODEs) with discontinuous right-hand sides and demonstrate their applicability in image processing. An equation belonging to this family is an inverse diffusion everywhere except at local extrema, where some stabilization is introduced. For this reason, we call these equations "stabilized inverse diffusion equations" (SIDEs). Existence and uniqueness of solutions, as well as stability, are proven for SIDEs. A SIDE in one spatial dimension may be interpreted as a limiting case of a semi-discretized Perona-Malik equation. In an experiment, SIDE's are shown to suppress noise while sharpening edges present in the input signal. Their application to image segmentation is also demonstrated.

  9. Imaging Nonequilibrium Atomic Vibrations with X-ray Diffuse Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Trigo, M.; Chen, J.; Vishwanath, V.H.; /SLAC; Sheu, Y.M.; /Michigan U.; Graber, T.; Henning, R.; /U. Chicago; Reis, D; /SLAC /Stanford U., Appl. Phys. Dept.

    2011-03-03

    We use picosecond x-ray diffuse scattering to image the nonequilibrium vibrations of the lattice following ultrafast laser excitation. We present images of nonequilibrium phonons in InP and InSb throughout the Brillouin-zone which remain out of equilibrium up to nanoseconds. The results are analyzed using a Born model that helps identify the phonon branches contributing to the observed features in the time-resolved diffuse scattering. In InP this analysis shows a delayed increase in the transverse acoustic (TA) phonon population along high-symmetry directions accompanied by a decrease in the longitudinal acoustic (LA) phonons. In InSb the increase in TA phonon population is less directional.

  10. Image denoising using a directional adaptive diffusion filter

    Science.gov (United States)

    Zhao, Cuifang; Shi, Caicheng; He, Peikun

    2006-11-01

    Partial differential equations (PDEs) are well-known due to their good processing results which it can not only smooth the noise but also preserve the edges. But the shortcomings of these processes came to being noticed by people. In some sense, PDE filter is called "cartoon model" as it produces an approximation of the input image, use the same diffusion model and parameters to process noise and signal because it can not differentiate them, therefore, the image is naturally modified toward piecewise constant functions. A new method called a directional adaptive diffusion filter is proposed in the paper, which combines PDE mode with wavelet transform. The undecimated discrete wavelet transform (UDWT) is carried out to get different frequency bands which have obviously directional selectivity and more redundancy details. Experimental results show that the proposed method provides a performance better to preserve textures, small details and global information.

  11. Application of diffusion tensor imaging in multiple sclerosis

    OpenAIRE

    Sousa, Filipa Costa

    2015-01-01

    Trabalho final de mestrado integrado em Medicina, apresentado à Faculdade de Medicina da Universidade de Coimbra. Multiple sclerosis (MS) is a degenerative disease of the central nervous system (CNS), being a significant cause of disability. During the last years, diffusion tensor imaging (DTI) has been applied in the study of MS patients in an attempt to improve the understanding of the pathologic process at a microstructural level, in early stages of the disease. DTI, due to its high sen...

  12. Diffusion MR imaging in sporadic Creutzfeldt-Jakob disease

    Directory of Open Access Journals (Sweden)

    Burcak Cakir Pekoz

    2014-08-01

    Full Text Available Creutzfeldt-Jakob disease (CJD is a rare dementing disease and is thought to caused by a prion. It is characterized by rapidly progressive dementia, ataxia, myoclonus, akinetic mutism and eventual death. Brain biopsy or autopsy is required for a definitive diagnosis of CJD. Diffusion-weighted imaging became an important tool for early diagnosis of CJD because of the high sensitivity. We present 59-year-old female patient diagnosed as sporadic CJD with typical MR imagings. [Cukurova Med J 2014; 39(4.000: 880-883

  13. Comparative effects of Facebook and conventional media on body image dissatisfaction.

    Science.gov (United States)

    Cohen, Rachel; Blaszczynski, Alex

    2015-01-01

    Appearance comparison has consistently been shown to engender body image dissatisfaction. To date, most studies have demonstrated this relationship between appearance comparison and body image dissatisfaction in the context of conventional media images depicting the thin-ideal. Social comparison theory posits that people are more likely to compare themselves to similar others. Since social media forums such as Facebook involve one's peers, the current study aimed to determine whether the relationship between appearance comparison and body image dissatisfaction would be stronger for those exposed to social media images, compared to conventional media images. A sample of 193 female first year university students were randomly allocated to view a series of either Facebook or conventional media thin-ideal images. Participants completed questionnaires assessing pre- and post- image exposure measures of thin-ideal internalisation, appearance comparison, self-esteem, Facebook use and eating disorder risk. Type of exposure was not found to moderate the relationship between appearance comparison and changes in body image dissatisfaction. When analysed according to exposure type, appearance comparison only significantly predicted body image dissatisfaction change for those exposed to Facebook, but not conventional media. Facebook use was found to predict higher baseline body image dissatisfaction and was associated with higher eating disorder risk. The findings suggest the importance of extending the body image dissatisfaction literature by taking into account emerging social media formats. It is recommended that interventions for body image dissatisfaction and eating disorders consider appearance comparison processes elicited by thin-ideal content on social media forums, such as Facebook, in addition to conventional media.

  14. Diffusion tensor imaging of midline posterior fossa malformations

    Energy Technology Data Exchange (ETDEWEB)

    Widjaja, Elysa; Blaser, Susan; Raybaud, Charles [Hospital for Sick Children, Diagnostic Imaging, Toronto, ON M5G 1X8 (Canada)

    2006-06-15

    Diffusion tensor imaging and tractography have been used to evaluate a variety of brain malformations. However, these studies have focused mainly on malformations involving the supratentorial compartments. There is a paucity of data on diffusion tensor imaging of posterior fossa malformations. To describe the color vector maps and modified or abnormal tracts of midline posterior fossa malformations. Diffusion tensor imaging was performed in one patient with rhombencephalosynapsis and two with Joubert syndrome. Color vector maps of fractional anisotropy were used to place a region of interest for seed point of fiber tracking. The vermis was severely hypoplastic or absent in rhombencephalosynapsis and Joubert syndrome. In rhombencephalosynapsis, vertically oriented fibers were visualized in the midportion of the cerebellum. The location of the deep cerebellar nuclei could be inferred from the amiculum and were medially located in rhombencephalosynapsis. In the two patients with Joubert syndrome, the horizontally arranged superior cerebellar peduncles were well demonstrated on the color vector maps. Failure of the superior cerebellar peduncles to decussate in the mesencephalon was also well demonstrated on both color vector maps and tractography. The deep cerebellar nuclei were more laterally located in Joubert syndrome. The use of tractography in midline posterior fossa malformations expands our understanding of these malformations. (orig.)

  15. A novel image inpainting technique based on median diffusion

    Indian Academy of Sciences (India)

    Rajkumar L Biradar; Vinayadatt V Kohir

    2013-08-01

    Image inpainting is the technique of filling-in the missing regions and removing unwanted objects from an image by diffusing the pixel information from the neighbourhood pixels. Image inpainting techniques are in use over a long time for various applications like removal of scratches, restoring damaged/missing portions or removal of objects from the images, etc. In this study, we present a simple, yet unexplored (digital) image inpainting technique using median filter, one of the most popular nonlinear (order statistics) filters. The median is maximum likelihood estimate of location for the Laplacian distribution. Hence, the proposed algorithm diffuses median value of pixels from the exterior area into the inner area to be inpainted. The median filter preserves the edge which is an important property needed to inpaint edges. This technique is stable. Experimental results show remarkable improvements and works for homogeneous as well as heterogeneous background. PSNR (quantitative assessment) is used to compare inpainting results.

  16. Spatio-temporal diffusion of dynamic PET images

    Energy Technology Data Exchange (ETDEWEB)

    Tauber, C; Chalon, S; Guilloteau, D [Inserm U930, CNRS ERL3106, Universite Francois Rabelais, Tours (France); Stute, S; Buvat, I [IMNC, IN2P3, UMR 8165 CNRS-Paris 7 and Paris 11 Universities, Orsay (France); Chau, M [ASA-Advanced Solutions Accelerator, Montpellier (France); Spiteri, P, E-mail: clovis.tauber@univ-tours.fr [IRIT-ENSEEIHT, UMR CNRS 5505, Toulouse (France)

    2011-10-21

    Positron emission tomography (PET) images are corrupted by noise. This is especially true in dynamic PET imaging where short frames are required to capture the peak of activity concentration after the radiotracer injection. High noise results in a possible bias in quantification, as the compartmental models used to estimate the kinetic parameters are sensitive to noise. This paper describes a new post-reconstruction filter to increase the signal-to-noise ratio in dynamic PET imaging. It consists in a spatio-temporal robust diffusion of the 4D image based on the time activity curve (TAC) in each voxel. It reduces the noise in homogeneous areas while preserving the distinct kinetics in regions of interest corresponding to different underlying physiological processes. Neither anatomical priors nor the kinetic model are required. We propose an automatic selection of the scale parameter involved in the diffusion process based on a robust statistical analysis of the distances between TACs. The method is evaluated using Monte Carlo simulations of brain activity distributions. We demonstrate the usefulness of the method and its superior performance over two other post-reconstruction spatial and temporal filters. Our simulations suggest that the proposed method can be used to significantly increase the signal-to-noise ratio in dynamic PET imaging.

  17. Edge-Based Image Compression with Homogeneous Diffusion

    Science.gov (United States)

    Mainberger, Markus; Weickert, Joachim

    It is well-known that edges contain semantically important image information. In this paper we present a lossy compression method for cartoon-like images that exploits information at image edges. These edges are extracted with the Marr-Hildreth operator followed by hysteresis thresholding. Their locations are stored in a lossless way using JBIG. Moreover, we encode the grey or colour values at both sides of each edge by applying quantisation, subsampling and PAQ coding. In the decoding step, information outside these encoded data is recovered by solving the Laplace equation, i.e. we inpaint with the steady state of a homogeneous diffusion process. Our experiments show that the suggested method outperforms the widely-used JPEG standard and can even beat the advanced JPEG2000 standard for cartoon-like images.

  18. Evaluation of conventional, dynamic contrast enhanced and diffusion weighted MRI for quantitative Crohn's disease assessment with histopathology of surgical specimens

    Energy Technology Data Exchange (ETDEWEB)

    Tielbeek, Jeroen A.W.; Ziech, Manon L.W.; Lavini, Cristina; Bipat, Shandra; Stoker, Jaap [University of Amsterdam, Academic Medical Center, Department of Radiology, Amsterdam (Netherlands); Li, Zhang [Delft University of Technology, Quantitative Imaging Group, Department of Imaging Science and Technology, Delft (Netherlands); Bemelman, Willem A. [University of Amsterdam, Academic Medical Center, Department of Surgery, Amsterdam (Netherlands); Roelofs, Joris J.T.H. [University of Amsterdam, Academic Medical Center, Department of Pathology, Amsterdam (Netherlands); Ponsioen, Cyriel Y. [University of Amsterdam, Academic Medical Center, Department of Gastroenterology and Hepatology, Amsterdam (Netherlands); Vos, Frans M. [University of Amsterdam, Academic Medical Center, Department of Radiology, Amsterdam (Netherlands); Delft University of Technology, Quantitative Imaging Group, Department of Imaging Science and Technology, Delft (Netherlands)

    2014-03-15

    To prospectively compare conventional MRI sequences, dynamic contrast enhanced (DCE) MRI and diffusion weighted imaging (DWI) with histopathology of surgical specimens in Crohn's disease. 3-T MR enterography was performed in consecutive Crohn's disease patients scheduled for surgery within 4 weeks. One to four sections of interest per patient were chosen for analysis. Evaluated parameters included mural thickness, T1 ratio, T2 ratio; on DCE-MRI maximum enhancement (ME), initial slope of increase (ISI), time-to-peak (TTP); and on DWI apparent diffusion coefficient (ADC). These were compared with location-matched histopathological grading of inflammation (AIS) and fibrosis (FS) using Spearman correlation, Kruskal-Wallis and Chi-squared tests. Twenty patients (mean age 38 years, 12 female) were included and 50 sections (35 terminal ileum, 11 ascending colon, 2 transverse colon, 2 descending colon) were matched to AIS and FS. Mural thickness, T1 ratio, T2 ratio, ME and ISI correlated significantly with AIS, with moderate correlation (r = 0.634, 0.392, 0.485, 0.509, 0.525, respectively; all P < 0.05). Mural thickness, T1 ratio, T2 ratio, ME, ISI and ADC correlated significantly with FS (all P < 0.05). Quantitative parameters from conventional, DCE-MRI and DWI sequences correlate with histopathological scores of surgical specimens. DCE-MRI and DWI parameters provide additional information. (orig.)

  19. CT guided diffuse optical tomography for breast cancer imaging

    Science.gov (United States)

    Baikejiang, Reheman; Zhang, Wei; Zhu, Dianwen; Li, Changqing

    2016-03-01

    Diffuse optical tomography (DOT) has attracted attentions in the last two decades due to its intrinsic sensitivity in imaging chromophores of tissues such as blood, water, and lipid. However, DOT has not been clinically accepted yet due to its low spatial resolution caused by strong optical scattering in tissues. Structural guidance provided by an anatomical imaging modality enhances the DOT imaging substantially. Here, we propose a computed tomography (CT) guided multispectral DOT imaging system for breast cancer detection. To validate its feasibility, we have built a prototype DOT imaging system which consists of a laser at wavelengths of 650 and an electron multiplying charge coupled device (EMCCD) camera. We have validated the CT guided DOT reconstruction algorithms with numerical simulations and phantom experiments, in which different imaging setup parameters, such as projection number of measurements, the width of measurement patch, have been investigated. Our results indicate that an EMCCD camera with air cooling is good enough for the transmission mode DOT imaging. We have also found that measurements at six projections are sufficient for DOT to reconstruct the optical targets with 4 times absorption contrast when the CT guidance is applied. Finally, we report our effort and progress on the integration of the multispectral DOT imaging system into a breast CT scanner.

  20. Gastrointestinal stromal tumours: Correlation of modified NIH risk stratification with diffusion-weighted MR imaging as an imaging biomarker

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Tae Wook [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710 (Korea, Republic of); Kim, Seong Hyun, E-mail: kshyun@skku.edu [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710 (Korea, Republic of); Jang, Kyung Mi; Choi, Dongil [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710 (Korea, Republic of); Ha, Sang Yun; Kim, Kyoung-Mee [Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710 (Korea, Republic of); Kang, Won Ki [Division of Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710 (Korea, Republic of); Kim, Min Ji [Biostatics Unit, Samsung Biomedical Research Institute, Samsung Medical Center, Seoul 135-710 (Korea, Republic of)

    2015-01-15

    Highlights: • Except size and necrosis, conventional MR findings of GISTs were not significantly different according to the modified NIH criteria. • The ADC values of GISTs were negatively correlated with the modified NIH criteria. • The ADC value can be helpful for the determination of intermediate or high-risk GISTs. - Abstract: Purpose: To evaluate the correlation of risk grade of gastrointestinal stromal tumours (GISTs) based on modified National Institutes of Health (NIH) criteria with conventional magnetic resonance (MR) imaging and diffusion-weighted (DW) imaging. Methods: We included 22 patients with histopathologically proven GISTs in the stomach or small bowel who underwent pre-operative gadoxetic acid-enhanced MR imaging and DW imaging. We retrospectively assessed correlations between morphologic findings, qualitative (signal intensity, consensus from two observers) and quantitative (degree of dynamic enhancement using signal intensity of tumour/muscle ratio and apparent diffusion coefficient [ADC]) values, and the modified NIH criteria for risk stratification. Spearman partial correlation analysis was used to control for tumour size as a confounding factor. The optimal cut-off level of ADC values for intermediate or high risk GISTs was analyzed using a receiver operating characteristic analysis. Results: Except tumour size and necrosis, conventional MR imaging findings, including the degree of dynamic enhancement, were not significantly different according to the modified NIH criteria (p > 0.05). Tumour ADC values were negatively correlated with the modified NIH criteria, before and after adjustment of tumour size (ρ = −0.754; p < 0.001 and ρ = −0.513; p = 0.017, respectively). The optimal cut-off value for the determination of intermediate or high-risk GISTs was 1.279 × 10{sup −3} mm{sup 2}/s (100% sensitivity, 69.2% specificity, 81.8% accuracy). Conclusion: Except tumour size and necrosis, conventional MR imaging findings did not

  1. Staging N0 Oral Cancer: Lymphoscintigraphy and Conventional Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Thomsen, J.B.; Soerensen, J.A.; Grupe, P.; Karstoft, J.; Krogdahl, A. [Odense Univ. Hospital (Denmark). Depts. of Plastic and Reconstructive Surgery, Nuclear Medicine, Radiology, and Pathology

    2005-08-01

    PURPOSE: To compare sentinel lymph node biopsy, magnetic resonance imaging (MRI), Doppler ultrasonography, and palpation as staging tools in patients with T1/T2 N0 cancer of the oral cavity. MATERIAL AND METHODS: Forty consecutive patients were enrolled (17 F and 23 M, aged 32-90 years), 24 T1 and 16 T2 cN0 squamous cell carcinoma of the oral cavity. Palpation was carried out by two observers prior to inclusion. MRI, gray-scale and Doppler ultrasonography were performed. Lymphoscintigraphies were done after peritumoral injections of 99mTc labelled rheniumsulphide nanocolloid, followed by sentinel lymph node biopsy guided by a gamma probe and Patent Blue. Palpation, Doppler ultrasonography, MRI, and sentinel lymph node biopsy were compared to a combination of histopathology and follow-up. Diagnostic testing was performed using the x2 test. RESULTS: Histopathological examination revealed metastatic spread to the neck in 14 of 40 patients. One patient had bilateral neck disease. Sentinel lymph node biopsy and ultrasonography were performed in 80 neck sides of 40 patients and MRI in 70 neck sides (5 patients were claustrophobic). SN revealed suspicious lymph nodes in 12 necks, ultrasonography in 23 necks, and MRI in 9 necks. The positive predictive value of sentinel lymph node biopsy was 100%, ultrasonography 57%, and MRI 56%. The respective negative predictive values were 96%, 96%, and 85%. The sensitivity of sentinel lymph node biopsy 80% was comparable to ultrasonography 87%, but the sensitivity of MRI 36% was low. The specificities were 100%, 85%, and 93%, respectively. By combined sentinel lymph node biopsy and ultrasonography the overall sensitivity could have been 100%. CONCLUSION: Sentinel lymph node biopsy improved staging of patients with small N0 oral cancers. Combined sentinel lymph node biopsy and Doppler ultrasonography may further improve staging. MRI and simple palpation results were poor.

  2. MR diffusion imaging and MR spectroscopy of maple syrup urine disease during acute metabolic decompensation

    Energy Technology Data Exchange (ETDEWEB)

    Jan, Wajanat; Wang, Zhiyue J. [Department of Radiology, University of Pennsylvania School of Medicine, Children' s Hospital of Philadelphia, Pennsylvania (United States); Zimmerman, Robert A. [Department of Radiology, University of Pennsylvania School of Medicine, Children' s Hospital of Philadelphia, Pennsylvania (United States); Department of Radiology, Children' s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, PA 19104, Philadelphia (United States); Berry, Gerard T.; Kaplan, Paige B.; Kaye, Edward M. [Department of Pediatrics, University of Pennsylvania School of Medicine, The Children' s Hospital of Philadelphia, Philadelphia, Pennsylvania (United States)

    2003-06-01

    Maple syrup urine disease (MSUD) is an inborn error of amino acid metabolism, which affects the brain tissue resulting in impairment or death if untreated. Imaging studies have shown reversible brain edema during acute metabolic decompensation. The purpose of this paper is to describe the diffusion-weighted imaging (DWI) and spectroscopy findings during metabolic decompensation and to assess the value of these findings in the prediction of patient outcome. Six patients with the diagnosis of MSUD underwent conventional MR imaging with DWI during acute presentation with metabolic decompensation. Spectroscopy with long TE was performed in four of the six patients. Follow-up examinations were performed after clinical and metabolic recovery. DWI demonstrated marked restriction of proton diffusion compatible with cytotoxic or intramyelinic sheath edema in the brainstem, basal ganglia, thalami, cerebellar and periventricular white matter and the cerebral cortex. This was accompanied by the presence of an abnormal branched-chain amino acids (BCAA) and branched-chain alpha-keto acids (BCKA) peak at 0.9 ppm as well as elevated lactate on proton spectroscopy in all four patients. The changes in all six patients were reversed with treatment without evidence of volume loss or persistent tissue damage. The presence of cytotoxic or intramyelinic edema as evidenced by restricted water diffusion on DWI, with the presence of lactate on spectroscopy, could imply imminent cell death. However, in the context of metabolic decompensation in MSUD, it appears that changes in cell osmolarity and metabolism can reverse completely after metabolic correction. (orig.)

  3. Diffusion tensor imaging of the cortical plate and subplate in very-low-birth-weight infants

    Energy Technology Data Exchange (ETDEWEB)

    Dudink, Jeroen; Govaert, Paul; Zwol, Arjen L. van; Conneman, Nikk; Goudoever, Johannes B. van [Erasmus MC-Sophia Children' s Hospital, Division of Neonatology, Department of Paediatrics, Rotterdam (Netherlands); Buijs, Jan [Maxima Medical Center, Division of Neonatology, Department of Paediatrics, Veldhoven (Netherlands); Lequin, Maarten [Erasmus MC-Sophia Children' s Hospital, Division of Paediatrics, Department of Radiology, Rotterdam, Zuid-holland (Netherlands)

    2010-08-15

    Many intervention studies in preterm infants aim to improve neurodevelopmental outcome, but short-term proxy outcome measurements are lacking. Cortical plate and subplate development could be such a marker. Our aim was to provide normal DTI reference values for the cortical plate and subplate of preterm infants. As part of an ongoing study we analysed diffusion tensor imaging (DTI) images of 19 preterm infants without evidence of injury on conventional MRI, with normal outcome (Bayley-II assessed at age 2), and scanned in the first 4 days of life. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values in the frontal and temporal subplate and cortical plate were measured in single and multiple voxel regions of interest (ROI) placed on predefined regions. Using single-voxel ROIs, statistically significant inverse correlation was found between gestational age (GA) and FA of the frontal (r = -0.5938, P = 0.0058) and temporal (r = -0.4912, P = 0.0327) cortical plate. ADC values had a significant positive correlation with GA in the frontal (r = 0.5427, P = 0.0164) and temporal (r = 0.5540, P = 0.0138) subplate. Diffusion tensor imaging allows in vivo exploration of the evolving cortical plate and subplate. We provide FA and ADC values of the subplate and cortical plate in very-low-birth-weight (VLBW) infants with normal developmental outcome that can be used as reference values. (orig.)

  4. Controversies of diffusion weighted imaging in the diagnosis of brain death.

    Science.gov (United States)

    Luchtmann, Michael; Bernarding, Johannes; Beuing, Oliver; Kohl, Jana; Bondar, Imre; Skalej, Martin; Firsching, Raimund

    2013-10-01

    Imaging techniques as confirmatory tests may add safety to the diagnosis of brain death, but are partly not accepted either because they are too invasive, such as conventional arterial angiography, or because there is still lack of evidence of its reliability, such as magnetic resonance angiography. In this study the reliability of diffusion weighted imaging for the diagnosis of brain death was evaluated according in terms of its sensitivity and specificity. The apparent diffusion coefficients (ADC) of 18 brain dead patients were registered from 14 distinct brain areas. The mean ADC values of the brain dead patients were compared with normal controls of physiological ADC values of unaffected brain tissue. Despite a highly significant decrease of the mean ADC value in 16 patients, two patients showed mean ADC values that were within normal physiological range. An explanation may be the pseudonormalization of ADC values seen in stroke patients that depends on the time of the onset of the brain damage. We conclude, diffusion-weighted imaging may provide additional information on damage of the brain tissue but is not a practicable confirmatory test for the reliable diagnosis of brain death.

  5. Disseminated primary diffuse leptomeningeal gliomatosis: a case report with liquid based and conventional smear cytology

    Directory of Open Access Journals (Sweden)

    Bilic Masha

    2005-09-01

    Full Text Available Abstract Background Primary diffuse leptomeningeal gliomatosis is a rare neoplasm confined to the meninges without evidence of primary tumor in the brain or spinal cord parenchyma. Cerebrospinal fluid diversion via ventriculoperitoneal shunt may be used as a therapeutic modality. Herein, we describe the first report of cytologic findings of a case of this neoplasm with shunt-related peritoneal metastasis. Case presentation A 19-year-old male presented with a 6-month history of severe headaches. He had bilateral papilledema on physical exam. Cerebrospinal fluid examination was negative. Four months later a ventriculoperitoneal shunt was placed. Shortly thereafter, he was diagnosed with primary diffuse leptomeningeal gliomatosis based on the biopsy of an intradural extramedullary lesion adjacent to the lumbar spinal cord at a referral cancer center. The histology featured an infiltrating growth pattern of pleomorphic astrocytes with diffuse positivity for glial fibrillary acidic protein. A couple of months later he presented at our institution with ascites and an anterior peritoneal mass. Repeat cerebrospinal fluid cytology and fine needle aspiration of the mass confirmed disseminated gliomatosis. Cytologic characteristics included clusters of anaplastic cells of variable size, high nuclear to cytoplasm ratio and scant to moderate cytoplasm. Occasional single bizarre multinucleated cells were seen with eccentric "partial wreath-like" nuclei, clumped chromatin and prominent nucleoli. Patient expired 13 months after initial presentation. Conclusion Disseminated primary diffuse leptomeningeal gliomatosis should be considered in the differential diagnosis of chronic aseptic meningitis and in the presence of a peritoneal tumor in patients with ventriculoperitoneal shunts. Immunocytochemistry may be of diagnostic value.

  6. Biocomputing: numerical simulation of glioblastoma growth using diffusion tensor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bondiau, Pierre-Yves [Institut National de Recherche en Informatique et Automatique, 2004 Route des Lucioles, 06 902 Sophia Antipolis (France); Clatz, Olivier [Institut National de Recherche en Informatique et Automatique, 2004 Route des Lucioles, 06 902 Sophia Antipolis (France); Sermesant, Maxime [Institut National de Recherche en Informatique et Automatique, 2004 Route des Lucioles, 06 902 Sophia Antipolis (France); Marcy, Pierre-Yves [Departement de Radiotherapie, Centre Antoine Lacassagne, 33 av de Valombrose, 06189 Nice (France); Delingette, Herve [Institut National de Recherche en Informatique et Automatique, 2004 Route des Lucioles, 06 902 Sophia Antipolis (France); Frenay, Marc [Departement d' Oncologie Medicale, Centre Antoine Lacassagne, 33 av de Valombrose, 06189 Nice (France); Ayache, Nicholas [Institut National de Recherche en Informatique et Automatique, 2004 Route des Lucioles, 06 902 Sophia Antipolis (France)

    2008-02-21

    Glioblastoma multiforma (GBM) is one of the most aggressive tumors of the central nervous system. It can be represented by two components: a proliferative component with a mass effect on brain structures and an invasive component. GBM has a distinct pattern of spread showing a preferential growth in the white fiber direction for the invasive component. By using the architecture of white matter fibers, we propose a new model to simulate the growth of GBM. This architecture is estimated by diffusion tensor imaging in order to determine the preferred direction for the diffusion component. It is then coupled with a mechanical component. To set up our growth model, we make a brain atlas including brain structures with a distinct response to tumor aggressiveness, white fiber diffusion tensor information and elasticity. In this atlas, we introduce a virtual GBM with a mechanical component coupled with a diffusion component. These two components are complementary, and can be tuned independently. Then, we tune the parameter set of our model with an MRI patient. We have compared simulated growth (initialized with the MRI patient) with observed growth six months later. The average and the odd ratio of image difference between observed and simulated images are computed. Displacements of reference points are compared to those simulated by the model. The results of our simulation have shown a good correlation with tumor growth, as observed on an MRI patient. Different tumor aggressiveness can also be simulated by tuning additional parameters. This work has demonstrated that modeling the complex behavior of brain tumors is feasible and will account for further validation of this new conceptual approach.

  7. Renal water molecular diffusion characteristics in healthy native kidneys: assessment with diffusion tensor MR imaging.

    Directory of Open Access Journals (Sweden)

    Zhenfeng Zheng

    Full Text Available BACKGROUND: To explore the characteristics of diffusion tensor imaging (DTI and magnetic resonance (MR imaging in healthy native kidneys. METHODS: Seventy-three patients without chronic kidney disease underwent DTI-MRI with spin echo-echo planar (SE-EPI sequences accompanied by an array spatial sensitivity encoding technique (ASSET. Cortical and medullary mean, axial and radial diffusivity (MD, AD and RD, fractional anisotropy (FA and primary, secondary and tertiary eigenvalues (λ1, λ2, λ3 were analysed in both kidneys and in different genders. RESULTS: Cortical MD, λ2, λ3, and RD values were higher than corresponding medullary values. The cortical FA value was lower than the medullary FA value. Medullary λ1 and RD values in the left kidney were lower than in the right kidney. Medullary λ2, and λ3 values in women were higher than those in men. Medullary FA values in women were lower than those in men. Medullary FA (r = 0.351, P = 0.002 and λ1 (r = 0.277, P = 0.018 positively correlated with eGFR. Medullary FA (r = -0.25, P = 0.033 negatively correlated with age. CONCLUSIONS: Renal water molecular diffusion differences exist in human kidneys and genders. Age and eGFR correlate with medullary FA and primary eigenvalue.

  8. Imaging of the brain, including diffusion-weighted imaging in methylmalonic acidemia

    Energy Technology Data Exchange (ETDEWEB)

    Michel, Steven J.; Given, Curtis A. [Department of Diagnostic Radiology, University of Kentucky Chandler Medical Center, Room HX-311C, 800 Rose Street, Lexington, KY 40536 (United States); Robertson, William C. [Department of Pediatric Neurology, University of Kentucky Chandler Medical Center, 800 Rose Street, Lexington, KY 40536 (United States)

    2004-07-01

    Methylmalonic acidemia (MMA) is a multifactorial autosomal recessive inborn error of organic acid metabolism, often presenting with neurologic findings. We report the imaging findings in a case of a child with classic neurological and laboratory findings for MMA. Imaging studies demonstrated abnormalities within the basal ganglia, particularly the globi pallidi (GP). Diffusion-weighted abnormalities seen in patients with MMA during an acute episode of metabolic acidosis and at follow-up are discussed. The authors are aware of only one prior report of serial examinations demonstrating resolution of restricted diffusion in the GP. The biochemical and pathophysiologic basis of the imaging findings of MMA are explained. (orig.)

  9. Quantitative evaluation of brain involvement in ataxia telangiectasia by diffusion weighted MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Firat, Ahmet Kemal [Inonu University Medical Faculty, Turgut Ozal Medical Center, Department of Radiology, Malatya 44280 (Turkey); Karakas, Hakki Muammer [Inonu University Medical Faculty, Turgut Ozal Medical Center, Department of Radiology, Malatya 44280 (Turkey)]. E-mail: hkarakas@inonu.edu.tr; Firat, Yezdan [Inonu University Medical Faculty, Turgut Ozal Medical Center, Department of Otorhinolaryngology, Malatya (Turkey); Yakinci, Cengiz [Inonu University Medical Faculty, Turgut Ozal Medical Center, Department of Pediatrics, Malatya (Turkey)

    2005-11-01

    Objective: To evaluate the value of diffusion weighted imaging (DWI) in diagnosing ataxia telangiectasia (AT) and to investigate the spatial distribution of cerebral microstructural changes caused by the disease. Methods: Six AT patients (9-13 years) and nine healthy control subjects were examined on 1.5 T scanner. In addition to conventional MR images, DWI were performed with a fat suppressed, multishot spin echo EPI sequence using B values of 0, 500 and 1000 s/mm{sup 2}. Mean ADC values were measured from 16 different supra and infratentorial location. The difference between controls and AT patients regarding ADC values, and the accuracy, sensitivity and specificity of them in discrimination were analyzed with t-tests, logistic regression analysis, ANOVA and ROC curves. Results: Conventional images of the controls were normal. In AT patients, the only conventional MR abnormality was cerebellar atrophy. The difference between both groups regarding mean ADC values was not significant for any of the cerebral structures. In contrary to cerebrum, cerebellar mean ADC values of patients and controls were statistically different (p < 0.011-0.0001). Patients and controls were classified with 100% accuracy using ADC values of cerebellar white matter and cortex together (p < 0.016). The cut-off ADC value (0.699 mm{sup 2}/s) for middle cerebellar cortex had produced highest (100%) sensitivity and specificity. There was a difference between superior, middle and inferior cerebellar cortex regarding ADC values (p < 0.026). Superior cerebellar cortex (0.987 {+-} 0.1956 mm{sup 2}/s) had higher ADC values than the middle and inferior cerebellar cortex. Conclusion: DWI provides a supplementary and objective imaging finding in AT. This finding is highly accurate in the radiological discrimination of healthy subjects and AT. Our findings also implicate that AT causes a diffuse atrophy and mostly affects superior part of the cortex.

  10. Diffusion Tensor Imaging in Rat Spinal Cord In-Vivo

    Science.gov (United States)

    Al-Rekabi, Zeinab

    2008-05-01

    Diffusion Tensor Imaging (DTI), an MRI technique based on probing the structure of tissues at a microscopic level is used to determine regional values of Fractional Anisotropy (FA) and mean diffusivity (Dav) of excised and in-vivo rat spinal cords. Two pulse sequences: Spin Echo (SE) and Echo Planar Imaging (EPI) are optimized to provide the best image quality, signal-to-noise ratio (SNR) and the greatest spatial resolution at reasonable acquisition times in the rat spinal cord. The study was conducted using a 7T BRUKER BioSpec MRI animal scanner. In the ex-vivo experiments images with the spatial resolution of 100 μm and the SNR of 1.938 ± 0.010 were acquired in 2 minutes. After optimization both methods were applied in-vivo. The values of FA and Dav acquired in this study showed good correlation with the literature values. Furthermore, results from these studies should provide the necessary baseline data for serial DTI in injured spinal cord in future studies.

  11. White Matter Degeneration with Aging: Longitudinal Diffusion MR Imaging Analysis.

    Science.gov (United States)

    de Groot, Marius; Cremers, Lotte G M; Ikram, M Arfan; Hofman, Albert; Krestin, Gabriel P; van der Lugt, Aad; Niessen, Wiro J; Vernooij, Meike W

    2016-05-01

    To determine longitudinally the rate of change in diffusion-tensor imaging (DTI) parameters of white matter microstructure with aging and to investigate whether cardiovascular risk factors influence this longitudinal change. This prospective population-based cohort study was approved by a dedicated ethics committee overseen by the national government, and all participants gave written informed consent. Community-dwelling participants without dementia were examined by using a research-dedicated 1.5-T magnetic resonance (MR) imager on two separate visits that were, on average, 2.0 years apart. Among 810 persons who were eligible for imaging at baseline, longitudinal imaging data were available for 501 persons (mean age, 69.9 years; age range, 64.1-91.1 years). Changes in normal-appearing white matter DTI characteristics in the tract centers were analyzed globally to investigate diffuse patterns of change and then locally by using voxelwise multilinear regression. The influence of cardiovascular risk factors was assessed by treating them as additional determinants in both analyses. Over the 2.0-year follow-up interval, global fractional anisotropy (FA) decreased by 0.0042 (P aging, with relative sparing of sensorimotor fibers. (©) RSNA, 2015 Online supplemental material is available for this article.

  12. Image quality assessment in panoramic dental radiography: a comparative study between conventional and digital systems.

    Science.gov (United States)

    Sabarudin, Akmal; Tiau, Yu Jin

    2013-02-01

    This study is designed to compare and evaluate the diagnostic image quality of dental panoramic radiography between conventional and digital systems. Fifty-four panoramic images were collected and divided into three groups consisting of conventional, digital with and without post processing image. Each image was printed out and scored subjectively by two experienced dentists who were blinded to the exposure parameters and system protocols. The evaluation covers of anatomical coverage and structures, density and image contrast. The overall image quality score revealed that digital panoramic with post-processing scored the highest of 3.45±0.19, followed by digital panoramic system without post-processing and conventional panoramic system with corresponding scores of 3.33±0.33 and 2.06±0.40. In conclusion, images produced by digital panoramic system are better in diagnostic image quality than that from conventional panoramic system. Digital post-processing visualization can improve diagnostic quality significantly in terms of radiographic density and contrast.

  13. Assessment of calf muscle contraction by diffusion tensor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Deux, J.F.; Luciani, A.; Zerbib, P.; Kobeiter, H.; Rahmouni, A. [Centre Hospitalo-Universitaire H. Mondor, Assistance Publique-Hopitaux de Paris, Service d' Imagerie Medicale, Creteil (France); Malzy, P. [Centre Hospitalo-Universitaire Lariboisiere, Assistance Publique-Hopitaux de Paris, Service d' Imagerie Medicale, Paris (France); Paragios, N. [Ecole Centrale de Paris, Chatenay Malabris (France); Bassez, G. [Centre Hospitalo-Universitaire H. Mondor, Assistance Publique-Hopitaux de Paris, Service des Maladies Neuro-Musculaires, Creteil (France); Roudot-Thoraval, F. [Centre Hospitalo-Universitaire H. Mondor, Assistance Publique-Hopitaux de Paris, Centre d' Investigation Clinique, Creteil (France); Vignaud, A. [Siemens Medical Division, Paris (France)

    2008-10-15

    The goal of this study was to assess the changes of water diffusion during contraction and elongation of calf muscles using diffusion tensor (DT) MRI in normal volunteers. Twenty volunteers (mean age, 29 {+-} 4 years) underwent DT MRI examination of the right calf. Echo planar imaging sequence was performed at rest, during dorsal flexion and during plantar flexion. The three eigenvalues ({lambda}1, {lambda}2, and {lambda}3), apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of the diffusion tensor were calculated for medial gastrocnemius (mGM) and tibialis anterior (TA). A fiber tractography was performed on both muscles. Non-parametric Wilcoxon and Mann Whitney tests were used for statistical evaluation. At rest, {lambda}1, {lambda}2 and ADC of mGM were higher than their counterparts of TA (P < 0.01). During dorsal flexion, the three eigenvalues and ADC of TA significantly increased (P < 0.05) as their counterparts of mGM slightly decreased (P=NS). Opposite variations were detected during plantar flexion of the foot. Visual analysis evidenced a relationship between 3D representations of MRI fibers and physiological state of muscles. Contraction of calf muscles produces changes in DT parameters, which are related to the physiological state of the muscle. (orig.)

  14. Atlas-based diffusion tensor imaging correlates of executive function

    Science.gov (United States)

    Nowrangi, Milap A.; Okonkwo, Ozioma; Lyketsos, Constantine; Oishi, Kenichi; Mori, Susumu; Albert, Marilyn; Mielke, Michelle M.

    2015-01-01

    Impairment in executive function (EF) is commonly found in Alzheimer’s Dementia (AD) and Mild Cognitive Impairment (MCI). Atlas-based Diffusion Tensor Imaging (DTI) methods may be useful in relating regional integrity to EF measures in MCI and AD. 66 participants (25 NC, 22 MCI, and 19 AD) received DTI scans and clinical evaluation. DTI scans were applied to a pre-segmented atlas and fractional anisotropy (FA) and mean diffusivity (MD) were calculated. ANOVA was used to assess group differences in frontal, parietal, and cerebellar regions. For regions differing between groups (p<0.01), linear regression examined the relationship between EF scores and regional FA and MD. Anisotropy and diffusivity in frontal and parietal lobe white matter (WM) structures were associated with EF scores in MCI and only frontal lobe structures in AD. EF was more strongly associated with FA than MD. The relationship between EF and anisotropy and diffusivity was strongest in MCI. These results suggest that regional WM integrity is compromised in MCI and AD and that FA may be a better correlate of EF than MD. PMID:25318544

  15. Comparison of radiographic measurements obtained with conventional an indirect digital imaging during endontic treatment

    Directory of Open Access Journals (Sweden)

    Ligia Buloto Schmitd

    2008-04-01

    Full Text Available The aims of this study were to evaluate the quality of indirect digitized radiographic images taken during endodontic procedures and to compare the measurements recorded with this technique to those obtained from conventional radiographs. Two-hundred conventional periapical radiographs taken at the undergraduate Endodontics Clinic of the Dental School of Bauru were digitized. The conventional and indirect digitized images were compared by three examiners as to the quality and accuracy of the measurements recorded during endodontic treatment, in canal length determination, gutta-percha adaptation, lateral condensation and final obturation. The conventional radiographs were observed on a film viewer, surrounded by a dark card, and measured with magnifying glass and a millimeter ruler; the indirect digitized images were evaluated on the Digora® for Windows software, with free utilization of the bright/contrast tool. Unlike the conventional radiographic images, all indirect digitized images were considered as having a high quality. The distance between the filling material and the root apex was 0.117 mm larger, on average, for the Digora® system (p<0.01. The measurements achieved by the investigated radiographic methods were clinically similar and they are thus equivalent. Changes in brightness and contrast of the images using Digora®software improved the diagnosis.

  16. COMPARISON OF RADIOGRAPHIC MEASUREMENTS OBTAINED WITH CONVENTIONAL AND INDIRECT DIGITAL IMAGING DURING ENDODONTIC TREATMENT

    Science.gov (United States)

    Schmitd, Ligia Buloto; Lima, Tatiana de Castro; Chinellato, Luiz Eduardo Montenegro; Bramante, Clóvis Monteiro; Garcia, Roberto Brandão; de Moraes, Ivaldo Gomes; Bernardineli, Norberti

    2008-01-01

    The aims of this study were to evaluate the quality of indirect digitized radiographic images taken during endodontic procedures and to compare the measurements recorded with this technique to those obtained from conventional radiographs. Two-hundred conventional periapical radiographs taken at the undergraduate Endodontics Clinic of the Dental School of Bauru were digitized. The conventional and indirect digitized images were compared by three examiners as to the quality and accuracy of the measurements recorded during endodontic treatment, in canal length determination, gutta-percha adaptation, lateral condensation and final obturation. The conventional radiographs were observed on a film viewer, surrounded by a dark card, and measured with magnifying glass and a millimeter ruler; the indirect digitized images were evaluated on the Digora® for Windows software, with free utilization of the bright/contrast tool. Unlike the conventional radiographic images, all indirect digitized images were considered as having a high quality. The distance between the filling material and the root apex was 0.117 mm larger, on average, for the Digora® system (p<0.01). The measurements achieved by the investigated radiographic methods were clinically similar and they are thus equivalent. Changes in brightness and contrast of the images using Digora® software improved the diagnosis. PMID:19089211

  17. Diffusion tensor imaging in medial temporal lobe epilepsy

    Institute of Scientific and Technical Information of China (English)

    YU Ai-hong; LI Kun-cheng; YU Chun-shui; WANG Yu-ping; XUE Su-fang

    2006-01-01

    Background Diffusion tensor imaging (DTI) is a noninvasive imaging technique for the assessment of theintegrity of cerebral tissues. This study was undertaken to assess the changes of diffusion indices of hippocampalformation (HF) in patients with medial temporal lobe epilepsy (MTLE).Methods Fourteen patients with MTLE and 14 healthy subjects were evaluated. Mean diffusivity (MD) andfractional anisotropy (FA) from the symmetrical-voxel sampling regions of the anterior HF were calculated in allsubjects. The MD and FA values were compared across the groups.Results No significant differences of MD and FA values were noted between right and left HF in the controls.In the patient group, MD significantly increased in the HF ipsilateral to the lesioned side [(9.27±1.09)×10-4mm2/s], compared with the values in the contralateral HF [(8.20±0.59)×10-4 mm2/s] (t = 4.479, P = 0.001) andhealthy subjects [(7.58±0.51)×10-4 mm2/s] (P<0.001), but no significant differences were found in FA. Whencompared with the controls, patients had a significantly higher MD inthe contralateral HF (P<0.05), but thedifference in FA was not statistically significant.Conclusions DTI could detect hippocampal abnormality in patients with MTLE. This technique may be helpfulfor preoperative evaluation of such patients.

  18. Correlation of proton MR spectroscopy and diffusion tensor imaging.

    Science.gov (United States)

    Irwan, Roy; Sijens, Paul E; Potze, Jan-Hendrik; Oudkerk, Matthijs

    2005-10-01

    Proton magnetic resonance spectroscopy ((1)H-MRS) provides indices of neuronal damage. Diffusion tensor imaging (DTI) relates to water diffusivity and fiber tract orientation. A method to compare (1)H-MRS and DTI findings was developed, tested on phantom and applied on normal brain. Point-resolved spectroscopy (T(R)/T(E)=1500/135) was used for chemical shift imaging of a supraventricular volume of interest of 8 x 8 x 2 cm(3) (64 voxels). In DTI, a segmental spin-echo sequence (T(R)/T(E)=5500/91) was used and slices were stacked to reproduce the slab used in MRS. The spatial distributions of choline and N-acetylaspartate (NAA) correlated to mean fractional anisotropy and apparent diffusion coefficient (ADC) for the inner 6 x 6=36 voxels defined in MRS, most notably NAA and ADC value (r=-.70, P<.00001; correlation across four subjects, 144 data pairs). This is the first association of neuron metabolite contents in volunteers with structure as indicated by DTI.

  19. Role of PROPELLER diffusion-weighted imaging and apparent diffusion coefficient in the evaluation of pituitary adenomas

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoud, Omar M. [Department of Neurosurgery, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551 (Japan); Department of Radiology, South Egypt Cancer Institute, Assiut University, Assiut 71515 (Egypt); Tominaga, Atsushi [Department of Neurosurgery, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551 (Japan); Amatya, Vishwa Jeet [Department of Pathology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8551 (Japan); Ohtaki, Megu [Department of Environmetrics and Biometrics, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8551 (Japan); Sugiyama, Kazuhiko; Sakoguchi, Tetsuhiko; Kinoshita, Yasuyuki [Department of Neurosurgery, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551 (Japan); Takeshima, Yukio [Department of Pathology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8551 (Japan); Abe, Nobukazu; Akiyama, Yuji [Department of Clinical Radiology, Hiroshima University Hospital, Hiroshima 734-8551 (Japan); El-Ghoriany, Ahmad I. [Department of Neurosurgery, Faculty of Medicine, Assiut University, Assiut 71515 (Egypt); Alla, Abdel Karim H. Abd; El-Sharkawy, Mostafa A.M. [Department of Radiology, Faculty of Medicine, Assiut University, Assiut 71515 (Egypt); Arita, Kazunori [Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima (Japan); Kurisu, Kaoru [Department of Neurosurgery, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551 (Japan); Yamasaki, Fumiyuki, E-mail: fyama@hiroshima-u.ac.jp [Department of Neurosurgery, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551 (Japan)

    2011-11-15

    Objective: The relationship between tumor consistency and apparent diffusion coefficient (ADC) values is controversial. We evaluated the role of the ADC using an advanced diffusion-weighted imaging (DWI) technique. We employed periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) DWI acquired on a 3-T magnetic resonance imaging (MRI) scanner to assess the consistency of pituitary adenomas and examined the relationship between the ADC and the hormone secretion status of the tumors and their MIB-1 labeling index (MIB-1 LI). Materials and methods: The study protocol was approved by our institutional review board. We retrospectively studied 24 operated patients with pituitary adenomas who had undergone PROPELLER DWI on a 3-T MRI scanner. Conventional MRI findings were expressed as the ratio of the signal intensity (SI) in the lesions to the SI of the normal white matter and the degree of contrast enhancement. Minimum-, mean-, and maximum ADC (ADC{sub min}, ADC{sub mean}, ADC{sub max}) values were calculated. The consistency of the tumors was determined by neurosurgeons. All surgical specimens were submitted for histological study to calculate the MIB-1 LI and the percent collagen content. Preoperative MRI-, intraoperative-, and histological findings were analyzed by a statistician. Results: Our study included 15 soft-, 5 fibrous-, and 4 hard tumors. Tumor consistency was strongly associated with the percent collagen content. However, neither the tumor consistency nor the percent collagen content was correlated with MRI findings or ADC values. The SI of growth hormone-producing adenomas on T2-WI was lower than of the other pituitary adenomas studied (p < 0.01); no other significant difference was found in the ADC or on conventional MRI between pituitary adenomas with different secretory functions. The MIB-1 LI of pituitary adenomas was not correlated with their appearance on conventional MRI or their ADC values. Conclusion: Using the

  20. Role of diffusion weighted imaging in musculoskeletal infections: Current perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Yogesh [Yale New Haven Health System at Bridgeport Hospital, Department of Radiology, Bridgeport, CT (United States); Khaleel, Mohammad [UT Southwestern Medical Center, Department of Orthopaedic Surgery, Dallas, TX (United States); Boothe, Ethan; Awdeh, Haitham [UT Southwestern Medical Center, Department of Radiology, Dallas, TX (United States); Wadhwa, Vibhor [University of Arkansas for Medical Sciences, Department of Radiology, Little Rock, AR (United States); Chhabra, Avneesh [UT Southwestern Medical Center, Department of Orthopaedic Surgery, Dallas, TX (United States); UT Southwestern Medical Center, Department of Radiology, Dallas, TX (United States)

    2017-01-15

    Accurate diagnosis and prompt therapy of musculoskeletal infections are important prognostic factors. In most cases, clinical history, examination and laboratory findings help one make the diagnosis, and routine magnetic resonance imaging (MRI) is useful to identify the extent of the disease process. However, in many situations, a routine MRI may not be specific enough especially if the patient cannot receive contrast intravenously, thereby delaying the appropriate treatment. Diffusion-weighted imaging (DWI) can help in many such situations by providing additional information, accurate characterization and defining the extent of the disease, so that prompt treatment can be initiated. In this article, we illustrate the imaging findings of the spectrum of musculoskeletal infections, emphasizing the role of DWI in this domain. (orig.)

  1. Comparative effects of Facebook and conventional media on body image dissatisfaction

    OpenAIRE

    Cohen, Rachel; Blaszczynski, Alex

    2015-01-01

    Background Appearance comparison has consistently been shown to engender body image dissatisfaction. To date, most studies have demonstrated this relationship between appearance comparison and body image dissatisfaction in the context of conventional media images depicting the thin-ideal. Social comparison theory posits that people are more likely to compare themselves to similar others. Since social media forums such as Facebook involve one’s peers, the current study aimed to determine wheth...

  2. Diffusion tensor imaging of white and grey matter within the spinal cord of normal Beagle dogs: Sub-regional differences of the various diffusion parameters.

    Science.gov (United States)

    Yoon, Hakyoung; Park, Noh-Won; Ha, Yun-Mi; Kim, Jaehwan; Moon, Won-Jin; Eom, Kidong

    2016-09-01

    Diffusion tensor imaging (DTI) is an advanced diffusion weighted imaging technique that can identify early stage lesions and Wallerian degeneration within the spinal cord; these changes are difficult to recognise on conventional magnetic resonance imaging (MRI). The only DTI parameters previously investigated in dogs are fractional anisotropy and mean diffusivity (MD). The aim of this study was to evaluate multiple DTI parameters in sub-regional areas of the spinal cord in normal Beagles. All imaging data were obtained from the lumbar spinal cord (L1-L3) of ten normal dogs using a 3 Tesla MRI scanner. Transverse multi-shot echo planar imaging sequences (b values = 0 and 800 s/mm(2); 12 directions) were used for DTI. Regions of interest were selected from sub-regions of the white and grey matter, and from the whole spinal cord, in the transverse plane in all DTI maps. The DTI parameters in spinal cord sub-regions in the transverse plane were significantly different amongst the white matter, grey matter and whole spinal cord (P matter sub-regions (P grey matter may be useful for regional evaluation of the dog spinal cord.

  3. Diffusion-weighted imaging in neuroradiology; Diffusionsgewichtung in der Neuroradiologie

    Energy Technology Data Exchange (ETDEWEB)

    Schlamann, M. [Universitaetsklinikum Essen, Institut fuer Diagnostische und Interventionelle Radiologie und Neuroradiologie, Essen (Germany)

    2011-03-15

    Diffusion-weighted imaging is becoming increasingly more important in neuroradiology. Formerly this technique was mainly used in stroke diagnostics but the spectrum of applications is becoming increasingly larger. Diffusion-weighted imaging is a useful tool for differentiation between metastases and abscesses, for assessment of the depth of invasiveness of tumors and to differentiate inflammation from astrocytomas. It has now become a standard technique in multiple sclerosis imaging. A further advantage in addition to the diagnostic capabilities is the speed of the sequence which makes it insensitive to movement artefacts. (orig.) [German] Die Diffusionsgewichtung erhaelt in der Neuroradiologie einen immer hoeheren Stellenwert. War sie frueher hauptsaechlich in der Schlaganfalldiagnostik verbreitet, erweitert sich das Anwendungsspektrum immer mehr. Die Diffusionsgewichtung ist sowohl ein hilfreiches Werkzeug zur Differenzierung zwischen Metastasen und Abszessen als auch zur Beurteilung der Invasionstiefe von Tumoren oder zur Unterscheidung von Entzuendungen und Astrozytomen. Sie gehoert mittlerweile zum Standard in der MS-Bildgebung. Ein weiterer Vorteil neben der diagnostischen Aussagekraft ist die Schnelligkeit der Sequenz, die damit sehr unempfindlich gegenueber Bewegungsartefakten ist. (orig.)

  4. DIAGNOSTIC VALUE OF INTERICTAL DIFFUSION-WEIGHTED IMAGING IN EVALUATION OF INTRACTABLE TEMPORAL LOBE EPILEPSY

    Institute of Scientific and Technical Information of China (English)

    Rui Wang; Saying-Li; Min Chen; Cheng Zhou

    2008-01-01

    Objective To explore the ability of interictal diffusion-weighted imaging (DWI) to localize the temporal lobe of seizure origin and to predict postoperative seizure control in patients with temporal lobe epilepsy (TLE).Methods Twenty-seven patients with intractable TLE considered for surgery and 19 healthy volunteers were studied with conventional magnetic resonance imaging (MRI) and DWL Apparent diffusion coefficients (ADCs) of bilateral hippocampi in both TLE patients and control subjects were obtained. Lateralization to either temporal lobe with hippoeampal ADC was based on the threshold values derived from ± 1 SD of fight/left ratios in normal subjects. And the postoperative pathology was reviewed.Results Hippocampal ADCs were higher on the side of surgery compared with those on the contralateral side as well as the ipsilateral side in control subjects [ resected side ( 109. 8±7.3 ) × 10-5 cm2/s, contralateral side (91.7±4. 7) × 10-5 cm2/s, control subjects (81.6±5.2) × 10-5 cm2/s, all P 0.05 ).Conclusions Conventional MRI is a sensitive method to detect hippocampal sclerosis. Accuracy of the right/left hip-pocampal ADC ratio for lateralizing to the side of surgery is very high, but it isn't a better predictor of surgical outcome.

  5. Diffusion tensor imaging in inflammatory and neoplastic intramedullary spinal cord lesions: Focusing on fiber tracking

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyo Jin; Lee, Joon Woo; Lee, Eugene; Kim, Sung Gon; Kang, Yu Suhn; Ahn, Joong Mo; Kang, Heung Sik [Dept. of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of)

    2017-02-15

    Inflammatory and neoplastic intramedullary spinal cord lesions have overlapping clinical features, and it is occasionally difficult to distinguish one from the other on conventional magnetic resonance imaging. We aimed to compare diffusion tensor imaging findings between inflammatory and neoplastic intramedullary spinal cord lesions, with a specific focus on patterns of fiber tracking. Diffusion tensor imaging was performed in patients with either inflammatory or neoplastic intramedullary spinal cord lesions. The fiber tracking patterns (categorized as “intact,” “displaced,” or “interrupted”) were compared between these two groups. Eight patients were included in the study: 5 patients with pathologically or clinically confirmed inflammatory lesions and 3 patients with pathologically or clinically confirmed neoplastic lesions. Among the 5 patients with inflammatory lesions, 2 patients exhibited the displaced pattern and 3 patients exhibited the intact pattern. Among the 3 patients with neoplastic lesions, 1 patient exhibited the intact pattern, 1 patient exhibited the displaced pattern, and 1 patient exhibited the interrupted pattern. In this study, inflammatory and neoplastic intramedullary spinal cord lesions were not clearly differentiated by fiber tracking; both conditions can present with overlapping features such as displaced fibers. The exclusion of inflammatory conditions based on the presence of displaced fibers in fiber tracking images should be avoided.

  6. Interrogation of living myocardium in multiple static deformation states with diffusion tensor and diffusion spectrum imaging.

    Science.gov (United States)

    Lohezic, Maelene; Teh, Irvin; Bollensdorff, Christian; Peyronnet, Rémi; Hales, Patrick W; Grau, Vicente; Kohl, Peter; Schneider, Jürgen E

    2014-08-01

    Diffusion tensor magnetic resonance imaging (MRI) reveals valuable insights into tissue histo-anatomy and microstructure, and has steadily gained traction in the cardiac community. Its wider use in small animal cardiac imaging in vivo has been constrained by its extreme sensitivity to motion, exaggerated by the high heart rates usually seen in rodents. Imaging of the isolated heart eliminates respiratory motion and, if conducted on arrested hearts, cardiac pulsation. This serves as an important intermediate step for basic and translational studies. However, investigating the micro-structural basis of cardiac deformation in the same heart requires observations in different deformation states. Here, we illustrate the imaging of isolated rat hearts in three mechanical states mimicking diastole (cardioplegic arrest), left-ventricular (LV) volume overload (cardioplegic arrest plus LV balloon inflation), and peak systole (lithium-induced contracture). An optimised MRI-compatible Langendorff perfusion setup with the radio-frequency (RF) coil integrated into the wet chamber was developed for use in a 9.4T horizontal bore scanner. Signal-to-noise ratio improved significantly, by 75% compared to a previous design with external RF coil, and stability tests showed no significant changes in mean T1, T2 or LV wall thickness over a 170 min period. In contracture, we observed a significant reduction in mean fractional anisotropy from 0.32 ± 0.02 to 0.28 ± 0.02, as well as a significant rightward shift in helix angles with a decrease in the proportion of left-handed fibres, as referring to the locally prevailing cell orientation in the heart, from 24.9% to 23.3%, and an increase in the proportion of right-handed fibres from 25.5% to 28.4%. LV overload, in contrast, gave rise to a decrease in the proportion of left-handed fibres from 24.9% to 21.4% and an increase in the proportion of right-handed fibres from 25.5% to 26.0%. The modified perfusion and coil setup offers

  7. Diffusion-weighted MR imaging of thyroid nodules

    Energy Technology Data Exchange (ETDEWEB)

    Bozgeyik, Zulkif; Coskun, Sonay; Ogur, Erkin [Firat University, Department of Radiology, Faculty of Medicine, Elazig (Turkey); Dagli, A.F. [Firat University, Department of Pathology, Faculty of Medicine, Elazig (Turkey); Ozkan, Yusuf; Sahpaz, Fatih [Firat University, Department of Internal Medicine, Faculty of Medicine, Elazig (Turkey)

    2009-03-15

    The purpose of our study was to determine the diagnostic role of diffusion-weighted imaging (DWI) in the differentiating of malignant and benign thyroid nodules by using fine needle aspiration biopsy cytology criteria as a reference standard. The apparent diffusion coefficient (ADC) values of the normal-looking thyroid parenchyma were also evaluated both in normal patients and in patients with nodules. Between March 2007 and February 2008, 76 consecutive patients with ultrasound-diagnosed thyroid nodules and 20 healthy subjects underwent diffusion-weighted MR imaging by using single-shot spin echo, echo planar imaging. A total of 93 nodules were included in the study using the following b factors 100, 200, and 300 mm{sup 2}/s. ADC values of thyroid nodules and normal area in all subjects were calculated and compared using suitable statistical analysis. Mean ADC values for malignant and benign nodules were 0.96{+-}0.65 x 10{sup -3} and 3.06{+-}0.71 x 10{sup -3} mm{sup 2}/s. for b-300 factor, 0.56{+-}0.43 x 10{sup -3} and 1.80{+-}0.60 x 10{sup -3} mm{sup 2}/s for b-200, and 0.30{+-}0.20 x 10{sup -3} and 1.15{+-}0.43 x 10{sup -3}mm{sup 2}/s, for b-300, respectively. Mean ADC values of malignant nodules were lower than benign nodules. There were significant differences in ADC values between benign and malignant nodules. ADC values among normal-appearing thyroid parenchyma of patients and normal-appearing thyroid parenchyma of healthy subjects were insignificant at all b factors. Benign nodules have higher ADC values than malignant ones. DWI may be helpful in differentiating malign and benign thyroid nodules. (orig.)

  8. Diffusion tensor imaging in neuropsychiatric systemic lupus erythematosus

    Directory of Open Access Journals (Sweden)

    Qualls Clifford R

    2010-07-01

    Full Text Available Abstract Background Neuropsychiatric systemic lupus erythematosus (NPSLE is associated with increased morbidity and mortality. Methods We used Diffusion Tensor Imaging (DTI to assess white matter abnormalities in seventeen NPSLE patients, sixteen SLE patients without NPSLE, and twenty age- and gender-matched controls. Results NPSLE patients differed significantly from SLE and control patients in white matter integrity of the body of the corpus callosum, the left arm of the forceps major and the left anterior corona radiata. Conclusions Several possible mechanisms of white matter injury are explored, including vascular injury, medication effects, and platelet or fibrin macro- or microembolism from Libman-Sacks endocarditis.

  9. Digital volume imaging of the PEFC gas diffusion layer

    Energy Technology Data Exchange (ETDEWEB)

    Borup, Rodney L [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Mukherjee, Partha [ORNL; Shim, Eunkyoung [NC ST

    2010-01-01

    The gas diffusion layer (GDL) plays a key role in the overall performance/durability of a polymer electrolyte fuel cell (PEFC). Of profound importance, especially in the context of water management and flooding phenomena, is the influence of the underlying pore morphology and wetting characteristics Of the GDL microstructure. In this article, we present the digital volumetric imaging (DVI) technique in order to generate the 3-D carbon paper GDL microstructure. The internal pore structure and the local microstructural variations in terms of fiber alignment and fiber/binder distributions are investigated using the several 3-D thin sections of the sample obtained from DVI.

  10. Diffusion tensor imaging differences relate to memory deficits in diffuse traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Roig Teresa

    2011-02-01

    Full Text Available Abstract Background Memory is one of the most impaired functions after traumatic brain injury (TBI. We used diffusion tensor imaging (DTI to determine the structural basis of memory deficit. We correlated fractional anisotropy (FA of the fasciculi connecting the main cerebral regions that are involved in declarative and working memory functions. Methods Fifteen patients with severe and diffuse TBI and sixteen healthy controls matched by age and years of education were scanned. The neuropsychological assessment included: Letter-number sequencing test (LNS, 2-back task, digit span (forwards and backwards and the Rivermead profilet. DTI was analyzed by a tract-based spatial statics (TBSS approach. Results Whole brain DTI analysis showed a global decrease in FA values that correlated with the 2-back d-prime index, but not with the Rivermead profile. ROI analysis revealed positive correlations between working memory performance assessed by 2-back d-prime and superior longitudinal fasciculi, corpus callosum, arcuate fasciculi and fornix. Declarative memory assessed by the Rivermead profile scores correlated with the fornix and the corpus callosum. Conclusions Diffuse TBI is associated with a general decrease of white matter integrity. Nevertheless deficits in specific memory domains are related to different patterns of white matter damage.

  11. Diffusion-weighted imaging of the abdomen at 3.0 Tesla: image quality and apparent diffusion coefficient reproducibility compared with 1.5 Tesla.

    NARCIS (Netherlands)

    Rosenkrantz, A.B.; Oei, M.T.H.; Babb, J.S.; Niver, B.E.; Taouli, B.

    2011-01-01

    PURPOSE: To compare single-shot echo-planar imaging (SS EPI) diffusion-weighted MRI (DWI) of abdominal organs between 1.5 Tesla (T) and 3.0T in healthy volunteers in terms of image quality, apparent diffusion coefficient (ADC) values, and ADC reproducibility. MATERIALS AND METHODS: Eight healthy vol

  12. Diffusion-weighted imaging of the abdomen at 3.0 Tesla: image quality and apparent diffusion coefficient reproducibility compared with 1.5 Tesla.

    NARCIS (Netherlands)

    Rosenkrantz, A.B.; Oei, M.T.H.; Babb, J.S.; Niver, B.E.; Taouli, B.

    2011-01-01

    PURPOSE: To compare single-shot echo-planar imaging (SS EPI) diffusion-weighted MRI (DWI) of abdominal organs between 1.5 Tesla (T) and 3.0T in healthy volunteers in terms of image quality, apparent diffusion coefficient (ADC) values, and ADC reproducibility. MATERIALS AND METHODS: Eight healthy

  13. Diffusion-weighted imaging of the abdomen at 3.0 Tesla: image quality and apparent diffusion coefficient reproducibility compared with 1.5 Tesla.

    NARCIS (Netherlands)

    Rosenkrantz, A.B.; Oei, M.T.H.; Babb, J.S.; Niver, B.E.; Taouli, B.

    2011-01-01

    PURPOSE: To compare single-shot echo-planar imaging (SS EPI) diffusion-weighted MRI (DWI) of abdominal organs between 1.5 Tesla (T) and 3.0T in healthy volunteers in terms of image quality, apparent diffusion coefficient (ADC) values, and ADC reproducibility. MATERIALS AND METHODS: Eight healthy vol

  14. In vivo sectional imaging of the retinal periphery using conventional optical coherence tomography systems

    Directory of Open Access Journals (Sweden)

    Abhishek Kothari

    2012-01-01

    Full Text Available Optical coherence tomography (OCT has transformed macular disease practices. This report describes the use of conventional OCT systems for peripheral retinal imaging. Thirty-six eyes with peripheral retinal pathology underwent imaging with conventional OCT systems. In vivo sectional imaging of lattice degeneration, snail-track degeneration, and paving-stone degeneration was performed. Differences were noted between phenotypes of lattice degeneration. Several findings previously unreported in histopathology studies were encountered. Certain anatomic features were seen that could conceivably explain clinical and intraoperative behavior of peripheral lesions. Peripheral OCT imaging helped elucidate clinically ambiguous situations such as retinal breaks, subclinical retinal detachment, retinoschisis, choroidal nevus, and metastasis. Limitations of such scanning included end-gaze nystagmus and far peripheral lesions. This first of its kind study demonstrates the feasibility of peripheral retinal OCT imaging and expands the spectrum of indications for which OCT scanning may be clinically useful.

  15. Non-Gaussian diffusion imaging for enhanced contrast of brain tissue affected by ischemic stroke.

    Directory of Open Access Journals (Sweden)

    Farida Grinberg

    Full Text Available Recent diffusion MRI studies of stroke in humans and animals have shown that the quantitative parameters characterising the degree of non-Gaussianity of the diffusion process are much more sensitive to ischemic changes than the apparent diffusion coefficient (ADC considered so far as the "gold standard". The observed changes exceeded that of the ADC by a remarkable factor of 2 to 3. These studies were based on the novel non-Gaussian methods, such as diffusion kurtosis imaging (DKI and log-normal distribution function imaging (LNDFI. As shown in our previous work investigating the animal stroke model, a combined analysis using two methods, DKI and LNDFI provides valuable complimentary information. In the present work, we report the application of three non-Gaussian diffusion models to quantify the deviations from the Gaussian behaviour in stroke induced by transient middle cerebral artery occlusion in rat brains: the gamma-distribution function (GDF, the stretched exponential model (SEM, and the biexponential model. The main goal was to compare the sensitivity of various non-Gaussian metrics to ischemic changes and to investigate if a combined application of several models will provide added value in the assessment of stroke. We have shown that two models, GDF and SEM, exhibit a better performance than the conventional method and allow for a significantly enhanced visualization of lesions. Furthermore, we showed that valuable information regarding spatial properties of stroke lesions can be obtained. In particular, we observed a stratified cortex structure in the lesions that were well visible in the maps of the GDF and SEM metrics, but poorly distinguishable in the ADC-maps. Our results provided evidence that cortical layers tend to be differently affected by ischemic processes.

  16. Diffusion-weighted imaging of normal fibroglandular breast tissue : influence of microperfusion and fat suppression technique on the apparent diffusion coefficient

    NARCIS (Netherlands)

    Baron, Paul; Dorrius, Monique D.; Kappert, Peter; Oudkerk, Matthijs; Sijens, Paul E.

    2010-01-01

    The influence of microperfusion and fat suppression technique on the apparent diffusion coefficient (ADC) values obtained with diffusion weighted imaging (DWI) of normal fibroglandular breast tissue was investigated. Seven volunteers (14 breasts) were scanned using diffusion weighting factors (b val

  17. Use of Diffusion Spectrum imaging in preliminary longitudinal evaluation of Amyotrophic Lateral Sclerosis: development of an imaging biomarker

    Directory of Open Access Journals (Sweden)

    Kumar eAbhinav

    2014-04-01

    Full Text Available Previous diffusion tensor imaging (DTI studies have shown white matter pathology in ALS, predominantly in the motor pathways. Further these studies have shown that DTI can be used longitudinally to track pathology over time, making white matter pathology a candidate as an outcome measure in future trials. DTI has demonstrated application in group studies, however its derived indices, for example fractional anisotropy, are susceptible to partial volume effects, making its role questionable in examining individual progression. We hypothesize that changes in the white matter are present in ALS beyond the motor tracts, and that the affected pathways and associated pattern of disease progression can be tracked longitudinally using automated diffusion connectometry analysis. Connectometry analysis is based on diffusion spectrum imaging (DSI and overcomes the limitations of a conventional tractography approach and DTI. The identified affected white matter tracts can then be assessed in a targeted fashion using High definition fiber tractography (a novel white matter MR imaging technique. Changes in quantitative and qualitative markers over time could then be correlated with clinical progression.We illustrate these principles towards developing an imaging biomarker for demonstrating individual progression, by presenting results for five ALS patients, including with longitudinal data in two. Preliminary analysis demonstrated a number of changes bilaterally and asymmetrically in motoric and extramotoric white matter pathways. Further the limbic system was also affected possibly explaining the cognitive symptoms in ALS. In the two longitudinal subjects, the white matter changes were less extensive at baseline, although there was evidence of disease progression in a frontal pattern with a relatively spared postcentral gyrus, consistent with the known pathology in ALS.

  18. Preliminary study on diffuse axonal injury by Fourier transform infrared spectroscopy histopathology imaging.

    Science.gov (United States)

    Yang, Tiantong; He, Guanglong; Zhang, Xiang; Chang, Lin; Zhang, Haidong; Ripple, Mary G; Fowler, David R; Li, Ling

    2014-01-01

    The objective of this study was to evaluate the application of Fourier transform infrared (FTIR) spectroscopy for detecting diffuse axonal injury (DAI) in a mouse model. Brain tissues from DAI mouse model were prepared with H&E, silver, and β-amyloid precursor protein (β-APP) immunohistochemistry stains and were also studied with FTIR. The infrared spectrum images showed high absorption of amide II in the subcortical white matter of the experimental mouse brain, while there was no obvious expression of amide II in the control mouse brain. The areas with high absorption of amide II were in the same distribution as the DAI region confirmed by the silver and β-APP studies. The result suggests that high absorption of amide II correlates with axonal injury. The use of FTIR imaging allows the biochemical changes associated with DAI pathologies to be detected in the tissues, thus providing an important adjunct method to the current conventional pathological diagnostic techniques.

  19. Diffusion imaging changes in grey matter in Alzheimer's disease: a potential marker of early neurodegeneration.

    Science.gov (United States)

    Weston, Philip S J; Simpson, Ivor J A; Ryan, Natalie S; Ourselin, Sebastien; Fox, Nick C

    2015-01-01

    Alzheimer's disease (AD) is recognized to have a long presymptomatic period, during which there is progressive accumulation of molecular pathology, followed by inexorable neuronal damage. The ability to identify presymptomatic individuals with evidence of neurodegenerative change, to stage their disease, and to track progressive changes will be important for early diagnosis and for prevention trials. Despite recent advances, particularly in magnetic resonance imaging, our ability to identify early neurodegenerative changes reliably is limited. The development of diffusion-weighted magnetic resonance imaging, which is sensitive to microstructural changes not visible with conventional volumetric techniques, has led to a number of diffusion imaging studies in AD; these have largely focused on white matter changes. However, in AD cerebral grey matter is affected very early, with pathological studies suggesting that grey matter changes predate those in white matter. In this article we review the growing number of studies that assess grey matter diffusivity changes in AD. Although use of the technique is still at a relatively early stage, results so far have been promising. Initial studies identified changes in diffusion measures in the hippocampi of patients with mild cognitive impairment, which predated macroscopic volume loss, with positive predictive value for progression to AD dementia. More recent studies have identified abnormalities in multiple neocortical areas (particularly the posterior cingulate) at various stages of disease progression. Studies of patients who carry genetic mutations predisposing to autosomal dominant familial AD have shown cortical and subcortical grey matter diffusivity changes several years before the expected onset of the first clinical symptoms. The technique is not without potential methodological difficulties, especially relating to partial volume effects, although recent advances appear to be reducing such issues. Going forward

  20. Mathematical abilities in dyslexic children: a diffusion tensor imaging study.

    Science.gov (United States)

    Koerte, Inga K; Willems, Anna; Muehlmann, Marc; Moll, Kristina; Cornell, Sonia; Pixner, Silvia; Steffinger, Denise; Keeser, Daniel; Heinen, Florian; Kubicki, Marek; Shenton, Martha E; Ertl-Wagner, Birgit; Schulte-Körne, Gerd

    2016-09-01

    Dyslexia is characterized by a deficit in language processing which mainly affects word decoding and spelling skills. In addition, children with dyslexia also show problems in mathematics. However, for the latter, the underlying structural correlates have not been investigated. Sixteen children with dyslexia (mean age 9.8 years [0.39]) and 24 typically developing children (mean age 9.9 years [0.29]) group matched for age, gender, IQ, and handedness underwent 3 T MR diffusion tensor imaging as well as cognitive testing. Tract-Based Spatial Statistics were performed to correlate behavioral data with diffusion data. Children with dyslexia performed worse than controls in standardized verbal number tasks, such as arithmetic efficiency tests (addition, subtraction, multiplication, division). In contrast, the two groups did not differ in the nonverbal number line task. Arithmetic efficiency, representing the total score of the four arithmetic tasks, multiplication, and division, correlated with diffusion measures in widespread areas of the white matter, including bilateral superior and inferior longitudinal fasciculi in children with dyslexia compared to controls. Children with dyslexia demonstrated lower performance in verbal number tasks but performed similarly to controls in a nonverbal number task. Further, an association between verbal arithmetic efficiency and diffusion measures was demonstrated in widespread areas of the white matter suggesting compensatory mechanisms in children with dyslexia compared to controls. Taken together, poor fact retrieval in children with dyslexia is likely a consequence of deficits in the language system, which not only affects literacy skills but also impacts on arithmetic skills.

  1. Diffusion-weighted MR imaging in transient ischaemic attacks

    Energy Technology Data Exchange (ETDEWEB)

    Lamy, C.; Calvet, D.; Domigo, V.; Mas, J. [de l' Hopital Sainte-Anne, Service de Neurologie, Paris Cedex 14 (France); Oppenheim, C.; Naggara, O.; Meder, J.F. [Hoepital Sainte-Anne, Departement d' Imagere Morphologique et Fonchonnille, Paris (France)

    2006-05-15

    The purpose of this study was to determine frequency and the characteristics of diffusion-weighted imaging (DWI) abnormalities in patients with transient ischaemic attack (TIA). We analysed data of 98 consecutive patients (mean age: 60.6{+-}15.4 years, 56 men) admitted between January 2003 and April 2004 for TIA. Age, gender, symptom type and duration, delay from onset to magnetic resonance imaging (MRI), probable or possible TIA and cause of TIA were compared in patients with (DWI+) and without (DWI-) lesions on DWI. Volume and apparent diffusion coefficient (ADC) values of DWI lesions were computed. DWI revealed ischaemic lesions in 34 patients (34.7%). Lesions were small (mean volume: 1.9 cm{sup 3}{+-}3.3), and ADC was moderately decreased (mean ADC ratio: 79.5%). The diagnosis of TIA was considered as probable in all DWI+ patients. A multiple logistic regression model demonstrated that TIA duration greater than or equal to 60 min (OR, 7.6; 95% CI, 2.3-25.7), aphasia (OR, 9.2; 95% CI, 2.7-31.4) and motor deficit (OR, 5.1; 95% CI, 1.5-17.8) were independent predictors of DWI lesions. Prolonged TIA duration, aphasia and motor deficits are associated with DWI lesions. More than half of TIA patients with symptoms lasting more than 60 min have DWI lesions. (orig.)

  2. Characterization of benign and malignant solid breast masses: comparison of conventional US and tissue harmonic imaging.

    Science.gov (United States)

    Cha, Joo Hee; Moon, Woo Kyung; Cho, Nariya; Kim, Sun Mi; Park, Seong Ho; Han, Boo-Kyung; Choe, Yeon Hyeon; Park, Jeong Mi; Im, Jung-Gi

    2007-01-01

    To prospectively compare the diagnostic performance of radiologists by using conventional ultrasonography (US) and tissue harmonic imaging for the differentiation of benign from malignant solid breast masses, with histologic results used as the reference standard. The study was approved by the institutional review board, and informed consent was obtained from all patients. Images were obtained with conventional US and tissue harmonic imaging in 88 patients (age range, 25-67 years; mean age, 45 years) with 91 solid breast masses (30 cancers and 61 benign lesions) before excisional or needle biopsy. Three experienced radiologists, who did not perform the examinations, independently analyzed the US findings and provided a level of suspicion to indicate the probability of malignancy. Results were evaluated by using kappa statistics and receiver operating characteristic (ROC) analyses. Regarding the descriptions of US findings, echogenicity (kappa=0.205) was the most discordant between conventional US and tissue harmonic imaging, followed by margin (kappa=0.495), lesion boundary (kappa=0.495), calcifications (kappa=0.537), posterior acoustic transmission (kappa=0.546), echotexture (kappa=0.586), shape (kappa=0.591), and orientation (kappa=0.594). The area under the ROC curve (Az) for conventional US and tissue harmonic imaging was 0.84 and 0.79, respectively, for reader 1; 0.88 and 0.85, respectively, for reader 2; and 0.91 and 0.89, respectively, for reader 3. The overall Az value for the three readers was 0.88 for conventional US and 0.84 for tissue harmonic imaging (95% confidence interval: -0.0950, 0.1646; P=.595). The performance of the radiologists with respect to the characterization of solid breast masses as benign or malignant was not significantly improved with tissue harmonic imaging. Copyright (c) RSNA, 2006.

  3. Dual-phase cardiac diffusion tensor imaging with strain correction.

    Directory of Open Access Journals (Sweden)

    Christian T Stoeck

    Full Text Available In this work we present a dual-phase diffusion tensor imaging (DTI technique that incorporates a correction scheme for the cardiac material strain, based on 3D myocardial tagging.In vivo dual-phase cardiac DTI with a stimulated echo approach and 3D tagging was performed in 10 healthy volunteers. The time course of material strain was estimated from the tagging data and used to correct for strain effects in the diffusion weighted acquisition. Mean diffusivity, fractional anisotropy, helix, transverse and sheet angles were calculated and compared between systole and diastole, with and without strain correction. Data acquired at the systolic sweet spot, where the effects of strain are eliminated, served as a reference.The impact of strain correction on helix angle was small. However, large differences were observed in the transverse and sheet angle values, with and without strain correction. The standard deviation of systolic transverse angles was significantly reduced from 35.9±3.9° to 27.8°±3.5° (p<0.001 upon strain-correction indicating more coherent fiber tracks after correction. Myocyte aggregate structure was aligned more longitudinally in systole compared to diastole as reflected by an increased transmural range of helix angles (71.8°±3.9° systole vs. 55.6°±5.6°, p<0.001 diastole. While diastolic sheet angle histograms had dominant counts at high sheet angle values, systolic histograms showed lower sheet angle values indicating a reorientation of myocyte sheets during contraction.An approach for dual-phase cardiac DTI with correction for material strain has been successfully implemented. This technique allows assessing dynamic changes in myofiber architecture between systole and diastole, and emphasizes the need for strain correction when sheet architecture in the heart is imaged with a stimulated echo approach.

  4. Radiopacity of restorative composites by conventional radiography and digital images with different resolutions

    Energy Technology Data Exchange (ETDEWEB)

    Dantas, Raquel Venancio; Samento, Hugo Ramalho [Graduate Program in Dentistry, Federal University of Pelotas, Pelotas (Brazil); Duarte, Rosangela Marques; Raso, Sonia Saeger Meireles Monte; De Andrade Ana Karina Maciel; Anjos-Pontual Maria Luiza Dos [Dept. of Operative Dentistry, Federal University of Paraiba, Pelotas (Brazil)

    2013-09-15

    This study was performed to evaluate and compare the radiopacity of dentin, enamel, and 8 restorative composites on conventional radiograph and digital images with different resolutions. Specimens were fabricated from 8 materials and human molars were longitudinally sectioned 1.0 mm thick to include both enamel and dentin. The specimens and tooth sections were imaged by conventional radiograph using 4 sized intraoral film and digital images were taken in high speed and high resolution modes using a phosphor storage plate. Densitometric evaluation of the enamel, dentin, restorative materials, a lead sheet, and an aluminum step wedge was performed on the radiographic images. For the evaluation, the Al equivalent (mm) for each material was calculated. The data were analyzed using one-way ANOVA and Tukey's test (p<0.05), considering the material factor and then the radiographic method factor, individually. The high speed mode allowed the highest radiopacity, while the high resolution mode generated the lowest values. Furthermore, the high resolution mode was the most efficient method for radiographic differentiation between restorative composites and dentin. The conventional radiograph was the most effective in enabling differentiation between enamel and composites. The high speed mode was the least effective in enabling radiographic differentiation between the dental tissues and restorative composites. The high speed mode of digital imaging was not effective for differentiation between enamel and composites. This made it less effective than the high resolution mode and conventional radiographs. All of the composites evaluated showed radiopacity values that fit the ISO 4049 recommendations.

  5. Role of Diffusion Tensor MR Imaging in Degenerative Cervical Spine Disease: a Review of the Literature.

    Science.gov (United States)

    Banaszek, A; Bladowska, J; Podgórski, P; Sąsiadek, M J

    2016-09-01

    In the article we review the current role of diffusion tensor imaging (DTI), a modern magnetic resonance (MR) technique, in the diagnosis and the management of cervical spondylotic myelopathy (CSM), the most serious complication of degenerative cervical spine disease (DCSD). The pathogenesis of DCSD is presented first with an emphasis placed on the pathological processes leading to myelopathy development. An understanding of the pathophysiological background of DCSD is necessary for appropriate interpretation of MR images, both plain and DTI. Conventional MRI is currently the imaging modality of choice in DCSD and provides useful information concerning the extent of spondylotic changes and degree of central spinal canal stenosis; however its capability in myelopathy detection is limited. DTI is a state of the art imaging method which recently has emerged in spinal cord investigations and has the potential to detect microscopic alterations which are beyond the capability of plain MRI. In the article we present the physical principles underlying DTI which determine its sensitivity, followed by an overview of technical aspects of DTI acquisition with a special consideration of spinal cord imaging. Finally, the scientific reports concerning DTI utility in DSCD are also reviewed. DTI detects spinal cord injury in the course of DCSD earlier than any other method and could be useful in predicting surgical outcomes in CMS patients, however technical and methodology improvement as well as standardization of acquisition protocols and postprocessing methods among the imaging centers are needed before its implementation in clinical practice.

  6. In vivo inflammation mapping of periodontal disease based on diffuse reflectance spectral imaging: a clinical study

    Science.gov (United States)

    Prasanth, Chandra Sekhar; Betsy, Joseph; Jayanthi, Jayaraj L.; Nisha, Unni G.; Prasantila, Janam; Subhash, Narayanan

    2013-02-01

    Since conventional techniques using periodontal probes have inherent drawbacks in the diagnosis of different grades of gingival inflammation, development of noninvasive screening devices becomes significant. Diffuse reflectance (DR) spectra recorded with white light illumination is utilized to detect periodontal inflammation from the oxygenated hemoglobin absorption ratio R620/R575. A multispectral imaging system is utilized to record narrow-band DR images at 575 and 620 nm from the anterior sextant of the gingivia of 15 healthy volunteers and 25 patients (N=40). An experienced periodontist assesses the level of gingival inflammation at each site through periodontal probing and assigns diagnosis as healthy, mild, moderate, or severe inflammation. The DR image ratio R620/R575 computed for each pixel (8-μm resolution) from the monochrome images is pseudo-color-mapped to identify gingival inflammation sites. The DR image ratio values at each site are compared with clinical diagnosis to estimate the specificity and sensitivity of the DR imaging technique in inflammation mapping. The high diagnostic accuracy is utilized to detect underlying inflammation in six patients with a previous history of periodontitis.

  7. Diffusion-weighted imaging of the pancreas; Diffusionsbildgebung des Pankreas

    Energy Technology Data Exchange (ETDEWEB)

    Gruenberg, K. [Deutsches Krebsforschungszentrum (DKFZ) Heidelberg, Abteilung Radiologie, E010, Heidelberg (Germany); Grenacher, L.; Klauss, M. [Universitaetsklinikum Heidelberg, Abt. Diagnostische und Interventionelle Radiologie, Heidelberg (Germany)

    2011-03-15

    Diffusion-weighted imaging (DWI) has increasingly gained in importance over the last 10 years especially in cancer imaging for differentiation of malignant and benign lesions. Through development of fast magnetic resonance imaging (MRI) sequences DWI is not only applicable in neuroradiology but also in abdominal imaging. As a diagnostic tool of the pancreas DWI enables a differentiation between normal tissue, cancer and chronic pancreatitis. The ADC values (apparent diffusion coefficient, the so-called effective diffusion coefficient) reported in the literature for healthy pancreatic tissue are in the range from 1.49 to 1.9 x 10{sup -3} mm{sup 2}/s, for pancreatic cancer in the range from 1.24 to 1.46 x 10{sup -3} mm{sup 2}/s and for autoimmune pancreatitis an average ADC value of 1.012 x 10{sup -3} mm{sup 2}/s. There are controversial data in the literature concerning the differentiation between chronic pancreatitis and pancreatic cancer. Using DWI-derived IVIM (intravoxel incoherent motion) the parameter f (perfusion fraction) seems to be advantageous but it is important to use several b values. In the literature the mean f value in chronic pancreatitis is around 16%, in pancreatic cancer 8% and in healthy pancreatic tissue around 25%. So far, DWI has not been helpful for differentiating cystic lesions of the pancreas. There are many references with other tumor entities and in animal models which indicate that there is a possible benefit of DWI in monitoring therapy of pancreatic cancer but so far no original work has been published. (orig.) [German] Die Diffusionsbildgebung (''diffusion-weighted imaging'', DWI) gewann in den letzten 10 Jahren insbesondere in der Tumorbildgebung zur Unterscheidung zwischen malignen und benignen Laesionen zunehmend an Bedeutung. Durch Entwicklung schnellerer MR-Sequenzen ist sie nicht nur in der Neuroradiologie, sondern auch in der Abdomenbildgebung einsetzbar. In der Pankreasdiagnostik ermoeglicht sie

  8. Magnetic resonance diffusion tensor imaging and fiber-tracking diffusion tensor tractography in the management of spinal astrocytomas.

    Science.gov (United States)

    Landi, Alessandro; Palmarini, Valeria; D'Elia, Alessandro; Marotta, Nicola; Salvati, Maurizio; Santoro, Antonio; Delfini, Roberto

    2016-01-16

    Some specially imaging of magnetic resonance imaging, the diffusion-weighted imaging (DWI), the diffusion tensor imaging and fractional anisotropy (FA), are useful to described, detect, and map the extent of spinal cord lesions. FA measurements may are used to predicting the outcome of patients who have spinal cord lesions. Fiber tracking enable to visualizing the integrity of white matter tracts surrounding some lesions, and this information could be used to formulating a differential diagnosis and planning biopsies or resection. In this article, we will describe the current uses for DWI and fiber tracking and speculate on others in which we believe these techniques will be useful in the future.

  9. Visual pathway impairment by pituitary adenomas: quantitative diagnostics by diffusion tensor imaging.

    Science.gov (United States)

    Lilja, Ylva; Gustafsson, Oscar; Ljungberg, Maria; Starck, Göran; Lindblom, Bertil; Skoglund, Thomas; Bergquist, Henrik; Jakobsson, Karl-Erik; Nilsson, Daniel

    2017-09-01

    OBJECTIVE Despite ample experience in surgical treatment of pituitary adenomas, little is known about objective indices that may reveal risk of visual impairment caused by tumor growth that leads to compression of the anterior visual pathways. This study aimed to explore diffusion tensor imaging (DTI) as a means for objective assessment of injury to the anterior visual pathways caused by pituitary adenomas. METHODS Twenty-three patients with pituitary adenomas, scheduled for transsphenoidal tumor resection, and 20 healthy control subjects were included in the study. A minimum suprasellar tumor extension of Grade 2-4, according to the SIPAP (suprasellar, infrasellar, parasellar, anterior, and posterior) scale, was required for inclusion. Neuroophthalmological examinations, conventional MRI, and DTI were completed in all subjects and were repeated 6 months after surgery. Quantitative assessment of chiasmal lift, visual field defect (VFD), and DTI parameters from the optic tracts was performed. Linear correlations, group comparisons, and prediction models were done in controls and patients. RESULTS Both the degree of VFD and chiasmal lift were significantly correlated with the radial diffusivity (r = 0.55, p visual pathways that were compressed by pituitary adenomas. The correlation between radial diffusivity and visual impairment may reflect a gradual demyelination in the visual pathways caused by an increased tumor effect. The low level of axial diffusivity found in the patient group may represent early atrophy in the visual pathways, detectable on DTI but not by conventional methods. DTI may provide objective data, detect early signs of injury, and be an additional diagnostic tool for determining indication for surgery in cases of pituitary adenomas.

  10. Added value of diffusion-weighted magnetic resonance imaging for the detection of pancreatic fluid collection infection

    Energy Technology Data Exchange (ETDEWEB)

    Borens, Bruno [Polyclinique Santa Maria, Nice (France); Arvanitakis, Marianna; Eisendrath, Pierre; Toussaint, Emmanuel; Deviere, Jacques [Erasme Hospital, Department of Gastroenterology, Brussels (Belgium); Absil, Julie; Matos, Celso; Bali, Maria Antonietta [Erasme Hospital, Department of Radiology, Brussels (Belgium); El Bouchaibi, Said [Epicura, Ath (Belgium)

    2017-03-15

    To investigate the added value of diffusion-weighted (DW) magnetic resonance (MR) imaging in the detection of infection in pancreatic fluid collections (PFC). Forty-patients with PFC requiring endoscopic-transmural drainage underwent conventional-MR and DW-MR imaging (b = 1000 s/mm{sup 2}) before endoscopy. MR images were divided into two sets (set1, conventional-MR; set2, conventional-MR, DW-MR and ADC maps) and randomized. Two independent readers performed qualitative and quantitative (apparent diffusion coefficient, ADC) image analysis. Bacteriological analysis of PFC content was the gold standard. Non-parametric tests were used for comparisons. Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) and accuracy were calculated for the two sets for both readers. Receiver operating characteristic curves (ROC) were drawn to assess quantitative DW-MR imaging diagnostic performance. For both readers, sensitivity, specificity, NPV, PPV and accuracy for infected PFCs were higher for set2 (P >.05). ADC were lower in infected versus non-infected PFCs (P ≤.031). Minimum ADC cut-off: 1,090 x 10{sup -3} mm{sup 2}/s for reader 1 and 1,012 x 10{sup -3} mm{sup 2}/s for reader 2 (sensitivity and specificity 67 % and 96 % for both readers). Qualitative information provided by DW-MR may help to assess PFCs infection. Infected PFCs show significantly lower ADCs compared to non-infected ones. (orig.)

  11. Noise removal in magnetic resonance diffusion tensor imaging.

    Science.gov (United States)

    Chen, Bin; Hsu, Edward W

    2005-08-01

    Although promising for visualizing the structure of ordered tissues, MR diffusion tensor imaging (DTI) has been hampered by long acquisition time and low spatial resolution associated with its inherently low signal-to-noise ratio (SNR). Moreover, the uncertainty in the DTI measurements has a direct impact on the accuracy of structural renderings such as fiber streamline tracking. Noise removal techniques can be used to improve the SNR of DTI without requiring additional acquisitions, albeit most low-pass filtering methods are accompanied by undesirable image blurring. In the present study, a modified vector-based partial-differential-equation (PDE) filtering formalism was implemented for smoothing DTI vector fields. Using an image residual-energy criterion to equate the degree of smoothing and error metrics empirically derived from DTI data to quantify the relative performances, the effectiveness in denoising DTI data is compared among image-based and vector-based PDE and fixed and adaptive low-pass k-space filtering. The results demonstrate that the edge-preservation feature of the PDE approach can be highly advantageous in enhancing DTI measurements, particularly for vector-based PDE filtering in applications relying on DTI directional information. These findings suggest a potential role for the postprocessing enhancement technique to improve the practical utility of DTI.

  12. Image Encryption Based on Diffusion and Multiple Chaotic Maps

    CERN Document Server

    Sathishkumar, G A; Sriraam, Dr N; 10.5121/ijnsa.2011.3214

    2011-01-01

    In the recent world, security is a prime important issue, and encryption is one of the best alternative way to ensure security. More over, there are many image encryption schemes have been proposed, each one of them has its own strength and weakness. This paper presents a new algorithm for the image encryption/decryption scheme. This paper is devoted to provide a secured image encryption technique using multiple chaotic based circular mapping. In this paper, first, a pair of sub keys is given by using chaotic logistic maps. Second, the image is encrypted using logistic map sub key and in its transformation leads to diffusion process. Third, sub keys are generated by four different chaotic maps. Based on the initial conditions, each map may produce various random numbers from various orbits of the maps. Among those random numbers, a particular number and from a particular orbit are selected as a key for the encryption algorithm. Based on the key, a binary sequence is generated to control the encryption algorit...

  13. Transient Ischemic Attack and Stroke Can Be Differentiated by Analyzing the Diffusion Tensor Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Tong [Fudan University Shanghai Cancer Center, Shanghai (China); Yao Zhenwei; Feng Xiaoyuan [Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai (China)

    2011-06-15

    We wanted to differentiate between transient ischemic attack (TIA) and minor stroke using fractional anisotropy and three-dimensional (3D) fiber tractography. The clinical data, conventional magnetic resonance imaging (MRI), diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) were obtained for 45 TIA patients and 33 minor stroke patients. The fractional anisotrophy ratio (rFA) between the lesion and the mirrored corresponding contralateral normal tissue was calculated and analyzed. The spatial relationship between the lesion and the corticospinal tract (CST) was analyzed and the lesion sizes in the minor stroke patients and TIA patients were compared. Twenty-two of the 45 TIA patients (49%) revealed focal abnormalities following DWI. The rFA was significantly lower (p < 0.05) in the stroke patients (0.71 {+-} 0.29) compared to that of the TIA patients (1.05 {+-} 0.37). The CST was involved in almost all stroke lesions, but it was not involved in 68% of the TIA lesions. The TIA patients had significantly lower CST injury scores (3.25 {+-} 1.75) than did the stroke patients (8.80 {+-} 2.39) (p = 0.004). Our data indicate that TIA and minor stroke can be identified by analyzing the rFA and the degree of CST involvement, and this may also allow more accurate prediction of a patient's long-term recovery or disability.

  14. Diffusion tensor magnetic resonance imaging of glial brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Ferda, Jiri, E-mail: ferda@fnplzen. [Department of Radiology, Charles University Hospital Plzen, Medical Faculty Plzen, Alej Svobody 80, 304 60 Plzen (Czech Republic); Kastner, Jan [Department of Radiology, Charles University Hospital Plzen, Medical Faculty Plzen, Alej Svobody 80, 304 60 Plzen (Czech Republic); Mukensnabl, Petr [Sikl' s Institute of Pathological Anatomy, Charles University Hospital Plzen, Medical Faculty Plzen, Alej Svobody 80, 304 60 Plzen (Czech Republic); Choc, Milan [Department of Neurosurgery, Charles University Hospital Plzen, Medical Faculty Plzen, Alej Svobody 80, 304 60 Plzen (Czech Republic); Horemuzova, Jana; Ferdova, Eva; Kreuzberg, Boris [Department of Radiology, Charles University Hospital Plzen, Medical Faculty Plzen, Alej Svobody 80, 304 60 Plzen (Czech Republic)

    2010-06-15

    Aim: To evaluate the author's experience with the use of diffusion tensor magnetic resonance imaging (DTI) on patients with glial tumors. Methods: A retrospective evaluation of a group of 24 patients with glial tumors was performed. There were eight patients with Grade II, eight patients with Grade III and eight patients with Grade IV tumors with a histologically proven diagnosis. All the patients underwent routine imaging including T2 weighted images, multidirectional diffusion weighted imaging (measured in 60 non-collinear directions) and T1 weighted non-enhanced and contrast enhanced images. The imaging sequence and evaluation software were produced by Massachusetts General Hospital Corporation (Boston, MA, USA). Fractional anisotropy (FA) maps were calculated in all patients. The white matter FA changes were assessed within the tumorous tissue, on the tumorous borderline and in the normally appearing white matter adjacent to the tumor. A three-dimensional model of the white matter tract was created to demonstrate the space relationship of the tumor and the capsula interna or corpus callosum in each case using the following fiber tracing parameters: FA step 0.25 and a tensor declination angle of 45 gr. An additional assessment of the tumorous tissue enhancement was performed. Results: A uniform homogenous structure with sharp demargination of the Grade II tumors and the wide rim of the intermedial FA in all Grade III tumors respectively, were found during the evaluation of the FA maps. In Grade IV tumors a variable demargination was noted on the FA maps. The sensitivity and specificity for the discrimination of low- and high-grade glial tumors using FA maps was revealed to be 81% and 87% respectively. If the evaluation of the contrast enhancement was combined with the evaluation of the FA maps, both sensitivity and specificity were 100%. Conclusion: Although the evaluation of the fractional anisotropy maps is not sufficient for glioma grading, the

  15. Functional multiparametric magnetic resonance imaging of the kidneys using blood oxygen level dependent and diffusion-weighted sequences.

    Science.gov (United States)

    Giannarini, Gianluca; Kessler, Thomas M; Roth, Beat; Vermathen, Peter; Thoeny, Harriet C

    2014-08-01

    Little data are available on noninvasive magnetic resonance imaging based assessment of renal function during upper urinary tract obstruction. We determined whether functional multiparametric kidney magnetic resonance imaging could monitor the treatment response in cases of acute unilateral upper urinary tract obstruction. Between January 2008 and January 2010, 18 patients with acute unilateral upper urinary tract obstruction due to calculi were prospectively enrolled to undergo kidney magnetic resonance imaging with conventional, blood oxygen level dependent and diffusion-weighted sequences upon emergency hospital admission and after release of obstruction. We assessed functional imaging parameters of obstructed and contralateral unobstructed kidneys derived from blood oxygen level dependent (apparent spin relaxation rate) and diffusion-weighted (total apparent diffusion coefficient, pure diffusion coefficient and perfusion fraction) sequences during acute upper urinary tract obstruction and after its release. During acute obstruction the apparent spin relaxation rate and perfusion fraction were lower in the cortex (p=0.020 and 0.031) and medulla (p=0.012 and 0.190, respectively) of obstructed kidneys compared to contralateral unobstructed kidneys. After obstruction release the apparent spin relaxation rate and perfusion fraction increased in the cortex (p=0.016 and 0.004) and medulla (p=0.071 and 0.044, respectively) of formerly obstructed kidneys to values similar to those in contralateral kidneys. Total apparent diffusion coefficient and pure diffusion coefficient values did not significantly differ between obstructed and contralateral unobstructed kidneys during or after obstruction. In our patients with acute unilateral upper urinary tract obstruction due to calculi functional kidney magnetic resonance imaging using blood oxygen level dependent and diffusion-weighted sequences enabled us to monitor pathophysiological changes in obstructed kidneys during

  16. Morphometry and diffusion MR imaging years after childhood traumatic brain injury.

    Science.gov (United States)

    Porto, Luciana; Jurcoane, Alina; Magerkurth, Joerg; Margerkurth, Joerg; Althaus, Jürgen; Zanella, Friedhelm; Hattingen, Elke; Kieslich, Matthias

    2011-11-01

    Our goal was to detect possible unrecognized injury in cerebral white matter (WM) in adult survivors of traumatic brain injury (TBI) during childhood, who showed no detectable axonal injury or chronic contusion on late conventional MRI. We used voxel-based morphometry (VBM) to detect subtle structural changes in brain morphology and diffusion-tensor imaging (DTI) to non-invasively probe WM integrity. By means of VBM and DTI we examined a group of 12 adult patients who suffered from childhood closed head injury without axonal injury on late conventional MRI. Patients sustained complicated mild or moderate-to-severe TBI with a mean of 7 points based on the Glasgow Coma Scale. The mean time after trauma was 19 years (range 7-31 years). For VBM, group comparisons of segmented T1-weighted grey matter and WM images were performed, while for DTI we compared the fractional anisotropy and mean diffusivity (MD) between the groups. Patients presented with higher MD in the right cerebral white matter, bilaterally in the forceps major and in the body and splenium of the corpus callosum. These findings were supported by VBM, which showed reduced WM volume bilaterally, mainly along the callosal splenium. Our results indicate that persistent focal long-term volume reduction and underlying WM structural changes may occur after TBI during childhood and that their effects extend into adulthood. Normal late conventional MR findings after childhood TBI do not rule out non-apparent axonal injury. Copyright © 2011 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  17. Simultaneous analysis and quality assurance for diffusion tensor imaging.

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    Carolyn B Lauzon

    Full Text Available Diffusion tensor imaging (DTI enables non-invasive, cyto-architectural mapping of in vivo tissue microarchitecture through voxel-wise mathematical modeling of multiple magnetic resonance imaging (MRI acquisitions, each differently sensitized to water diffusion. DTI computations are fundamentally estimation processes and are sensitive to noise and artifacts. Despite widespread adoption in the neuroimaging community, maintaining consistent DTI data quality remains challenging given the propensity for patient motion, artifacts associated with fast imaging techniques, and the possibility of hardware changes/failures. Furthermore, the quantity of data acquired per voxel, the non-linear estimation process, and numerous potential use cases complicate traditional visual data inspection approaches. Currently, quality inspection of DTI data has relied on visual inspection and individual processing in DTI analysis software programs (e.g. DTIPrep, DTI-studio. However, recent advances in applied statistical methods have yielded several different metrics to assess noise level, artifact propensity, quality of tensor fit, variance of estimated measures, and bias in estimated measures. To date, these metrics have been largely studied in isolation. Herein, we select complementary metrics for integration into an automatic DTI analysis and quality assurance pipeline. The pipeline completes in 24 hours, stores statistical outputs, and produces a graphical summary quality analysis (QA report. We assess the utility of this streamlined approach for empirical quality assessment on 608 DTI datasets from pediatric neuroimaging studies. The efficiency and accuracy of quality analysis using the proposed pipeline is compared with quality analysis based on visual inspection. The unified pipeline is found to save a statistically significant amount of time (over 70% while improving the consistency of QA between a DTI expert and a pool of research associates. Projection of QA

  18. Simultaneous analysis and quality assurance for diffusion tensor imaging.

    Science.gov (United States)

    Lauzon, Carolyn B; Asman, Andrew J; Esparza, Michael L; Burns, Scott S; Fan, Qiuyun; Gao, Yurui; Anderson, Adam W; Davis, Nicole; Cutting, Laurie E; Landman, Bennett A

    2013-01-01

    Diffusion tensor imaging (DTI) enables non-invasive, cyto-architectural mapping of in vivo tissue microarchitecture through voxel-wise mathematical modeling of multiple magnetic resonance imaging (MRI) acquisitions, each differently sensitized to water diffusion. DTI computations are fundamentally estimation processes and are sensitive to noise and artifacts. Despite widespread adoption in the neuroimaging community, maintaining consistent DTI data quality remains challenging given the propensity for patient motion, artifacts associated with fast imaging techniques, and the possibility of hardware changes/failures. Furthermore, the quantity of data acquired per voxel, the non-linear estimation process, and numerous potential use cases complicate traditional visual data inspection approaches. Currently, quality inspection of DTI data has relied on visual inspection and individual processing in DTI analysis software programs (e.g. DTIPrep, DTI-studio). However, recent advances in applied statistical methods have yielded several different metrics to assess noise level, artifact propensity, quality of tensor fit, variance of estimated measures, and bias in estimated measures. To date, these metrics have been largely studied in isolation. Herein, we select complementary metrics for integration into an automatic DTI analysis and quality assurance pipeline. The pipeline completes in 24 hours, stores statistical outputs, and produces a graphical summary quality analysis (QA) report. We assess the utility of this streamlined approach for empirical quality assessment on 608 DTI datasets from pediatric neuroimaging studies. The efficiency and accuracy of quality analysis using the proposed pipeline is compared with quality analysis based on visual inspection. The unified pipeline is found to save a statistically significant amount of time (over 70%) while improving the consistency of QA between a DTI expert and a pool of research associates. Projection of QA metrics to a low

  19. Correlations between diffusion-weighted imaging and breast cancer biomarkers

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    Martincich, Laura; Deantoni, Veronica; Bertotto, Ilaria; Liotti, Michele; Regge, Daniele [Unit of Radiology, Institute for Cancer Research and Treatment (IRCC), Candiolo, Turin (Italy); Redana, Stefania; Rossi, Valentina; Aglietta, Massimo; Montemurro, Filippo [Institute for Cancer Research and Treatment (IRCC), Division of Medical Oncology, Candiolo, Turin (Italy); Kubatzki, Franziska; Ponzone, Riccardo [Institute for Cancer Research and Treatment (IRCC), Division of Gynecological Oncology, Candiolo, Turin (Italy); Sarotto, Ivana [Unit of Pathology, Institute for Cancer Research and Treatment (IRCC), Candiolo, Turin (Italy)

    2012-07-15

    We evaluated whether the apparent diffusion coefficient (ADC) provided by diffusion-weighted imaging (DWI) varies according to biological features in breast cancer. DWI was performed in 190 patients undergoing dynamic contrast-enhanced magnetic resonance imaging (MRI) for local staging. For each of the 192 index cancers we studied the correlation between ADC and classical histopathological and immunohistochemical breast tumour features (size, histological type, grade, oestrogen receptor [ER] and Ki-67 expression, HER2 status). ADC was compared with immunohistochemical surrogates of the intrinsic subtypes (Luminal A; Luminal B; HER2-enriched; triple-negative). Correlations were analysed using the Mann-Whitney U and Kruskal-Wallis H tests. A weak, statistically significant correlation was observed between ADC values and the percentage of ER-positive cells (-0.168, P = 0.020). Median ADC values were significantly higher in ER-negative than in ER-positive tumours (1.110 vs 1.050 x 10{sup -3} mm{sup 2}/s, P = 0.015). HER2-enriched tumours had the highest median ADC value (1.190 x 10{sup -3} mm{sup 2}/s, range 0.950-2.090). Multiple comparisons showed that this value was significantly higher than that of Luminal A (1.025 x 10{sup -3} mm{sup 2}/s [0.700-1.340], P = 0.004) and Luminal B/HER2-negative (1.060 x 10{sup -3} mm{sup 2}/s [0.470-2.420], P = 0.008) tumours. A trend towards statistical significance (P = 0.018) was seen with Luminal B/HER2-positive tumours. ADC values vary significantly according to biological tumour features, suggesting that cancer heterogeneity influences imaging parameters. (orig.)

  20. Direct imaging of phase objects enables conventional deconvolution in bright field light microscopy.

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    Carmen Noemí Hernández Candia

    Full Text Available In transmitted optical microscopy, absorption structure and phase structure of the specimen determine the three-dimensional intensity distribution of the image. The elementary impulse responses of the bright field microscope therefore consist of separate absorptive and phase components, precluding general application of linear, conventional deconvolution processing methods to improve image contrast and resolution. However, conventional deconvolution can be applied in the case of pure phase (or pure absorptive objects if the corresponding phase (or absorptive impulse responses of the microscope are known. In this work, we present direct measurements of the phase point- and line-spread functions of a high-aperture microscope operating in transmitted bright field. Polystyrene nanoparticles and microtubules (biological polymer filaments serve as the pure phase point and line objects, respectively, that are imaged with high contrast and low noise using standard microscopy plus digital image processing. Our experimental results agree with a proposed model for the response functions, and confirm previous theoretical predictions. Finally, we use the measured phase point-spread function to apply conventional deconvolution on the bright field images of living, unstained bacteria, resulting in improved definition of cell boundaries and sub-cellular features. These developments demonstrate practical application of standard restoration methods to improve imaging of phase objects such as cells in transmitted light microscopy.

  1. Value of Apparent Diffusion Coefficient(ADC) of Diffusion eighted Magnetic Resonance Imaging in Common Renal Disease Diagnosis

    Institute of Scientific and Technical Information of China (English)

    Yuelang Zhang; Xingwang Sun; Guangnan Quan; Yongqian Qiang; Chenxia Li

    2008-01-01

    Objective:To find the value of the apparent diffusion coefficient (ADC) of diffusion weighted magnetic resonance imaging of common renal diseases. Methods: There were 30 healthy subjects and 81 patients with renal lesions (56 cases of renal carcinoma, 18 lesions of 12 cases of renal angiomyolipoma, and 21 lesions of 13 cases of renal cysts). Conventional magnetic resonance imaging and diffusion weighted magnetic resonance imaging were carded out. We measured the average ADC value of the renal lesions and normal kidneys. ADC maps from different b values were generated by a statistical package. Results: The ADC values of normal kidneys with three different motion-probing gradients(b=500, 800, 1000 sec/mm2) were 2.78±0.14×10-3mm2s-1,2.45±0.13×10-3mm2s-1, 2.13±0.14×10-3mm2s-1, respectively. The ADC values of renal cell carcinoma with three different motion-probing gradients(b=500, 800, 1008 sec/mm2) were 1.63±0.14×10-3mm2s-1, 1.31±0.18×10-3mm2s-1, 1.07±0.15-310-3mm2s-1, respectively. Among the renal cell carcinoma, the ADC value of clear cell type were 1.67±0.09×10-3mm2s-1, 1.36±0.13×10-3mm2s-1, 1.15±0.14×10-3mm2s-1,respectively; the ADC values of granular cell type were 1.59±0.19×10-3mm2s-1, 1.25±0.22×10-3mm2s-1, 0.97±0.12×10-3mm2s-1, respectively. The ADC values of renal angiomyolipoma with three different motion-probing gradients(b=500, 800, 1008 sec/mm2) were 0.88±0.08×10-3mm2s-1, 0.63±0.07×10-3mm2s-1, 0.43±0.04×10-3mm2s-1, respectively. The ADC values of renal cystic lesions with three different motion-probing gradients(b=500, 800, 1000 sec/mm2) were 3.73±0.18×10-3mm2s-1, 3.44±0.13×10-3mm2s-1, 3.09±0.21×10-3mm2s-1, respectively. Statistically significant differences exists between the ADC values of normal kidney, renal carcinomas, renal angiomyolipomas and renal cysts when the b value is the same. Among the different cell types of renal carcinomas, the ADC value of granular cell carcinoma is lower than that of clear cell

  2. Current Clinical Applications and Future Potential of Diffusion Tensor Imaging in Traumatic Brain Injury.

    Science.gov (United States)

    Strauss, Sara; Hulkower, Miriam; Gulko, Edwin; Zampolin, Richard L; Gutman, David; Chitkara, Munish; Zughaft, Malka; Lipton, Michael L

    2015-12-01

    In the setting of acute central nervous system (CNS) emergencies, computed tomography (CT) and conventional magnetic resonance imaging (MRI) play an important role in the identification of life-threatening intracranial injury. However, the full extent or even presence of brain damage frequently escapes detection by conventional CT and MRI. Advanced MRI techniques such as diffusion tensor imaging (DTI) are emerging as important adjuncts in the diagnosis of microstructural white matter injury in the acute and postacute brain-injured patient. Although DTI aids in detection of brain injury pathology, which has been repeatedly associated with typical adverse clinical outcomes, the evolution of acute changes and their long-term prognostic implications are less clear and the subject of much active research. A major aim of current research is to identify imaging-based biomarkers that can identify the subset of TBI patients who are at risk for adverse outcome and can therefore most benefit from ongoing care and rehabilitation as well as future therapeutic interventions.The aim of this study is to introduce the current methods used to obtain DTI in the clinical setting, describe a set of common interpretation strategies with their associated advantages and pitfalls, as well as illustrate the clinical utility of DTI through a set of specific patient scenarios. We conclude with a discussion of future potential for the management of TBI.

  3. Better visualization of vermiform appendix with tissue harmonic imaging compared to conventional sonography.

    Science.gov (United States)

    Inal, Mikail; Unal, Birsen; Bilgili, Yasemin Karadeniz

    2014-12-01

    Surgery of appendicitis carries 7-11% negative appendectomy rates. Sonographically visualized normal appendix precludes unnecessary computed tomography (CT) examination and may reduce negative appendectomy rates. Tissue harmonic imaging (THI) has been reported to improve the overall image quality. We aimed to assess whether THI is more successful than conventional ultrasonography (US) in detecting normal and pathologic appendices. The study was performed on 185 patients who applied for routine US examinations in whom clinical findings of appendicitis were detected in 25. We searched for the appendix; applying both THI and conventional US to each patient, one before and the other after the routine US examinations. Patients were divided into two groups; one was evaluated first with conventional US and the other first with THI. When the appendix was found, localization, diameter and time spent for visualization were recorded. Twelve patients were operated; all of whom had appendicitis pathologically. Two methods were compared for: 1. Success rates in all patients; female, male and child groups separately; 2. Visualization of pathologic and normal appendices; 3. Time for visualization of appendix; 4. Comparison of success rates in the adult and child population. The relationship between the rate of visualization and body mass index was evaluated. The appendix was visualized better by THI in all patients, and in the female and male groups (P imaging). THI visualizes appendix better than conventional US. It is a simple and time saving method that may eliminate further diagnostic imaging, and it may decrease negative appendectomy rates and related complications.

  4. DIAGNOSTIC VALUE OF WHOLE BODY DIFFUSION WEIGHTED IMAGING FOR SCREENING PRIMARY TUMORS OF PATIENTS WITH METASTASES

    Institute of Scientific and Technical Information of China (English)

    Tai-fu Gu; Xin-lan Xiao; Fei Sun; Jian-hua Yin; Hai Zhao

    2008-01-01

    Objective To evaluate the values of whole body diffusion weighted imaging (DWI) in screening primary unknown tumor in patients with metastases.Methods Totally, 34 patients with metastases of primary unknown tumors were scanned with whole body DWI, and conventional magnetic resonance (MR) imaging was performed if suspected lesions were detected. All the metastases including 27 cases of osseous metastases, 2 brain metastases, 2 liver metastases, 1 pulmonary multiple metastasis, 1 neck metastasis and 1 malignant ascites, were diagnosed by computed tomography, single photon emission computed tomography, or MR imaging. For the proven primary tumors diagnosed by biopsy or pathology of surgical specimens, apparent diffusion coefficient (ADC) values of the primary and metastatic lesions were measured respectively. The sensitivity and specificity of this technique for screening primary tumors were evaluated. Results We found 24 cases with suspected primary lesions, in which 23 lesions were proved to be primary tumors, and 1 was proved to be benign lesion. And no definite primary lesion was found in 10 cases on whole body DWI, but in which 1 case was diagnosed with primary tumor by biopsy later, and the other 9 cases remained unknown within follow-up of over half a year. The difference was not significant in ADC values between primary and metastatic lesions (P>0.05). The sensitivity and specificity of whole body DWI for searching primary tumors was 95.8% and 90.0%, respectively. Conclusion Combined with conventional MR scanning, whole body DWI can help to search primary lesions of patients with metastases.

  5. Overlay of conventional angiographic and en-face OCT images enhances their interpretation

    Directory of Open Access Journals (Sweden)

    Pool Chris W

    2005-06-01

    Full Text Available Abstract Background Combining characteristic morphological and functional information in one image increases pathophysiologic understanding as well as diagnostic accuracy in most clinical settings. En-face optical coherence tomography (OCT provides a high resolution, transversal OCT image of the macular area combined with a confocal image of the same area (OCT C-scans. Creating an overlay image of a conventional angiographic image onto an OCT image, using the confocal part to facilitate transformation, combines structural and functional information of the retinal area of interest. This paper describes the construction of such overlay images and their aid in improving the interpretation of OCT C-scans. Methods In various patients, en-face OCT C-scans (made with a prototype OCT-Ophthalmoscope (OTI, Canada in use at the Department of Ophthalmology (Academic Medical Centre, Amsterdam, The Netherlands and conventional fluorescein angiography (FA were performed. ImagePro, with a custom made plug-in, was used to make an overlay-image. The confocal part of the OCT C-scan was used to spatially transform the FA image onto the OCT C-scan, using the vascular arcades as a reference. To facilitate visualization the transformed angiographic image and the OCT C-scan were combined in an RGB image. Results The confocal part of the OCT C-scan could easily be fused with angiographic images. Overlay showed a direct correspondence between retinal thickening and FA leakage in Birdshot retinochoroiditis, localized the subretinal neovascular membrane and correlated anatomic and vascular leakage features in myopia, and showed the extent of retinal and pigment epithelial detachment in retinal angiomatous proliferation as FA leakage was subject to blocked fluorescence. The overlay mode provided additional insight not readily available in either mode alone. Conclusion Combining conventional angiographic images and en-face OCT C-scans assists in the interpretation of both

  6. Source effects in analyzer-based X-ray phase contrast imaging with conventional sources

    Energy Technology Data Exchange (ETDEWEB)

    Hoennicke, M. G. [Universidade Federal da Integracao Latino-Americana, 85867-970 Foz do Iguacu, PR (Brazil); Manica, J. [Universidade Estadual do Oeste do Parana, 85867-970 Foz do Iguacu, PR (Brazil); Mazzaro, I.; Cusatis, C. [LORXI, Departamento de Fisica, Universidade Federal do Parana, Caixa Postal 19091, 81531-990 Curitiba, PR (Brazil); Huang, X.-R. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2012-11-15

    Several recent papers have shown the implementation of analyzer based X-ray phase contrast imaging (ABI) with conventional X-ray sources. The high flux is always a requirement to make the technique useful for bio-medical applications. Here, we present and discuss three important parameters, which need to be taken into account, when searching for the high flux ABI: anisotropic magnification, double image, and source size spread due to intrinsic dispersive diffraction by asymmetrically cut crystals. These parameters, if not well optimized, may cause important features in the acquired images which can mislead the interpretation. A few ways to minimize these effects are implemented and discussed, including some experimental results.

  7. Longitudinal cerebellar diffusion tensor imaging changes in posterior fossa syndrome

    Directory of Open Access Journals (Sweden)

    Sean D. McEvoy, MD

    2016-01-01

    Full Text Available Posterior fossa syndrome is a severe transient loss of language that frequently complicates resection of tumors of the cerebellum. The associated pathophysiology and relevant anatomy to this language deficit remains controversial. We performed a retrospective analysis of all cerebellar tumor resections at Seattle Children's Hospital from 2010 to 2015. Diffusion tensor imaging was performed on each of the patients as part of their clinical scan. Patients included in the study were divided into groups based on language functioning following resection: intact (N = 19, mild deficit (N = 19, and posterior fossa syndrome (N = 9. Patients with posterior fossa syndrome showed white matter changes evidenced by reductions in fractional anisotropy in the left and right superior cerebellar peduncle following resection, and these changes were still evident 1-year after surgery. These changes were greater in the superior cerebellar peduncle than elsewhere in the cerebellum. Prior to surgery, posterior fossa patients did not show changes in fractional anisotropy however differences were observed in mean and radial diffusivity measures in comparison to other groups which may provide a radiographic marker of those at greatest risk of developing post-operative language loss.

  8. Diffusion-weighted MR imaging of the normal fetal lung

    Energy Technology Data Exchange (ETDEWEB)

    Balassy, Csilla; Kasprian, Gregor; Weber, Michael; Hoermann, Marcus; Bankier, Alexander; Herold, Christian J.; Prayer, Daniela [Medical University of Vienna, Department of Radiology, Vienna (Austria); Brugger, Peter C. [Medical University of Vienna, Center of Anatomy and Cell Biology, Vienna (Austria); Csapo, Bence [Medical University of Vienna, Department of Obstetrics and Gyneocology, Vienna (Austria); Bammer, Roland [University of Stanford, Department of Radiology, Stanford, CA (United States)

    2008-04-15

    To quantify apparent diffusion coefficient (ADC) changes in fetuses with normal lungs and to determine whether ADC can be used in the assessment of fetal lung development. In 53 pregnancies (20-37th weeks of gestation), we measured ADC on diffusion-weighted imaging (DWI) in the apical, middle, and basal thirds of the right lung. ADCs were correlated with gestational age. Differences between the ADCs were assessed. Fetal lung volumes were measured on T2-weighted sequences and correlated with ADCs and with age. ADCs were 2.13 {+-} 0.44 {mu}m{sup 2}/ms (mean {+-} SD) in the apex, 1.99 {+-} 0.42 {mu}m{sup 2}/ms (mean {+-} SD) in the middle third, and 1.91 {+-} 0.41 {mu}m{sup 2}/ms (mean {+-} SD) in the lung base. Neither the individual ADC values nor average ADC values showed a significant correlation with gestational age or with lung volumes. Average ADCs decreased significantly from the lung apex toward the base. Individual ADCs showed little absolute change and heterogeneity. Lung volumes increased significantly during gestation. We have not been able to identify a pattern of changes in the ADC values that correlate with lung maturation. Furthermore, the individual, gravity-related ADC changes are subject to substantial variability and show nonuniform behavior. ADC can therefore not be used as an indicator of lung maturity. (orig.)

  9. Adaptive distance metric learning for diffusion tensor image segmentation.

    Science.gov (United States)

    Kong, Youyong; Wang, Defeng; Shi, Lin; Hui, Steve C N; Chu, Winnie C W

    2014-01-01

    High quality segmentation of diffusion tensor images (DTI) is of key interest in biomedical research and clinical application. In previous studies, most efforts have been made to construct predefined metrics for different DTI segmentation tasks. These methods require adequate prior knowledge and tuning parameters. To overcome these disadvantages, we proposed to automatically learn an adaptive distance metric by a graph based semi-supervised learning model for DTI segmentation. An original discriminative distance vector was first formulated by combining both geometry and orientation distances derived from diffusion tensors. The kernel metric over the original distance and labels of all voxels were then simultaneously optimized in a graph based semi-supervised learning approach. Finally, the optimization task was efficiently solved with an iterative gradient descent method to achieve the optimal solution. With our approach, an adaptive distance metric could be available for each specific segmentation task. Experiments on synthetic and real brain DTI datasets were performed to demonstrate the effectiveness and robustness of the proposed distance metric learning approach. The performance of our approach was compared with three classical metrics in the graph based semi-supervised learning framework.

  10. Adaptive distance metric learning for diffusion tensor image segmentation.

    Directory of Open Access Journals (Sweden)

    Youyong Kong

    Full Text Available High quality segmentation of diffusion tensor images (DTI is of key interest in biomedical research and clinical application. In previous studies, most efforts have been made to construct predefined metrics for different DTI segmentation tasks. These methods require adequate prior knowledge and tuning parameters. To overcome these disadvantages, we proposed to automatically learn an adaptive distance metric by a graph based semi-supervised learning model for DTI segmentation. An original discriminative distance vector was first formulated by combining both geometry and orientation distances derived from diffusion tensors. The kernel metric over the original distance and labels of all voxels were then simultaneously optimized in a graph based semi-supervised learning approach. Finally, the optimization task was efficiently solved with an iterative gradient descent method to achieve the optimal solution. With our approach, an adaptive distance metric could be available for each specific segmentation task. Experiments on synthetic and real brain DTI datasets were performed to demonstrate the effectiveness and robustness of the proposed distance metric learning approach. The performance of our approach was compared with three classical metrics in the graph based semi-supervised learning framework.

  11. Diffusion-weighted MR imaging of the normal fetal lung.

    Science.gov (United States)

    Balassy, Csilla; Kasprian, Gregor; Brugger, Peter C; Csapo, Bence; Weber, Michael; Hörmann, Marcus; Bankier, Alexander; Bammer, Roland; Herold, Christian J; Prayer, Daniela

    2008-04-01

    To quantify apparent diffusion coefficient (ADC) changes in fetuses with normal lungs and to determine whether ADC can be used in the assessment of fetal lung development. In 53 pregnancies (20-37th weeks of gestation), we measured ADC on diffusion-weighted imaging (DWI) in the apical, middle, and basal thirds of the right lung. ADCs were correlated with gestational age. Differences between the ADCs were assessed. Fetal lung volumes were measured on T2-weighted sequences and correlated with ADCs and with age. ADCs were 2.13 +/- 0.44 microm(2)/ms (mean +/- SD) in the apex, 1.99 +/- 0.42 microm(2)/ms (mean +/- SD) in the middle third, and 1.91 +/- 0.41 microm(2)/ms (mean +/- SD) in the lung base. Neither the individual ADC values nor average ADC values showed a significant correlation with gestational age or with lung volumes. Average ADCs decreased significantly from the lung apex toward the base. Individual ADCs showed little absolute change and heterogeneity. Lung volumes increased significantly during gestation. We have not been able to identify a pattern of changes in the ADC values that correlate with lung maturation. Furthermore, the individual, gravity-related ADC changes are subject to substantial variability and show nonuniform behavior. ADC can therefore not be used as an indicator of lung maturity.

  12. Longitudinal diffusion tensor imaging in amyotrophic lateral sclerosis

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    Keil Carsten

    2012-11-01

    Full Text Available Abstract Background Amyotrophic lateral sclerosis (ALS is a fatal neurodegenerative disorder, caused by progressive loss of motor neurons. Changes are widespread in the subcortical white matter in ALS. Diffusion tensor imaging (DTI detects pathological changes in white matter fibres in vivo, based on alterations in the degree (diffusivity, ADC and directedness (fractional anisotropy, FA of proton movement. Methods 24 patients with ALS and 24 age-matched controls received 1.5T DTI. FA and ADC were analyzed using statistical parametric mapping. In 15 of the 24 ALS patients, a second DTI was obtained after 6 months. Results Decreased FA in the corticospinal tract (CST and frontal areas confirm existing results. With a direct comparison of baseline and follow-up dataset, the progression of upper motor neuron degeneration, reflected in FA decrease, could be captured along the CST and in frontal areas. The involvement of cerebellum in the pathology of ALS, as suspected from functional MRI studies, could be confirmed by a reduced FA (culmen, declive. These structural changes correlated well with disease duration, ALSFRS-R, and physical and executive functions. Conclusion DTI detects changes that are regarded as prominent features of ALS and thus, shows promise in its function as a biomarker. Using the technique herein, we could demonstrate DTI changes at follow-up which correlated well with clinical progression.

  13. Proton MR Spectroscopy and Diffusion MR Imaging Monitoring to Predict Tumor Response to Interstitial Photodynamic Therapy for Glioblastoma

    Science.gov (United States)

    Toussaint, Magali; Pinel, Sophie; Auger, Florent; Durieux, Nicolas; Thomassin, Magalie; Thomas, Eloise; Moussaron, Albert; Meng, Dominique; Plénat, François; Amouroux, Marine; Bastogne, Thierry; Frochot, Céline; Tillement, Olivier; Lux, François; Barberi-Heyob, Muriel

    2017-01-01

    Despite recent progress in conventional therapeutic approaches, the vast majority of glioblastoma recur locally, indicating that a more aggressive local therapy is required. Interstitial photodynamic therapy (iPDT) appears as a very promising and complementary approach to conventional therapies. However, an optimal fractionation scheme for iPDT remains the indispensable requirement. To achieve that major goal, we suggested following iPDT tumor response by a non-invasive imaging monitoring. Nude rats bearing intracranial glioblastoma U87MG xenografts were treated by iPDT, just after intravenous injection of AGuIX® nanoparticles, encapsulating PDT and imaging agents. Magnetic Resonance Imaging (MRI) and Magnetic Resonance Spectroscopy (MRS) allowed us an original longitudinal follow-up of post-treatment effects to discriminate early predictive markers. We successfully used conventional MRI, T2 star (T2*), Diffusion Weighted Imaging (DWI) and MRS to extract relevant profiles on tissue cytoarchitectural alterations, local vascular disruption and metabolic information on brain tumor biology, achieving earlier assessment of tumor response. From one day post-iPDT, DWI and MRS allowed us to identify promising markers such as the Apparent Diffusion Coefficient (ADC) values, lipids, choline and myoInositol levels that led us to distinguish iPDT responders from non-responders. All these responses give us warning signs well before the tumor escapes and that the growth would be appreciated. PMID:28255341

  14. A hitchhiker’s guide to Diffusion Tensor Imaging

    Directory of Open Access Journals (Sweden)

    Jose eSoares

    2013-03-01

    Full Text Available Diffusion Tensor Imaging (DTI studies are increasingly popular among clinicians and researchers as they provide unique insights into brain network connectivity. However, in order to optimize the use of DTI, several technical and methodological aspects must be factored in. These include decisions on: acquisition protocol, artifact handling, data quality control, reconstruction algorithm and visualization approaches, and quantitative analysis methodology. Furthermore, the researcher and/or clinician also needs to take into account and decide on the most suited software tool(s for each stage of the DTI analysis pipeline. Herein, we provide a straightforward hitchhiker’s guide, covering all of the workflow’s major stages. Ultimately, this guide will help newcomers navigate the most critical roadblocks in the analysis and further encourage the use of DTI.

  15. Diffusion magnetic resonance imaging in transient global amnesia

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    Godeiro-Junior, Clecio; Miranda-Alves, Maramelia Araujo de [Federal University of Sao Paulo (UNIFESP-EPM), Sao Paulo SP (Brazil). Dept. of Neurology and Neurosurgery], e-mail: cleciojunior@yahoo.com.br; Massaro, Ayrton Roberto [Fleury Diagnostic Center, Sao Paulo SP (Brazil)

    2009-03-15

    Transient global amnesia (TGA) is a well known clinical entity characterized by anterograde memory disturbance of sudden onset that lasts 1 to 24 hours. Orientation in space and time is impaired while consciousness remains undisturbed. TGA may refer to a single expression of several physiopathological phenomena. Conceptually, cerebral ischemia, epileptic discharge, and migraine constitute the main pathogenic hypothesis. Diffusion-weighted imaging (DWI) has become a powerful tool in the evaluation of patients with suspected stroke owing to its high sensitivity and specificity, even for small areas of acute ischemia. Consequently, this method has also been applied to TGA to gain further insights into the ischemic hypothesis of this condition. We report a patient with a typical TGA presentation and MRI findings suggestive of an ischemic insult. We further discuss the ischemic hypothesis of TGA. (author)

  16. Magnetic resonance diffusion tensor imaging (MRDTI) and tractography in children with septo-optic dysplasia

    Energy Technology Data Exchange (ETDEWEB)

    Salmela, Michael B. [University of Vermont College of Medicine-Fletcher Allen Health Care, Burlington, VT (United States); Cauley, Keith A. [UMass Memorial Medical Center, Department of Radiology, Worcester, MA (United States); Nickerson, Joshua P.; Filippi, Christopher G. [University of Vermont College of Medicine-Fletcher Allen Health Care, Department of Radiology, Burlington, VT (United States); Koski, Chris J. [James Madison University, Department of Political Science, Harrisonburg, VA (United States)

    2010-05-15

    Septo-optic dysplasia (SOD) refers to a heterogeneous group of midline brain developmental anomalies, with optic nerve hypoplasia (ONH) being one of the morphologic correlates of the condition. Traditionally, ONH has been diagnosed on fundoscopic exam. Conventional MRI is used in cases of suspected ONH to identify associated brain abnormalities and to compare findings to the fundoscopic exam. Advances in magnetic resonance diffusion tensor imaging (MRDTI) permit in vivo, noninvasive, quantitative characterization of the entire visual pathway at 3.0 T. To investigate the feasibility of MRDTI at 3.0 T in children with SOD to evaluate the entire visual pathway. MRDTI at 3T was performed in two children with SOD and seven age-matched controls. Manual region-of-interest analysis was used to evaluate the tensor metrics of the optic nerves. Deterministic tractography was used to evaluate the tensor metrics of the optic radiations. The SOD patients demonstrated a significant decrease in anisotropy and increase in mean diffusivity of the optic nerves and radiations compared to the control subjects. This study demonstrates the feasibility of MRDTI to evaluate the entire visual pathway in children, and it demonstrates pre- and post-chiasmatic diffusion tensor abnormalities in SOD patients. (orig.)

  17. Computed and conventional chest radiography: a comparison of image quality and radiation dose.

    Science.gov (United States)

    Ramli, K; Abdullah, B J J; Ng, K-H; Mahmud, R; Hussain, A F

    2005-12-01

    The aim of this study was to compare the image quality and entrance skin dose (ESD) for film-screen and computed chest radiography. Analysis of the image quality and dose on chest radiography was carried out on a conventional X-ray unit using film-screen, storage phosphor plates and selenium drum direct chest radiography. For each receptor, ESD was measured in 60 patients using thermoluminescent dosemeters. Images were printed on 35 x 43 cm films. Image quality was assessed subjectively by evaluation of anatomic features and estimation of the image quality, following the guidelines established by the protocols of the Commission of the European Communities. There was no statistically significant difference noted between the computed and conventional images (Wilcoxon rank sum test, P > 0.05). Imaging of the mediastinum and peripheral lung structures were better visualized with the storage phosphor and selenium drum technique than with the film-screen combination. The patients' mean ESD for chest radiography using the storage phosphor, film-screen combination and selenium drum was 0.20, 0.20 and 0.25 mGy, respectively, with no statistically significant difference with P > 0.05 (chi(2) tests).

  18. Application of neurite orientation dispersion and density imaging or diffusion tensor imaging to quantify the severity of cervical spondylotic myelopathy and to assess postoperative neurologic recovery.

    Science.gov (United States)

    Okita, Genki; Ohba, Tetsuro; Takamura, Tomohiro; Ebata, Shigeto; Ueda, Ryo; Onishi, Hiroshi; Haro, Hirotaka; Hori, Masaaki

    2017-07-12

    Surgical outcome and the severity of cervical spondylotic myelopathy (CSM) are unpredictable and cannot be estimated by conventional anatomical magnetic resonance imaging (MRI). The utility of diffusion tensor imaging (DTI) to quantify the severity of CSM and to assess postoperative neurologic recovery has been investigated. However, whether conventional DTI should be applied in a clinical setting remains controversial. Neurite orientation dispersion and density imaging (NODDI) is a recently introduced model-based diffusion-weighted MRI technique that quantifies specific microstructural features related directly to neuronal morphology. However, there are as yet few clinical applications of NODDI reported. Indeed, there are no reports to indicate NODDI is useful for diagnosing CSM. This is a retrospective cohort study using consecutive patients. The objective of this study was to evaluate the utility of NODDI and conventional DTI for detecting changes in the spinal cord microstructure. In particular, this study aimed to quantify the preoperative severity of CSM and to assess postoperative neurologic recovery from this myelopathy. We included 27 consecutive patients with a nontraumatic cervical lesion from CSM who underwent laminoplasty at a single institution between April 2012 and April 2015. The patients underwent MRI before and approximately 2 weeks after surgery. In addition to conventional DTI metrics, we evaluated the intracellular volume fraction (ICVF) and the orientation dispersion index (ODI), which are metrics derived from NODDI. The 10-second grip and release test and the Japanese Orthopaedic Association scoring system were used before and 1 year after surgery to assess neurologic outcome. Neurite orientation dispersion and density imaging and conventional DTI values were measured at the C2-C3 intervertebral level (control value) and at the most compressed levels (C3-C7 intervertebral levels) were measured. The changes in these values pre- and

  19. An investigation of diffusion imaging techniques in the evaluation of spinocerebellar ataxia and multisystem atrophy.

    Science.gov (United States)

    Rozenfeld, Michael N; Nemeth, Alexander J; Walker, Matthew T; Mohan, Prasoon; Wang, Xue; Parrish, Todd B; Opal, Puneet

    2015-01-01

    Multisystem system atrophy and spinocerebellar ataxia are rare neurodegenerative ataxias that can be difficult to diagnose, with important prognostic and treatment implications. The purpose of this study is to evaluate various methods of diffusion imaging and tractography in their effectiveness at differentiating these diseases from control subjects. Our secondary aim is determining whether diffusion abnormalities correspond with clinical disease severity. Diffusion imaging and tractography were performed on five patients and seven age-matched controls. Fractional anisotropy, generalized fractional anisotropy, and apparent diffusion coefficient values and corticospinal tract volumes were measured within various diffusion and probabilistic tractography models, including standard diffusion tensor and Q-ball tractography. Standard diffusion based fractional anisotropy and apparent diffusion coefficient values were significantly altered in patients versus controls in the middle cerebellar peduncles and central pons. Tractography based fractional anisotropy and generalized fractional anisotropy values were significantly lower in patients versus controls when corticospinal tracts were drawn in a craniocaudal direction (bilaterally using Q-ball imaging, only on the right using diffusion tensor imaging). The right corticospinal tract volume was significantly smaller in patients versus controls when created using Q-ball imaging in a caudocranial direction. There was no correlation between diffusion alteration and clinical symptomatology. In conclusion, various diffusion-based techniques can be effective in differentiating ataxic patients from control subjects, although the selection of diffusion algorithm and tract growth technique and direction is non-trivial.

  20. Spatial mapping of structural and connectional imaging data for the developing human brain with diffusion tensor imaging.

    Science.gov (United States)

    Ouyang, Austin; Jeon, Tina; Sunkin, Susan M; Pletikos, Mihovil; Sedmak, Goran; Sestan, Nenad; Lein, Ed S; Huang, Hao

    2015-02-01

    During human brain development from fetal stage to adulthood, the white matter (WM) tracts undergo dramatic changes. Diffusion tensor imaging (DTI), a widely used magnetic resonance imaging (MRI) modality, offers insight into the dynamic changes of WM fibers as these fibers can be noninvasively traced and three-dimensionally (3D) reconstructed with DTI tractography. The DTI and conventional T1 weighted MRI images also provide sufficient cortical anatomical details for mapping the cortical regions of interests (ROIs). In this paper, we described basic concepts and methods of DTI techniques that can be used to trace major WM tracts noninvasively from fetal brain of 14 postconceptional weeks (pcw) to adult brain. We applied these techniques to acquire DTI data and trace, reconstruct and visualize major WM tracts during development. After categorizing major WM fiber bundles into five unique functional tract groups, namely limbic, brain stem, projection, commissural and association tracts, we revealed formation and maturation of these 3D reconstructed WM tracts of the developing human brain. The structural and connectional imaging data offered by DTI provides the anatomical backbone of transcriptional atlas of the developing human brain. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Motion Correction of Multi-b-value Diffusion-weighted Imaging in the Liver

    Science.gov (United States)

    Mazaheri, Yousef; Do, Richard K. G.; Shukla-Dave, Amita; Deasy, Joseph O.; Lu, Yonggang; Akin, Oguz

    2016-01-01

    Rationale and Objectives Motion artifacts are a significant source of error in the acquisition and quantification of parameters from multi-b-value diffusion-weighted imaging (DWI). The objective of this article is to present a reliable method to reduce motion-related artifacts during free-breathing at higher b-values when signal levels are low. Materials and Methods Twelve patients referred for magnetic resonance imaging of the liver underwent a clinical magnetic resonance imaging examination of the abdominal region that included DWI. Conventional single-shot spin-echo echo planar imaging acquisitions of the liver during free breathing were repeated in a “time-resolved” manner during a single acquisition to obtain data for multi-b-value analysis, alternating between low and high b-values. Image registration using a normalized mutual information similarity measure was used to correct for spatial misalignment of diffusion-weighted volumes caused by motion. Registration error was estimated indirectly by comparing the normalized root-mean-square error (NRMSE) values of data fitted to the biexponential intra-voxel incoherent motion model before and after motion correction. Regions of interest (ROIs) were selected in the liver close to the surface of the liver and close to internal structures such as large bile ducts and blood vessels. Results For the 12 patient datasets, the mean NRMSE value for the motion-corrected ROIs (0.38 ± 0.16) was significantly lower than the mean NRMSE values for the non–motion-corrected ROIs (0.41 ± 0.13) (P < .05). In cases where there was substantial respiratory motion during the acquisition, visual inspection verified that the algorithm markedly improved alignment of the liver contours between frames. Conclusions The proposed method addresses motion-related artifacts to increase robustness in multi-b-value acquisitions. PMID:22963726

  2. 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].

  3. Neurite density imaging versus imaging of microscopic anisotropy in diffusion MRI: A model comparison using spherical tensor encoding.

    Science.gov (United States)

    Lampinen, Björn; Szczepankiewicz, Filip; Mårtensson, Johan; van Westen, Danielle; Sundgren, Pia C; Nilsson, Markus

    2017-02-15

    In diffusion MRI (dMRI), microscopic diffusion anisotropy can be obscured by orientation dispersion. Separation of these properties is of high importance, since it could allow dMRI to non-invasively probe elongated structures such as neurites (axons and dendrites). However, conventional dMRI, based on single diffusion encoding (SDE), entangles microscopic anisotropy and orientation dispersion with intra-voxel variance in isotropic diffusivity. SDE-based methods for estimating microscopic anisotropy, such as the neurite orientation dispersion and density imaging (NODDI) method, must thus rely on model assumptions to disentangle these features. An alternative approach is to directly quantify microscopic anisotropy by the use of variable shape of the b-tensor. Along those lines, we here present the 'constrained diffusional variance decomposition' (CODIVIDE) method, which jointly analyzes data acquired with diffusion encoding applied in a single direction at a time (linear tensor encoding, LTE) and in all directions (spherical tensor encoding, STE). We then contrast the two approaches by comparing neurite density estimated using NODDI with microscopic anisotropy estimated using CODIVIDE. Data were acquired in healthy volunteers and in glioma patients. NODDI and CODIVIDE differed the most in gray matter and in gliomas, where NODDI detected a neurite fraction higher than expected from the level of microscopic diffusion anisotropy found with CODIVIDE. The discrepancies could be explained by the NODDI tortuosity assumption, which enforces a connection between the neurite density and the mean diffusivity of tissue. Our results suggest that this assumption is invalid, which leads to a NODDI neurite density that is inconsistent between LTE and STE data. Using simulations, we demonstrate that the NODDI assumptions result in parameter bias that precludes the use of NODDI to map neurite density. With CODIVIDE, we found high levels of microscopic anisotropy in white matter

  4. Whole-body MRI, dynamic contrast-enhanced MRI, and diffusion-weighted imaging for the staging of multiple myeloma

    Energy Technology Data Exchange (ETDEWEB)

    Dutoit, Julie C.; Verstraete, Koenraad L. [Ghent University Hospital, Department of Radiology, Ghent (Belgium)

    2017-06-15

    Magnetic resonance imaging (MRI) is the most sensitive imaging technique for the detection of bone marrow infiltration, and has therefore recently been included in the new diagnostic myeloma criteria, as proposed by the International Myeloma Working Group. Nevertheless, conventional MRI only provides anatomical information and is therefore only of limited use in the response assessment of patients with multiple myeloma. The additional information from functional MRI techniques, such as diffusion-weighted imaging and dynamic contrast-enhanced MRI, can improve the detection rate of bone marrow infiltration and the assessment of response. This can further enhance the sensitivity and specificity of MRI in the staging of multiple myeloma patients. This article provides an overview of the technical aspects of conventional and functional MRI techniques with practical recommendations. It reviews the diagnostic performance, prognostic value, and role in therapy assessment in multiple myeloma and its precursor stages. (orig.)

  5. Diffusion-weighted imaging in the evaluation of watershed hypoxic-ischemic brain injury in pediatric patients

    Energy Technology Data Exchange (ETDEWEB)

    Liu, A.Y.; Zimmerman, R.A.; Haselgrove, J.C.; Bilaniuk, L.T.; Hunter, J.V. [Hospital of the Univ. of Pennsylvania (HUP), Philadelphia (United States). Dept. of Radiology

    2001-11-01

    The purpose of our study was to determine the usefulness of echo-planar diffusion-weighted imaging (EPDI) in the evaluation of watershed hypoxic-ischemic brain injury in pediatric patients. Eighteen patients ranging in age from 3 weeks to 12 years were evaluated for evidence of ischemic/infarction changes on conventional MR and EPDI. Included in the study group were five patients with sickle cell disease, four with congenital heart disease, four with hypotensive episodes with various etiologies, three with sepsis, and two with encephalitis or meningitis. Patients were examined 2 h to 6 days after the initial insult, with follow-up studies in four patients at 1 to 62 days after the initial examination. After conventional MR imaging (T1, FSE T2, and FLAIR), diffusion-weighted MR imaging was performed using high-speed, single-shot EP techniques with TR 6000, TE 144, matrix 96 x 128, FOV 23.3 x 31 and five b values of 0, 160, 360, 640, and 1,000 s/mm{sup 2}. EPDI demonstrated abnormally increased signal in watershed ischemic/infarction zones in all initial cases. Apparent diffusion coefficients (ADC) were obtained in 59 lesions. When compared with radiographically normal (on EPDI) contralateral brain parenchyma, 45 demonstrated a relatively decreased ADC, while eight had normal ({+-} 10 %) and six had increased ADC. In four cases, signal abnormalities on EPDI were not seen or exceeded that seen with conventional MR imaging. In the remaining cases, signal abnormalities were obvious on EPDI and more subtle on conventional MR imaging. Follow-up studies demonstrated resolution of abnormal EPDI signal with persistent abnormalities on conventional imaging in some cases, while others revealed an increase in size or number of EPDI signal abnormalities, suggesting ongoing acute ischemic/infarctive changes. EPDI is a rapid, sensitive technique for detecting watershed ischemic/infarction changes in pediatric patients with hypoperfusion episodes, at times before such changes are

  6. Phase-aligned multiple spin-echo averaging: a simple way to improve signal-to-noise ratio of in vivo mouse spinal cord diffusion tensor image.

    Science.gov (United States)

    Tu, Tsang-Wei; Budde, Matthew D; Xie, Mingqiang; Chen, Ying-Jr; Wang, Qing; Quirk, James D; Song, Sheng-Kwei

    2014-12-01

    To improve signal-noise-ratio of in vivo mouse spinal cord diffusion tensor imaging using-phase aligned multiple spin-echo technique. In vivo mouse spinal cord diffusion tensor imaging maps generated by multiple spin-echo and conventional spin-echo diffusion weighting were examined to demonstrate the efficacy of multiple spin-echo diffusion sequence to improve image quality and throughput. Effects of signal averaging using complex, magnitude and phased images from multiple spin-echo diffusion weighting were also assessed. Bayesian probability theory was used to generate phased images by moving the coherent signals to the real channel to eliminate the effect of phase variation between echoes while preserving the Gaussian noise distribution. Signal averaging of phased multiple spin-echo images potentially solves both the phase incoherence problem and the bias of the elevated Rician noise distribution in magnitude image. The proposed signal averaging with Bayesian phase-aligned multiple spin-echo images approach was compared to the conventional spin-echo data acquired with doubling the scan time. The diffusion tensor imaging parameters were compared in the mouse contusion spinal cord injury. Significance level (p-value) and effect size (Cohen's d) were reported between the control and contused spinal cord to inspect the sensitivity of each approach in detecting white matter pathology. Compared to the spin-echo image, the signal-noise-ratio increased to 1.84-fold using the phased image averaging and to 1.30-fold using magnitude image averaging in the spinal cord white matter. Multiple spin-echo phased image averaging showed improved image quality of the mouse spinal cord among the tested methods. Diffusion tensor imaging metrics obtained from multiple spin-echo phased images using three echoes and two averages closely agreed with those derived by spin-echo magnitude data with four averages (two times more in acquisition time). The phased image averaging correctly

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

    Energy Technology Data Exchange (ETDEWEB)

    Ferraz-Filho, Jose R.L.; Muniz, Marcos P.; Souza, Antonio S. [Medical School in Sao Jose do Rio Preto (FAMERP), Radiology Department, Sao Paulo (Brazil); Rocha, Antonio J. da [School Medical Sciences of the Santa Casa de Sao Paulo, Radiology Department, Sao Paulo (Brazil); Goloni-Bertollo, Eny M.; Pavarino-Bertelli, Erika C. [Center of Research and attendace in Neurofibromatosis (CEPAN) of Medical School in Sao Jose do Rio Preto (FAMERP), Sao Paulo (Brazil)

    2012-04-15

    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.)

  8. Diffusion tensor imaging for long-term follow-up of corticospinal tract degeneration in amyotrophic lateral sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, S.; Ehrenreich, H. [Max-Planck-Institute for Experimental Medicine, Georg-August-University, Hermann-Rein-Strasse 3, 37075, Goettingen (Germany); Departments of Neurology and Psychiatry, Georg-August-University, Goettingen (Germany); Finsterbusch, J.; Frahm, J. [Biomedizinische NMR Forschungs GmbH, Max-Planck-Institute for Biophysical Chemistry, Georg-August-University, Goettingen (Germany); Weishaupt, J.H. [Departments of Neurology and Psychiatry, Georg-August-University, Goettingen (Germany); Khorram-Sefat, D. [Department of Neuroradiology, Georg-August-University, Goettingen (Germany)

    2003-09-01

    Amyotrophic lateral sclerosis (ALS) is a predominantly clinical and electromyographic diagnosis. Conventional MRI reveals atrophy of the motor system, particularly the pyramidal tract, in the advanced stages but does not provide a sensitive measure of disease progression. Three patients with different principal symptoms of ALS, i.e., with predominant involvement of the upper (UMN) or lower (UMN) motor neurons, or bulbar disease, respectively, underwent serial clinical examination including lung function tests, conventional MRI, and diffusion tensor imaging (DTI). MRI demonstrated changes in of the pyramidal tract without measurable variation on follow-up. The patient with UMN involvement showed remarkable progressive loss of diffusion anisotropy in the pyramidal tract. DTI might be useful, together with clinical follow-up, as an objective morphological marker in therapeutic trials. (orig.)

  9. Long-Term Follow-up of a Patient with Traumatic Brain Injury Using Diffusion Tensor Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Skoglund, T.S.; Nilsson, D.; Ljungberg, M.; Joensson, L.; Rydenhag, B. (Dept. of Neurosurgery, Dept. of Medical Physics and Biomedical Engineering, and Dept. of Radiology, Sahlgrenska Univ. Hospital, Goeteborg (Sweden))

    2008-02-15

    This case report describes a patient who sustained severe head trauma with diffuse axonal injury (DAI). Examination with magnetic resonance diffusion tensor imaging (MR-DTI), 6 days post-injury, showed a severe reduction in fractional anisotropy (FA) in the rostral pons containing the corticospinal tract, which correlated to the patient's severe hemiparesis. By 18 months post-accident, the patient had recovered completely and conventional MRI showed no pathology. However, although her FA values in the rostral pons had increased, they were still not normalized. It seems that a complete normalization of the FA values is not required to achieve clinical recovery, and that MR-DTI seems to be more sensitive to DAI compared to conventional MRI

  10. Diffusion Tensor Imaging Of the Brain in Type 1 Diabetes

    Directory of Open Access Journals (Sweden)

    Jo Ann V. Antenor-Dorsey

    2014-10-01

    Full Text Available Individuals with Type 1 diabetes mellitus (T1DM are required to carefully manage their insulin dosing, dietary intake, and activity levels in order to maintain optimal blood sugar levels. Over time, exposure to hyperglycaemia is known to cause significant damage to the peripheral nervous system, but its impact on the central nervous system has been less well studied. Researchers have begun to explore the cumulative impact of commonly experienced blood glucose fluctuations on brain structure and function in patient populations. To date, these studies have typically used magnetic resonance imaging to measure regional grey and white matter volumes across the brain. However, newer methods, such as diffusion tensor imaging (DTI can measure the microstructural properties of white matter, which can be more sensitive to neurological effects than standard volumetric measures. Studies are beginning to use DTI to understand the impact of T1DM on white matter structure in the human brain. This work, its implications, future directions, and important caveats, are the focus of this review.

  11. Diffusion-weighted imaging in acute bacterial meningitis in infancy

    Energy Technology Data Exchange (ETDEWEB)

    Jan, W.; Zimmerman, R.A.; Bilaniuk, L.T.; Hunter, J.V.; Simon, E.M.; Haselgrove, J. [Department of Radiology, Children' s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, PA 19104, Philadelphia (United States)

    2003-09-01

    Bacterial meningitis is frequently fatal or leads to severe neurological impairment. Complications such as vasculitis, resulting in infarcts, should be anticipated and dealt with promptly. Our aim was to demonstrate the complications of meningitis by diffusion weighted imaging (DWI) in patients who deteriorated despite therapy. We studied 13 infants between the ages of 1 day and 32 months who presented with symptoms ranging from fever and vomiting to seizures, encephalopathy and coma due to bacterial meningitis, performing MRI, including DWI, 2-5 days after presentation. Multiple infarcts were found on DWI in 12 of the 13, most commonly in the frontal lobes (in 10). Global involvement was seen in four children, three of whom died; the fourth had a very poor outcome. In one case abnormalities on DWI were due to subdural empyemas. We diagnosed vasculitis in three of five patients studied with MRA. We think DWI an important part of an MRI study in infants with meningitis. Small cortical or deep white-matter infarcts due to septic vasculitis can lead to tissue damage not easily recognized on routine imaging and DWI can be used to confirm that extra-axial collections represent empyemas. (orig.)

  12. Corticospinal tract degeneration and possible pathogenesis in ALS evaluated by MR diffusion tensor imaging

    DEFF Research Database (Denmark)

    Karlsborg, Merete; Rosenbaum, Sverre; Wiegell, Mette R.;

    2004-01-01

    BACKGROUND: MR diffusion tensor imaging (DTI) appears to be a powerful method to investigate the neuronal and axonal fibre distribution in the human brain. Changes in diffusion characteristics of water molecules in the white matter can be estimated as the apparent diffusion coefficient (ADC) and ...

  13. Corticospinal tract degeneration and possible pathogenesis in ALS evaluated by MR diffusion tensor imaging

    DEFF Research Database (Denmark)

    Karlsborg, Merete; Rosenbaum, Sverre; Wiegell, Mette R.

    2004-01-01

    BACKGROUND: MR diffusion tensor imaging (DTI) appears to be a powerful method to investigate the neuronal and axonal fibre distribution in the human brain. Changes in diffusion characteristics of water molecules in the white matter can be estimated as the apparent diffusion coefficient (ADC) and ...

  14. Diffusion coefficients of water in biobased hydrogel polymer matrices by nuclear magnetic resonance imaging

    Science.gov (United States)

    The diffusion coefficient of water in biobased hydrogels were measured utilizing a simple NMR method. This method tracks the migration of deuterium oxide through imaging data that is fit to a diffusion equation. The results show that a 5 wt% soybean oil based hydrogel gives aqueous diffusion of 1.37...

  15. Corticospinal tract degeneration and possible pathogenesis in ALS evaluated by MR diffusion tensor imaging

    DEFF Research Database (Denmark)

    Karlsborg, Merete; Rosenbaum, Sverre; Wiegell, Mette R.;

    2004-01-01

    BACKGROUND: MR diffusion tensor imaging (DTI) appears to be a powerful method to investigate the neuronal and axonal fibre distribution in the human brain. Changes in diffusion characteristics of water molecules in the white matter can be estimated as the apparent diffusion coefficient (ADC...

  16. Diffusion and Perfusion MR Imaging in Acute Stroke: Clinical Utility and Potential Limitations for Treatment Selection

    DEFF Research Database (Denmark)

    Bateman, Mathew; Slater, Lee-Anne; Leslie-Mazwi, Thabele M

    2017-01-01

    Magnetic resonance (MR) diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) offer unique insight into acute ischemic stroke pathophysiology. These techniques may offer the ability to apply pathophysiology to accurately individualize acute stroke reperfusion treatment, including ...

  17. Diffusion weighted imaging and estimation of prognosis using apparent diffusion coefficient measurements in ischemic stroke

    Energy Technology Data Exchange (ETDEWEB)

    Gonen, Korcan Aysun, E-mail: aysunbalc@yahoo.com [Department of Radiology, State Hospital, Eski Cami district, Hastane street, N:1, 59300, Tekirdag (Turkey); Simsek, Mehmet Masum, E-mail: radyoloji@haydapasanumune.gov.tr [Department of Radiology, Haydarpasa Numune Training and Research Hospital, Tibbiye street, Uskudar 34200, Istanbul (Turkey)

    2010-11-15

    Objective: Estimation of the prognosis of infarction by using diffusion weighted imaging (DWI) and quantitative apparent diffusion coefficient (ADC) measurements. Methods: 23 patients having acute stroke symptoms with verified infarction in magnetic resonance imaging (MRI) were included in this study. Their MRI studies were performed between 6 and 12 h after the onset of their symptoms and were repeated on the fifth day. The infarction volumes were calculated by using DWI and the patients were divided into two groups as the ones having an expansion in the infarction area (group 1, n = 16) and the others having no expansion in the infarction area (group 2, n = 7). Quantitative ADC values were estimated. The groups were compared in terms of the ADC values on ADC maps obtained from DWI, performed during the between 6 and 12 h from the onset of the symptoms, referring to the core of the infarction (ADC{sub IC}), ischemic penumbra (ADC{sub P}) and the nonischemic parenchymal tissue (ADC{sub N}). P values < 0.05 were accepted to be statistically significant. Results: During the between 6 and 12 h mean infarction volume calculated by DWI was 23.3 cm{sup 3} for group 1 patients (ranging from 1.1 to 68.6) and this was found to be 40.3 cm{sup 3} (ranging from 1.8 to 91.5) on the fifth day. For the group 2 patients these values were found to be 42.1 cm{sup 3} (ranging from 1 to 94.7) and 41.9 (ranging from 1 to 94.7) for the same intervals respectively. A significant statistical result was failed to be demonstrated between the mean ADC{sub IC} and ADC{sub N} values (p = 0.350 and p = 0.229 respectively). However the comparison of the ADC{sub P} values between the groups was found to be highly significant (p < 0.001). When the differences between the ADC{sub P} and ADC{sub IC} and ADC{sub N} and ADC{sub P} were compared the results proved to be statistically significant (p = 0.038 and p < 0.001 respectively). Conclusions: We believe that ADC results that would be obtained from

  18. 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.)

  19. Prognostic Value of Brain Diffusion Weighted Imaging After Cardiac Arrest

    Science.gov (United States)

    Wijman, Christine A.C.; Mlynash, Michael; Caulfield, Anna Finley; Hsia, Amie W.; Eyngorn, Irina; Bammer, Roland; Fischbein, Nancy; Albers, Gregory W.; Moseley, Michael

    2009-01-01

    Objective Outcome prediction is challenging in comatose post-cardiac arrest survivors. We assessed the feasibility and prognostic utility of brain diffusion-weighted MRI (DWI) during the first week. Methods Consecutive comatose post-cardiac arrest patients were prospectively enrolled. MRI data of patients who met predefined specific prognostic criteria were used to determine distinguishing ADC thresholds. Group 1: death at 6 months and absent motor response or absent pupillary reflexes or bilateral absent cortical responses at 72 hours, or vegetative at 1 month. Group 2A: Glasgow outcome scale (GOS) score of 4 or 5 at 6 months. Group 2B: GOS of 3 at 6 months. The percentage of voxels below different apparent diffusion coefficient (ADC) thresholds was calculated at 50 × 10−6 mm2/sec intervals. Results Overall, 86% of patients underwent MR imaging. Fifty-one patients with 62 brain MRIs were included in the analyses. Forty patients met the specific prognostic criteria. The percentage of brain volume with an ADC value below 650–700 × 10−6 mm2/sec best differentiated between group 1 and groups 2A and 2B combined (p<0.001), while the 400–450 × 10−6 mm2/sec threshold best differentiated between groups 2A and 2B (p=0.003). The ideal time window for prognostication using DWI was between 49 to 108 hours after the arrest. When comparing MRI in this time window with the 72 hour neurological examination MRI improved the sensitivity for predicting poor outcome by 38% while maintaining 100% specificity (p=0.021). Interpretation Quantitative DWI in comatose post-cardiac arrest survivors holds great promise as a prognostic adjunct. PMID:19399889

  20. Imaging of inflammation by PET, conventional scintigraphy, and other imaging techniques.

    NARCIS (Netherlands)

    Gotthardt, M.; Bleeker-Rovers, C.P.; Boerman, O.C.; Oyen, W.J.G.

    2010-01-01

    Nuclear medicine imaging procedures play an important role in the assessment of inflammatory diseases. With the advent of 3-dimensional anatomic imaging, there has been a tendency to replace traditional planar scintigraphy by CT or MRI. Furthermore, scintigraphic techniques may have to be combined

  1. Imaging of Inflammation by PET, Conventional Scintigraphy, and Other Imaging Techniques

    NARCIS (Netherlands)

    Gotthardt, M.; Bleeker-Rovers, C.P.; Boerman, O.C.; Oyen, W.J.G.

    2013-01-01

    Nuclear medicine imaging procedures play an important role in the assessment of inflammatory diseases. With the advent of 3-dimensional anatomic imaging, there has been a tendency to replace traditional planar scintigraphy by CT or MRI. Furthermore, scintigraphic techniques may have to be combined

  2. Imaging of Inflammation by PET, Conventional Scintigraphy, and Other Imaging Techniques

    NARCIS (Netherlands)

    Gotthardt, M.; Bleeker-Rovers, C.P.; Boerman, O.C.; Oyen, W.J.G.

    2013-01-01

    Nuclear medicine imaging procedures play an important role in the assessment of inflammatory diseases. With the advent of 3-dimensional anatomic imaging, there has been a tendency to replace traditional planar scintigraphy by CT or MRI. Furthermore, scintigraphic techniques may have to be combined w

  3. Four-dimensional (4D) image reconstruction strategies in dynamic PET: beyond conventional independent frame reconstruction.

    Science.gov (United States)

    Rahmim, Arman; Tang, Jing; Zaidi, Habib

    2009-08-01

    In this article, the authors review novel techniques in the emerging field of spatiotemporal four-dimensional (4D) positron emission tomography (PET) image reconstruction. The conventional approach to dynamic PET imaging, involving independent reconstruction of individual PET frames, can suffer from limited temporal resolution, high noise (especially when higher frame sampling is introduced to better capture fast dynamics), as well as complex reconstructed image noise distributions that can be very difficult and time consuming to model in kinetic parameter estimation tasks. Various approaches that seek to address some or all of these limitations are described, including techniques that utilize (a) iterative temporal smoothing, (b) advanced temporal basis functions, (c) principal components transformation of the dynamic data, (d) wavelet-based techniques, as well as (e) direct kinetic parameter estimation methods. Future opportunities and challenges with regards to the adoption of 4D and higher dimensional image reconstruction techniques are also outlined.

  4. Initial study of magnetic resonance diffusion tensor imaging in brain white matter of early AIDS patients

    Institute of Scientific and Technical Information of China (English)

    XUAN Ang; WANG Guang-bin; SHI Da-peng; XU Jun-ling; LI Yong-li

    2013-01-01

    Background HIV is a neurotropic virus which can cause brain white matter demyelination,gliosis,and other pathological changes that appear as H IV encephalitis or AIDS dementia.The purpose of this study was to investigate the change of the diffused condition of water molecules in brain white matter in early acquired immune deficiency syndrome (AIDS) patients using MR diffusion tensor imaging (DTI).Methods DTI examinations were performed on a Siemens 3.0T MR scanner in 23 AIDS patients with normal brain appearance by conventional MRI and 20 healthy volunteers as the control group.Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were measured in nine regions; corpus callosum (CC) knee,CC body,CC splenium,periventricular white matter,frontal lobe white matter,parietal lobe white matter,occipital lobe white matter,and the anterior and posterior limbs of the internal capsule.The mean FA and ADC values from each region were compared in three groups:the symptomatic,asymptomatic and the control.Results The mean FA values were significantly lower and the mean ADC values were significantly higher in all nine regions in patients in the symptomatic group than in the asymptomatic and control group patients.In the asymptomatic group,the mean FA values were significantly lower and the mean ADC values were significantly higher at the CC knee,CC body,CC splenium,periventricular white matter,frontal lobe white matter and parietal lobe white matter,than in the control group.There were no significant differences at other regions between the two groups.Conclusions The diffused changes of water molecules in brain white matter in AIDS patients are related to brain white matter regions.DTI examination can detect the brain white matter lesions early in AIDS patients.

  5. Holographic imaging through a scattering medium by diffuser-aided statistical averaging.

    Science.gov (United States)

    Purcell, Michael J; Kumar, Manish; Rand, Stephen C; Lakshminarayanan, Vasudevan

    2016-07-01

    We introduce a practical digital holographic method capable of imaging through a diffusive or scattering medium. The method relies on statistical averaging from a rotating ground glass diffuser to negate the adverse effects caused by speckle introduced by a static diffuser or scattering medium. In particular, a setup based on Fourier transform holography is used to show that an image can be recovered after scattering by introducing an additional diffuser in the optical setup. This method is capable of recovering object information from behind a scattering layer in biomedical or military imaging applications.

  6. Holographic imaging through a scattering medium by diffuser-aided statistical averaging

    CERN Document Server

    Purcell, Michael J; Rand, Stephen C; Lakshminarayanan, Vasudevan

    2016-01-01

    We introduce a practical digital holographic method capable of imaging through a diffusive or scattering medium. The method relies on statistical averaging from a rotating ground glass diffuser to negate the adverse effects caused by speckle introduced by a first, static diffuser or scattering medium. In particular, a setup based on Fourier transform holography is used to show that an image can be recovered after scattering by introducing an additional diffuser in the optical setup. This method is capable of recovering object information from behind a scattering layer in biomedical or military imaging applications.

  7. Diffusion-weighted MR images and pineoblastoma. Diagnosis and follow-up

    Energy Technology Data Exchange (ETDEWEB)

    Gasparetto, Emerson L.; Cruz Junior, L. Celso Hygino; Doring, Thomas M.; Domingues, Romeu C. [Clinica de Diagnostico por Imagem (CDPI), Rio de Janeiro, RJ (Brazil)]. E-mail: egasparetto@gmail.com; Araujo, Bertha; Dantas, Mario Alberto [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Faculdade de Medicina. Dept. of Radiology; Chimelli, Leila [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Faculdade de Medicina. Dept. of Pathology

    2008-07-01

    Pineoblastomas are uncommon pineal tumors, which demonstrate rapid growing and poor prognosis. We report the case of a 43-year-old man with an enhancing pineal region mass, which showed restriction of the diffusion on diffusion-weighted (DW) MR images. The surgical biopsy defined the diagnosis of pineoblastoma and the therapy was initiated with radiation and chemotherapy. Three months later, the follow-up MR imaging showed areas suggestive of necrosis and the DW images demonstrate no significant areas of restricted diffusion. The differential diagnosis of pineal region masses that could show restriction of diffusion is discussed. (author)

  8. Determination of fat and total protein content in milk using conventional digital imaging

    DEFF Research Database (Denmark)

    Kucheryavskiy, Sergey; Melenteva, Anastasiia; Bogomolov, Andrey

    2014-01-01

    The applicability of conventional digital imaging to quantitative determination of fat and total protein in cow’s milk, based on the phenomenon of light scatter, has been proved. A new algorithm for extracting features from digital images of milk samples has been developed. The algorithm takes...... with cross-validated R2=0.890 for fat content and R2=0.720 for protein content). The results have been compared with previously published Vis/SW-NIR spectroscopic study of similar samples....

  9. Correlations between functional imaging markers derived from PET/CT and diffusion-weighted MRI in diffuse large B-cell lymphoma and follicular lymphoma.

    Directory of Open Access Journals (Sweden)

    Xingchen Wu

    Full Text Available OBJECTIVES: To investigate the correlations between functional imaging markers derived from positron emission tomography/computed tomography (PET/CT and diffusion-weighted magnetic resonance imaging (DWI in diffuse large B-cell lymphoma (DLBCL and follicular lymphoma (FL. Further to compare the usefulness of these tumor markers in differentiating diagnosis of the two common types of Non-Hodgkin's lymphoma (NHL. MATERIALS AND METHODS: Thirty-four consecutive pre-therapy adult patients with proven NHL (23 DLBCL and 11 FL underwent PET/CT and MRI examinations and laboratory tests. The maximum standardized uptake value (SUV(max, metabolic tumor volume (MTV, and metabolic tumor burden (MTB were determined from the PET/CT images. DWI was performed in addition to conventional MRI sequences using two b values (0 and 800 s/mm(2. The minimum and mean apparent diffusion coefficient (ADC(min and ADC(mean were measured on the parametric ADC maps. RESULTS: The SUV(max correlated inversely with the ADC(min (r =  -0.35, p<0.05. The ADC(min, ADC(mean, serum thymidine kinase (TK, Beta 2-microglobulin (B2m, lactate dehydrogenase (LD, and C-reactive protein (CRP correlated with both whole-body MTV and whole-body MTB (p<0.05 or 0.01. The SUV(max, TK, LD, and CRP were significantly higher in the DLBCL group than in the FL group. Receiver operating characteristic curve analysis showed that they were reasonable predictors in differentiating DLBCL from FL. CONCLUSIONS: The functional imaging markers determined from PET/CT and DWI are associated, and the SUV(max is superior to the ADC(min in differentiating DLBCL from FL. All the measured serum markers are associated with functional imaging markers. Serum LD, TK, and CRP are useful in differentiating DLBCL from FL.

  10. Wide-field quantitative imaging of tissue microstructure using sub-diffuse spatial frequency domain imaging.

    Science.gov (United States)

    McClatchy, David M; Rizzo, Elizabeth J; Wells, Wendy A; Cheney, Philip P; Hwang, Jeeseong C; Paulsen, Keith D; Pogue, Brian W; Kanick, Stephen C

    2016-06-20

    Localized measurements of scattering in biological tissue provide sensitivity to microstructural morphology but have limited utility to wide-field applications, such as surgical guidance. This study introduces sub-diffusive spatial frequency domain imaging (sd-SFDI), which uses high spatial frequency illumination to achieve wide-field sampling of localized reflectances. Model-based inversion recovers macroscopic variations in the reduced scattering coefficient [Formula: see text] and the phase function backscatter parameter (γ). Measurements in optical phantoms show quantitative imaging of user-tuned phase-function-based contrast with accurate decoupling of parameters that define both the density and the size-scale distribution of scatterers. Measurements of fresh ex vivo breast tissue samples revealed, for the first time, unique clustering of sub-diffusive scattering properties for different tissue types. The results support that sd-SFDI provides maps of microscopic structural biomarkers that cannot be obtained with diffuse wide-field imaging and characterizes spatial variations not resolved by point-based optical sampling.

  11. 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…

  12. Clinical Value of Whole-body Magnetic Resonance Diffusion Weighted Imaging on Detection of Malignant Metastases

    Institute of Scientific and Technical Information of China (English)

    Cheng Li; Zhen-sheng Liu; Xian-mao Du; Ling He; Jian Chen; Wei Wang; Fei Sun; Fang Du; Zhi-gang Luo; Zhen-long Xue; Yi Zhao; Chang-wu Zhou

    2009-01-01

    To evaluate the value of whole-body diffusion weighted imaging (WB-DWI) on detection of malignant metastasis.Methods Forty-six patients with malignant tumors underwent WB-DWI examinations between April 2007 and August 2007 in our hospital. Before WB-DWI examination, the primary cancers of all the patients were confirmed by pathology, and the TNM-stage was assessed with conventional magnetic resonance imaging (MRI) or computed tomography (CT). WB-DWl was performed using short TI inversion recovery echo-planar imaging (STIR-EPI) sequence. Abnormal high signal intensities on WB-DWI were considered as metastases. The results of WB-DWI were compared with other imaging modalities. For the assessment of the diagnostic capability of WB-DWl, WB-DWI were compared with CT for demonstrating mediastinal lymph node metastases and lung metastases, and with conventional MRI for demonstrating metastases in other locations.Results WB-DWI demonstrated 143 focuses, 14 of which were diagnosed to he benign lesions in routine imaging. The number of bone metastases depicted on WB-DWI and routine imaging was 85 and 86; lymph node metastases was 17 and 18; liver metastases was 14 and 14; lung metastases was 4 and 8; and brain metastases was 6 and 8, respectively. WB-DWI failed to detect 12 metastatic lesions including 3 osteoplastic bone metastases, 4 lung metastases, 3 mediastinal lymph node metastases, and 2 brain metastases. Four metastatic lesions including 2 deltopectoral lymph nodes and 2 rib metastases were detected with WB-DWI alone, all of which evolved greatly during clinical follow-up for more than 6 months. WB-DWI had higher detection rates for metastatic lesions in liver, bone, and lymph nodes than those in lung and brain (X2=30, P<0.001).Conclusions WB-DWI could detect most of metastatic lesions that were diagnosed with conventional MRI and CT. The limitations of WB-DWI might be had high false-positive rate and low efficiency in detecting mediastinal lymph node, brain, and

  13. MR diffusion-weighed imaging of rabbit liver

    Institute of Scientific and Technical Information of China (English)

    You-Hong Yuan; En-Hua Xiao; Zhong He; Jun Xiang; Ke-Li Tang; Rong-Hua Yan; Ke Jin; Zi-Wen Peng

    2005-01-01

    AIM: To study the techniques of MR diffusion-weighed imaging (DWI) for normal rabbit liver.METHODS: After 15 normal New Zealand white rabbits and one New Zealand white rabbit implanted with VX-2 tumor were anesthetized with 3% soluble pentobarbitone,DWI was performed respectively for different b values,repetition times (TR) or thicknesses, when other parameters were the same and magnetic resonance imaging (MRI)was performed respectively, or with different field of views (FOV) or coil when other parameters were the same. The distinction between groups was analyzed by SPSS10.0 with apparent diffusion coefficient (ADC), quality index (QI) or signal-noise ratio (SNR).RESULTS: As b value increased, liver ADC, QI and SNR of DWI became smaller and simultaneously (F= 292.87,156.1, 88.23, P<0.01). QI of DWI was high, when bvalue was 10, 50 or 100 respectively, but the distinction between them was insignificant; when b value was 800, QI and SNR of DWI were low. QI and SNR of DWI had no significant difference between TR = 4 000, 6 000 and 8 000. QI of DWI with 2 mm thickness was bigger than that with 5 mm thickness (t = 3.04, P<0.01), but SNR of DWI with 2 mm thickness was significantly smaller (t = -17.86, P<0.01).SNR of MRI with knee joint coil was obviously bigger than that with cranium coil [t = -5.77 (T1WI) or -4.02 (T2WI),P<0.01], but QI of MRI was smaller on the contrary [t = 7.10 (T1WI) or 3.97 (T2WI), P<0.01]. When FOV was enlarged gradually, SNR of MRI increased [F= 85.81 (T1WI) or 221.96 (T2WI), P<0.01], but QI firstly increased, then decreased [F= 68.67 (T1WI) or 69.46 (T2WI), P<0.01] and QI of MRI was the biggest when FOV was 20 cm×15 cm.CONCLUSION: The scanning technique is very important in DWI of rabbit liver and the overall quality of DWI with b (100 s/mm2), thickness (2 mm), cranium coils and FOV (20 cm× 15 cm) was best in our study, when other parameters were the same.

  14. Diffusion tensor imaging for Alzheimer's disease: A review of concepts and potential clinical applicability

    OpenAIRE

    Luciano de Gois Vasconcelos; Sonia Maria Dozzi Brucki; Andrea Parolin Jackowiski; Orlando Francisco Amodeo Bueno

    2009-01-01

    Abstract In view of the urgent need to identify an early and specific biomarker for Alzheimer's disease (AD), a PubMed database search was performed using the terms "Alzheimer disease" and "Diffusion Magnetic Resonance Imaging" to enable review of Diffusion tensor imaging (DTI) concepts and its potential clinical role in AD evaluation. Detailed analysis of selected abstracts showed that the main DTI measures, fractional anisotropy and apparent diffusion coefficient, indicators of fiber tract ...

  15. MR diffusion imaging and 1H spectroscopy in a child with medulloblastoma: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Wilke, M. [Max-Planck-Institute of Psychiatry, Muenchen (Germany). NMR Study Group; Eidenschink, A.; Mueller-Weihrich, S. [Technical Univ. of Muenchen, (Germany). Childrens' Hospital; Auer, D.P. [Max-Planck-Institute of Psychiatry, Muenchen (Germany). NMR Study Group

    2000-01-01

    We report on a child with a metastasising medulloblastoma which was assessed by MR diffusion imaging and 1H MR spectroscopy (MRS). Reduced mean apparent diffusion coefficients and a high amount of taurine could be demonstrated. This is the first reported case of high taurine in medulloblastoma in vivo and confirms earlier in vitro findings. It is suggested that the changes on diffusion imaging, possibly reflecting the small-cell histology of the tumour and high taurine in MRS, are indicative of medulloblastoma.

  16. Traumatic Brain Injury Diffusion Magnetic Resonance Imaging Research Roadmap Development Project

    Science.gov (United States)

    2010-10-01

    John M. [john.moreland@nist.gov] Tips and tricks for assessing diffusion MR data quality Alexander Leemans [Alexander@isi.uu.nl] Atlas-based...TBI are needed to support diagnosis and therapy and to predict TBI consequences while avoiding further injury. Diffusion magnetic resonance imaging...needed to support diagnosis and therapy and to predict TBI consequences while avoiding further injury. Diffusion magnetic resonance imaging has

  17. Coarctation of the aorta: comparison of aortic dimensions between conventional MR imaging, 3D MR angiography, and conventional angiography

    Energy Technology Data Exchange (ETDEWEB)

    Godart, Francois; Rey, Christian [Department of Paediatric Cardiology, Cardiac Hospital, University of Lille, 59037 Lille (France); Labrot, Gabrielle; McFadden, Eugene; Beregi, Jean-Paul [Department of Radiology, Cardiac Hospital, University of Lille, 59037 Lille (France); Devos, Patrick [CERIM-Department of Biostatistics, University of Lille, 59037 Lille (France)

    2002-08-01

    Magnetic resonance angiography is increasingly used as a non-invasive method in the evaluation of coarctation of the aorta. The aim of this study was to compare aortic dimensions calculated by MR angiography and those obtained by more conventional MR sequences and conventional angiography. Twenty-six consecutive patients with coarctation underwent three-dimensional MR angiography. Two independent observers retrospectively evaluated three aortic segments, site of coarctation, presence of aneurysm and existence of collateral circulation. Three aortic segments were also compared with those obtained on classical MR sequences and conventional angiography. The MR angiography was successfully performed in all showing 1 aneurysm and collateral circulation in 8 patients. Almost perfect intraobserver (r{sup 2}>0.91) and excellent interobserver (r{sup 2}>0.80) reliabilities were obtained for each aortic segment no matter which MR sequence was employed. Similarly, mainly excellent (r{sup 2}>0.80) concordance analysis was observed between MR angiography measurements and those calculated by either spin-echo/gradient-echo sequences or conventional angiography. This study demonstrates that MR angiography is a fast, accurate and reproducible method in the evaluation of coarctation of the aorta. It provides excellent anatomic information and reliably detects collateral vessels. Magnetic resonance angiography could probably replace the conventional angiography and will provide an additional diagnostic value in combination with turbo spin-echo sequence. (orig.)

  18. A Dosimetric Comparison between Conventional Fractionated and Hypofractionated Image-guided Radiation Therapies for Localized Prostate Cancer

    Institute of Scientific and Technical Information of China (English)

    Ming Li; Gao-Feng Li; Xiu-Yu Hou; Hong Gao; Yong-Gang Xu; Ting Zhao

    2016-01-01

    Background:Image-guided radiation therapy (IGRT) is the preferred method for curative treatment of localized prostate cancer,which could improve disease outcome and reduce normal tissue toxicity reaction.IGRT using cone-beam computed tomography (CBCT) in combination with volumetric-modulated arc therapy (VMAT) potentially allows smaller treatment margins and dose escalation to the prostate.The aim of this study was to compare the difference of dosimetric diffusion in conventional IGRT using 7-field,step-and-shoot intensity-modulated radiation therapy (IMRT) and hypofractionated IGRT using VMAT for patients with localized prostate cancer.Methods:We studied 24 patients who received 78 Gy in 39 daily fractions or 70 Gy in 28 daily fractions to their prostate with/without the seminal vesicles using IMRT (n =12) or VMAT (n =12) for prostate cancer between November 2013 and October 2015.Image guidance was performed using kilovoltage CBCT scans equipped on the linear accelerator.Offline planning was performed using the daily treatment images registered with simulation computed tomography (CT) images.A total of 212 IMRT plans in conventional cohort and 292 VMAT plans in hypofractionated cohort were enrolled in the study.Dose distributions were recalculated on CBCT images registered with the planning CT scanner.Results:Compared with 7-field,step-and-shoot IMRT,VMAT plans resulted in improved planning target volume (PTV) D95% (7663.17 ± 69.57 cGy vs.7789.17 ± 131.76 cGy,P < 0.001).VMAT reduced the rectal D25 (P < 0.001),D35 (P < 0.001),and D50 (P < 0.001),bladder V50 (P < 0.001),D25 (P =0.002),D35 (P =0.028),and D50 (P =0.029).However,VMAT did not statistically significantly reduce the rectal V50,compared with 7-field,step-and-shoot IMRT (25.02 ± 5.54% vs.27.43 ± 8.79%,P =0.087).Conclusions:To deliver the hypofractionated radiotherapy in prostate cancer,VMAT significantly increased PTV D95% dose and decreased the dose of radiation delivered to adjacent

  19. A Dosimetric Comparison between Conventional Fractionated and Hypofractionated Image-guided Radiation Therapies for Localized Prostate Cancer

    Science.gov (United States)

    Li, Ming; Li, Gao-Feng; Hou, Xiu-Yu; Gao, Hong; Xu, Yong-Gang; Zhao, Ting

    2016-01-01

    Background: Image-guided radiation therapy (IGRT) is the preferred method for curative treatment of localized prostate cancer, which could improve disease outcome and reduce normal tissue toxicity reaction. IGRT using cone-beam computed tomography (CBCT) in combination with volumetric-modulated arc therapy (VMAT) potentially allows smaller treatment margins and dose escalation to the prostate. The aim of this study was to compare the difference of dosimetric diffusion in conventional IGRT using 7-field, step-and-shoot intensity-modulated radiation therapy (IMRT) and hypofractionated IGRT using VMAT for patients with localized prostate cancer. Methods: We studied 24 patients who received 78 Gy in 39 daily fractions or 70 Gy in 28 daily fractions to their prostate with/without the seminal vesicles using IMRT (n = 12) or VMAT (n = 12) for prostate cancer between November 2013 and October 2015. Image guidance was performed using kilovoltage CBCT scans equipped on the linear accelerator. Offline planning was performed using the daily treatment images registered with simulation computed tomography (CT) images. A total of 212 IMRT plans in conventional cohort and 292 VMAT plans in hypofractionated cohort were enrolled in the study. Dose distributions were recalculated on CBCT images registered with the planning CT scanner. Results: Compared with 7-field, step-and-shoot IMRT, VMAT plans resulted in improved planning target volume (PTV) D95% (7663.17 ± 69.57 cGy vs. 7789.17 ± 131.76 cGy, P V50 (P statistically significantly reduce the rectal V50, compared with 7-field, step-and-shoot IMRT (25.02 ± 5.54% vs. 27.43 ± 8.79%, P = 0.087). Conclusions: To deliver the hypofractionated radiotherapy in prostate cancer, VMAT significantly increased PTV D95% dose and decreased the dose of radiation delivered to adjacent normal tissues comparing to 7-field, step-and-shoot IMRT. Daily online image-guidance and better management of bladder and rectum could make a more precise

  20. Visualization of the medial forebrain bundle using diffusion tensor imaging

    Directory of Open Access Journals (Sweden)

    Ardian eHana

    2015-10-01

    Full Text Available Diffusion tensor imaging is a technique that enables physicians the portrayal of white matter tracts in vivo. We used this technique in order to depict the medial forebrain bundle in 15 consecutive patients between 2012 and 2015. Men and women of all ages were included. There were 6 women and 9 men. The mean age was 58,6 years (39-77. Nine patients were candidates for an eventual deep brain stimulation. Eight of them suffered from Parkinson`s disease and one had multiple sclerosis. The remaining 6 patients suffered from different lesions which were situated in the frontal lobe. These were 2 metastasis, 2 meningiomas, 1 cerebral bleeding and 1 glioblastoma. We used a 3DT1-sequence for the navigation. Furthermore T2- and DTI- sequences were performed. The FOV was 200 x 200 mm², slice thickness 2 mm, and an acquisition matrix of 96 x 96 yielding nearly isotropic voxels of 2 x 2 x 2 mm. 3-Tesla-MRI was carried out strictly axial using 32 gradient directions and one b0-image. We used Echo-Planar-Imaging (EPI and ASSET parallel imaging with an acceleration factor of 2. b-value was 800 s/mm². The maximal angle was 50°. Additional scanning time was less than 9 minutes. We were able to visualize the medial forebrain bundle in 12 of our patients bilaterally and in the remaining 3 patients we depicted the medial forebrain bundle on one side. It was the contralateral side of the lesion. These were 2 meningiomas and one metastasis. Portrayal of the medial forebrain bundle is possible for everyday routine for neurosurgical interventions. As part of the reward circuitry it might be of substantial importance for neurosurgeons during deep brain stimulation in patients with psychiatric disorders. Furthermore it might explain at a certain extent character changes in patients with lesions in the frontal lobe. Surgery in this part of the brain should always take the preservation of this white matter tract into account.

  1. Technical advancements and protocol optimization of diffusion-weighted imaging (DWI) in liver.

    Science.gov (United States)

    Ni, Ping; Lin, Yuning; Zhong, Qun; Chen, Ziqian; Sandrasegaran, Kumar; Lin, Chen

    2016-01-01

    An area of rapid advancement in abdominal MRI is diffusion-weighted imaging (DWI). By measuring diffusion properties of water molecules, DWI is capable of non-invasively probing tissue properties and physiology at cellular and macromolecular level. The integration of DWI as part of abdominal MRI exam allows better lesion characterization and therefore more accurate initial diagnosis and treatment monitoring. One of the most technical challenging, but also most useful abdominal DWI applications is in liver and therefore requires special attention and careful optimization. In this article, the latest technical developments of DWI and its liver applications are reviewed with the explanations of the technical principles, recommendations of the imaging parameters, and examples of clinical applications. More advanced DWI techniques, including Intra-Voxel Incoherent Motion (IVIM) diffusion imaging, anomalous diffusion imaging, and Diffusion Kurtosis Imaging (DKI) are discussed.

  2. Better Visualization of Vermiform Appendix With Tissue Harmonic Imaging Compared to Conventional Sonography

    Science.gov (United States)

    Inal, Mikail; Unal, Birsen; Bilgili, Yasemin Karadeniz

    2014-01-01

    Background: Surgery of appendicitis carries 7-11% negative appendectomy rates. Sonographically visualized normal appendix precludes unnecessary computed tomography (CT) examination and may reduce negative appendectomy rates. Tissue harmonic imaging (THI) has been reported to improve the overall image quality. Objective: We aimed to assess whether THI is more successful than conventional ultrasonography (US) in detecting normal and pathologic appendices. Patients and Methods: The study was performed on 185 patients who applied for routine US examinations in whom clinical findings of appendicitis were detected in 25. We searched for the appendix; applying both THI and conventional US to each patient, one before and the other after the routine US examinations. Patients were divided into two groups; one was evaluated first with conventional US and the other first with THI. When the appendix was found, localization, diameter and time spent for visualization were recorded. Twelve patients were operated; all of whom had appendicitis pathologically. Two methods were compared for: 1. Success rates in all patients; female, male and child groups separately; 2. Visualization of pathologic and normal appendices; 3. Time for visualization of appendix; 4. Comparison of success rates in the adult and child population. The relationship between the rate of visualization and body mass index was evaluated. Results: The appendix was visualized better by THI in all patients, and in the female and male groups (P < 0.001). In children, both methods were more successful compared to adults (P < 0.001, compared to male group, P < 0.001, compared to female group), with no difference between the methods (P = 0.22). When only the normal appendices were concerned, there was significant difference between both methods (P < 0.000). Both methods detected pathologic appendices better than normal ones, with a higher ratio for THI (P = 0.022 for the THI group, and χ2 = 7.22, P = 0.07 for the

  3. Improving CT-guided transthoracic biopsy of mediastinal lesions by diffusion-weighted magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Marcos Duarte; TyngI, Chiang Cheng; Bitencourt, Almir Galvao Vieira; Gross, Jefferson Luiz; Zurstrassen, Charles Edouard, E-mail: marcosduarte500@gmail.com [AC Camargo Cancer Center, Sao Paulo, SP (Brazil); Hochhegger, Bruno [Universidade Federal de Ciencias da Saude de Porto Alegre (UFCSPA), RS (Brazil). Dept. de Radiologia; Benveniste, Marcelo Felipe Kuperman; Odisio, Bruno Calazans [University of Texas, MD Anderson Cancer Center, Houston, TX (United States); Marchiori, Edson [Universidade Federal do Rio de Janeiro (UFRJ), Petropolis, RJ (Brazil)

    2014-11-15

    Objectives: to evaluate the preliminary results obtained using diffusion-weighted magnetic resonance imaging and the apparent diffusion coefficient for planning computed tomography-guided biopsies of selected mediastinal lesions. Methods: eight patients with mediastinal lesions suspicious for malignancy were referred for computed tomography-guided biopsy. Diffusion-weighted magnetic resonance imaging and apparent diffusion coefficient measurement were performed to assist in biopsy planning with diffusion/computed tomography fused images. We selected mediastinal lesions that could provide discordant diagnoses depending on the biopsy site, including large heterogeneous masses, lesions associated with lung atelectasis or consolidation, lesions involving large mediastinal vessels and lesions for which the results of biopsy using other methods and histopathological examination were divergent from the clinical and radiological suspicion. Results: in all cases, the biopsy needle was successfully directed to areas of higher signal intensity on diffusion weighted sequences and the lowest apparent diffusion coefficient within the lesion (mean, 0.8 [range, 0.6–1.1]610{sup -3} mm{sup 2}/s), suggesting high cellularity. All biopsies provided adequate material for specific histopathological diagnoses of four lymphomas, two sarcomas and two thymoma s. Conclusion: functional imaging tools, such as diffusion-weighted imaging and the apparent diffusion coefficient, are promising for implementation in noninvasive and imaging-guided procedures. However, additional studies are needed to confirm that mediastinal biopsy can be improved with these techniques. (author)

  4. Diffusion-weighted imaging and proton MR spectroscopy in the characterization of acute disseminated encephalomyelitis

    Energy Technology Data Exchange (ETDEWEB)

    Balasubramanya, K.S.; Kovoor, J.M.E.; Jayakumar, P.N.; Ravishankar, S.; Kamble, R.B. [National Institute of Mental Health and Neurosciences, Department of Neuroimaging and Interventional Radiology, Bangalore, Karnataka (India); Panicker, J.; Nagaraja, D. [National Institute of Mental Health and Neurosciences, Department of Neurology, Bangalore (India)

    2007-02-15

    Acute disseminated encephalomyelitis (ADEM) is usually a monophasic illness characterized by multiple lesions involving gray and white matter. Quantitative MR techniques were used to characterize and stage these lesions. Eight patients (seven males and one female; mean age 19 years, range 5 to 36 years) were studied using conventional MRI (T2- and T1-weighted and FLAIR sequences), diffusion-weighted imaging (DWI) and proton magnetic resonance spectroscopy (MRS). Apparent diffusion coefficient (ADC) values and MRS ratios were calculated for the lesion and for normal-appearing white matter (NAWM). Three patients were imaged in the acute stage (within 7 days of the onset of neurological symptoms) and five in the subacute stage (after 7 days from the onset of symptoms). ADC values in NAWM were in the range 0.7-1.24 x 10{sup -3} mm/s{sup 2} (mean 0.937 {+-} 0.17 mm/s{sup 2}). ADC values of ADEM lesions in the acute stage were in the range 0.37-0.68 x 10{sup -3} mm/s{sup 2} (mean 0.56 {+-} 0.16 mm/s{sup 2}) and 1.01-1.31 x 10{sup -3} mm/s{sup 2} (mean 1.24 {+-} 0.13 mm/s{sup 2}) in the subacute stage. MRS ratios were obtained for all patients. NAA/Cho ratios were in the range 1.1-3.5 (mean 1.93 {+-} 0.86) in the NAWM. NAA/Cho ratios within ADEM lesions in the acute stage were in the range 0.63-1.48 (mean 1.18 {+-} 0.48) and 0.29-0.84 (mean 0.49 {+-} 0.22) in the subacute stage. The ADC values, NAA/Cho and Cho/Cr ratios were significantly different between lesions in the acute and subacute stages (P < 0.001, P < 0.027, P < 0.047, respectively). ADC values were significantly different between lesions in the acute (P < 0.009) and subacute stages (P < 0.005) with NAWM. In addition, NAA/Cho and Cho/Cr ratios were significantly different between lesions in the subacute stage and NAWM (P < 0.006, P < 0.007, respectively). ADEM lesions were characterized in the acute stage by restricted diffusion and in the subacute stage by free diffusion and a decrease in NAA/Cho ratios

  5. OPUS: optoacoustic imaging combined with conventional ultrasound for breast cancer detection

    Science.gov (United States)

    Haisch, C.; Zell, K.; Sperl, J. I.; Ketzer, S.; Vogel, M. W.; Menzenbach, P.; Niessner, R.

    2007-07-01

    Besides x-ray imaging, sonography is the most common method for breast cancer screening. The intention of our work is to develop optoacoustical imaging as an add-on to a conventional system. While ultrasound imaging reveals acoustical properties of tissue, optoacoustics generates an image of the distribution of optical absorption. Hence, it can be a valuable addition to sonography, because acoustical properties of different tissues show only a slight variation whereas the optical properties may differ strongly. Additionally, optoacoustics gives access to physiological parameters, like oxygen saturation of blood. For the presented work, we combine a conventional ultrasound system to a 100 Hz laser. The laser system consists of a Nd:YAG-laser at a wavelength of 532 nm with 7 ns pulse duration, coupled to a tunable Optical Parametric Oscillator (OPO) with a tuning rage from 680 nm to 2500 nm. The tunable laser source allows the selection of wavelengths which compromising high spectral information content with high skin transmission. The laser pulse is delivered fiber-optically to the ultrasound transducer and coupled into the acoustical field of view. Homogeneous illumination is crucial in order to achieve unblurred images. Furthermore the maximum allowed pulse intensities in accordance with standards for medical equipment have to be met to achieve a high signal to noise ration. The ultrasound instrument generates the trigger signal which controls the laser pulsing in order to apply ultrasound instrument's imaging procedures without major modifications to generate an optoacoustic image. Detection of the optoacoustic signal as well as of the classical ultrasound signal is carried out by the standard medical ultrasound transducer. The characterization of the system, including quantitative measurements, performed on tissue phantoms, is presented. These phantoms have been specially designed regarding their acoustical as well as their optical properties.

  6. Diffusion MR Imaging of Postoperative Bilateral Acute Ischemic Optic Neuropathy

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, Anusha; Srinivasan, Sivasubramanian [Khoo Teck Puat Hospital, Singapore (Singapore)

    2012-09-15

    We read with great interest, the case report on ischemic optic neuropathy (1). We would like to add a few points concerning the blood supply of the optic nerve and the correlation with the development of post-operative ischemic neuropathy. Actually, the perioperative or post-operative vision loss (postoperative ischemic neuropathy) is most likely due to ischemic optic neuropathy. Ischemic optic neuropathy (2) is classified as an anterior ischemic optic neuropathy (AION) and posterior ischemic optic neuropathy (PION). This classification is based on the fact that blood supply (2) to the anterior segment of the optic nerve (part of the optic nerve in the scleral canal and the optic disc) is supplied by short posterior ciliary vessels or anastamotic ring branches around the optic nerve. The posterior part of the optic canal is relatively less perfused, and is supplied by ophthalmic artery and central fibres are perfused by a central retinal artery. So, in the post-operative period, the posterior part of the optic nerve is more vulnerable for ischemia, especially, after major surgeries (3), one of the theories being hypotension or anaemia (2) and resultant decreased perfusion. The onset of PION is slower than the anterior ischemic optic neuropathy. AION on the other hand, is usually spontaneous (idiopathic) or due to arteritis, and is usually sudden in its onset. The reported case is most likely a case of PION. The role of imaging, especially the diffusion weighted magnetic resonance imaging, is very important because the ophthalmoscopic findings in early stages of PION is normal, and it may delay the diagnosis. On the other hand, edema of the disc is usually seen in the early stages of AION.

  7. Chronic Effects of Boxing: Diffusion Tensor Imaging and Cognitive Findings.

    Science.gov (United States)

    Wilde, Elisabeth A; Hunter, Jill V; Li, Xiaoqi; Amador, Cristian; Hanten, Gerri; Newsome, Mary R; Wu, Trevor C; McCauley, Stephen R; Vogt, Gregory S; Chu, Zili David; Biekman, Brian; Levin, Harvey S

    2016-04-01

    We used magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) to evaluate the effects of boxing on brain structure and cognition in 10 boxers (8 retired, 2 active; mean age = 45.7 years; standard deviation [SD] = 9.71) and 9 participants (mean age = 43.44; SD = 9.11) in noncombative sports. Evans Index (maximum width of the anterior horns of the lateral ventricles/maximal width of the internal diameter of the skull) was significantly larger in the boxers (F = 4.52; p = 0.050; Cohen's f = 0.531). Word list recall was impaired in the boxers (F(1,14) = 10.70; p = 0.006; f = 0.84), whereas implicit memory measured by faster reaction time (RT) to a repeating sequence of numbers than to a random sequence was preserved (t = 2.52; p boxing had the most consistent, negative correlations with FA, ranging from -0.65 for the right ventral striatum to -0.92 for the right cerebral peduncle. Years of boxing was negatively related to the number of words consistently recalled over trials (r = -0.74; p = 0.02), delayed recall (r = -0.83; p = 0.003), and serial RT (r = 0.66; p = 0.05). We conclude that microstructural integrity of white matter tracts is related to declarative memory and response speed in boxers and to the extent of boxing exposure. Implications for chronic traumatic encephalopathy are discussed.

  8. Diffusion tensor imaging reveals evolution of primate brain architectures.

    Science.gov (United States)

    Zhang, Degang; Guo, Lei; Zhu, Dajiang; Li, Kaiming; Li, Longchuan; Chen, Hanbo; Zhao, Qun; Hu, Xiaoping; Liu, Tianming

    2013-11-01

    Evolution of the brain has been an inherently interesting problem for centuries. Recent studies have indicated that neuroimaging is a powerful technique for studying brain evolution. In particular, a variety of reports have demonstrated that consistent white matter fiber connection patterns derived from diffusion tensor imaging (DTI) tractography reveal common brain architecture and are predictive of brain functions. In this paper, based on our recently discovered 358 dense individualized and common connectivity-based cortical landmarks (DICCCOL) defined by consistent fiber connection patterns in DTI datasets of human brains, we derived 65 DICCCOLs that are common in macaque monkey, chimpanzee and human brains and 175 DICCCOLs that exhibit significant discrepancies amongst these three primate species. Qualitative and quantitative evaluations not only demonstrated the consistencies of anatomical locations and structural fiber connection patterns of these 65 common DICCCOLs across three primates, suggesting an evolutionarily preserved common brain architecture but also revealed regional patterns of evolutionarily induced complexity and variability of those 175 discrepant DICCCOLs across the three species.

  9. Classification of Error-Diffused Halftone Images Based on Spectral Regression Kernel Discriminant Analysis

    Directory of Open Access Journals (Sweden)

    Zhigao Zeng

    2016-01-01

    Full Text Available This paper proposes a novel algorithm to solve the challenging problem of classifying error-diffused halftone images. We firstly design the class feature matrices, after extracting the image patches according to their statistics characteristics, to classify the error-diffused halftone images. Then, the spectral regression kernel discriminant analysis is used for feature dimension reduction. The error-diffused halftone images are finally classified using an idea similar to the nearest centroids classifier. As demonstrated by the experimental results, our method is fast and can achieve a high classification accuracy rate with an added benefit of robustness in tackling noise.

  10. Spatially selective 2D RF inner field of view (iFOV diffusion kurtosis imaging (DKI of the pediatric spinal cord

    Directory of Open Access Journals (Sweden)

    Chris J. Conklin

    2016-01-01

    Full Text Available Magnetic resonance based diffusion imaging has been gaining more utility and clinical relevance over the past decade. Using conventional echo planar techniques, it is possible to acquire and characterize water diffusion within the central nervous system (CNS; namely in the form of Diffusion Weighted Imaging (DWI and Diffusion Tensor Imaging (DTI. While each modality provides valuable clinical information in terms of the presence of diffusion and its directionality, both techniques are limited to assuming an ideal Gaussian distribution for water displacement with no intermolecular interactions. This assumption neglects pathological processes that are not Gaussian therefore reducing the amount of potentially clinically relevant information. Additions to the Gaussian distribution measured by the excess kurtosis, or peakedness, of the probabilistic model provide a better understanding of the underlying cellular structure. The objective of this work is to provide mathematical and experimental evidence that Diffusion Kurtosis Imaging (DKI can offer additional information about the micromolecular environment of the pediatric spinal cord. This is accomplished by a more thorough characterization of the nature of random water displacement within the cord. A novel DKI imaging sequence based on a tilted 2D spatially selective radio frequency pulse providing reduced field of view (FOV imaging was developed, implemented, and optimized on a 3 Tesla MRI scanner, and tested on pediatric subjects (healthy subjects: 15; patients with spinal cord injury (SCI:5. Software was developed and validated for post processing of the DKI images and estimation of the tensor parameters. The results show statistically significant differences in mean kurtosis (p < 0.01 and radial kurtosis (p < 0.01 between healthy subjects and subjects with SCI. DKI provides incremental and novel information over conventional diffusion acquisitions when coupled with higher order estimation

  11. Expanded image database of pistachio x-ray images and classification by conventional methods

    Science.gov (United States)

    Keagy, Pamela M.; Schatzki, Thomas F.; Le, Lan Chau; Casasent, David P.; Weber, David

    1996-12-01

    In order to develop sorting methods for insect damaged pistachio nuts, a large data set of pistachio x-ray images (6,759 nuts) was created. Both film and linescan sensor images were acquired, nuts dissected and internal conditions coded using the U.S. Grade standards and definitions for pistachios. A subset of 1199 good and 686 insect damaged nuts was used to calculate and test discriminant functions. Statistical parameters of image histograms were evaluated for inclusion by forward stepwise discrimination. Using three variables in the discriminant function, 89% of test set nuts were correctly identified. Comparable data for 6 human subjects ranged from 67 to 92%. If the loss of good nuts is held to 1% by requiring a high probability to discard a nut as insect damaged, approximately half of the insect damage present in clean pistachio nuts may be detected and removed by x-ray inspection.

  12. 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.

  13. Diffusion tensor imaging on white matter in normal adults and elderly patients with hypertension

    Institute of Scientific and Technical Information of China (English)

    HUANG Li; LING Xue-ying; LIU Si-run

    2006-01-01

    @@ Diffusion-weighted magnetic resonance imaging (MRI) exploits the properties of randomly moving water molecules in the presence of magnetic field gradients. Within tissue, diffusion of water molecules is restricted by cell membranes, small vessels, axon cylinders, membrane, chemical interactions of water and macromolecules. In the brain, water diffusion exhibits directionality in the orientation along the long axis of white matter. This is referred to as "diffusion anisotropy". Diffusion anisotropy can be measured via diffusion tensor imaging (DTI). There is a class of anisotropy indices that reflect the degree of anisotropy of water diffusion which are related to the degree of architectural and structural coherence within each voxel of the tissue. Fractional anisotropy (FA) was the most frequently used index of anisotropy.

  14. Design and Characterisation of Tissue-Mimicking Gel Phantoms for Diffusion Kurtosis Imaging

    CERN Document Server

    Portakal, Ziyafer Gizem; Spezi, Emiliano; Tuncel, Nina; Phillips, Jonathan

    2016-01-01

    The purpose of the study was to create tissue-mimicking gel phantoms appropriate for diffusion kurtosis imaging (DKI). Diffusion coefficients, including the well-known apparent diffusion coefficients (ADCs) and the diffusion coefficient based on the kurtosis model for the decay of the diffusion signal and (excess) kurtosis values were experimentally determined for the gelling agents of agar, agarose and polyvinyl alcohol (PVA) cryogel commonly used in multi-modal imaging. Although we observe an increase in kurtosis with the concentration of the gelling agents, the values obtained from diffusion-weighted magnetic resonance imaging (DW-MRI) were too low (under the expectations) to mimic the range of values reported in the literature for various healthy and diseased tissues. To create tissue-mimicking gels phantoms with more realistic kurtosis values, different concentrations of glass microbeads were added. Experimental characterisation showed that realistic kurtosis values for a range of tissues may be obtained...

  15. Application of Linearized Anisotropic Diffusion Equation to Edge-Preserving Image Smoothing

    Institute of Scientific and Technical Information of China (English)

    YUANZejian; ZHENGNanning; ZHANGYuanlin

    2004-01-01

    A stable anisotropic diffusion model for edge-preservlng image smoothing is presented. By comparison with existing diffusion models~ this model has two significant new features. The first is that the diffusion model has the ability to adjust the diffusion coefficient and to regulate diffusion orientation simultaneously. The second is that the diffusion model being nonlinear in essence is linearized along time coordinates which makes the model more stable and thus the complexity of computation is reduced greatly. We use an Additive operator splitting scheme (AOS) that is an efficient and stable numerical method to implement the edge-preservlng image smoothing. The experimental results show that the model proposed in this paper is not only stable and efficient but can preserve image edge.

  16. Development of a high angular resolution diffusion imaging human brain template.

    Science.gov (United States)

    Varentsova, Anna; Zhang, Shengwei; Arfanakis, Konstantinos

    2014-05-01

    Brain diffusion templates contain rich information about the microstructure of the brain, and are used as references in spatial normalization or in the development of brain atlases. The accuracy of diffusion templates constructed based on the diffusion tensor (DT) model is limited in regions with complex neuronal micro-architecture. High angular resolution diffusion imaging (HARDI) overcomes limitations of the DT model and is capable of resolving intravoxel heterogeneity. However, when HARDI is combined with multiple-shot sequences to minimize image artifacts, the scan time becomes inappropriate for human brain imaging. In this work, an artifact-free HARDI template of the human brain was developed from low angular resolution multiple-shot diffusion data. The resulting HARDI template was produced in ICBM-152 space based on Turboprop diffusion data, was shown to resolve complex neuronal micro-architecture in regions with intravoxel heterogeneity, and contained fiber orientation information consistent with known human brain anatomy.

  17. Variability of Image Features Computed from Conventional and Respiratory-Gated PET/CT Images of Lung Cancer

    Directory of Open Access Journals (Sweden)

    Jasmine A. Oliver

    2015-12-01

    Full Text Available Radiomics is being explored for potential applications in radiation therapy. How various imaging protocols affect quantitative image features is currently a highly active area of research. To assess the variability of image features derived from conventional [three-dimensional (3D] and respiratory-gated (RG positron emission tomography (PET/computed tomography (CT images of lung cancer patients, image features were computed from 23 lung cancer patients. Both protocols for each patient were acquired during the same imaging session. PET tumor volumes were segmented using an adaptive technique which accounted for background. CT tumor volumes were delineated with a commercial segmentation tool. Using RG PET images, the tumor center of mass motion, length, and rotation were calculated. Fifty-six image features were extracted from all images consisting of shape descriptors, first-order features, and second-order texture features. Overall, 26.6% and 26.2% of total features demonstrated less than 5% difference between 3D and RG protocols for CT and PET, respectively. Between 10 RG phases in PET, 53.4% of features demonstrated percent differences less than 5%. The features with least variability for PET were sphericity, spherical disproportion, entropy (first and second order, sum entropy, information measure of correlation 2, Short Run Emphasis (SRE, Long Run Emphasis (LRE, and Run Percentage (RPC; and those for CT were minimum intensity, mean intensity, Root Mean Square (RMS, Short Run Emphasis (SRE, and RPC. Quantitative analysis using a 3D acquisition versus RG acquisition (to reduce the effects of motion provided notably different image feature values. This study suggests that the variability between 3D and RG features is mainly due to the impact of respiratory motion.

  18. Diffusion-weighted magnetic resonance imaging to predict response of hepatocellular carcinoma to chemoembolization

    Institute of Scientific and Technical Information of China (English)

    Johnathan; C; Chung; Neel; K; Naik; Robert; J; Lewandowski; Mary; F; Mulcahy; Laura; M; Kulik; Kent; T; Sato; Robert; K; Ryu; Riad; Salem; Andrew; C; Larson; Reed; A; Omary

    2010-01-01

    AIM: To investigate whether intra-procedural diffusion- weighted magnetic resonance imaging can predict response of hepatocellular carcinoma (HCC) during trans- catheter arterial chemoembolization (TACE). METHODS: Sixteen patients (15 male), aged 59 ±11 years (range: 42-81 years) underwent a total of 21 separate treatments for unresectable HCC in a hybrid magnetic resonance/interventional radiology suite. Ana- tomical imaging and diffusion-weighted imaging (b = 0, 500 s/mm2) were performed on a 1.5-T unit. ...

  19. Diagnosis of pericardial cysts using diffusion weighted magnetic resonance imaging: A case series

    OpenAIRE

    Mousavi Negareh; Czarnecki Andrew; Zeglinski Matthew; Du Joe; Sud Maneesh; Walker Jonathon R; Raja Asam; Jassal Davinder S; Kirkpatrick Iain DC

    2011-01-01

    Abstract Introduction Congenital pericardial cysts are benign lesions that arise from the pericardium during embryonic development. The diagnosis is based on typical imaging features, but atypical locations and signal magnetic resonance imaging sequences make it difficult to exclude other lesions. Diffusion-weighted magnetic resonance imaging is a novel method that can be used to differentiate tissues based on their restriction to proton diffusion. Its use in differentiating pericardial cysts...

  20. 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.

  1. Diffusion-weighted imaging in the prostate: an apparent diffusion coefficient comparison of half-Fourier acquisition single-shot turbo spin-echo and echo planar imaging.

    Science.gov (United States)

    Babourina-Brooks, Ben; Cowin, Gary J; Wang, Deming

    2012-02-01

    Prostate cancer detection using diffusion-weighted imaging is highly affected by the accuracy of the apparent diffusion coefficient (ADC) values in an image. Echo planar imaging (EPI) is a fast sequence commonly used for diffusion imaging but has inherent magnetic susceptibility and chemical shift artefacts associated. A diffusion sequence that is less affected by these artefacts is therefore advantageous. The half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence was chosen. The diffusion sequences were compared in image quality, repeatability of the ADC value and the effect on the ADC value with varied b values. Eight volunteers underwent three scans of each sequence, on a 1.5-T Siemens system, using b values of 0, 150, 300, 450, 600, 750, 900 and 1000 s/mm(2). ADC maps were created to address the reproducibility of the ADC value when using two b values compared to eight b values. The ADC value using all b values with the HASTE sequence gave the best performance in all tested categories. Both sequences gave significantly different ADC mean values for two b values compared to when using eight b values (Perror is present when using two b values. HASTE was shown to be an improvement over EPI in terms of repeatability, signal variation within a region of interest and standard deviation over the volunteer set. The improved accuracy of the ADC value in the HASTE sequence makes it potentially a more sensitive tumor detection technique.

  2. Diffusion-weighted MR imaging for differentiating borderline from malignant epithelial tumours of the ovary: pathological correlation

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Shu Hui; Qiang, Jin Wei; Ma, Feng Hua; Cai, Song Qi; Li, Hai Ming [Fudan University, Department of Radiology, Jinshan Hospital, Shanghai (China); Zhang, Guo Fu [Fudan University, Department of Radiology, Obstetrics and Gynecology Hospital, Shanghai (China); Wang, Li [Fudan University, Department of Pathology, Jinshan Hospital, Shanghai (China)

    2014-09-15

    To investigate diffusion-weighted (DW) magnetic resonance (MR) imaging for differentiating borderline from malignant epithelial tumours of the ovary. This retrospective study included 60 borderline epithelial ovarian tumours (BEOTs) in 48 patients and 65 malignant epithelial ovarian tumours (MEOTs) in 54 patients. DW imaging as well as conventional MR imaging was performed. Signal intensity on DW imaging was assessed and apparent diffusion coefficient (ADC) value was measured. The results were correlated with histopathology and cell density. The majority of MEOTs showed high signal intensity on DW imaging, whereas most BEOTs showed low or moderate signal intensity (P = 0.000). The mean ADC value of the solid components in BEOTs (1.562 ± 0.346 x 10{sup -3} mm{sup 2}/s) was significantly higher than in MEOTs (0.841 ± 0.209 x 10{sup -3} mm{sup 2}/s). A threshold value of 1.039 x 10{sup -3} mm{sup 2}/s permitted the distinction with a sensitivity of 97.0 %, a specificity of 92.2 % and an accuracy of 96.4 %. There was an inverse correlation between ADC value and cell density (r = -0.609; P = 0.0000) which was significantly lower in BEOTs than in MEOTs. DW imaging is useful for differentiating borderline from malignant epithelial tumours of the ovary. (orig.)

  3. MR neurography of ulnar nerve entrapment at the cubital tunnel: a diffusion tensor imaging study.

    Science.gov (United States)

    Breitenseher, Julia B; Kranz, Gottfried; Hold, Alina; Berzaczy, Dominik; Nemec, Stefan F; Sycha, Thomas; Weber, Michael; Prayer, Daniela; Kasprian, Gregor

    2015-07-01

    MR neurography, diffusion tensor imaging (DTI) and tractography at 3 Tesla were evaluated for the assessment of patients with ulnar neuropathy at the elbow (UNE). Axial T2-weighted and single-shot DTI sequences (16 gradient encoding directions) were acquired, covering the cubital tunnel of 46 patients with clinically and electrodiagnostically confirmed UNE and 20 healthy controls. Cross-sectional area (CSA) was measured at the retrocondylar sulcus and FA and ADC values on each section along the ulnar nerve. Three-dimensional nerve tractography and T2-weighted neurography results were independently assessed by two raters. Patients showed a significant reduction of ulnar nerve FA values at the retrocondylar sulcus (p = 0.002) and the deep flexor fascia (p = 0.005). At tractography, a complete or partial discontinuity of the ulnar nerve was found in 26/40 (65%) of patients. Assessment of T2 neurography was most sensitive in detecting UNE (sensitivity, 91%; specificity, 79%), followed by tractography (88%/69%). CSA and FA measurements were less effective in detecting UNE. T2-weighted neurography remains the most sensitive MR technique in the imaging evaluation of clinically manifest UNE. DTI-based neurography at 3 Tesla supports the MR imaging assessment of UNE patients by adding quantitative and 3D imaging data. • DTI and tractography support conventional MR neurography in the detection of UNE • Regionally reduced FA values and discontinuous tractography patterns indicate UNE • T2-weighted MR neurography remains the imaging gold standard in cases of UNE • DTI-based ulnar nerve tractography offers additional topographic information in 3D.

  4. Quantification of diffusion-weighted images (DWI) and apparent diffusion coefficient maps (ADC) in the detection of acute stroke

    Science.gov (United States)

    Tulipano, P. Karina; Millar, William S.; Imielinska, Celina; Liu, Xin; Rosiene, Joel; D'Ambrosio, Anthony L.

    2006-03-01

    Magnetic resonance (MR) imaging is an imaging modality that is used in the management and diagnosis of acute stroke. Common MR imaging techniques such as diffusion weighted imaging (DWI) and apparent diffusion coefficient maps (ADC) are used routinely in the diagnosis of acute infarcts. However, advances in radiology information systems and imaging protocols have led to an overload of image information that can be difficult to manage and time consuming. Automated techniques to assist in the identification of acute ischemic stroke can prove beneficial to 1) the physician by providing a mechanism for early detection and 2) the patient by providing effective stroke therapy at an early stage. We have processed DW images and ADC maps using a novel automated Relative Difference Map (RDM) method that was tailored to the identification and delineation of the stroke region. Results indicate that the technique can delineate regions of acute infarctions on DW images and ADC maps. A formal evaluation of the RDM algorithm was performed by comparing accuracy measurements between 1) expert generated ground truths with the RDM delineated DWI infarcts and 2) RDM delineated DWI infarcts with RDM delineated ADC infarcts. The accuracy measurements indicate that the RDM delineated DWI infarcts are comparable to the expert generated ground truths. The true positive volume fraction value (TPVF), between RDM delineated DWI and ADC infarcts, is nonzero for all cases with an acute infarct while the value for non-acute cases remains zero.

  5. Imaging artifacts induced by electrical stimulation during conventional fMRI of the brain.

    Science.gov (United States)

    Antal, Andrea; Bikson, Marom; Datta, Abhishek; Lafon, Belen; Dechent, Peter; Parra, Lucas C; Paulus, Walter

    2014-01-15

    Functional magnetic resonance imaging (fMRI) of brain activation during transcranial electrical stimulation is used to provide insight into the mechanisms of neuromodulation and targeting of particular brain structures. However, the passage of current through the body may interfere with the concurrent detection of blood oxygen level-dependent (BOLD) signal, which is sensitive to local magnetic fields. To test whether these currents can affect concurrent fMRI recordings we performed conventional gradient echo-planar imaging (EPI) during transcranial direct current (tDCS) and alternating current stimulation (tACS) on two post-mortem subjects. tDCS induced signals in both superficial and deep structures. The signal was specific to the electrode montage, with the strongest signal near cerebrospinal fluid (CSF) and scalp. The direction of change relative to non-stimulation reversed with tDCS stimulation polarity. For tACS there was no net effect of the MRI signal. High-resolution individualized modeling of current flow and induced static magnetic fields suggested a strong coincidence of the change EPI signal with regions of large current density and magnetic fields. These initial results indicate that (1) fMRI studies of tDCS must consider this potentially confounding interference from current flow and (2) conventional MRI imaging protocols can be potentially used to measure current flow during transcranial electrical stimulation. The optimization of current measurement and artifact correction techniques, including consideration of the underlying physics, remains to be addressed.

  6. Accuracy of diffusion tensor imaging for diagnosing cervical spondylotic myelopathy in patients showing spinal cord compression

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Bo; Chung Tae Sub; Kim, Sung Jun; Yoo, Yeon Hwa; Yoon, Choon Sik; Park, Jung Hyun [Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); Lee, Young Han [Dept. of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); Jeong, Eun Kee [Dept. of Radiology, Utah Center for Advanced Imaging Research, University of Utah, Salt Lake (United States); Kim, In Seong [Siemens Healthcare, Seoul (Korea, Republic of)

    2015-12-15

    To assess the performance of diffusion tensor imaging (DTI) for the diagnosis of cervical spondylotic myelopathy (CSM) in patients with deformed spinal cord but otherwise unremarkable conventional magnetic resonance imaging (MRI) findings. A total of 33 patients who underwent MRI of the cervical spine including DTI using two-dimensional single-shot interleaved multi-section inner volume diffusion-weighted echo-planar imaging and whose spinal cords were deformed but showed no signal changes on conventional MRI were the subjects of this study. Mean diffusivity (MD), longitudinal diffusivity (LD), radial diffusivity (RD), and fractional anisotropy (FA) were measured at the most stenotic level. The calculated performance of MD, FA, MD∩FA (considered positive when both the MD and FA results were positive), LD∩FA (considered positive when both the LD and FA results were positive), and RD∩FA (considered positive when both the RD and FA results were positive) in diagnosing CSM were compared with each other based on the estimated cut-off values of MD, LD, RD, and FA from receiver operating characteristic curve analysis with the clinical diagnosis of CSM from medical records as the reference standard. The MD, LD, and RD cut-off values were 1.079 × 10'-{sup 3}, 1.719 × 10{sup -3}, and 0.749 × 10{sup -3} mm{sup 2}/sec, respectively, and that of FA was 0.475. Sensitivity, specificity, positive predictive value and negative predictive value were: 100 (4/4), 44.8 (13/29), 20 (4/20), and 100 (13/13) for MD; 100 (4/4), 27.6 (8/29), 16 (4/25), and 100 (8/8) for FA; 100 (4/4), 58.6 (17/29), 25 (4/16), and 100 (17/17) for MD∩FA; 100 (4/4), 68.9 (20/29), 30.8 (4/13), and 100 (20/20) for LD∩FA; and 75 (3/4), 68.9 (20/29), 25 (3/12), and 95.2 (20/21) for RD∩FA in percentage value. Diagnostic performance comparisons revealed significant differences only in specificity between FA and MD∩FA (p = 0.003), FA and LD∩FA (p < 0.001), FA and RD∩FA (p < 0.001), MD and LD

  7. Rigorous mathematical investigation of a nonlinear anisotropic diffusion-based image restoration model

    Directory of Open Access Journals (Sweden)

    Tudor Barbu

    2014-06-01

    Full Text Available A nonlinear diffusion based image denoising technique is introduced in this paper. The proposed PDE denoising and restoration scheme is based on a novel diffusivity function that uses an automatically detected conductance parameter. A robust mathematical treatment is also provided for our anisotropic diffusion model. We demonstrate that edge-stopping function model is properly chosen, explaining the mathematical reasons behind it. Also, we perform a rigorous mathematical investigation on of the existence and uniqueness of the solution of our nonlinear diffusion equation. This PDE-based noise removal approach outperforms most diffusion-based methods, producing considerably better smoothing results and providing a much better edge preservation.

  8. Development and organization of the human brain tissue compartments across the lifespan using diffusion tensor imaging.

    Science.gov (United States)

    Hasan, Khader M; Sankar, Ambika; Halphen, Christopher; Kramer, Larry A; Brandt, Michael E; Juranek, Jenifer; Cirino, Paul T; Fletcher, Jack M; Papanicolaou, Andrew C; Ewing-Cobbs, Linda

    2007-10-29

    We used a diffusion tensor imaging-based whole-brain tissue segmentation to characterize age-related changes in (a) whole-brain grey matter, white matter, and cerebrospinal fluid relative to intracranial volume and (b) the corresponding brain tissue microstructure using measures of diffusion tensor anisotropy and mean diffusivity. The sample, a healthy cohort of 119 right-handed males and females aged 7-68 years. Our results demonstrate that white matter and grey matter volumes and their corresponding diffusion tensor anisotropy and mean diffusivity follow nonlinear trajectories with advancing age. In contrast, cerebrospinal fluid volume increases linearly with age.

  9. MR imaging of hypoglycemic encephalopathy: lesion distribution and prognosis prediction by diffusion-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jeong-Hyun; Kim, Young-Joo; Yoo, Won-Jong; Ihn, Yon-Kwon; Kim, Jee-Young; Kim, Bum-Soo [The Catholic University of Korea, Department of Radiology, College of Medicine, Uijongbu, Kyunggi-do (Korea); Song, Ha-Hun [Cheju Halla General Hospital, Department of Radiology, Jeju (Korea)

    2009-10-15

    The aim of this study was to evaluate the patterns of hypoglycemic encephalopathy on diffusion-weighted imaging (DWI) and the relationship between the imaging patterns and clinical outcomes. This retrospective study included 17 consecutive patients that had hypoglycemic encephalopathy with DWI abnormalities. The topographic distributions of the DWI abnormalities of the cortex, deep gray matter, and white matter structures were assessed. In addition, possible correlation between the patterns of brain injury on DWI and clinical outcomes was investigated. There were three patterns of DWI abnormalities: involvement of both gray and white matter (n=8), selective involvement of gray matter (n=4), and selective involvement of white matter (n=5). There was no significant difference in the initial blood glucose levels among patients for each of the imaging patterns. Most patients (16/17) had bilateral symmetrical abnormalities. Among patients with bilateral symmetrical gray and/or white matter injuries, one had moderate to severe disability and 14 remained in a persistent vegetative state. The two patients with a focal unilateral white matter abnormality and a localized splenial abnormality recovered without neurological deficits. The results of this study showed that white matter was more sensitive to hypoglycemia than previously thought and there was no specific association between the patterns of injury and clinical outcomes whether the cerebral cortex, deep gray matter, and/or white matter were affected. Diffuse and extensive injury observed on the DWI predicts a poor neurologic outcome in patients with hypoglycemic injuries. (orig.)

  10. An improved permutation-diffusion type image cipher with a chaotic orbit perturbing mechanism.

    Science.gov (United States)

    Chen, Jun-xin; Zhu, Zhi-liang; Fu, Chong; Yu, Hai

    2013-11-18

    During the past decades, chaos-based permutation-diffusion type image cipher has been widely investigated to meet the increasing demand for real-time secure image transmission over public networks. However, the existing researches almost exclusively focus on the improvements of the permutation and diffusion methods independently, without consideration of cooperation between the two processes. In this paper, an improved permutation-diffusion type image cipher with a chaotic orbit perturbing mechanism is proposed. In the permutation stage, pixels in the plain image are shuffled with a pixel-swapping mechanism, and the pseudorandom locations are generated by chaotic logistic map iteration. Furthermore, a plain pixel related chaotic orbit perturbing mechanism is introduced. As a result, a tiny change in plain image will be spread out during the confusion process, and hence an effective diffusion effect is introduced. By using a reverse direction diffusion method, the introduced diffusion effect will be further diffused to the whole cipher image within one overall encryption round. Simulation results and extensive cryptanalysis justify that the proposed scheme has a satisfactory security with a low computational complexity, which renders it a good candidate for real-time secure image storage and distribution applications.

  11. Preoperative conventional magnetic resonance images versus magnetic resonance arthrography of subacromial impingement syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sang Hyuk; Park, Jung Hwan; Moon, Tae Yong [Pusan National Univ. Yangsan Hospital, Yangsan (Korea, Republic of); Lee, In Sook; Lee, Seung Jun [Pusan National Univ. Hospital, Busan (Korea, Republic of)

    2012-09-15

    To evaluate the usefulness of conventional magnetic resonance images (MRI) for arthroscopic surgery in subacromial impingement syndrome of the shoulder, as an alternative to MR arthrography with additional T2 fat saturation images (MRA). The preoperative MRI of 77 patients (45 females, 32 males) (52 right, 25 left) and MRA of 34 patients (14 females, 20 males) (24 right, 10 left) with subsequent arthroscopic confirmation of subacromial impingement syndrome were reviewed retrospectively. The lesions requiring arthroscopic surgery were 95 subacromial spurs, 101 subacromial bursitis, and 51 full-thickness and 44 partial thickness tears of the supraspinatus among 111 cases for both studies. A two by two table was constructed in order to calculate the sensitivity and specificity of both studies against arthroscopic outcomes. Also we analyzed the false positive and false negative cases of the full-thickness tears individually. The detection rates of subacromial spur and bursitis and full and partial thickness tears of the supraspinatus were 91%, 94%, 77%, and 65% in MRI and 93%, 100%, 83%, and 77% in MRA respectively. Their specificities were 33%, 33%, 90%, and 76% in MRI and 50%, 75%, 100%, and 71% in MRA respectively. Eleven false negative cases in regards to MRI resulted in Ellman's grade 3 partial thickness tear (72.7%), mild bursitis (63.6%), greater tuberosity erosion (45.5%), and negative fluid signal of the glenohumeral joint (81.8%). Three false positive cases on the MRI were induced from errors with lower window depth and width on the imagings. Two false negative cases on MRA were induced from the adhesion between Ellman's grade 3 rim rent tear and the glenohumeral joint cavity. Conventional MR images could be used to decide the arthroscopic surgery in subacromial impingement syndrome, as an alternative to MR arthrography with additional T2 fat saturation images.

  12. Estimating total cerebral microinfarct burden from diffusion-weighted imaging

    Science.gov (United States)

    Auriel, Eitan; Westover, M. Brandon; Bianchi, Matt T; Reijmer, Yael; Martinez-Ramirez, Sergi; Ni, Jun; Van Etten, Ellis; Frosch, Matthew P; Fotiadis, Panagiotis; Schwab, Kris; Vashkevich, Anastasia; Boulouis, Grégoire; Younger, Alayna P; Johnson, Keith A; Sperling, Reisa A; Hedden, Trey; Gurol, M. Edip; Viswanathan, Anand; Greenberg, Steven M

    2015-01-01

    Background and Purpose Cerebral microinfarcts (CMI) are important contributors to vascular cognitive impairment. MRI diffusion-weighted imaging (DWI) hyperintensities have been suggested to represent acute CMI. We aim to describe a mathematical method for estimating total number of CMI based on the presence of incidental DWI lesions. Methods We reviewed MRI scans of subjects with cognitive decline, cognitively normal subjects and previously reported subjects with past intracerebral hemorrhage (ICH). Based on temporal and spatial characteristics of DWI lesions we estimated the annual rate of CMI needed to explain the observed rate of DWI lesion detection in each group. To confirm our estimates we performed extensive sampling for CMI in the brain of a deceased subject with past lobar ICH who found to have a DWI lesion during life. Results Clinically silent DWI lesions were present in 13 of 343 (3.8%) cognitively impaired, and 10 of 199 (5%) cognitively intact normal non-ICH patients, both lower than the incidence in the past ICH patients (23 of 178, 12.9%, p<0.0006). The predicted annual incidence of CMI ranges from 16 to 1566 for non-ICH and 50 to 5041 for ICH individuals. Histologic sampling revealed a total of 60 lesions in 32 sections. Based on previously reported methods, this density of CMI yields an estimated total brain burden MLE of 9321 CMIs (95% CI 7255–11990). Conclusions Detecting even a single DWI lesion suggests an annual incidence of hundreds of new CMI. The cumulative effects of these lesions may directly contribute to small-vessel-related vascular cognitive impairment PMID:26159796

  13. A Novel Imaging Marker for Small Vessel Disease Based on Skeletonization of White Matter Tracts and Diffusion Histograms.

    Science.gov (United States)

    Baykara, Ebru; Gesierich, Benno; Adam, Ruth; Tuladhar, Anil Man; Biesbroek, J Matthijs; Koek, Huiberdina L; Ropele, Stefan; Jouvent, Eric; Chabriat, Hugues; Ertl-Wagner, Birgit; Ewers, Michael; Schmidt, Reinhold; de Leeuw, Frank-Erik; Biessels, Geert Jan; Dichgans, Martin; Duering, Marco

    2016-10-01

    To establish a fully automated, robust imaging marker for cerebral small vessel disease (SVD) and related cognitive impairment that is easy to implement, reflects disease burden, and is strongly associated with processing speed, the predominantly affected cognitive domain in SVD. We developed a novel magnetic resonance imaging marker based on diffusion tensor imaging, skeletonization of white matter tracts, and histogram analysis. The marker (peak width of skeletonized mean diffusivity [PSMD]) was assessed along with conventional SVD imaging markers. We first evaluated associations with processing speed in patients with genetically defined SVD (n = 113). Next, we validated our findings in independent samples of inherited SVD (n = 57), sporadic SVD (n = 444), and memory clinic patients with SVD (n = 105). The new marker was further applied to healthy controls (n = 241) and to patients with Alzheimer's disease (n = 153). We further conducted a longitudinal analysis and interscanner reproducibility study. PSMD was associated with processing speed in all study samples with SVD (p-values between 2.8 × 10(-3) and 1.8 × 10(-10) ). PSMD explained most of the variance in processing speed (R(2) ranging from 8.8% to 46%) and consistently outperformed conventional imaging markers (white matter hyperintensity volume, lacune volume, and brain volume) in multiple regression analyses. Increases in PSMD were linked to vascular but not to neurodegenerative disease. In longitudinal analysis, PSMD captured SVD progression better than other imaging markers. PSMD is a new, fully automated, and robust imaging marker for SVD. PSMD can easily be applied to large samples and may be of great utility for both research studies and clinical use. Ann Neurol 2016;80:581-592. © 2016 American Neurological Association.

  14. Diagnosis of acute cerebral infarction using diffusion-weighted imaging by low field (0.2 T) magnetic resonance image

    Energy Technology Data Exchange (ETDEWEB)

    Okuyama, Tohru; Sasamori, Yumiko; Takahashi, Hachisaburou; Mikami, Juniti; Ishii, Yuuko; Okada, Kinya; Shirafuji, Naoko; Kashiwakura, Takeshi [Takahashi Neurosurgical Hospital, Sapporo (Japan)

    2000-09-01

    The purpose of this study is to confirm the diagnosis of acute cerebral infarction on diffusion-weighted imaging using low field (0.2 T) magnetic resonance image (MRI). Acute cerebral infarctions in 51 patients were examined on diffusion-weighted imaging using low field MRI within 48 hours after clinical symptoms. Diffusion-weighted imaging was examined using line scan method. Twenty-four cases were cortical infarction, and twenty-two cases were perforating infarction. In five cases out of 51 cases, ischemic regions were not detected as abnormal high signal intensity area on diffusion-weighted imaging. Four cases of no abnormal detection were transient ischemic attack, and the other one was a perforating infarction. The earliest detection time in cortical infarction cases was 1 hour and 20 minutes. On the other hand, the earliest detection time in perforating infarction cases was 3 hours. Detective ability for acute cerebral infarction on diffusion-weighted imaging by low field MRI was depending on both size and lesion of infarction. That is to say, either small size or brain stem infarction was hard to detect. Thin slice and vertical slice examination for the infarction may improve to diagnose in low field MRI. Our conclusion is acute cerebral infarction was able to be diagnosed on diffusion-weighted imaging by low field as well as high field MRI. (author)

  15. Insight to Nanoparticle Size Analysis—Novel and Convenient Image Analysis Method Versus Conventional Techniques

    Science.gov (United States)

    Vippola, Minnamari; Valkonen, Masi; Sarlin, Essi; Honkanen, Mari; Huttunen, Heikki

    2016-03-01

    The aim of this paper is to introduce a new image analysis program "Nanoannotator" particularly developed for analyzing individual nanoparticles in transmission electron microscopy images. This paper describes the usefulness and efficiency of the program when analyzing nanoparticles, and at the same time, we compare it to more conventional nanoparticle analysis techniques. The techniques which we are concentrating here are transmission electron microscopy (TEM) linked with different image analysis methods and X-ray diffraction techniques. The developed program appeared as a good supplement to the field of particle analysis techniques, since the traditional image analysis programs suffer from the inability to separate the individual particles from agglomerates in the TEM images. The program is more efficient, and it offers more detailed morphological information of the particles than the manual technique. However, particle shapes that are very different from spherical proved to be problematic also for the novel program. When compared to X-ray techniques, the main advantage of the small-angle X-ray scattering (SAXS) method is the average data it provides from a very large amount of particles. However, the SAXS method does not provide any data about the shape or appearance of the sample.

  16. Insight to Nanoparticle Size Analysis-Novel and Convenient Image Analysis Method Versus Conventional Techniques.

    Science.gov (United States)

    Vippola, Minnamari; Valkonen, Masi; Sarlin, Essi; Honkanen, Mari; Huttunen, Heikki

    2016-12-01

    The aim of this paper is to introduce a new image analysis program "Nanoannotator" particularly developed for analyzing individual nanoparticles in transmission electron microscopy images. This paper describes the usefulness and efficiency of the program when analyzing nanoparticles, and at the same time, we compare it to more conventional nanoparticle analysis techniques. The techniques which we are concentrating here are transmission electron microscopy (TEM) linked with different image analysis methods and X-ray diffraction techniques. The developed program appeared as a good supplement to the field of particle analysis techniques, since the traditional image analysis programs suffer from the inability to separate the individual particles from agglomerates in the TEM images. The program is more efficient, and it offers more detailed morphological information of the particles than the manual technique. However, particle shapes that are very different from spherical proved to be problematic also for the novel program. When compared to X-ray techniques, the main advantage of the small-angle X-ray scattering (SAXS) method is the average data it provides from a very large amount of particles. However, the SAXS method does not provide any data about the shape or appearance of the sample.

  17. Restoration of digital images with known space-variant blurs from conventional optical systems

    Science.gov (United States)

    Costello, Thomas P.; Mikhael, Wasfy B.

    1999-07-01

    Space-variant (SV) digital image restoration methods attempt to restore images degraded by blurs that vary over the image field. One specific source of SV blurs is that of geometrical optical aberrations, which divert light rays as they pass through the optical system away from an ideal focal point. For simple optical system, aberrations can become significant even at moderate field angles. Restoration methods have been developed for some space- variant aberrations when they are individually dominant, but such dominance is not typically characteristic of conventional optical systems. In this paper, an iterative method of restoration that is applicable to generalized, known space-variant blurs is applied to simulations of images generated with a spherical lines. The method is based on the Gauss-Seidel method of solution to systems of linear equations. The method is applied to sub-images having off- axis displacements of up to 453 pixels, and found to be superior in restoration effectiveness to Fourier methods in that range of field angles.

  18. Diffusion tensor Imaging and chemical shift imaging assessment of heterogeneity in low grade glioma under temozolomide chemotherapy

    NARCIS (Netherlands)

    Sijens, P. E.; Heesters, Martinus; Enting, Roeline; van der Graaf, W. T. A.; Potze, J. H.; Irwan, Roy; Meiners, L. C.; Oudkerk, M.

    2007-01-01

    Diffusion tensor imaging and multiple voxel magnetic resonance spectroscopy were performed in the MRI follow-up of a patient with a glioma treated with temozolomide chemotherapy. Tumor shrinkage was paralleled by reductions in choline level and by increases in apparent diffusion coefficient indicati

  19. Using anisotropic diffusion equations in pixon domain for image de-noising

    DEFF Research Database (Denmark)

    Nadernejad, Ehsan; Forchhammer, Søren; Sharifzadeh, Sara

    2013-01-01

    Image enhancement is an essential phase in many image processing algorithms. In any image de-noising algorithm, it is a major concern to keep the interesting structures of the image. Such interesting structures in an image often correspond to the discontinuities in the image (edges). In this paper......, we propose a new algorithm for image de-noising using anisotropic diffusion equations in pixon domain. In this approach, diffusion equations are applied on the pixonal model of the image. The algorithm has been examined on a variety of standard images and the performance has been compared...... with algorithms known from the literature. The experimental results show that in comparison with the other existing methods, the proposed algorithm has a better performance in de-noising and preserving image edges....

  20. The effects of molecular diffusion in spatially encoded magnetic resonance imaging

    Science.gov (United States)

    Marhabaie, Sina; Bodenhausen, Geoffrey; Pelupessy, Philippe

    2016-12-01

    In spatially encoded MRI, the signal is acquired sequentially for different coordinates. In particular for single-scan acquisitions in inhomogeneous fields, spatially encoded methods improve the image quality compared to traditional k-space encoding. Previously, much attention has been paid in order to homogenize T2 losses across the sample. In this work, we investigate the effects of diffusion on the image quality in spatially encoded MRI. We show that losses due to diffusion are often not uniform along the spatially encoded dimension, and how to adapt spatially encoded sequences in order to obtain uniformly diffusion-weighted images.

  1. The Application of Diffusion- and Perfusion-Weighted Magnetic Resonance Imaging in the Diagnosis and Therapy of Acute Cerebral Infarction

    Directory of Open Access Journals (Sweden)

    Ying Han

    2006-01-01

    Full Text Available Diffusion- and perfusion-weighted magnetic resonance imaging (DWI and PWI was applied for stroke diagnose in 120 acute (<48 h ischemic stroke patients. At hyperacute (<6 h stage, it is difficult to find out the infarction zone in conventional T1 or T2 image, but it is easy in DWI, apparent diffusion coefficient (ADC map; when at 3–6-hour stage it is also easy in PWI, cerebral blood flow (CBF map, cerebral blood volume (CBV map, and mean transit time (MTT map; at acute (6–48 h stage, DWI or PWI is more sensitive than conventional T1 or T2 image too. Combining DWI with ADC, acute and chronic infarction can be distinguished. Besides, penumbra which should be developed in meaning was used as an indication or to evaluate the therapeutic efficacy. There were two cases (<1.5 h that broke the model of penumbra because abnormity was found in DWI but not that in PWI, finally they recovered without any sequela.

  2. Reduction of blooming artifacts in cardiac CT images by blind deconvolution and anisotropic diffusion filtering

    Science.gov (United States)

    Castillo-Amor, Angélica M.; Navarro-Navia, Cristian A.; Cadena-Bonfanti, Alberto J.; Contreras-Ortiz, Sonia H.

    2015-12-01

    Even though CT is an imaging technique that offers high quality images, limitations on its spatial resolution cause blurring in small objects with high contrast. This phenomenon is known as blooming artifact and affects cardiac images with small calcifications and stents. This paper describes an approach to reduce the blooming artifact and improve resolution in cardiac images using blind deconvolution and anisotropic diffusion filtering. Deconvolution increases resolution but reduces signal-to-noise ratio, and the anisotropic diffusion filter counteracts this effect without affecting the edges in the image.

  3. Diffusion weighted magnetic resonance imaging: ischemic and traumatic injury of the central nervous system; Diffusionsgewichtete MRI: ischaemische und traumatische Verletzungen des Zentralnervensystems

    Energy Technology Data Exchange (ETDEWEB)

    Huisman, T.A.G.M.; Sorensen, A.G. [Massachusetts General Hospital and Harvard Medical School, Boston (United States). MGH-NMR Center; Hawighorst, H.; Benoit, C.H. [Swiss Paraplegic Center Nottwil (Switzerland). Inst. of Radiology

    2001-12-01

    Diffusion weighted magnetic resonance imaging (DWI) represents a recent development that extends imaging from the depiction of the neuroanatomy into the field of functional and physiologic processes. DWI measures a fundamentally different physiologic parameter than conventional MRI. Image contrast is related to differences in the microscopic motion (diffusion) of water molecules within brain tissue rather than a change in total tissue water. Consequently, DWI can reveal pathology where conventional T1- and T2-weighted MR images are negative. DWI has clinically proven its value in the assessment of acute cerebral stroke and trauma by showing cerebral injury early due to its ability to discriminate between lesions with cytotoxic edema (decreased diffusion) from lesions with vasogenic edema (increased diffusion). Full tensor DWI allows to calculate a variety of functional maps, the most widely used maps include maps of apparent diffusion coefficients and isotropic diffusion. In addition maps of anisotropic diffusion can be calculated which are believed to give information about the integrity and location of fiber tracts. This functional-anatomical information will most probably play an increasingly important role in the early detection of primary and secondary tissue injury from various reasons and could guide and validate current and future neuroprotective treatments. (orig.) [German] Die diffusionsgewichtete Magnetresonanz Tomografie (DWI) stellt ein neues Verfahren dar, welches die Bildgebung von der einfachen Darstellung der Neuroanatomie um das Feld der funktionalen und physiologischen Prozesse erweitert. Im Gegensatz zur konventionellen MRT misst die DWI einen vollkommen anderen physiologischen Parameter. Der Bildkontrast haengt von Unterschieden in der Mikrobewegung (Diffusion) der Wassermolekuele im Hirngewebe ab. Daher kann die DWI pathologische Prozesse aufzeichnen, wo konventionelle T1- und T2-gewichtete MR Bilder unauffaellig bleiben. In der klinischen

  4. Functional evaluation of hydronephrosis by diffusion-weighted MR imaging: Relationship between apparent diffusion coefficient and split glomerular filtration rate

    Energy Technology Data Exchange (ETDEWEB)

    Toyoshima, S.; Noguchi, K.; Seto, H.; Shimizu, M.; Watanabe, N. [Toyama Medical and Pharmaceutical Univ. (Japan). Dept. of Radiology

    2000-11-01

    To determine the relationship between apparent diffusion coefficient (ADC) values measured by diffusion-weighted MR imaging and split renal function determined by renal scintigraphy in patients with hydronephrosis. Material and Methods: Diffusion-weighted imaging on a 1.5 T MR unit and renal scintigraphy were performed in 36 patients with hydronephrosis (45 hydronephrotic kidneys, 21 non-hydronephrotic kidneys). ADC values of the individual kidneys were measured by diffusion-weighted MR imaging. Split renal function (glomerular filtration rate (GFR)) was determined by renal scintigraphy using {sup 99m}Tc-DTPA. The relationship between ADC values and split GFR was examined in 66 kidneys. The hydronephrotic kidneys were further classified into three groups (severe renal dysfunction, GFR <10 ml/min, n=7; moderate renal dysfunction, GFR 10-25 ml/min, n=10; normal renal function, GFR >25 ml/min, n=28), and mean values for ADCs were calculated. Results: In hydronephrotic kidneys, there was a moderate positive correlation between ADC values and split GFR (R2=0.56). On the other hand, in non-hydronephrotic kidneys, poor correlation between ADC values and split GFR was observed (R2=0.08). The mean values for ADCs of the dysfunctioning hydronephrotic kidneys (severe renal dysfunction, 1.32x10{sup -3}{+-}0.18x10{sup -3} mm{sup 2}/s; moderate renal dysfunction, 1.38x10{sup -3}{+-}0.10x10{sup -3} mm2/s) were significantly lower than that of the normal functioning hydronephrotic kidneys (1.63x10{sup -3}{+-}0.12{+-}10{sup -3} mm{sup 2}/s). Conclusion: These results indicated that measurement of ADC values by diffusion-weighted MR imaging has a potential value in the evaluation of the functional status of hydronephrotic kidneys.

  5. Role of diffusion-weighted magnetic resonance imaging in the diagnosis of extrahepatic cholangiocarcinoma

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    AIM: To determine the clinical value of diffusion-weight- ed imaging (DWI) for the diagnosis of extrahepatic cholangiocarcinoma (EHCC) by comparing the diagnostic sensitivity of DWI and magnetic resonance cholan-giopancreatography (MRCP). METHODS: Magnetic resonance imaging examination was performed in 56 patients with suspected EHCC. T1- weighted imaging, T2-weighted imaging, MRCP and DWI sequence, DWI using single-shot spin-echo echoplanar imaging sequence with different b values (100, 300, 500, 800 and 1...

  6. Collagen imaged by Coherent X-ray Diffraction: towards a complementary tool to conventional scanning SAXS

    Energy Technology Data Exchange (ETDEWEB)

    Berenguer de la Cuesta, Felisa; Bean, Richard J; Bozec, Laurent; Robinson, Ian K [London Centre for Nanotechnology (LCN), University College London (UCL), London WC1H 0AH (United Kingdom); McCallion, Catriona; Wallace, Kris [Department of Physics and Astronomy, University College London (UCL), London WC1E 6BT (United Kingdom); Hiller, Jen C; Terrill, Nicholas J, E-mail: f.berenguer@ucl.ac.u [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

    2010-10-01

    Third generation x-ray sources offer unique possibilities for exploiting coherence in the study of materials. New insights in the structure and dynamics of soft condensed matter and biological samples can be obtained by coherent x-ray diffraction (CXD). However, the experimental procedures for applying these methods to collagen tissues are still under development. We present here an investigation for the optimal procedure in order to obtain high quality CXD data from collagen tissues. Sample handling and preparation and adequate coherence defining apertures are among the more relevant factors to take into account. The impact of the results is also discussed, in particular in comparison with the information that can be extracted from conventional scanning small angle x-ray scattering (SAXS). Images of collagen tissues obtained by CXD reconstructions will give additional information about the local structure with higher resolution and will complement scanning SAXS images.

  7. Non-Parametric Tests of Structure for High Angular Resolution Diffusion Imaging in Q-Space

    CERN Document Server

    Olhede, Sofia C

    2010-01-01

    High angular resolution diffusion imaging data is the observed characteristic function for the local diffusion of water molecules in tissue. This data is used to infer structural information in brain imaging. Non-parametric scalar measures are proposed to summarize such data, and to locally characterize spatial features of the diffusion probability density function (PDF), relying on the geometry of the characteristic function. Summary statistics are defined so that their distributions are, to first order, both independent of nuisance parameters and also analytically tractable. The dominant direction of the diffusion at a spatial location (voxel) is determined, and a new set of axes are introduced in Fourier space. Variation quantified in these axes determines the local spatial properties of the diffusion density. Non-parametric hypothesis tests for determining whether the diffusion is unimodal, isotropic or multi-modal are proposed. More subtle characteristics of white-matter microstructure, such as the degre...

  8. PRELIMINARY STUDY OF FEASIBILITY OF WHOLE BODY DIFFUSION WEIGHTED IMAGING IN DIAGNOSIS OF METASTASIS OF TUMOR

    Institute of Scientific and Technical Information of China (English)

    Tian-he Yang; Jian-zhong Lin; Xin Wang; Jian-hua Lu; Zhong Chen

    2008-01-01

    Objective To evaluate the feasibility of whole body diffusion weighted imaging (DWI) in the diagnosis of metastatic tumor.Methods Fifty-six patients (40 males and 16 females, age ranging from 29 to 84 years with a mean age of 57 years) with a variety of primary tumors were investigated by whole body DWI combined with computed tomography (CT) and/or conventional magnetic resonance imaging (MRI) scans. Twelve patients underwent positron emission tomography. The final diagnosis was made on the basis of CT or high resolution CT result for lung lesion and MRI or CT result for skull, abdomen and other parts. All tumors were classified into four groups by their diameter: below 1.0 cm, 1.0-1.9 cm, 2.0-2.9 cm, and above 3.0 cm. The sensitivity and specificity of whole body DWI in the detection of metastatic tumor were analyzed.Results The sensitivities of whole body DWI for screening metastasis oftlie four groups were 38%, 75%, 97%, and 100%, respectively. Whole body DWI showed the highest sensitivity and specificity for detecting metastasis of the skeletal system. It was difficult to find metastatic tumor whose diameter was below 1.0 cm, or lymph nodes located in the pelvis with diameter below 2.0 cm. Conclusions Whole body DWI is a promising method in the diagnosis ofmetastastic tumors. With the perfection of scanning parameter, whole body DWI should be a new effective whole body technique for tumor detection.

  9. Human brain diffusion tensor imaging at submillimeter isotropic resolution on a 3Tesla clinical MRI scanner.

    Science.gov (United States)

    Chang, Hing-Chiu; Sundman, Mark; Petit, Laurent; Guhaniyogi, Shayan; Chu, Mei-Lan; Petty, Christopher; Song, Allen W; Chen, Nan-kuei

    2015-09-01

    The advantages of high-resolution diffusion tensor imaging (DTI) have been demonstrated in a recent post-mortem human brain study (Miller et al., NeuroImage 2011;57(1):167-181), showing that white matter fiber tracts can be much more accurately detected in data at a submillimeter isotropic resolution. To our knowledge, in vivo human brain DTI at a submillimeter isotropic resolution has not been routinely achieved yet because of the difficulty in simultaneously achieving high resolution and high signal-to-noise ratio (SNR) in DTI scans. Here we report a 3D multi-slab interleaved EPI acquisition integrated with multiplexed sensitivity encoded (MUSE) reconstruction, to achieve high-quality, high-SNR and submillimeter isotropic resolution (0.85×0.85×0.85mm(3)) in vivo human brain DTI on a 3Tesla clinical MRI scanner. In agreement with the previously reported post-mortem human brain DTI study, our in vivo data show that the structural connectivity networks of human brains can be mapped more accurately and completely with high-resolution DTI as compared with conventional DTI (e.g., 2×2×2mm(3)).

  10. Diffuse Optical Spectroscopy and Imaging to Detect and Quantify Adipose Tissue Browning

    Science.gov (United States)

    Dinish, U. S; Wong, Chi Lok; Sriram, Sandhya; Ong, Wee Kiat; Balasundaram, Ghayathri; Sugii, Shigeki; Olivo, Malini

    2017-01-01

    Adipose (fat) tissue is a complex metabolic organ that is highly active and essential. In contrast to white adipose tissue (WAT), brown adipose tissue (BAT) is deemed metabolically beneficial because of its ability to burn calories through heat production. The conversion of WAT-resident adipocytes to “beige” or “brown-like” adipocytes has recently attracted attention. However, it typically takes a few days to analyze and confirm this browning of WAT through conventional molecular, biochemical, or histological methods. Moreover, accurate quantification of the overall browning process is not possible by any of these methods. In this context, we report the novel application of diffuse reflectance spectroscopy (DRS) and multispectral imaging (MSI) to detect and quantify the browning process in mice. We successfully demonstrated the time-dependent increase in browning of WAT, following its induction through β-adrenergic agonist injections. The results from these optical techniques were confirmed with those of standard molecular and biochemical assays, which measure gene and protein expression levels of UCP1 and PGC-1α, as well as with histological examinations. We envision that the reported optical methods can be developed into a fast, real time, cost effective and easy to implement imaging approach for quantification of the browning process in adipose tissue. PMID:28145475

  11. Conventional and Nuclear Medicine Imaging in Ectopic Cushing's Syndrome: A Systematic Review

    Science.gov (United States)

    Isidori, Andrea M.; Sbardella, Emilia; Zatelli, Maria Chiara; Boschetti, Mara; Vitale, Giovanni; Colao, Annamaria

    2015-01-01

    Context: Ectopic Cushing's Syndrome (ECS) can be a diagnostic challenge with the hormonal source difficult to find. This study analyzes the accuracy of imaging studies in ECS localization. Evidence Acquisition: Systematic review of medical literature for ECS case series providing individual patient data on at least one conventional imaging technique (computed tomography [CT]/magnetic resonance imaging) and one of the following: 111In-pentetreotide (OCT), 131I/123I-metaiodobenzylguanidine, 18F-fluoro-2-deoxyglucose-positron emission tomography (FDG-PET), 18F-fluorodopa-PET (F-DOPA-PET), 68Ga-DOTATATE-PET/CT or 68Ga-DOTATOC-PET/CT scan (68Gallium-SSTR-PET/CT). Evidence Summary: The analysis comprised 231 patients (females, 50.2%; age, 42.6 ± 17 y). Overall, 52.4% (121/231) had “overt” ECS, 18.6% had “occult” ECS, and 29% had “covert” ECS. Tumors were located in the lung (55.3%), mediastinum-thymus (7.9%), pancreas (8.5%), adrenal glands (6.4%), gastrointestinal tract (5.4%), thyroid (3.7%), and other sites (12.8%), and primary tumors were mostly bronchial neuroendocrine tumors (NETs) (54.8%), pancreatic NETs (8%), mediastinum-thymus NETs (6.9%), gastrointestinal NETs (5.3%), pheochromocytoma (6.4%), neuroblastoma (3.2%), and medullary thyroid carcinoma (3.2%). Tumors were localized by CT in 66.2% (137/207), magnetic resonance imaging in 51.5% (53/103), OCT in 48.9% (84/172), FDG-PET in 51.7% (46/89), F-DOPA-PET in 57.1% (12/21), 131/123I-metaiodobenzylguanidine in 30.8% (4/13), and 68Gallium-SSTR-PET/CT in 81.8% (18/22) of cases. Molecular imaging discovered 79.1% (53/67) of tumors unidentified by conventional radiology, with OCT the most commonly used, revealing the tumor in 64%, followed by FDG-PET in 59.4%. F-DOPA-PET was used in only seven covert cases (sensitivity, 85.7%). Notably, 68Gallium-SSTR-PET/CT had 100% sensitivity among covert cases. Conclusions: Nuclear medicine improves the sensitivity of conventional radiology when tumor site

  12. Conventional versus storage phosphor-plate digital images to visualize the root canal system contrasted with a radiopaque medium.

    Science.gov (United States)

    Naoum, Hani J; Chandler, Nicholas P; Love, Robert M

    2003-05-01

    The pulp tissue was removed from 20 mandibular first molar teeth using 2.5% NaOCl irrigation and hand files. The dried canals were infused with radiopaque contrast medium. Standardized conventional and Digora digital images were obtained of each tooth positioned in a dried mandible at 0- and 30-degree horizontal angulations. Three evaluators rated the image clarity of the 0- and 30-degree original, enhanced, three-dimensional, zoom, and reverse digital image modes as superior, equal, or inferior to corresponding 0- and 30-degree conventional radiographs. The ratings were compared using the Wilcoxon signed rank test. The original, three-dimensional, zoom, or reverse digital images were inferior to the conventional radiographs for clarity of canal anatomy. The enhanced digital images were not always inferior to the conventional radiographs and were the only images superior to the original digital images. Overall, evaluators rated the image clarity of root canal anatomy on conventional radiographs better than on Digora images. However, factors in the experimental design may have contributed to this result.

  13. Microstructural changes of the corticospinal tract in idiopathic normal pressure hydrocephalus: a comparison of diffusion tensor and diffusional kurtosis imaging

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Atsushi; Hori, Masaaki; Aoki, Shigeki [Juntendo University, Department of Radiology, School of Medicine, Bunkyo-ku, Tokyo (Japan); Fukunaga, Issei [Juntendo University, Department of Radiology, School of Medicine, Bunkyo-ku, Tokyo (Japan); Tokyo Metropolitan University, Department of Health Science, Graduate School of Human Health Sciences, Arakawa, Tokyo (Japan); Masutani, Yoshitaka [The University of Tokyo, Division of Radiology and Biomedical Engineering, Graduate School of Medicine, Bunkyo-ku, Tokyo (Japan); Takaaki, Hattori [Tokyo Medical and Dental University, Department of Neurology and Neurological Science, Graduate School, Bunkyo-ku, Tokyo (Japan); Miyajima, Masakazu [Juntendo University, Department of Neurosurgery, School of Medicine, Bunkyo-ku, Tokyo (Japan)

    2013-08-15

    The goals of this study were to examine the usefulness of diffusional kurtosis imaging (DKI) for assessing microstructural changes in the compressed corticospinal tract (CST) among patients with idiopathic normal pressure hydrocephalus (iNPH). Eleven patients with iNPH (mean age: 73.6 years, range: 65-84), who underwent 3-T magnetic resonance imaging, including DKI before surgery, were recruited. Six age-matched, healthy subjects (mean age: 69.8 years, range: 60-75) served as the control group. DKI and diffusion tensor imaging parameters were calculated and compared between the iNPH and the control groups using tract-specific analysis of the CST at the level of the lateral ventricle. Mean diffusional kurtosis (DK) and axial diffusion kurtosis were significantly lower in iNPH patients. However, apparent diffusion coefficient, fractional anisotropy, and axial eigenvalue ({lambda} {sub 1}) were significantly higher in the iNPH group than in the control group. The mechanical pressure caused by ventricular enlargement in iNPH patients might induce formation of well-aligned fiber tracts and increased fiber density in the CST, resulting in decreased DK. DKI is able to depict both the altered microstructure and water molecule movement within neural axons and intra- or extracellular space. In addition, the investigated DKI parameters provide different information about white matter relative to conventional diffusional metrics for iNPH. (orig.)

  14. Prenatal MR diffusion-weighted imaging in a fetus with hemimegalencephaly

    Energy Technology Data Exchange (ETDEWEB)

    Agid, Ronit; Lieberman, Sivan; Gomori, John M. [Hadassah University Hospital, Division of Neuroradiology, Department of Radiology, Kiryat Hadassah, Ein-Karem, P.O. Box 12000, Jerusalem (Israel); Nadjari, Michael [Hadassah University Hospital, Department of Obstetrics and Gynecology, Jerusalem (Israel)

    2006-02-01

    We report a case of hemimegalencephaly diagnosed by prenatal MRI with an emphasis on its appearance on diffusion-weighted images. This case shows that in this condition the enlarged hemisphere may show restricted diffusion on prenatal MRI. In our opinion, this finding may result from a combination of increased cellularity and advanced myelination in the affected hemisphere. Restricted diffusion is an additional valuable indicator in the analysis of the fetal brain. (orig.)

  15. Region-based adaptive anisotropic diffusion for image enhancement and denoising

    Science.gov (United States)

    Wang, Yi; Niu, Ruiqing; Zhang, Liangpei; Shen, Huanfeng

    2010-11-01

    A novel region-based adaptive anisotropic diffusion (RAAD) is presented for image enhancement and denoising. The main idea of this algorithm is to perform the region-based adaptive segmentation. To this end, we use the eigenvalue difference of the structure tensor of each pixel to classify an image into homogeneous detail, and edge regions. According to the different types of regions, a variable weight is incorporated into the anisotropic diffusion partial differential equation for compromising the forward and backward diffusion, so that our algorithm can adaptively encourage strong smoothing in homogeneous regions and suitable sharpening in detail and edge regions. Furthermore, we present an adaptive gradient threshold selection strategy. We suggest that the optimal gradient threshold should be estimated as the mean of local intensity differences on the homogeneous regions. In addition, we modify the anisotropic diffusion discrete scheme by taking into account edge orientations. We believe our algorithm to be a novel mechanism for image enhancement and denoising. Qualitative experiments, based on various general digital images and several T1- and T2-weighted magnetic resonance simulated images, show significant improvements when the RAAD algorithm is used versus the existing anisotropic diffusion and the previous forward and backward diffusion algorithms for enhancing edge features and improving image contrast. Quantitative analyses, based on peak signal-to-noise ratio, the universal image quality index, and the structural similarity confirm the superiority of the proposed algorithm.

  16. Fast spin echo vs conventional spin echo in cervical spine imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gillams, A.R.; Soto, J.A.; Carter, A.P. [Department of Radiology, Boston University Medical School and Boston City Hospital Imaging Foundation, Boston, MA 02118 (United States)

    1997-10-01

    The major attraction of fast-spin-echo (FSE) imaging is reduced acquisition time; however, careful review of the literature reveals many weaknesses: phase-encoded blurring, truncation artefact, bright fat signal, reduced magnetic susceptibility and increased motion artefact. Our aim was a prospective, blinded comparison of FSE and conventional spin echo (CSE) in the cervical spine. Both sequences were performed in 43 patients (19 males and 24 females; mean age 45 years, range 15-66 years). Twenty-eight patients were studied at 1.5 T and 15 at 0.5 T. Typical sequence parameters were: at 1.5 T, TR/TE 2000/90 CSE and 3000/120 FSE, and at 0.5 T, 2200/80 CSE and 2800/120 FSE. Time saved on the FSE was used to increase the matrix and the number of acquisitions. Two neuroradiologists evaluated the images for pathology, artefacts, disc signal intensity, thecal sac compression and image quality. Ten patients had cord lesions; 2 (20%) were missed on CSE. In 4 of 10 patients with moderate/severe thecal sac compression, the degree of stenosis was apparently exaggerated on CSE. The mean degree of confidence for the CSE sequences was 1.8 and for the FSE 1.1, where 1 is optimal. For cervical spine imaging, FSE should be preferred to CSE. (orig.). With 3 figs.

  17. A Comparison of PDE-based Non-Linear Anisotropic Diffusion Techniques for Image Denoising

    Energy Technology Data Exchange (ETDEWEB)

    Weeratunga, S K; Kamath, C

    2003-01-06

    PDE-based, non-linear diffusion techniques are an effective way to denoise images. In a previous study, we investigated the effects of different parameters in the implementation of isotropic, non-linear diffusion. Using synthetic and real images, we showed that for images corrupted with additive Gaussian noise, such methods are quite effective, leading to lower mean-squared-error values in comparison with spatial filters and wavelet-based approaches. In this paper, we extend this work to include anisotropic diffusion, where the diffusivity is a tensor valued function which can be adapted to local edge orientation. This allows smoothing along the edges, but not perpendicular to it. We consider several anisotropic diffusivity functions as well as approaches for discretizing the diffusion operator that minimize the mesh orientation effects. We investigate how these tensor-valued diffusivity functions compare in image quality, ease of use, and computational costs relative to simple spatial filters, the more complex bilateral filters, wavelet-based methods, and isotropic non-linear diffusion based techniques.

  18. Comparison of PDE-based non-linear anistropic diffusion techniques for image denoising

    Science.gov (United States)

    Weeratunga, Sisira K.; Kamath, Chandrika

    2003-05-01

    PDE-based, non-linear diffusion techniques are an effective way to denoise images.In a previous study, we investigated the effects of different parameters in the implementation of isotropic, non-linear diffusion. Using synthetic and real images, we showed that for images corrupted with additive Gaussian noise, such methods are quite effective, leading to lower mean-squared-error values in comparison with spatial filters and wavelet-based approaches. In this paper, we extend this work to include anisotropic diffusion, where the diffusivity is a tensor valued function which can be adapted to local edge orientation. This allows smoothing along the edges, but not perpendicular to it. We consider several anisotropic diffusivity functions as well as approaches for discretizing the diffusion operator that minimize the mesh orientation effects. We investigate how these tensor-valued diffusivity functions compare in image quality, ease of use, and computational costs relative to simple spatial filters, the more complex bilateral filters, wavelet-based methods, and isotropic non-linear diffusion based techniques.

  19. Tensor Based Representation and Analysis of Diffusion-Weighted Magnetic Resonance Images

    Science.gov (United States)

    Barmpoutis, Angelos

    2009-01-01

    Cartesian tensor bases have been widely used to model spherical functions. In medical imaging, tensors of various orders can approximate the diffusivity function at each voxel of a diffusion-weighted MRI data set. This approximation produces tensor-valued datasets that contain information about the underlying local structure of the scanned tissue.…

  20. Air-insufflated high-definition dacryoendoscopy yields significantly better image quality than conventional dacryoendoscopy.

    Science.gov (United States)

    Sasaki, Tsugihisa; Sounou, Tsutomu; Tsuji, Hideki; Sugiyama, Kazuhisa

    2017-01-01

    To facilitate the analysis of lacrimal conditions, we utilized high-definition dacryoendoscopy (HDD) and undertook observations with a pressure-controlled air-insufflation system. We report the safety and performance of HDD. In this retrospective, non-randomized clinical trial, 46 patients (14 males and 32 females; age range 39-91 years; mean age ± SD 70.3±12.0 years) who had lacrimal disorders were examined with HDD and conventional dacryoendoscopy (CD). The high-definition dacryoendoscope had 15,000 picture element image fibers and an advanced objective lens. Its outer diameter was 0.9-1.2 mm. Air insufflation was controlled at 0-20 kPa with a digital manometer-based pressure-controlled air-insufflation system to evaluate the quality of the image. The HDD had an air/saline irrigation channel between the outer sheath (outer diameter =1.2 mm) and the metal inner sheath of the endoscope. We used it and the CD in air, saline, and diluted milk saline with and without manual irrigation to quantitatively evaluate the effect of air pressure and saline irrigation on image quality. In vivo, the most significant improvement in image quality was demonstrated with air-insufflated (5-15 kPa) HDD, as compared with saline-irrigated HDD and saline-irrigated CD. No emphysema or damage was noted under observation with HDD. In vitro, no significant difference was demonstrated between air-insufflated HDD and saline-irrigated HDD. In vitro, the image quality of air-insufflated HDD was significantly improved as compared with that of saline-irrigated CD. Pressure-controlled (5-15 kPa) air-insufflated HDD is safe, and yields significantly better image quality than CD and saline-irrigated HDD.

  1. Shape-Based Image Matching Using Heat Kernels and Diffusion Maps

    Science.gov (United States)

    Vizilter, Yu. V.; Gorbatsevich, V. S.; Rubis, A. Yu.; Zheltov, S. Yu.

    2014-08-01

    2D image matching problem is often stated as an image-to-shape or shape-to-shape matching problem. Such shape-based matching techniques should provide the matching of scene image fragments registered in various lighting, weather and season conditions or in different spectral bands. Most popular shape-to-shape matching technique is based on mutual information approach. Another wellknown approach is a morphological image-to-shape matching proposed by Pytiev. In this paper we propose the new image-to-shape matching technique based on heat kernels and diffusion maps. The corresponding Diffusion Morphology is proposed as a new generalization of Pytiev morphological scheme. The fast implementation of morphological diffusion filtering is described. Experimental comparison of new and aforementioned shape-based matching techniques is reported applying to the TV and IR image matching problem.

  2. Effects of Orientation and Anisometry of Magnetic Resonance Imaging Acquisitions on Diffusion Tensor Imaging and Structural Connectomes

    Science.gov (United States)

    Muñoz-Moreno, Emma; López-Gil, Xavier; Soria, Guadalupe

    2017-01-01

    Diffusion-weighted imaging (DWI) quantifies water molecule diffusion within tissues and is becoming an increasingly used technique. However, it is very challenging as correct quantification depends on many different factors, ranging from acquisition parameters to a long pipeline of image processing. In this work, we investigated the influence of voxel geometry on diffusion analysis, comparing different acquisition orientations as well as isometric and anisometric voxels. Diffusion-weighted images of one rat brain were acquired with four different voxel geometries (one isometric and three anisometric in different directions) and three different encoding orientations (coronal, axial and sagittal). Diffusion tensor scalar measurements, tractography and the brain structural connectome were analyzed for each of the 12 acquisitions. The acquisition direction with respect to the main magnetic field orientation affected the diffusion results. When the acquisition slice-encoding direction was not aligned with the main magnetic field, there were more artifacts and a lower signal-to-noise ratio that led to less anisotropic tensors (lower fractional anisotropic values), producing poorer quality results. The use of anisometric voxels generated statistically significant differences in the values of diffusion metrics in specific regions. It also elicited differences in tract reconstruction and in different graph metric values describing the brain networks. Our results highlight the importance of taking into account the geometric aspects of acquisitions, especially when comparing diffusion data acquired using different geometries. PMID:28118397

  3. Altered brain microstructure assessed by diffusion tensor imaging in patients with chronic pancreatitis

    DEFF Research Database (Denmark)

    Frøkjær, Jens Brøndum; Olesen, Søren Schou; Gram, Mikkel

    2011-01-01

    Objective In patients with painful chronic pancreatitis (CP) there is increasing evidence of abnormal pain processing in the central nervous system. Using magnetic resonance (MR) diffusion tensor imaging, brain microstructure in areas involved in processing of visceral pain was characterised...

  4. Decomposition of Diffuse Reflectance Images - Features for Monitoring Structure in Turbid Media

    DEFF Research Database (Denmark)

    Skytte, Jacob Lercke; Nielsen, Otto Højager Attermann; Andersen, Ulf;

    2013-01-01

    we investigate different decomposition methods for extracting light scattering information from images of diffuse reflectance. Both well-established theoretical methods and data driven methods are considered and evaluated based on their robustness and sensitivity to changes in light scattering...

  5. Role of magnetic resonance diffusion imaging and apparent diffusion coefficient values in the evaluation of spinal tuberculosis in Indian patients

    Directory of Open Access Journals (Sweden)

    Palle Lalitha

    2010-01-01

    Full Text Available Aim: To define a range of apparent diffusion coefficient values in spinal tuberculosis and to evaluate the sensitivity of diffusion-weighted magnetic resonance imaging (DW-MRI and apparent diffusion coefficient values in patients of spinal tuberculosis. Materials and Methods: This study was conducted over a period of 20 months and included 110 patients with a total of 230 vertebral bodies. The study was performed in two parts. The first part included all patients of known tuberculosis and patients with classical features of tuberculosis. The second part included patients with spinal pathology of indeterminate etiology. All the patients underwent a routine MRI examination along with diffusion sequences. The apparent diffusion coefficient (ADC values were calculated from all the involved vertebral bodies. Results: The mean ADC value of affected vertebrae in first part of the study was found to be 1.4 ± 0.20 ×10 -3 mm 2 /s. This ADC value was then applied to patients in the second part of study in order to determine its ability in predicting tuberculosis. This range of ADC values was significantly different from the mean ADC values of normal vertebrae and those with metastatic involvement. However, there was an overlap of ADC values in a few tuberculous vertebrae with the ADC values in metastatic vertebrae. Conclusion: We found that DW-MRI and ADC values may help in the differentiation of spinal tuberculosis from other lesions of similar appearance. However, an overlap of ADC values was noted with those of metastatic vertebrae. Therefore diffusion imaging and ADC values must always be interpreted in association with clinical history and routine MRI findings and not in isolation.

  6. Optic radiation fiber tractography in glioma patients based on high angular resolution diffusion imaging with compressed sensing compared with diffusion tensor imaging - initial experience.

    Directory of Open Access Journals (Sweden)

    Daniela Kuhnt

    Full Text Available OBJECTIVE: Up to now, fiber tractography in the clinical routine is mostly based on diffusion tensor imaging (DTI. However, there are known drawbacks in the resolution of crossing or kissing fibers and in the vicinity of a tumor or edema. These restrictions can be overcome by tractography based on High Angular Resolution Diffusion Imaging (HARDI which in turn requires larger numbers of gradients resulting in longer acquisition times. Using compressed sensing (CS techniques, HARDI signals can be obtained by using less non-collinear diffusion gradients, thus enabling the use of HARDI-based fiber tractography in the clinical routine. METHODS: Eight patients with gliomas in the temporal lobe, in proximity to the optic radiation (OR, underwent 3T MRI including a diffusion-weighted dataset with 30 gradient directions. Fiber tractography of the OR using a deterministic streamline algorithm based on DTI was compared to tractography based on reconstructed diffusion signals using HARDI+CS. RESULTS: HARDI+CS based tractography displayed the OR more conclusively compared to the DTI-based results in all eight cases. In particular, the potential of HARDI+CS-based tractography was observed for cases of high grade gliomas with significant peritumoral edema, larger tumor size or closer proximity of tumor and reconstructed fiber tract. CONCLUSIONS: Overcoming the problem of long acquisition times, HARDI+CS seems to be a promising basis for fiber tractography of the OR in regions of disturbed diffusion, areas of high interest in glioma surgery.

  7. Assessment of 70-keV virtual monoenergetic spectral images in abdominal CT imaging: A comparison study to conventional polychromatic 120-kVp images.

    Science.gov (United States)

    Rassouli, Negin; Chalian, Hamid; Rajiah, Prabhakar; Dhanantwari, Amar; Landeras, Luis

    2017-04-18

    To evaluate the image quality of 70-keV virtual monoenergetic (monoE) abdominal CT images compared to 120-kVp polychromatic images generated from a spectral detector CT (SDCT) scanner. This prospective study included generation of a 120-kVp polychromatic dataset and a 70-keV virtual monoE dataset after a single contrast-enhanced CT acquisition on a SDCT scanner (Philips Healthcare) during portal venous phase. The attenuation values (HU), noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were measured in the liver, spleen, pancreas, kidney, aorta, portal vein, and muscle. The subjective image quality including noise, soft tissue contrast, sharpness, and overall image quality were graded on a 5-point Likert scale by two radiologists independently (1-worst image quality, 5-best image quality). Statistical analysis was performed using paired sample t test and Fleiss's Kappa. Fifty-five patients (54.3 ± 16.8 y/o; 28 M, 27 F) were recruited. The noise of target organs was significantly lower in virtual monoE images in comparison to polychromatic images (p virtual monoE images (p virtual monoE images was significantly better (p virtual monoE images, respectively. The inter-reader agreement for overall image quality was good (Kappa were 0.767 and 0.762 for polychromatic and virtual monoE images, respectively). In abdominal imaging, 70-keV virtual monoE CT images demonstrated significantly better noise, SNR, CNR, and subjective score compared to conventional 120-kVp polychromatic images.

  8. T2*-Weighted and Diffusion Magnetic Resonance Imaging Differentiation of Cerebral Fat Embolism From Diffuse Axonal Injury.

    Science.gov (United States)

    Rutman, Aaron M; Rapp, Elliot J; Hippe, Daniel S; Vu, Baoanh; Mossa-Basha, Mahmud

    2017-07-13

    This study differentiates cerebral fat embolism (CFE) and diffuse axonal injury (DAI) on diffusion-weighted magnetic resonance imaging (DWI) and T2*-weighted magnetic resonance imaging. Consecutive CFE and DAI cases were retrospectively selected. Hemorrhages were characterized by number, size/shape, and distribution, whereas DWI lesions by pattern. The number of hemorrhages was compared using the Mann-Whitney test with adjustment for multiple comparisons, whereas DWI abnormality was compared using Fisher exact test. Seven CFE and 20 DAI patients were included. Cerebral fat embolism had significantly more hemorrhages than DAI (mean, 670 ± 407 vs 136 ± 87; P = 0.01), particularly in the frontal (P = 0.025), parietal (P = 0.002), and occipital lobes (P = 0.01), the corpus callosum (P = 0.01), and cerebellum (P = 0.01). Cerebral fat embolism microhemorrhages were punctate/round, whereas DAI hemorrhages were small/medium sized (P CFE had confluent abnormalities (P CFE from DAI. Cerebral fat embolism demonstrates more hemorrhages. Larger or linear hemorrhages favor DAI. Diffuse confluent diffusion restriction favors CFE, whereas few scattered foci favor DAI.

  9. Quantitative thermal diffusivity imaging of disbonds in thermal protective coatings using inductive heating

    Science.gov (United States)

    Heath, D. M.; Winfree, William P.

    1990-01-01

    An inductive heating technique for making thermal diffusivity images of disbonds between thermal protective coatings and their substrates is presented. Any flaw in the bonding of the coating and the substrate shows as an area of lowered values in the diffusivity image. The benefits of the inductive heating approach lie in its ability to heat the conductive substrate without directly heating the dielectric coating. Results are provided for a series of samples with fabricated disbonds, for a range of coating thicknesses.

  10. Diffusion-weighted MR imaging of cystic lesions of neurocysticercosis: a preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Raffin, Luciana S.; Bacheschi, Luiz A.; Machado, Luis R.; Nobrega, Jose P.S.; Coelho, Christina; Leite, Claudia C. [Sao Paulo Univ., SP (Brazil). Faculdade de Medicina. Dept. de Neurologia]. E-mail: bacheschi@henet.usp.br

    2001-12-01

    Neurocysticercosis is an endemic disease in some developing countries. It has pleomorfic clinical and imaging findings, which are variable from patient to patient. In this preliminary note, we studied the magnetic resonance diffusion-weighted images of sixteen patients presenting with cystic lesions of this disease diagnosed by clinical and laboratorial findings. All the lesions had hypointense signal and the similar apparent diffusion coefficient values as the cerebrospinal fluid. (author)

  11. Diffusion Maps Clustering for Magnetic Resonance Q-Ball Imaging Segmentation

    Directory of Open Access Journals (Sweden)

    Demian Wassermann

    2008-01-01

    Full Text Available White matter fiber clustering aims to get insight about anatomical structures in order to generate atlases, perform clear visualizations, and compute statistics across subjects, all important and current neuroimaging problems. In this work, we present a diffusion maps clustering method applied to diffusion MRI in order to segment complex white matter fiber bundles. It is well known that diffusion tensor imaging (DTI is restricted in complex fiber regions with crossings and this is why recent high-angular resolution diffusion imaging (HARDI such as Q-Ball imaging (QBI has been introduced to overcome these limitations. QBI reconstructs the diffusion orientation distribution function (ODF, a spherical function that has its maxima agreeing with the underlying fiber populations. In this paper, we use a spherical harmonic ODF representation as input to the diffusion maps clustering method. We first show the advantage of using diffusion maps clustering over classical methods such as N-Cuts and Laplacian eigenmaps. In particular, our ODF diffusion maps requires a smaller number of hypothesis from the input data, reduces the number of artifacts in the segmentation, and automatically exhibits the number of clusters segmenting the Q-Ball image by using an adaptive scale-space parameter. We also show that our ODF diffusion maps clustering can reproduce published results using the diffusion tensor (DT clustering with N-Cuts on simple synthetic images without crossings. On more complex data with crossings, we show that our ODF-based method succeeds to separate fiber bundles and crossing regions whereas the DT-based methods generate artifacts and exhibit wrong number of clusters. Finally, we show results on a real-brain dataset where we segment well-known fiber bundles.

  12. Diffusion Maps Clustering for Magnetic Resonance Q-Ball Imaging Segmentation

    Science.gov (United States)

    Wassermann, Demian; Descoteaux, Maxime; Deriche, Rachid

    2008-01-01

    White matter fiber clustering aims to get insight about anatomical structures in order to generate atlases, perform clear visualizations, and compute statistics across subjects, all important and current neuroimaging problems. In this work, we present a diffusion maps clustering method applied to diffusion MRI in order to segment complex white matter fiber bundles. It is well known that diffusion tensor imaging (DTI) is restricted in complex fiber regions with crossings and this is why recent high-angular resolution diffusion imaging (HARDI) such as Q-Ball imaging (QBI) has been introduced to overcome these limitations. QBI reconstructs the diffusion orientation distribution function (ODF), a spherical function that has its maxima agreeing with the underlying fiber populations. In this paper, we use a spherical harmonic ODF representation as input to the diffusion maps clustering method. We first show the advantage of using diffusion maps clustering over classical methods such as N-Cuts and Laplacian eigenmaps. In particular, our ODF diffusion maps requires a smaller number of hypothesis from the input data, reduces the number of artifacts in the segmentation, and automatically exhibits the number of clusters segmenting the Q-Ball image by using an adaptive scale-space parameter. We also show that our ODF diffusion maps clustering can reproduce published results using the diffusion tensor (DT) clustering with N-Cuts on simple synthetic images without crossings. On more complex data with crossings, we show that our ODF-based method succeeds to separate fiber bundles and crossing regions whereas the DT-based methods generate artifacts and exhibit wrong number of clusters. Finally, we show results on a real-brain dataset where we segment well-known fiber bundles. PMID:18317506

  13. Nanoimprinted distributed feedback dye laser sensor for real-time imaging of small molecule diffusion

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Dufva, Martin; Kristensen, Anders

    2014-01-01

    Label-free imaging is a promising tool for the study of biological processes such as cell adhesion and small molecule signaling processes. In order to image in two dimensions of space current solutions require motorized stages which results in low imaging frame rates. Here, a highly sensitive...... of different grating periods which result in distinct laser emission wavelengths. Imaging in two dimensions of space is enabled by focusing an image of the laser surface with a cylindrical lens onto the entrance slit of an imaging spectrometer. Imaging is demonstrated by monitoring of diffusing small sucrose...

  14. Role of diffusion-weighted MR imaging in discrimination between the intracranial cystic masses

    Directory of Open Access Journals (Sweden)

    Ahmed Farid Yousef

    2014-09-01

    Results and conclusions: Patients in this study were categorized into three main groups; first group is brain abscesses (36 cases, 91.6% of them showed restricted diffusion, second group is malignant cystic or necrotic brain tumors, 28 cases of high grade necrotic glioma, 60.7% of them are free diffusion, and third group is benign cystic masses, arachnoid and epidermiod cysts (11 cases; all arachnoid cysts are free diffusion. From these results diffusion-weighted imaging is playing an important role in discrimination of cystic intracranial masses.

  15. Accuracy of reading liquid based cytology slides using the ThinPrep Imager compared with conventional cytology: prospective study

    Science.gov (United States)

    d'Assuncao, Jefferson; Irwig, Les; Macaskill, Petra; Chan, Siew F; Richards, Adele; Farnsworth, Annabelle

    2007-01-01

    Objective To compare the accuracy of liquid based cytology using the computerised ThinPrep Imager with that of manually read conventional cytology. Design Prospective study. Setting Pathology laboratory in Sydney, Australia. Participants 55 164 split sample pairs (liquid based sample collected after conventional sample from one collection) from consecutive samples of women choosing both types of cytology and whose specimens were examined between August 2004 and June 2005. Main outcome measures Primary outcome was accuracy of slides for detecting squamous lesions. Secondary outcomes were rate of unsatisfactory slides, distribution of squamous cytological classifications, and accuracy of detecting glandular lesions. Results Fewer unsatisfactory slides were found for imager read cytology than for conventional cytology (1.8% v 3.1%; Pcytology (7.4% v 6.0% overall and 2.8% v 2.2% for cervical intraepithelial neoplasia of grade 1 or higher). Among 550 patients in whom imager read cytology was cervical intraepithelial neoplasia grade 1 or higher and conventional cytology was less severe than grade 1, 133 of 380 biopsy samples taken were high grade histology. Among 294 patients in whom imager read cytology was less severe than cervical intraepithelial neoplasia grade 1 and conventional cytology was grade 1 or higher, 62 of 210 biopsy samples taken were high grade histology. Imager read cytology therefore detected 71 more cases of high grade histology than did conventional cytology, resulting from 170 more biopsies. Similar results were found when one pathologist reread the slides, masked to cytology results. Conclusion The ThinPrep Imager detects 1.29 more cases of histological high grade squamous disease per 1000 women screened than conventional cytology, with cervical intraepithelial neoplasia grade 1 as the threshold for referral to colposcopy. More imager read slides than conventional slides were satisfactory for examination and more contained low grade cytological

  16. Apparent Diffusion Coefficient (ADC) as a quantitative parameter in diffusion weighted MR imaging in gynecologic cancer: Dependence on b-values used

    DEFF Research Database (Denmark)

    Kallehauge, Jesper Folsted; Tanderup, Kari; Haack, Søren

    2010-01-01

    Diffusion weighted imaging (DWI) has gained interest as an imaging modality for assessment of tumor extension and response to cancer treatment. The purpose of this study is to assess the impact of the choice of b-values on the calculation of the Apparent Diffusion Coefficient (ADC) for locally ad...

  17. Diffusion tensor imaging detects Wallerian degeneration of the corticospinal tract early after cerebral infarction

    Institute of Scientific and Technical Information of China (English)

    Ruiman Xie; Min Fang; Linjiang Zhou; Shanghua Fan; Jianying Liu; Hongbo Quan; Man Luo; Dongying Qiu

    2012-01-01

    To investigate the feasibility and time window of early detection of Wallerian degeneration in the corticospinal tract after middle cerebral artery infarction, 23 patients were assessed using magnetic resonance diffusion tensor imaging at 3.0T within 14 days after the infarction. The fractional anisotropy values of the affected corticospinal tract began to decrease at 3 days after onset and decreased in all cases at 7 days. The diffusion coefficient remained unchanged. Experimental findings indicate that diffusion tensor imaging can detect the changes associated with Wallerian degeneration of the corticospinal tract as early as 3 days after cerebral infarction.

  18. Diffusion-Weighted MR imaging: Clinical applications of kurtosis analysis to prostate cancer

    CERN Document Server

    Barucci, Andrea; Esposito, Marco; Olmastroni, Maristella; Zatelli, Giovanna

    2016-01-01

    Magnetic resonance imaging technique known as DWI (diffusion-weighted imaging) allows measurement of water diffusivity on a pixel basis for evaluating pathology throughout the body and is now routinely incorporated into many body MRI protocols, mainly in oncology. Indeed water molecules motion reflects the interactions with other molecules, membranes, cells, and in general the interactions with the environment. Microstructural changes as e.g. cellular organization and/or integrity then affect the motion of water molecules, and consequently alter the water diffusion properties measured by DWI. Then DWI technique can be used to extract information about tissue organization at the cellular level indirectly from water motion. In general the signal intensity in DWI can be quantified by using a parameter known as ADC (Apparent Diffusion Coefficient) emphasizing that it is not the real diffusion coefficient, which is a measure of the average water molecular motion. In the simplest models, the distribu- tion of a wat...

  19. A time-efficient acquisition protocol for multipurpose diffusion-weighted microstructural imaging at 7 Tesla.

    Science.gov (United States)

    Sepehrband, Farshid; O'Brien, Kieran; Barth, Markus

    2017-02-12

    Several diffusion-weighted MRI techniques have been developed and validated during the past 2 decades. While offering various neuroanatomical inferences, these techniques differ in their proposed optimal acquisition design, preventing clinicians and researchers benefiting from all potential inference methods, particularly when limited time is available. This study reports an optimal design that enables for a time-efficient diffusion-weighted MRI acquisition scheme at 7 Tesla. The primary audience of this article is the typical end user, interested in diffusion-weighted microstructural imaging at 7 Tesla. We tested b-values in the range of 700 to 3000 s/mm(2) with different number of angular diffusion-encoding samples, against a data-driven "gold standard." The suggested design is a protocol with b-values of 1000 and 2500 s/mm(2) , with 25 and 50 samples, uniformly distributed over two shells. We also report a range of protocols in which the results of fitting microstructural models to the diffusion-weighted data had high correlation with the gold standard. We estimated minimum acquisition requirements that enable diffusion tensor imaging, higher angular resolution diffusion-weighted imaging, neurite orientation dispersion, and density imaging and white matter tract integrity across whole brain with isotropic resolution of 1.8 mm in less than 11 min. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  20. Time-optimized high-resolution readout-segmented diffusion tensor imaging.

    Directory of Open Access Journals (Sweden)

    Gernot Reishofer

    Full Text Available Readout-segmented echo planar imaging with 2D navigator-based reacquisition is an uprising technique enabling the sampling of high-resolution diffusion images with reduced susceptibility artifacts. However, low signal from the small voxels and long scan times hamper the clinical applicability. Therefore, we introduce a regularization algorithm based on total variation that is applied directly on the entire diffusion tensor. The spatially varying regularization parameter is determined automatically dependent on spatial variations in signal-to-noise ratio thus, avoiding over- or under-regularization. Information about the noise distribution in the diffusion tensor is extracted from the diffusion weighted images by means of complex independent component analysis. Moreover, the combination of those features enables processing of the diffusion data absolutely user independent. Tractography from in vivo data and from a software phantom demonstrate the advantage of the spatially varying regularization compared to un-regularized data with respect to parameters relevant for fiber-tracking such as Mean Fiber Length, Track Count, Volume and Voxel Count. Specifically, for in vivo data findings suggest that tractography results from the regularized diffusion tensor based on one measurement (16 min generates results comparable to the un-regularized data with three averages (48 min. This significant reduction in scan time renders high resolution (1 × 1 × 2.5 mm(3 diffusion tensor imaging of the entire brain applicable in a clinical context.

  1. A scale-based forward-and-backward diffusion process for adaptive image enhancement and denoising

    Directory of Open Access Journals (Sweden)

    Zhang Liangpei

    2011-01-01

    Full Text Available Abstract This work presents a scale-based forward-and-backward diffusion (SFABD scheme. The main idea of this scheme is to perform local adaptive diffusion using local scale information. To this end, we propose a diffusivity function based on the Minimum Reliable Scale (MRS of Elder and Zucker (IEEE Trans. Pattern Anal. Mach. Intell. 20(7, 699-716, 1998 to detect the details of local structures. The magnitude of the diffusion coefficient at each pixel is determined by taking into account the local property of the image through the scales. A scale-based variable weight is incorporated into the diffusivity function for balancing the forward and backward diffusion. Furthermore, as numerical scheme, we propose a modification of the Perona-Malik scheme (IEEE Trans. Pattern Anal. Mach. Intell. 12(7, 629-639, 1990 by incorporating edge orientations. The article describes the main principles of our method and illustrates image enhancement results on a set of standard images as well as simulated medical images, together with qualitative and quantitative comparisons with a variety of anisotropic diffusion schemes.

  2. Image Corruption Detection in Diffusion Tensor Imaging for Post-Processing and Real-Time Monitoring

    Science.gov (United States)

    Li, Yue; Shea, Steven M.; Lorenz, Christine H.; Jiang, Hangyi; Chou, Ming-Chung; Mori, Susumu

    2013-01-01

    Due to the high sensitivity of diffusion tensor imaging (DTI) to physiological motion, clinical DTI scans often suffer a significant amount of artifacts. Tensor-fitting-based, post-processing outlier rejection is often used to reduce the influence of motion artifacts. Although it is an effective approach, when there are multiple corrupted data, this method may no longer correctly identify and reject the corrupted data. In this paper, we introduce a new criterion called “corrected Inter-Slice Intensity Discontinuity” (cISID) to detect motion-induced artifacts. We compared the performance of algorithms using cISID and other existing methods with regard to artifact detection. The experimental results show that the integration of cISID into fitting-based methods significantly improves the retrospective detection performance at post-processing analysis. The performance of the cISID criterion, if used alone, was inferior to the fitting-based methods, but cISID could effectively identify severely corrupted images with a rapid calculation time. In the second part of this paper, an outlier rejection scheme was implemented on a scanner for real-time monitoring of image quality and reacquisition of the corrupted data. The real-time monitoring, based on cISID and followed by post-processing, fitting-based outlier rejection, could provide a robust environment for routine DTI studies. PMID:24204551

  3. Image corruption detection in diffusion tensor imaging for post-processing and real-time monitoring.

    Science.gov (United States)

    Li, Yue; Shea, Steven M; Lorenz, Christine H; Jiang, Hangyi; Chou, Ming-Chung; Mori, Susumu

    2013-01-01

    Due to the high sensitivity of diffusion tensor imaging (DTI) to physiological motion, clinical DTI scans often suffer a significant amount of artifacts. Tensor-fitting-based, post-processing outlier rejection is often used to reduce the influence of motion artifacts. Although it is an effective approach, when there are multiple corrupted data, this method may no longer correctly identify and reject the corrupted data. In this paper, we introduce a new criterion called "corrected Inter-Slice Intensity Discontinuity" (cISID) to detect motion-induced artifacts. We compared the performance of algorithms using cISID and other existing methods with regard to artifact detection. The experimental results show that the integration of cISID into fitting-based methods significantly improves the retrospective detection performance at post-processing analysis. The performance of the cISID criterion, if used alone, was inferior to the fitting-based methods, but cISID could effectively identify severely corrupted images with a rapid calculation time. In the second part of this paper, an outlier rejection scheme was implemented on a scanner for real-time monitoring of image quality and reacquisition of the corrupted data. The real-time monitoring, based on cISID and followed by post-processing, fitting-based outlier rejection, could provide a robust environment for routine DTI studies.

  4. The role of diffusion weighted magnetic resonance imaging in ...

    African Journals Online (AJOL)

    Shaimaa R.A. Fadeel

    2015-06-16

    Jun 16, 2015 ... assessment of normal myelination development in the infantile brain and matches the results of con- ventional MRI. ... It is useful to characterize myelination evolution in normal brain .... tion gap, 2.5 mm; field of view, 20 cm; matrix size, 128_128; ..... Normal brain in human newborns: apparent diffusion.

  5. Diffusion tensor imaging of the brain in patients with Alzheimer's disease and cerebrovascular lesions

    Institute of Scientific and Technical Information of China (English)

    CHEN Shao-qiong; KANG Zhuang; HU Xi-quan; HU Bing; ZOU Yan

    2007-01-01

    Background: Recent autopsy study showed a high incidence ofcerebrovascular lesions in Alzheimer's disease (AD).To assess the impact of cerebrovascular pathology in AD, we used diffusion tensor imaging (DTI) to study AD patients with and without cerebrovascular lesions. Materials and Methods: Conventional and DTI scans were obtained from 10 patients with probable AD, 10 AD/V patients (probable AD with cerebrovascular lesions) and ten normal controls. Mean diffusivity (D) and fractional anisotropy (FA) values of some structures involved with AD pathology were measured. Results: D value was higher in AD patients than in controls in hippocampus and the cingulate gyrus. In AD/V patients, increased D value was found in the same structures and also in the thalamus and basal ganglia compared to controls. There was a significant difference of D value between AD and AD/V patients. FA value reduced in the white matter of left inferior temporal gyrus and in the bilateral middle cingulate gyrus in patients with AD/V compared with controls. The MMSE (mini-mental state examination) score significantly correlated with FA value in the right hippocampus (r=0.639, P<0.019), in the right anterior cingulate gyrus (r=0.587, P<0.035) and in left parahippocampal gyrus (r=0.559, P<0.047). Conclusion: Cerebrovascular pathology had stronger impact on the D value than the AD pathology alone did. Elevated D value in thalamic and basal ganglia may contribute to cognitive decline in AD/V patients.Reduced FA values in AD/V patients may indicate that cerebrovascular pathology induced more severe white matter damage than the AD pathology alone did.

  6. (18)F Fluorocholine PET/MR Imaging in Patients with Primary Hyperparathyroidism and Inconclusive Conventional Imaging: A Prospective Pilot Study.

    Science.gov (United States)

    Kluijfhout, Wouter P; Pasternak, Jesse D; Gosnell, Jessica E; Shen, Wen T; Duh, Quan-Yang; Vriens, Menno R; de Keizer, Bart; Hope, Thomas A; Glastonbury, Christine M; Pampaloni, Miguel H; Suh, Insoo

    2017-01-25

    Purpose To investigate the performance of flourine 18 ((18)F) fluorocholine (FCH) positron emission tomography (PET)/magnetic resonance (MR) imaging in patients with hyperparathyroidism and nonlocalized disease who have negative or inconclusive results at ultrasonography (US) and technetium 99m ((99m)Tc) sestamibi scintigraphy. Materials and Methods This study was approved by the institutional review board. Between May and December 2015, 10 patients (mean age, 70.4 years; range, 58-82 years) with biochemical primary hyperparathyroidism and inconclusive results at US and (99m)Tc sestamibi scintigraphy were prospectively enrolled. All patients gave informed consent. Directly after administration of 3 MBq/kg of FCH, PET imaging was performed, followed by T1- and T2-weighted MR imaging before and after gadolinium enhancement. Intraoperative localization and histologic results were the reference standard for calculating sensitivity and positive predictive value. The Wilcoxon rank test was used to calculate the mean difference in maximum standardized uptake value (SUVmax) between abnormal parathyroid uptake and physiologic thyroid uptake. The Wilcoxon rank-sum test was performed. Results MR imaging alone showed true-positive lesions in five patients and a false-positive lesion in one patient. FCH PET/MR imaging allowed correct localization of nine of 10 adenomas (90% sensitivity), without any false-positive results (100% positive predictive value). One patient had four-gland hyperplasia, of which three hyperplastic glands were not localized. The median SUVmax of the nine preoperatively identified adenomas was 4.9 (interquartile range, 2.45-7.35), which was significantly higher than the SUV, 2.7 (interquartile range, 1.6-3.8), of the thyroid (P = .008). Conclusion FCH PET/MR imaging allowed localization of adenomas with high accuracy when conventional imaging results were inconclusive and provided detailed anatomic information. More patients must be examined to confirm

  7. In vivo measurement of water self diffusion in the human brain by magnetic resonance imaging

    DEFF Research Database (Denmark)

    Thomsen, C; Henriksen, O; Ring, P

    1987-01-01

    A new pulse sequence for in vivo diffusion measurements by magnetic resonance imaging (MRI) is introduced. The pulse sequence was tested on phantoms to evaluate the accuracy, reproducibility and inplane variations. The sensitivity of the sequence was tested by measuring the self diffusion...... between grey and white matter as well as regional differences within the white matter were seen. In two patients with infarction, alternations in water self diffusion were seen in the region of the infarct. Likewise, pronounced changes in brain water self diffusion were observed in a patient with benign...... intracranial hypertension. The results indicate that brain water self diffusion can be measured in vivo with reasonable accuracy. The clinical examples suggest that diffusion measurements may be clinically useful adding further information about in vivo MR tissue characterization....

  8. Comparison of magnetic resonance imaging and conventional neuroradiographies in lumbar herniated nucleus pulposus

    Energy Technology Data Exchange (ETDEWEB)

    Nishijima, Yuichiro; Taniguchi, Mitsukazu; Michishita, Masamitsu; Ohta, Yoshiaki; Kondo, Takeshi; Tonami, Hisao; Yamazaki, Yasuro; Higashida, Norihiko; Yamamoto, Tatsu (Kanazawa Medical Univ., Ishikawa (Japan))

    1992-03-01

    To determine whether magnetic resonance imaging (MRI) would replace conventional neuroradiographies in lumbar herniated nucleus pulposus, preoperative MRI findings were compared with surgery-confirmed pathophysiology of 63 intervertebral disks in 58 patients. Conventional neuroradiographies consisted of myelography, CT myelography, discography, and CT discography. Pathophysiology of 63 herniated disks fall into normal (n=7), bulging (n=9), protrusion (n=14), extrusion (n=17), and free migrated (n=16). Diagnostic accuracy of MRI was evaluated in terms of the presence or absence of herniation, height, location, and morphology of herniated disk. In diagnosing herniation, MRI had a sensitivity of 96%, a specificity of 25%, and an accuracy of 78%. In determining the height of herniated disk, the diagnostic rate of MRI was 77%, being lower than both CT myelography (94%) and CT discography (89%). MRI had a concordance rate of 55% for bilateral location in transaxial view, compared with 76% for CT myelography and 74% for CT discography. MRI failed to differentiate extrusion from protrusion. In conclusion, MRI was the most suitable for screening the presence or absence of herniation; however, it was inferior to other neuroradiographies in the diagnosis of morphology of herniated disk, as well as the determination of height and surgical intervention site of herniated disk. (N.K.).

  9. Peritumoral edema of meningiomas and metastatic brain tumors: differences in diffusion characteristics evaluated with diffusion-tensor MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Toh, Cheng-Hong; Wong, Alex M.-C; Wong, Ho-Fai; Wan, Yung-Liang [Chang Gung Memorial Hospital, Department of Medical Imaging and Intervention, Tao-Yuan (China); Chang Gung University, School of Medicine and Medical Technology, Tao-Yuan (China); Wei, Kuo-Chen [Chang Gung Memorial Hospital, Department of Neurosurgery, Tao-Yuan (China); Chang Gung University, School of Medicine and Medical Technology, Tao-Yuan (China); Ng, Shu-Hang [Chang Gung Memorial Hospital, Department of Medical Imaging and Intervention, Tao-Yuan (China); Chang Gung University, School of Medicine and Medical Technology, Tao-Yuan (China); Chang Gung Memorial Hospital, Molecular Image Center, Tao-Yuan (China)

    2007-06-15

    We prospectively compared the fractional anisotropy (FA) and mean diffusivity (MD) of the peritumoral edema of meningiomas and metastatic brain tumors with diffusion-tensor magnetic resonance (MR) imaging. The study protocol was approved by the local ethics committee, and written informed consent was obtained. Preoperative diffusion-tensor MR imaging was performed in 15 patients with meningiomas and 11 patients with metastatic brain tumors. Regions of interest (ROI) were placed in the peritumoral edema and normal-appearing white matter (NAWM) of the contralateral hemisphere to measure the FA and MD. The FA and MD ratios were calculated for each ROI in relation to the NAWM of the contralateral hemisphere. Changes in peritumoral MD and FA, in terms of primary values and ratios, were compared using a two-sample t-test; P < 0.05 was taken as indicating statistical significance. The mean MD values (x 10{sup -3} mm{sup 2}/s) of the peritumoral edema for metastases and meningiomas, respectively, were 0.902 {+-} 0.057 and 0.820 {+-} 0.094, the mean MD ratios were 220.3 {+-} 22.6 and 193.1 {+-} 23.4, the mean FA values were 0.146 {+-} 0.026 and 0.199 {+-} 0.052, and the mean FA ratios were 32.3 {+-} 5.9 and 46.0 {+-} 12.1. All the values were significantly different between metastases and meningiomas (MD values P = 0.016, MD ratios P = 0.006, FA values P = 0.005, FA ratios P = 0.002). The peritumoral edema of metastatic brain tumors and meningiomas show different MD and FA on diffusion-tensor MR imaging. (orig.)

  10. Fast diffusion tensor imaging and tractography of the whole cervical spinal cord using point spread function corrected echo planar imaging

    DEFF Research Database (Denmark)

    Lundell, Hans Magnus Henrik; Barthelemy, Dorothy; Biering-Sørensen, Fin

    2013-01-01

    Diffusion tensor imaging has been used in a number of spinal cord studies, but severe distortions caused by susceptibility induced field inhomogeneities limit its applicability to investigate small volumes within acceptable acquisition times. A way to evaluate image distortions is to map the poin...... artifacts or in high-field imaging settings where off-resonance effects are pronounced. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc....

  11. Diffusion tensor MR imaging evaluation of the corpus callosum of patients with multiple sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Rueda, Fernanda [Hospital Universitario Clementino Fraga Filho, Rio de Janeiro, RJ (Brazil). Servico de Radiodiagnostico; Hygino Junior, Luiz Celso; Vasconcelos, Claudia C. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Programa de Pos-Graduacao em Medicina (Radiologia); Domingues, Romeu Cortes [Clinica de Diagnostico Por Imagem e Multi-Imagem (CDPI), Rio de Janeiro, RJ (Brazil); Papais-Alvarenga, Regina M. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Gasparetto, Emerson L. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Faculdade de Medicina. Dept. de Radiologia]. E-mail: egasparetto@gmail.com

    2008-07-01

    Objective: To evaluate the fractional anisotropy (FA) values of the normal-appearing white matter of the corpus callosum (CC) in patients with relapsing-remitting multiple sclerosis (MS). Method: Fifty-seven patients with diagnosis of relapsing-remitting MS and 47 age- and gender-matched controls were studied. A conventional MR imaging protocol and a DTI sequence were performed. One neuro radiologist placed the regions of interest (ROIs) in the FA maps in five different portions of the normal-appearing CC (rostrum, genu, anterior and posterior portion of the body and splenium) in all cases. The statistical analysis was performed with the Mann-Whitney U test and p<0.05 was considered statistically significant. Results: The FA values were lower in the MS patients compared with the controls (p<0.05) in the following CC regions: rostrum (0.720 vs 0.819), anterior body (0.698 vs 0.752), posterior body (0.711 vs 0.759) and splenium (0.720 vs 0.880). Conclusion: In this series, there was a robust decrease in the FA in all regions of the normal-appearing CC, being significant in the rostrum, body and splenium. This finding suggests that there is a subtle and diffuse abnormality in the CC, which could be probably related to myelin content loss, axonal damage and gliosis. (author)

  12. Use of diffusion and perfusion magnetic resonance imaging as a tool in acute stroke clinical trials

    Directory of Open Access Journals (Sweden)

    Warach Steven

    2001-01-01

    Full Text Available Abstract In light of the slow progress in developing effective therapies for ischemic stroke, magnetic resonance imaging techniques have emerged as new tools in stroke clinical trials. Rapid imaging with magnetic resonance imaging, diffusion weighted imaging, perfusion imaging and angiography are being incorporated into phase II and phase III stroke trials to optimize patient selection based on positive imaging diagnosis of the ischemic pathophysiology specifically related to a drug's mechanism of action and as a direct biomarker of the effect of a treatment's effect on the brain.

  13. Characterization of normal brain and brain tumor pathology by chisquares parameter maps of diffusion-weighted image data

    Energy Technology Data Exchange (ETDEWEB)

    Maier, Stephan E. E-mail: stephan@bwh.harvard.edu; Mamata, Hatsuho; Mulkern, Robert V

    2003-03-01

    Objective: To characterize normal and pathologic brain tissue by quantifying the deviation of diffusion-related signal from a simple monoexponential decay, when measured over a wider than usual range of b-factors. Methods and materials: Line scan diffusion imaging (LSDI), with diffusion weighting at multiple b-factors between 100 and 5000 s/mm{sup 2}, was performed on 1.5 T clinical scanners. Diffusion data of single slice sections were acquired in five healthy subjects and 19 brain tumor patients. In-patients, conventional T2-weighted and contrast-enhanced T1-weighted images were obtained for reference purposes. The chisquare ({chi}{sup 2}) error parameter associated with the monoexponential fits of the measured tissue water signals was then used to quantify the departure from a simple monoexponential signal decay on a pixel-by-pixel basis. Results: Diffusion-weighted images over a wider b-factor range than typically used were successfully obtained in all healthy subjects and patients. Normal and pathologic tissues demonstrated signal decays, which clearly deviate from a simple monoexponential behavior. The {chi}{sup 2} of cortical and deep grey matter was considerably lower than in white matter. In peritumoral edema, however, {chi}{sup 2} was 68% higher than in normal white matter. In highly malignant brain tumors, such as glioblastoma multiforme (GBM) or anaplastic astrocytoma, {chi}{sup 2} values were on average almost 400% higher than in normal white matter, while for one low grade astrocytoma and two cases of metastasis, {chi}{sup 2} was not profoundly different from the {chi}{sup 2} value of white matter. Maps of the {chi}{sup 2} values provide good visualization of spatial details. However, the tumor tissue contrast generated appeared in many cases to be different from the enhancement produced by paramagnetic contrast agents. For example, in cases where the contrast agent only highlighted the rim of the tumor, {chi}{sup 2} enhancement was present within the

  14. Hypercellularity Components of Glioblastoma Identified by High b-Value Diffusion-Weighted Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Pramanik, Priyanka P. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Parmar, Hemant A. [Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Mammoser, Aaron G.; Junck, Larry R. [Department of Neurology, University of Michigan, Ann Arbor, Michigan (United States); Kim, Michelle M.; Tsien, Christina I.; Lawrence, Theodore S. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Cao, Yue, E-mail: yuecao@med.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)

    2015-07-15

    Purpose: Use of conventional magnetic resonance imaging (MRI) for target definition may expose glioblastomas (GB) to inadequate radiation dose coverage of the nonenhanced hypercellular subvolume. This study aimed to develop a technique to identify the hypercellular components of GB by using high b-value diffusion-weighted imaging (DWI) and to investigate its relationship with the prescribed 95% isodose volume (PDV) and progression-free survival (PFS). Methods and Materials: Twenty-one patients with GB underwent chemoradiation therapy post-resection and biopsy. Radiation therapy (RT) treatment planning was based upon conventional MRI. Pre-RT DWIs were acquired in 3 orthogonal directions with b-values of 0, 1000, and 3000 s/mm{sup 2}. Hypercellularity volume (HCV) was defined on the high b-value (3000 s/mm{sup 2}) DWI by a threshold method. Nonenhanced signified regions not covered by the Gd-enhanced gross tumor volume (GTV-Gd) on T1-weighted images. The PDV was used to evaluate spatial coverage of the HCV by the dose plan. Association between HCV and PFS or other clinical covariates were assessed using univariate proportional hazards regression models. Results: HCVs and nonenhanced HCVs varied from 0.58 to 67 cm{sup 3} (median: 9.8 cm{sup 3}) and 0.15 to 60 cm{sup 3} (median: 2.5 cm{sup 3}), respectively. Fourteen patients had incomplete dose coverage of the HCV, 6 of whom had >1 cm{sup 3} HCV missed by the 95% PDV (range: 1.01-25.4 cm{sup 3}). Of the 15 patients who progressed, 5 progressed earlier, within 6 months post-RT, and 10 patients afterward. Pre-RT HCVs within recurrent GTVs-Gd were 78% (range: 65%-89%) for the 5 earliest progressions but lower, 53% (range: 0%-85%), for the later progressions. HCV and nonenhanced HCV were significant negative prognostic indicators for PFS (P<.002 and P<.01, respectively). The hypercellularity subvolume not covered by the 95% PDV was a significant negative predictor for PFS (P<.05). Conclusions: High b-value DWI

  15. 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.

  16. Performance characteristics of UV imaging instrumentation for diffusion, dissolution and release testing studies

    DEFF Research Database (Denmark)

    Jensen, Sabrine S; Jensen, Henrik; Goodall, David M

    2016-01-01

    UV imaging is capable of providing spatially and temporally resolved absorbance measurements, which is highly beneficial in drug diffusion, dissolution and release testing studies. For optimal planning and design of experiments, knowledge about the capabilities and limitations of the imaging system...

  17. Diffusion tensor imaging of peripheral nerves in non-fixed post-mortem subjects

    NARCIS (Netherlands)

    Haakma, Wieke; Pedersen, Michael; Froeling, Martijn; Uhrenholt, Lars; Leemans, Alexander; Boel, Lene Warner Thorup

    2016-01-01

    Purpose: While standard magnetic resonance imaging (MRI) sequences are increasingly employed in post-mortem (PM) examinations, more advanced techniques such as diffusion tensor imaging (DTI) remain unexplored in forensic sciences. Therefore, we studied the temporal stability and reproducibility of D

  18. DCT-Based Characterization of Milk Products Using Diffuse Reflectance Images

    DEFF Research Database (Denmark)

    Sharifzadeh, Sara; Skytte, Jacob Lercke; Clemmensen, Line Katrine Harder;

    2013-01-01

    We propose to use the two-dimensional Discrete Cosine Transform (DCT) for decomposition of diffuse reflectance images of laser illumination on milk products in different wavelengths. Based on the prior knowledge about the characteristics of the images, the initial feature vectors are formed at ea...

  19. Diffusion-weighted imaging and cognition in the leukoariosis and disability in the elderly study

    DEFF Research Database (Denmark)

    Schmidt, Reinhold; Ropele, Stefan; Ferro, José;

    2010-01-01

    role. METHODS: In addition to a comprehensive clinical, neuropsychologic, and imaging work-up, diffusion-weighted imaging was performed in 340 participants of the multicenter leukoariosis and disability study examining the impact of white matter hyperintensities (WMH) on 65- to 85-year old individuals...

  20. A Diffusion Tensor Imaging Study on the Auditory System and Tinnitus

    NARCIS (Netherlands)

    Crippa, Alessandro; Lanting, Cris; Dijk, Pim van; Roerdink, Jos B.T.M.

    2010-01-01

    Tinnitus is an auditory percept in the absence of an external sound source. Mechanisms in the central nervous system are believed to be key in the pathophysiology of tinnitus. Diffusion tensor imaging (DTI) is an MR imaging technique that allows in vivo exploration of white matter tissue in the

  1. Unifying the analyses of anatomical and diffusion tensor images using volume-preserved warping

    DEFF Research Database (Denmark)

    Xu, Dongrong; Hao, Xuejun; Bansal, Ravi

    2007-01-01

    PURPOSE: To introduce a framework that automatically identifies regions of anatomical abnormality within anatomical MR images and uses those regions in hypothesis-driven selection of seed points for fiber tracking with diffusion tensor (DT) imaging (DTI). MATERIALS AND METHODS: Regions of interest...

  2. Diffusion Tensor Imaging Correlates of Reading Ability in Dysfluent and Non-Impaired Readers

    Science.gov (United States)

    Lebel, Catherine; Shaywitz, Bennett; Holahan, John; Shaywitz, Sally; Marchione, Karen; Beaulieu, Christian

    2013-01-01

    Many children and adults have specific reading disabilities; insight into the brain structure underlying these difficulties is evolving from imaging. Previous research highlights the left temporal-parietal white matter as important in reading, yet the degree of involvement of other areas remains unclear. Diffusion tensor imaging (DTI) and…

  3. Diffusion-weighted imaging outside the brain: Consensus statement from an ISMRM-sponsored workshop.

    Science.gov (United States)

    Taouli, Bachir; Beer, Ambros J; Chenevert, Thomas; Collins, David; Lehman, Constance; Matos, Celso; Padhani, Anwar R; Rosenkrantz, Andrew B; Shukla-Dave, Amita; Sigmund, Eric; Tanenbaum, Lawrence; Thoeny, Harriet; Thomassin-Naggara, Isabelle; Barbieri, Sebastiano; Corcuera-Solano, Idoia; Orton, Matthew; Partridge, Savannah C; Koh, Dow-Mu

    2016-09-01

    The significant advances in magnetic resonance imaging (MRI) hardware and software, sequence design, and postprocessing methods have made diffusion-weighted imaging (DWI) an important part of body MRI protocols and have fueled extensive research on quantitative diffusion outside the brain, particularly in the oncologic setting. In this review, we summarize the most up-to-date information on DWI acquisition and clinical applications outside the brain, as discussed in an ISMRM-sponsored symposium held in April 2015. We first introduce recent advances in acquisition, processing, and quality control; then review scientific evidence in major organ systems; and finally describe future directions. J. Magn. Reson. Imaging 2016;44:521-540.

  4. Effects of spatially heterogeneous porosity on matrix diffusion as investigated by X-ray absorption imaging

    Science.gov (United States)

    Tidwell, Vincent C.; Meigs, Lucy C.; Christian-Frear, Tracy; Boney, Craig M.

    2000-03-01

    High-resolution X-ray absorption imaging was used to investigate the effects of spatially heterogeneous porosity on matrix diffusion. Experiments were performed on four, centimeter-scale slabs of Culebra dolomite taken from the Waste Isolation Pilot Plant (WIPP) site. These tests involved the diffusion of potassium iodide into a single edge of each brine-saturated rock slab, while X-ray absorption imaging was used to measure the two-dimensional relative concentration distribution at different times during the experiment. X-ray imaging was also used to measure the heterogeneous, two-dimensional porosity distribution of each rock slab. The resulting high-resolution data provide unique insight into the spatially varying diffusion characteristics of each heterogeneous rock sample, which traditional methods such as through-diffusion experiments cannot. In these tests, significant variations in the diffusion coefficient were calculated over the relatively small length (centimeter) and time scales (months) investigated. Results also indicated that these variations were related to the heterogeneous porosity characteristics of each rock sample. Not only were the diffusion coefficients found to depend on the magnitude of the porosity but also on its spatial distribution. Specifically, the geometry, position, and orientation of the heterogeneous porosity features populating each rock slab appeared to influence the diffusion characteristics.

  5. Topographic distribution and characteristics of normal gastric regional lymph nodes on diffusion-weighted magnetic resonance imaging.

    Science.gov (United States)

    Mao, Yun; Hedgire, Sandeep S; Liao, Gang; Lv, Fajin; Li, Yongmei; Li, Qi; Wang, Ziwei

    2016-02-01

    Current lack of recognition of normal gastric regional lymph nodes (GRLNs) and inherent defect of morphological imaging limit the accuracy of preoperative nodal (N) staging of gastric cancer. To map the distribution of normal GRLNs and evaluating the characteristics of GRLNs with diffusion-weighted imaging (DWI) in healthy population. Forty-nine enrolled healthy volunteers were divided into two age groups and underwent conventional magnetic resonance imaging (MRI) and DWI examinations. The characteristics of GRLNs in 14 regional stations, including short axis diameter (SD), short-to-long axis diameter ratio (SLR), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC), were recorded and compared between age groups and among different stations. The normal GRLNs were mainly distributed in station 7 in both age groups, followed by stations 3, 8, and 9. The SLR was lower in the young group than in the old group (P = 0.034) while SD, SNR, CNR, and ADC were significantly higher in the young group compared to the old group, P = 0.045, 0.041, 0.037, and 0.042, respectively. SD was different among stations in both age groups (P = 0.002, 0.001), especially bigger in station 8, and the SNRs and CNRs of stations 8 and 9 were relatively high in the old group (P = 0.031, 0.035), while there was no difference in ADC value. Better understanding of the appearances of normal GRLNs on conventional MRI and DWI may help to build more appropriate imaging criteria for GRLN assessment in gastric cancer. © The Foundation Acta Radiologica 2015.

  6. Edge-Aware Level Set Diffusion and Bilateral Filtering Reconstruction for Image Magnification

    Institute of Scientific and Technical Information of China (English)

    Hua Huang; Yu Zang; Paul L.Rosin; Chun Qi

    2009-01-01

    In this paper we propose an image magnification reconstruction method. In recent years many interpolation algorithms have been proposed for image magnification, but all of them have defects to some degree, such as jaggies and blurring. To solve these problems, we propose applying post-processing which consists of edge-aware level set diffusion and bilateral filtering. After the initial interpolation, the contours of the image are identified. Next, edge-aware level set diffusion is applied to these significant contours to remove the jaggies, followed by bilateral filtering at the same locations to reduce the blurring created by the initial interpolation and level set diffusion. These processes produce sharp contours without jaggies and preserve the details of the image. Results show that the overall RMS error of our method barely increases while the contour smoothness and sharpness are substantially improved.

  7. Real-time vessel image enhancement system with forward and backward diffusion based on DSP

    Science.gov (United States)

    Zhang, Zhao; Wang, An; Sun, Jian-Zhao; Xia, Ying-Wei; Zhang, Long; Liu, Yong

    2016-10-01

    In order to help medical personnel to make accurate clinical judgment, we built a DSP real-time image enhancement system to enhance and sharpening the hand vein distribution image. First, we use 760 nm and 960 nm mixed near-infrared light as the light source to decrease the skin scattering and absorption of the incident light, and gain a distinct original image. Then, we analyzed the vascular model in the multi-scale method, and using the vascular response function to take the place of gradient in diffusion equation, constructed the Forward And Backward Diffusion (FABD) coefficients. Then, we realized it in the DM642 DSP hardware platform; finally, the proposed enhancement algorithms implemented on the hardware platform, and compared with anisotropic diffusion algorithm and forward and backward diffusion algorithm. The results showed that, the proposed system to enhance the images standard deviation than the original increased by 11.4971, and increased by 2.2530 and 1.1500 than the anisotropic diffusion algorithm and forward and backward diffusion algorithm respectively. The proposed system's processing time was 28.0ms, and met real time requirements. The system was stable, reliable and met the medical needs.

  8. Magnetic resonance diffusion tensor imaging and tractography of the lower spinal cord: application to diastematomyelia and tethered cord

    Energy Technology Data Exchange (ETDEWEB)

    Filippi, Christopher G.; Gonyea, Jay V.; Linnell, Grant [University of Vermont College of Medicine, Department of Radiology, Fletcher Allen Healthcare, Burlington, VT (United States); Andrews, Trevor [University of Vermont College of Medicine, Department of Radiology, Fletcher Allen Healthcare, Burlington, VT (United States); Philips Healthcare, Highland Heights, OH (United States); Cauley, Keith A. [University of Massachusetts Medical Center, Department of Radiology, Division of Neuroradiology, Worcester, MA (United States)

    2010-09-15

    To investigate the feasibility of routine clinical DTI of the lower spinal cord using high-field-strength MRI and parallel imaging, and to evaluate the utility of diffusion tensor imaging and tractography as tools for study of lower cord pathology. Three patients with diastematomyelia, one patient with tethered cord, and six normal volunteers underwent MR imaging of the lower spine at 3 T. A 15-channel spine coil and parallel imaging were used with a six-direction single-shot echo-planar gradient echo technique. In normal volunteers, tractography delineated the conus and cauda equina. Tractography software permitted assessment of fractional anisotropy of the distal cord and nerve roots. In cases of tethered cord, tractography correlated with anatomical imaging. Tractography also correlated with the anatomical pathological findings in cases of diastematomyelia. The methods described enable routine DTI and tractography of the lower spinal cord at 3 T. Compared with conventional imaging, tractography offers additional information that may prove useful in the characterization and surgical planning for congenital lesions involving the lower spinal cord. (orig.)<