Structural layers of ex vivo rat hippocampus at 7T MRI.

Directory of Open Access Journals (Sweden)

Jeanine Manuella Kamsu

Full Text Available Magnetic resonance imaging (MRI applied to the hippocampus is challenging in studies of the neurophysiology of memory and the physiopathology of numerous diseases such as epilepsy, Alzheimer's disease, ischemia, and depression. The hippocampus is a well-delineated cerebral structure with a multi-layered organization. Imaging of hippocampus layers is limited to a few studies and requires high magnetic field and gradient strength. We performed one conventional MRI sequence on a 7T MRI in order to visualize and to delineate the multi-layered hippocampal structure ex vivo in rat brains. We optimized a volumic three-dimensional T2 Rapid Acquisition Relaxation Enhancement (RARE sequence and quantified the volume of the hippocampus and one of its thinnest layers, the stratum granulare of the dentate gyrus. Additionally, we tested passive staining by gadolinium with the aim of decreasing the acquisition time and increasing image contrast. Using appropriated settings, six discrete layers were differentiated within the hippocampus in rats. In the hippocampus proper or Ammon's Horn (AH: the stratum oriens, the stratum pyramidale of, the stratum radiatum, and the stratum lacunosum moleculare of the CA1 were differentiated. In the dentate gyrus: the stratum moleculare and the stratum granulare layer were seen distinctly. Passive staining of one brain with gadolinium decreased the acquisition time by four and improved the differentiation between the layers. A conventional sequence optimized on a 7T MRI with a standard receiver surface coil will allow us to study structural layers (signal and volume of hippocampus in various rat models of neuropathology (anxiety, epilepsia, neurodegeneration.

Experimental and clinical evaluation of acromioclavicular joint structures with new scan orientations in MRI

International Nuclear Information System (INIS)

Schaefer, Fritz K.; Schaefer, Philipp J.; Brossmann, Joachim; Hilgert, Ralf Erik; Heller, Martin; Jahnke, Thomas

2006-01-01

The objective of the study was to evaluate MRI for visualization of acromioclavicular (ac) joint structures in cadaveric shoulders, asymptomatic volunteers and symptomatic patients with trauma of the ac-joint. Three cadaveric shoulders were examined to find adequate planes and sequences for MRI. Afterwards, MR images were correlated to corresponding anatomical sections. Six asymptomatic volunteers and 13 patients were scanned in a 1.5 T Magnetom Vision with three sequences in the following planes: (1) parallel to the clavicle; (2) orthogonal to the ac joint, each time a fat-suppressed proton density-weighted + T2-sequence (TR/TE 4,000/15 ms) was performed; (3) parallel to the clavicle, T1-SE (TR/TE 817/20 ms). The parameters were: slice thickness 3 mm, field-of-view 180 mm, matrix 210 x 256 pixels. Standard of reference in the patients was clinical examination and conventional X-rays. Classification was by Rockwood grades I-VI. MRI allowed excellent visualization and diagnoses of ac-joint structures in volunteers and patients (n=6 normal, n=1 Rockwood I, n=5 Rockwood II, n=3 Rockwood III, n=4 Rockwood V). On MRI, in one lesion type II and III each, a lower lesion type was suspected clinically and by X-ray. In one patient additional information by MRI led to surgery. MRI allows excellent anatomical display of ac-joint structures and can give clinically relevant information on type and extension of ac-joint trauma, which may influence therapy. (orig.)

Experimental and clinical evaluation of acromioclavicular joint structures with new scan orientations in MRI

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Schaefer, Fritz K.; Schaefer, Philipp J.; Brossmann, Joachim; Hilgert, Ralf Erik; Heller, Martin; Jahnke, Thomas [University Hospital of Schleswig-Holstein Campus Kiel, Department of Diagnostic Radiology, Kiel (Germany)

2006-07-15

The objective of the study was to evaluate MRI for visualization of acromioclavicular (ac) joint structures in cadaveric shoulders, asymptomatic volunteers and symptomatic patients with trauma of the ac-joint. Three cadaveric shoulders were examined to find adequate planes and sequences for MRI. Afterwards, MR images were correlated to corresponding anatomical sections. Six asymptomatic volunteers and 13 patients were scanned in a 1.5 T Magnetom Vision with three sequences in the following planes: (1) parallel to the clavicle; (2) orthogonal to the ac joint, each time a fat-suppressed proton density-weighted + T2-sequence (TR/TE 4,000/15 ms) was performed; (3) parallel to the clavicle, T1-SE (TR/TE 817/20 ms). The parameters were: slice thickness 3 mm, field-of-view 180 mm, matrix 210 x 256 pixels. Standard of reference in the patients was clinical examination and conventional X-rays. Classification was by Rockwood grades I-VI. MRI allowed excellent visualization and diagnoses of ac-joint structures in volunteers and patients (n=6 normal, n=1 Rockwood I, n=5 Rockwood II, n=3 Rockwood III, n=4 Rockwood V). On MRI, in one lesion type II and III each, a lower lesion type was suspected clinically and by X-ray. In one patient additional information by MRI led to surgery. MRI allows excellent anatomical display of ac-joint structures and can give clinically relevant information on type and extension of ac-joint trauma, which may influence therapy. (orig.)

Differentiating between bipolar and unipolar depression in functional and structural MRI studies.

Science.gov (United States)

Han, Kyu-Man; De Berardis, Domenico; Fornaro, Michele; Kim, Yong-Ku

2018-03-28

Distinguishing depression in bipolar disorder (BD) from unipolar depression (UD) solely based on clinical clues is difficult, which has led to the exploration of promising neural markers in neuroimaging measures for discriminating between BD depression and UD. In this article, we review structural and functional magnetic resonance imaging (MRI) studies that directly compare UD and BD depression based on neuroimaging modalities including functional MRI studies on regional brain activation or functional connectivity, structural MRI on gray or white matter morphology, and pattern classification analyses using a machine learning approach. Numerous studies have reported distinct functional and structural alterations in emotion- or reward-processing neural circuits between BD depression and UD. Different activation patterns in neural networks including the amygdala, anterior cingulate cortex (ACC), prefrontal cortex (PFC), and striatum during emotion-, reward-, or cognition-related tasks have been reported between BD and UD. A stronger functional connectivity pattern in BD was pronounced in default mode and in frontoparietal networks and brain regions including the PFC, ACC, parietal and temporal regions, and thalamus compared to UD. Gray matter volume differences in the ACC, hippocampus, amygdala, and dorsolateral prefrontal cortex (DLPFC) have been reported between BD and UD, along with a thinner DLPFC in BD compared to UD. BD showed reduced integrity in the anterior part of the corpus callosum and posterior cingulum compared to UD. Several studies performed pattern classification analysis using structural and functional MRI data to distinguish between UD and BD depression using a supervised machine learning approach, which yielded a moderate level of accuracy in classification. Copyright © 2018 Elsevier Inc. All rights reserved.

Streamlining the Process of 3D Printing a Brain From a Structural MRI

Directory of Open Access Journals (Sweden)

Daniel Peterson

2017-05-01

Full Text Available Currently, the process of obtaining a 3D model from a structural MRI requires specialized knowlege and skills. This is not due to the fundamental difficulty and complexity of the process, but is a result of the fact that the neccessary tools were developed for and by neuroimaging researchers. This project describes a publically available utility implemented as a Docker image that takes a structural MRI as input, and gives files for 3D printing as output, along with a rendered image of the surface.

Synthesis, structural characterization and in vitro testing of dysprosium containing silica particles as potential MRI contrast enhancing agents

International Nuclear Information System (INIS)

Chiriac, L.B.; Trandafir, D.L.; Turcu, R.V.F.; Todea, M.; Simon, S.

2016-01-01

Highlights: • Dysprosium containing silica microparticles obtained by freeze and spray drying. • Higher structural units interconnection achieved in freeze vs. spray dried samples. • Dy occurance on the outermost layer of the microparticles evidenced by XPS. • Enhanced MRI contrast observed for freeze dried samples with 5% mol Dy_2O_3. - Abstract: The work is focused on synthesis and structural characterization of novel dysprosium-doped silica particles which could be considered as MRI contrast agents. Sol-gel derived silica rich particles obtained via freeze-drying and spray-drying processing methods were structurally characterized by XRD, "2"9Si MAS-NMR and XPS methods. The occurrence of dysprosium on the outermost layer of dysprosium containing silica particles was investigated by XPS analysis. The MRI contrast agent characteristics have been tested using RARE-T_1 and RARE-T_2 protocols. The contrast of MRI images delivered by the investigated samples was correlated with their local structure. Dysprosium disposal on microparticles with surface structure characterised by decreased connectivity of the silicate network units favours dark T_2-weighted MRI contrast properties.

Functional and structural abnormalities associated with empathy in patients with schizophrenia: An fMRI and VBM study

OpenAIRE

Singh, Sadhana; Modi, Shilpi; Goyal, Satnam; Kaur, Prabhjot; Singh, Namita; Bhatia, Triptish; Deshpande, Smita N; Khushu, Subash

2015-01-01

Empathy deficit is a core feature of schizophrenia which may lead to social dysfunction. The present study was carried out to investigate functional and structural abnormalities associated with empathy in patients with schizophrenia using functional magnetic resonance imaging (fMRI) and voxel-based morphometry (VBM). A sample of 14 schizophrenia patients and 14 healthy control subjects matched for age, sex and education were examined with structural high-resolution T1-weighted MRI; fMRI image...

Association between MRI structural features and cognitive measures in pediatric multiple sclerosis

Science.gov (United States)

Amoroso, N.; Bellotti, R.; Fanizzi, A.; Lombardi, A.; Monaco, A.; Liguori, M.; Margari, L.; Simone, M.; Viterbo, R. G.; Tangaro, S.

2017-09-01

Multiple sclerosis (MS) is an inflammatory and demyelinating disease associated with neurodegenerative processes that lead to brain structural changes. The disease affects mostly young adults, but 3-5% of cases has a pediatric onset (POMS). Magnetic Resonance Imaging (MRI) is generally used for diagnosis and follow-up in MS patients, however the most common MRI measures (e.g. new or enlarging T2-weighted lesions, T1-weighted gadolinium- enhancing lesions) have often failed as surrogate markers of MS disability and progression. MS is clinically heterogenous with symptoms that can include both physical changes (such as visual loss or walking difficulties) and cognitive impairment. 30-50% of POMS experience prominent cognitive dysfunction. In order to investigate the association between cognitive measures and brain morphometry, in this work we present a fully automated pipeline for processing and analyzing MRI brain scans. Relevant anatomical structures are segmented with FreeSurfer; besides, statistical features are computed. Thus, we describe the data referred to 12 patients with early POMS (mean age at MRI: 15.5 +/- 2.7 years) with a set of 181 structural features. The major cognitive abilities measured are verbal and visuo-spatial learning, expressive language and complex attention. Data was collected at the Department of Basic Sciences, Neurosciences and Sense Organs, University of Bari, and exploring different abilities like the verbal and visuo-spatial learning, expressive language and complex attention. Different regression models and parameter configurations are explored to assess the robustness of the results, in particular Generalized Linear Models, Bayes Regression, Random Forests, Support Vector Regression and Artificial Neural Networks are discussed.

Synthesis, structural characterization and in vitro testing of dysprosium containing silica particles as potential MRI contrast enhancing agents

Energy Technology Data Exchange (ETDEWEB)

Chiriac, L.B.; Trandafir, D.L. [Faculty of Physics & National Magnetic Resonance Center, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Interdisciplinary Research Institute on Bio-Nano-Sciences & Faculty of Physics, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Turcu, R.V.F. [Faculty of Physics & National Magnetic Resonance Center, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Todea, M. [Interdisciplinary Research Institute on Bio-Nano-Sciences & Faculty of Physics, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Simon, S., E-mail: simons@phys.ubbcluj.ro [Faculty of Physics & National Magnetic Resonance Center, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Interdisciplinary Research Institute on Bio-Nano-Sciences & Faculty of Physics, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania)

2016-11-01

Highlights: • Dysprosium containing silica microparticles obtained by freeze and spray drying. • Higher structural units interconnection achieved in freeze vs. spray dried samples. • Dy occurance on the outermost layer of the microparticles evidenced by XPS. • Enhanced MRI contrast observed for freeze dried samples with 5% mol Dy{sub 2}O{sub 3}. - Abstract: The work is focused on synthesis and structural characterization of novel dysprosium-doped silica particles which could be considered as MRI contrast agents. Sol-gel derived silica rich particles obtained via freeze-drying and spray-drying processing methods were structurally characterized by XRD, {sup 29}Si MAS-NMR and XPS methods. The occurrence of dysprosium on the outermost layer of dysprosium containing silica particles was investigated by XPS analysis. The MRI contrast agent characteristics have been tested using RARE-T{sub 1} and RARE-T{sub 2} protocols. The contrast of MRI images delivered by the investigated samples was correlated with their local structure. Dysprosium disposal on microparticles with surface structure characterised by decreased connectivity of the silicate network units favours dark T{sub 2}-weighted MRI contrast properties.

Comparison between hybrid feedforward-feedback, feedforward, and feedback structures for active noise control of fMRI noise.

Science.gov (United States)

Reddy, Rajiv M; Panahi, Issa M S

2008-01-01

The performance of FIR feedforward, IIR feedforward, FIR feedback, hybrid FIR feedforward--FIR feedback, and hybrid IIR feedforward - FIR feedback structures for active noise control (ANC) are compared for an fMRI noise application. The filtered-input normalized least squares (FxNLMS) algorithm is used to update the coefficients of the adaptive filters in all these structures. Realistic primary and secondary paths of an fMRI bore are used by estimating them on a half cylindrical acrylic bore of 0.76 m (D)x1.52 m (L). Detailed results of the performance of the ANC system are presented in the paper for each of these structures. We find that the IIR feedforward structure produces most of the performance improvement in the hybrid IIR feedforward - FIR feedback structure and adding the feedback structure becomes almost redundant in the case of fMRI noise.

Automatic analysis of trabecular bone structure from knee MRI

DEFF Research Database (Denmark)

Marques, Joselene; Granlund, Rabia; Lillholm, Martin

2012-01-01

We investigated the feasibility of quantifying osteoarthritis (OA) by analysis of the trabecular bone structure in low-field knee MRI. Generic texture features were extracted from the images and subsequently selected by sequential floating forward selection (SFFS), following a fully automatic......, uncommitted machine-learning based framework. Six different classifiers were evaluated in cross-validation schemes and the results showed that the presence of OA can be quantified by a bone structure marker. The performance of the developed marker reached a generalization area-under-the-ROC (AUC) of 0...

Systematic evaluation of MRI findings in different stages of treatment of cervical cancer: Potential of MRI on delineation of target, pathoanatomic structures, and organs at risk

International Nuclear Information System (INIS)

Dimopoulos, Johannes; Schard, Gerdi; Berger, Daniel; Lang, Stefan; Goldner, Gregor; Helbich, Thomas; Poetter, Richard

2006-01-01

Purpose: To compare magnetic resonance imaging (MRI) findings at different stages of cervix cancer treatment and to define the potential of MRI to delineate the gross tumor volume (GTV), clinical target volume (CTV), pathoanatomic structures, and organs at risk (OAR) in brachytherapy. Methods and Materials: Forty-nine patients underwent MRI at diagnosis and at brachytherapy. The ability to discriminate anatomic structures on MRI was assessed (quality factor: 0 = inability to discriminate; 1 = fair discrimination; 2 = good discrimination; 3 = excellent discrimination). The overall ability to visualize (percentage of patients with quality factors greater than 0) and the overall discrimination quality score (mean quality factors of all patients) were estimated for the applicator, GTV at diagnosis (GTV D ), GTV at brachytherapy (GTV BT )/'gray zones,' cervix rim/uterine corpus, OAR, vaginal wall, and parametria. Results: The overall ability to visualize the applicator on MRI at brachytherapy was 100%; for the GTV BT /'gray zones,' cervix rim/uterine corpus, OAR, and vaginal wall, visualization was 98% (overall discrimination quality factors: 1.2, 2.9, 2.1, 1.9, 1.7, and 2.6). Three of 4 borders of parametrial space were defined in more than 98% (discrimination quality factors: 2.9, 2.1, and 1.2). Conclusion: Magnetic resonance imaging provides appropriate information for definition of the applicator, GTV, CTV, pathoanatomic structures, and OAR that enables precise delineation for cervix cancer brachytherapy

Verbal Memory Decline following DBS for Parkinson's Disease: Structural Volumetric MRI Relationships.

Science.gov (United States)

Geevarghese, Ruben; Lumsden, Daniel E; Costello, Angela; Hulse, Natasha; Ayis, Salma; Samuel, Michael; Ashkan, Keyoumars

2016-01-01

Parkinson's disease is a chronic degenerative movement disorder. The mainstay of treatment is medical. In certain patients Deep Brain Stimulation (DBS) may be offered. However, DBS has been associated with post-operative neuropsychology changes, especially in verbal memory. Firstly, to determine if pre-surgical thalamic and hippocampal volumes were related to verbal memory changes following DBS. Secondly, to determine if clinical factors such as age, duration of symptoms or motor severity (UPDRS Part III score) were related to verbal memory changes. A consecutive group of 40 patients undergoing bilateral Subthalamic Nucleus (STN)-DBS for PD were selected. Brain MRI data was acquired, pre-processed and structural volumetric data was extracted using FSL. Verbal memory test scores for pre- and post-STN-DBS surgery were recorded. Linear regression was used to investigate the relationship between score change and structural volumetric data. A significant relationship was demonstrated between change in List Learning test score and thalamic (left, p = 0.02) and hippocampal (left, p = 0.02 and right p = 0.03) volumes. Duration of symptoms was also associated with List Learning score change (p = 0.02 to 0.03). Verbal memory score changes appear to have a relationship to pre-surgical MRI structural volumetric data. The findings of this study provide a basis for further research into the use of pre-surgical MRI to counsel PD patients regarding post-surgical verbal memory changes.

Novel frontiers in ultra-structural and molecular MRI of the brain.

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Duyn, Jeff H; Koretsky, Alan P

2011-08-01

Recent developments in the MRI of the brain continue to expand its use in basic and clinical neuroscience. This review highlights some areas of recent progress. Higher magnetic field strengths and improved signal detectors have allowed improved visualization of the various properties of the brain, facilitating the anatomical definition of function-specific areas and their connections. For example, by sensitizing the MRI signal to the magnetic susceptibility of tissue, it is starting to become possible to reveal the laminar structure of the cortex and identify millimeter-scale fiber bundles. Using exogenous contrast agents, and innovative ways to manipulate contrast, it is becoming possible to highlight specific fiber tracts and cell populations. These techniques are bringing us closer to understanding the evolutionary blueprint of the brain, improving the detection and characterization of disease, and help to guide treatment. Recent MRI techniques are leading to more detailed and more specific contrast in the study of the brain.

Structural changes in brain substance in children with epilepsy (MRI findings)

International Nuclear Information System (INIS)

Kaduk, Je.G.

2000-01-01

The structural changes in the brain substance and the parameters of liquor-containing spaces in children with epilepsy are studied. Structural morphological changes in the brain were found in 30, 7 % of cases. In 27, 7 % MRI findings did not differ from the control. The number of porencephalic changes in the both groups was similar (4, 2 - 4, 3 % of cases). Hypotrophy of cortical and subcortical structures, dysgenesis of the colossal body were observed in the group of local epilepsy. Typodense changes of pervantricular structures were more frequent in the patients will local disease. Hypodense changes of the periventricular structures were more frequent in the patients with local disturbances

Exploring structure and function of sensory cortex with 7T MRI.

Science.gov (United States)

Schluppeck, Denis; Sanchez-Panchuelo, Rosa-Maria; Francis, Susan T

2018-01-01

In this paper, we present an overview of 7T magnetic resonance imaging (MRI) studies of the detailed function and anatomy of sensory areas of the human brain. We discuss the motivation for the studies, with particular emphasis on increasing the spatial resolution of functional MRI (fMRI) using reduced field-of-view (FOV) data acquisitions. MRI at ultra-high-field (UHF) - defined here as 7T and above - has several advantages over lower field strengths. The intrinsic signal-to-noise ratio (SNR) of images is higher at UHF, and coupled with the increased blood-oxygen-level-dependent (BOLD) signal change, this results in increased BOLD contrast-to-noise ratio (CNR), which can be exploited to improve spatial resolution or detect weaker signals. Additionally, the BOLD signal from the intra-vascular (IV) compartment is relatively diminished compared to lower field strengths. Together, these properties make 7T functional MRI an attractive proposition for high spatial specificity measures. But with the advantages come some challenges. For example, increased vulnerability to susceptibility-induced geometric distortions and signal loss in EPI acquisitions tend to be much larger. Some of these technical issues can be addressed with currently available tools and will be discussed. We highlight the key methodological considerations for high resolution functional and structural imaging at 7 T. We then present recent data using the high spatial resolution available at UHF in studies of the visual and somatosensory cortex to highlight promising developments in this area. Copyright © 2017 Elsevier Inc. All rights reserved.

Skin age testing criteria: characterization of human skin structures by 500 MHz MRI multiple contrast and image processing

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Sharma, Rakesh, E-mail: rs05h@fsu.ed [Departments of Chemical Engineering and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, FL 32310 (United States)

2010-07-21

Ex vivo magnetic resonance microimaging (MRM) image characteristics are reported in human skin samples in different age groups. Human excised skin samples were imaged using a custom coil placed inside a 500 MHz NMR imager for high-resolution microimaging. Skin MRI images were processed for characterization of different skin structures. Contiguous cross-sectional T1-weighted 3D spin echo MRI, T2-weighted 3D spin echo MRI and proton density images were compared with skin histopathology and NMR peaks. In all skin specimens, epidermis and dermis thickening and hair follicle size were measured using MRM. Optimized parameters TE and TR and multicontrast enhancement generated better MRI visibility of different skin components. Within high MR signal regions near to the custom coil, MRI images with short echo time were comparable with digitized histological sections for skin structures of the epidermis, dermis and hair follicles in 6 (67%) of the nine specimens. Skin % tissue composition, measurement of the epidermis, dermis, sebaceous gland and hair follicle size, and skin NMR peaks were signatures of skin type. The image processing determined the dimensionality of skin tissue components and skin typing. The ex vivo MRI images and histopathology of the skin may be used to measure the skin structure and skin NMR peaks with image processing may be a tool for determining skin typing and skin composition.

Skin age testing criteria: characterization of human skin structures by 500 MHz MRI multiple contrast and image processing

International Nuclear Information System (INIS)

Sharma, Rakesh

2010-01-01

Ex vivo magnetic resonance microimaging (MRM) image characteristics are reported in human skin samples in different age groups. Human excised skin samples were imaged using a custom coil placed inside a 500 MHz NMR imager for high-resolution microimaging. Skin MRI images were processed for characterization of different skin structures. Contiguous cross-sectional T1-weighted 3D spin echo MRI, T2-weighted 3D spin echo MRI and proton density images were compared with skin histopathology and NMR peaks. In all skin specimens, epidermis and dermis thickening and hair follicle size were measured using MRM. Optimized parameters TE and TR and multicontrast enhancement generated better MRI visibility of different skin components. Within high MR signal regions near to the custom coil, MRI images with short echo time were comparable with digitized histological sections for skin structures of the epidermis, dermis and hair follicles in 6 (67%) of the nine specimens. Skin % tissue composition, measurement of the epidermis, dermis, sebaceous gland and hair follicle size, and skin NMR peaks were signatures of skin type. The image processing determined the dimensionality of skin tissue components and skin typing. The ex vivo MRI images and histopathology of the skin may be used to measure the skin structure and skin NMR peaks with image processing may be a tool for determining skin typing and skin composition.

Mapping the order and pattern of brain structural MRI changes using change-point analysis in premanifest Huntington's disease.

Science.gov (United States)

Wu, Dan; Faria, Andreia V; Younes, Laurent; Mori, Susumu; Brown, Timothy; Johnson, Hans; Paulsen, Jane S; Ross, Christopher A; Miller, Michael I

2017-10-01

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder that progressively affects motor, cognitive, and emotional functions. Structural MRI studies have demonstrated brain atrophy beginning many years prior to clinical onset ("premanifest" period), but the order and pattern of brain structural changes have not been fully characterized. In this study, we investigated brain regional volumes and diffusion tensor imaging (DTI) measurements in premanifest HD, and we aim to determine (1) the extent of MRI changes in a large number of structures across the brain by atlas-based analysis, and (2) the initiation points of structural MRI changes in these brain regions. We adopted a novel multivariate linear regression model to detect the inflection points at which the MRI changes begin (namely, "change-points"), with respect to the CAG-age product (CAP, an indicator of extent of exposure to the effects of CAG repeat expansion). We used approximately 300 T1-weighted and DTI data from premanifest HD and control subjects in the PREDICT-HD study, with atlas-based whole brain segmentation and change-point analysis. The results indicated a distinct topology of structural MRI changes: the change-points of the volumetric measurements suggested a central-to-peripheral pattern of atrophy from the striatum to the deep white matter; and the change points of DTI measurements indicated the earliest changes in mean diffusivity in the deep white matter and posterior white matter. While interpretation needs to be cautious given the cross-sectional nature of the data, these findings suggest a spatial and temporal pattern of spread of structural changes within the HD brain. Hum Brain Mapp 38:5035-5050, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Structural Image Analysis of the Brain in Neuropsychology Using Magnetic Resonance Imaging (MRI) Techniques.

Science.gov (United States)

Bigler, Erin D

2015-09-01

Magnetic resonance imaging (MRI) of the brain provides exceptional image quality for visualization and neuroanatomical classification of brain structure. A variety of image analysis techniques provide both qualitative as well as quantitative methods to relate brain structure with neuropsychological outcome and are reviewed herein. Of particular importance are more automated methods that permit analysis of a broad spectrum of anatomical measures including volume, thickness and shape. The challenge for neuropsychology is which metric to use, for which disorder and the timing of when image analysis methods are applied to assess brain structure and pathology. A basic overview is provided as to the anatomical and pathoanatomical relations of different MRI sequences in assessing normal and abnormal findings. Some interpretive guidelines are offered including factors related to similarity and symmetry of typical brain development along with size-normalcy features of brain anatomy related to function. The review concludes with a detailed example of various quantitative techniques applied to analyzing brain structure for neuropsychological outcome studies in traumatic brain injury.

Neuronal pathology in deep grey matter structures: a multimodal imaging analysis combining PET and MRI

Energy Technology Data Exchange (ETDEWEB)

Bosque-Freeman, L.; Leroy, C.; Galanaud, D.; Sureau, F.; Assouad, R.; Tourbah, A.; Papeix, C.; Comtat, C.; Trebossen, R.; Lubetzki, C.; Delforge, J.; Bottlaender, M.; Stankoff, B. [Serv. Hosp. Frederic Joliot, Orsay (France)

2009-07-01

Objective: To assess neuronal damage in deep gray matter structures by positron emission tomography (PET) using [{sup 11}C]-flumazenil (FMZ), a specific central benzodiazepine receptor antagonist, and [{sup 18}F]-fluorodeoxyglucose (FDG), which reflects neuronal metabolism. To compare results obtained by PET and those with multimodal magnetic resonance imaging (MRI). Background: It is now accepted that neuronal injury plays a crucial role in the occurrence and progression of neurological disability in multiple sclerosis (MS). To date, available MRI techniques do not specifically assess neuronal damage, but early abnormalities, such as iron deposition or atrophy, have been described in deep gray matter structures. Whether those MRI modifications correspond to neuronal damage remains to be further investigated. Materials and methods: Nine healthy volunteers were compared to 10 progressive and 9 relapsing remitting (RR) MS patients. Each subject performed two PET examinations with [{sup 11}C]-FMZ and [{sup 18}F]-FDG, on a high resolution research tomograph dedicated to brain imaging (Siemens Medical Solution, spatial resolution of 2.5 mm). Deep gray matter regions were manually segmented on T1-weighted MR images with the mutual information algorithm (www.brainvisa.info), and co-registered with PET images. A multimodal MRI including T1 pre and post gadolinium, T2-proton density sequences, magnetization transfer, diffusion tensor, and protonic spectroscopy was also performed for each subject. Results: On PET with [{sup 11}C]-FMZ, there was a pronounced decrease in receptor density for RR patients in all deep gray matter structures investigated, whereas the density was unchanged or even increased in the same regions for progressive patients. Whether the different patterns between RR and progressive patients reflect distinct pathogenic mechanisms is currently investigated by comparing PET and multimodal MRI results. Conclusion: Combination of PET and multimodal MR imaging

Descriptions of spinal MRI lesions and definition of a positive MRI of the spine in axial spondyloarthritis

DEFF Research Database (Denmark)

Hermann, Kay-Geert A; Baraliakos, Xenofon; van der Heijde, Désirée M F M

2012-01-01

The aim of this study was to define characteristic MRI findings in the spine of patients with axial spondyloarthritis (SpA) and provide a definition of a positive spinal MRI for inflammation and structural changes.......The aim of this study was to define characteristic MRI findings in the spine of patients with axial spondyloarthritis (SpA) and provide a definition of a positive spinal MRI for inflammation and structural changes....

A High-resolution Atlas and Statistical Model of the Vocal Tract from Structural MRI.

Science.gov (United States)

Woo, Jonghye; Lee, Junghoon; Murano, Emi Z; Xing, Fangxu; Al-Talib, Meena; Stone, Maureen; Prince, Jerry L

Magnetic resonance imaging (MRI) is an essential tool in the study of muscle anatomy and functional activity in the tongue. Objective assessment of similarities and differences in tongue structure and function has been performed using unnormalized data, but this is biased by the differences in size, shape, and orientation of the structures. To remedy this, we propose a methodology to build a 3D vocal tract atlas based on structural MRI volumes from twenty normal subjects. We first constructed high-resolution volumes from three orthogonal stacks. We then removed extraneous data so that all 3D volumes contained the same anatomy. We used an unbiased diffeomorphic groupwise registration using a cross-correlation similarity metric. Principal component analysis was applied to the deformation fields to create a statistical model from the atlas. Various evaluations and applications were carried out to show the behaviour and utility of the atlas.

Altered Structural and Functional Connectivity of Juvenile Myoclonic Epilepsy: An fMRI Study

Directory of Open Access Journals (Sweden)

Chengqing Zhong

2018-01-01

Full Text Available The aim of this study was to investigate the structural and functional connectivity (FC of juvenile myoclonic epilepsy (JME using resting state functional magnetic resonance imaging (rs-fMRI. High-resolution T1-weighted magnetic resonance imaging (MRI and rs-fMRI data were collected in 25 patients with JME and in 24 control subjects. A FC analysis was subsequently performed, with seeding at the regions that demonstrated between-group differences in gray matter volume (GMV. Then, the observed structural and FCs were associated with the clinical manifestations. The decreased GMV regions were found in the bilateral anterior cerebellum, the right orbital superior frontal gyrus, the left middle temporal gyrus, the left putamen, the right hippocampus, the bilateral caudate, and the right thalamus. The changed FCs were mainly observed in the motor-related areas and the cognitive-related areas. The significant findings of this study revealed an important role for the cerebellum in motor control and cognitive regulation in JME patients, which also have an effect on the activity of the occipital lobe. In addition, the changed FCs were related to the clinical features of JME patients. The current observations may contribute to the understanding of the pathogenesis of JME.

Functional and structural abnormalities associated with empathy in patients with schizophrenia: An fMRI and VBM study.

Science.gov (United States)

Singh, Sadhana; Modi, Shilpi; Goyal, Satnam; Kaur, Prabhjot; Singh, Namita; Bhatia, Triptish; Deshpande, Smita N; Khushu, Subash

2015-06-01

Empathy deficit is a core feature of schizophrenia which may lead to social dysfunction. The present study was carried out to investigate functional and structural abnormalities associated with empathy in patients with schizophrenia using functional magnetic resonance imaging (fMRI) and voxel-based morphometry (VBM). A sample of 14 schizophrenia patients and 14 healthy control subjects matched for age, sex and education were examined with structural highresolution T1-weighted MRI; fMRI images were obtained during empathy task in the same session. The analysis was carried out using SPM8 software. On behavioural assessment, schizophrenic patients (83.00+-29.04) showed less scores for sadness compared to healthy controls (128.70+-22.26) (p less than 0.001). fMRI results also showed reduced clusters of activation in the bilateral fusiform gyrus, left lingual gyrus, left middle and inferior occipital gyrus in schizophrenic subjects as compared to controls during empathy task. In the same brain areas, VBM results also showed reduced grey and white matter volumes. The present study provides an evidence for an association between structural alterations and disturbed functional brain activation during empathy task in persons affected with schizophrenia. These findings suggest a biological basis for social cognition deficits in schizophrenics.

Essential items for structured reporting of rectal cancer MRI: 2016 consensus recommendation from the Korean society of abdominal radiology

Energy Technology Data Exchange (ETDEWEB)

NONE

2017-01-15

High-resolution rectal MRI plays a crucial role in evaluating rectal cancer by providing multiple prognostic findings and imaging features that guide proper patient management. Quality reporting is critical for accurate effective communication of the information among multiple disciplines, for which a systematic structured approach is beneficial. Existing guides on reporting of rectal MRI are divergent on some issues, largely reflecting the differences in overall management of rectal cancer patients between the United States and Europe. The Korean Society of Abdominal Radiology (KSAR) study group for rectal cancer has developed an expert consensus recommendation regarding essential items for structured reporting of rectal cancer MRI using a modified Delphi method. This recommendation aims at presenting an up-to-date, evidence-based, practical, structured reporting template that can be readily adopted in daily clinical practice. In addition, a thorough explanation of the clinical and scientific rationale underlying the reporting items and their formats is provided. This KSAR recommendation may serve as a useful tool to help achieve more standardized optimal care for rectal cancer patients using rectal MRI.

Essential items for structured reporting of rectal cancer MRI: 2016 consensus recommendation from the Korean society of abdominal radiology

International Nuclear Information System (INIS)

2017-01-01

High-resolution rectal MRI plays a crucial role in evaluating rectal cancer by providing multiple prognostic findings and imaging features that guide proper patient management. Quality reporting is critical for accurate effective communication of the information among multiple disciplines, for which a systematic structured approach is beneficial. Existing guides on reporting of rectal MRI are divergent on some issues, largely reflecting the differences in overall management of rectal cancer patients between the United States and Europe. The Korean Society of Abdominal Radiology (KSAR) study group for rectal cancer has developed an expert consensus recommendation regarding essential items for structured reporting of rectal cancer MRI using a modified Delphi method. This recommendation aims at presenting an up-to-date, evidence-based, practical, structured reporting template that can be readily adopted in daily clinical practice. In addition, a thorough explanation of the clinical and scientific rationale underlying the reporting items and their formats is provided. This KSAR recommendation may serve as a useful tool to help achieve more standardized optimal care for rectal cancer patients using rectal MRI

Unraveling the multiscale structural organization and connectivity of the human brain: the role of diffusion MRI

Directory of Open Access Journals (Sweden)

Matteo eBastiani

2015-06-01

Full Text Available The structural architecture and the anatomical connectivity of the human brain show different organizational principles at distinct spatial scales. Histological staining and light microscopy techniques have been widely used in classical neuroanatomical studies to unravel brain organization. Using such techniques is a laborious task performed on 2-dimensional histological sections by skilled anatomists possibly aided by semi-automated algorithms. With the recent advent of modern magnetic resonance imaging (MRI contrast mechanisms, cortical layers and columns can now be reliably identified and their structural properties quantified post mortem. These developments are allowing the investigation of neuroanatomical features of the brain at a spatial resolution that could be interfaced with that of histology. Diffusion MRI and tractography techniques, in particular, have been used to probe the architecture of both white and gray matter in three dimensions. Combined with mathematical network analysis, these techniques are increasingly influential in the investigation of the macro-, meso- and microscopic organization of brain connectivity and anatomy, both in vivo and ex vivo. Diffusion MRI-based techniques in combination with histology approaches can therefore support the endeavor of creating multimodal atlases that take into account the different spatial scales or levels on which the brain is organized. The aim of this review is to illustrate and discuss the structural architecture and the anatomical connectivity of the human brain at different spatial scales and how recently developed diffusion MRI techniques can help investigate these.

MRI to assess renal structure and function.

Science.gov (United States)

Artunc, Ferruh; Rossi, Cristina; Boss, Andreas

2011-11-01

In addition to excellent anatomical depiction, MRI techniques have expanded to study functional aspects of renal physiology, such as renal perfusion, glomerular filtration rate (GFR) or tissue oxygenation. This review will focus on current developments with an emphasis on clinical applicability. The method of GFR determination is largely heterogeneous and still has weaknesses. However, the technique of employing liver disappearance curves has been shown to be accurate in healthy persons and patients with chronic kidney disease. In potential kidney donors, complete evaluation of kidney anatomy and function can be accomplished in a single-stop investigation. Techniques without contrast media can be utilized to measure renal tissue oxygenation (blood oxygen level-dependent MRI) or perfusion (arterial spin labeling) and could aid in the diagnosis and treatment of ischemic renal diseases, such as renal artery stenosis. Diffusion imaging techniques may provide information on spatially restricted water diffusion and tumor cellularity. Functional MRI opens new horizons in studying renal physiology and pathophysiology in vivo. Although extensively utilized in research, labor-intensive postprocessing and lack of standardization currently limit the clinical applicability of functional MRI. Further studies are necessary to evaluate the clinical value of functional magnetic resonance techniques for early discovery and characterization of kidney disease.

In vivo estimation of normal amygdala volume from structural MRI scans with anatomical-based segmentation.

Science.gov (United States)

Siozopoulos, Achilleas; Thomaidis, Vasilios; Prassopoulos, Panos; Fiska, Aliki

2018-02-01

Literature includes a number of studies using structural MRI (sMRI) to determine the volume of the amygdala, which is modified in various pathologic conditions. The reported values vary widely mainly because of different anatomical approaches to the complex. This study aims at estimating of the normal amygdala volume from sMRI scans using a recent anatomical definition described in a study based on post-mortem material. The amygdala volume has been calculated in 106 healthy subjects, using sMRI and anatomical-based segmentation. The resulting volumes have been analyzed for differences related to hemisphere, sex, and age. The mean amygdalar volume was estimated at 1.42 cm 3 . The mean right amygdala volume has been found larger than the left, but the difference for the raw values was within the limits of the method error. No intersexual differences or age-related alterations have been observed. The study provides a method for determining the boundaries of the amygdala in sMRI scans based on recent anatomical considerations and an estimation of the mean normal amygdala volume from a quite large number of scans for future use in comparative studies.

Degree of contribution (DoC) feature selection algorithm for structural brain MRI volumetric features in depression detection.

Science.gov (United States)

Kipli, Kuryati; Kouzani, Abbas Z

2015-07-01

Accurate detection of depression at an individual level using structural magnetic resonance imaging (sMRI) remains a challenge. Brain volumetric changes at a structural level appear to have importance in depression biomarkers studies. An automated algorithm is developed to select brain sMRI volumetric features for the detection of depression. A feature selection (FS) algorithm called degree of contribution (DoC) is developed for selection of sMRI volumetric features. This algorithm uses an ensemble approach to determine the degree of contribution in detection of major depressive disorder. The DoC is the score of feature importance used for feature ranking. The algorithm involves four stages: feature ranking, subset generation, subset evaluation, and DoC analysis. The performance of DoC is evaluated on the Duke University Multi-site Imaging Research in the Analysis of Depression sMRI dataset. The dataset consists of 115 brain sMRI scans of 88 healthy controls and 27 depressed subjects. Forty-four sMRI volumetric features are used in the evaluation. The DoC score of forty-four features was determined as the accuracy threshold (Acc_Thresh) was varied. The DoC performance was compared with that of four existing FS algorithms. At all defined Acc_Threshs, DoC outperformed the four examined FS algorithms for the average classification score and the maximum classification score. DoC has a good ability to generate reduced-size subsets of important features that could yield high classification accuracy. Based on the DoC score, the most discriminant volumetric features are those from the left-brain region.

Markov models for fMRI correlation structure: Is brain functional connectivity small world, or decomposable into networks?

Science.gov (United States)

Varoquaux, G; Gramfort, A; Poline, J B; Thirion, B

2012-01-01

Correlations in the signal observed via functional Magnetic Resonance Imaging (fMRI), are expected to reveal the interactions in the underlying neural populations through hemodynamic response. In particular, they highlight distributed set of mutually correlated regions that correspond to brain networks related to different cognitive functions. Yet graph-theoretical studies of neural connections give a different picture: that of a highly integrated system with small-world properties: local clustering but with short pathways across the complete structure. We examine the conditional independence properties of the fMRI signal, i.e. its Markov structure, to find realistic assumptions on the connectivity structure that are required to explain the observed functional connectivity. In particular we seek a decomposition of the Markov structure into segregated functional networks using decomposable graphs: a set of strongly-connected and partially overlapping cliques. We introduce a new method to efficiently extract such cliques on a large, strongly-connected graph. We compare methods learning different graph structures from functional connectivity by testing the goodness of fit of the model they learn on new data. We find that summarizing the structure as strongly-connected networks can give a good description only for very large and overlapping networks. These results highlight that Markov models are good tools to identify the structure of brain connectivity from fMRI signals, but for this purpose they must reflect the small-world properties of the underlying neural systems. Copyright © 2012 Elsevier Ltd. All rights reserved.

MRI of the Chest

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Full Text Available ... important to assess the health and function of these structures (heart, valves, great vessels, etc.). top of ... room. In addition to affecting the MRI images, these objects can become projectiles within the MRI scanner ...

MRI of the Chest

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Full Text Available ... other internal body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians ... computed tomography (CT) scans, MRI does not utilize ionizing radiation. Instead, radiofrequency pulses re-align hydrogen atoms ...

Studying neuroanatomy using MRI.

Science.gov (United States)

Lerch, Jason P; van der Kouwe, André J W; Raznahan, Armin; Paus, Tomáš; Johansen-Berg, Heidi; Miller, Karla L; Smith, Stephen M; Fischl, Bruce; Sotiropoulos, Stamatios N

2017-02-23

The study of neuroanatomy using imaging enables key insights into how our brains function, are shaped by genes and environment, and change with development, aging and disease. Developments in MRI acquisition, image processing and data modeling have been key to these advances. However, MRI provides an indirect measurement of the biological signals we aim to investigate. Thus, artifacts and key questions of correct interpretation can confound the readouts provided by anatomical MRI. In this review we provide an overview of the methods for measuring macro- and mesoscopic structure and for inferring microstructural properties; we also describe key artifacts and confounds that can lead to incorrect conclusions. Ultimately, we believe that, although methods need to improve and caution is required in interpretation, structural MRI continues to have great promise in furthering our understanding of how the brain works.

MRI of the Chest

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Full Text Available ... body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to evaluate various ... seen by other imaging modalities, such as chest x-ray or CT. A special form of MRI called ...

MRI of the Chest

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Full Text Available ... other internal body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to ... computed tomography (CT) scans, MRI does not utilize ionizing radiation. Instead, radiofrequency pulses re-align hydrogen atoms that ...

MRI of the Chest

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Full Text Available ... internal body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to evaluate various ... seen by other imaging modalities, such as chest x-ray or CT. A special form of MRI called ...

MRI of the lung

Energy Technology Data Exchange (ETDEWEB)

Kauczor, Hans-Ulrich (ed.) [University Clinic Heidelberg (Germany). Diagnostic and Interventional Radiology

2009-07-01

For a long time, only chest X-ray and CT were used to image lung structure, while nuclear medicine was employed to assess lung function. During the past decade significant developments have been achieved in the field of magnetic resonance imaging (MRI), enabling MRI to enter the clinical arena of chest imaging. Standard protocols can now be implemented on up-to-date scanners, allowing MRI to be used as a first-line imaging modality for various lung diseases, including cystic fibrosis, pulmonary hypertension and even lung cancer. The diagnostic benefits stem from the ability of MRI to visualize changes in lung structure while simultaneously imaging different aspects of lung function, such as perfusion, respiratory motion, ventilation and gas exchange. On this basis, novel quantitative surrogates for lung function can be obtained. This book provides a comprehensive overview of how to use MRI for imaging of lung disease. Special emphasis is placed on benign diseases requiring regular monitoring, given that it is patients with these diseases who derive the greatest benefit from the avoidance of ionizing radiation. (orig.)

Multiscale mining of fMRI data with hierarchical structured sparsity

International Nuclear Information System (INIS)

Jenatton, R.; Obozinski, G.; Bach, F.; Gramfort, Alexandre; Michel, Vincent; Thirion, Bertrand; Eger, Evelyne

2012-01-01

Reverse inference, or 'brain reading', is a recent paradigm for analyzing functional magnetic resonance imaging (fMRI) data, based on pattern recognition and statistical learning. By predicting some cognitive variables related to brain activation maps, this approach aims at decoding brain activity. Reverse inference takes into account the multivariate information between voxels and is currently the only way to assess how precisely some cognitive information is encoded by the activity of neural populations within the whole brain. However, it relies on a prediction function that is plagued by the curse of dimensionality, since there are far more features than samples, i.e., more voxels than fMRI volumes. To address this problem, different methods have been proposed, such as, among others, univariate feature selection, feature agglomeration and regularization techniques. In this paper, we consider a sparse hierarchical structured regularization. Specifically, the penalization we use is constructed from a tree that is obtained by spatially-constrained agglomerative clustering. This approach encodes the spatial structure of the data at different scales into the regularization, which makes the overall prediction procedure more robust to inter-subject variability. The regularization used induces the selection of spatially coherent predictive brain regions simultaneously at different scales. We test our algorithm on real data acquired to study the mental representation of objects, and we show that the proposed algorithm not only delineates meaningful brain regions but yields as well better prediction accuracy than reference methods. (authors)

MRI of the Chest

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Full Text Available ... computer to produce detailed pictures of organs, soft tissues, bone and virtually all other internal body structures. MRI ... cancer, heart and vascular disease, heart valve abnormalities, bone and other soft tissue abnormalities of the chest. MRI is also useful ...

Relationship between brain function (aEEG) and brain structure (MRI) and their predictive value for neurodevelopmental outcome of preterm infants.

Science.gov (United States)

Hüning, Britta; Storbeck, Tobias; Bruns, Nora; Dransfeld, Frauke; Hobrecht, Julia; Karpienski, Julia; Sirin, Selma; Schweiger, Bernd; Weiss, Christel; Felderhoff-Müser, Ursula; Müller, Hanna

2018-05-22

To improve the prediction of neurodevelopmental outcome in very preterm infants, this study used the combination of amplitude-integrated electroencephalography (aEEG) within the first 72 h of life and cranial magnetic resonance imaging (MRI) at term equivalent age. A single-center cohort of 38 infants born before 32 weeks of gestation was subjected to both investigations. Structural measurements were performed on MRI. Multiple regression analysis was used to identify independent factors including functional and structural brain measurements associated with outcome at a corrected age of 24 months. aEEG parameters significantly correlated with MRI measurements. Reduced deep gray matter volume was associated with low Burdjalov Score on day 3 (p neurodevelopmental outcome: intraventricular hemorrhage (p = 0.0060) and interhemispheric distance (p = 0.0052) for mental developmental index; Burdjalov Score day 1 (p = 0.0201) and interhemispheric distance (p = 0.0142) for psychomotor developmental index. Functional aEEG parameters were associated with altered brain maturation on MRI. The combination of aEEG and MRI contributes to the prediction of outcome at 24 months. What is Known: • Prematurity remains a risk factor for impaired neurodevelopment. • aEEG is used to measure brain activity in preterm infants and cranial MRI is performed to identify structural gray and white matter abnormalities with impact on neurodevelopmental outcome. What is New: • aEEG parameters observed within the first 72 h of life were associated with altered deep gray matter volumes, biparietal width, and transcerebellar diameter at term equivalent age. • The combination of aEEG and MRI contributes to the prediction of neurodevelopmental outcome at 2 years of corrected age in very preterm infants.

Mapping human whole-brain structural networks with diffusion MRI.

Directory of Open Access Journals (Sweden)

Patric Hagmann

Full Text Available Understanding the large-scale structural network formed by neurons is a major challenge in system neuroscience. A detailed connectivity map covering the entire brain would therefore be of great value. Based on diffusion MRI, we propose an efficient methodology to generate large, comprehensive and individual white matter connectional datasets of the living or dead, human or animal brain. This non-invasive tool enables us to study the basic and potentially complex network properties of the entire brain. For two human subjects we find that their individual brain networks have an exponential node degree distribution and that their global organization is in the form of a small world.

Structural brain alterations in primary open angle glaucoma: a 3T MRI study

OpenAIRE

Jieqiong Wang; Ting Li; Bernhard A. Sabel; Zhiqiang Chen; Hongwei Wen; Jianhong Li; Xiaobin Xie; Diya Yang; Weiwei Chen; Ningli Wang; Junfang Xian; Huiguang He

2016-01-01

Glaucoma is not only an eye disease but is also associated with degeneration of brain structures. We now investigated the pattern of visual and non-visual brain structural changes in 25 primary open angle glaucoma (POAG) patients and 25 age-gender-matched normal controls using T1-weighted imaging. MRI images were subjected to volume-based analysis (VBA) and surface-based analysis (SBA) in the whole brain as well as ROI-based analysis of the lateral geniculate nucleus (LGN), visual cortex (V1/...

Direct Patlak Reconstruction From Dynamic PET Data Using the Kernel Method With MRI Information Based on Structural Similarity.

Science.gov (United States)

Gong, Kuang; Cheng-Liao, Jinxiu; Wang, Guobao; Chen, Kevin T; Catana, Ciprian; Qi, Jinyi

2018-04-01

Positron emission tomography (PET) is a functional imaging modality widely used in oncology, cardiology, and neuroscience. It is highly sensitive, but suffers from relatively poor spatial resolution, as compared with anatomical imaging modalities, such as magnetic resonance imaging (MRI). With the recent development of combined PET/MR systems, we can improve the PET image quality by incorporating MR information into image reconstruction. Previously, kernel learning has been successfully embedded into static and dynamic PET image reconstruction using either PET temporal or MRI information. Here, we combine both PET temporal and MRI information adaptively to improve the quality of direct Patlak reconstruction. We examined different approaches to combine the PET and MRI information in kernel learning to address the issue of potential mismatches between MRI and PET signals. Computer simulations and hybrid real-patient data acquired on a simultaneous PET/MR scanner were used to evaluate the proposed methods. Results show that the method that combines PET temporal information and MRI spatial information adaptively based on the structure similarity index has the best performance in terms of noise reduction and resolution improvement.

MRI of the Chest

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Full Text Available ... structure of an organ and how it is working. MRI enables the discovery of abnormalities that might be obscured by bone with other imaging methods. The contrast material used in MRI exams is less likely to produce an allergic reaction than the ...

Function–structure connectivity in patients with severe brain injury as measured by MRI-DWI and FDG-PET

DEFF Research Database (Denmark)

Annen, J.; Heine, Lizette; Ziegler, E.

2016-01-01

A vast body of literature exists showing functional and structural dysfunction within the brains of patients with disorders of consciousness. However, the function (fluorodeoxyglucose FDG-PET metabolism)–structure (MRI-diffusion-weighted images; DWI) relationship and how it is affected in severel...

Multimodal structural MRI in the diagnosis of motor neuron diseases.

Science.gov (United States)

Ferraro, Pilar M; Agosta, Federica; Riva, Nilo; Copetti, Massimiliano; Spinelli, Edoardo Gioele; Falzone, Yuri; Sorarù, Gianni; Comi, Giancarlo; Chiò, Adriano; Filippi, Massimo

2017-01-01

This prospective study developed an MRI-based method for identification of individual motor neuron disease (MND) patients and test its accuracy at the individual patient level in an independent sample compared with mimic disorders. 123 patients with amyotrophic lateral sclerosis (ALS), 44 patients with predominantly upper motor neuron disease (PUMN), 20 patients with ALS-mimic disorders, and 78 healthy controls were studied. The diagnostic accuracy of precentral cortical thickness and diffusion tensor (DT) MRI metrics of corticospinal and motor callosal tracts were assessed in a training cohort and externally proved in a validation cohort using a random forest analysis. In the training set, precentral cortical thickness showed 0.86 and 0.89 accuracy in differentiating ALS and PUMN patients from controls, while DT MRI distinguished the two groups from controls with 0.78 and 0.92 accuracy. In ALS vs controls, the combination of cortical thickness and DT MRI metrics (combined model) improved the classification pattern (0.91 accuracy). In the validation cohort, the best accuracy was reached by DT MRI (0.87 and 0.95 accuracy in ALS and PUMN vs mimic disorders). The combined model distinguished ALS and PUMN patients from mimic syndromes with 0.87 and 0.94 accuracy. A multimodal MRI approach that incorporates motor cortical and white matter alterations yields statistically significant improvement in accuracy over using each modality separately in the individual MND patient classification. DT MRI represents the most powerful tool to distinguish MND from mimic disorders.

Multimodal structural MRI in the diagnosis of motor neuron diseases

Directory of Open Access Journals (Sweden)

Pilar M. Ferraro

2017-01-01

Full Text Available This prospective study developed an MRI-based method for identification of individual motor neuron disease (MND patients and test its accuracy at the individual patient level in an independent sample compared with mimic disorders. 123 patients with amyotrophic lateral sclerosis (ALS, 44 patients with predominantly upper motor neuron disease (PUMN, 20 patients with ALS-mimic disorders, and 78 healthy controls were studied. The diagnostic accuracy of precentral cortical thickness and diffusion tensor (DT MRI metrics of corticospinal and motor callosal tracts were assessed in a training cohort and externally proved in a validation cohort using a random forest analysis. In the training set, precentral cortical thickness showed 0.86 and 0.89 accuracy in differentiating ALS and PUMN patients from controls, while DT MRI distinguished the two groups from controls with 0.78 and 0.92 accuracy. In ALS vs controls, the combination of cortical thickness and DT MRI metrics (combined model improved the classification pattern (0.91 accuracy. In the validation cohort, the best accuracy was reached by DT MRI (0.87 and 0.95 accuracy in ALS and PUMN vs mimic disorders. The combined model distinguished ALS and PUMN patients from mimic syndromes with 0.87 and 0.94 accuracy. A multimodal MRI approach that incorporates motor cortical and white matter alterations yields statistically significant improvement in accuracy over using each modality separately in the individual MND patient classification. DT MRI represents the most powerful tool to distinguish MND from mimic disorders.

Corroboration of in utero MRI using post-mortem MRI and autopsy in foetuses with CNS abnormalities

International Nuclear Information System (INIS)

Whitby, E.H.; Variend, S.; Rutter, S.; Paley, M.N.J.; Wilkinson, I.D.; Davies, N.P.; Sparey, C.; Griffiths, P.D.

2004-01-01

AIMS: To corroborate the findings of in utero magnetic resonance imaging (MRI) with autopsy and post-mortem MRI in cases of known or suspected central nervous system (CNS) abnormalities on ultrasound and to compare the diagnostic accuracy of ante-natal ultrasound and in utero MRI. METHODS: Twelve pregnant women, whose foetuses had suspected central nervous system abnormalities underwent in utero MRI. The foetuses were imaged using MRi before autopsy. The data were used to evaluate the diagnostic accuracy of in utero MRI when compared with a reference standard of autopsy and post-mortem MRI in 10 cases and post-mortem MRI alone in two cases. RESULTS: The diagnostic accuracy of antenatal ultrasound and in utero MRI in correctly characterizing brain and spine abnormalities were 42 and 100%, respectively. CONCLUSION: In utero MRI provides a useful adjuvant to antenatal ultrasound when assessing CNS abnormalities by providing more accurate anatomical information. Post-mortem MRI assists the diagnosis of macroscopic structural abnormalities

Structural MRI markers of brain aging early after ischemic stroke.

Science.gov (United States)

Werden, Emilio; Cumming, Toby; Li, Qi; Bird, Laura; Veldsman, Michele; Pardoe, Heath R; Jackson, Graeme; Donnan, Geoffrey A; Brodtmann, Amy

2017-07-11

To examine associations between ischemic stroke, vascular risk factors, and MRI markers of brain aging. Eighty-one patients (mean age 67.5 ± 13.1 years, 31 left-sided, 61 men) with confirmed first-ever (n = 66) or recurrent (n = 15) ischemic stroke underwent 3T MRI scanning within 6 weeks of symptom onset (mean 26 ± 9 days). Age-matched controls (n = 40) completed identical testing. Multivariate regression analyses examined associations between group membership and MRI markers of brain aging (cortical thickness, total brain volume, white matter hyperintensity [WMH] volume, hippocampal volume), normalized against intracranial volume, and the effects of vascular risk factors on these relationships. First-ever stroke was associated with smaller hippocampal volume ( p = 0.025) and greater WMH volume ( p = 0.004) relative to controls. Recurrent stroke was in turn associated with smaller hippocampal volume relative to both first-ever stroke ( p = 0.017) and controls ( p = 0.001). These associations remained significant after adjustment for age, sex, education, and, in stroke patients, infarct volume. Total brain volume was not significantly smaller in first-ever stroke patients than in controls ( p = 0.056), but the association became significant after further adjustment for atrial fibrillation ( p = 0.036). Cortical thickness and brain volumes did not differ as a function of stroke type, infarct volume, or etiology. Brain structure is likely to be compromised before ischemic stroke by vascular risk factors. Smaller hippocampal and total brain volumes and increased WMH load represent proxies for underlying vascular brain injury. Copyright © 2017 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.

Research progress of functional MRI in depression

International Nuclear Information System (INIS)

Xie Shenghui; Niu Guangming; Han Xiaodong; Qiao Pengfei

2013-01-01

The mood disorders of depression are associated with abnormalities of brain structure and function, and exploring their pathological mechanism has important significance for the choice of treatment and the curative effect evaluation. In recent years, the research of MRI on brain structure and function of depression has made great progress, especially in functional magnetic resonance imaging (fMRI). fMRI can detect the functional change in real time, and also can display the activity of brain and changes in the nerve pathways in patients with depression. This article summarizes the present research situation and progress of MRI in the diagnosis of depression. (authors)

Surface-Based fMRI-Driven Diffusion Tractography in the Presence of Significant Brain Pathology: A Study Linking Structure and Function in Cerebral Palsy

Science.gov (United States)

Cunnington, Ross; Boyd, Roslyn N.; Rose, Stephen E.

2016-01-01

Diffusion MRI (dMRI) tractography analyses are difficult to perform in the presence of brain pathology. Automated methods that rely on cortical parcellation for structural connectivity studies often fail, while manually defining regions is extremely time consuming and can introduce human error. Both methods also make assumptions about structure-function relationships that may not hold after cortical reorganisation. Seeding tractography with functional-MRI (fMRI) activation is an emerging method that reduces these confounds, but inherent smoothing of fMRI signal may result in the inclusion of irrelevant pathways. This paper describes a novel fMRI-seeded dMRI-analysis pipeline based on surface-meshes that reduces these issues and utilises machine-learning to generate task specific white matter pathways, minimising the requirement for manually-drawn ROIs. We directly compared this new strategy to a standard voxelwise fMRI-dMRI approach, by investigating correlations between clinical scores and dMRI metrics of thalamocortical and corticomotor tracts in 31 children with unilateral cerebral palsy. The surface-based approach successfully processed more participants (87%) than the voxel-based approach (65%), and provided significantly more-coherent tractography. Significant correlations between dMRI metrics and five clinical scores of function were found for the more superior regions of these tracts. These significant correlations were stronger and more frequently found with the surface-based method (15/20 investigated were significant; R2 = 0.43–0.73) than the voxelwise analysis (2 sig. correlations; 0.38 & 0.49). More restricted fMRI signal, better-constrained tractography, and the novel track-classification method all appeared to contribute toward these differences. PMID:27487011

3D MRI Modeling of Thin and Spatially Complex Soft Tissue Structures without Shrinkage: Lamprey Myosepta as an Example.

Science.gov (United States)

Wood, Bradley M; Jia, Guang; Carmichael, Owen; McKlveen, Kevin; Homberger, Dominique G

2018-05-12

3D imaging techniques enable the non-destructive analysis and modeling of complex structures. Among these, MRI exhibits good soft tissue contrast, but is currently less commonly used for non-clinical research than x-ray CT, even though the latter requires contrast-staining that shrinks and distorts soft tissues. When the objective is the creation of a realistic and complete 3D model of soft tissue structures, MRI data are more demanding to acquire and visualize and require extensive post-processing because they comprise non-cubic voxels with dimensions that represent a trade-off between tissue contrast and image resolution. Therefore, thin soft tissue structures with complex spatial configurations are not always visible in a single MRI dataset, so that standard segmentation techniques are not sufficient for their complete visualization. By using the example of the thin and spatially complex connective tissue myosepta in lampreys, we developed a workflow protocol for the selection of the appropriate parameters for the acquisition of MRI data and for the visualization and 3D modeling of soft tissue structures. This protocol includes a novel recursive segmentation technique for supplementing missing data in one dataset with data from another dataset to produce realistic and complete 3D models. Such 3D models are needed for the modeling of dynamic processes, such as the biomechanics of fish locomotion. However, our methodology is applicable to the visualization of any thin soft tissue structures with complex spatial configurations, such as fasciae, aponeuroses, and small blood vessels and nerves, for clinical research and the further exploration of tensegrity. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... structures of the brain and can also provide functional information (fMRI) in selected cases. MR images of ... Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain ...

Structural changes in socio-affective networks: Multi-modal MRI findings in long-term meditation practitioners.

Science.gov (United States)

Engen, Haakon G; Bernhardt, Boris C; Skottnik, Leon; Ricard, Matthieu; Singer, Tania

2017-08-31

Our goal was to assess the effects of long-term mental training in socio-affective skills on structural brain networks. We studied a group of long-term meditation practitioners (LTMs) who have focused on cultivating socio-affective skills using loving-kindness and compassion meditation for an average of 40k h, comparing these to meditation-naïve controls. To maximize homogeneity of prior practice, LTMs were included only if they had undergone extensive full-time meditation retreats in the same center. MRI-based cortical thickness analysis revealed increased thickness in the LTM cohort relative to meditation-native controls in fronto-insular cortices. To identify functional networks relevant for the generation of socio-affective states, structural imaging analysis were complemented by fMRI analysis in LTMs, showing amplitude increases during a loving-kindness meditation session relative to non-meditative rest in multiple prefrontal and insular regions bilaterally. Importantly, functional findings partially overlapped with regions of cortical thickness increases in the left ventrolateral prefrontal cortex and anterior insula, suggesting that these regions may play a central role in the generation of emotional states relevant for the meditative practice. Our multi-modal MRI approach revealed structural changes in LTMs who have cultivated loving-kindness and compassion for a significant period of their life in functional networks activated by these practices. These preliminary cross-sectional findings motivate future longitudinal work studying brain plasticity following the regular practice of skills aiming at enhancing human altruism and prosocial motivation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Diffusion, confusion and functional MRI

International Nuclear Information System (INIS)

Le Bihan, Denis

2012-01-01

Diffusion MRI has been introduced in 1985 and has had a very successful life on its own. While it has become a standard for imaging stroke and white matter disorders, the borders between diffusion MRI and the general field of fMRI have always remained fuzzy. First, diffusion MRI has been used to obtain images of brain function, based on the idea that diffusion MRI could also be made sensitive to blood flow, through the intra-voxel incoherent motion (IVIM) concept. Second, the IVIM concept helped better understand the contribution from different vasculature components to the BOLD fMRI signal. Third, it has been shown recently that a genuine fMRI signal can be obtained with diffusion MRI. This 'DfMRI' signal is notably different from the BOLD fMRI signal, especially for its much faster response to brain activation both at onset and offset, which points out to structural changes in the neural tissues, perhaps such as cell swelling, occurring in activated neural tissue. This short article reviews the major steps which have paved the way for this exciting development, underlying how technical progress with MRI equipment has each time been instrumental to expand the horizon of diffusion MRI toward the field of fMRI. (authors)

Multicentre structural and functional MRI

OpenAIRE

Gountouna, Viktoria-Eleni

2014-01-01

Neuroimaging techniques are likely to continue to improve our understanding of the brain in health and disease, but studies tend to be small, based in one imaging centre and of uncertain generalisability. Multicentre imaging studies therefore have great appeal but it is not yet clear under which circumstances data from different scanners can be combined. The successful harmonisation of multiple Magnetic Resonance Imaging (MRI) machines will increase study power, flexibility and...

A variational image-based approach to the correction of susceptibility artifacts in the alignment of diffusion weighted and structural MRI.

Science.gov (United States)

Tao, Ran; Fletcher, P Thomas; Gerber, Samuel; Whitaker, Ross T

2009-01-01

This paper presents a method for correcting the geometric and greyscale distortions in diffusion-weighted MRI that result from inhomogeneities in the static magnetic field. These inhomogeneities may due to imperfections in the magnet or to spatial variations in the magnetic susceptibility of the object being imaged--so called susceptibility artifacts. Echo-planar imaging (EPI), used in virtually all diffusion weighted acquisition protocols, assumes a homogeneous static field, which generally does not hold for head MRI. The resulting distortions are significant, sometimes more than ten millimeters. These artifacts impede accurate alignment of diffusion images with structural MRI, and are generally considered an obstacle to the joint analysis of connectivity and structure in head MRI. In principle, susceptibility artifacts can be corrected by acquiring (and applying) a field map. However, as shown in the literature and demonstrated in this paper, field map corrections of susceptibility artifacts are not entirely accurate and reliable, and thus field maps do not produce reliable alignment of EPIs with corresponding structural images. This paper presents a new, image-based method for correcting susceptibility artifacts. The method relies on a variational formulation of the match between an EPI baseline image and a corresponding T2-weighted structural image but also specifically accounts for the physics of susceptibility artifacts. We derive a set of partial differential equations associated with the optimization, describe the numerical methods for solving these equations, and present results that demonstrate the effectiveness of the proposed method compared with field-map correction.

Identifying individuals at high risk of psychosis: predictive utility of Support Vector Machine using structural and functional MRI data

Directory of Open Access Journals (Sweden)

Isabel eValli

2016-04-01

Full Text Available The identification of individuals at high risk of developing psychosis is entirely based on clinical assessment, associated with limited predictive potential. There is therefore increasing interest in the development of biological markers that could be used in clinical practice for this purpose. We studied 25 individuals with an At Risk Mental State for psychosis and 25 healthy controls using structural MRI, and functional MRI in conjunction with a verbal memory task. Data were analysed using a standard univariate analysis, and with Support Vector Machine (SVM, a multivariate pattern recognition technique that enables statistical inferences to be made at the level of the individual, yielding results with high translational potential. The application of SVM to structural MRI data permitted the identification of individuals at high risk of psychosis with a sensitivity of 68% and a specificity of 76%, resulting in an accuracy of 72% (p<0.001. Univariate volumetric between-group differences did not reach statistical significance. In contrast, the univariate fMRI analysis identified between-group differences (p<0.05 corrected while the application of SVM to the same data did not. Since SVM is well suited at identifying the pattern of abnormality that distinguishes two groups, whereas univariate methods are more likely to identify regions that individually are most different between two groups, our results suggest the presence of focal functional abnormalities in the context of a diffuse pattern of structural abnormalities in individuals at high clinical risk of psychosis.

Associations between MRI-defined structural pathology and generalized and localized knee pain - the Oulu Knee Osteoarthritis study.

Science.gov (United States)

Kaukinen, P; Podlipská, J; Guermazi, A; Niinimäki, J; Lehenkari, P; Roemer, F W; Nieminen, M T; Koski, J M; Arokoski, J P A; Saarakkala, S

2016-09-01

To determine the associations between multi-feature structural pathology assessed using magnetic resonance imaging (MRI) and the presence of knee pain, and to determine the associations between the locations of structural changes and different knee pain patterns. Eighty symptomatic subjects with knee pain and suspicion or diagnosis of knee OA and 63 asymptomatic subjects underwent knee MRI. Severity of structural changes was graded by MRI Osteoarthritis Knee Score (MOAKS) in separate knee locations. The associations between cartilage damage, bone marrow lesions (BMLs), osteophytes, Hoffa's synovitis, effusion-synovitis, meniscal damage and structural pathologies in ligaments, tendons and bursas and both the presence of pain and the knee pain patterns were assessed. The presence of Hoffa's synovitis (adjusted RR 1.6, 95% CI 1.2-1.3) and osteophytes in any region (2.07, 1.19-3.60) was significantly associated with the presence of pain. Any Hoffa's synovitis was associated with patellar pain (adjusted RR 4.70, 95% CI 1.19-3.60) and moderate-to-severe Hoffa's synovitis with diffuse pain (2.25, 1.13-4.50). Medial knee pain was associated with cartilage loss in the medial tibia (adjusted RR 2.66, 95% CI 1.22-5.80), osteophytes in the medial tibia (2.66, 1.17-6.07) and medial femur (2.55, 1.07-6.09), medial meniscal maceration (2.20, 1.01-4.79) and anterior meniscal extrusions (2.78, 1.14-6.75). Hoffa's synovitis and osteophytes were strongly associated with the presence of knee pain. Medial pain was associated most often with medially located structural pathologies. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Magnetic Resonance Imaging (MRI) -- Head

Medline Plus

Full Text Available ... can also provide functional information (fMRI) in selected cases. MR images of the brain and other cranial structures are clearer and more detailed than with other imaging methods. This detail makes MRI an invaluable tool in early diagnosis and evaluation of many conditions, ...

Bold-Independent Computational Entropy Assesses Functional Donut-Like Structures in Brain fMRI Images.

Science.gov (United States)

Peters, James F; Ramanna, Sheela; Tozzi, Arturo; İnan, Ebubekir

2017-01-01

We introduce a novel method for the measurement of information level in fMRI (functional Magnetic Resonance Imaging) neural data sets, based on image subdivision in small polygons equipped with different entropic content. We show how this method, called maximal nucleus clustering (MNC), is a novel, fast and inexpensive image-analysis technique, independent from the standard blood-oxygen-level dependent signals. MNC facilitates the objective detection of hidden temporal patterns of entropy/information in zones of fMRI images generally not taken into account by the subjective standpoint of the observer. This approach befits the geometric character of fMRIs. The main purpose of this study is to provide a computable framework for fMRI that not only facilitates analyses, but also provides an easily decipherable visualization of structures. This framework commands attention because it is easily implemented using conventional software systems. In order to evaluate the potential applications of MNC, we looked for the presence of a fourth dimension's distinctive hallmarks in a temporal sequence of 2D images taken during spontaneous brain activity. Indeed, recent findings suggest that several brain activities, such as mind-wandering and memory retrieval, might take place in the functional space of a four dimensional hypersphere, which is a double donut-like structure undetectable in the usual three dimensions. We found that the Rényi entropy is higher in MNC areas than in the surrounding ones, and that these temporal patterns closely resemble the trajectories predicted by the possible presence of a hypersphere in the brain.

Decoupling capabilities of split-loop resonator structure for 7 Tesla MRI surface array coils

Science.gov (United States)

Hurshkainen, A.; Kurdjumov, S.; Simovski, C.; Glybovski, S.; Melchakova, I.; van den Berg, C. A. T.; Raaijmakers, A.; Belov, P.

2017-09-01

In this work we studied electromagnetic properties of one-dimentional periodic structures composed of split-loop res-onators (SLRs) and investigated their capabilities in decoupling of two dipole antennas for full-body magnetic resonance imaging (MRI). Two different finite structures comprising a single-SLR and a double-SLR constitutive elements were studied. Numerical simulations of the structures were performed to evaluate their decoupling capabilities. As it was demonstrated two dipole antennas equipped with either a single or a double-SLR structure exhibit high isolation even for an electrically short distance between the dipoles. Double-SLR structure while dramatically improving isolation of the dipoles keeps the field created by each of the decoupled dipoles comparable with one of a single dipole inside the target area.

Brain without anatomy: construction and comparison of fully network-driven structural MRI connectomes.

Directory of Open Access Journals (Sweden)

Olga Tymofiyeva

Full Text Available MRI connectomics methods treat the brain as a network and provide new information about its organization, efficiency, and mechanisms of disruption. The most commonly used method of defining network nodes is to register the brain to a standardized anatomical atlas based on the Brodmann areas. This approach is limited by inter-subject variability and can be especially problematic in the context of brain maturation or neuroplasticity (cerebral reorganization after brain damage. In this study, we combined different image processing and network theory methods and created a novel approach that enables atlas-free construction and connection-wise comparison of diffusion MRI-based brain networks. We illustrated the proposed approach in three age groups: neonates, 6-month-old infants, and adults. First, we explored a data-driven method of determining the optimal number of equal-area nodes based on the assumption that all cortical areas of the brain are connected and, thus, no part of the brain is structurally isolated. Second, to enable a connection-wise comparison, alignment to a "reference brain" was performed in the network domain within each group using a matrix alignment algorithm with simulated annealing. The correlation coefficients after pair-wise network alignment ranged from 0.6102 to 0.6673. To test the method's reproducibility, one subject from the 6-month-old group and one from the adult group were scanned twice, resulting in correlation coefficients of 0.7443 and 0.7037, respectively. While being less than 1 due to parcellation and noise, statistically, these values were significantly higher than inter-subject values. Rotation of the parcellation largely explained the variability. Through the abstraction from anatomy, the developed framework allows for a fully network-driven analysis of structural MRI connectomes and can be applied to subjects at any stage of development and with substantial differences in cortical anatomy.

[Recent advances in newborn MRI].

Science.gov (United States)

Morel, B; Hornoy, P; Husson, B; Bloch, I; Adamsbaum, C

2014-07-01

The accurate morphological exploration of the brain is a major challenge in neonatology that advances in magnetic resonance imaging (MRI) can now provide. MRI is the gold standard if an hypoxic ischemic pathology is suspected in a full term neonate. In prematures, the specific role of MRI remains to be defined, secondary to US in any case. We present a state of the art of hardware and software technical developments in MRI. The increase in magnetic field strength (3 tesla) and the emergence of new MRI sequences provide access to new information. They both have positive and negative consequences on the daily clinical data acquisition use. The semiology of brain imaging in full term newborns and prematures is more extensive and complex and thereby more difficult to interpret. The segmentation of different brain structures in the newborn, even very premature, is now available. It is now possible to dissociate the cortex and basal ganglia from the cerebral white matter, to calculate the volume of anatomical structures, which improves the morphometric quantification and the understanding of the normal and abnormal brain development. MRI is a powerful tool to analyze the neonatal brain. The relevance of the diagnostic contribution requires an adaptation of the parameters of the sequences to acquire and of the image processing methods. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

The two-year progression of structural and functional cerebral MRI in amyotrophic lateral sclerosis

Directory of Open Access Journals (Sweden)

R.A.L. Menke

2018-01-01

A longer period of follow-up, though necessarily involving more slowly-progressive cases, demonstrated widespread changes in both grey and white matter structural MRI measures. The mixed picture of regional decreases and increases in FC is compatible with compensatory change, in what should be viewed as a brain-based disease characterised by larger-scale disintegration of motor and frontal projection cerebral networks.

Three-dimensional MRI-linac intra-fraction guidance using multiple orthogonal cine-MRI planes

DEFF Research Database (Denmark)

Bjerre, Troels; Crijns, Sjoerd; Rosenschöld, Per Munck af

2013-01-01

The introduction of integrated MRI-radiation therapy systems will offer live intra-fraction imaging. We propose a feasible low-latency multi-plane MRI-linac guidance strategy. In this work we demonstrate how interleaved acquired, orthogonal cine-MRI planes can be used for low-latency tracking...... of the 3D trajectory of a soft-tissue target structure. The proposed strategy relies on acquiring a pre-treatment 3D breath-hold scan, extracting a 3D target template and performing template matching between this 3D template and pairs of orthogonal 2D cine-MRI planes intersecting the target motion path....... For a 60 s free-breathing series of orthogonal cine-MRI planes, we demonstrate that the method was capable of accurately tracking the respiration related 3D motion of the left kidney. Quantitative evaluation of the method using a dataset designed for this purpose revealed a translational error of 1.15 mm...

Three-dimensional MRI-linac intra-fraction guidance using multiple orthogonal cine-MRI planes.

Science.gov (United States)

Bjerre, Troels; Crijns, Sjoerd; af Rosenschöld, Per Munck; Aznar, Marianne; Specht, Lena; Larsen, Rasmus; Keall, Paul

2013-07-21

The introduction of integrated MRI-radiation therapy systems will offer live intra-fraction imaging. We propose a feasible low-latency multi-plane MRI-linac guidance strategy. In this work we demonstrate how interleaved acquired, orthogonal cine-MRI planes can be used for low-latency tracking of the 3D trajectory of a soft-tissue target structure. The proposed strategy relies on acquiring a pre-treatment 3D breath-hold scan, extracting a 3D target template and performing template matching between this 3D template and pairs of orthogonal 2D cine-MRI planes intersecting the target motion path. For a 60 s free-breathing series of orthogonal cine-MRI planes, we demonstrate that the method was capable of accurately tracking the respiration related 3D motion of the left kidney. Quantitative evaluation of the method using a dataset designed for this purpose revealed a translational error of 1.15 mm for a translation of 39.9 mm. We have demonstrated how interleaved acquired, orthogonal cine-MRI planes can be used for online tracking of soft-tissue target volumes.

In vitro MRI of brain development

International Nuclear Information System (INIS)

Rados, Marko; Judas, Milos; Kostovic, Ivica

2006-01-01

In this review, we demonstrate the developmental appearance, structural features, and reorganization of transient cerebral zones and structures in the human fetal brain using a correlative histological and MRI analysis. The analysis of postmortem aldehyde-fixed specimens (age range: 10 postovulatory weeks to term) revealed that, at 10 postovulatory weeks, the cerebral wall already has a trilaminar appearance and consists of: (1) a ventricular zone of high cell-packing density; (2) an intermediate zone; (3) the cortical plate (in a stage of primary consolidation) with high MRI signal intensity. The anlage of the hippocampus is present as a prominent bulging in the thin limbic telencephalon. The early fetal telencephalon impar also contains the first commissural fibers and fornix bundles in the septal area. The ganglionic eminence is clearly visible as an expanded continuation of the proliferative ventricular zone. The basal ganglia showed an initial aggregation of cells. The most massive fiber system is in the hemispheric stalk, which is in continuity with thalamocortical fibers. During the mid-fetal period (15-22 postovulatory weeks), the typical fetal lamination pattern develops and the cerebral wall consists of the following zones: (a) a marginal zone (visible on MRI exclusively in the hippocampus); (b) the cortical plate with high cell-packing density and high MRI signal intensity; (c) the subplate zone, which is the most prominent zone rich in extracellular matrix and with a very low MRI signal intensity; (d) the intermediate zone (fetal 'white matter'); (e) the subventricular zone; (f) the periventricular fiber-rich zone; (g) the ventricular zone. The ganglionic eminence is still a very prominent structure with an intense proliferative activity. During the next period (22-26 postovulatory weeks), there is the developmental peak of transient MRI features, caused by the high content of hydrophyllic extracellular matrix in the subplate zone and the accumulation

Functional MRI of the patellofemoral joint: comparison of ultrafast MRI, motion-triggered cine MRI and static MRI

Energy Technology Data Exchange (ETDEWEB)

Muhle, C. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Brossmann, J. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Melchert, U.H. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Schroeder, C. [Radiologische Abt., Universitaets-Kinderklinik, Christian-Albrechts-Universitaet, Kiel (Germany); Boer, R. de [Philips Medical Systems, Best (Netherlands); Spielmann, R.P. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Heller, M. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany)

1995-12-31

To evaluate the feasibility and usefulness of ultrafast MRI (u), patellar tracking from 30 of flexion to knee extension (0 ) was analysed and compared with motion-triggered cine MRI (m) and a static MRI technique (s). The different imaging methods were compared in respect of the patellofemoral relationship, the examination time and image quality. Eight healthy subjects and four patients (in total 18 joints) with patellar subluxation or luxation were examined. Significant differences between the static MRI series without quadriceps contraction and the functional MRI studies (motion-triggered cine MRI and ultrafast MRI) were found for the patellar tilt angle. In the dynamic joint studies there was no statistical difference of the regression coefficients between the motion-triggered cine MRI studies and the ultrafast MRI studies. The findings of the functional MRI studies compared with the static MRI images were significantly different for the lateralisation of the patella, expressed by the lateral patellar displacement and bisect offset. No significant differences in patellar lateralisation were found between motion-triggered cine MRI and ultrafast MRI. Ultrafast MRI was superior to motion-triggered cine MRI in terms of the reduction in imaging time and improvement of the image quality. (orig.)

Functional MRI of the patellofemoral joint: comparison of ultrafast MRI, motion-triggered cine MRI and static MRI

International Nuclear Information System (INIS)

Muhle, C.; Brossmann, J.; Melchert, U.H.; Schroeder, C.; Boer, R. de; Spielmann, R.P.; Heller, M.

1995-01-01

To evaluate the feasibility and usefulness of ultrafast MRI (u), patellar tracking from 30 of flexion to knee extension (0 ) was analysed and compared with motion-triggered cine MRI (m) and a static MRI technique (s). The different imaging methods were compared in respect of the patellofemoral relationship, the examination time and image quality. Eight healthy subjects and four patients (in total 18 joints) with patellar subluxation or luxation were examined. Significant differences between the static MRI series without quadriceps contraction and the functional MRI studies (motion-triggered cine MRI and ultrafast MRI) were found for the patellar tilt angle. In the dynamic joint studies there was no statistical difference of the regression coefficients between the motion-triggered cine MRI studies and the ultrafast MRI studies. The findings of the functional MRI studies compared with the static MRI images were significantly different for the lateralisation of the patella, expressed by the lateral patellar displacement and bisect offset. No significant differences in patellar lateralisation were found between motion-triggered cine MRI and ultrafast MRI. Ultrafast MRI was superior to motion-triggered cine MRI in terms of the reduction in imaging time and improvement of the image quality. (orig.)

Structural MRI correlates of amyotrophic lateral sclerosis progression.

Science.gov (United States)

Senda, Joe; Atsuta, Naoki; Watanabe, Hirohisa; Bagarinao, Epifanio; Imai, Kazunori; Yokoi, Daichi; Riku, Yuichi; Masuda, Michihito; Nakamura, Ryoichi; Watanabe, Hazuki; Ito, Mizuki; Katsuno, Masahisa; Naganawa, Shinji; Sobue, Gen

2017-11-01

Amyotrophic lateral sclerosis (ALS) presents with varying degrees of brain degeneration that can extend beyond the corticospinal tract (CST). Furthermore, the clinical course and progression of ALS varies widely. Brain degeneration detected using structural MRI could reflect disease progression. On study registration, 3-Tesla volumetric MRI and diffusion tensor imaging scans were obtained at baseline in 38 healthy controls and 67 patients with sporadic ALS. Patients had Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) scores of ≥36 and did not have the chromosome 9, open reading frame 72 repeat expansion. Six months later, changes in ALSFRS-R (ΔALSFRS-R) scores were calculated and patients were grouped into three categories, namely, patients with slow progression with ΔALSFRS-R scores ≤3 (n=19), intermediate progression with ΔALSFRS-R scores =4, 5 and 6 (n=36) and rapid progression with ΔALSFRS-R scores ≥7 (n=12). We analysed voxel-based morphometry and tract-based spatial statistics among these subgroups and controls. In comparison with controls, patients with ALS showed grey matter atrophy and decreased fractional anisotropy beyond the motor cortex and CST, especially in the frontotemporal lobes and basal ganglia. Moreover, the degree of change was highly proportional to ΔALSFRS-R at the 6-month assessment. A more rapid disease progression and poorer functional decline were associated with greater involvement of the extra-motor cortex and basal ganglia, suggesting that the spatial extent of brain involvement can be an indicator of the progression in ALS. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Recent applications of UHF-MRI in the study of human brain function and structure : a review

NARCIS (Netherlands)

Van der Zwaag, W.; Schäfer, Andreas; Marques, José P; Turner, R.; Trampel, Robert

The increased availability of ultra-high-field (UHF) MRI has led to its application in a wide range of neuroimaging studies, which are showing promise in transforming fundamental approaches to human neuroscience. This review presents recent work on structural and functional brain imaging, at 7 T and

Practical aspects of MRI of the prostate

Directory of Open Access Journals (Sweden)

Dragoș Cuzino

2014-12-01

Full Text Available The article presents the main aspects of sectional anatomy, lymph nodes and adjacent structures as well as MRI examination standard protocol for prostate cancer diagnosis. Using MRI multiparametric examination we succeed in classifying efficiently the malignant prostatic tumors using PI- RADS system. Also, using MRI multiparametric examination we can evaluate the effectiveness of prostate cancer treatment

Simultaneous evaluation of brain tumour metabolism, structure and blood volume using [{sup 18}F]-fluoroethyltyrosine (FET) PET/MRI: feasibility, agreement and initial experience

Energy Technology Data Exchange (ETDEWEB)

Henriksen, Otto M.; Hansen, Adam E.; Law, Ian [Copenhagen University Hospital Rigshospitalet Blegdamsvej, Department of Clinical Physiology Nuclear Medicine and PET, Copenhagen (Denmark); Larsen, Vibeke A. [Copenhagen University Hospital Rigshospitalet Blegdamsvej, Department of Radiology, Copenhagen (Denmark); Muhic, Aida; Poulsen, Hans S. [Copenhagen University Hospital Rigshospitalet Blegdamsvej, Department of Oncology, Copenhagen (Denmark); Larsson, Henrik B.W. [Copenhagen University Hospital Rigshospitalet Glostrup, Functional Imaging Unit, Department of Clinical Physiology Nuclear Medicine and PET, Glostrup (Denmark)

2016-01-15

Both [{sup 18}F]-fluoroethyltyrosine (FET) PET and blood volume (BV) MRI supplement routine T1-weighted contrast-enhanced MRI in gliomas, but whether the two modalities provide identical or complementary information is unresolved. The aims of the study were to investigate the feasibility of simultaneous structural MRI, BV MRI and FET PET of gliomas using an integrated PET/MRI scanner and to assess the spatial and quantitative agreement in tumour imaging between BV MRI and FET PET. A total of 32 glioma patients underwent a 20-min static simultaneous PET/MRI acquisition on a Siemens mMR system 20 min after injection of 200 MBq FET. The MRI protocol included standard structural MRI and dynamic susceptibility contrast (DSC) imaging for BV measurements. Maximal relative tumour FET uptake (TBR{sub max}) and BV (rBV{sub max}), and Dice coefficients were calculated to assess the quantitative and spatial congruence in the tumour volumes determined by FET PET, BV MRI and contrast-enhanced MRI. FET volume and TBR{sub max} were higher in BV-positive than in BV-negative scans, and both VOL{sub BV} and rBV{sub max} were higher in FET-positive than in FET-negative scans. TBR{sub max} and rBV{sub max} were positively correlated (R{sup 2} = 0.59, p < 0.001). FET and BV positivity were in agreement in only 26 of the 32 patients and in 42 of 63 lesions, and spatial congruence in the tumour volumes as assessed by the Dice coefficients was generally poor with median Dice coefficients exceeding 0.1 in less than half the patients positive on at least one modality for any pair of modalities. In 56 % of the patients susceptibility artefacts in DSC BV maps overlapped the tumour on MRI. The study demonstrated that although tumour volumes determined by BV MRI and FET PET were quantitatively correlated, their spatial congruence in a mixed population of treated glioma patients was generally poor, and the modalities did not provide the same information in this population of patients. Combined

MRI anatomy of schizophrenia.

Science.gov (United States)

McCarley, R W; Wible, C G; Frumin, M; Hirayasu, Y; Levitt, J J; Fischer, I A; Shenton, M E

1999-05-01

Structural magnetic resonance imaging (MRI) data have provided much evidence in support of our current view that schizophrenia is a brain disorder with altered brain structure, and consequently involving more than a simple disturbance in neurotransmission. This review surveys 118 peer-reviewed studies with control group from 1987 to May 1998. Most studies (81%) do not find abnormalities of whole brain/intracranial contents, while lateral ventricle enlargement is reported in 77%, and third ventricle enlargement in 67%. The temporal lobe was the brain parenchymal region with the most consistently documented abnormalities. Volume decreases were found in 62% of 37 studies of whole temporal lobe, and in 81% of 16 studies of the superior temporal gyrus (and in 100% with gray matter separately evaluated). Fully 77% of the 30 studies of the medial temporal lobe reported volume reduction in one or more of its constituent structures (hippocampus, amygdala, parahippocampal gyrus). Despite evidence for frontal lobe functional abnormalities, structural MRI investigations less consistently found abnormalities, with 55% describing volume reduction. It may be that frontal lobe volume changes are small, and near the threshold for MRI detection. The parietal and occipital lobes were much less studied; about half of the studies showed positive findings. Most studies of cortical gray matter (86%) found volume reductions were not diffuse, but more pronounced in certain areas. About two thirds of the studies of subcortical structures of thalamus, corpus callosum and basal ganglia (which tend to increase volume with typical neuroleptics), show positive findings, as do almost all (91%) studies of cavum septi pellucidi (CSP). Most data were consistent with a developmental model, but growing evidence was compatible also with progressive, neurodegenerative features, suggesting a "two-hit" model of schizophrenia, for which a cellular hypothesis is discussed. The relationship of clinical

Whole-body MRI screening

Energy Technology Data Exchange (ETDEWEB)

Puls, Ralf [HELIOS Klinikum Erfurt (Germany). Inst. of Diagnostic and Interventional Radiology and Neuroradiology; Hosten, Norbert (ed.) [Universitaetsklinikum Greifswald (Germany). Diagnostic Radiology and Neuroradiology

2014-07-01

The advent of dedicated whole-body MRI scanners has made it possible to image the human body from head to toe with excellent spatial resolution and with the sensitivity and specificity of conventional MR systems. A comprehensive screening examination by MRI relies on fast image acquisition, and this is now feasible owing to several very recent developments, including multichannel techniques, new surface coil systems, and automatic table movement. The daily analysis of whole-body MRI datasets uncovers many incidental findings, which are discussed by an interdisciplinary advisory board of physicians from all specialties. This book provides a systematic overview of these incidental findings with the aid of approximately 240 high-quality images. The radiologists involved in the project have written chapters on each organ system, presenting a structured compilation of the most common findings, their morphologic appearances on whole-body MRI, and guidance on their clinical management. Chapters on technical and ethical issues are also included. It is hoped that this book will assist other diagnosticians in deciding how to handle the most common incidental findings encountered when performing whole-body MRI.

Whole-body MRI screening

International Nuclear Information System (INIS)

Puls, Ralf; Hosten, Norbert

2014-01-01

The advent of dedicated whole-body MRI scanners has made it possible to image the human body from head to toe with excellent spatial resolution and with the sensitivity and specificity of conventional MR systems. A comprehensive screening examination by MRI relies on fast image acquisition, and this is now feasible owing to several very recent developments, including multichannel techniques, new surface coil systems, and automatic table movement. The daily analysis of whole-body MRI datasets uncovers many incidental findings, which are discussed by an interdisciplinary advisory board of physicians from all specialties. This book provides a systematic overview of these incidental findings with the aid of approximately 240 high-quality images. The radiologists involved in the project have written chapters on each organ system, presenting a structured compilation of the most common findings, their morphologic appearances on whole-body MRI, and guidance on their clinical management. Chapters on technical and ethical issues are also included. It is hoped that this book will assist other diagnosticians in deciding how to handle the most common incidental findings encountered when performing whole-body MRI.

Assessment of pulmonary structure-function relationships in young children and adolescents with cystic fibrosis by multivolume proton-MRI and CT.

Science.gov (United States)

Pennati, Francesca; Roach, David J; Clancy, John P; Brody, Alan S; Fleck, Robert J; Aliverti, Andrea; Woods, Jason C

2018-02-19

Lung disease is the most frequent cause of morbidity and mortality in patients with cystic fibrosis (CF), and there is a shortage of sensitive biomarkers able to regionally monitor disease progression and to assess early responses to therapy. To determine the feasibility of noncontrast-enhanced multivolume MRI, which assesses intensity changes between expiratory and inspiratory breath-hold images, to detect and quantify regional ventilation abnormalities in CF lung disease, with a focus on the structure-function relationship. Retrospective. Twenty-nine subjects, including healthy young children (n = 9, 7-37 months), healthy adolescents (n = 4, 14-22 years), young children with CF lung disease (n = 10, 7-47 months), and adolescents with CF lung disease (n = 6, 8-18 years) were studied. 3D spoiled gradient-recalled sequence at 1.5T. Subjects were scanned during breath-hold at functional residual capacity (FRC) and total lung capacity (TLC) through noncontrast-enhanced MRI and CT. Expiratory-inspiratory differences in MR signal-intensity (Δ 1 H-MRI) and CT-density (ΔHU) were computed to estimate regional ventilation. MR and CT images were also evaluated using a CF-specific scoring system. Quadratic regression, Spearman's correlation, one-way analysis of variance (ANOVA). Δ 1 H-MRI maps were sensitive to ventilation heterogeneity related to gravity dependence in healthy lung and to ventilation impairment in CF lung disease. A high correlation was found between MRI and CT ventilation maps (R 2  = 0.79, P < 0.001). Globally, Δ 1 H-MRI and ΔHU decrease with increasing morphological score (respectively, R 2  = 0.56, P < 0.001 and R 2  = 0.31, P < 0.001). Locally, Δ 1 H-MRI was higher in healthy regions (median 15%) compared to regions with bronchiectasis, air trapping, consolidation, and to segments fed by airways with bronchial wall thickening (P < 0.001). Multivolume noncontrast-enhanced MRI, as a nonionizing imaging

A Comparison of Supervised Machine Learning Algorithms and Feature Vectors for MS Lesion Segmentation Using Multimodal Structural MRI

Science.gov (United States)

Sweeney, Elizabeth M.; Vogelstein, Joshua T.; Cuzzocreo, Jennifer L.; Calabresi, Peter A.; Reich, Daniel S.; Crainiceanu, Ciprian M.; Shinohara, Russell T.

2014-01-01

Machine learning is a popular method for mining and analyzing large collections of medical data. We focus on a particular problem from medical research, supervised multiple sclerosis (MS) lesion segmentation in structural magnetic resonance imaging (MRI). We examine the extent to which the choice of machine learning or classification algorithm and feature extraction function impacts the performance of lesion segmentation methods. As quantitative measures derived from structural MRI are important clinical tools for research into the pathophysiology and natural history of MS, the development of automated lesion segmentation methods is an active research field. Yet, little is known about what drives performance of these methods. We evaluate the performance of automated MS lesion segmentation methods, which consist of a supervised classification algorithm composed with a feature extraction function. These feature extraction functions act on the observed T1-weighted (T1-w), T2-weighted (T2-w) and fluid-attenuated inversion recovery (FLAIR) MRI voxel intensities. Each MRI study has a manual lesion segmentation that we use to train and validate the supervised classification algorithms. Our main finding is that the differences in predictive performance are due more to differences in the feature vectors, rather than the machine learning or classification algorithms. Features that incorporate information from neighboring voxels in the brain were found to increase performance substantially. For lesion segmentation, we conclude that it is better to use simple, interpretable, and fast algorithms, such as logistic regression, linear discriminant analysis, and quadratic discriminant analysis, and to develop the features to improve performance. PMID:24781953

Magnetic Resonance Imaging (MRI) -- Head

Medline Plus

Full Text Available ... structures of the brain and can also provide functional information (fMRI) in selected cases. MR images of the brain and other cranial structures are clearer and more detailed than with other ...

Comparison of a fast 5-min knee MRI protocol with a standard knee MRI protocol. A multi-institutional multi-reader study

Energy Technology Data Exchange (ETDEWEB)

FitzGerald Alaia, Erin; Beltran, Luis S.; Garwood, Elisabeth; Burke, Christopher J.; Gyftopoulos, Soterios [NYU Langone Medical Center, Department of Radiology, Musculoskeletal Division, New York, NY (United States); Benedick, Alex [Case Western Reserve University, School of Medicine, Cleveland, OH (United States); Obuchowski, Nancy A. [Cleveland Clinic, Department of Quantitative Health Sciences, Cleveland, OH (United States); Polster, Joshua M.; Schils, Jean; Subhas, Naveen [Cleveland Clinic, Department of Radiology, Musculoskeletal Division, Cleveland, OH (United States); Chang, I. Yuan Joseph [Texas Scottish Rite Hospital for Children, Dallas, TX (United States)

2018-01-15

To compare diagnostic performance of a 5-min knee MRI protocol to that of a standard knee MRI. One hundred 3 T (100 patients, mean 38.8 years) and 50 1.5 T (46 patients, mean 46.4 years) MRIs, consisting of 5 fast, 2D multi-planar fast-spin-echo (FSE) sequences and five standard multiplanar FSE sequences, from two academic centers (1/2015-1/2016), were retrospectively reviewed by four musculoskeletal radiologists. Agreement between fast and standard (interprotocol agreement) and between standard (intraprotocol agreement) readings for meniscal, ligamentous, chondral, and bone pathology was compared for interchangeability. Frequency of major findings, sensitivity, and specificity was also tested for each protocol. Interprotocol agreement using fast MRI was similar to intraprotocol agreement with standard MRI (83.0-99.5%), with no excess disagreement (≤ 1.2; 95% CI, -4.2 to 3.8%), across all structures. Frequency of major findings (1.1-22.4% across structures) on fast and standard MRI was not significantly different (p ≥ 0.215), except more ACL tears on fast MRI (p = 0.021) and more cartilage defects on standard MRI (p < 0.001). Sensitivities (59-100%) and specificities (73-99%) of fast and standard MRI were not significantly different for meniscal and ligament tears (95% CI for difference, -0.08-0.08). For cartilage defects, fast MRI was slightly less sensitive (95% CI for difference, -0.125 to -0.01) but slightly more specific (95% CI for difference, 0.01-0.5) than standard MRI. A fast 5-min MRI protocol is interchangeable with and has similar accuracy to a standard knee MRI for evaluating internal derangement of the knee. (orig.)

Comparison of a fast 5-min knee MRI protocol with a standard knee MRI protocol. A multi-institutional multi-reader study

International Nuclear Information System (INIS)

FitzGerald Alaia, Erin; Beltran, Luis S.; Garwood, Elisabeth; Burke, Christopher J.; Gyftopoulos, Soterios; Benedick, Alex; Obuchowski, Nancy A.; Polster, Joshua M.; Schils, Jean; Subhas, Naveen; Chang, I. Yuan Joseph

2018-01-01

To compare diagnostic performance of a 5-min knee MRI protocol to that of a standard knee MRI. One hundred 3 T (100 patients, mean 38.8 years) and 50 1.5 T (46 patients, mean 46.4 years) MRIs, consisting of 5 fast, 2D multi-planar fast-spin-echo (FSE) sequences and five standard multiplanar FSE sequences, from two academic centers (1/2015-1/2016), were retrospectively reviewed by four musculoskeletal radiologists. Agreement between fast and standard (interprotocol agreement) and between standard (intraprotocol agreement) readings for meniscal, ligamentous, chondral, and bone pathology was compared for interchangeability. Frequency of major findings, sensitivity, and specificity was also tested for each protocol. Interprotocol agreement using fast MRI was similar to intraprotocol agreement with standard MRI (83.0-99.5%), with no excess disagreement (≤ 1.2; 95% CI, -4.2 to 3.8%), across all structures. Frequency of major findings (1.1-22.4% across structures) on fast and standard MRI was not significantly different (p ≥ 0.215), except more ACL tears on fast MRI (p = 0.021) and more cartilage defects on standard MRI (p < 0.001). Sensitivities (59-100%) and specificities (73-99%) of fast and standard MRI were not significantly different for meniscal and ligament tears (95% CI for difference, -0.08-0.08). For cartilage defects, fast MRI was slightly less sensitive (95% CI for difference, -0.125 to -0.01) but slightly more specific (95% CI for difference, 0.01-0.5) than standard MRI. A fast 5-min MRI protocol is interchangeable with and has similar accuracy to a standard knee MRI for evaluating internal derangement of the knee. (orig.)

Brain structure in women at risk of postpartum psychosis: an MRI study.

Science.gov (United States)

Fusté, Montserrat; Pauls, Astrid; Worker, Amanda; Reinders, Antje A T S; Simmons, Andrew; Williams, Steven C R; Haro, Josep M; Hazelgrove, Kate; Pawlby, Susan; Conroy, Susan; Vecchio, Costanza; Seneviratne, Gertrude; Pariante, Carmine M; Mehta, Mitul A; Dazzan, Paola

2017-12-18

Postpartum psychosis (PP) is the most severe psychiatric disorder associated with childbirth. The risk of PP is very high in women with a history of bipolar affective disorder or schizoaffective disorder. However, the neurobiological basis of PP remains poorly understood and no study has evaluated brain structure in women at risk of, or with, PP. We performed a cross-sectional study of 256 women at risk of PP and 21 healthy controls (HC) in the same postpartum period. Among women at risk, 11 who developed a recent episode of PP (PPE) (n = 2 with lifetime bipolar disorder; n = 9 psychotic disorder not otherwise specified) and 15 at risk women who did not develop an episode of PP (NPPE) (n = 10 with lifetime bipolar disorder; n = 1 with schizoaffective disorder; n = 1 with a history of PP in first-degree family member; n = 3 with previous PP). We obtained T1-weighted MRI scans at 3T and examined regional gray matter volumes with voxel-based morphometry and cortical thickness and surface area with Freesurfer. Women with PPE showed smaller anterior cingulate gyrus, superior temporal gyrus and parahippocampal gyrus compared to NPPE women. These regions also showed decreased surface area. Moreover, the NPPE group showed a larger superior and inferior frontal gyrus volume than the HC. These results should be interpreted with caution, as there were between-group differences in terms of duration of illness and interval between delivery and MRI acquisition. Nevertheless, these are the first findings to suggest that MRI can provide information on brain morphology that characterize those women at risk of PP more likely to develop an episode after childbirth.

MRI in gout

International Nuclear Information System (INIS)

Seidl, G.; Ullrich, R.; Trattnig, S.; Dominkus, M.; Morscher, M.; Aringer, M.; Imhof, H.

1996-01-01

The appearance of gouty tophus in magnetic resonance imaging (MRI) is characteristic. On T1- and T2-weighted SE images, the signal intensity of tophaceous lesions is similar to that of muscles. According to the histology, T2-weighted SE images demonstrate extremely hyperintense signals, which reflect the high protein content in the amorpheous center of the tophus. The microscopic urate crystals deposited there have no MRI signal and are of no further diagnostic impact. Vascularized granulation tissue surrounding the tophus center enhance after intervenous application of contrast agents (Gadolinium). The inflammed tophus is associated with local edema, causing high signal intensity. MRI is superior to plain radiography for early detection of intraosseous tophi. Involvement of anatomical structures such as ligaments and tendons can be evaluated sufficiently. For peripheral joints, axial slice orientation is most helpful. (orig.) [de

Nonconventional MRI and microstructural cerebral changes in multiple sclerosis

DEFF Research Database (Denmark)

Enzinger, Christian; Barkhof, Frederik; Ciccarelli, Olga

2015-01-01

on disease-associated changes. This Review summarizes the rapid technical progress in the use of MRI in patients with MS, with a focus on nonconventional structural MRI. We critically discuss the present utility of nonconventional MRI in MS, and provide an outlook on future applications, including clinical...

An in vivo MRI Template Set for Morphometry, Tissue Segmentation, and fMRI Localization in Rats

Science.gov (United States)

Valdés-Hernández, Pedro Antonio; Sumiyoshi, Akira; Nonaka, Hiroi; Haga, Risa; Aubert-Vásquez, Eduardo; Ogawa, Takeshi; Iturria-Medina, Yasser; Riera, Jorge J.; Kawashima, Ryuta

2011-01-01

Over the last decade, several papers have focused on the construction of highly detailed mouse high field magnetic resonance image (MRI) templates via non-linear registration to unbiased reference spaces, allowing for a variety of neuroimaging applications such as robust morphometric analyses. However, work in rats has only provided medium field MRI averages based on linear registration to biased spaces with the sole purpose of approximate functional MRI (fMRI) localization. This precludes any morphometric analysis in spite of the need of exploring in detail the neuroanatomical substrates of diseases in a recent advent of rat models. In this paper we present a new in vivo rat T2 MRI template set, comprising average images of both intensity and shape, obtained via non-linear registration. Also, unlike previous rat template sets, we include white and gray matter probabilistic segmentations, expanding its use to those applications demanding prior-based tissue segmentation, e.g., statistical parametric mapping (SPM) voxel-based morphometry. We also provide a preliminary digitalization of latest Paxinos and Watson atlas for anatomical and functional interpretations within the cerebral cortex. We confirmed that, like with previous templates, forepaw and hindpaw fMRI activations can be correctly localized in the expected atlas structure. To exemplify the use of our new MRI template set, were reported the volumes of brain tissues and cortical structures and probed their relationships with ontogenetic development. Other in vivo applications in the near future can be tensor-, deformation-, or voxel-based morphometry, morphological connectivity, and diffusion tensor-based anatomical connectivity. Our template set, freely available through the SPM extension website, could be an important tool for future longitudinal and/or functional extensive preclinical studies. PMID:22275894

An in vivo MRI Template Set for Morphometry, Tissue Segmentation, and fMRI Localization in Rats.

Science.gov (United States)

Valdés-Hernández, Pedro Antonio; Sumiyoshi, Akira; Nonaka, Hiroi; Haga, Risa; Aubert-Vásquez, Eduardo; Ogawa, Takeshi; Iturria-Medina, Yasser; Riera, Jorge J; Kawashima, Ryuta

2011-01-01

Over the last decade, several papers have focused on the construction of highly detailed mouse high field magnetic resonance image (MRI) templates via non-linear registration to unbiased reference spaces, allowing for a variety of neuroimaging applications such as robust morphometric analyses. However, work in rats has only provided medium field MRI averages based on linear registration to biased spaces with the sole purpose of approximate functional MRI (fMRI) localization. This precludes any morphometric analysis in spite of the need of exploring in detail the neuroanatomical substrates of diseases in a recent advent of rat models. In this paper we present a new in vivo rat T2 MRI template set, comprising average images of both intensity and shape, obtained via non-linear registration. Also, unlike previous rat template sets, we include white and gray matter probabilistic segmentations, expanding its use to those applications demanding prior-based tissue segmentation, e.g., statistical parametric mapping (SPM) voxel-based morphometry. We also provide a preliminary digitalization of latest Paxinos and Watson atlas for anatomical and functional interpretations within the cerebral cortex. We confirmed that, like with previous templates, forepaw and hindpaw fMRI activations can be correctly localized in the expected atlas structure. To exemplify the use of our new MRI template set, were reported the volumes of brain tissues and cortical structures and probed their relationships with ontogenetic development. Other in vivo applications in the near future can be tensor-, deformation-, or voxel-based morphometry, morphological connectivity, and diffusion tensor-based anatomical connectivity. Our template set, freely available through the SPM extension website, could be an important tool for future longitudinal and/or functional extensive preclinical studies.

Statistical analysis of MRI-only based dose planning

DEFF Research Database (Denmark)

Korsholm, M. E.; Waring, L. W.; Paulsen, Rasmus Reinhold

2012-01-01

. MRIonly based RT eliminates these errors and reduce the time and costs of a CT scan. The aim of this study is to investigate the dosimetric differences of a treatment plan when the dose calculation is based on MRI as compared to CT. Materials and Methods: Four diagnostic groups are investigated; 12...... as a clinically approved treatment plan. The treatment planning software is Eclipse v.10.0 (Varian Medical Systems). The dose calculation based on MRI data is evaluated in two different ways; a homogeneous density assigned MRI (MRI unit), where the entire body is assigned an HU equal to water and a heterogeneous...... density assigned MRI (MRI bulk) where in addition the CT segmented bone is transferred to the MRI and assigned an age dependent HU based on ICRU report 46. The CT based clinical treatment plan and structure set are registered to the corresponding MRI unit and MRI bulk. The body is outlined on both the MRI...

Magnetic Resonance Imaging (MRI) -- Head

Medline Plus

Full Text Available ... detailed pictures of the brain and other cranial structures that are clearer and more detailed than other ... tissues, bone and virtually all other internal body structures. MRI does not use ionizing radiation (x-rays). ...

Three-dimensional liver motion tracking using real-time two-dimensional MRI.

Science.gov (United States)

Brix, Lau; Ringgaard, Steffen; Sørensen, Thomas Sangild; Poulsen, Per Rugaard

2014-04-01

Combined magnetic resonance imaging (MRI) systems and linear accelerators for radiotherapy (MR-Linacs) are currently under development. MRI is noninvasive and nonionizing and can produce images with high soft tissue contrast. However, new tracking methods are required to obtain fast real-time spatial target localization. This study develops and evaluates a method for tracking three-dimensional (3D) respiratory liver motion in two-dimensional (2D) real-time MRI image series with high temporal and spatial resolution. The proposed method for 3D tracking in 2D real-time MRI series has three steps: (1) Recording of a 3D MRI scan and selection of a blood vessel (or tumor) structure to be tracked in subsequent 2D MRI series. (2) Generation of a library of 2D image templates oriented parallel to the 2D MRI image series by reslicing and resampling the 3D MRI scan. (3) 3D tracking of the selected structure in each real-time 2D image by finding the template and template position that yield the highest normalized cross correlation coefficient with the image. Since the tracked structure has a known 3D position relative to each template, the selection and 2D localization of a specific template translates into quantification of both the through-plane and in-plane position of the structure. As a proof of principle, 3D tracking of liver blood vessel structures was performed in five healthy volunteers in two 5.4 Hz axial, sagittal, and coronal real-time 2D MRI series of 30 s duration. In each 2D MRI series, the 3D localization was carried out twice, using nonoverlapping template libraries, which resulted in a total of 12 estimated 3D trajectories per volunteer. Validation tests carried out to support the tracking algorithm included quantification of the breathing induced 3D liver motion and liver motion directionality for the volunteers, and comparison of 2D MRI estimated positions of a structure in a watermelon with the actual positions. Axial, sagittal, and coronal 2D MRI series

Three-dimensional liver motion tracking using real-time two-dimensional MRI

Energy Technology Data Exchange (ETDEWEB)

Brix, Lau, E-mail: lau.brix@stab.rm.dk [Department of Procurement and Clinical Engineering, Region Midt, Olof Palmes Allé 15, 8200 Aarhus N, Denmark and MR Research Centre, Aarhus University Hospital, Skejby, Brendstrupgaardsvej 100, 8200 Aarhus N (Denmark); Ringgaard, Steffen [MR Research Centre, Aarhus University Hospital, Skejby, Brendstrupgaardsvej 100, 8200 Aarhus N (Denmark); Sørensen, Thomas Sangild [Department of Computer Science, Aarhus University, Aabogade 34, 8200 Aarhus N, Denmark and Department of Clinical Medicine, Aarhus University, Brendstrupgaardsvej 100, 8200 Aarhus N (Denmark); Poulsen, Per Rugaard [Department of Clinical Medicine, Aarhus University, Brendstrupgaardsvej 100, 8200 Aarhus N, Denmark and Department of Oncology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C (Denmark)

2014-04-15

Purpose: Combined magnetic resonance imaging (MRI) systems and linear accelerators for radiotherapy (MR-Linacs) are currently under development. MRI is noninvasive and nonionizing and can produce images with high soft tissue contrast. However, new tracking methods are required to obtain fast real-time spatial target localization. This study develops and evaluates a method for tracking three-dimensional (3D) respiratory liver motion in two-dimensional (2D) real-time MRI image series with high temporal and spatial resolution. Methods: The proposed method for 3D tracking in 2D real-time MRI series has three steps: (1) Recording of a 3D MRI scan and selection of a blood vessel (or tumor) structure to be tracked in subsequent 2D MRI series. (2) Generation of a library of 2D image templates oriented parallel to the 2D MRI image series by reslicing and resampling the 3D MRI scan. (3) 3D tracking of the selected structure in each real-time 2D image by finding the template and template position that yield the highest normalized cross correlation coefficient with the image. Since the tracked structure has a known 3D position relative to each template, the selection and 2D localization of a specific template translates into quantification of both the through-plane and in-plane position of the structure. As a proof of principle, 3D tracking of liver blood vessel structures was performed in five healthy volunteers in two 5.4 Hz axial, sagittal, and coronal real-time 2D MRI series of 30 s duration. In each 2D MRI series, the 3D localization was carried out twice, using nonoverlapping template libraries, which resulted in a total of 12 estimated 3D trajectories per volunteer. Validation tests carried out to support the tracking algorithm included quantification of the breathing induced 3D liver motion and liver motion directionality for the volunteers, and comparison of 2D MRI estimated positions of a structure in a watermelon with the actual positions. Results: Axial, sagittal

Three-dimensional liver motion tracking using real-time two-dimensional MRI

International Nuclear Information System (INIS)

Brix, Lau; Ringgaard, Steffen; Sørensen, Thomas Sangild; Poulsen, Per Rugaard

2014-01-01

Purpose: Combined magnetic resonance imaging (MRI) systems and linear accelerators for radiotherapy (MR-Linacs) are currently under development. MRI is noninvasive and nonionizing and can produce images with high soft tissue contrast. However, new tracking methods are required to obtain fast real-time spatial target localization. This study develops and evaluates a method for tracking three-dimensional (3D) respiratory liver motion in two-dimensional (2D) real-time MRI image series with high temporal and spatial resolution. Methods: The proposed method for 3D tracking in 2D real-time MRI series has three steps: (1) Recording of a 3D MRI scan and selection of a blood vessel (or tumor) structure to be tracked in subsequent 2D MRI series. (2) Generation of a library of 2D image templates oriented parallel to the 2D MRI image series by reslicing and resampling the 3D MRI scan. (3) 3D tracking of the selected structure in each real-time 2D image by finding the template and template position that yield the highest normalized cross correlation coefficient with the image. Since the tracked structure has a known 3D position relative to each template, the selection and 2D localization of a specific template translates into quantification of both the through-plane and in-plane position of the structure. As a proof of principle, 3D tracking of liver blood vessel structures was performed in five healthy volunteers in two 5.4 Hz axial, sagittal, and coronal real-time 2D MRI series of 30 s duration. In each 2D MRI series, the 3D localization was carried out twice, using nonoverlapping template libraries, which resulted in a total of 12 estimated 3D trajectories per volunteer. Validation tests carried out to support the tracking algorithm included quantification of the breathing induced 3D liver motion and liver motion directionality for the volunteers, and comparison of 2D MRI estimated positions of a structure in a watermelon with the actual positions. Results: Axial, sagittal

MRI of the wrist and hand

International Nuclear Information System (INIS)

Reicher, M.A.; Kellerhouse, L.E.

1990-01-01

Magnetic resonance imaging (MRI) is becoming the preferred technique for evaluating a wide range of wrist and hand disorders and has a crucial role in planning arthroscopic and nonarthroscopic wrist surgery. This book details the capabilities of MRI for detecting wrist, hand, and finger pathology; provides a complete understanding of examination techniques, imaging protocols, and anatomy; and contains nearly 400 clear, sharp scans and numerous line drawings showing examination techniques, anatomic structures, and pathologic findings. After an introductory review of MR physics, the book describes state- of-the-art MRI techniques and explains the rationale for selecting imaging protocols. A complete MRI examination of a normal wrist is presented, along with a multiplanar atlas of cross-sectional wrist anatomy

MRI and intraocular tamponade media

Energy Technology Data Exchange (ETDEWEB)

Manfre, I. (Dept. of Neuroradiology, Inst. of Neurosurgery, Univ. of Catania (Italy)); Fabbri, G. (Dept. of Neuroradiology, Inst. of Neurosurgery, Univ. of Catania (Italy)); Avitabile, T. (Inst. of Ophthalmology, Univ. of Catania (Italy)); Biondi, P. (Inst. of Ophthalmology, Univ. of Catania (Italy)); Reibaldi, A. (Inst. of Ophthalmology, Univ. of Catania (Italy)); Pero, G. (Dept. of Neuroradiology, Inst. of Neurosurgery, Univ. of Catania (Italy))

1993-05-01

Thirteen patients who underwent surgery for retinal detachment and injection of intraocular tamponade media (silicone oil, flurosilicone oil, or perfluoro-carbon liquid) underwent magnetic resonance imaging (MRI), using spin-echo T1- and T2-weighted images. The ophthalmic tamponade media showed different signal intensity, according to their chemical structure. Unlike ophthalmoscopy or ultrasonography, MRI showed no oil-related artefact, making possible recognition of recurrent retinal detachment. (orig.)

MRI and intraocular tamponade media

International Nuclear Information System (INIS)

Manfre, I.; Fabbri, G.; Avitabile, T.; Biondi, P.; Reibaldi, A.; Pero, G.

1993-01-01

Thirteen patients who underwent surgery for retinal detachment and injection of intraocular tamponade media (silicone oil, flurosilicone oil, or perfluoro-carbon liquid) underwent magnetic resonance imaging (MRI), using spin-echo T1- and T2-weighted images. The ophthalmic tamponade media showed different signal intensity, according to their chemical structure. Unlike ophthalmoscopy or ultrasonography, MRI showed no oil-related artefact, making possible recognition of recurrent retinal detachment. (orig.)

MRI of the postoperative shoulder

International Nuclear Information System (INIS)

Zlatkin, Michael B.

2002-01-01

Performing and interpreting MRI of the shoulder in patients after surgery is a difficult task. The normal anatomic features are distorted by the surgical alterations as well as the artifacts that result from metal and other materials used in the surgical procedures. This article reviews the common surgical procedures undertaken in patients with rotator cuff disease and shoulder instability, and how they affect the appearance of the relevant anatomic structures on MRI examination. It also reviews the more common causes for residual and recurrent abnormalities seen in such patients and how MRI can be used to diagnose such lesions, thus aiding the orthopedic surgeon in treating these difficult clinical problems. (orig.)

Situs anomalies on prenatal MRI

International Nuclear Information System (INIS)

Nemec, Stefan F.; Brugger, Peter C.; Nemec, Ursula; Bettelheim, Dieter; Kasprian, Gregor; Amann, Gabriele; Rimoin, David L.; Graham, John M.; Prayer, Daniela

2012-01-01

Objective: Situs anomalies refer to an abnormal organ arrangement, which may be associated with severe errors of development. Due regard being given to prenatal magnetic resonance imaging (MRI) as an adjunct to ultrasonography (US), this study sought to demonstrate the in utero visualization of situs anomalies on MRI, compared to US. Materials and methods: This retrospective study included 12 fetuses with situs anomalies depicted on fetal MRI using prenatal US as a comparison modality. With an MRI standard protocol, the whole fetus was assessed for anomalies, with regard to the position and morphology of the following structures: heart; venous drainage and aorta; stomach and intestines; liver and gallbladder; and the presence and number of spleens. Results: Situs inversus totalis was found in 3/12 fetuses; situs inversus with levocardia in 1/12 fetuses; situs inversus abdominis in 2/12 fetuses; situs ambiguous with polysplenia in 3/12 fetuses, and with asplenia in 2/12 fetuses; and isolated dextrocardia in 1/12 fetuses. Congenital heart defects (CHDs), vascular anomalies, and intestinal malrotations were the most frequent associated malformations. In 5/12 cases, the US and MRI diagnoses were concordant. Compared to US, in 7/12 cases, additional MRI findings specified the situs anomaly, but CHDs were only partially visualized in six cases. Conclusions: Our initial MRI results demonstrate the visualization of situs anomalies and associated malformations in utero, which may provide important information for perinatal management. Using a standard protocol, MRI may identify additional findings, compared to US, which confirm and specify the situs anomaly, but, with limited MRI visualization of fetal CHDs.

The search for neuroimaging biomarkers of Alzheimer's disease with advanced MRI techniques

International Nuclear Information System (INIS)

Li, Tie-Qiang; Wahlund, Lars-Olof

2011-01-01

The aim of this review is to examine the recent literature on using advanced magnetic resonance imaging (MRI) techniques for finding neuroimaging biomarkers that are sensitive to the detection of risks for Alzheimer's disease (AD). Since structural MRI techniques, such as brain structural volumetry and voxel based morphometry (VBM), have been widely used for AD studies and extensively reviewed, we will only briefly touch on the topics of volumetry and morphometry. The focus of the current review is about the more recent developments in the search for AD neuroimaging biomarkers with functional MRI (fMRI), resting-state functional connectivity MRI (fcMRI), diffusion tensor imaging (DTI), arterial spin-labeling (ASL), and magnetic resonance spectroscopy (MRS)

Automatic structural parcellation of mouse brain MRI using multi-atlas label fusion.

Directory of Open Access Journals (Sweden)

Da Ma

Full Text Available Multi-atlas segmentation propagation has evolved quickly in recent years, becoming a state-of-the-art methodology for automatic parcellation of structural images. However, few studies have applied these methods to preclinical research. In this study, we present a fully automatic framework for mouse brain MRI structural parcellation using multi-atlas segmentation propagation. The framework adopts the similarity and truth estimation for propagated segmentations (STEPS algorithm, which utilises a locally normalised cross correlation similarity metric for atlas selection and an extended simultaneous truth and performance level estimation (STAPLE framework for multi-label fusion. The segmentation accuracy of the multi-atlas framework was evaluated using publicly available mouse brain atlas databases with pre-segmented manually labelled anatomical structures as the gold standard, and optimised parameters were obtained for the STEPS algorithm in the label fusion to achieve the best segmentation accuracy. We showed that our multi-atlas framework resulted in significantly higher segmentation accuracy compared to single-atlas based segmentation, as well as to the original STAPLE framework.

Recognition of upper airway and surrounding structures at MRI in pediatric PCOS and OSAS

Science.gov (United States)

Tong, Yubing; Udupa, J. K.; Odhner, D.; Sin, Sanghun; Arens, Raanan

2013-03-01

Obstructive Sleep Apnea Syndrome (OSAS) is common in obese children with risk being 4.5 fold compared to normal control subjects. Polycystic Ovary Syndrome (PCOS) has recently been shown to be associated with OSAS that may further lead to significant cardiovascular and neuro-cognitive deficits. We are investigating image-based biomarkers to understand the architectural and dynamic changes in the upper airway and the surrounding hard and soft tissue structures via MRI in obese teenage children to study OSAS. At the previous SPIE conferences, we presented methods underlying Fuzzy Object Models (FOMs) for Automatic Anatomy Recognition (AAR) based on CT images of the thorax and the abdomen. The purpose of this paper is to demonstrate that the AAR approach is applicable to a different body region and image modality combination, namely in the study of upper airway structures via MRI. FOMs were built hierarchically, the smaller sub-objects forming the offspring of larger parent objects. FOMs encode the uncertainty and variability present in the form and relationships among the objects over a study population. Totally 11 basic objects (17 including composite) were modeled. Automatic recognition for the best pose of FOMs in a given image was implemented by using four methods - a one-shot method that does not require search, another three searching methods that include Fisher Linear Discriminate (FLD), a b-scale energy optimization strategy, and optimum threshold recognition method. In all, 30 multi-fold cross validation experiments based on 15 patient MRI data sets were carried out to assess the accuracy of recognition. The results indicate that the objects can be recognized with an average location error of less than 5 mm or 2-3 voxels. Then the iterative relative fuzzy connectedness (IRFC) algorithm was adopted for delineation of the target organs based on the recognized results. The delineation results showed an overall FP and TP volume fraction of 0.02 and 0.93.

DISC1 gene and affective psychopathology: a combined structural and functional MRI study.

Science.gov (United States)

Opmeer, Esther M; van Tol, Marie-José; Kortekaas, Rudie; van der Wee, Nic J A; Woudstra, Saskia; van Buchem, Mark A; Penninx, Brenda W; Veltman, Dick J; Aleman, André

2015-02-01

The gene Disrupted-In-Schizophrenia-1 (DISC1) has been indicated as a determinant of psychopathology, including affective disorders, and shown to influence prefrontal cortex (PFC) and hippocampus functioning, regions of major interest for affective disorders. We aimed to investigate whether DISC1 differentially modulates brain function during executive and memory processing, and morphology in regions relevant for depression and anxiety disorders (affective disorders). 128 participants, with (n = 103) and without (controls; n = 25) affective disorders underwent genotyping for Ser704Cys (with Cys-allele considered as risk-allele) and structural and functional (f) Magnetic Resonance Imaging (MRI) during visuospatial planning and emotional episodic memory tasks. For both voxel-based morphometry and fMRI analyses, we investigated the effect of genotype in controls and explored genotypeXdiagnosis interactions. Results are reported at p < 0.05 FWE small volume corrected. In controls, Cys-carriers showed smaller bilateral (para)hippocampal volumes compared with Ser-homozygotes, and lower activation in the anterior cingulate cortex (ACC) and dorsolateral PFC during visuospatial planning. In anxiety patients, Cys-carriers showed larger (para)hippocampal volumes and more ACC activation during visuospatial planning. In depressive patients, no effect of genotype was observed and overall, no effect of genotype on episodic memory processing was detected. We demonstrated that Ser704Cys-genotype influences (para)hippocampal structure and functioning the dorsal PFC during executive planning, most prominently in unaffected controls. Results suggest that presence of psychopathology moderates Ser704Cys effects. Copyright © 2014 Elsevier Ltd. All rights reserved.

An in vivo MRI template set for morphometry, tissue segmentation and fMRI localization in rats

Directory of Open Access Journals (Sweden)

Pedro Antonio Valdes Hernandez

2011-11-01

Full Text Available Over the last decade, several papers have focused on the construction of highly detailed mouse high field MRI templates via nonlinear registration to unbiased reference spaces, allowing for a variety of neuroimaging applications such as robust morphometric analyses. However, work in rats has only provided medium field MRI averages based on linear registration to biased spaces with the sole purpose of approximate fMRI localization. This precludes any morphometric analysis in spite of the need of exploring in detail the neuroanatomical substrates of diseases in a recent advent of rat models. In this paper we present a new in vivo rat T2 MRI template set, comprising average images of both intensity and shape, obtained via nonlinear registration. Also, unlike previous rat template sets, we include white and gray matter probabilistic segmentations, expanding its use to those applications demanding prior-based tissue segmentation, e.g. SPM voxel-based morphometry. We also provide a preliminary digitalization of latest Paxinos & Watson atlas for anatomical and functional interpretations within the cerebral cortex. We confirmed that, like with previous templates, forepaw and hindpaw fMRI activations can be correctly localized in the expected atlas structure. To exemplify the use of our new MRI template set, we reported the volumes of brain tissues and cortical structures and probed their relationships with ontogenetic development. Other in vivo applications in the near future can be tensor-, deformation- or voxel-based morphometry, morphological connectivity and diffusion tensor-based anatomical connectivity. Our template set, freely available through the SPM extension website, could be an important tool for future longitudinal and/or functional extensive preclinical studies.

MRI-negative temporal lobe epilepsy-What do we know?

Science.gov (United States)

Muhlhofer, Wolfgang; Tan, Yee-Leng; Mueller, Susanne G; Knowlton, Robert

2017-05-01

Temporal lobe epilepsy (TLE) is the most common focal epilepsy in adults. TLE has a high chance of becoming medically refractory, and as such, is frequently considered for further evaluation and surgical intervention. Up to 30% of TLE cases, however, can have normal ("nonlesional" or negative) magnetic resonance imaging (MRI) results, which complicates the presurgical workup and has been associated with worse surgical outcomes. Helped by contributions from advanced imaging techniques and electrical source localization, the number of surgeries performed on MRI-negative TLE has increased over the last decade. Thereby new epidemiologic, clinical, electrophysiologic, neuropathologic, and surgical data of MRI-negative TLE has emerged, showing characteristics that are distinct from those of lesional TLE. This review article summarizes what we know today about MRI-negative TLE, and discusses the comprehensive assessment of patients with MRI-negative TLE in a structured and systematic approach. It also includes a concise description of the most recent developments in structural and functional imaging, and highlights postprocessing imaging techniques that have been shown to add localization value in MRI-negative epilepsies. We evaluate surgical outcomes of MRI-negative TLE, identify prognostic makers of postoperative seizure freedom, and discuss strategies for optimizing the selection of surgical candidates in this group. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

Quantification of structural cerebral abnormalities on MRI 18 months after aneurysmal subarachnoid hemorrhage in patients who received endovascular treatment

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Bresser, Jeroen de [University Medical Center Utrecht, Department of Radiology, P.O. Box 85500, Utrecht (Netherlands); Schaafsma, Joanna D.; Luitse, Merel J.A.; Rinkel, Gabriel J.E.; Biessels, Geert Jan [University Medical Center Utrecht, Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, Utrecht (Netherlands); Viergever, Max A. [University Medical Center Utrecht, Image Sciences Institute, Utrecht (Netherlands)

2015-03-01

Volume measurements performed on brain MRI after aneurysmal subarachnoid hemorrhage (aSAH) may provide insight into the structural abnormalities that underlie the commonly occurring and persistent long-term functional deficits after aSAH. We examined the pattern of long-term cerebral structural changes on MRI in relation to known risk factors for poor functional outcome. We studied MRI scans from 38 patients who received endovascular treatment and were not dependent for activities of daily life at 18 months after aSAH. Risk factors for poor functional outcome (clinical condition, Hijdra score, and bicaudate index on admission; occurrence of hydrocephalus or delayed cerebral infarction during hospitalization) were related to supratentorial cerebral parenchymal and lateral ventricular volumes on MRI with linear regression analyses adjusted for age, sex, and intracranial volume. Clinical condition, Hijdra score, and bicaudate index on admission were not related to cerebral parenchymal volume at 18 months. A higher bicaudate index on admission was related to lateral ventricular enlargement at 18 months after aSAH (Beta; 95%CI: 0.51; 0.14<->0.88). Delayed cerebral infarction was related to smaller cerebral parenchymal volumes (-0.14; -0.25<->-0.04) and to lateral ventricular enlargement (0.49; 0.16<->0.83) at 18 months. Volume measurements of the brain are able to quantify patterns of long-term cerebral damage in relation to different risk factors after aSAH. Application of volumetric techniques may provide more insight into the heterogeneous underlying pathophysiological processes. After confirmation of these results in larger studies, volumetric measures might even be used as outcome measures in future treatment studies. (orig.)

Clinically relevant magnetic resonance imaging (MRI) findings in ...

African Journals Online (AJOL)

Background: Shoulder pain is the most common and well-documented site of musculoskeletal pain in elite swimmers. Structural abnormalities on magnetic resonance imaging (MRI) of elite swimmers' symptomatic shoulders are common. Little has been documented about the association between MRI findings in the ...

Paranasal sinuses and nasopharynx CT and MRI

International Nuclear Information System (INIS)

Sievers, K.W.; Greess, H.; Baum, U.; Dobritz, M.; Lenz, M.

2000-01-01

Neoplastic disease of the nose, paranasal sinuses, the nasopharynx and the parapharyngeal space requires thorough assessment of location and extent in order to plan appropriate treatment. CT allows the deep soft tissue planes to be evaluated and provides a complement to the physical examination. It is especially helpful in regions involving thin bony structures (paranasal sinuses, orbita); here CT performs better than MRI. MRI possesses many advantages over other imaging modalities caused by its excellent tissue contrast. In evaluating regions involving predominantly soft tissue structures (ec nasopharynx and parapharyngeal space) MRI is superior to CT. The possibility to obtain strictly consecutive volume data sets with spiral CT or 3D MRI offer excellent perspectives to visualize the data via 2D or 3D postprocessing. Because head and neck tumors reside in a complex area, having a 3D model of the anatomical features may assist in the delineation of pathology. Data sets may be transferred directly into computer systems and thus be used in computer assisted surgery

Paranasal sinuses and nasopharynx CT and MRI.

Science.gov (United States)

Sievers, K W; Greess, H; Baum, U; Dobritz, M; Lenz, M

2000-03-01

Neoplastic disease of the nose, paranasal sinuses, the nasopharynx and the parapharyngeal space requires thorough assessment of location and extent in order to plan appropriate treatment. CT allows the deep soft tissue planes to be evaluated and provides a complement to the physical examination. It is especially helpful in regions involving thin bony structures (paranasal sinuses, orbita); here CT performs better than MRI. MRI possesses many advantages over other imaging modalities caused by its excellent tissue contrast. In evaluating regions involving predominantly soft tissue structures (ec nasopharynx and parapharyngeal space) MRI is superior to CT. The possibility to obtain strictly consecutive volume data sets with spiral CT or 3D MRI offer excellent perspectives to visualize the data via 2D or 3D postprocessing. Because head and neck tumors reside in a complex area, having a 3D model of the anatomical features may assist in the delineation of pathology. Data sets may be transferred directly into computer systems and thus be used in computer assisted surgery.

MRI of the Chest

Medline Plus

Full Text Available ... you have any devices or metal in your body. Guidelines about eating and drinking before your exam ... soft tissues, bone and virtually all other internal body structures. MRI does not use ionizing radiation (x- ...

MRI of the Chest

Medline Plus

Full Text Available ... to produce detailed pictures of organs, soft tissues, bone and virtually all other internal body structures. MRI ... of the chest. assess disorders of the chest bones (vertebrae, ribs and sternum) and chest wall soft ...

Cine-MRI swallowing evaluation after tongue reconstruction

Energy Technology Data Exchange (ETDEWEB)

Hartl, Dana M. [Department of Otolaryngology-Head and Neck Surgery, Institute Gustave Roussy, 39 rue Camille Desmoulins, 94805 Villejuif Cedex (France)], E-mail: dmhartl@aol.com; Kolb, Frederic; Bretagne, Evelyne [Department of Otolaryngology-Head and Neck Surgery, Institute Gustave Roussy, 39 rue Camille Desmoulins, 94805 Villejuif Cedex (France); Bidault, Francois; Sigal, Robert [Department of Radiology, Institut Gustave Roussy, 39 rue Camille Desmoulins, 94805 Villejuif Cedex (France)

2010-01-15

Objective: To determine the feasibility of cine-MRI for non-invasive swallowing evaluation after surgery for lingual carcinoma with reconstruction using microvascular free flaps. Methods: Ten patients with stage IV carcinoma of the mobile tongue and/or tongue base treated by surgical resection and reconstruction with a free flap were evaluated after an average of 4.3 years (range: 1.5-11 years), using cine-MRI in 'single-shot fast spin echo' (SSFSE) mode. Fiberoptic laryngoscopy of swallowing was performed before MRI to detect aspiration. The tolerance and ability to complete the exam were noted. The mobilities of the oral and pharyngeal structures visualized were evaluated as normal, reduced or increased. Results: Cine-MRI was well tolerated in all cases; 'dry' swallow was performed for the 2 patients with clinical aspiration. Tongue base-pharyngeal wall contact was observed in 5 cases. An increased anterior tongue recoil, increased mandibular recoil, increased posterior oropharyngeal wall advancement and an increased laryngeal elevation were observed in 4 cases. One case of a passive 'slide' mechanism was observed. Conclusions: Cine-MRI is a safe, non-invasive technique for the evaluation of the mobility of oral and oropharyngeal structures after free-flap reconstruction of the tongue. For selected cases, it may be complementary to clinical examination for evaluation of dysphagia after surgery and free-flap reconstruction. Further technical advances will be necessary before cine-MRI can replace videofluoroscopy, however.

Cine-MRI swallowing evaluation after tongue reconstruction

International Nuclear Information System (INIS)

Hartl, Dana M.; Kolb, Frederic; Bretagne, Evelyne; Bidault, Francois; Sigal, Robert

2010-01-01

Objective: To determine the feasibility of cine-MRI for non-invasive swallowing evaluation after surgery for lingual carcinoma with reconstruction using microvascular free flaps. Methods: Ten patients with stage IV carcinoma of the mobile tongue and/or tongue base treated by surgical resection and reconstruction with a free flap were evaluated after an average of 4.3 years (range: 1.5-11 years), using cine-MRI in 'single-shot fast spin echo' (SSFSE) mode. Fiberoptic laryngoscopy of swallowing was performed before MRI to detect aspiration. The tolerance and ability to complete the exam were noted. The mobilities of the oral and pharyngeal structures visualized were evaluated as normal, reduced or increased. Results: Cine-MRI was well tolerated in all cases; 'dry' swallow was performed for the 2 patients with clinical aspiration. Tongue base-pharyngeal wall contact was observed in 5 cases. An increased anterior tongue recoil, increased mandibular recoil, increased posterior oropharyngeal wall advancement and an increased laryngeal elevation were observed in 4 cases. One case of a passive 'slide' mechanism was observed. Conclusions: Cine-MRI is a safe, non-invasive technique for the evaluation of the mobility of oral and oropharyngeal structures after free-flap reconstruction of the tongue. For selected cases, it may be complementary to clinical examination for evaluation of dysphagia after surgery and free-flap reconstruction. Further technical advances will be necessary before cine-MRI can replace videofluoroscopy, however.

A 4-channel 3 Tesla phased array receive coil for awake rhesus monkey fMRI and diffusion MRI experiments.

Science.gov (United States)

Khachaturian, Mark Haig

2010-01-01

Awake monkey fMRI and diffusion MRI combined with conventional neuroscience techniques has the potential to study the structural and functional neural network. The majority of monkey fMRI and diffusion MRI experiments are performed with single coils which suffer from severe EPI distortions which limit resolution. By constructing phased array coils for monkey MRI studies, gains in SNR and anatomical accuracy (i.e., reduction of EPI distortions) can be achieved using parallel imaging. The major challenges associated with constructing phased array coils for monkeys are the variation in head size and space constraints. Here, we apply phased array technology to a 4-channel phased array coil capable of improving the resolution and image quality of full brain awake monkey fMRI and diffusion MRI experiments. The phased array coil is that can adapt to different rhesus monkey head sizes (ages 4-8) and fits in the limited space provided by monkey stereotactic equipment and provides SNR gains in primary visual cortex and anatomical accuracy in conjunction with parallel imaging and improves resolution in fMRI experiments by a factor of 2 (1.25 mm to 1.0 mm isotropic) and diffusion MRI experiments by a factor of 4 (1.5 mm to 0.9 mm isotropic).

MRI of plants and foods

Science.gov (United States)

Van As, Henk; van Duynhoven, John

2013-04-01

The importance and prospects for MRI as applied to intact plants and to foods are presented in view of one of humanity's most pressing concerns, the sustainable and healthy feeding of a worldwide increasing population. Intact plants and foods have in common that their functionality is determined by complex multiple length scale architectures. Intact plants have an additional level of complexity since they are living systems which critically depend on transport and signalling processes between and within tissues and organs. The combination of recent cutting-edge technical advances and integration of MRI accessible parameters has the perspective to contribute to breakthroughs in understanding complex regulatory plant performance mechanisms. In food science and technology MRI allows for quantitative multi-length scale structural assessment of food systems, non-invasive monitoring of heat and mass transport during shelf-life and processing, and for a unique view on food properties under shear. These MRI applications are powerful enablers of rationally (re)designed food formulations and processes. Limitations and bottlenecks of the present plant and food MRI methods are mainly related to short T2 values and susceptibility artefacts originating from small air spaces in tissues/materials. We envisage cross-fertilisation of solutions to overcome these hurdles in MRI applications in plants and foods. For both application areas we witness a development where MRI is moving from highly specialised equipment to mobile and downscaled versions to be used by a broad user base in the field, greenhouse, food laboratory or factory.

MRI in patients with low back pain

DEFF Research Database (Denmark)

Jensen, Rikke Krüger; Manniche, Claus; Leboeuf-Yde, Charlotte

MRI in LBP patients: good or bad? Background: The routine use of radiology is presently discouraged in patients with low back pain (LBP). MRI provides clinicians and patients with detailed knowledge of the spinal structures and has no known physical side effects. It is possible that detailed...... of MRI (the "old" group). As a new approach, all patients with certain criteria are now referred to MRI before the clinical examination (the "new" group).   Objectives: The aims of this study were to investigate if the two different MRI approaches, the "old" and "new", resulted in differences in relation...... to: 1) duration of treatment, 2) number of contacts with clinicians and participation in group exercise, and 3) admission to primary care or another hospital department.   Design: Retrospective inspection of patient files. Method: Files were retrieved from consecutive patients from the "old" and "new...

Distinguishing Adolescents With Conduct Disorder From Typically Developing Youngsters Based on Pattern Classification of Brain Structural MRI

Directory of Open Access Journals (Sweden)

Jianing Zhang

2018-04-01

Full Text Available Background: Conduct disorder (CD is a mental disorder diagnosed in childhood or adolescence that presents antisocial behaviors, and is associated with structural alterations in brain. However, whether these structural alterations can distinguish CD from healthy controls (HCs remains unknown. Here, we quantified these structural differences and explored the classification ability of these quantitative features based on machine learning (ML.Materials and Methods: High-resolution 3D structural magnetic resonance imaging (sMRI was acquired from 60 CD subjects and 60 age-matched HCs. Voxel-based morphometry (VBM was used to assess the regional gray matter (GM volume difference. The significantly different regional GM volumes were then extracted as features, and input into three ML classifiers: logistic regression, random forest and support vector machine (SVM. We trained and tested these ML models for classifying CD from HCs by using fivefold cross-validation (CV.Results: Eight brain regions with abnormal GM volumes were detected, which mainly distributed in the frontal lobe, parietal lobe, anterior cingulate, cerebellum posterior lobe, lingual gyrus, and insula areas. We found that these ML models achieved comparable classification performance, with accuracy of 77.9 ∼ 80.4%, specificity of 73.3 ∼ 80.4%, sensitivity of 75.4 ∼ 87.5%, and area under the receiver operating characteristic curve (AUC of 0.76 ∼ 0.80.Conclusion: Based on sMRI and ML, the regional GM volumes may be used as potential imaging biomarkers for stable and accurate classification of CD.

Clinical investigation on usefulness of MRI in the diagnosis of mediastinal masses

Energy Technology Data Exchange (ETDEWEB)

Oyama, Takao (Kagoshima Univ. (Japan). Faculty of Medicine)

1994-02-01

This study evaluated the utility of magnetic resonance imaging (MRI) in diagnosing mediastinal masses. The subjects were 96 patients with pathologically (n=82) and clinically (n=14) proven mediastinal masses, consisting of thymomas (30), teratomas (4), other thymic tumors (5), intrathoracic goiters (4), neurogenic tumors (7), congenital cysts (12), mesenchymal tumors (10), vascular masses (5), phrenic hernia (3), malignant lymphomas (6), and sarcoidosis (10). MRI findings, including marginal and capsular appearances, internal structures and signal intensities, were analyzed. Internal structure characteristic to thymomas were seen in 24 teratoma patients (80%). In 4 teratomas, MRI was capable of distinguishing benign (2) from malignant (2) ones. In the other 5 thymic tumors, MRI delineated chemical characteristics of fluids for thymic cysts (2) and internal structures for thymic cancer (2) and lipoma (one). It also delineated the continuity of intrathoracic goiter from the cervical to intrathoracic regions. For neurogenic tumors, MRI was capable of distinguishing neurofibromas from schwannomas and also benign from malignant schwannomas. A well-defined smooth margin and very high signal intensity, which were characteristic to congenital cysts, were seen on T2-weighted images. Signal intensities on T1-weighted images reflected fluid features in cysts. For mesenchymal tumors, consisting of hemangioma, hemangiosarcoma, malignant melanoma, aneurysmal bone cyst and osteosarcoma, lymphangioma and chondrosarcoma, all but osteosarcoma showed their respective characteristic MRI findings. Vascular masses were delineated as flow void structures. MRI delineated herniated contents. Malignant lymphoma was shown as irregular and inhomogeneous swollen lymph nodes, but sarcoidosis was shown as regular and homogeneous ones on MRI. In conclusion, MRI is a useful, informative modality for diagnosing mediastinal masses. (N.K.) 84 refs.

Clinical investigation on usefulness of MRI in the diagnosis of mediastinal masses

International Nuclear Information System (INIS)

Oyama, Takao

1994-01-01

This study evaluated the utility of magnetic resonance imaging (MRI) in diagnosing mediastinal masses. The subjects were 96 patients with pathologically (n=82) and clinically (n=14) proven mediastinal masses, consisting of thymomas (30), teratomas (4), other thymic tumors (5), intrathoracic goiters (4), neurogenic tumors (7), congenital cysts (12), mesenchymal tumors (10), vascular masses (5), phrenic hernia (3), malignant lymphomas (6), and sarcoidosis (10). MRI findings, including marginal and capsular appearances, internal structures and signal intensities, were analyzed. Internal structure characteristic to thymomas were seen in 24 teratoma patients (80%). In 4 teratomas, MRI was capable of distinguishing benign (2) from malignant (2) ones. In the other 5 thymic tumors, MRI delineated chemical characteristics of fluids for thymic cysts (2) and internal structures for thymic cancer (2) and lipoma (one). It also delineated the continuity of intrathoracic goiter from the cervical to intrathoracic regions. For neurogenic tumors, MRI was capable of distinguishing neurofibromas from schwannomas and also benign from malignant schwannomas. A well-defined smooth margin and very high signal intensity, which were characteristic to congenital cysts, were seen on T2-weighted images. Signal intensities on T1-weighted images reflected fluid features in cysts. For mesenchymal tumors, consisting of hemangioma, hemangiosarcoma, malignant melanoma, aneurysmal bone cyst and osteosarcoma, lymphangioma and chondrosarcoma, all but osteosarcoma showed their respective characteristic MRI findings. Vascular masses were delineated as flow void structures. MRI delineated herniated contents. Malignant lymphoma was shown as irregular and inhomogeneous swollen lymph nodes, but sarcoidosis was shown as regular and homogeneous ones on MRI. In conclusion, MRI is a useful, informative modality for diagnosing mediastinal masses. (N.K.) 84 refs

SU-E-J-192: Verification of 4D-MRI Internal Target Volume Using Cine MRI

Energy Technology Data Exchange (ETDEWEB)

Lafata, K; Czito, B; Palta, M; Bashir, M; Yin, F; Cai, J [Duke University Medical Center, Durham, NC (United States)

2014-06-01

Purpose: To investigate the accuracy of 4D-MRI in determining the Internal Target Volume (ITV) used in radiation oncology treatment planning of liver cancers. Cine MRI is used as the standard baseline in establishing the feasibility and accuracy of 4D-MRI tumor motion within the liver. Methods: IRB approval was obtained for this retrospective study. Analysis was performed on MR images from four patients receiving external beam radiation therapy for liver cancer at our institution. Eligible patients received both Cine and 4D-MRI scans before treatment. Cine images were acquired sagittally in real time at a slice bisecting the tumor, while 4D images were acquired volumetrically. Cine MR DICOM headers were manipulated such that each respiratory frame was assigned a unique slice location. This approach permitted the treatment planning system (Eclipse, Varian Medical Systems) to recognize a complete respiratory cycle as a “volume”, where the gross tumor was contoured temporally. Software was developed to calculate the union of all frame contours in the structure set, resulting in the corresponding plane of the ITV projecting through the middle of the tumor, defined as the Internal Target Area (ITA). This was repeated for 4D-MRI, at the corresponding slice location, allowing a direct comparison of ITAs obtained from each modality. Results: Four patients have been analyzed. ITAs contoured from 4D-MRI correlate with contours from Cine MRI. The mean error of 4D values relative to Cine values is 7.67 +/− 2.55 %. No single ITA contoured from 4D-MRI demonstrated more than 10.5 % error compared to its Cine MRI counterpart. Conclusion: Motion management is a significant aspect of treatment planning within dynamic environments such as the liver, where diaphragmatic and cardiac activity influence plan accuracy. This small pilot study suggests that 4D-MRI based ITA measurements agree with Cine MRI based measurements, an important step towards clinical implementation. NIH 1R21

SU-E-J-192: Verification of 4D-MRI Internal Target Volume Using Cine MRI

International Nuclear Information System (INIS)

Lafata, K; Czito, B; Palta, M; Bashir, M; Yin, F; Cai, J

2014-01-01

Purpose: To investigate the accuracy of 4D-MRI in determining the Internal Target Volume (ITV) used in radiation oncology treatment planning of liver cancers. Cine MRI is used as the standard baseline in establishing the feasibility and accuracy of 4D-MRI tumor motion within the liver. Methods: IRB approval was obtained for this retrospective study. Analysis was performed on MR images from four patients receiving external beam radiation therapy for liver cancer at our institution. Eligible patients received both Cine and 4D-MRI scans before treatment. Cine images were acquired sagittally in real time at a slice bisecting the tumor, while 4D images were acquired volumetrically. Cine MR DICOM headers were manipulated such that each respiratory frame was assigned a unique slice location. This approach permitted the treatment planning system (Eclipse, Varian Medical Systems) to recognize a complete respiratory cycle as a “volume”, where the gross tumor was contoured temporally. Software was developed to calculate the union of all frame contours in the structure set, resulting in the corresponding plane of the ITV projecting through the middle of the tumor, defined as the Internal Target Area (ITA). This was repeated for 4D-MRI, at the corresponding slice location, allowing a direct comparison of ITAs obtained from each modality. Results: Four patients have been analyzed. ITAs contoured from 4D-MRI correlate with contours from Cine MRI. The mean error of 4D values relative to Cine values is 7.67 +/− 2.55 %. No single ITA contoured from 4D-MRI demonstrated more than 10.5 % error compared to its Cine MRI counterpart. Conclusion: Motion management is a significant aspect of treatment planning within dynamic environments such as the liver, where diaphragmatic and cardiac activity influence plan accuracy. This small pilot study suggests that 4D-MRI based ITA measurements agree with Cine MRI based measurements, an important step towards clinical implementation. NIH 1R21

Assessment of apical periodontitis by MRI. A feasibility study

Energy Technology Data Exchange (ETDEWEB)

Geibel, M.A. [Ulm Univ. (Germany). Oral and Maxillofacial Surgery; Schreiber, E.S.; Bracher, A.K.; Rasche, V. [Ulm Univ. (Germany). Internal Medicine II; Hell, E.; Ulrici, J. [Sirona Dental Systems GmbH, Bensheim (Germany). Dental Imaging; Sailer, L.K. [DOC Praxisklinik im Wiley, Neu-Ulm (Germany). MKG; Ozpeynirci, Y. [Ulm Univ. (Germany). Diagnostic and Interventional Radiology

2015-04-15

The purpose of this clinical feasibility study was to evaluate the applicability of magnetic resonance imaging (MRI) for the assessment of apical periodontitis in direct comparison with cone beam CT (CBCT). 19 consecutive patients (average age 43 ± 13 years) with 34 lesions in total (13 molars, 14 premolars and 7 front teeth) were enrolled in this feasibility study. Periapical lesions were defined as periapical radiolucencies (CBCT) or structural changes in the spongy bone signal (MRI), which were connected with the apical part of a root and with at least twice the width of the periodontal ligament space. The location and dimension of the lesions were compared between MRI and CBCT. While mainly mineralized tissue components such as teeth and bone were visible with CBCT, complimentary information of the soft tissue components was assessable with MRI. The MRI images provided sufficient diagnostic detail for the assessment of the main structures of interest. Heterogeneous contrast was observed within the lesion, with often a clear enhancement close to the apical foramen and the periodontal gap. No difference for lesion visibility was observed between MRI and CBCT. The lesion dimensions corresponded well, but were slightly but significantly overestimated with MRI. A heterogeneous lesion appearance was observed in several patients. Four patients presented with a well circumscribed hyperintense signal in the vicinity of the apical foramen. The MRI capability of soft tissue characterization may facilitate detailed analysis of periapical lesions. This clinical study confirms the applicability of multi-contrast MRI for the identification of periapical lesions.

Assessment of apical periodontitis by MRI. A feasibility study

International Nuclear Information System (INIS)

Geibel, M.A.; Schreiber, E.S.; Bracher, A.K.; Rasche, V.; Hell, E.; Ulrici, J.; Sailer, L.K.; Ozpeynirci, Y.

2015-01-01

The purpose of this clinical feasibility study was to evaluate the applicability of magnetic resonance imaging (MRI) for the assessment of apical periodontitis in direct comparison with cone beam CT (CBCT). 19 consecutive patients (average age 43 ± 13 years) with 34 lesions in total (13 molars, 14 premolars and 7 front teeth) were enrolled in this feasibility study. Periapical lesions were defined as periapical radiolucencies (CBCT) or structural changes in the spongy bone signal (MRI), which were connected with the apical part of a root and with at least twice the width of the periodontal ligament space. The location and dimension of the lesions were compared between MRI and CBCT. While mainly mineralized tissue components such as teeth and bone were visible with CBCT, complimentary information of the soft tissue components was assessable with MRI. The MRI images provided sufficient diagnostic detail for the assessment of the main structures of interest. Heterogeneous contrast was observed within the lesion, with often a clear enhancement close to the apical foramen and the periodontal gap. No difference for lesion visibility was observed between MRI and CBCT. The lesion dimensions corresponded well, but were slightly but significantly overestimated with MRI. A heterogeneous lesion appearance was observed in several patients. Four patients presented with a well circumscribed hyperintense signal in the vicinity of the apical foramen. The MRI capability of soft tissue characterization may facilitate detailed analysis of periapical lesions. This clinical study confirms the applicability of multi-contrast MRI for the identification of periapical lesions.

Structural and functional abnormalities of default mode network in minimal hepatic encephalopathy: a study combining DTI and fMRI.

Directory of Open Access Journals (Sweden)

Rongfeng Qi

Full Text Available BACKGROUND AND PURPOSE: Live failure can cause brain edema and aberrant brain function in cirrhotic patients. In particular, decreased functional connectivity within the brain default-mode network (DMN has been recently reported in overt hepatic encephalopathy (HE patients. However, so far, little is known about the connectivity among the DMN in the minimal HE (MHE, the mildest form of HE. Here, we combined diffusion tensor imaging (DTI and resting-state functional MRI (rs-fMRI to test our hypothesis that both structural and functional connectivity within the DMN were disturbed in MHE. MATERIALS AND METHODS: Twenty MHE patients and 20 healthy controls participated in the study. We explored the changes of structural (path length, tracts count, fractional anisotropy [FA] and mean diffusivity [MD] derived from DTI tractography and functional (temporal correlation coefficient derived from rs-fMRI connectivity of the DMN in MHE patients. Pearson correlation analysis was performed between the structural/functional indices and venous blood ammonia levels/neuropsychological tests scores of patients. All thresholds were set at P<0.05, Bonferroni corrected. RESULTS: Compared to the healthy controls, MHE patients showed both decreased FA and increased MD in the tract connecting the posterior cingulate cortex/precuneus (PCC/PCUN to left parahippocampal gyrus (PHG, and decreased functional connectivity between the PCC/PCUN and left PHG, and medial prefrontal cortex (MPFC. MD values of the tract connecting PCC/PCUN to the left PHG positively correlated to the ammonia levels, the temporal correlation coefficients between the PCC/PCUN and the MPFC showed positive correlation to the digital symbol tests scores of patients. CONCLUSION: MHE patients have both disturbed structural and functional connectivity within the DMN. The decreased functional connectivity was also detected between some regions without abnormal structural connectivity, suggesting that the

Low-Cost High-Performance MRI

Science.gov (United States)

Sarracanie, Mathieu; Lapierre, Cristen D.; Salameh, Najat; Waddington, David E. J.; Witzel, Thomas; Rosen, Matthew S.

2015-10-01

Magnetic Resonance Imaging (MRI) is unparalleled in its ability to visualize anatomical structure and function non-invasively with high spatial and temporal resolution. Yet to overcome the low sensitivity inherent in inductive detection of weakly polarized nuclear spins, the vast majority of clinical MRI scanners employ superconducting magnets producing very high magnetic fields. Commonly found at 1.5-3 tesla (T), these powerful magnets are massive and have very strict infrastructure demands that preclude operation in many environments. MRI scanners are costly to purchase, site, and maintain, with the purchase price approaching $1 M per tesla (T) of magnetic field. We present here a remarkably simple, non-cryogenic approach to high-performance human MRI at ultra-low magnetic field, whereby modern under-sampling strategies are combined with fully-refocused dynamic spin control using steady-state free precession techniques. At 6.5 mT (more than 450 times lower than clinical MRI scanners) we demonstrate (2.5 × 3.5 × 8.5) mm3 imaging resolution in the living human brain using a simple, open-geometry electromagnet, with 3D image acquisition over the entire brain in 6 minutes. We contend that these practical ultra-low magnetic field implementations of MRI (standards for affordable (<$50,000) and robust portable devices.

Hippocampal malrotation: MRI findings

International Nuclear Information System (INIS)

Yanez, Paulina; Martinez, Adriana; Romero, Carlos; Lopez, Miriam; Zaffaroni, Alejandra; Lopez, Adriana

2001-01-01

Purpose: To demonstrate the common features of hippocampus malrotation in patients with epilepsy by volumetric and high-resolution MRI. Material and methods: MRI study was performed in 5 patients (2 females and 3 males) ages ranged between 6-41 years (average: 25 years), all of them with epilepsy diagnosis. MRI was performed with a 1.5 T (GE Signa). The epilepsy protocol include sagittal T1, axial T1 and T2, coronal FLAIR, coronal T2 (high-resolution) and volumetric 3D SPGR IR 1.5 mm thick sequences. Results: The common features found in all patients were: a) Incomplete inversion and round configuration of the hippocampus; b) Unilateral affectation; c) Variable affectation of the hippocampus; d) Normal signal intensity; e) Modification of the inner structure of the hippocampus; f) Abnormal angularity of the collateral sulcus; g) Abnormal position and size of the fornix; h) Normal size of the temporal lobe; and i) Enlargement of the temporal horn with particular configuration. Conclusion: Hippocampus malrotation is a malformation that should be included in the differential diagnosis of the epilepsy patients. MRI provides accurate information for the diagnosis. (author)

Interstitial pregnancy: role of MRI

International Nuclear Information System (INIS)

Filhastre, M.; Lesnik, A.; Dechaud, H.; Taourel, P.

2005-01-01

We report the MRI features of two cases of interstitial pregnancy. In both cases, MRI was able to localize the ectopic pregnancy by showing a gestational structure surrounded by a thick wall in the upper part of the uterine wall separated from the endometrium by an uninterrupted junctional zone. Because US may confuse angular and interstitial pregnancies and because interstitial pregnancy has a particular evolutive course, MR imaging may play a key role in the diagnosis and management of women with interstitial pregnancy. (orig.)

Heart MRI

Science.gov (United States)

Magnetic resonance imaging - cardiac; Magnetic resonance imaging - heart; Nuclear magnetic resonance - cardiac; NMR - cardiac; MRI of the heart; Cardiomyopathy - MRI; Heart failure - MRI; Congenital heart disease - MRI

Fetal MRI: An approach to practice: A review

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Saleem, Sahar N.

2013-01-01

MRI has been increasingly used for detailed visualization of the fetus in utero as well as pregnancy structures. Yet, the familiarity of radiologists and clinicians with fetal MRI is still limited. This article provides a practical approach to fetal MR imaging. Fetal MRI is an interactive scanning of the moving fetus owed to the use of fast sequences. Single-shot fast spin-echo (SSFSE) T2-weighted imaging is a standard sequence. T1-weighted sequences are primarily used to demonstrate fat, cal...

MRI of normal pituitary glands and their surrounding structures

International Nuclear Information System (INIS)

Sato, Yoshiyuki

1991-01-01

Normal MRI appearances of the pituitary glands and their surrounding structures were evaluated in 332 patients without sellar and parasellar diseases. The height of the pituitary gland was maximum at 10-19 years of age reflecting hormonal activity. The width of the pituitary gland decreased, while that of the cavernous sinus increased with aging. This is probably due to atherosclerotic change of the internal carotid artery. Females younger than 30 years of age tended to show a convex upper surface of the pituitary gland and the displacement of the pituitary stalk was common after 50 years of age. Almost all of the anterior lobe of the pituitary gland showed isointensity relative to the pons or cerebral cortex and the majority (85.1%) of the posterior lobe showed hyperintensity. However, the anterior lobe in 2 newborns showed hyperintensity similar to the normal posterior lobe in adults. The posterior lobe was located off the midline in 19.1% of the subjects. One case of pars intermedia cyst was discovered among 14 subjects who were administered Gd-DTPA. The dural membrane between the pituitary gland and cavernous sinus was recognizable only in 8.6% on the right side and 7.5% on the left side. Primary empty sella was identified in 4.5%. Knowledge of the above normal ranges and variations of the pituitary gland and its surrounding structures is important in diagnosing sellar and parasellar lesions. (author) 52 refs

Measurements of brain microstructure and connectivity with diffusion MRI

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Ching-Po Lin

2011-12-01

Full Text Available By probing direction-dependent diffusivity of water molecules, diffusion MRI has shown its capability to reflect the microstructural tissue status and to estimate the neural orientation and pathways in the living brain. This approach has supplied novel insights into in-vivo human brain connections. By detecting the connection patterns, anatomical architecture and structural integrity between cortical regions or subcortical nuclei in the living human brain can be easily identified. It thus opens a new window on brain connectivity studies and disease processes. During the past years, there is a growing interest in exploring the connectivity patterns of the human brain. Specifically, the utilities of noninvasive neuroimaging data and graph theoretical analysis have provided important insights into the anatomical connections and topological pattern of human brain structural networks in vivo. Here, we review the progress of this important technique and the recent methodological and application studies utilizing graph theoretical approaches on brain structural networks with structural MRI and diffusion MRI.

The capability of high field MRI in demonstrating post-mortem fetal brains at different gestational age

International Nuclear Information System (INIS)

Zhang Zhonghe; Liu Shuwei; Lin Xiangtao; Gen Hequn; Teng Gaojun; Fang Fang; Zang Fengchao; Yu Taifei; Zhao Bin

2009-01-01

Objective: To study the capability of high field MRI in demonstrating the post-mortem fetal brains at different gestational age (GA). Methods: One hundred and eight post-mortem fetal brains of 14-40 weeks GA were evaluated by 3.0 T MRI. Eleven brains of 14 to 27 weeks GA with good 3.0 T MRI images were chosen and scanned by 7.0 T MRI. The developing sulci, layered structures of fetal cerebral cortex and basal nuclei were evaluated on MRI of different Tesla (3.0 T and 7.0 T) and their results analyzed. Results: On T 1 WI of 3.0 T MRI, the layered structures of fetal cerebral cortex were present at 14 weeks GA, the sulci were more accurately identified after 16 weeks GA. The basal nuclei were clearly distinguishable after 20 weeks CA, and these structures were better visualized as the GA increased. On T 2 WI of 7.0 T MRI, the sulci, layered structures of fetal cerebral cortex and basal nuclei were shown more clearly at the same GA when compared to 3.0 T, especially the sulci at the early developmental stages. Conclusions: T 1 WI of 3.0 T MRI could show the developing structures of post-mortem fetal brain well, but the T 2 WI of 7.0 T MRI were comparatively better. (authors)

Advances in MRI diagnosis of prostate cancer

International Nuclear Information System (INIS)

Zhang Longmin; Liu Ailian

2014-01-01

Prostate cancer is the second most common cancer in the world, and the incidence of prostate cancer in China shows an upward trend. MRI has high soft tissue resolution and multi-dimensional imaging advantages, and it can better show the anatomy of the prostate and adjacent tissue structures. With the development of MR technique, it plays a more and more important role in prostate cancer diagnosis. This review starts from the imaging performance of routine MRI sequence of prostate cancer, and a variety of functional MRI applications in the diagnosis and differential diagnosis of prostate cancer are described in detail, such as MR perfusion-weighted imaging, MR spectroscopy, MR diffusion-weighted imaging, MR diffusion tensor imaging, intravoxel incoherent motion diffusion-weighted imaging, MR susceptibility-weighted imaging. Meanwhile this review introduces that functional MRI has more advantages and can provide more image information than routine MRI sequence. According to a series of semi-quantitative and quantitative data, functional MRI can further provide the blood perfusion of prostate cancer, water molecule diffusion and microcirculation state, metabolism and biochemical composition change information. (authors)

The search for neuroimaging biomarkers of Alzheimer's disease with advanced MRI techniques

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Li, Tie-Qiang (Karolinska Huddinge - Medical Physics, Stockholm (Sweden)), email: tieqiang.li@karolinska.se; Wahlund, Lars-Olof (Dept. of Neurobiology, Care Sciences and Society, Karolinska Institute, Stockholm (Sweden))

2011-02-15

The aim of this review is to examine the recent literature on using advanced magnetic resonance imaging (MRI) techniques for finding neuroimaging biomarkers that are sensitive to the detection of risks for Alzheimer's disease (AD). Since structural MRI techniques, such as brain structural volumetry and voxel based morphometry (VBM), have been widely used for AD studies and extensively reviewed, we will only briefly touch on the topics of volumetry and morphometry. The focus of the current review is about the more recent developments in the search for AD neuroimaging biomarkers with functional MRI (fMRI), resting-state functional connectivity MRI (fcMRI), diffusion tensor imaging (DTI), arterial spin-labeling (ASL), and magnetic resonance spectroscopy (MRS)

A Novel Marker Based Method to Teeth Alignment in MRI

Science.gov (United States)

Luukinen, Jean-Marc; Aalto, Daniel; Malinen, Jarmo; Niikuni, Naoko; Saunavaara, Jani; Jääsaari, Päivi; Ojalammi, Antti; Parkkola, Riitta; Soukka, Tero; Happonen, Risto-Pekka

2018-04-01

Magnetic resonance imaging (MRI) can precisely capture the anatomy of the vocal tract. However, the crowns of teeth are not visible in standard MRI scans. In this study, a marker-based teeth alignment method is presented and evaluated. Ten patients undergoing orthognathic surgery were enrolled. Supraglottal airways were imaged preoperatively using structural MRI. MRI visible markers were developed, and they were attached to maxillary teeth and corresponding locations on the dental casts. Repeated measurements of intermarker distances in MRI and in a replica model was compared using linear regression analysis. Dental cast MRI and corresponding caliper measurements did not differ significantly. In contrast, the marker locations in vivo differed somewhat from the dental cast measurements likely due to marker placement inaccuracies. The markers were clearly visible in MRI and allowed for dental models to be aligned to head and neck MRI scans.

Structural MRI correlates of cognitive impairment in patients with multiple sclerosis: A Multicenter Study.

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Preziosa, Paolo; Rocca, Maria A; Pagani, Elisabetta; Stromillo, Maria Laura; Enzinger, Christian; Gallo, Antonio; Hulst, Hanneke E; Atzori, Matteo; Pareto, Deborah; Riccitelli, Gianna C; Copetti, Massimiliano; De Stefano, Nicola; Fazekas, Franz; Bisecco, Alvino; Barkhof, Frederik; Yousry, Tarek A; Arévalo, Maria J; Filippi, Massimo

2016-04-01

In a multicenter setting, we applied voxel-based methods to different structural MR imaging modalities to define the relative contributions of focal lesions, normal-appearing white matter (NAWM), and gray matter (GM) damage and their regional distribution to cognitive deficits as well as impairment of specific cognitive domains in multiple sclerosis (MS) patients. Approval of the institutional review boards was obtained, together with written informed consent from all participants. Standardized neuropsychological assessment and conventional, diffusion tensor and volumetric brain MRI sequences were collected from 61 relapsing-remitting MS patients and 61 healthy controls (HC) from seven centers. Patients with ≥2 abnormal tests were considered cognitively impaired (CI). The distribution of focal lesions, GM and WM atrophy, and microstructural WM damage were assessed using voxel-wise approaches. A random forest analysis identified the best imaging predictors of global cognitive impairment and deficits of specific cognitive domains. Twenty-three (38%) MS patients were CI. Compared with cognitively preserved (CP), CI MS patients had GM atrophy of the left thalamus, right hippocampus and parietal regions. They also showed atrophy of several WM tracts, mainly located in posterior brain regions and widespread WM diffusivity abnormalities. WM diffusivity abnormalities in cognitive-relevant WM tracts followed by atrophy of cognitive-relevant GM regions explained global cognitive impairment. Variable patterns of NAWM and GM damage were associated with deficits in selected cognitive domains. Structural, multiparametric, voxel-wise MRI approaches are feasible in a multicenter setting. The combination of different imaging modalities is needed to assess and monitor cognitive impairment in MS. © 2016 Wiley Periodicals, Inc.

Community structure in networks of functional connectivity: resolving functional organization in the rat brain with pharmacological MRI.

Science.gov (United States)

Schwarz, Adam J; Gozzi, Alessandro; Bifone, Angelo

2009-08-01

In the study of functional connectivity, fMRI data can be represented mathematically as a network of nodes and links, where image voxels represent the nodes and the connections between them reflect a degree of correlation or similarity in their response. Here we show that, within this framework, functional imaging data can be partitioned into 'communities' of tightly interconnected voxels corresponding to maximum modularity within the overall network. We evaluated this approach systematically in application to networks constructed from pharmacological MRI (phMRI) of the rat brain in response to acute challenge with three different compounds with distinct mechanisms of action (d-amphetamine, fluoxetine, and nicotine) as well as vehicle (physiological saline). This approach resulted in bilaterally symmetric sub-networks corresponding to meaningful anatomical and functional connectivity pathways consistent with the purported mechanism of action of each drug. Interestingly, common features across all three networks revealed two groups of tightly coupled brain structures that responded as functional units independent of the specific neurotransmitter systems stimulated by the drug challenge, including a network involving the prefrontal cortex and sub-cortical regions extending from the striatum to the amygdala. This finding suggests that each of these networks includes general underlying features of the functional organization of the rat brain.

Role of MRI in the evaluation of ambiguous genitalia

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Secaf, E [Dept. of Radiology, Univ. of California School of Medicine, San Francisco, CA (United States) Dept. de Radiologia, Faculdade de Medicina da Univ. de Sao Paulo (Brazil); Hricak, H [Dept. of Radiology, Univ. of California School of Medicine, San Francisco, CA (United States) Dept. of Urology, Univ. of California School of Medicine, San Francisco, CA (United States); Gooding, C A [Dept. of Radiology, Univ. of California School of Medicine, San Francisco, CA (United States) Dept. of Pediatrics, Univ. of California School of Medicine, San Francisco, CA (United States); Ho, V W [Dept. of Radiology, Univ. of California School of Medicine, San Francisco, CA (United States); Gorczyca, D P [Dept. of Radiology, Univ. of California School of Medicine, San Francisco, CA (United States) Dept. of Radiology, Univ. of California, Los Angeles, CA (United States); Ringertz, H [Dept. of Diagnostic Radiology, Karolinska Hospital, Stockholm (Sweden); Conte, F A [Dept. of Pediatr

1994-08-01

Diagnostic accuracy of magnetic resonance imaging (MRI) interpretation was assessed prospectively in patients with ambiguous genitalia or intersex problems. MRI depiction of the uterus was possible in 93 %, the vagina in 95 %, the penis in 100 %, the testis in 88 %, and the ovary in 74 % of patients. The strength of MRI lies in the multiplanar capability and tissue characterization by means of T1- and T2-weighted sequences. MRI contributes to accurate morphologic evaluation of muellerian duct structures, the gonads, and the development of the phallus, all of which are essential for appropriate gender assignment and planning of surgical reconstruction. (orig.)

Prediction of mechanical properties of trabecular bone using quantitative MRI

International Nuclear Information System (INIS)

Lammentausta, E; Hakulinen, M A; Jurvelin, J S; Nieminen, M T

2006-01-01

Techniques for quantitative magnetic resonance imaging (MRI) have been developed for non-invasive estimation of the mineral density and structure of trabecular bone. The R* 2 relaxation rate (i.e. 1/T* 2 ) is sensitive to bone mineral density (BMD) via susceptibility differences between trabeculae and bone marrow, and by binarizing MRI images, structural variables, such as apparent bone volume fraction, can be assessed. In the present study, trabecular bone samples of human patellae were investigated in vitro at 1.5 T to determine the ability of MRI-derived variables (R* 2 and bone volume fraction) to predict the mechanical properties (Young's modulus, yield stress and ultimate strength). Further, the MRI variables were correlated with reference measurements of volumetric BMD and bone area fraction as determined with a clinical pQCT system. The MRI variables correlated significantly (p 2 and MRI-derived bone volume fraction further improved the prediction of yield stress and ultimate strength. Although pQCT showed a trend towards better prediction of the mechanical properties, current results demonstrate the feasibility of combined MR imaging of marrow susceptibility and bone volume fraction in predicting the mechanical strength of trabecular bone and bone mineral density

Enhancing Diffusion MRI Measures By Integrating Grey and White Matter Morphometry With Hyperbolic Wasserstein Distance

Science.gov (United States)

Zhang, Wen; Shi, Jie; Yu, Jun; Zhan, Liang; Thompson, Paul M.; Wang, Yalin

2017-01-01

In order to improve the preclinical diagnose of Alzheimer's disease (AD), there is a great deal of interest in analyzing the AD related brain structural changes with magnetic resonance image (MRI) analyses. As the major features, variation of the structural connectivity and the cortical surface morphometry provide different views of structural changes to determine whether AD is present on presymptomatic patients. However, the large scale tensor-valued information and relatively low imaging resolution in diffusion MRI (dMRI) have created huge challenges for analysis. In this paper, we propose a novel framework that improves dMRI analysis power by fusing cortical surface morphometry features from structural MRI (sMRI). We first compute the hyperbolic harmonic maps between cortical surfaces with the landmark constraints thus to precisely evaluate surface tensor-based morphometry. Meanwhile, the graph-based analysis of structural connectivity derived from dMRI is conducted. Next, we fuse these two features via the optimal mass transportation (OMT) and eventually the Wasserstein distance (WD) based single image index is computed as a potential clinical multimodality imaging score. We apply our framework to brain images of 20 AD patients and 20 matched healthy controls, randomly chosen from the Alzheimer's Disease Neuroimaging Initiative (AD-NI2) dataset. Our preliminary experimental results of group classification outperformed those of some other single dMRI-based features, such as regional hippocampal volume, mean scores of fractional anisotropy (FA) and mean axial (MD). The novel image fusion pipeline and simple imaging score of structural changes may benefit the preclinical AD and AD prevention research. PMID:28936280

SU-E-J-239: IMRT Planning of Prostate Cancer for a MRI-Linac Based On MRI Only

Energy Technology Data Exchange (ETDEWEB)

Chen, X; Prior, P; Paulson, E; Lawton, C; Li, X [Medical College of Wisconsin, Milwaukee, WI (United States)

2014-06-01

Purpose: : To investigate dosimetric differences between MRI- and CT-based IMRT planning for prostate cancer, the impact of a magnetic field in a MRI-Linac, and to explore the feasibility of IMRT planning based on MRI alone. Methods: IMRT plans were generated based on CT and MRI images acquired on two representative prostate-cancer patients using clinical dose volume constraints. A research planning system (Monaco, Elekta), which employs a Monte Carlo dose engine and includes a perpendicular magnetic field of 1.5T from an MRI-Linac, was used. Bulk electron density assignments based on organ-specific values from ICRU 46 were used to convert MRI (T2) to pseudo CT. With the same beam configuration as in the original CT plan, 5 additional plans were generated based on CT or MRI, with or without optimization (i.e., just recalculation) and with or without the magnetic field. The plan quality in terms of commonly used dose volume (DV) parameters for all plans was compared. The statistical uncertainty on dose was < 1%. Results: For plans with the same contour set but without re-optimization, the DV parameters were different from those for the original CT plan, mostly less than 5% with a few exceptions. These differences were reduced to mostly less than 3% when the plans were re-optimized. For plans with contours from MRI, the differences in the DV parameters varied depending on the difference in the contours as compared to CT. For the optimized plans with contours from MR, the differences for PTV were less than 3%. Conclusion: The prostate IMRT plans based on MRI-only for a MR-Linac were practically similar as compared to the CT plan under the same beam and optimization configuration if the difference on the structure delineation is excluded, indicating the feasibility of using MRI-only for prostate IMRT.

Clinical usefulness of MRI and MRA in children with partial epilepsy; Ocena znaczenia klinicznego obrazowania MRI i MRA w padaczce czesciowej u dzieci

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Zajac, A; Kacinski, M; Kubik, A; Kroczka, S [Klinika Neurologii Dzieciecej, Uniwersytet Jagiellonski, Collegium Medicum, Cracow (Poland)

2006-07-01

Partial epilepsy is a very important problem of epileptology in childhood including clinical and therapeutic aspect especially surgery treatment. The aim of this study is to assess clinical value of neuroimagine techniques (structural MRI, MRI angiography) in partial epilepsy diagnostics in children. The relation between results of examinations with these methods and congenital and acquired risk factors related to partial epilepsy, age of its onset and clinical assessment of patients was analyzed. The study group consisted of 140 children with partial epilepsy hospitalized between 1998 and 2004 in Department of Pediatric Neurology, Collegium Medicum Jagiellonian University, Krakow. The group included 70 girls and 70 boys, the age ranged from 2 months to 17 years. In study group statistical analysis included different factors as which can be related with results of neuroimaging as age, load of pregnancy and birth period, familiar epilepsy, patient's risk factors for appearance of epilepsy, acquired risk factors of epilepsy, results of neurological examination, type of epilepsy, status epilepticus, and signs according epileptic attacks which can be related with neuroimaging results. The primary method of neuroimagine in all patients was structural MRI, in 16 cases Magnetic Resonance Angiography (MRA). The parametric tests (t-student), nonparametric Mann-Whitney's test were used in statistical analysis. The bilateral Fisher test was used to check rate in groups. There was assessed sensitivity, specificity, positive predictive value, negative predictive value; the 95% confidence interval was calculated for these parameters. Abnormalities in neurological examination in children with partial epilepsy were strongly correlated with MRI findings. The structural changes in MRI were found in younger children, whose course of epilepsy was longer than children without MRI changes. Changes in hippocampus ere the most common in children with partial epilepsy with abnormalities in

Dolichoodontoid. A rare cranio-cervical anomaly--MRI findings

International Nuclear Information System (INIS)

Prokesch, Rupert W.; Chocholka, Peter; Bader, Till W.; Ba-Ssalamah, Ahmed; Trattnig, Siegfried

2000-01-01

The case of a 40-year-old woman with a dolichoodontoid, a rare congenital anomaly of the cranio-cervical region, is presented. Due to summation image and overlying bony structures, plain radiographs in two planes were inconclusive. MRI revealed the hyperplasia of the odontoid process, allowed a grading of the subtype of this disorder and demonstrated its relationship to the neural structures within the foramen magnum and the upper cervical spine. Additional inflammatory disease, suspected in this patient with long standing rheumatoid arthritis could be excluded by MRI

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... you have any devices or metal in your body. Guidelines about eating and drinking before your exam ... soft tissues, bone and virtually all other internal body structures. MRI does not use ionizing radiation (x- ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... to produce detailed pictures of organs, soft tissues, bone and virtually all other internal body structures. MRI ... discovery of abnormalities that might be obscured by bone with other imaging methods. The contrast material used ...

MRI after patellofemoral replacement: The preserved compartments

International Nuclear Information System (INIS)

Heyse, Thomas J.; Figiel, Jens; Hähnlein, Ulrike; Timmesfeld, Nina; Lakemeier, Stefan; Schofer, Markus D.; Fuchs-Winkelmann, Susanne; Efe, Turgay

2012-01-01

Introduction: The aim of this study was to assess the reproducibility of magnet resonance imaging (MRI) analysis of preserved anatomic structures of the knee after patellofemoral replacement (PFR). It was hypothesized that evaluation of cartilage, ligaments, meniscus and tendons would result in high inter-observer reliability after PFR. Material and methods: MRI, tailored to reduce metallic artefacts of the knee, after PFR was performed in seven patients. Two independent investigators evaluated cartilage, menisci, collateral and cruciate ligaments, the quadriceps and patellar tendons and the presence of joint effusion. The reviewers used a five-point scale to give a degree of confidence to their evaluation of each parameter. Inter-observer reliability was determined by calculation of Cohen's Kappas. Results: Artefact provoked by the implants was not observed. For all assessed structures, there was excellent inter-observer reliability, with high Cohen's Kappas. There were also high levels of inter-observer agreement and observer confidence in the evaluation of cartilage, meniscus, tendons, ligaments and joint effusion. Conclusion: Tailored MRI allows reproducible analysis of the preserved knee joint structures after PFR. It might prove helpful in assessment of painful knee joints after PFR

MRI after patellofemoral replacement: The preserved compartments

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Heyse, Thomas J., E-mail: heyse@med.uni-marburg.de [Department of Orthopedics and Rheumatology, University Hospital Marburg, Baldingerstrasse, 35043 Marburg (Germany); Figiel, Jens [Department of Radiology, University Hospital Marburg, Marburg (Germany); Hähnlein, Ulrike [Department of Orthopedics and Rheumatology, University Hospital Marburg, Baldingerstrasse, 35043 Marburg (Germany); Timmesfeld, Nina [Institute for Medical Biometry and Epidemiology, Marburg (Germany); Lakemeier, Stefan; Schofer, Markus D.; Fuchs-Winkelmann, Susanne; Efe, Turgay [Department of Orthopedics and Rheumatology, University Hospital Marburg, Baldingerstrasse, 35043 Marburg (Germany)

2012-09-15

Introduction: The aim of this study was to assess the reproducibility of magnet resonance imaging (MRI) analysis of preserved anatomic structures of the knee after patellofemoral replacement (PFR). It was hypothesized that evaluation of cartilage, ligaments, meniscus and tendons would result in high inter-observer reliability after PFR. Material and methods: MRI, tailored to reduce metallic artefacts of the knee, after PFR was performed in seven patients. Two independent investigators evaluated cartilage, menisci, collateral and cruciate ligaments, the quadriceps and patellar tendons and the presence of joint effusion. The reviewers used a five-point scale to give a degree of confidence to their evaluation of each parameter. Inter-observer reliability was determined by calculation of Cohen's Kappas. Results: Artefact provoked by the implants was not observed. For all assessed structures, there was excellent inter-observer reliability, with high Cohen's Kappas. There were also high levels of inter-observer agreement and observer confidence in the evaluation of cartilage, meniscus, tendons, ligaments and joint effusion. Conclusion: Tailored MRI allows reproducible analysis of the preserved knee joint structures after PFR. It might prove helpful in assessment of painful knee joints after PFR.

Cerebral activity mapped by functional MRI

International Nuclear Information System (INIS)

Bruening, R.; Danek, A.; Wu, R.H.; Berchtenbreiter, C.; Reiser, M.

1997-01-01

Functional magnetic resonance imaging (fMRI) is a method to noninvasively measure the changes in cerebral activation during sensitive, cognitive or motor activity. fMRI detects activity by subtraction of states of activity and rest. During activity the signal is increased presumably due to a decrease of deoxyhemoglobin in the capillary and venous structures. Using a full field visual stimulation by flashlight goggles, a signal increase of 3% was detected in the primary visual cortex (V1). Different sequences and postprocessing algorythms will be discussed. Data from the primary cortical areas suggest a high reproducability of the experiments. Successfull experiments highly depend on cooperation of subjects. Despite success in experiments fMRI still has to be established for clinical purposes. (orig.) [de

Structural brain alterations in primary open angle glaucoma: a 3T MRI study

Science.gov (United States)

Wang, Jieqiong; Li, Ting; Sabel, Bernhard A.; Chen, Zhiqiang; Wen, Hongwei; Li, Jianhong; Xie, Xiaobin; Yang, Diya; Chen, Weiwei; Wang, Ningli; Xian, Junfang; He, Huiguang

2016-01-01

Glaucoma is not only an eye disease but is also associated with degeneration of brain structures. We now investigated the pattern of visual and non-visual brain structural changes in 25 primary open angle glaucoma (POAG) patients and 25 age-gender-matched normal controls using T1-weighted imaging. MRI images were subjected to volume-based analysis (VBA) and surface-based analysis (SBA) in the whole brain as well as ROI-based analysis of the lateral geniculate nucleus (LGN), visual cortex (V1/2), amygdala and hippocampus. While VBA showed no significant differences in the gray matter volumes of patients, SBA revealed significantly reduced cortical thickness in the right frontal pole and ROI-based analysis volume shrinkage in LGN bilaterally, right V1 and left amygdala. Structural abnormalities were correlated with clinical parameters in a subset of the patients revealing that the left LGN volume was negatively correlated with bilateral cup-to-disk ratio (CDR), the right LGN volume was positively correlated with the mean deviation of the right visual hemifield, and the right V1 cortical thickness was negatively correlated with the right CDR in glaucoma. These results demonstrate that POAG affects both vision-related structures and non-visual cortical regions. Moreover, alterations of the brain visual structures reflect the clinical severity of glaucoma. PMID:26743811

MRI anatomy of schizophrenia

OpenAIRE

McCarley, Robert William; Wible, Cynthia Gayle; Frumin, Melissa; Hirayasu, Yoshio; Levitt, James Jonathan; Fischer, Iris A.; Shenton, Martha Elizabeth

1999-01-01

Structural magnetic resonance imaging (MRI) data have provided much evidence in support of our current view that schizophrenia is a brain disorder with altered brain structure, and consequently involving more than a simple disturbance in neurotransmission. This review surveys 118 peer–reviewed studies with control group from 1987 to May 1998. Most studies (81%) do not find abnormalities of whole brain/intracranial contents, while lateral ventricle enlargement is reported in 77%, and third ven...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... On very rare occasions, a few patients experience side effects from the contrast material, including nausea, headache and ... structures of the brain and can also provide functional information (fMRI) in selected cases. MR images of ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to evaluate various ... kind, such as an allergy to iodine or x-ray contrast material, drugs, food, or the environment, or ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... other imaging methods. This exam does not use ionizing radiation and may require an injection of a contrast ... other internal body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to ...

Cranial x-ray CT and MRI in congenital muscular dystrophy

International Nuclear Information System (INIS)

Horikawa, Hirosei; Konishi, Toshihiko; Konagaya, Masaaki; Mano, Yukio; Takayanagi, Tetsuya

1988-01-01

The involvements of central nervous system in those cases of congenital muscular dystrophy (CMD), especially in Fukuyama type CMD, have been observed both radiologically and pathologically. The recent development of MRI made it easier to detect fine structural changes in brain matter than the X-ray CT. Then, we tried to evaluate the central nervous system abnormalities of six cases of CMD by both X-ray CT and MRI. In one case, X-ray CT revealed diffuse hypodensity of cerebral white matter, and MRI showed high intensity on long spin-echo image and low intensity on inversion-recovery image. In another case, X-ray CT showed no abnormal findings, but long spin-echo image revealed two high intensity spots in cerebral white matter. In other four cases, brain atrophy was demonstrated by X-ray CT and/or MRI, one case of these patients had bilateral congenital arachnoid cysts in the middle cranial fossa and hypogenesis of temporal lobes. Although we could not demonstrate polymicrogyria and agyria in all cases by MRI, white matter changes and structural changes were revealed more clearly than X-ray CT. The combination of X-ray CT and MRI seems to make a noteworthy contribution to estimate the central nervous system abnormalities in CMD. (author)

MRI and CT in alveolar echinococcosis of the liver

International Nuclear Information System (INIS)

Duewell, S.; Marincek, B.; Schulthess, G.K. von; Ammann, R.; Zurich Univ.

1990-01-01

To compare the value of MRI and CT in evaluating hepatic alveolar echinococcosis a study was conducted on 30 patients. The liver was initially affected in all patients. At the time of examination, 15 patients had undergone partial liver resection. MRI showed no advantage over CT in demonstrating an echinococcal mass lesion. MRI was superior in identifying concomitant pathological changes of the intrahepatic and extrahepatic venous system due to the intrinsic contrast of vascular structures. However, CT was superior in identifying calcifications, an important attribute of the disease. MRI should only be used in imaging alveolar echinococcosis of the liver if diagnostic questions remain open after CT, in particular questions concerning venous pathology. MRI may also be used to replace CT in patients with a contraindication to urographic contrast material. (orig.) [de

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... internal body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to evaluate various ... kind, such as an allergy to iodine or x-ray contrast material, drugs, food, or the environment, or ...

Carbamazepine reduces memory induced activation of mesial temporal lobe structures: a pharmacological fMRI-study

Directory of Open Access Journals (Sweden)

Okujava Michael

2001-11-01

Full Text Available Abstract Background and Purpose It is not known whether carbamazepine (CBZ; a drug widely used in neurology and psychiatry influences the blood oxygenation level dependent (BOLD contrast changes induced by neuronal activation and measured by functional MRI (fMRI. We aimed to investigate the influence of CBZ on memory induced activation of the mesial temporal lobes in patients with symptomatic temporal lobe epilepsy (TLE. Material and Methods Twenty-one individual patients with refractory symptomatic TLE with different CBZ serum levels and 20 healthy controls were studied using BOLD fMRI. Mesial temporal lobe (MTL activation was induced by a task that is based on the retrieval of individually familiar visuo-spatial knowledge. The extent of significant MTL fMRI activation was measured and correlated with the CBZ serum level. Results In TLE patients, the extent of significant fMRI activation over both MTL was negatively correlated to the CBZ serum level (Spearman r = -0.654, P Conclusions In TLE patients, carbamazepine reduces the fMRI-detectable changes within the mesial temporal lobes as induced by effortful memory retrieval. FMRI appears to be suitable to study the effects of chronic drug treatment in patients with epilepsy.

Precuneus atrophy in early-onset Alzheimer's disease: a morphometric structural MRI study

International Nuclear Information System (INIS)

Karas, Giorgos; Scheltens, Philip; Jones, Bethany; Rombouts, Serge; Schijndel, Ronald van; Klein, Martin; Flier, Wiesje van der; Vrenken, Hugo; Barkhof, Frederik

2007-01-01

Alzheimer's disease (AD) usually first presents in elderly patients, but may also develop at an earlier age. Patients with an early age at onset tend to present with complaints other than memory impairment, such as visuospatial problems or apraxia, which may reflect a different distribution of cortical involvement. In this study we set out to investigate whether age at onset in patients with AD determines the pattern of atrophy on cerebral MRI scans. We examined 55 patients with AD over a wide age range and analyzed their 3-D T1-weighted structural MRI scans in standard space using voxel-based morphometry (VBM). Regression analysis was performed to estimate loss of grey matter as a function of age, corrected for mini-mental state examination (MMSE) scores and sex. The VBM analyses identified multiple areas (including the temporal and parietal lobes), showing more atrophy with advancing age. By contrast, a younger age at onset was found to be associated with lower grey matter density in the precuneus. Regionalized volumetric analysis of this region confirmed the existence of disproportionate atrophy in the precuneus in patients with early-onset AD. Application of a multivariate model with precuneus grey matter density as input, showed that precuneal and hippocampal atrophy are independent from each other. Additionally, we found that a smaller precuneus is associated with impaired visuospatial functioning. Our findings support the notion that age at onset modulates the distribution of cortical involvement, and that disproportionate precuneus atrophy is more prominent in patients with a younger age of onset. (orig.)

Gender differences in the structural connectome of the teenage brain revealed by generalized q-sampling MRI

Directory of Open Access Journals (Sweden)

Yeu-Sheng Tyan

2017-01-01

Full Text Available The question of whether there are biological differences between male and female brains is a fraught one, and political positions and prior expectations seem to have a strong influence on the interpretation of scientific data in this field. This question is relevant to issues of gender differences in the prevalence of psychiatric conditions, including autism, attention deficit hyperactivity disorder (ADHD, Tourette's syndrome, schizophrenia, dyslexia, depression, and eating disorders. Understanding how gender influences vulnerability to these conditions is significant. Diffusion magnetic resonance imaging (dMRI provides a non-invasive method to investigate brain microstructure and the integrity of anatomical connectivity. Generalized q-sampling imaging (GQI has been proposed to characterize complicated fiber patterns and distinguish fiber orientations, providing an opportunity for more accurate, higher-order descriptions through the water diffusion process. Therefore, we aimed to investigate differences in the brain's structural network between teenage males and females using GQI. This study included 59 (i.e., 33 males and 26 females age- and education-matched subjects (age range: 13 to 14 years. The structural connectome was obtained by graph theoretical and network-based statistical (NBS analyses. Our findings show that teenage male brains exhibit better intrahemispheric communication, and teenage female brains exhibit better interhemispheric communication. Our results also suggest that the network organization of teenage male brains is more local, more segregated, and more similar to small-world networks than teenage female brains. We conclude that the use of an MRI study with a GQI-based structural connectomic approach like ours presents novel insights into network-based systems of the brain and provides a new piece of the puzzle regarding gender differences.

Gender differences in the structural connectome of the teenage brain revealed by generalized q-sampling MRI.

Science.gov (United States)

Tyan, Yeu-Sheng; Liao, Jan-Ray; Shen, Chao-Yu; Lin, Yu-Chieh; Weng, Jun-Cheng

2017-01-01

The question of whether there are biological differences between male and female brains is a fraught one, and political positions and prior expectations seem to have a strong influence on the interpretation of scientific data in this field. This question is relevant to issues of gender differences in the prevalence of psychiatric conditions, including autism, attention deficit hyperactivity disorder (ADHD), Tourette's syndrome, schizophrenia, dyslexia, depression, and eating disorders. Understanding how gender influences vulnerability to these conditions is significant. Diffusion magnetic resonance imaging (dMRI) provides a non-invasive method to investigate brain microstructure and the integrity of anatomical connectivity. Generalized q-sampling imaging (GQI) has been proposed to characterize complicated fiber patterns and distinguish fiber orientations, providing an opportunity for more accurate, higher-order descriptions through the water diffusion process. Therefore, we aimed to investigate differences in the brain's structural network between teenage males and females using GQI. This study included 59 (i.e., 33 males and 26 females) age- and education-matched subjects (age range: 13 to 14 years). The structural connectome was obtained by graph theoretical and network-based statistical (NBS) analyses. Our findings show that teenage male brains exhibit better intrahemispheric communication, and teenage female brains exhibit better interhemispheric communication. Our results also suggest that the network organization of teenage male brains is more local, more segregated, and more similar to small-world networks than teenage female brains. We conclude that the use of an MRI study with a GQI-based structural connectomic approach like ours presents novel insights into network-based systems of the brain and provides a new piece of the puzzle regarding gender differences.

The impact of MRI on the clinical management of inflammatory arthritides

Energy Technology Data Exchange (ETDEWEB)

Weber, Ulrich [University of Alberta, Department of Medicine, Division of Rheumatology, Edmonton, AB (Canada); Balgrist University Hospital, Department of Rheumatology, Zurich (Switzerland); Oestergaard, Mikkel [Copenhagen University Hospital at Glostrup, Department of Rheumatology, Copenhagen (Denmark); Lambert, Robert G.W. [University of Alberta, Department of Radiology and Diagnostic Imaging, Edmonton, AB (Canada); Maksymowych, Walter P. [University of Alberta, Department of Medicine, Division of Rheumatology, Edmonton, AB (Canada)

2011-09-15

In the past two decades, MRI has gained a major role in research and clinical management of patients with inflammatory arthritides, particularly in spondyloarthritis (SpA), rheumatoid arthritis (RA), and osteoarthritis (OA). MRI is regarded as the most sensitive imaging modality for detecting early SpA in young patients with inflammatory back pain and normal radiographs of the sacroiliac joints. The recently published Assessment of SpondyloArthritis International Society classification criteria for axial SpA include for the first time a positive MRI demonstrating sacroiliitis as an imaging criterion indicative of SpA together with at least one clinical feature of SpA. Recent data show that systematic assessment of sacroiliitis displayed on MRI has much greater diagnostic utility than previously reported and highlight the diagnostic relevance of structural lesions. In RA, MRI has predictive value for the development of disease in new onset undifferentiated arthritis, and MR pathology at disease onset is a highly significant predictor of radiographic erosions. Consequently MRI has been credited with an important role in the new ACR/EULAR 2010 classification criteria for RA. In OA, bone marrow edema (BME) and synovitis may serve as biomarkers in interventional trials. Treatment interventions targeting BME and synovitis observed on MRI in inflammatory arthritides may have a disease-modifying effect as these lesions are potentially reversible and have been shown to be associated with structural progression. Research should focus on the prognostic significance of MRI lesions in larger cohorts and whether adding MRI to routine care improves clinical and radiographic outcome in patients with inflammatory arthritides. (orig.)

Motor function deficits in schizophrenia: an fMRI and VBM study

Energy Technology Data Exchange (ETDEWEB)

Singh, Sadhana; Modi, Shilpi; Kumar, Pawan; Singh, Namita; Khushu, Subash [Institute of Nuclear Medicine and Allied Sciences (INMAS), NMR Research Center, Delhi (India); Goyal, Satnam; Bhatia, Triptish; Deshpande, Smita N. [RML Hospital, PGIMER, New Delhi (India)

2014-05-15

To investigate whether the motor functional alterations in schizophrenia (SZ) are also associated with structural changes in the related brain areas using functional magnetic resonance imaging (fMRI) and voxel-based morphometry (VBM). A sample of 14 right-handed SZ patients and 14 right-handed healthy control subjects matched for age, sex, and education were examined with structural high-resolution T1-weighted MRI; fMRI images were obtained during right index finger-tapping task in the same session. fMRI results showed reduced functional activation in the motor areas (contralateral precentral and postcentral gyrus) and ipsilateral cerebellum in SZ subjects as compared to healthy controls (n = 14). VBM analysis also revealed reduced grey matter in motor areas and white matter reduction in cerebellum of SZ subjects as compared to controls. The present study provides an evidence for a possible association between structural alterations in the motor cortex and disturbed functional activation in the motor areas in persons affected with SZ during a simple finger-tapping task. (orig.)

Motor function deficits in schizophrenia: an fMRI and VBM study

International Nuclear Information System (INIS)

Singh, Sadhana; Modi, Shilpi; Kumar, Pawan; Singh, Namita; Khushu, Subash; Goyal, Satnam; Bhatia, Triptish; Deshpande, Smita N.

2014-01-01

To investigate whether the motor functional alterations in schizophrenia (SZ) are also associated with structural changes in the related brain areas using functional magnetic resonance imaging (fMRI) and voxel-based morphometry (VBM). A sample of 14 right-handed SZ patients and 14 right-handed healthy control subjects matched for age, sex, and education were examined with structural high-resolution T1-weighted MRI; fMRI images were obtained during right index finger-tapping task in the same session. fMRI results showed reduced functional activation in the motor areas (contralateral precentral and postcentral gyrus) and ipsilateral cerebellum in SZ subjects as compared to healthy controls (n = 14). VBM analysis also revealed reduced grey matter in motor areas and white matter reduction in cerebellum of SZ subjects as compared to controls. The present study provides an evidence for a possible association between structural alterations in the motor cortex and disturbed functional activation in the motor areas in persons affected with SZ during a simple finger-tapping task. (orig.)

FDG whole-body PET/MRI in oncology: A systematic review

Energy Technology Data Exchange (ETDEWEB)

Kwon, Hyun Woo [Dept. of Nuclear Medicine, Soonchunhyang University Hospital, Cheonan (Korea, Republic of); Becker, Ann-Katharina [Rheinisch Westfalische Technische Hochschule Aachen University, Aachen (Germany); Goo, Jin Mo; Cheon, Gi Jeong [Seoul National University, College of Medicine,Seoul (Korea, Republic of)

2017-03-15

The recent advance in hybrid imaging techniques enables offering simultaneous positron emission tomography (PET)/magnetic resonance imaging (MRI) in various clinical fields. 18F-fluorodeoxyglucose (FDG) PET has been widely used for diagnosis and evaluation of oncologic patients. The growing evidence from research and clinical experiences demonstrated that PET/MRI with FDG can provide comparable or superior diagnostic performance more than conventional radiological imaging such as computed tomography (CT), MRI or PET/CT in various cancers. Combined analysis using structural information and functional/molecular information of tumors can draw additional diagnostic information based on PET/MRI. Further studies including determination of the diagnostic efficacy, optimizing the examination protocol, and analysis of the hybrid imaging results is necessary for extending the FDG PET/MRI application in clinical oncology.

MRI Overestimates Excitotoxic Amygdala Lesion Damage in Rhesus Monkeys

Directory of Open Access Journals (Sweden)

Benjamin M. Basile

2017-06-01

Full Text Available Selective, fiber-sparing excitotoxic lesions are a state-of-the-art tool for determining the causal contributions of different brain areas to behavior. For nonhuman primates especially, it is advantageous to keep subjects with high-quality lesions alive and contributing to science for many years. However, this requires the ability to estimate lesion extent accurately. Previous research has shown that in vivo T2-weighted magnetic resonance imaging (MRI accurately estimates damage following selective ibotenic acid lesions of the hippocampus. Here, we show that the same does not apply to lesions of the amygdala. Across 19 hemispheres from 13 rhesus monkeys, MRI assessment consistently overestimated amygdala damage as assessed by microscopic examination of Nissl-stained histological material. Two outliers suggested a linear relation for lower damage levels, and values of unintended amygdala damage from a previous study fell directly on that regression line, demonstrating that T2 hypersignal accurately predicts damage levels below 50%. For unintended damage, MRI estimates correlated with histological assessment for entorhinal cortex, perirhinal cortex and hippocampus, though MRI significantly overestimated the extent of that damage in all structures. Nevertheless, ibotenic acid injections routinely produced extensive intentional amygdala damage with minimal unintended damage to surrounding structures, validating the general success of the technique. The field will benefit from more research into in vivo lesion assessment techniques, and additional evaluation of the accuracy of MRI assessment in different brain areas. For now, in vivo MRI assessment of ibotenic acid lesions of the amygdala can be used to confirm successful injections, but MRI estimates of lesion extent should be interpreted with caution.

Clinical application of functional MRI for chronic epilepsy

International Nuclear Information System (INIS)

Woermann, F.G.; Labudda, K.

2010-01-01

Functional magnetic resonance imaging (fMRI) is frequently used in the presurgical diagnostic procedure of epilepsy patients, in particular for lateralization of speech and memory and for localization of the primary motor cortex to delineate the epileptogenic lesion from eloquent brain areas. fMRI is one of the non-invasive procedures in the presurgical diagnostic process, together with medical history, seizure semiology, neurological examination, interictal and ictal EEG, structural MRI, video EEG monitoring and neuropsychology. This diagnostic sequence leads either to the decision for or against elective epilepsy surgery or to the decision to proceed with invasive diagnostic techniques (Wada test, intra-operative or extra-operative cortical stimulation). It is difficult to evaluate the contribution of the fMRI test in isolation to the validity of the entire diagnostic sequence. Complications such as memory loss and aphasia in temporal lobe resections or paresis after frontal lobe resections are rare and rarely of disastrous extent. This further complicates the evaluation of the clinical relevance of fMRI as a predictive tool. In this article studies which investigated the concordance between fMRI and other diagnostic gold standards will be presented as well as the association between presurgical fMRI and postsurgical morbidity. (orig.) [de

A Technique for Generating Volumetric Cine MRI (VC-MRI)

Science.gov (United States)

Harris, Wendy; Ren, Lei; Cai, Jing; Zhang, You; Chang, Zheng; Yin, Fang-Fang

2016-01-01

Purpose To develop a technique to generate on-board volumetric-cine MRI (VC-MRI) using patient prior images, motion modeling and on-board 2D-cine MRI. Methods One phase of a 4D-MRI acquired during patient simulation is used as patient prior images. 3 major respiratory deformation patterns of the patient are extracted from 4D-MRI based on principal-component-analysis. The on-board VC-MRI at any instant is considered as a deformation of the prior MRI. The deformation field is represented as a linear combination of the 3 major deformation patterns. The coefficients of the deformation patterns are solved by the data fidelity constraint using the acquired on-board single 2D-cine MRI. The method was evaluated using both XCAT simulation of lung cancer patients and MRI data from four real liver cancer patients. The accuracy of the estimated VC-MRI was quantitatively evaluated using Volume-Percent-Difference(VPD), Center-of-Mass-Shift(COMS), and target tracking errors. Effects of acquisition orientation, region-of-interest(ROI) selection, patient breathing pattern change and noise on the estimation accuracy were also evaluated. Results Image subtraction of ground-truth with estimated on-board VC-MRI shows fewer differences than image subtraction of ground-truth with prior image. Agreement between profiles in the estimated and ground-truth VC-MRI was achieved with less than 6% error for both XCAT and patient data. Among all XCAT scenarios, the VPD between ground-truth and estimated lesion volumes was on average 8.43±1.52% and the COMS was on average 0.93±0.58mm across all time-steps for estimation based on the ROI region in the sagittal cine images. Matching to ROI in the sagittal view achieved better accuracy when there was substantial breathing pattern change. The technique was robust against noise levels up to SNR=20. For patient data, average tracking errors were less than 2 mm in all directions for all patients. Conclusions Preliminary studies demonstrated the

MRI Primer

International Nuclear Information System (INIS)

Oldendorf, W.; Oldendorf, W. Jr.

1991-01-01

Designed for studies, radiologists, and clinicians at all levels of training, this book provides a basic introduction to the principles, physics, and instrumentation of magnetic resonance imaging. The fundamental concepts that are essential for the optimal clinical use of MRI are thoroughly explained in easily accessible terms. To facilitate the reader's comprehension, the material is presented nonmathematically, using no equations and a minimum of symbols and abbreviations. MRI Primer presents a clear account of the phenomenon of nuclear magnetic resonance and the use of gradient magnetic fields to create clinically useful images of cross-sectional slices. Close attention is given to the magnetization vector as a means of expressing nuclear behavior, the role of T 1 and T 2 weighing in imaging, the use of contrast agents, and the pulse sequences most often used in clinical practice, as well as to the relative capabilities and limitations of MRI and CT. The basic hardware components of an MRI scanner are described in detail. Sample MRI scans illustrate how MRI characterizes tissue. An appendix provides a brief introduction to quantum processes in MRI

Breast MRI: EUSOBI recommendations for women's information

International Nuclear Information System (INIS)

Mann, Ritse M.; Balleyguier, Corinne; Baltzer, Pascal A.; Helbich, Thomas H.; Pinker-Domenig, Katja; Bick, Ulrich; Fallenberg, Eva; Colin, Catherine; Cornford, Eleanor; Evans, Andrew; Forrai, Gabor; Fuchsjaeger, Michael H.; Gilbert, Fiona J.; Heywang-Koebrunner, Sylvia H.; Camps-Herrero, Julia; Kuhl, Christiane K.; Martincich, Laura; Pediconi, Federica; Panizza, Pietro; Pina, Luis J.; Pijnappel, Ruud M.; Skaane, Per; Sardanelli, Francesco

2015-01-01

This paper summarizes information about breast MRI to be provided to women and referring physicians. After listing contraindications, procedure details are described, stressing the need for correct scheduling and not moving during the examination. The structured report including BI-RADS registered categories and further actions after a breast MRI examination are discussed. Breast MRI is a very sensitive modality, significantly improving screening in high-risk women. It also has a role in clinical diagnosis, problem solving, and staging, impacting on patient management. However, it is not a perfect test, and occasionally breast cancers can be missed. Therefore, clinical and other imaging findings (from mammography/ultrasound) should also be considered. Conversely, MRI may detect lesions not visible on other imaging modalities turning out to be benign (false positives). These risks should be discussed with women before a breast MRI is requested/performed. Because breast MRI drawbacks depend upon the indication for the examination, basic information for the most important breast MRI indications is presented. Seventeen notes and five frequently asked questions formulated for use as direct communication to women are provided. The text was reviewed by Europa Donna-The European Breast Cancer Coalition to ensure that it can be easily understood by women undergoing MRI. (orig.)

Breast MRI: EUSOBI recommendations for women's information

Energy Technology Data Exchange (ETDEWEB)

Mann, Ritse M. [Radboud University Nijmegen Medical Centre, Department of Radiology, Nijmegen (Netherlands); Balleyguier, Corinne [Gustave-Roussy Institute, Department of Radiology, Villejuif (France); Baltzer, Pascal A.; Helbich, Thomas H.; Pinker-Domenig, Katja [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Vienna (Austria); Bick, Ulrich; Fallenberg, Eva [Universitaetsmedizin Berlin, Clinic of Radiology, Charite, Berlin (Germany); Colin, Catherine [Centre Hospitalo-Universitaire Lyon Sud, Radiology Unit, Hospices Civils de Lyon, Pierre Benite Cedex (France); Cornford, Eleanor [Nottingham University Hospitals, Nottingham Breast Institute, Nottingham (United Kingdom); Evans, Andrew [Ninewells Hospital and Medical School, Dundee Cancer Centre, Clinical Research Centre, Dundee (United Kingdom); Forrai, Gabor [MHEK Teaching Hospital University Semmelweis, Budapest (Hungary); Fuchsjaeger, Michael H. [Medical University of Graz, Department of Radiology, Graz (Austria); Gilbert, Fiona J. [University of Cambridge, School of Clinical Medicine, Department of Radiology, Cambridge (United Kingdom); Heywang-Koebrunner, Sylvia H. [National Reference Centre Mammography, Munich, Munich (Germany); Camps-Herrero, Julia [Hospital de la Ribera, Department of Radiology, Alzira, Valencia (Spain); Kuhl, Christiane K. [University Hospital of Aachen, Rheinisch-Westfaelische Technische Hochschule, Aachen (Germany); Martincich, Laura [IRCCS-FPO, Radiology Unit, Candiolo, Turin (Italy); Pediconi, Federica [Sapienza University, Department of Radiological, Oncological and Pathological Sciences, Rome (Italy); Panizza, Pietro [Fondazione IRCCS Istituto Nazionale dei Tumori, Department of Radiology 1, Milan (Italy); Pina, Luis J. [Clinica Universidad de Navarra, Department of Radiology, Pamplona, Navarra (Spain); Pijnappel, Ruud M. [University Medical Centre Utrecht, Department of Imaging, Utrecht (Netherlands); Skaane, Per [Oslo University Hospital Ullevaal, University of Oslo, Department of Radiology, Oslo (Norway); Sardanelli, Francesco [Universita degli Studi di Milano, Radiology Unit, IRCCS Policlinico San Donato, Department of Biomedical Sciences for Health, San Donato Milanese, Milan (Italy); Collaboration: for the European Society of Breast Imaging (EUSOBI), with language review by Europa Donna-The European Breast Cancer Coalition

2015-12-15

This paper summarizes information about breast MRI to be provided to women and referring physicians. After listing contraindications, procedure details are described, stressing the need for correct scheduling and not moving during the examination. The structured report including BI-RADS registered categories and further actions after a breast MRI examination are discussed. Breast MRI is a very sensitive modality, significantly improving screening in high-risk women. It also has a role in clinical diagnosis, problem solving, and staging, impacting on patient management. However, it is not a perfect test, and occasionally breast cancers can be missed. Therefore, clinical and other imaging findings (from mammography/ultrasound) should also be considered. Conversely, MRI may detect lesions not visible on other imaging modalities turning out to be benign (false positives). These risks should be discussed with women before a breast MRI is requested/performed. Because breast MRI drawbacks depend upon the indication for the examination, basic information for the most important breast MRI indications is presented. Seventeen notes and five frequently asked questions formulated for use as direct communication to women are provided. The text was reviewed by Europa Donna-The European Breast Cancer Coalition to ensure that it can be easily understood by women undergoing MRI. (orig.)

Structural hippocampal network alterations during healthy aging: A multi-modal MRI study

Directory of Open Access Journals (Sweden)

Amandine ePelletier

2013-12-01

Full Text Available While hippocampal atrophy has been described during healthy aging, few studies have examined its relationship with the integrity of White Matter (WM connecting tracts of the limbic system. This investigation examined WM structural damage specifically related to hippocampal atrophy in healthy aging subjects (n=129, using morphological MRI to assess hippocampal volume and Diffusion Tensor Imaging (DTI to assess WM integrity. Subjects with Mild Cognitive Impairment (MCI or dementia were excluded from the analysis. In our sample, increasing age was significantly associated with reduced hippocampal volume and reduced Fractional Anisotropy (FA at the level of the fornix and the cingulum bundle. The findings also demonstrate that hippocampal atrophy was specifically associated with reduced FA of the fornix bundle, but it was not related to alteration of the cingulum bundle. Our results indicate that the relationship between hippocampal atrophy and fornix FA values is not due to an independent effect of age on both structures. A recursive regression procedure was applied to evaluate sequential relationships between the alterations of these two brain structures. When both hippocampal atrophy and fornix FA values were included in the same model to predict age, fornix FA values remained significant whereas hippocampal atrophy was no longer significantly associated with age. According to this latter finding, hippocampal atrophy in healthy aging could be mediated by a loss of fornix connections. Structural alterations of this part of the limbic system, which have been associated with neurodegeneration in Alzheimer’s disease, result at least in part from the aging process.

Simultaneous MRI and PET imaging of a rat brain

Energy Technology Data Exchange (ETDEWEB)

Raylman, Raymond R [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States); Majewski, Stan [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Lemieux, Susan K [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States); Velan, S Sendhil [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States); Kross, Brian [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Popov, Vladimir [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Smith, Mark F [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Weisenberger, Andrew G [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Zorn, Carl [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Marano, Gary D [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States)

2006-12-21

Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI will allow the correlation of form with function. Our group is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode. Each MRI-PET detector module consists of an array of LSO detector elements coupled through a long fibre optic light guide to a single Hamamatsu flat panel position-sensitive photomultiplier tube (PSPMT). The use of light guides allows the PSPMTs to be positioned outside the bore of a 3T MRI scanner where the magnetic field is relatively small. To test the device, simultaneous MRI and PET images of the brain of a male Sprague Dawley rat injected with FDG were successfully obtained. The images revealed no noticeable artefacts in either image set. Future work includes the construction of a full ring PET scanner, improved light guides and construction of a specialized MRI coil to permit higher quality MRI imaging.

Simultaneous MRI and PET imaging of a rat brain

International Nuclear Information System (INIS)

Raylman, Raymond R; Majewski, Stan; Lemieux, Susan K; Velan, S Sendhil; Kross, Brian; Popov, Vladimir; Smith, Mark F; Weisenberger, Andrew G; Zorn, Carl; Marano, Gary D

2006-01-01

Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI will allow the correlation of form with function. Our group is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode. Each MRI-PET detector module consists of an array of LSO detector elements coupled through a long fibre optic light guide to a single Hamamatsu flat panel position-sensitive photomultiplier tube (PSPMT). The use of light guides allows the PSPMTs to be positioned outside the bore of a 3T MRI scanner where the magnetic field is relatively small. To test the device, simultaneous MRI and PET images of the brain of a male Sprague Dawley rat injected with FDG were successfully obtained. The images revealed no noticeable artefacts in either image set. Future work includes the construction of a full ring PET scanner, improved light guides and construction of a specialized MRI coil to permit higher quality MRI imaging

Optimal structure of particles-based superparamagnetic microrobots: application to MRI guided targeted drug therapy

International Nuclear Information System (INIS)

Mellal, Lyès; Belharet, Karim; Folio, David; Ferreira, Antoine

2015-01-01

This paper presents an optimal design strategy for therapeutic magnetic micro carriers (TMMC) guided in real time by a magnetic resonance imaging (MRI) system. As aggregates of TMMCs must be formed to carry the most amount of drug and magnetic actuation capability, different clustering agglomerations could be arranged. Nevertheless, its difficult to predict the hydrodynamic behavior of any arbitrary-shaped object due to the nonlinear hydrodynamic effects. Indeed, the drag effect is related not only to the properties of the bolus but also to its interaction with the fluid viscosity, the free-stream velocity and the container geometry. In this work, we propose a mathematical framework to optimize the TMMC aggregates to improve the steering efficiency in experimental endovascular conditions. The proposed analysis is carried out on various sizes and geometries of microcarrier: spherical, ellipsoid-like, and chain-like of microsphere structures. We analyze the magnetophoretic behavior of such designs to exhibit the optimal configuration. Based on the optimal design of the boluses, experimental investigations were carried out in mm-sized fluidic artery phantoms to demonstrate the steerability of the magnetic bolus using a proof-of-concept setup. The experiments demonstrate the steerability of the magnetic bolus under different velocity, shear-stress, and trajectory constraints with a laminar viscous fluidic environment. Preliminary experiments with a MRI system confirm the feasibility of the steering of these TMMCs in hepatic artery microchannel phantom

Multi-center MRI prediction models : Predicting sex and illness course in first episode psychosis patients

OpenAIRE

Nieuwenhuis, Mireille; Schnack, Hugo G.; van Haren, Neeltje E.; Kahn, René S.; Lappin, Julia; Dazzan, Paola; Morgan, Craig; Reinders, Antje A.; Gutierrez-Tordesillas, Diana; Gutierrez-Tordesillas, Diana; Roiz-Santiañez, Roberto; Crespo-Facorro, Benedicto; Schaufelberger, Maristela S.; Rosa, Pedro G.; Zanetti, Marcus V.

2017-01-01

Structural Magnetic Resonance Imaging (MRI) studies have attempted to use brain measures obtained at the first-episode of psychosis to predict subsequent outcome, with inconsistent results. Thus, there is a real need to validate the utility of brain measures in the prediction of outcome using large datasets, from independent samples, obtained with different protocols and from different MRI scanners. This study had three main aims: 1) to investigate whether structural MRI data from multiple ce...

Multi-center MRI prediction models:Predicting sex and illness course in first episode psychosis patients

OpenAIRE

Nieuwenhuis, Mireille; Schnack, Hugo G; van Haren, Neeltje E; Lappin, Julia; Morgan, Craig; Reinders, Antje A; Gutierrez-Tordesillas, Diana; Roiz-Santiañez, Roberto; Schaufelberger, Maristela S; Rosa, Pedro G; Zanetti, Marcus V; Busatto, Geraldo F; Crespo-Facorro, Benedicto; McGorry, Patrick D; Velakoulis, Dennis

2017-01-01

Structural Magnetic Resonance Imaging (MRI) studies have attempted to use brain measures obtained at the first-episode of psychosis to predict subsequent outcome, with inconsistent results. Thus, there is a real need to validate the utility of brain measures in the prediction of outcome using large datasets, from independent samples, obtained with different protocols and from different MRI scanners. This study had three main aims: 1) to investigate whether structural MRI data from multiple ce...

Spica MRI after closed reduction for developmental dysplasia of the hip

Energy Technology Data Exchange (ETDEWEB)

Desai, Aditi A. [Vanderbilt University School of Medicine, Nashville, TN (United States); Martus, Jeffrey E.; Schoenecker, Jon [Vanderbilt University School of Medicine, Department of Orthopaedics and Rehabilitation, Monroe Carroll Jr. Children' s Hospital at Vanderbilt, Nashville, TN (United States); Kan, J.H. [Vanderbilt University School of Medicine, Department of Radiology and Radiological Sciences, Monroe Carroll Jr. Children' s Hospital at Vanderbilt, Nashville, TN (United States)

2011-04-15

Spica MRI is a fast and effective tool to assess morphology after closed reduction for developmental dysplasia of the hip (DDH) without the need for sedation. The multiplanar capabilities allow depiction of coronal and axial reduction of the hips. Due to MRI's inherent ability to delineate soft tissue structures, both intrinsic and extrinsic obstacles to failed reduction may be identified. Technical and interpretative challenges of spica MRI are discussed. (orig.)

Multi-modal image registration: matching MRI with histology

Science.gov (United States)

Alic, Lejla; Haeck, Joost C.; Klein, Stefan; Bol, Karin; van Tiel, Sandra T.; Wielopolski, Piotr A.; Bijster, Magda; Niessen, Wiro J.; Bernsen, Monique; Veenland, Jifke F.; de Jong, Marion

2010-03-01

Spatial correspondence between histology and multi sequence MRI can provide information about the capabilities of non-invasive imaging to characterize cancerous tissue. However, shrinkage and deformation occurring during the excision of the tumor and the histological processing complicate the co registration of MR images with histological sections. This work proposes a methodology to establish a detailed 3D relation between histology sections and in vivo MRI tumor data. The key features of the methodology are a very dense histological sampling (up to 100 histology slices per tumor), mutual information based non-rigid B-spline registration, the utilization of the whole 3D data sets, and the exploitation of an intermediate ex vivo MRI. In this proof of concept paper, the methodology was applied to one tumor. We found that, after registration, the visual alignment of tumor borders and internal structures was fairly accurate. Utilizing the intermediate ex vivo MRI, it was possible to account for changes caused by the excision of the tumor: we observed a tumor expansion of 20%. Also the effects of fixation, dehydration and histological sectioning could be determined: 26% shrinkage of the tumor was found. The annotation of viable tissue, performed in histology and transformed to the in vivo MRI, matched clearly with high intensity regions in MRI. With this methodology, histological annotation can be directly related to the corresponding in vivo MRI. This is a vital step for the evaluation of the feasibility of multi-spectral MRI to depict histological groundtruth.

Non-parametric Bayesian graph models reveal community structure in resting state fMRI

DEFF Research Database (Denmark)

Andersen, Kasper Winther; Madsen, Kristoffer H.; Siebner, Hartwig Roman

2014-01-01

Modeling of resting state functional magnetic resonance imaging (rs-fMRI) data using network models is of increasing interest. It is often desirable to group nodes into clusters to interpret the communication patterns between nodes. In this study we consider three different nonparametric Bayesian...... models for node clustering in complex networks. In particular, we test their ability to predict unseen data and their ability to reproduce clustering across datasets. The three generative models considered are the Infinite Relational Model (IRM), Bayesian Community Detection (BCD), and the Infinite...... between clusters. BCD restricts the between-cluster link probabilities to be strictly lower than within-cluster link probabilities to conform to the community structure typically seen in social networks. IDM only models a single between-cluster link probability, which can be interpreted as a background...

Normal pancreatic exocrine function does not exclude MRI/MRCP chronic pancreatitis findings.

Science.gov (United States)

Alkaade, Samer; Cem Balci, Numan; Momtahen, Amir Javad; Burton, Frank

2008-09-01

Abnormal pancreatic function tests have been reported to precede the imaging findings of chronic pancreatitis. Magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP) is increasingly accepted as the primary imaging modality for the detection of structural changes of early mild chronic pancreatitis. The aim of this study was to evaluate MRI/MRCP findings in patients with symptoms consistent with chronic pancreatitis who have normal Secretin Endoscopic Pancreatic Function test. A retrospective study of 32 patients referred for evaluation of chronic abdominal pain consistent with chronic pancreatitis and reported normal standard abdominal imaging (ultrasound, computed tomography, or MRI). All patients underwent Secretin Endoscopic Pancreatic Function testing and pancreatic MRI/MRCP at our institution. We reviewed the MRI/MRCP images in patients who had normal Secretin Endoscopic Pancreatic Function testing. MRI/MRCP images were assessed for pancreatic duct morphology, gland size, parenchymal signal and morphology, and arterial contrast enhancement. Of the 32 patients, 23 had normal Secretin Endoscopic Pancreatic Function testing, and 8 of them had mild to marked spectrum of abnormal MRI/MRCP findings that were predominantly focal. Frequencies of the findings were as follows: pancreatic duct stricture (n=3), pancreatic duct dilatation (n=3), side branch ectasia (n=4), atrophy (n=5), decreased arterial enhancement (n=5), decreased parenchymal signal (n=1), and cavity formation (n=1). The remaining15 patients had normal pancreatic structure on MRI/MRCP. Normal pancreatic function testing cannot exclude abnormal MRI/MRCP especially focal findings of chronic pancreatitis. Further studies needed to verify significance of these findings and establish MRI/MRCP imaging criteria for the diagnosis of chronic pancreatitis.

Clinical usefulness of MRI and MRA in children with partial epilepsy

International Nuclear Information System (INIS)

Zajac, A.; Kacinski, M.; Kubik, A.; Kroczka, S.

2006-01-01

Partial epilepsy is a very important problem of epileptology in childhood including clinical and therapeutic aspect especially surgery treatment. The aim of this study is to assess clinical value of neuroimagine techniques (structural MRI, MRI angiography) in partial epilepsy diagnostics in children. The relation between results of examinations with these methods and congenital and acquired risk factors related to partial epilepsy, age of its onset and clinical assessment of patients was analyzed. The study group consisted of 140 children with partial epilepsy hospitalized between 1998 and 2004 in Department of Pediatric Neurology, Collegium Medicum Jagiellonian University, Krakow. The group included 70 girls and 70 boys, the age ranged from 2 months to 17 years. In study group statistical analysis included different factors as which can be related with results of neuroimaging as age, load of pregnancy and birth period, familiar epilepsy, patient's risk factors for appearance of epilepsy, acquired risk factors of epilepsy, results of neurological examination, type of epilepsy, status epilepticus, and signs according epileptic attacks which can be related with neuroimaging results. The primary method of neuroimagine in all patients was structural MRI, in 16 cases Magnetic Resonance Angiography (MRA). The parametric tests (t-student), nonparametric Mann-Whitney's test were used in statistical analysis. The bilateral Fisher test was used to check rate in groups. There was assessed sensitivity, specificity, positive predictive value, negative predictive value; the 95% confidence interval was calculated for these parameters. Abnormalities in neurological examination in children with partial epilepsy were strongly correlated with MRI findings. The structural changes in MRI were found in younger children, whose course of epilepsy was longer than children without MRI changes. Changes in hippocampus ere the most common in children with partial epilepsy with abnormalities in

MR-Imaging of teeth and periodontal apparatus: an experimental study comparing high-resolution MRI with MDCT and CBCT

International Nuclear Information System (INIS)

Gaudino, Chiara; Csernus, Reka; Pham, Mirko; Bendszus, Martin; Rohde, Stefan; Cosgarea, Raluca; Kim, Ti-Sun; Heiland, Sabine; Beomonte Zobel, Bruno

2011-01-01

The aim of this study was (1) to assess the ability of magnetic resonance imaging (MRI) to visualize dental and periodontal structures and (2) to compare findings with multidetector computed tomography (MDCT) and cone beam CT (CBCT). Four porcine mandibles were examined with (1) 3T-MRI, (2) MDCT and (3) CBCT. Two observers independently reviewed MR, MDCT and CBCT images and assessed image quality of different dental and periodontal structures. To assess quantitatively the accuracy of the different imaging technique, both observers measured burr holes, previously drilled in the mandibles. Dental structures, e.g. teeth roots, pulpa chamber and dentin, were imaged accurately with all imaging sources. Periodontal space and cortical/trabecular bone were better visualized by MRI (p < 0.001). MRI could excellently display the lamina dura, not detectable with MDCT and only inconstant visible with CBCT (p < 0.001). Burr hole measurements were highly precise with all imaging techniques. This experimental study shows the diagnostic feasibility of MRI in visualization of teeth and periodontal anatomy. Detection of periodontal structures was significantly better with MRI than with MDCT or CBCT. Prospective trials have to evaluate further the potential benefit of MRI in a clinical setting. (orig.)

MR-Imaging of teeth and periodontal apparatus: an experimental study comparing high-resolution MRI with MDCT and CBCT

Energy Technology Data Exchange (ETDEWEB)

Gaudino, Chiara; Csernus, Reka; Pham, Mirko; Bendszus, Martin; Rohde, Stefan [University Hospital Heidelberg, Department of Neuroradiology, Heidelberg (Germany); Cosgarea, Raluca; Kim, Ti-Sun [University Hospital Heidelberg, Department of Periodontology, Heidelberg (Germany); Heiland, Sabine [University Hospital Heidelberg, Section of Experimental Radiology, Heidelberg (Germany); Beomonte Zobel, Bruno [University Campus Bio-Medico of Rome, Department of Radiology, Interdisciplinary Center for Biomedical Research, Rome (Italy)

2011-12-15

The aim of this study was (1) to assess the ability of magnetic resonance imaging (MRI) to visualize dental and periodontal structures and (2) to compare findings with multidetector computed tomography (MDCT) and cone beam CT (CBCT). Four porcine mandibles were examined with (1) 3T-MRI, (2) MDCT and (3) CBCT. Two observers independently reviewed MR, MDCT and CBCT images and assessed image quality of different dental and periodontal structures. To assess quantitatively the accuracy of the different imaging technique, both observers measured burr holes, previously drilled in the mandibles. Dental structures, e.g. teeth roots, pulpa chamber and dentin, were imaged accurately with all imaging sources. Periodontal space and cortical/trabecular bone were better visualized by MRI (p < 0.001). MRI could excellently display the lamina dura, not detectable with MDCT and only inconstant visible with CBCT (p < 0.001). Burr hole measurements were highly precise with all imaging techniques. This experimental study shows the diagnostic feasibility of MRI in visualization of teeth and periodontal anatomy. Detection of periodontal structures was significantly better with MRI than with MDCT or CBCT. Prospective trials have to evaluate further the potential benefit of MRI in a clinical setting. (orig.)

Gliomatosis cerebri: The diagnostic potential of MRI

International Nuclear Information System (INIS)

Rodiek, S.O.; Hufnagl, J.M.; Staedtisches Krankenhaus Muenchen-Bogenhausen

1991-01-01

Gliomatosis cerebri is a rare tumor of neuroepithelial origin in middle aged persons. MRI predominantly shows a bilateral and diffuse infiltration of midline adjacent brain structures including medulla. Areas with focal anaplasia occasionally reveal an accumulation of contrast media. The diffuse tumor manifestation requires a differentiation from encephalitis and demyelinating diseases with a similar distribution pattern of lesions. Three cases have been examined. In conclusion the performance of MRI including control and brain biopsy are indicated to establish an in vivo diagnosis. (orig./GDG) [de

Fusion of PET and MRI for Hybrid Imaging

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Cho, Zang-Hee; Son, Young-Don; Kim, Young-Bo; Yoo, Seung-Schik

Recently, the development of the fusion PET-MRI system has been actively studied to meet the increasing demand for integrated molecular and anatomical imaging. MRI can provide detailed anatomical information on the brain, such as the locations of gray and white matter, blood vessels, axonal tracts with high resolution, while PET can measure molecular and genetic information, such as glucose metabolism, neurotransmitter-neuroreceptor binding and affinity, protein-protein interactions, and gene trafficking among biological tissues. State-of-the-art MRI systems, such as the 7.0 T whole-body MRI, now can visualize super-fine structures including neuronal bundles in the pons, fine blood vessels (such as lenticulostriate arteries) without invasive contrast agents, in vivo hippocampal substructures, and substantia nigra with excellent image contrast. High-resolution PET, known as High-Resolution Research Tomograph (HRRT), is a brain-dedicated system capable of imaging minute changes of chemicals, such as neurotransmitters and -receptors, with high spatial resolution and sensitivity. The synergistic power of the two, i.e., ultra high-resolution anatomical information offered by a 7.0 T MRI system combined with the high-sensitivity molecular information offered by HRRT-PET, will significantly elevate the level of our current understanding of the human brain, one of the most delicate, complex, and mysterious biological organs. This chapter introduces MRI, PET, and PET-MRI fusion system, and its algorithms are discussed in detail.

Fetal MRI: An approach to practice: A review

Directory of Open Access Journals (Sweden)

Sahar N. Saleem

2014-09-01

Full Text Available MRI has been increasingly used for detailed visualization of the fetus in utero as well as pregnancy structures. Yet, the familiarity of radiologists and clinicians with fetal MRI is still limited. This article provides a practical approach to fetal MR imaging. Fetal MRI is an interactive scanning of the moving fetus owed to the use of fast sequences. Single-shot fast spin-echo (SSFSE T2-weighted imaging is a standard sequence. T1-weighted sequences are primarily used to demonstrate fat, calcification and hemorrhage. Balanced steady-state free-precession (SSFP, are beneficial in demonstrating fetal structures as the heart and vessels. Diffusion weighted imaging (DWI, MR spectroscopy (MRS, and diffusion tensor imaging (DTI have potential applications in fetal imaging. Knowing the developing fetal MR anatomy is essential to detect abnormalities. MR evaluation of the developing fetal brain should include recognition of the multilayered-appearance of the cerebral parenchyma, knowledge of the timing of sulci appearance, myelination and changes in ventricular size. With advanced gestation, fetal organs as lungs and kidneys show significant changes in volume and T2-signal. Through a systematic approach, the normal anatomy of the developing fetus is shown to contrast with a wide spectrum of fetal disorders. The abnormalities displayed are graded in severity from simple common lesions to more complex rare cases. Complete fetal MRI is fulfilled by careful evaluation of the placenta, umbilical cord and amniotic cavity. Accurate interpretation of fetal MRI can provide valuable information that helps prenatal counseling, facilitate management decisions, guide therapy, and support research studies.

Using multivariate machine learning methods and structural MRI to classify childhood onset schizophrenia and healthy controls

Directory of Open Access Journals (Sweden)

Deanna eGreenstein

2012-06-01

Full Text Available Introduction: Multivariate machine learning methods can be used to classify groups of schizophrenia patients and controls using structural magnetic resonance imaging (MRI. However, machine learning methods to date have not been extended beyond classification and contemporaneously applied in a meaningful way to clinical measures. We hypothesized that brain measures would classify groups, and that increased likelihood of being classified as a patient using regional brain measures would be positively related to illness severity, developmental delays and genetic risk. Methods: Using 74 anatomic brain MRI sub regions and Random Forest, we classified 98 COS patients and 99 age, sex, and ethnicity-matched healthy controls. We also used Random Forest to determine the likelihood of being classified as a schizophrenia patient based on MRI measures. We then explored relationships between brain-based probability of illness and symptoms, premorbid development, and presence of copy number variation associated with schizophrenia. Results: Brain regions jointly classified COS and control groups with 73.7% accuracy. Greater brain-based probability of illness was associated with worse functioning (p= 0.0004 and fewer developmental delays (p=0.02. Presence of copy number variation (CNV was associated with lower probability of being classified as schizophrenia (p=0.001. The regions that were most important in classifying groups included left temporal lobes, bilateral dorsolateral prefrontal regions, and left medial parietal lobes. Conclusions: Schizophrenia and control groups can be well classified using Random Forest and anatomic brain measures, and brain-based probability of illness has a positive relationship with illness severity and a negative relationship with developmental delays/problems and CNV-based risk.

A brain MRI atlas of the common squirrel monkey, Saimiri sciureus

Science.gov (United States)

Gao, Yurui; Schilling, Kurt G.; Khare, Shweta P.; Panda, Swetasudha; Choe, Ann S.; Stepniewska, Iwona; Li, Xia; Ding, Zhoahua; Anderson, Adam; Landman, Bennett A.

2014-03-01

The common squirrel monkey, Saimiri sciureus, is a New World monkey with functional and microstructural organization of central nervous system similar to that of humans. It is one of the most commonly used South American primates in biomedical research. Unlike its Old World macaque cousins, no digital atlases have described the organization of the squirrel monkey brain. Here, we present a multi-modal magnetic resonance imaging (MRI) atlas constructed from the brain of an adult female squirrel monkey. In vivo MRI acquisitions include high resolution T2 structural imaging and low resolution diffusion tensor imaging. Ex vivo MRI acquisitions include high resolution T2 structural imaging and high resolution diffusion tensor imaging. Cortical regions were manually annotated on the co-registered volumes based on published histological sections.

MRI assessment program. Consensus statement on clinical efficacy of MRI

International Nuclear Information System (INIS)

1998-05-01

This consensus statement is largely based on the experience gained at the MRI units at the four hospitals which have operated scanners in the MRI program. It reflects the considered opinion of the radiologists responsible for the MRI services at those hospitals. Account has also been taken of relevant overseas data. This collection of opinion relates particularly to comparison with other imaging modalities. The specific comments will require further consideration as technical developments with MRI become available, additional experience is gained with gadolinium contrast material and additional data are obtained on the influence of MRI on patient management. MRI, at present, is used either to improve diagnostic accuracy when other tests are negative or equivocal, when there is strong clinical suspicion of disease, or to improve surgical or other management planning when the diagnosis known. In some situations (eg syringomyelia, congenital spinal disease, posterior fossa/cerebello-pontine angle tumours) it may entirely replace other tests (eg myelography, air contrast, CT) which are substantially less accurate and/or more invasive. In other situations (eg hemispheric brain tumours, lumbar disc protrusions) when other tests, such as CT, can be as accurate, MRI is not usually or initially indicated because it is currently more expensive and of limited availability. However, balanced against this is the fact that it does not expose the patient to potentially harmful ionising radiation. It is also stressed that MRI images depend on complex, widely variable and, as yet, incompletely understood parameters. There is concern that this may result in false positive diagnoses, especially where MRI is used alone as a screening test, or used as the initial test. For several reasons (availability, cost, medical and diagnostic efficacy), the specific comments on indications for MRI presented are based upon the assumption that MRI is a tertiary and complementary imaging examination

MRI

DEFF Research Database (Denmark)

Schroeter, Aileen; Rudin, Markus; Gianolio, Eliana

2017-01-01

This chapter discusses principles of nuclear magnetic resonance (NMR) and MRI followed by a survey on the major classes of MRI contrast agents (CA), their modes of action, and some of the most significative applications. The two more established classes of MRI-CA are represented by paramagnetic...... been attained that markedly increase the number and typology of systems with CEST properties. Currently much attention is also devoted to hyperpolarized molecules that display a sensitivity enhancement sufficient for their direct exploitation for the formation of the MR image. A real breakthrough...

Quantitative structure-property relationship (correlation analysis) of phosphonic acid-based chelates in design of MRI contrast agent.

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Tiwari, Anjani K; Ojha, Himanshu; Kaul, Ankur; Dutta, Anupama; Srivastava, Pooja; Shukla, Gauri; Srivastava, Rakesh; Mishra, Anil K

2009-07-01

Nuclear magnetic resonance imaging is a very useful tool in modern medical diagnostics, especially when gadolinium (III)-based contrast agents are administered to the patient with the aim of increasing the image contrast between normal and diseased tissues. With the use of soft modelling techniques such as quantitative structure-activity relationship/quantitative structure-property relationship after a suitable description of their molecular structure, we have studied a series of phosphonic acid for designing new MRI contrast agent. Quantitative structure-property relationship studies with multiple linear regression analysis were applied to find correlation between different calculated molecular descriptors of the phosphonic acid-based chelating agent and their stability constants. The final quantitative structure-property relationship mathematical models were found as--quantitative structure-property relationship Model for phosphonic acid series (Model 1)--log K(ML) = {5.00243(+/-0.7102)}- MR {0.0263(+/-0.540)}n = 12 l r l = 0.942 s = 0.183 F = 99.165 quantitative structure-property relationship Model for phosphonic acid series (Model 2)--log K(ML) = {5.06280(+/-0.3418)}- MR {0.0252(+/- .198)}n = 12 l r l = 0.956 s = 0.186 F = 99.256.

The role of MRI in suspected inner ear malformations

International Nuclear Information System (INIS)

Koesling, S.; Juettemann, S.; Amaya, B.; Rasinski, C.; Bloching, M.; Koenig, E.

2003-01-01

Purpose: This is a prospective analysis of the value of MRI in suspected inner ear malformations. Materials and Methods: In 50 patients (43 children and young adults, 7 adults) with suspected inner ear malformation MRI (1.5 T) was performed. In addition, 42 of these patients underwent CT. For the analysis of the inner ear structures, the constructive interference in steady state (CISS) sequence with 0.7 mm slice thickness was used. Functional tests revealed a sensorineural hearing loss or deafness in 82 temporal bones (TB) and a combined hearing loss in 4 TB. The hearing loss was unilateral in 14 patients. MRI and CT findings were compared. Results: Imaging findings were normal in 58 TB. The pathological findings included inner ear malformations (35 TB), inflammatory changes (4 TB), partial obliteration of labyrinth (2 TB) and congenital aural atresia (1 TB). An isolated absence of the cochlear nerve (1 TB) could only be found by MRI. In the remaining cases, an inner ear malformation was diagnosed by MRI and CT with the same confidence but MRI was superior in displaying the fine details. Conclusions: MRI will become the method of choice in the diagnosis of inner ear malformations. (orig.) [de

Advanced MRI techniques of the fetal brain

International Nuclear Information System (INIS)

Schoepf, V.; Dittrich, E.; Berger-Kulemann, V.; Kasprian, G.; Kollndorfer, K.; Prayer, D.

2013-01-01

Evaluation of the normal and pathological fetal brain. Magnetic resonance imaging (MRI). Advanced MRI of the fetal brain. Diffusion tensor imaging (DTI) is used in clinical practice, all other methods are used at a research level. Serving as standard methods in the future. Combined structural and functional data for all gestational ages will allow more specific insight into the developmental processes of the fetal brain. This gain of information will help provide a common understanding of complex spatial and temporal procedures of early morphological features and their impact on cognitive and sensory abilities. (orig.) [de

MRI characteristics of midbrain tumours

International Nuclear Information System (INIS)

Sun, B.; Wang, C.C.; Wang, J.

1999-01-01

We diagnosed 60 cases of midbrain tumours by MRI between 1993 to 1997. There were 39 males and 21 females, aged 2-64 years, mean 25.6 years. We found 38 patients with true intramedullary midbrain tumours, 11 predominantly in the tectum, 20 in the tegmentum and 7 with a downward extension to the pons; there were 7 within the cerebral aqueduct. There were 22 patients with infiltrating midbrain tumours extending from adjacent structures, 11 cases each from the thalamus and pineal region. All patients received surgical treatment. Gross total resection was achieved in 42 cases, subtotal (> 75 %) resection in 18. Pathological diagnoses included 16 low-grade and 15 high-grade astrocytomas; 5 oligodendroastrocytomas; 2 ependymomas; 11 glioblastomas; and 11 pineal parenchymal or germ-cell tumours. Midbrain tumours are a heterogeneous group of neoplasms, with wide variation in clinical and MRI features, related to the site and type of tumour. MRI not only allows precise analysis of their growth pattern, but also can lead to a correct preoperative diagnosis in the majority of cases. (orig.) (orig.)

An MRI-Conditional External Cardiac Defibrillator for Resuscitation Within the MRI Scanner Bore

Science.gov (United States)

Schmidt, Ehud J.; Watkins, Ronald D.; Zviman, Menekhem M.; Guttman, Michael A.; Wang, Wei; Halperin, Henry A.

2016-01-01

Background Subjects undergoing cardiac arrest within an MRI scanner are currently removed from the bore and then from the MRI suite, prior to delivery of CPR and defibrillation, potentially increasing risk of mortality. This precludes many higher-risk (acute-ischemic, acute-stroke) patients from undergoing MRI imaging and MRI-guided intervention. An MRI-conditional cardiac defibrillator should enable scanning with defibrillation pads attached and the generator ON, enabling application of defibrillation within the MRI seconds after a cardiac event. An MRI-conditional external defibrillator may improve patient acceptance for MRI procedures. Methods and Results A commercial external defibrillator was rendered 1.5 Tesla MRI-conditional by addition of novel Radio-Frequency (RF) filters between the generator and commercial disposable surface-pads. The RF filters reduced emission into the MRI scanner, and prevented cable/surface-pad heating during imaging, while preserving all the defibrillator’s monitoring and delivery functions. Human volunteers were imaged using high Specific-Absorption-Rate sequences to validate MRI image quality (IQ) and lack of heating. Swine were electrically fibrillated (N=4) and thereafter defibrillated both outside and inside the MRI bore. MRI IQ was reduced by 0.8 or 1.6 dB, with the generator in monitoring mode and operating on battery or AC power, respectively. Commercial surface-pads did not create artifacts deeper than 6mm below the skin surface. RF heating was within FDA guidelines. Defibrillation was completely successful inside and outside the MRI bore. Conclusions A prototype MRI-conditional defibrillation system successfully defibrillated in the MRI without degrading image quality, or increasing the time needed for defibrillation. It can increase patient acceptance for MRI procedures. PMID:27729363

MRI reporting by radiographers: The construction of an objective structured examination

International Nuclear Information System (INIS)

Piper, K.J.; Buscall, K.L.

2008-01-01

Purpose: The aim was to construct a bank of general magnetic resonance imaging (MRI) investigations where good agreement was demonstrated between three independent radiological reports. The bank was subsequently to be used to assess radiographers' ability to accurately report at the end of an accredited programme; Postgraduate Certificate (PgC) Clinical Reporting (MRI-General Investigations). Method: Eighty-seven examinations (33 knee, 36 lumbar spine and 18 internal auditory meatus-IAM) were initially reported by two radiologists. Seventy-two of these examinations (25 knee, 29 lumbar spine and 18 IAM) were subsequently reported by a third radiologist. Interobserver agreement was assessed by estimating the total, positive and negative % agreement rates; and by use of the weighted or unweighted kappa values. Knee reports were analysed for meniscal tears, and degenerative meniscus (264 meniscal sites); ligament injury (ACL; PCL; MCI; and LCL; 132 ligament sites); bone bruise; effusion; fracture and/or osteochondral defect. Lumbar spine reports were analysed for disc morphology (bulge, protrusion, extrusion and/or annular tear-180 intervertebral disc levels); degenerative disc disease; Modic endplate changes; cord compression; spinal stenosis; nerve root involvement; vertebral collapse, primary tumour or metastases; and other incidental findings. IAM reports were analysed for acoustic neuroma and vascular loop. Results: Agreement in the knee reports varied mainly between moderate (κ = 0.46) for ligament injury to very good [almost perfect] (κ = 0.86) for meniscal tears, although agreement for degenerative meniscus was only fair (κ = 0.3). Variation in the lumbar spine reports ranged predominantly between moderate (κ = 0.54) for disc bulge/protrusion to fair (κ = 0.32) for Modic endplate changes to good [substantial] (κ = 0.79) for tumour/metastases. Agreement for the presence of acoustic neuroma was very good [almost perfect] (κ = 1.0). Forty cases

MRI-based multiscale models for the hemodynamic and structural evaluation of surgically reconstructed aortic arches

DEFF Research Database (Denmark)

Pittaccio, S; Migliavacca, F; Balossino, R

2007-01-01

) geometries of a porcine aortic arch were derived from magnetic resonance imaging (MRI) images. Inlet conditions were derived from MRI velocimetry. A multiscale approach was used for the imposition of outlet conditions, wherein a lumped parameter net provided an active afterload. Evidence was found that ring...

Biopsy guided by real-time sonography fused with MRI: a phantom study

DEFF Research Database (Denmark)

Ewertsen, C.; Grossjohann, Hanne Sønder; Nielsen, Kristina Rue

2008-01-01

OBJECTIVE: The purpose of our study was to test the accuracy of sonographically guided biopsies in a phantom of structures not visible on sonography but shown on MRI by using commercially available sonography systems with image fusion software. MATERIALS AND METHODS: A previously recorded MRI...

MRI of head trauma. Serial changes and comparison with CT

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Fukuda, Osamu; Sato, Shuji; Suzuki, Takashi; Endo, Shunro; Takaku, Akira.

1988-08-01

Sequential changes in magnetic resonance imaging (MRI) were investigated in comparison with computed tomography (CT) in 31 cases of head trauma. Twenty-one of them were of acute head trauma; the first MRI study was performed within 48 hours after the accident. Forty-two intracranial lesions were observed in these cases on MRI. The other 10 cases were of chronic subdural hematoma, two cases of which had bilateral lesions. Fourteen lesions of acute head trauma and two lesions of chronic subdural hematoma were detected only by MRI. MRI was superior to CT for the detection of small contusions and thin extra-axial collections, especially those which were located near the bony structures. The abnormal lesions were visualized in MRI during a longer period than in CT. Because the signal intensity of a hematoma changed sequentially, the detection of brain edema was easier than that of a subarachnoid and parenchimal hemorrhage. Judging from this experience, it seems that careful attention should be taken in the diagnosis of hemorrhagic lesions. However, MRI was poor in tissue characterization because of the too-high tissue sensitivity. T/sub 2/-weight SE imaging was essentially sensitive and useful in the early stage.

Thalamotemporal impairment in temporal lobe epilepsy: a combined MRI analysis of structure, integrity, and connectivity.

Science.gov (United States)

Keller, Simon S; O'Muircheartaigh, Jonathan; Traynor, Catherine; Towgood, Karren; Barker, Gareth J; Richardson, Mark P

2014-02-01

Thalamic abnormality in temporal lobe epilepsy (TLE) is well known from imaging studies, but evidence is lacking regarding connectivity profiles of the thalamus and their involvement in the disease process. We used a novel multisequence magnetic resonance imaging (MRI) protocol to elucidate the relationship between mesial temporal and thalamic pathology in TLE. For 23 patients with TLE and 23 healthy controls, we performed T1 -weighted (for analysis of tissue structure), diffusion tensor imaging (tissue connectivity), and T1 and T2 relaxation (tissue integrity) MRI across the whole brain. We used connectivity-based segmentation to determine connectivity patterns of thalamus to ipsilateral cortical regions (occipital, parietal, prefrontal, postcentral, precentral, and temporal). We subsequently determined volumes, mean tractography streamlines, and mean T1 and T2 relaxometry values for each thalamic segment preferentially connecting to a given cortical region, and of the hippocampus and entorhinal cortex. As expected, patients had significant volume reduction and increased T2 relaxation time in ipsilateral hippocampus and entorhinal cortex. There was bilateral volume loss, mean streamline reduction, and T2 increase of the thalamic segment preferentially connected to temporal lobe, corresponding to anterior, dorsomedial, and pulvinar thalamic regions, with no evidence of significant change in any other thalamic segments. Left and right thalamotemporal segment volume and T2 were significantly correlated with volume and T2 of ipsilateral (epileptogenic), but not contralateral (nonepileptogenic), mesial temporal structures. These convergent and robust data indicate that thalamic abnormality in TLE is restricted to the area of the thalamus that is preferentially connected to the epileptogenic temporal lobe. The degree of thalamic pathology is related to the extent of mesial temporal lobe damage in TLE. © 2014 The Authors. Epilepsia published by Wiley Periodicals, Inc

Wilson's disease: cranial MRI observations and clinical correlation

International Nuclear Information System (INIS)

Sinha, S.; Taly, A.B.; Prashanth, L.K.; Venugopal, K.S.; Arunodaya, G.R.; Swamy, H.S.; Ravishankar, S.; Vasudev, M.K.

2006-01-01

Study of MRI changes may be useful in diagnosis, prognosis and better understanding of the pathophysiology of Wilson's disease (WD). We aimed to describe and correlate the MRI abnormalities of the brain with clinical features in WD. MRI evaluation was carried out in 100 patients (57 males, 43 females; mean age 19.3±8.9 years) using standard protocols. All but 18 patients were on de-coppering agents. Their history, clinical manifestations and scores for severity of disease were noted. The mean duration of illness and treatment were 8.3±10.8 years and 7.5±7.1 years respectively. MRI of the brain was abnormal in all the 93 symptomatic patients. The most conspicuous observations were atrophy of the cerebrum (70%), brainstem (66%) and cerebellum (52%). Signal abnormalities were also noted: putamen (72%), caudate (61%), thalami (58%), midbrain (49%), pons (20%), cerebral white matter (25%), cortex (9%), medulla (12%) and cerebellum (10%). The characteristic T2-W globus pallidal hypointensity (34%), ''Face of giant panda'' sign (12%), T1-W striatal hyperintensity (6%), central pontine myelinosis (7%), and bright claustral sign (4%) were also detected. MRI changes correlated with disease severity scores (P<0.001) but did not correlate with the duration of illness. MRI changes were universal but diverse and involved almost all the structures of the brain in symptomatic patients. A fair correlation between MRI observations and various clinical features provides an explanation for the protean manifestations of the disease. (orig.)

APPLICATION OF MRI IN THE DIAGNOSTICS OF M. MASSETER

Directory of Open Access Journals (Sweden)

Mariana Dimova-Gabrovska

2017-06-01

Full Text Available Magnetic resonance imaging (MRI is a non-invasive diagnostic method which can provide detailed images of organs and structures of the human body. The purpose of this review is to explore and introduce the diagnostic capabilities of MRI in imaging m. masseter in conditions of norm and pathology. The material of the review is information of 20 literary sources selected from 530, found by keywordsfromJanuary to April 2017. The information about MRI imaging of the normal anatomy of m. masseter and the most common findings in muscle - muscle hypertrophy, inflammatory changes, vascular malformations, intramuscular hemangioma, cysticercosis and changes after radiotherapy was analyzed. In conclusion, the diagnostic capabilities of MRI of masseter muscle – both in the conditions of norm and pathology were confirmed. The method is considered to be reliable, objective, non-invasive and accurate.

Inter-subject phase synchronization for exploratory analysis of task-fMRI.

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Bolt, Taylor; Nomi, Jason S; Vij, Shruti G; Chang, Catie; Uddin, Lucina Q

2018-08-01

Analysis of task-based fMRI data is conventionally carried out using a hypothesis-driven approach, where blood-oxygen-level dependent (BOLD) time courses are correlated with a hypothesized temporal structure. In some experimental designs, this temporal structure can be difficult to define. In other cases, experimenters may wish to take a more exploratory, data-driven approach to detecting task-driven BOLD activity. In this study, we demonstrate the efficiency and power of an inter-subject synchronization approach for exploratory analysis of task-based fMRI data. Combining the tools of instantaneous phase synchronization and independent component analysis, we characterize whole-brain task-driven responses in terms of group-wise similarity in temporal signal dynamics of brain networks. We applied this framework to fMRI data collected during performance of a simple motor task and a social cognitive task. Analyses using an inter-subject phase synchronization approach revealed a large number of brain networks that dynamically synchronized to various features of the task, often not predicted by the hypothesized temporal structure of the task. We suggest that this methodological framework, along with readily available tools in the fMRI community, provides a powerful exploratory, data-driven approach for analysis of task-driven BOLD activity. Copyright © 2018 Elsevier Inc. All rights reserved.

Phosphorus-31 MRI of bones using quadratic echo line-narrowing

Science.gov (United States)

Frey, Merideth; Barrett, Sean; Insogna, Karl; Vanhouten, Joshua

2012-02-01

There is a great need to probe the internal composition of bone on the sub-0.1 mm length scale, both to study normal features and to look for signs of disease. Despite the obvious importance of the mineral fraction to the biomechanical properties of skeletal tissue, few non-destructive techniques are available to evaluate changes in its chemical structure and functional microarchitecture on the interior of bones. MRI would be an excellent candidate, but bone is a particularly challenging tissue to study given the relatively low water density and wider linewidths of its solid components. Recent fundamental research in quantum computing gave rise to a new NMR pulse sequence - the quadratic echo - that can be used to narrow the broad NMR spectrum of solids. This offers a new route to do high spatial resolution, 3D ^31P MRI of bone that complements conventional MRI and x-ray based techniques to study bone physiology and structure. We have used our pulse sequence to do 3D ^31P MRI of ex vivo bones with a spatial resolution of (sub-450 μm)^3, limited only by the specifications of a conventional 4 Tesla liquid-state MRI system. We will describe our plans to push this technique towards the factor of 1000 increase in spatial resolution imposed by fundamental limits.

Arrhythmogenic right ventricular dysplasia: MRI findings

International Nuclear Information System (INIS)

Wall, E.E. van der; Bootsma, M.M.; Schalij, M.J.; Kayser, H.W.M.; Roos, A. de

2000-01-01

Arrhythmogenic right ventricular dysplasia (ARVD) is a heart muscle disorder of unknown cause that is characterized pathologically by fibrofatty replacement of the right ventricular myocardium. Clinical manifestations include structural and functional malformations of the right ventricle, electrocardiographic abnormalities, and presentation with ventricular tachycardias with left bundle branch pattern or sudden death. The disease is often familial with an autosomal inheritance. In addition to right ventricular dilatation, right ventricular aneurysms are typical deformities of ARVD and they are distributed in the so-called ''triangle of dysplasia'', i. e., right ventricular outflow tract, apex, and infundibulum. Ventricular aneurysms at these sites can be considered pathognomonic of ARVD. Another typical hallmark of ARVD is fibrofatty infiltration of the right ventricular free wall. These functional and morphologic characteristics are relevant to clinical imaging investigations such as contrast angiography, echocardiography, radionuclide angiography, ultrafast computed tomography, and magnetic resonance imaging (MRI). Among these techniques, MRI allows the clearest visualization of the heart, in particular because the right ventricle is involved, which is usually more difficult to explore with the other imaging modalities. Furthermore, MRI offers the specific advantage of visualizing adipose infiltration as a bright signal of the right ventricular myocardium. MRI provides the most important anatomic, functional, and morphologic criteria for diagnosis of ARVD within one single study. As a result, MRI appears to be the optimal imaging technique for detecting and following patients with clinical suspicion of ARVD. (orig.) [de

MRI characterization of structural mouse brain changes in response to chronic exposure to the glufosinate ammonium herbicide.

Science.gov (United States)

Meme, Sandra; Calas, André-Guilhem; Montécot, Céline; Richard, Oliver; Gautier, Hélène; Gefflaut, Thierry; Doan, Bich Thuy; Même, William; Pichon, Jacques; Beloeil, Jean-Claude

2009-10-01

Glufosinate ammonium (GLA) is the active component of herbicides widely used in agriculture, truck farming, or public domains. GLA acts by inhibiting the plant glutamine synthetase (GlnS). It also inhibits mammalian GlnS in vitro and ex vivo. In the central nervous system this enzyme is exclusively localized in glial cells. Whereas acute neurotoxic effects of GLA are well documented, long-term effects during chronic exposure at low doses remain largely undisclosed. In the present work, C57BL/6J mice were treated intraperitoneally with 2.5, 5, and 10 mg/kg of GLA three times a week during 10 weeks. Cerebral magnetic resonance imaging (MRI) experiments were performed at high field (9.4 T) and the images were analyzed with four texture analysis (TA) methods. TA highlighted structural changes in seven brain structures after chronic GLA treatments. Changes are dose dependent and can be seen at a dose as low as 2.5 mg/kg for two areas, namely hippocampus and somatosensorial cortex. Glial fibrillary acidic protein (GFAP) expression in the same seven brain structures and GlnS activity in the hippocampus and cortex areas were also studied. The number of GFAP-positive cells is modified in six out of the seven areas examined. GlnS activity was significantly increased in the hippocampus but not in the cortex. These results indicate some kind of suffering at the cerebral level after chronic GLA treatment. Changes in TA were compared with the modification of the number of GFAP-positive astrocytes in the studied brain areas after GLA treatment. We show that the noninvasive MRI-TA is a sensitive method and we suggest that it would be a very helpful tool that can efficiently contribute to the detection of cerebral alterations in vivo during chronic exposure to xenobiotics.

Development and assessment of a new 3D neuroanatomy teaching tool for MRI training.

Science.gov (United States)

Drapkin, Zachary A; Lindgren, Kristen A; Lopez, Michael J; Stabio, Maureen E

2015-01-01

A computerized three-dimensional (3D) neuroanatomy teaching tool was developed for training medical students to identify subcortical structures on a magnetic resonance imaging (MRI) series of the human brain. This program allows the user to transition rapidly between two-dimensional (2D) MRI slices, 3D object composites, and a combined model in which 3D objects are overlaid onto the 2D MRI slices, all while rotating the brain in any direction and advancing through coronal, sagittal, or axial planes. The efficacy of this tool was assessed by comparing scores from an MRI identification quiz and survey in two groups of first-year medical students. The first group was taught using this new 3D teaching tool, and the second group was taught the same content for the same amount of time but with traditional methods, including 2D images of brain MRI slices and 3D models from widely used textbooks and online sources. Students from the experimental group performed marginally better than the control group on overall test score (P = 0.07) and significantly better on test scores extracted from questions involving C-shaped internal brain structures (P teaching tool is an effective way to train medical students to read an MRI of the brain and is particularly effective for teaching C-shaped internal brain structures. © 2015 American Association of Anatomists.

MRI features of extraskeletal myxoid chondrosarcoma

Energy Technology Data Exchange (ETDEWEB)

Tateishi, Ukihide; Arai, Yasuaki [National Cancer Center Hospital, Division of Diagnostic Radiology, Tokyo (Japan); Hasegawa, Tadashi [Sapporo Medical University School of Medicine, Department of Clinical Pathology, Sapporo (Japan); Nojima, Takayuki [Kanazawa Medical University, Department of Pathology, Ishikawa (Japan); Takegami, Tsutomu [Kanazawa Medical University, Medical Research Institute, Ishikawa (Japan)

2006-01-01

To describe the MRI features of extraskeletal myxoid chondrosarcoma in comparison with clinicopathologic findings. The study comprised 12 male subjects and seven female subjects with a mean age of 53 years (range 16-76 years). MRI findings, evaluated by two radiologists with agreement by consensus, were compared for histopathologic features. The tumor size ranged from 2.0 cm to 20.0 cm (mean 8.9 cm). Fusion gene transcripts could be detected in 13 (68%) of the 19 cases: EWS-CHN in nine cases, TAF2N-CHN in three, and TFG-TCH in one. There were six fusion-negative cases. Signal characteristics on T1-weighted and T2-weighted MR images were non-specific with regard to each cytogenetic variant. Peripheral enhancement was seen more frequently in tumors with the EWS-CHN variant than in those with other cytogenetic variants. The characteristic pattern of enhancement corresponded to the presence of fibrous septa and peripheral areas of high cellularity within lobules, by correlation with pathologic findings. All cases with TAF2N-CHN or TFG-TCH variants showed invasion of extracompartmental structure, bone, or vessels. Extraskeletal myxoid chondrosarcoma is an uncommon soft-tissue malignancy that may be recognized by MRI features of multi-lobular soft-tissue mass often invading extracompartmental, bony, and vascular structures. (orig.)

Quantifying Pathology in Diffusion Weighted MRI

NARCIS (Netherlands)

Caan, M.W.A.

2010-01-01

In this thesis algorithms are proposed for quantification of pathology in Diffusion Weighted Magnetic Resonance Imaging (DW-MRI) data. Functional evidence for brain diseases can be explained by specific structural loss in the white matter of the brain. That is, certain biomarkers may exist where the

Comparison of static MRI and pseudo-dynamic MRI in temporomandibular joint disorder patients

International Nuclear Information System (INIS)

Lee, Jin Ho; Yun, Kyoung In; Park, In Woo; Choi, Hang Moon; Park, Moon Soo

2006-01-01

The purpose of this study was to elevate comparison of static MRI and pseudo-dynamic (cine) MRI in temporomandibular joint (TMJ) disorder patients. In this investigation, 33 patients with TMJ disorders were examined using both conventional static MRI and pseudo-dynamic MRI. Multiple spoiled gradient recalled acquisition in the steady state (SPGR) images were obtained when mouth opened and closed. Proton density weighted images were obtained at the closed and open mouth position in static MRI. Two oral and maxillofacial radiologists evaluated location of the articular disk, movement of condyle and bony change respectively and the posterior boundary of articular disk was obtained. No statistically significant difference was found in the observation of articular disk position, mandibular condylar movement and posterior boundary of articular disk using static MRI and pseudo-dynamic MRI (P>0.05). Statistically significant difference was noted in bony changes of condyle using static MRI and pseudo-dynamic MRI (P<0.05). This study showed that pseudo-dynamic MRI didn't make a difference in diagnosing internal derangement of TMJ in comparison with static MRI. But it was considered as an additional method to be supplemented in observing bony change

Comparison of static MRI and pseudo-dynamic MRI in temporomandibular joint disorder patients

Energy Technology Data Exchange (ETDEWEB)

Lee, Jin Ho; Yun, Kyoung In [Eulji Univ. School of Medicine, Seoul (Korea, Republic of); Park, In Woo; Choi, Hang Moon; Park, Moon Soo [Kangnung National Univ. College of Dentistry, Kangnung (Korea, Republic of)

2006-12-15

The purpose of this study was to elevate comparison of static MRI and pseudo-dynamic (cine) MRI in temporomandibular joint (TMJ) disorder patients. In this investigation, 33 patients with TMJ disorders were examined using both conventional static MRI and pseudo-dynamic MRI. Multiple spoiled gradient recalled acquisition in the steady state (SPGR) images were obtained when mouth opened and closed. Proton density weighted images were obtained at the closed and open mouth position in static MRI. Two oral and maxillofacial radiologists evaluated location of the articular disk, movement of condyle and bony change respectively and the posterior boundary of articular disk was obtained. No statistically significant difference was found in the observation of articular disk position, mandibular condylar movement and posterior boundary of articular disk using static MRI and pseudo-dynamic MRI (P>0.05). Statistically significant difference was noted in bony changes of condyle using static MRI and pseudo-dynamic MRI (P<0.05). This study showed that pseudo-dynamic MRI didn't make a difference in diagnosing internal derangement of TMJ in comparison with static MRI. But it was considered as an additional method to be supplemented in observing bony change.

Automatic Segmenting Structures in MRI's Based on Texture Analysis and Fuzzy Logic

Science.gov (United States)

Kaur, Mandeep; Rattan, Munish; Singh, Pushpinder

2017-12-01

The purpose of this paper is to present the variational method for geometric contours which helps the level set function remain close to the sign distance function, therefor it remove the need of expensive re-initialization procedure and thus, level set method is applied on magnetic resonance images (MRI) to track the irregularities in them as medical imaging plays a substantial part in the treatment, therapy and diagnosis of various organs, tumors and various abnormalities. It favors the patient with more speedy and decisive disease controlling with lesser side effects. The geometrical shape, the tumor's size and tissue's abnormal growth can be calculated by the segmentation of that particular image. It is still a great challenge for the researchers to tackle with an automatic segmentation in the medical imaging. Based on the texture analysis, different images are processed by optimization of level set segmentation. Traditionally, optimization was manual for every image where each parameter is selected one after another. By applying fuzzy logic, the segmentation of image is correlated based on texture features, to make it automatic and more effective. There is no initialization of parameters and it works like an intelligent system. It segments the different MRI images without tuning the level set parameters and give optimized results for all MRI's.

Neonatal Pulmonary MRI of Bronchopulmonary Dysplasia Predicts Short-term Clinical Outcomes.

Science.gov (United States)

Higano, Nara S; Spielberg, David R; Fleck, Robert J; Schapiro, Andrew H; Walkup, Laura L; Hahn, Andrew D; Tkach, Jean A; Kingma, Paul S; Merhar, Stephanie L; Fain, Sean B; Woods, Jason C

2018-05-23

Bronchopulmonary dysplasia (BPD) is a serious neonatal pulmonary condition associated with premature birth, but the underlying parenchymal disease and trajectory are poorly characterized. The current NICHD/NHLBI definition of BPD severity is based on degree of prematurity and extent of oxygen requirement. However, no clear link exists between initial diagnosis and clinical outcomes. We hypothesized that magnetic resonance imaging (MRI) of structural parenchymal abnormalities will correlate with NICHD-defined BPD disease severity and predict short-term respiratory outcomes. Forty-two neonates (20 severe BPD, 6 moderate, 7 mild, 9 non-BPD controls; 40±3 weeks post-menstrual age) underwent quiet-breathing structural pulmonary MRI (ultrashort echo-time and gradient echo) in a NICU-sited, neonatal-sized 1.5T scanner, without sedation or respiratory support unless already clinically prescribed. Disease severity was scored independently by two radiologists. Mean scores were compared to clinical severity and short-term respiratory outcomes. Outcomes were predicted using univariate and multivariable models including clinical data and scores. MRI scores significantly correlated with severities and predicted respiratory support at NICU discharge (P<0.0001). In multivariable models, MRI scores were by far the strongest predictor of respiratory support duration over clinical data, including birth weight and gestational age. Notably, NICHD severity level was not predictive of discharge support. Quiet-breathing neonatal pulmonary MRI can independently assess structural abnormalities of BPD, describe disease severity, and predict short-term outcomes more accurately than any individual standard clinical measure. Importantly, this non-ionizing technique can be implemented to phenotype disease and has potential to serially assess efficacy of individualized therapies.

Standardized evaluation of algorithms for computer-aided diagnosis of dementia based on structural MRI

DEFF Research Database (Denmark)

Bron, Esther E.; Smits, Marion; van der Flier, Wiesje M.

2015-01-01

algorithms based on a clinically representative multi-center data set. Using clinical practice as the starting point, the goal was to reproduce the clinical diagnosis. Therefore, we evaluated algorithms for multi-class classification of three diagnostic groups: patients with probable Alzheimer's disease...... of aging). The best performing algorithm yielded an accuracy of 63.0% and an area under the receiver-operating-characteristic curve (AUC) of 78.8%. In general, the best performances were achieved using feature extraction based on voxel-based morphometry or a combination of features that included volume......Abstract Algorithms for computer-aided diagnosis of dementia based on structural MRI have demonstrated high performance in the literature, but are difficult to compare as different data sets and methodology were used for evaluation. In addition, it is unclear how the algorithms would perform...

Adrenal cavernous hemangioma: MRI, CT, and US appearance

International Nuclear Information System (INIS)

Marotti, M.; Sucic, Z.; Krolo, I.; Dimanovski, J.; Klaric, R.; Ferencic, Z.; Karapanda, N.; Babic, N.; Pavlekovic, K.

1997-01-01

Two cases of rare adrenal cavernous hemangiomas are reported, one imaged with conventional X-ray techniques, US, CT, and MRI, and the other with US and CT. The CT technique clearly demonstrated calcifications and the internal structure of the lesions in both cases and peripheral rim enhancement on the postcontrast scan in one patient. Although MRI demonstrated accurately the complex nature of the lesion, the inability to visualize the calcified areas do not allow to make a specific histologic diagnosis. (orig.). With 8 figs

Imaging of the myocardium using {sup 18}F-FDG-PET/MRI

Energy Technology Data Exchange (ETDEWEB)

Ferda, Jiří, E-mail: ferda@fnplzen.cz [Clinic of the Imaging Methods, University Hospital Plzen, Alej Svobody 80, 304 60 Plzeň (Czech Republic); Hromádka, Milan, E-mail: hromadkam@fnplzen.cz [Department of Cardiology, University Hospital Plzen, Alej Svobody 80, 304 60 Plzeň (Czech Republic); Baxa, Jan, E-mail: baxaj@fnplzen.cz [Clinic of the Imaging Methods, University Hospital Plzen, Alej Svobody 80, 304 60 Plzeň (Czech Republic)

2016-10-15

Highlights: • The natural combination of the metabolic and structural information is the most important strenghtof myocardial PET/MRI. • Metabolic conversion to glycolysis is needed in the assesment ov the viable myocardium. • Metabolic conversion to the fatty acid metabolism is the crucial in the assesment of the ischemic memory and myocardial inflammation. - Abstract: The introduction of the integrated hybrid PET/MRI equipment creates the possibility to perform PET and MRI simultaneously. Depending on the clinical question, the metabolic conversion to glycolytic activity or beta-oxidation is performed before the application of FDG. Since FDG aids to evaluate the energetic metabolism of the myocytes and myocardial MRI reaches the imaging capabilities of perfusion and tissue characterization in the daily routine, FDG-PET/MRI looks to be a promising method of PET/MRI exploitation in cardiac imaging. When myocardial FDG uptake should be evaluated in association with the perfusion distribution, the cross-evaluation of FDG accumulation distribution and perfusion distribution pattern is necessary. The different scenarios may be used in the assessment of myocardium, the conversion to glycolytic activity is used in the imaging of the viable myocardium, but the glycolytic activity suppression might be used in the indications of the identification of injured myocardium by ischemia or inflammation. FDG-PET/MRI might aid to answer the clinical tasks according to the structure, current function and possibilities to improve the function in ischemic heart disease or to display the extent or activity of myocardial inflammation in sarcoidosis. The tight coupling between metabolism, perfusion and contractile function offers an opportunity for the simultaneous assessment of cardiac performance using one imaging modality.

Breast MRI: EUSOBI recommendations for women's information

NARCIS (Netherlands)

Mann, R.M.; Balleyguier, C.; Baltzer, P.A.; Bick, U.; Colin, C.; Cornford, E.; Evans, A.; Fallenberg, E.; Forrai, G.; Fuchsjager, M.H.; Gilbert, F.J.; Helbich, T.H.; Heywang-Kobrunner, S.H.; Camps-Herrero, J.; Kuhl, C.K.; Martincich, L.; Pediconi, F.; Panizza, P.; Pina, L.J.; Pijnappel, R.M.; Pinker-Domenig, K.; Skaane, P.; Sardanelli, F.; Imaging, w.l.r.b.E.D.-T.E.B.C.C. European Societ

2015-01-01

This paper summarizes information about breast MRI to be provided to women and referring physicians. After listing contraindications, procedure details are described, stressing the need for correct scheduling and not moving during the examination. The structured report including BI-RADS(R)

Breast MRI : EUSOBI recommendations for women's information

NARCIS (Netherlands)

Mann, Ritse M.; Balleyguier, Corinne; Baltzer, Pascal A.; Bick, Ulrich; Colin, Catherine; Cornford, Eleanor; Evans, Andrew; Fallenberg, Eva; Forrai, Gabor; Fuchsjaeger, Michael H.; Gilbert, Fiona J.; Helbich, Thomas H.; Heywang-Koebrunner, Sylvia H.; Camps-Herrero, Julia; Kuhl, Christiane K.; Martincich, Laura; Pediconi, Federica; Panizza, Pietro; Pina, Luis J.; Pijnappel, Ruud M.; Pinker-Domenig, Katja; Skaane, Per; Sardanelli, Francesco

2015-01-01

This paper summarizes information about breast MRI to be provided to women and referring physicians. After listing contraindications, procedure details are described, stressing the need for correct scheduling and not moving during the examination. The structured report including BI-RADSA (R)

Assessment of ameloblastomas using MRI and dynamic contrast-enhanced MRI

International Nuclear Information System (INIS)

Asaumi, Jun-ichi; Hisatomi, Miki; Yanagi, Yoshinobu; Matsuzaki, Hidenobu; Choi, Yong Suk; Kawai, Noriko; Konouchi, Hironobu; Kishi, Kanji

2005-01-01

We retrospectively evaluated magnetic resonance images (MRI) and dynamic contrast-enhanced MRI (DCE-MRI) of ameloblastomas. MRI and DCE-MRI were performed for 10 ameloblastomas. We obtained the following results from the MRI and DCE-MRI. (a) Ameloblastomas can be divided into solid and cystic portions on the basis of MR signal intensities. (b) Ameloblastomas show a predilection for intermediate signal intensity on T1WI, high signal intensity on T2WI, and well enhancement in the solid portion; they also show a homogeneous intermediate signal intensity on T1WI and homogeneous high signal intensity on T2WI, and no enhancement in the cystic portion. (c) The mural nodule or thick wall can be detected in ameloblastomas lesions. (d) CI curves of ameloblastomas show two patterns: the first pattern increases, reaches a plateau at 100-300 s, then sustains the plateau or decreases gradually to 600-900 s, while the other increases relatively rapidly, reaches a plateau at 90-120 s, then decreases relatively rapidly to 300 s, and decreases gradually thereafter. There was no difference in the CI curve patterns among primary and recurrent cases, a case with glandular odontogenic tumor in ameloblastoma or among histopathological types such as plexiform, follicular, mixed, desmoplastic, and unicystic type

Neonatal brain structure on MRI and diffusion tensor imaging, sex, and neurodevelopment in very-low-birthweight preterm children.

Science.gov (United States)

Rose, Jessica; Butler, Erin E; Lamont, Lauren E; Barnes, Patrick D; Atlas, Scott W; Stevenson, David K

2009-07-01

The neurological basis of an increased incidence of cerebral palsy (CP) in preterm males is unknown. This study examined neonatal brain structure on magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) at term-equivalent age, sex, and neurodevelopment at 1 year 6 months on the basis of the Amiel-Tison neurological examination, Gross Motor Function Classification System, and Bayley Scales of Infant Development in 78 very-low-birthweight preterm children (41 males, 37 females; mean gestational age 27.6 wks, SD 2.5; mean birthweight 1021 g, SD 339). Brain abnormalities on MRI and DTI were not different between males and females except in the splenium of the corpus callosum, where males had lower DTI fractional anisotropy (p=0.025) and a higher apparent diffusion coefficient (p=0.013), indicating delayed splenium development. In the 26 infants who were at higher risk on the basis of DTI, males had more abnormalities on MRI (p=0.034) and had lower fractional anisotropy and a higher apparent diffusion coefficient in the splenium (p=0.049; p=0.025) and right posterior limb of the internal capsule (PLIC; p=0.003; p=0.033). Abnormal neurodevelopment was more common in males (n=9) than in females (n=2; p=0.036). Children with abnormal neurodevelopment had more abnormalities on MRI (p=0.014) and reduced splenium and right PLIC fractional anisotropy (p=0.001; p=0.035). In children with abnormal neurodevelopment, right PLIC fractional anisotropy was lower than left (p=0.035), whereas in those with normal neurodevelopment right PLIC fractional anisotropy was higher than left (p=0.001). Right PLIC fractional anisotropy correlated to neurodevelopment (rho=0.371, p=0.002). Logistic regression predicted neurodevelopment with 94% accuracy; only right PLIC fractional anisotropy was a significant logistic coefficient. Results indicate that the higher incidence of abnormal neurodevelopment in preterm males relates to greater incidence and severity of brain abnormalities

Multiparametric and molecular imaging of breast tumors with MRI and PET/MRI

International Nuclear Information System (INIS)

Pinker, K.; Marino, M.A.; Meyer-Baese, A.; Helbich, T.H.

2016-01-01

Magnetic resonance imaging (MRI) of the breast is an indispensable tool in breast imaging for many indications. Several functional parameters with MRI and positron emission tomography (PET) have been assessed for imaging of breast tumors and their combined application is defined as multiparametric imaging. Available data suggest that multiparametric imaging using different functional MRI and PET parameters can provide detailed information about the hallmarks of cancer and may provide additional specificity. Multiparametric and molecular imaging of the breast comprises established MRI parameters, such as dynamic contrast-enhanced MRI, diffusion-weighted imaging (DWI), MR proton spectroscopy ( 1 H-MRSI) as well as combinations of radiological and MRI techniques (e.g. PET/CT and PET/MRI) using radiotracers, such as fluorodeoxyglucose (FDG). Multiparametric and molecular imaging of the breast can be performed at different field-strengths (range 1.5-7 T). Emerging parameters comprise novel promising techniques, such as sodium imaging ( 23 Na MRI), phosphorus spectroscopy ( 31 P-MRSI), chemical exchange saturation transfer (CEST) imaging, blood oxygen level-dependent (BOLD) and hyperpolarized MRI as well as various specific radiotracers. Multiparametric and molecular imaging has multiple applications in breast imaging. Multiparametric and molecular imaging of the breast is an evolving field that will enable improved detection, characterization, staging and monitoring for personalized medicine in breast cancer. (orig.) [de

Chest MRI

Science.gov (United States)

... resonance imaging - chest; NMR - chest; MRI of the thorax; Thoracic MRI Patient Instructions ... Gotway MB, Panse PM, Gruden JF, Elicker BM. Thoracic radiology. In: Broaddus VC, Mason RJ, Ernst JD, et ...

MRI in psychiatry

International Nuclear Information System (INIS)

Mulert, Christoph; Shenton, Martha E.

2014-01-01

This is the first comprehensive textbook on the use of MRI in psychiatry covering imaging techniques, brain systems and a review of findings in different psychiatric disorders. The book is divided into three sections, the first of which covers in detail all the major MRI-based methodological approaches available today, including fMRI, EEG-fMRI, DTI, and MR spectroscopy. In addition, the role of MRI in imaging genetics and combined brain stimulation and imaging is carefully explained. The second section provides an overview of the different brain systems that are relevant for psychiatric disorders, including the systems for perception, emotion, cognition, and reward. The final part of the book presents the MRI findings that are obtained in all the major psychiatric disorders using the previously discussed techniques. Numerous carefully chosen images support the informative text, making this an ideal reference work for all practitioners and trainees with an interest in this flourishing field.

MRI in psychiatry

Energy Technology Data Exchange (ETDEWEB)

Mulert, Christoph [UKE, Hamburg (Germany). Psychiatry Neuroimaging Branch; Shenton, Martha E. (ed.) [Harvard Medical School, Boston, MA (United States). Dept. of Psychiatry and Radiology

2014-07-01

This is the first comprehensive textbook on the use of MRI in psychiatry covering imaging techniques, brain systems and a review of findings in different psychiatric disorders. The book is divided into three sections, the first of which covers in detail all the major MRI-based methodological approaches available today, including fMRI, EEG-fMRI, DTI, and MR spectroscopy. In addition, the role of MRI in imaging genetics and combined brain stimulation and imaging is carefully explained. The second section provides an overview of the different brain systems that are relevant for psychiatric disorders, including the systems for perception, emotion, cognition, and reward. The final part of the book presents the MRI findings that are obtained in all the major psychiatric disorders using the previously discussed techniques. Numerous carefully chosen images support the informative text, making this an ideal reference work for all practitioners and trainees with an interest in this flourishing field.

Research progress on neural mechanisms of primary insomnia by MRI

Directory of Open Access Journals (Sweden)

Man WANG

2018-04-01

Full Text Available In recent years, more and more researches focused on the neural mechanism of primary insomnia (PI, especially with the development and application of MRI, and researches of brain structure and function related with primary insomnia were more and more in-depth. According to the hyperarousal hypothesis, there are abnormal structure, function and metabolism under certain brain regions of the cortex and subcortex of primary insomnia patients, including amygdala, hippocampus, cingulate gyrus, insular lobe, frontal lobe and parietal lobe. This paper reviewed the research progress of neural mechanisms of primary insomnia by using MRI. DOI: 10.3969/j.issn.1672-6731.2018.03.003

[Fusion of MRI, fMRI and intraoperative MRI data. Methods and clinical significance exemplified by neurosurgical interventions].

Science.gov (United States)

Moche, M; Busse, H; Dannenberg, C; Schulz, T; Schmitgen, A; Trantakis, C; Winkler, D; Schmidt, F; Kahn, T

2001-11-01

The aim of this work was to realize and clinically evaluate an image fusion platform for the integration of preoperative MRI and fMRI data into the intraoperative images of an interventional MRI system with a focus on neurosurgical procedures. A vertically open 0.5 T MRI scanner was equipped with a dedicated navigation system enabling the registration of additional imaging modalities (MRI, fMRI, CT) with the intraoperatively acquired data sets. These merged image data served as the basis for interventional planning and multimodal navigation. So far, the system has been used in 70 neurosurgical interventions (13 of which involved image data fusion--requiring 15 minutes extra time). The augmented navigation system is characterized by a higher frame rate and a higher image quality as compared to the system-integrated navigation based on continuously acquired (near) real time images. Patient movement and tissue shifts can be immediately detected by monitoring the morphological differences between both navigation scenes. The multimodal image fusion allowed a refined navigation planning especially for the resection of deeply seated brain lesions or pathologies close to eloquent areas. Augmented intraoperative orientation and instrument guidance improve the safety and accuracy of neurosurgical interventions.

Diagnostic value of MRI in meniscus injury. Comparison of MRI and arthrography

International Nuclear Information System (INIS)

Iso, Yoshinori; Nozaki, Hiroyuki; Emoto, Mari; Miyairi, Taro; Hirata, Aya; Hirasawa, Seiichi; Suguro, Toru; Igata, Atsuomi; Kudo, Yukihiko.

1995-01-01

Magnetic resonance imaging (MRI) and arthrography were performed on 90 knees to compare the diagnostic value for meniscus injury with these techniques. The diagnostic accuracy of MRI and arthrography was 89.1% and 87.1%, respectively. Imaging of the medial meniscus was somewhat better with arthrography, and delineation of the lateral meniscus was somewhat better with MRI. MRI was superior in diagnoses of horizontal and degenerative lacerations, but showed the shape of the injuries less clearly than arthrography. The diagnostic accuracy of MRI decreased with the age of the patients and was inferior to arthrography for patients in their forties or older. In conclusion, MRI is a less invasive approach with high diagnostic accuracy for meniscus injury and is a promising substitute for arthrography. (author)

Cost-effectiveness of EOB-MRI for Hepatocellular Carcinoma in Japan.

Science.gov (United States)

Nishie, Akihiro; Goshima, Satoshi; Haradome, Hiroki; Hatano, Etsuro; Imai, Yasuharu; Kudo, Masatoshi; Matsuda, Masanori; Motosugi, Utaroh; Saitoh, Satoshi; Yoshimitsu, Kengo; Crawford, Bruce; Kruger, Eliza; Ball, Graeme; Honda, Hiroshi

2017-04-01

The objective of the study was to evaluate the cost-effectiveness of gadoxetic acid-enhanced magnetic resonance imaging (EOB-MRI) in the diagnosis and treatment of hepatocellular carcinoma (HCC) in Japan compared with extracellular contrast media-enhanced MRI (ECCM-MRI) and contrast media-enhanced computed tomography (CE-CT) scanning. A 6-stage Markov model was developed to estimate lifetime direct costs and clinical outcomes associated with EOB-MRI. Diagnostic sensitivity and specificity, along with clinical data on HCC survival, recurrence, treatment patterns, costs, and health state utility values, were derived from predominantly Japanese publications. Parameters unavailable from publications were estimated in a Delphi panel of Japanese clinical experts who also confirmed the structure and overall approach of the model. Sensitivity analyses, including one-way, probabilistic, and scenario analyses, were conducted to account for uncertainty in the results. Over a lifetime horizon, EOB-MRI was associated with lower direct costs (¥2,174,869) and generated a greater number of quality-adjusted life years (QALYs) (9.502) than either ECCM-MRI (¥2,365,421, 9.303 QALYs) or CE-CT (¥2,482,608, 9.215 QALYs). EOB-MRI was superior to the other diagnostic strategies considered, and this finding was robust over sensitivity and scenario analyses. A majority of the direct costs associated with HCC in Japan were found to be costs of treatment. The model results revealed the superior cost-effectiveness of the EOB-MRI diagnostic strategy compared with ECCM-MRI and CE-CT. EOB-MRI could be the first-choice imaging modality for medical care of HCC among patients with hepatitis or liver cirrhosis in Japan. Widespread implementation of EOB-MRI could reduce health care expenditures, particularly downstream treatment costs, associated with HCC. Copyright © 2017 Elsevier HS Journals, Inc. All rights reserved.

A Dictionary Learning Approach for Signal Sampling in Task-Based fMRI for Reduction of Big Data

Science.gov (United States)

Ge, Bao; Li, Xiang; Jiang, Xi; Sun, Yifei; Liu, Tianming

2018-01-01

The exponential growth of fMRI big data offers researchers an unprecedented opportunity to explore functional brain networks. However, this opportunity has not been fully explored yet due to the lack of effective and efficient tools for handling such fMRI big data. One major challenge is that computing capabilities still lag behind the growth of large-scale fMRI databases, e.g., it takes many days to perform dictionary learning and sparse coding of whole-brain fMRI data for an fMRI database of average size. Therefore, how to reduce the data size but without losing important information becomes a more and more pressing issue. To address this problem, we propose a signal sampling approach for significant fMRI data reduction before performing structurally-guided dictionary learning and sparse coding of whole brain's fMRI data. We compared the proposed structurally guided sampling method with no sampling, random sampling and uniform sampling schemes, and experiments on the Human Connectome Project (HCP) task fMRI data demonstrated that the proposed method can achieve more than 15 times speed-up without sacrificing the accuracy in identifying task-evoked functional brain networks. PMID:29706880

A Dictionary Learning Approach for Signal Sampling in Task-Based fMRI for Reduction of Big Data.

Science.gov (United States)

Ge, Bao; Li, Xiang; Jiang, Xi; Sun, Yifei; Liu, Tianming

2018-01-01

The exponential growth of fMRI big data offers researchers an unprecedented opportunity to explore functional brain networks. However, this opportunity has not been fully explored yet due to the lack of effective and efficient tools for handling such fMRI big data. One major challenge is that computing capabilities still lag behind the growth of large-scale fMRI databases, e.g., it takes many days to perform dictionary learning and sparse coding of whole-brain fMRI data for an fMRI database of average size. Therefore, how to reduce the data size but without losing important information becomes a more and more pressing issue. To address this problem, we propose a signal sampling approach for significant fMRI data reduction before performing structurally-guided dictionary learning and sparse coding of whole brain's fMRI data. We compared the proposed structurally guided sampling method with no sampling, random sampling and uniform sampling schemes, and experiments on the Human Connectome Project (HCP) task fMRI data demonstrated that the proposed method can achieve more than 15 times speed-up without sacrificing the accuracy in identifying task-evoked functional brain networks.

7T MRI in focal epilepsy with unrevealing conventional field strength imaging.

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De Ciantis, Alessio; Barba, Carmen; Tassi, Laura; Cosottini, Mirco; Tosetti, Michela; Costagli, Mauro; Bramerio, Manuela; Bartolini, Emanuele; Biagi, Laura; Cossu, Massimo; Pelliccia, Veronica; Symms, Mark R; Guerrini, Renzo

2016-03-01

To assess the diagnostic yield of 7T magnetic resonance imaging (MRI) in detecting and characterizing structural lesions in patients with intractable focal epilepsy and unrevealing conventional (1.5 or 3T) MRI. We conducted an observational clinical imaging study on 21 patients (17 adults and 4 children) with intractable focal epilepsy, exhibiting clinical and electroencephalographic features consistent with a single seizure-onset zone (SOZ) and unrevealing conventional MRI. Patients were enrolled at two tertiary epilepsy surgery centers and imaged at 7T, including whole brain (three-dimensional [3D] T1 -weighted [T1W] fast-spoiled gradient echo (FSPGR), 3D susceptibility-weighted angiography [SWAN], 3D fluid-attenuated inversion recovery [FLAIR]) and targeted imaging (2D T2*-weighted dual-echo gradient-recalled echo [GRE] and 2D gray-white matter tissue border enhancement [TBE] fast spin echo inversion recovery [FSE-IR]). MRI studies at 1.5 or 3T deemed unrevealing at the referral center were reviewed by three experts in epilepsy imaging. Reviewers were provided information regarding the suspected localization of the SOZ. The same team subsequently reviewed 7T images. Agreement in imaging interpretation was reached through consensus-based discussions based on visual identification of structural abnormalities and their likely correlation with clinical and electrographic data. 7T MRI revealed structural lesions in 6 (29%) of 21 patients. The diagnostic gain in detection was obtained using GRE and FLAIR images. Four of the six patients with abnormal 7T underwent epilepsy surgery. Histopathology revealed focal cortical dysplasia (FCD) in all. In the remaining 15 patients (71%), 7T MRI remained unrevealing; 4 of the patients underwent epilepsy surgery and histopathologic evaluation revealed gliosis. 7T MRI improves detection of epileptogenic FCD that is not visible at conventional field strengths. A dedicated protocol including whole brain FLAIR and GRE images at 7T

Direct evidence of intra- and interhemispheric corticomotor network degeneration in amyotrophic lateral sclerosis: an automated MRI structural connectivity study.

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Rose, Stephen; Pannek, Kerstin; Bell, Christopher; Baumann, Fusun; Hutchinson, Nicole; Coulthard, Alan; McCombe, Pamela; Henderson, Robert

2012-02-01

Although the pathogenesis of amyotrophic lateral sclerosis (ALS) is uncertain, there is mounting neuroimaging evidence to suggest a mechanism involving the degeneration of multiple white matter (WM) motor and extramotor neural networks. This insight has been achieved, in part, by using MRI Diffusion Tensor Imaging (DTI) and the voxelwise analysis of anisotropy indices, along with DTI tractography to determine which specific motor pathways are involved with ALS pathology. Automated MRI structural connectivity analyses, which probe WM connections linking various functionally discrete cortical regions, have the potential to provide novel information about degenerative processes within multiple white matter (WM) pathways. Our hypothesis is that measures of altered intra- and interhemispheric structural connectivity of the primary motor and somatosensory cortex will provide an improved assessment of corticomotor involvement in ALS. To test this hypothesis, we acquired High Angular Resolution Diffusion Imaging (HARDI) scans along with high resolution structural images (sMRI) on 15 patients with clinical evidence of upper and lower motor neuron involvement, and 20 matched control participants. Whole brain probabilistic tractography was applied to define specific WM pathways connecting discrete corticomotor targets generated from anatomical parcellation of sMRI of the brain. The integrity of these connections was interrogated by comparing the mean fractional anisotropy (FA) derived for each WM pathway. To assist in the interpretation of results, we measured the reproducibility of the FA summary measures over time (6months) in control participants. We also incorporated into our analysis pipeline the evaluation and replacement of outlier voxels due to head motion and physiological noise. When assessing corticomotor connectivity, we found a significant reduction in mean FA within a number of intra- and interhemispheric motor pathways in ALS patients. The abnormal

Preoperative differential diagnosis of adnexal lesions: Double contrast-MRI

International Nuclear Information System (INIS)

Reuter, M.; Steffens, J.C.; Schueppler, U.; Muhle, C.; Brinkmann, G.; Kohl, G.; Weisner, D.; Luettges, J.; Spielmann, R.P.; Heller, M.

1996-01-01

46 patients with benign (n=42) and malignant (n=4) cystic adnexal tumours underwent MRI of the pelvis. Transaxial and coronal images were acquired using conventional T 1 - and T 2 -weighted SE-sequences after oral administration of superparamagnetic iron oxide particles (Ferristene). Additional T 1 -weighted SE-images were obtained immediately following gadoliamide (Gd DTPA-BMA) injection. MRI correctly classified the four malignant lesions, whereas nine histologically benign lesions were misdiagnosed as malignant. Intravenous contrast yielded a superior delineation of intratumoural architecture. Due to exclusion of solid structures, MRI with oral and i.v. contrast enables to dismiss suspected malignity in cystic adnexal lesions. Because of the non-specificity of the macroscopic criteria of dignity, the MR diagnosis 'malignity' is of limited value. (orig./MG) [de

Comparison of MRI-based and CT/MRI fusion-based postimplant dosimetric analysis of prostate brachytherapy

International Nuclear Information System (INIS)

Tanaka, Osamu; Hayashi, Shinya; Matsuo, Masayuki; Sakurai, Kota; Nakano, Masahiro; Maeda, Sunaho; Kajita, Kimihiro R.T.; Deguchi, Takashi; Hoshi, Hiroaki

2006-01-01

Purpose: The aim of this study was to compare the outcomes between magnetic resonance imaging (MRI)-based and computed tomography (CT)/MRI fusion-based postimplant dosimetry methods in permanent prostate brachytherapy. Methods and Materials: Between October 2004 and March 2006, a total of 52 consecutive patients with prostate cancer were treated by brachytherapy, and postimplant dosimetry was performed using CT/MRI fusion. The accuracy and reproducibility were prospectively compared between MRI-based dosimetry and CT/MRI fusion-based dosimetry based on the dose-volume histogram (DVH) related parameters as recommended by the American Brachytherapy Society. Results: The prostate volume was 15.97 ± 6.17 cc (mean ± SD) in MRI-based dosimetry, and 15.97 ± 6.02 cc in CT/MRI fusion-based dosimetry without statistical difference. The prostate V100 was 94.5% and 93.0% in MRI-based and CT/MRI fusion-based dosimetry, respectively, and the difference was statistically significant (p = 0.002). The prostate D90 was 119.4% and 114.4% in MRI-based and CT/MRI fusion-based dosimetry, respectively, and the difference was statistically significant (p = 0.004). Conclusion: Our current results suggested that, as with fusion images, MR images allowed accurate contouring of the organs, but they tended to overestimate the analysis of postimplant dosimetry in comparison to CT/MRI fusion images. Although this MRI-based dosimetric discrepancy was negligible, MRI-based dosimetry was acceptable and reproducible in comparison to CT-based dosimetry, because the difference between MRI-based and CT/MRI fusion-based results was smaller than that between CT-based and CT/MRI fusion-based results as previously reported

Virtual MRI endoscopy of the intracranial cerebrospinal fluid spaces

International Nuclear Information System (INIS)

Shigematsu, Y.; Korogi, Y.; Hirai, T.; Okuda, T.; Ikushima, I.; Sugahara, T.; Liang, L.; Ge, Y.; Takahashi, M.

1998-01-01

We used constructive interference in steady state (CISS) 3D Fourier transform (3DFT) MRI data sets to obtain three-dimensional (3D) virtual MRI endoscopic views of the intracranial cerebrospinal fluid (CSF) spaces, processing them with a commercially available perspective endoscopic algorithm. We investigated the potential of the intracranial virtual MRI endoscopy applied to visualisation of the pathology in 13 patients with surgically confirmed trigeminal neuralgia (3), hemifacial spasm (3), acoustic neuroma (3), suprasellar germinoma (1), Langerhans cell histiocytosis (1), lateral ventricle nodules (1) and pituitary dwarfism (1). All images were acquired using a 1.5-T imager employing a circular polarised head coil. The CISS-3DFT data sets were transferred to a workstation for processing with the perspective endoscopic algorithm. Postprocessing for virtual MRI endoscopy was possible for all data sets. The lesions in 12 patients, and their complex anatomical relationships with the surrounding structures, were well seen on the 3D images. A small acoustic neuroma in the internal auditory meatus was not seen using virtual endoscopy. Although virtual MRI endoscopy has limitations, it provides 3D images which cannot be acquired using any other procedure. (orig.)

Virtual MRI endoscopy of the intracranial cerebrospinal fluid spaces

Energy Technology Data Exchange (ETDEWEB)

Shigematsu, Y.; Korogi, Y.; Hirai, T. [Kumamoto Univ. (Japan). Dept. of Radiology; Okuda, T.; Ikushima, I.; Sugahara, T.; Liang, L.; Ge, Y.; Takahashi, M.

1998-10-01

We used constructive interference in steady state (CISS) 3D Fourier transform (3DFT) MRI data sets to obtain three-dimensional (3D) virtual MRI endoscopic views of the intracranial cerebrospinal fluid (CSF) spaces, processing them with a commercially available perspective endoscopic algorithm. We investigated the potential of the intracranial virtual MRI endoscopy applied to visualisation of the pathology in 13 patients with surgically confirmed trigeminal neuralgia (3), hemifacial spasm (3), acoustic neuroma (3), suprasellar germinoma (1), Langerhans cell histiocytosis (1), lateral ventricle nodules (1) and pituitary dwarfism (1). All images were acquired using a 1.5-T imager employing a circular polarised head coil. The CISS-3DFT data sets were transferred to a workstation for processing with the perspective endoscopic algorithm. Postprocessing for virtual MRI endoscopy was possible for all data sets. The lesions in 12 patients, and their complex anatomical relationships with the surrounding structures, were well seen on the 3D images. A small acoustic neuroma in the internal auditory meatus was not seen using virtual endoscopy. Although virtual MRI endoscopy has limitations, it provides 3D images which cannot be acquired using any other procedure. (orig.) With 6 figs., 16 refs.

A computational atlas of the hippocampal formation using ex vivo, ultra-high resolution MRI: Application to adaptive segmentation of in vivo MRI.

Science.gov (United States)

Iglesias, Juan Eugenio; Augustinack, Jean C; Nguyen, Khoa; Player, Christopher M; Player, Allison; Wright, Michelle; Roy, Nicole; Frosch, Matthew P; McKee, Ann C; Wald, Lawrence L; Fischl, Bruce; Van Leemput, Koen

2015-07-15

Automated analysis of MRI data of the subregions of the hippocampus requires computational atlases built at a higher resolution than those that are typically used in current neuroimaging studies. Here we describe the construction of a statistical atlas of the hippocampal formation at the subregion level using ultra-high resolution, ex vivo MRI. Fifteen autopsy samples were scanned at 0.13 mm isotropic resolution (on average) using customized hardware. The images were manually segmented into 13 different hippocampal substructures using a protocol specifically designed for this study; precise delineations were made possible by the extraordinary resolution of the scans. In addition to the subregions, manual annotations for neighboring structures (e.g., amygdala, cortex) were obtained from a separate dataset of in vivo, T1-weighted MRI scans of the whole brain (1mm resolution). The manual labels from the in vivo and ex vivo data were combined into a single computational atlas of the hippocampal formation with a novel atlas building algorithm based on Bayesian inference. The resulting atlas can be used to automatically segment the hippocampal subregions in structural MRI images, using an algorithm that can analyze multimodal data and adapt to variations in MRI contrast due to differences in acquisition hardware or pulse sequences. The applicability of the atlas, which we are releasing as part of FreeSurfer (version 6.0), is demonstrated with experiments on three different publicly available datasets with different types of MRI contrast. The results show that the atlas and companion segmentation method: 1) can segment T1 and T2 images, as well as their combination, 2) replicate findings on mild cognitive impairment based on high-resolution T2 data, and 3) can discriminate between Alzheimer's disease subjects and elderly controls with 88% accuracy in standard resolution (1mm) T1 data, significantly outperforming the atlas in FreeSurfer version 5.3 (86% accuracy) and

Candidate Biomarkers in Children with Autism Spectrum Disorder: A Review of MRI Studies

Institute of Scientific and Technical Information of China (English)

Dongyun Li; Hans-Otto Karnath; Xiu Xu

2017-01-01

Searching for effective biomarkers is one of the most challenging tasks in the research field of Autism Spectrum Disorder (ASD).Magnetic resonance imaging (MRI) provides a non-invasive and powerful tool for investigating changes in the structure,function,maturation,connectivity,and metabolism of the brain of children with ASD.Here,we review the more recent MRI studies in young children with ASD,aiming to provide candidate biomarkers for the diagnosis of childhood ASD.The review covers structural imaging methods,diffusion tensor imaging,resting-state functional MRI,and magnetic reso nance spectroscopy.Future advances in neuroimaging techniques,as well as cross-disciplinary studies and largescale collaborations will be needed for an integrated approach linking neuroimaging,genetics,and phenotypic data to allow the discovery of new,effective biomarkers.

Short-Term changes on MRI predict long-Term changes on radiography in rheumatoid arthritis

DEFF Research Database (Denmark)

Peterfy, Charles; Strand, Vibeke; Tian, Lu

2017-01-01

Objective In rheumatoid arthritis (RA), MRI provides earlier detection of structural damage than radiography (X-ray) and more sensitive detection of intra-Articular inflammation than clinical examination. This analysis was designed to evaluate the ability of early MRI findings to predict subsequent...

Convergent Findings of Altered Functional and Structural Brain Connectivity in Individuals with High Functioning Autism: A Multimodal MRI Study.

Directory of Open Access Journals (Sweden)

Sophia Mueller

Full Text Available Brain tissue changes in autism spectrum disorders seem to be rather subtle and widespread than anatomically distinct. Therefore a multimodal, whole brain imaging technique appears to be an appropriate approach to investigate whether alterations in white and gray matter integrity relate to consistent changes in functional resting state connectivity in individuals with high functioning autism (HFA. We applied diffusion tensor imaging (DTI, voxel-based morphometry (VBM and resting state functional connectivity magnetic resonance imaging (fcMRI to assess differences in brain structure and function between 12 individuals with HFA (mean age 35.5, SD 11.4, 9 male and 12 healthy controls (mean age 33.3, SD 9.0, 8 male. Psychological measures of empathy and emotionality were obtained and correlated with the most significant DTI, VBM and fcMRI findings. We found three regions of convergent structural and functional differences between HFA participants and controls. The right temporo-parietal junction area and the left frontal lobe showed decreased fractional anisotropy (FA values along with decreased functional connectivity and a trend towards decreased gray matter volume. The bilateral superior temporal gyrus displayed significantly decreased functional connectivity that was accompanied by the strongest trend of gray matter volume decrease in the temporal lobe of HFA individuals. FA decrease in the right temporo-parietal region was correlated with psychological measurements of decreased emotionality. In conclusion, our results indicate common sites of structural and functional alterations in higher order association cortex areas and may therefore provide multimodal imaging support to the long-standing hypothesis of autism as a disorder of impaired higher-order multisensory integration.

ICA-based artifact removal diminishes scan site differences in multi-center resting-state fMRI.

Directory of Open Access Journals (Sweden)

Rogier Alexander Feis

2015-10-01

Full Text Available Resting-state fMRI (R-fMRI has shown considerable promise in providing potential biomarkers for diagnosis, prognosis and drug response across a range of diseases. Incorporating R-fMRI into multi-center studies is becoming increasingly popular, imposing technical challenges on data acquisition and analysis, as fMRI data is particularly sensitive to structured noise resulting from hardware, software and environmental differences. Here, we investigated whether a novel clean up tool for structured noise was capable of reducing center-related R-fMRI differences between healthy subjects.We analyzed 3 Tesla R-fMRI data from 72 subjects, half of whom were scanned with eyes closed in a Philips Achieva system in The Netherlands, and half of whom were scanned with eyes open in a Siemens Trio system in the UK. After pre-statistical processing and individual Independent Component Analysis (ICA, FMRIB’s ICA-based X-noiseifier (FIX was used to remove noise components from the data. GICA and dual regression were run and non-parametric statistics were used to compare spatial maps between groups before and after applying FIX.Large significant differences were found in all resting-state networks between study sites before using FIX, most of which were reduced to non-significant after applying FIX. The between-center difference in the medial/primary visual network, presumably reflecting a between-center difference in protocol, remained statistically different.FIX helps facilitate multi-center R-fMRI research by diminishing structured noise from R-fMRI data. In doing so, it improves combination of existing data from different centers in new settings and comparison of rare diseases and risk genes for which adequate sample size remains a challenge.

Magnetic resonance imaging (MRI) evaluation of developmental delay in pediatric patients.

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Ali, Althaf S; Syed, Naziya P; Murthy, G S N; Nori, Madhavi; Abkari, Anand; Pooja, B K; Venkateswarlu, J

2015-01-01

Developmental delay is defined as significant delay in one or more developmental domains. Magnetic Resonance Imaging (MRI) is the best modality to investigate such patients. Evaluation of a child with developmental delay is important not only because it allows early diagnosis and treatment but also helpful for parental counseling regarding the outcome of their child and to identify any possible risk of recurrence in the siblings. Thus this study was undertaken to evaluate the developmental delay in Indian children which will help the clinicians in providing an estimation of the child's ultimate developmental potential and organize specific treatment requirement and also relieve parental apprehension. To study the prevalence of normal and abnormal MRI in pediatric patients presenting with developmental delay and further categorize the abnormal MRI based on its morphological features. It is a prospective, observational & descriptive study of MRI Brain in 81 paediatric patients (46 Males and 35 Females), aged between three months to 12 years; presenting with developmental delay in Deccan College of Medical Sciences, Hyderabad; over a period of three years (Sept 2011 to Sept 2014). MRI brain was done on 1.5T Siemens Magnetom Essenza & 0.35T Magnetom C with appropriate sequences and planes after making the child sleep/sedated/ anesthetized. Various anatomical structures like Ventricles, Corpus callosum, etc were systematically assessed. The MRI findings were divided into various aetiological subgroups. Normal MRI findings were seen in 32% cases and 68% had abnormal findings of which the proportion of Traumatic/ Neurovascular Diseases, Congenital & Developmental, Metabolic and Degenerative, neoplastic and non specific were 31%, 17%, 10%, 2.5% and 7.5% respectively. The ventricles and white matter mainly the corpus callosum were the most commonly affected anatomical structures. The diagnostic yield was found to be 68% and higher yield was seen in patients presenting with

Diagnostic benefits of presurgical fMRI in patients with brain tumours in the primary sensorimotor cortex

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Wengenroth, Martina; Blatow, M.; Guenther, J. [University of Heidelberg Medical School, Department of Neuroradiology, Heidelberg (Germany); Akbar, M. [University of Heidelberg Medical School, Department of Orthopaedics, Heidelberg (Germany); Tronnier, V.M. [University of Schleswig-Holstein, Department of Neurosurgery, Luebeck (Germany); Stippich, C. [University Hospital Basle, Department of Diagnostic and Interventional Neuroradiology, Basle (Switzerland)

2011-07-15

Reliable imaging of eloquent tumour-adjacent brain areas is necessary for planning function-preserving neurosurgery. This study evaluates the potential diagnostic benefits of presurgical functional magnetic resonance imaging (fMRI) in comparison to a detailed analysis of morphological MRI data. Standardised preoperative functional and structural neuroimaging was performed on 77 patients with rolandic mass lesions at 1.5 Tesla. The central region of both hemispheres was allocated using six morphological and three functional landmarks. fMRI enabled localisation of the motor hand area in 76/77 patients, which was significantly superior to analysis of structural MRI (confident localisation of motor hand area in 66/77 patients; p < 0.002). FMRI provided additional diagnostic information in 96% (tongue representation) and 97% (foot representation) of patients. FMRI-based presurgical risk assessment correlated in 88% with a positive postoperative clinical outcome. Routine presurgical FMRI allows for superior assessment of the spatial relationship between brain tumour and motor cortex compared with a very detailed analysis of structural 3D MRI, thus significantly facilitating the preoperative risk-benefit assessment and function-preserving surgery. The additional imaging time seems justified. FMRI has the potential to reduce postoperative morbidity and therefore hospitalisation time. (orig.)

Differential diagnosis of the signal-compromised lunate in MRI

International Nuclear Information System (INIS)

Schmitt, R.; Christopoulos, G.; Coblenz, G.; Froehner, S.; Brunner, H.; Kalb, K.; Krimmer, H.; Lanz, U.

2005-01-01

Purpose: To define both the underlying pathology and diagnostic criteria in lunates presenting with conspicuous signal pattern in MRI. Materials and Methods: The retrospective evaluation of 2940 MRI examinations revealed 203 patients with signal alterations of the lunate. All MRI examinations were performed on 1.5-Tesla platforms using dedicated surface coils and an intravenous contrast agent. To establish a definitive diagnosis, a total of 252 MRI examinations (49 follow-ups), 22 CT examinations and 4 arthroscopic studies were obtained in addition to the obligatory conventional radiographs. Results: Incorporating all clinical data, radiographs and MRI examinations succeeded in assigning a diagnosis in 136 signal-compromised lunates (67.0%), whereas additional diagnostic procedures or follow-up examinations were required for the definitive diagnosis in 57 cases (33.0%). The most frequent entities were 51 cases of Kienboeck's disease (25.1%), 47 cases of ulnolunate-(triquetral) impaction syndromes (23.2%) and 44 cases of intra-osseous ganglion cysts (21.7%). Other pathologies included 23 degenerative, 19 traumatic and 10 inflammatory changes as well as 9 congenital conditions. For MRI assessment of the altered lunate, the most important parameters were location and morphology as well as involvement of the articular and osseous structures of the carpus. Conclusion: The lunate may be affected by different pathological states of the wrist. In total, only one quarter of the signal-compromised lunate represented Kienboeck's disease. (orig.)

MRI comes of age in RA clinical trials

DEFF Research Database (Denmark)

Peterfy, Charles; Østergaard, Mikkel; Conaghan, Philip G

2013-01-01

meant difficulties in differentiating structural progression using traditional radiographic outcome measures. Magnetic resonance imaging (MRI) has been demonstrated to assess damage more sensitively than radiographs, but importantly it can measure the upstream drivers of erosions and cartilage loss...

Delineation of early brain development from fetuses to infants with diffusion MRI and beyond.

Science.gov (United States)

Ouyang, Minhui; Dubois, Jessica; Yu, Qinlin; Mukherjee, Pratik; Huang, Hao

2018-04-12

Dynamic macrostructural and microstructural changes take place from the mid-fetal stage to 2 years after birth. Delineating brain structural changes during this early developmental period provides new insights into the complicated processes of both typical brain development and the pathological mechanisms underlying various psychiatric and neurological disorders including autism, attention deficit hyperactivity disorder and schizophrenia. Decades of histological studies have identified strong spatial and functional gradients of maturation in human brain gray and white matter. The recent improvements in magnetic resonance imaging (MRI) techniques, especially diffusion MRI (dMRI), relaxometry imaging, and magnetization transfer imaging (MTI) have provided unprecedented opportunities to non-invasively quantify and map the early developmental changes at whole brain and regional levels. Here, we review the recent advances in understanding early brain structural development during the second half of gestation and the first two postnatal years using modern MR techniques. Specifically, we review studies that delineate the emergence and microstructural maturation of white matter tracts, as well as dynamic mapping of inhomogeneous cortical microstructural organization unique to fetuses and infants. These imaging studies converge into maturational curves of MRI measurements that are distinctive across different white matter tracts and cortical regions. Furthermore, contemporary models offering biophysical interpretations of the dMRI-derived measurements are illustrated to infer the underlying microstructural changes. Collectively, this review summarizes findings that contribute to charting spatiotemporally heterogeneous gray and white matter structural development, offering MRI-based biomarkers of typical brain development and setting the stage for understanding aberrant brain development in neurodevelopmental disorders. Copyright © 2018. Published by Elsevier Inc.

MRI grading method for active and chronic spinal changes in spondyloarthritis

International Nuclear Information System (INIS)

Madsen, K.B.; Jurik, A.G.

2010-01-01

Aim: To describe a magnetic resonance imaging (MRI) grading method for both active and chronic spondyloarthritis (SpA) changes in the spine, to test its validity, and compare chronic MRI scores with findings obtained by radiography. Material and methods: A total of 91 patients (41 males; 50 females) with back pain fulfilling the European Spondylarthropathy Study Group (ESSG) criteria for SpA were examined using MRI and radiography of the spine. The mean age was 36.7 years (range 16-51 years) and symptom duration was between 3 and 27 years. The MRI images were assessed for signs of disease activity (bone marrow oedema at the vertebral plates and costo-vertebral joints) and chronic structural changes [syndesmophytes/vertebral fusion, erosion, and fatty marrow deposition (FMD)]. The interobserver agreement was analysed based on 37 examinations. Radiographs were assessed for the presence of shiny corners, vertebral squaring, syndesmophytes/fusion, and erosion. Results: The interobserver agreement for the assessed MRI abnormalities was acceptable, with kappa values between 0.62 and 0.77. A total of 56 patients had SpA-related spinal abnormalities as depicted using MRI. The total chronic MRI score was not significantly related to the radiographic score, mainly because syndesmophytes were difficult to detect by MRI and FMD was only visualized by MRI. However, FMD was significantly related to the total radiographic score and vertebral squaring. Conclusion: The described MRI grading method was reliable for assessing both disease activity and chronic changes. MRI is promising for estimating chronic changes, but cervical radiography may still be needed. FMD seems to be an important sign of chronicity.

MRI grading method for active and chronic spinal changes in spondyloarthritis

Energy Technology Data Exchange (ETDEWEB)

Madsen, K.B. [Department of Radiology, Aarhus University Hospital, Aarhus Sygehus (Denmark); Jurik, A.G., E-mail: anne.jurik@aarhus.rm.d [Department of Radiology, Aarhus University Hospital, Aarhus Sygehus (Denmark)

2010-01-15

Aim: To describe a magnetic resonance imaging (MRI) grading method for both active and chronic spondyloarthritis (SpA) changes in the spine, to test its validity, and compare chronic MRI scores with findings obtained by radiography. Material and methods: A total of 91 patients (41 males; 50 females) with back pain fulfilling the European Spondylarthropathy Study Group (ESSG) criteria for SpA were examined using MRI and radiography of the spine. The mean age was 36.7 years (range 16-51 years) and symptom duration was between 3 and 27 years. The MRI images were assessed for signs of disease activity (bone marrow oedema at the vertebral plates and costo-vertebral joints) and chronic structural changes [syndesmophytes/vertebral fusion, erosion, and fatty marrow deposition (FMD)]. The interobserver agreement was analysed based on 37 examinations. Radiographs were assessed for the presence of shiny corners, vertebral squaring, syndesmophytes/fusion, and erosion. Results: The interobserver agreement for the assessed MRI abnormalities was acceptable, with kappa values between 0.62 and 0.77. A total of 56 patients had SpA-related spinal abnormalities as depicted using MRI. The total chronic MRI score was not significantly related to the radiographic score, mainly because syndesmophytes were difficult to detect by MRI and FMD was only visualized by MRI. However, FMD was significantly related to the total radiographic score and vertebral squaring. Conclusion: The described MRI grading method was reliable for assessing both disease activity and chronic changes. MRI is promising for estimating chronic changes, but cervical radiography may still be needed. FMD seems to be an important sign of chronicity.

IClinfMRI Software for Integrating Functional MRI Techniques in Presurgical Mapping and Clinical Studies.

Science.gov (United States)

Hsu, Ai-Ling; Hou, Ping; Johnson, Jason M; Wu, Changwei W; Noll, Kyle R; Prabhu, Sujit S; Ferguson, Sherise D; Kumar, Vinodh A; Schomer, Donald F; Hazle, John D; Chen, Jyh-Horng; Liu, Ho-Ling

2018-01-01

Task-evoked and resting-state (rs) functional magnetic resonance imaging (fMRI) techniques have been applied to the clinical management of neurological diseases, exemplified by presurgical localization of eloquent cortex, to assist neurosurgeons in maximizing resection while preserving brain functions. In addition, recent studies have recommended incorporating cerebrovascular reactivity (CVR) imaging into clinical fMRI to evaluate the risk of lesion-induced neurovascular uncoupling (NVU). Although each of these imaging techniques possesses its own advantage for presurgical mapping, a specialized clinical software that integrates the three complementary techniques and promptly outputs the analyzed results to radiology and surgical navigation systems in a clinical format is still lacking. We developed the Integrated fMRI for Clinical Research (IClinfMRI) software to facilitate these needs. Beyond the independent processing of task-fMRI, rs-fMRI, and CVR mapping, IClinfMRI encompasses three unique functions: (1) supporting the interactive rs-fMRI mapping while visualizing task-fMRI results (or results from published meta-analysis) as a guidance map, (2) indicating/visualizing the NVU potential on analyzed fMRI maps, and (3) exporting these advanced mapping results in a Digital Imaging and Communications in Medicine (DICOM) format that are ready to export to a picture archiving and communication system (PACS) and a surgical navigation system. In summary, IClinfMRI has the merits of efficiently translating and integrating state-of-the-art imaging techniques for presurgical functional mapping and clinical fMRI studies.

MRI findings in patients with severe trismus following radiotherapy for nasopharyngeal carcinoma

International Nuclear Information System (INIS)

Bhatia, Kunwar S.S.; King, Ann D.; Paunipagar, Bhawan K.; Abrigo, Jill; Ahuja, Anil T.; Vlantis, Alexander C.; Leung, Sing F.

2009-01-01

The aim of the study was to document MRI findings in masticator structures in patients with trismus developing after radiotherapy for nasopharyngeal carcinoma (NPC). MRI neck examinations were reviewed in 35 patients with marked trismus, defined as an interincisal gap of 25 mm or less, post-radiotherapy for NPC. Patients with trismus before treatment, infiltration of masticator structures at the time of trismus, or previous surgery involving the masticator structures were excluded. Sixteen patients had no significant abnormality in their masticator structures (46%). Nineteen patients (54%) had abnormalities comprising radiotherapy-induced masticator muscle fibrosis (n = 19), denervation atrophy of the masticator muscles secondary to mandibular nerve damage (n = 1), mandibular ramus signal abnormalities (n = 5), mandibular condyle sclerosis with or without capsular thickening (n = 5), perimasticator fibrosis extending into the masticator space (n = 3) and inflammation secondary to severe sinusitis extending into the masticator space (n = 2). Nine patients (26%) had more than one type of abnormality. Twenty-two patients (63%) had concomitant skull base osteoradionecrosis which extended into the pterygoid bases in 16 patients (45%). The presence of several MRI abnormalities in the masticator structures of patients with trismus after radiotherapy suggests that trismus is multifactorial. This study advances the understanding of mechanisms behind this debilitating side effect of radiotherapy. (orig.)

Adaptive Analysis of Functional MRI Data

International Nuclear Information System (INIS)

Friman, Ola

2003-01-01

analysis approach. The second use of CCA is found in a novel so-called exploratory analysis method which extracts interesting and representative structures in fMRI data. Functional MRI data sets are large, and exploratory analysis methods are useful for probing the data for unexpected components. It is also shown how drift and trend models adapted to the fMRI data set at hand can be constructed with this new exploratory CCA technique. Compared to traditionally employed drift models, such adaptive drift models better account for the temporal autocorrelation in the data

MRI assessment program

International Nuclear Information System (INIS)

1988-05-01

Usage, cost and efficacy data from the MRI Assessment Program to 30 March 1988 is presented, as a continuation of an earlier analysis. Analysis has been performed on data from 8565 examinations relating to 7997 patients at 4 hospitals. MRI was used mainly for examination of the head and spine. Some details of the follow up studies being conducted on selected patients and disease categories are given. A consensus statement is included which summaries the view of the Technical Committee on the potential applications of MRI in Australia. The MRI unit quench incident at Royal Adelaide Hospital is described. Refs., 10 figs., tabs

Correction of MRI-induced geometric distortions in whole-body small animal PET-MRI

International Nuclear Information System (INIS)

Frohwein, Lynn J.; Schäfers, Klaus P.; Hoerr, Verena; Faber, Cornelius

2015-01-01

Purpose: The fusion of positron emission tomography (PET) and magnetic resonance imaging (MRI) data can be a challenging task in whole-body PET-MRI. The quality of the registration between these two modalities in large field-of-views (FOV) is often degraded by geometric distortions of the MRI data. The distortions at the edges of large FOVs mainly originate from MRI gradient nonlinearities. This work describes a method to measure and correct for these kind of geometric distortions in small animal MRI scanners to improve the registration accuracy of PET and MRI data. Methods: The authors have developed a geometric phantom which allows the measurement of geometric distortions in all spatial axes via control points. These control points are detected semiautomatically in both PET and MRI data with a subpixel accuracy. The spatial transformation between PET and MRI data is determined with these control points via 3D thin-plate splines (3D TPS). The transformation derived from the 3D TPS is finally applied to real MRI mouse data, which were acquired with the same scan parameters used in the phantom data acquisitions. Additionally, the influence of the phantom material on the homogeneity of the magnetic field is determined via field mapping. Results: The spatial shift according to the magnetic field homogeneity caused by the phantom material was determined to a mean of 0.1 mm. The results of the correction show that distortion with a maximum error of 4 mm could be reduced to less than 1 mm with the proposed correction method. Furthermore, the control point-based registration of PET and MRI data showed improved congruence after correction. Conclusions: The developed phantom has been shown to have no considerable negative effect on the homogeneity of the magnetic field. The proposed method yields an appropriate correction of the measured MRI distortion and is able to improve the PET and MRI registration. Furthermore, the method is applicable to whole-body small animal

Correction of MRI-induced geometric distortions in whole-body small animal PET-MRI

Energy Technology Data Exchange (ETDEWEB)

Frohwein, Lynn J., E-mail: frohwein@uni-muenster.de; Schäfers, Klaus P. [European Institute for Molecular Imaging, University of Münster, Münster 48149 (Germany); Hoerr, Verena; Faber, Cornelius [Department of Clinical Radiology, University Hospital of Münster, Münster 48149 (Germany)

2015-07-15

Purpose: The fusion of positron emission tomography (PET) and magnetic resonance imaging (MRI) data can be a challenging task in whole-body PET-MRI. The quality of the registration between these two modalities in large field-of-views (FOV) is often degraded by geometric distortions of the MRI data. The distortions at the edges of large FOVs mainly originate from MRI gradient nonlinearities. This work describes a method to measure and correct for these kind of geometric distortions in small animal MRI scanners to improve the registration accuracy of PET and MRI data. Methods: The authors have developed a geometric phantom which allows the measurement of geometric distortions in all spatial axes via control points. These control points are detected semiautomatically in both PET and MRI data with a subpixel accuracy. The spatial transformation between PET and MRI data is determined with these control points via 3D thin-plate splines (3D TPS). The transformation derived from the 3D TPS is finally applied to real MRI mouse data, which were acquired with the same scan parameters used in the phantom data acquisitions. Additionally, the influence of the phantom material on the homogeneity of the magnetic field is determined via field mapping. Results: The spatial shift according to the magnetic field homogeneity caused by the phantom material was determined to a mean of 0.1 mm. The results of the correction show that distortion with a maximum error of 4 mm could be reduced to less than 1 mm with the proposed correction method. Furthermore, the control point-based registration of PET and MRI data showed improved congruence after correction. Conclusions: The developed phantom has been shown to have no considerable negative effect on the homogeneity of the magnetic field. The proposed method yields an appropriate correction of the measured MRI distortion and is able to improve the PET and MRI registration. Furthermore, the method is applicable to whole-body small animal

The dynamic programming high-order Dynamic Bayesian Networks learning for identifying effective connectivity in human brain from fMRI.

Science.gov (United States)

Dang, Shilpa; Chaudhury, Santanu; Lall, Brejesh; Roy, Prasun Kumar

2017-06-15

Determination of effective connectivity (EC) among brain regions using fMRI is helpful in understanding the underlying neural mechanisms. Dynamic Bayesian Networks (DBNs) are an appropriate class of probabilistic graphical temporal-models that have been used in past to model EC from fMRI, specifically order-one. High-order DBNs (HO-DBNs) have still not been explored for fMRI data. A fundamental problem faced in the structure-learning of HO-DBN is high computational-burden and low accuracy by the existing heuristic search techniques used for EC detection from fMRI. In this paper, we propose using dynamic programming (DP) principle along with integration of properties of scoring-function in a way to reduce search space for structure-learning of HO-DBNs and finally, for identifying EC from fMRI which has not been done yet to the best of our knowledge. The proposed exact search-&-score learning approach HO-DBN-DP is an extension of the technique which was originally devised for learning a BN's structure from static data (Singh and Moore, 2005). The effectiveness in structure-learning is shown on synthetic fMRI dataset. The algorithm reaches globally-optimal solution in appreciably reduced time-complexity than the static counterpart due to integration of properties. The proof of optimality is provided. The results demonstrate that HO-DBN-DP is comparably more accurate and faster than currently used structure-learning algorithms used for identifying EC from fMRI. The real data EC from HO-DBN-DP shows consistency with previous literature than the classical Granger Causality method. Hence, the DP algorithm can be employed for reliable EC estimates from experimental fMRI data. Copyright © 2017 Elsevier B.V. All rights reserved.

Differentiation of periapical granulomas and cysts by using dental MRI: a pilot study.

Science.gov (United States)

Juerchott, Alexander; Pfefferle, Thorsten; Flechtenmacher, Christa; Mente, Johannes; Bendszus, Martin; Heiland, Sabine; Hilgenfeld, Tim

2018-05-17

The purpose of this pilot study was to evaluate whether periapical granulomas can be differentiated from periapical cysts in vivo by using dental magnetic resonance imaging (MRI). Prior to apicoectomy, 11 patients with radiographically confirmed periapical lesions underwent dental MRI, including fat-saturated T2-weighted (T2wFS) images, non-contrast-enhanced T1-weighted images with and without fat saturation (T1w/T1wFS), and contrast-enhanced fat-saturated T1-weighted (T1wFS+C) images. Two independent observers performed structured image analysis of MRI datasets twice. A total of 15 diagnostic MRI criteria were evaluated, and histopathological results (6 granulomas and 5 cysts) were compared with MRI characteristics. Statistical analysis was performed using intraclass correlation coefficient (ICC), Cohen's kappa (κ), Mann-Whitney U-test and Fisher's exact test. Lesion identification and consecutive structured image analysis was possible on T2wFS and T1wFS+C MRI images. A high reproducibility was shown for MRI measurements of the maximum lesion diameter (intraobserver ICC = 0.996/0.998; interobserver ICC = 0.997), for the "peripheral rim" thickness (intraobserver ICC = 0.988/0.984; interobserver ICC = 0.970), and for all non-quantitative MRI criteria (intraobserver-κ = 0.990/0.995; interobserver-κ = 0.988). In accordance with histopathological results, six MRI criteria allowed for a clear differentiation between cysts and granulomas: (1) outer margin of lesion, (2) texture of "peripheral rim" in T1wFS+C, (3) texture of "lesion center" in T2wFS, (4) surrounding tissue involvement in T2wFS, (5) surrounding tissue involvement in T1wFS+C and (6) maximum "peripheral rim" thickness (all: P periapical cysts and granulomas in vivo. Thus, MRI may substantially improve treatment strategies and help to avoid unnecessary surgery in apical periodontitis.

Atlas of regional anatomy of the brain using MRI. With functional correlations

International Nuclear Information System (INIS)

Tamraz, J.C.

2006-01-01

The volume provides a unique review of the essential topographical anatomy of the brain from an MRI perspective, correlating high-quality anatomical plates with the corresponding high-resolution MRI images. The book includes a historical review of brain mapping and an analysis of the essential reference planes used for the study of the human brain. Subsequent chapters provide a detailed review of the sulcal and the gyral anatomy of the human cortex, guiding the reader through an interpretation of the individual brain atlas provided by high-resolution MRI. The relationship between brain structure and function is approached in a topographical fashion with analysis of the necessary imaging methodology and displayed anatomy. The central, perisylvian, mesial temporal and occipital areas receive special attention. Imaging of the core brain structures is included. An extensive coronal atlas concludes the book. (orig.)

Atlas-guided generation of pseudo-CT images for MRI-only and hybrid PET-MRI-guided radiotherapy treatment planning

Science.gov (United States)

Arabi, Hossein; Koutsouvelis, Nikolaos; Rouzaud, Michel; Miralbell, Raymond; Zaidi, Habib

2016-09-01

Magnetic resonance imaging (MRI)-guided attenuation correction (AC) of positron emission tomography (PET) data and/or radiation therapy (RT) treatment planning is challenged by the lack of a direct link between MRI voxel intensities and electron density. Therefore, even if this is not a trivial task, a pseudo-computed tomography (CT) image must be predicted from MRI alone. In this work, we propose a two-step (segmentation and fusion) atlas-based algorithm focusing on bone tissue identification to create a pseudo-CT image from conventional MRI sequences and evaluate its performance against the conventional MRI segmentation technique and a recently proposed multi-atlas approach. The clinical studies consisted of pelvic CT, PET and MRI scans of 12 patients with loco-regionally advanced rectal disease. In the first step, bone segmentation of the target image is optimized through local weighted atlas voting. The obtained bone map is then used to assess the quality of deformed atlases to perform voxel-wise weighted atlas fusion. To evaluate the performance of the method, a leave-one-out cross-validation (LOOCV) scheme was devised to find optimal parameters for the model. Geometric evaluation of the produced pseudo-CT images and quantitative analysis of the accuracy of PET AC were performed. Moreover, a dosimetric evaluation of volumetric modulated arc therapy photon treatment plans calculated using the different pseudo-CT images was carried out and compared to those produced using CT images serving as references. The pseudo-CT images produced using the proposed method exhibit bone identification accuracy of 0.89 based on the Dice similarity metric compared to 0.75 achieved by the other atlas-based method. The superior bone extraction resulted in a mean standard uptake value bias of  -1.5  ±  5.0% (mean  ±  SD) in bony structures compared to  -19.9  ±  11.8% and  -8.1  ±  8.2% achieved by MRI segmentation-based (water

MRI of normal fetal brain development

International Nuclear Information System (INIS)

Prayer, Daniela; Kasprian, Gregor; Krampl, Elisabeth; Ulm, Barbara; Witzani, Linde; Prayer, Lucas; Brugger, Peter C.

2006-01-01

Normal fetal brain maturation can be studied by in vivo magnetic resonance imaging (MRI) from the 18th gestational week (GW) to term, and relies primarily on T2-weighted and diffusion-weighted (DW) sequences. These maturational changes must be interpreted with a knowledge of the histological background and the temporal course of the respective developmental steps. In addition, MR presentation of developing and transient structures must be considered. Signal changes associated with maturational processes can mainly be ascribed to the following changes in tissue composition and organization, which occur at the histological level: (1) a decrease in water content and increasing cell-density can be recognized as a shortening of T1- and T2-relaxation times, leading to increased T1-weighted and decreased T2-weighted intensity, respectively; (2) the arrangement of microanatomical structures to create a symmetrical or asymmetrical environment, leading to structural differences that may be demonstrated by DW-anisotropy; (3) changes in non-structural qualities, such as the onset of a membrane potential in premyelinating axons. The latter process also influences the appearance of a structure on DW sequences. Thus, we will review the in vivo MR appearance of different maturational states of the fetal brain and relate these maturational states to anatomical, histological, and in vitro MRI data. Then, the development of the cerebral cortex, white matter, temporal lobe, and cerebellum will be reviewed, and the MR appearance of transient structures of the fetal brain will be shown. Emphasis will be placed on the appearance of the different structures with the various sequences. In addition, the possible utility of dynamic fetal sequences in assessing spontaneous fetal movements is discussed

MRI of normal fetal brain development

Energy Technology Data Exchange (ETDEWEB)

Prayer, Daniela [Department of Radiodiagnostics, Medical University of Vienna, Vienna (Austria)]. E-mail: Daniela.prayer@meduniwien.ac.at; Kasprian, Gregor [Department of Radiodiagnostics, Medical University of Vienna, Vienna (Austria); Krampl, Elisabeth [Department of Obstetrics and Gynecology, Medical University of Vienna, Vienna (Austria); Ulm, Barbara [Department of Prenatal Diagnosis, Medical University of Vienna, Vienna (Austria); Witzani, Linde [Department of Radiodiagnostics, Medical University of Vienna, Vienna (Austria); Prayer, Lucas [Diagnosezentrum Urania, Vienna (Austria); Brugger, Peter C. [Center of Anatomy and Cell Biology, Medical University of Vienna, Vienna (Austria)

2006-02-15

Normal fetal brain maturation can be studied by in vivo magnetic resonance imaging (MRI) from the 18th gestational week (GW) to term, and relies primarily on T2-weighted and diffusion-weighted (DW) sequences. These maturational changes must be interpreted with a knowledge of the histological background and the temporal course of the respective developmental steps. In addition, MR presentation of developing and transient structures must be considered. Signal changes associated with maturational processes can mainly be ascribed to the following changes in tissue composition and organization, which occur at the histological level: (1) a decrease in water content and increasing cell-density can be recognized as a shortening of T1- and T2-relaxation times, leading to increased T1-weighted and decreased T2-weighted intensity, respectively; (2) the arrangement of microanatomical structures to create a symmetrical or asymmetrical environment, leading to structural differences that may be demonstrated by DW-anisotropy; (3) changes in non-structural qualities, such as the onset of a membrane potential in premyelinating axons. The latter process also influences the appearance of a structure on DW sequences. Thus, we will review the in vivo MR appearance of different maturational states of the fetal brain and relate these maturational states to anatomical, histological, and in vitro MRI data. Then, the development of the cerebral cortex, white matter, temporal lobe, and cerebellum will be reviewed, and the MR appearance of transient structures of the fetal brain will be shown. Emphasis will be placed on the appearance of the different structures with the various sequences. In addition, the possible utility of dynamic fetal sequences in assessing spontaneous fetal movements is discussed.

Joint Modelling of Structural and Functional Brain Networks

DEFF Research Database (Denmark)

Andersen, Kasper Winther; Herlau, Tue; Mørup, Morten

-parametric Bayesian network model which allows for joint modelling and integration of multiple networks. We demonstrate the model’s ability to detect vertices that share structure across networks jointly in functional MRI (fMRI) and diffusion MRI (dMRI) data. Using two fMRI and dMRI scans per subject, we establish...

Initial tests of a prototype MRI-compatible PET imager

International Nuclear Information System (INIS)

Raylman, Raymond R.; Majewski, Stan; Lemieux, Susan; Velan, S. Sendhil; Kross, Brain; Popov, Vladimir; Smith, Mark F.; Weisenberger, Andrew G.; Wojcik, Randy

2006-01-01

Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI, will allow the correlation of form with function. Our group (a collaboration of West Virginia University and Jefferson Lab) is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode with an active FOV of 5x5x4 cm 3 . Each MRI-PET detector module consists of an array of LSO detector elements (2.5x2.5x15 mm 3 ) coupled through a long fiber optic light guide to a single Hamamatsu flat panel PSPMT. The fiber optic light guide is made of a glued assembly of 2 mm diameter acrylic fibers with a total length of 2.5 m. The use of a light guides allows the PSPMTs to be positioned outside the bore of the 3 T General Electric MRI scanner used in the tests. Photon attenuation in the light guides resulted in an energy resolution of ∼60% FWHM, interaction of the magnetic field with PSPMT further reduced energy resolution to ∼85% FWHM. Despite this effect, excellent multi-plane PET and MRI images of a simple disk phantom were acquired simultaneously. Future work includes improved light guides, optimized magnetic shielding for the PSPMTs, construction of specialized coils to permit high-resolution MRI imaging, and use of the system to perform simultaneous PET and MRI or MR-spectroscopy

Small animal MRI: clinical MRI as an interface to basic biomedical research

International Nuclear Information System (INIS)

Pinkernelle, J.G.; Stelter, L.; Hamm, B.; Teichgraeber, U.

2008-01-01

The demand for highly resolved small animal MRI for the purpose of biomedical research has increased constantly. Dedicated small animal MRI scanners working at ultra high field strengths from 4.7 to 7.0 T and even above are MRI at its best. However, using high resolution RF coils in clinical scanners up to 3.0 T, small animal MRI can achieve highly resolved images showing excellent tissue contrast. In fact, in abundant experimental studies, clinical MRI is used for small animal imaging. Mostly clinical RF coils in the single-loop design are applied. In addition, custom-built RF coils and even gradient inserts are used in a clinical scanner. For the reduction of moving artifacts, special MRI-compatible animal ECG und respiration devices are available. In conclusion, clinical devices offer broad availability, are less expense in combination with good imaging performance and provide a translational nature of imaging results. (orig.)

Functional connectivity analysis of the brain network using resting-state fMRI

International Nuclear Information System (INIS)

Hayashi, Toshihiro

2011-01-01

Spatial patterns of spontaneous fluctuations in blood oxygenation level-dependent (BOLD) signals reflect the underlying neural architecture. The study of the brain network based on these self-organized patterns is termed resting-state functional MRI (fMRI). This review article aims at briefly reviewing a basic concept of this technology and discussing its implications for neuropsychological studies. First, the technical aspects of resting-state fMRI, including signal sources, physiological artifacts, image acquisition, and analytical methods such as seed-based correlation analysis and independent component analysis, are explained, followed by a discussion on the major resting-state networks, including the default mode network. In addition, the structure-function correlation studied using diffuse tensor imaging and resting-state fMRI is briefly discussed. Second, I have discussed the reservations and potential pitfalls of 2 major imaging methods: voxel-based lesion-symptom mapping and task fMRI. Problems encountered with voxel-based lesion-symptom mapping can be overcome by using resting-state fMRI and evaluating undamaged brain networks in patients. Regarding task fMRI in patients, I have also emphasized the importance of evaluating the baseline brain activity because the amplitude of activation in BOLD fMRI is hard to interpret as the same baseline cannot be assumed for both patient and normal groups. (author)

MRI (Magnetic Resonance Imaging)

Science.gov (United States)

... Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Magnetic Resonance Imaging (MRI) is a medical imaging procedure for ...

MRI of pineal region tumours: relationship between tumours and adjacent structures

International Nuclear Information System (INIS)

Satoh, H.; Kurisu, K.

1995-01-01

A variety of tumours may arise in the pineal region; accurate diagnosis is important in the selection of treatment and prognosis. A retrospective analysis of the MRI studies of 25 patients with pathologically proven pineal region tumours was performed, focused on the relationship between the tumour and neighbouring structures. Compression of the tectal plate was classified as expansive or invasive, and compression of the corpus callosum as inferior, anterior or posterior. In 10 of the 14 patients (71 %) with germ cell tumours tectal compression was of the invasive type; 8 patients (57 %) had multiple tumours and in 13 (93 %) the tumour margins were irregular. Teratomas were readily diagnosed because of characteristic heterogeneous signal intensity. Pineal cell tumours were differentiated from germ cell tumours by their rounded shape, solid nature, sharp margins, and expansive type of tectal compression. Meningiomas were characterised by their falcotentorial attachments, posterior callosal compression, and a low-intensity rim on T2-weighted images. Gd-DTPA injection enabled clear demonstration of the site and extent of tumour spread and was useful in differentiating cystic and solid components. The appearances described, while not pathognomonic, are helpful in the differential diagnosis of pineal region tumours, and valuable in planning appropriate treatment. (orig.). With 4 figs., 6 tabs

Superconductive MRI system, FLEXARTTM

International Nuclear Information System (INIS)

Suzuki, Hirokazu; Nishikawa, Mineki; Goro, Takehiko

1994-01-01

Since the establishment of TAMI (Toshiba America MRI Inc.) in 1989, it has been jointly working with Toshiba on developing a new infrastructure for computer and software technologies to be applied to new MRI (magnetic resonance imaging) systems. As a result of these efforts, the first product of a new series of MRI systems has been introduced on the market. Known as FLEXART TM (a newly created word combining FLEXible and ART), this MRI system incorporates a new 32-bit RISC computer and a new controller for pulse sequences and data acquisition. The product concepts of FLEXART TM are high image quality, high patient throughput, and ease of use, all of which are necessary features for an MRI system in the premium mid-field MRI market segment. (author)

Effect of cocaine on structural changes in brain: MRI volumetry using tensor-based morphometry.

Science.gov (United States)

Narayana, Ponnada A; Datta, Sushmita; Tao, Guozhi; Steinberg, Joel L; Moeller, F Gerard

2010-10-01

Magnetic resonance imaging (MRI) was performed in cocaine-dependent subjects to determine the structural changes in brain compared to non-drug using controls. Cocaine-dependent subjects and controls were carefully screened to rule out brain pathology of undetermined origin. Magnetic resonance images were analyzed using tensor-based morphometry (TBM) and voxel-based morphometry (VBM) without and with modulation to adjust for volume changes during normalization. For TBM analysis, unbiased atlases were generated using two different inverse consistent and diffeomorphic nonlinear registration techniques. Two different control groups were used for generating unbiased atlases. Independent of the nonlinear registration technique and normal cohorts used for creating the unbiased atlases, our analysis failed to detect any statistically significant effect of cocaine on brain volumes. These results show that cocaine-dependent subjects do not show differences in regional brain volumes compared to non-drug using controls. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Diagnosis of magnetic resonance imaging (MRI) for blowout fracture. Three advantages of MRI

International Nuclear Information System (INIS)

Nishida, Yasuhiro; Aoki, Yoshiko; Hayashi, Osamu; Kimura, Makiko; Murata, Toyotaka; Ishida, Youichi; Iwami, Tatsuya; Kani, Kazutaka

1999-01-01

Magnetic resonance imaging (MRI) gives a much more detailed picture of the soft tissue than computerized tomography (CT). In blowout fracture cases, it is very easy to observe the incarcerated orbital tissue. We performed MRI in 19 blowout fracture cases. After evaluating the images, we found three advantages of MRI. The first is that even small herniation of the orbital contents can easily be detected because the orbital fatty tissue contrasts well around the other tissues in MRI. The second is that the incarcerated tissues can be clearly differentiated because a clear contrast between the orbital fatty tissue and the extraocular muscle can be seen in MRI. The third is that the running images of the incarcerated muscle belly can be observed because any necessary directional slies can be taken in MRI. These advantages are very important in the diagnosis of blowout fractures. MRI should be employed in blowout fracture cases in addition to CT. (author)

Deep Learning for Brain MRI Segmentation: State of the Art and Future Directions.

Science.gov (United States)

Akkus, Zeynettin; Galimzianova, Alfiia; Hoogi, Assaf; Rubin, Daniel L; Erickson, Bradley J

2017-08-01

Quantitative analysis of brain MRI is routine for many neurological diseases and conditions and relies on accurate segmentation of structures of interest. Deep learning-based segmentation approaches for brain MRI are gaining interest due to their self-learning and generalization ability over large amounts of data. As the deep learning architectures are becoming more mature, they gradually outperform previous state-of-the-art classical machine learning algorithms. This review aims to provide an overview of current deep learning-based segmentation approaches for quantitative brain MRI. First we review the current deep learning architectures used for segmentation of anatomical brain structures and brain lesions. Next, the performance, speed, and properties of deep learning approaches are summarized and discussed. Finally, we provide a critical assessment of the current state and identify likely future developments and trends.

Fe Core–Carbon Shell Nanoparticles as Advanced MRI Contrast Enhancer

Directory of Open Access Journals (Sweden)

Rakesh P. Chaudhary

2017-10-01

Full Text Available The aim of this study is to fabricate a hybrid composite of iron (Fe core–carbon (C shell nanoparticles with enhanced magnetic properties for contrast enhancement in magnetic resonance imaging (MRI. These new classes of magnetic core–shell nanoparticles are synthesized using a one-step top–down approach through the electric plasma discharge generated in the cavitation field in organic solvents by an ultrasonic horn. Transmission electron microscopy (TEM observations revealed the core–shell nanoparticles with 10–85 nm in diameter with excellent dispersibility in water without any agglomeration. TEM showed the structural confirmation of Fe nanoparticles with body centered cubic (bcc crystal structure. Magnetic multi-functional hybrid composites of Fe core–C shell nanoparticles were then evaluated as negative MRI contrast agents, displaying remarkably high transverse relaxivity (r2 of 70 mM−1·S−1 at 7 T. This simple one-step synthesis procedure is highly versatile and produces desired nanoparticles with high efficacy as MRI contrast agents and potential utility in other biomedical applications.

Creatine Deficiency Syndrome could be Missed Easily: A Case Report of Guanidinoacetate Methyltransferase Deficiency Presented with Neurodevelopmental Delay, Seizures, and Behavioral Changes, but Normal Structural MRI.

Science.gov (United States)

Pacheva, Iliyana; Ivanov, Ivan; Penkov, Marin; Kancheva, Daliya; Jordanova, Albena; Ivanova, Mariya

2016-09-01

A case with GAMT deficiency (homozygous c.64dupG mutation) presented with neurodevelopmental delay, rare seizures, behavioral disturbances, and mild hypotonia, posing diagnostic challenges. Metabolic investigations showed low creatinine in plasma and urine (guanidinoacetate couldn't be investigated) and slightly elevated lactate. MRI was normal. Correct diagnosis was possible only after MR spectroscopy was performed at age 5½ years. A homozygous c.64dupG mutation of the GAMT gene was identified in the proband. In conclusion, every case with neurodevelopmental delay or arrest, especially when accompanied by seizures, behavioral impairment, muscle hypotonia or extrapyramidal symptoms should undergo MRI with MR spectroscopy. Normal structural MRI doesn't exclude a creatine deficiency syndrome. Biochemical investigations of guanidinoacetate, creatine, and creatinine in body fluid should be done to diagnose cerebral creatine deficiency syndromes and to specify the deficient enzyme. Thus, a treatable disease will not be missed. © 2016 by the Association of Clinical Scientists, Inc.

Magnetic Resonance Imaging (MRI) Safety

Science.gov (United States)

... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) Safety What is MRI and how ... What is MRI and how does it work? Magnetic resonance imaging, or MRI, is a way of obtaining ...

The usefulness of MRI for detection of the thymus gland in myasthenia gravis

Energy Technology Data Exchange (ETDEWEB)

Hokezu, Youichi; Kaseda, Syun; Arimura, Kimiyoshi; Osame, Mitsuhiro; Baba, Kuniaki (Kagoshima Univ. (Japan). Faculty of Medicine); Ohkubo, Koichi; Hagiwara, Hiroshi

1989-08-01

Seven patients with myasthenia gravis (MG) were examined to find thymus or thymoma employing chest radiographs, computed tomography (CT), pneumomediastinography (PMG), computed tomography after pneumomediastinography (PMG-CT) and magnetic resonance imaging (MRI). X-ray CT examination could reveal thymus only in half out of 6 cases scanned. On the other hand, MRI confirmed thymus or thymoma in 6 out of 7 patients. PMG and PMG-CT confirmed thymus or thymoma clearly in all of the 4 cases studied. PMG and PMG-CT examinations revealed thymus or thymoma more clearly than MRI. MRI is, however, an examination causing no pain to the patients and also more superior to X-ray CT in distinguishing between a thymus and mediastinal fat or vascular structure. In addition, MRI could reveal even capsules in thymoma which were never revealed by X-ray CT. We concluded that MRI could be an alternative method to CT and PMG in detection of thymus or thymoma in MG. (author).

The usefulness of MRI for detection of the thymus gland in myasthenia gravis

International Nuclear Information System (INIS)

Hokezu, Youichi; Kaseda, Syun; Arimura, Kimiyoshi; Osame, Mitsuhiro; Baba, Kuniaki; Ohkubo, Koichi; Hagiwara, Hiroshi.

1989-01-01

Seven patients with myasthenia gravis (MG) were examined to find thymus or thymoma employing chest radiographs, computed tomography (CT), pneumomediastinography (PMG), computed tomography after pneumomediastinography (PMG-CT) and magnetic resonance imaging (MRI). X-ray CT examination could reveal thymus only in half out of 6 cases scanned. On the other hand, MRI confirmed thymus or thymoma in 6 out of 7 patients. PMG and PMG-CT confirmed thymus or thymoma clearly in all of the 4 cases studied. PMG and PMG-CT examinations revealed thymus or thymoma more clearly than MRI. MRI is, however, an examination causing no pain to the patients and also more superior to X-ray CT in distinguishing between a thymus and mediastinal fat or vascular structure. In addition, MRI could reveal even capsules in thymoma which were never revealed by X-ray CT. We concluded that MRI could be an alternative method to CT and PMG in detection of thymus or thymoma in MG. (author)

Cardiac MRI in patients with complex CHD following primary or secondary implantation of MRI-conditional pacemaker system.

Science.gov (United States)

Al-Wakeel, Nadya; O h-Ici, Darach; Schmitt, Katharina R; Messroghli, Daniel R; Riesenkampff, Eugénie; Berger, Felix; Kuehne, Titus; Peters, Bjoern

2016-02-01

In patients with CHD, cardiac MRI is often indicated for functional and anatomical assessment. With the recent introduction of MRI-conditional pacemaker systems, cardiac MRI has become accessible for patients with pacemakers. The present clinical study aims to evaluate safety, susceptibility artefacts, and image reading of cardiac MRI in patients with CHD and MRI-conditional pacemaker systems. Material and methods CHD patients with MRI-conditional pacemaker systems and a clinical need for cardiac MRI were examined with a 1.5-T MRI system. Lead function was tested before and after MRI. Artefacts and image readings were evaluated using a four-point grading scale. A total of nine patients with CHD (mean age 34.0 years, range 19.5-53.6 years) received a total of 11 cardiac MRI examinations. Owing to clinical indications, seven patients had previously been converted from conventional to MRI-conditional pacemaker systems. All MRI examinations were completed without adverse effects. Device testing immediately after MRI and at follow-up showed no alteration of pacemaker device and lead function. Clinical questions could be addressed and answered in all patients. Cardiac MRI can be performed safely with high certainty of diagnosis in CHD patients with MRI-conditional pacemaker systems. In case of clinically indicated lead and box changing, CHD patients with non-MRI-conditional pacemaker systems should be considered for complete conversion to MRI-conditional systems.

MRI of the Chest

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Full Text Available ... affecting the MRI images, these objects can become projectiles within the MRI scanner room and may cause ... MRI has proven valuable in diagnosing a broad range of conditions, including cancer, heart and vascular disease, ...

MRI of the Chest

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Full Text Available ... does not completely surround you. Some newer MRI machines have a larger diameter bore which can be ... size patients or patients with claustrophobia. Other MRI machines are open on the sides (open MRI). Open ...

MRI of the Chest

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Full Text Available ... in the first three to four months of pregnancy unless the potential benefit from the MRI exam ... the MRI Safety page for more information about pregnancy and MRI. If you have claustrophobia (fear of ...

MRI of the Chest

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Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Chest Magnetic resonance imaging (MRI) ... clearer and more detailed than with other imaging methods. This detail makes MRI an invaluable tool in ...

Play the MRI Game

Science.gov (United States)

... Teachers' Questionnaire MRI Play MRI the Magnetic Miracle Game About the game In the MRI imaging technique, strong magnets and ... last will in Paris. Play the Blood Typing Game Try to save some patients and learn about ...

Is fMRI "noise" really noise? Resting state nuisance regressors remove variance with network structure.

Science.gov (United States)

Bright, Molly G; Murphy, Kevin

2015-07-01

Noise correction is a critical step towards accurate mapping of resting state BOLD fMRI connectivity. Noise sources related to head motion or physiology are typically modelled by nuisance regressors, and a generalised linear model is applied to regress out the associated signal variance. In this study, we use independent component analysis (ICA) to characterise the data variance typically discarded in this pre-processing stage in a cohort of 12 healthy volunteers. The signal variance removed by 24, 12, 6, or only 3 head motion parameters demonstrated network structure typically associated with functional connectivity, and certain networks were discernable in the variance extracted by as few as 2 physiologic regressors. Simulated nuisance regressors, unrelated to the true data noise, also removed variance with network structure, indicating that any group of regressors that randomly sample variance may remove highly structured "signal" as well as "noise." Furthermore, to support this we demonstrate that random sampling of the original data variance continues to exhibit robust network structure, even when as few as 10% of the original volumes are considered. Finally, we examine the diminishing returns of increasing the number of nuisance regressors used in pre-processing, showing that excessive use of motion regressors may do little better than chance in removing variance within a functional network. It remains an open challenge to understand the balance between the benefits and confounds of noise correction using nuisance regressors. Copyright © 2015. Published by Elsevier Inc.

Giant cisterna chyli: MRI depiction with gadolinium-DTPA enhancement

International Nuclear Information System (INIS)

Lee, K.C.Y.; Cassar-Pullicino, V.N.

2000-01-01

AIM: To demonstrate the use of MRI with Gadolinium-DTPA enhancement in the diagnosis of giant cisterna chyli. MATERIALS AND METHODS: The study consisted of contrast enhanced MRI with ultrasound and CT correlation in three patients with a giant cisterna chyli. An analysis of the morphology, location and post-contrast MR signal characteristics in relation to time was performed. RESULTS: Cisterna chyli has a characteristic lobulated morphology and location but the unenhanced MRI appearances are not specific. The post-Gadolinium-DTPA MRI appearances are critically dependent on the time elapsed after injection of contrast medium. Within the first 5 min, there is no enhancement at all, but by 10 min there is early layering of contrast medium evident, which by 30 min produces a clear fluid-fluid level. Delayed images at 4-5 h demonstrate a uniform enhancement of the cisternal contents producing a homogeneous intermediate signal. All of these features are best visualized on T1 fast saturation sequences. CONCLUSION: MRI with Gadolinium-DTPA enhancement is valuable in confirming the nature of the lymphatic ducts in the retroperitoneal space and helps to differentiate these normal structures from alternative lesions such as lymphadenopathy and tumour recurrence. Lee, K.C.Y., Cassar-Pullicino, V.N. (2000)

Cumulant expansions for measuring water exchange using diffusion MRI

Science.gov (United States)

Ning, Lipeng; Nilsson, Markus; Lasič, Samo; Westin, Carl-Fredrik; Rathi, Yogesh

2018-02-01

The rate of water exchange across cell membranes is a parameter of biological interest and can be measured by diffusion magnetic resonance imaging (dMRI). In this work, we investigate a stochastic model for the diffusion-and-exchange of water molecules. This model provides a general solution for the temporal evolution of dMRI signal using any type of gradient waveform, thereby generalizing the signal expressions for the Kärger model. Moreover, we also derive a general nth order cumulant expansion of the dMRI signal accounting for water exchange, which has not been explored in earlier studies. Based on this analytical expression, we compute the cumulant expansion for dMRI signals for the special case of single diffusion encoding (SDE) and double diffusion encoding (DDE) sequences. Our results provide a theoretical guideline on optimizing experimental parameters for SDE and DDE sequences, respectively. Moreover, we show that DDE signals are more sensitive to water exchange at short-time scale but provide less attenuation at long-time scale than SDE signals. Our theoretical analysis is also validated using Monte Carlo simulations on synthetic structures.

1.5 T augmented reality navigated interventional MRI: paravertebral sympathetic plexus injections.

Science.gov (United States)

Marker, David R; U Thainual, Paweena; Ungi, Tamas; Flammang, Aaron J; Fichtinger, Gabor; Iordachita, Iulian I; Carrino, John A; Fritz, Jan

2017-01-01

The high contrast resolution and absent ionizing radiation of interventional magnetic resonance imaging (MRI) can be advantageous for paravertebral sympathetic nerve plexus injections. We assessed the feasibility and technical performance of MRI-guided paravertebral sympathetic injections utilizing augmented reality navigation and 1.5 T MRI scanner. A total of 23 bilateral injections of the thoracic (8/23, 35%), lumbar (8/23, 35%), and hypogastric (7/23, 30%) paravertebral sympathetic plexus were prospectively planned in twelve human cadavers using a 1.5 Tesla (T) MRI scanner and augmented reality navigation system. MRI-conditional needles were used. Gadolinium-DTPA-enhanced saline was injected. Outcome variables included the number of control magnetic resonance images, target error of the needle tip, punctures of critical nontarget structures, distribution of the injected fluid, and procedure length. Augmented-reality navigated MRI guidance at 1.5 T provided detailed anatomical visualization for successful targeting of the paravertebral space, needle placement, and perineural paravertebral injections in 46 of 46 targets (100%). A mean of 2 images (range, 1-5 images) were required to control needle placement. Changes of the needle trajectory occurred in 9 of 46 targets (20%) and changes of needle advancement occurred in 6 of 46 targets (13%), which were statistically not related to spinal regions (P = 0.728 and P = 0.86, respectively) and cadaver sizes (P = 0.893 and P = 0.859, respectively). The mean error of the needle tip was 3.9±1.7 mm. There were no punctures of critical nontarget structures. The mean procedure length was 33±12 min. 1.5 T augmented reality-navigated interventional MRI can provide accurate imaging guidance for perineural injections of the thoracic, lumbar, and hypogastric sympathetic plexus.

Fundamental Tongue Motions for Trumpet Playing: A Study Using Cine Magnetic Resonance Imaging (Cine MRI).

Science.gov (United States)

Furuhashi, Hiroko; Chikui, Toru; Inadomi, Daisuke; Shiraishi, Tomoko; Yoshiura, Kazunori

2017-12-01

Though the motions of structures outside the mouth in trumpet performance have been reported, the dynamics of intraoral structures remain unelucidated. This study explored the tongue's movement in trumpet playing using cine magnetic resonance imaging (cine MRI) and demonstrated the effects of intraoral anatomical structures on changes in pitch and dynamics. Cine MRI was applied to 18 trumpet players, who were divided into two groups (7 beginner, 11 advanced) based on their ability to play a certain high note. They were instructed to play a custom-made MRI-compatible simulated trumpet. Pitch-change tasks and dynamics-change tasks were assigned. The positions of the anatomical points and intraoral areas were identified on outlined images, and the changes associated with each task were evaluated. A forward and upward projection of the tongue was observed in the production of higher pitches, and there were no significant differences in all areas. In louder dynamics, a backward and downward bending of the tongue occurred, the tongue area became smaller (pcine MRI that certain tongue movements were associated with each task. Tongue protrusion in the production of higher pitch and bending in louder dynamics can be rationalized using acoustics theory and the movements of anatomical structures. These findings seem to be consistent regardless of the player's proficiency.

Comparison of particle image velocimetry and phase contrast MRI in a patient-specific extracardiac total cavopulmonary connection.

Science.gov (United States)

Kitajima, Hiroumi D; Sundareswaran, Kartik S; Teisseyre, Thomas Z; Astary, Garrett W; Parks, W James; Skrinjar, Oskar; Oshinski, John N; Yoganathan, Ajit P

2008-08-01

Particle image velocimetry (PIV) and phase contrast magnetic resonance imaging (PC-MRI) have not been compared in complex biofluid environments. Such analysis is particularly useful to investigate flow structures in the correction of single ventricle congenital heart defects, where fluid dynamic efficiency is essential. A stereolithographic replica of an extracardiac total cavopulmonary connection (TCPC) is studied using PIV and PC-MRI in a steady flow loop. Volumetric two-component PIV is compared to volumetric three-component PC-MRI at various flow conditions. Similar flow structures are observed in both PIV and PC-MRI, where smooth flow dominates the extracardiac TCPC, and superior vena cava flow is preferential to the right pulmonary artery, while inferior vena cava flow is preferential to the left pulmonary artery. Where three-component velocity is available in PC-MRI studies, some helical flow in the extracardiac TCPC is observed. Vessel cross sections provide an effective means of validation for both experiments, and velocity magnitudes are of the same order. The results highlight similarities to validate flow in a complex patient-specific extracardiac TCPC. Additional information obtained by velocity in three components further describes the complexity of the flow in anatomic structures.

Combined PET/MRI

DEFF Research Database (Denmark)

Bailey, D L; Pichler, B J; Gückel, B

2018-01-01

The 6th annual meeting to address key issues in positron emission tomography (PET)/magnetic resonance imaging (MRI) was held again in Tübingen, Germany, from March 27 to 29, 2017. Over three days of invited plenary lectures, round table discussions and dialogue board deliberations, participants c...... of response to pharmacological interventions and therapies. As such, PET/MRI is a key to advancing medicine and patient care.......The 6th annual meeting to address key issues in positron emission tomography (PET)/magnetic resonance imaging (MRI) was held again in Tübingen, Germany, from March 27 to 29, 2017. Over three days of invited plenary lectures, round table discussions and dialogue board deliberations, participants...... critically assessed the current state of PET/MRI, both clinically and as a research tool, and attempted to chart future directions. The meeting addressed the use of PET/MRI and workflows in oncology, neurosciences, infection, inflammation and chronic pain syndromes, as well as deeper discussions about how...

Magnetic Resonance Imaging (MRI) -- Head

Science.gov (United States)

... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

Fetal MRI and ultrasound of congenital CNS anomalies

International Nuclear Information System (INIS)

Pogledic, I.; Reith, W.; Meyberg-Solomayer, G.

2013-01-01

In the last decade the newest technologies, fetal magnetic resonance imaging (MRI) and 3D ultrasound, have given an insight into the minute structures of the fetal brain. However, without knowledge of the basic developmental processes the imaging is futile. Knowledge of fetal neuroanatomy corresponding to the gestational week is necessary in order to recognize pathological structures. Furthermore, a modern neuroradiologist should be acquainted with the three steps in the formation of the cerebral cortex: proliferation, migration and differentiation of neurons in order to be in a position to suspect that there is a pathology and start recognizing and discovering the abnormalities. The fetal MRI has become an important complementary method to ultrasound especially in cortical malformations when confirmation of the prenatal diagnosis is needed and additional pathologies need to be diagnosed. In this manner these two methods help in parental counseling and treatment planning. (orig.) [de

Humeral avulsion of the anterior shoulder stabilizing structures after anterior shoulder dislocation: demonstration by MRI and MR arthrography

International Nuclear Information System (INIS)

Tirman, P.F.J.; Steinbach, L.S.; Feller, J.F.; Stauffer, A.E.

1996-01-01

Objective. To demonstrate the MRI findings of an anterior shoulder capsular avulsion from the humerus, with or without subscapularis rupture, after anterior dislocation or severe abduction external rotation injury. Design and patients. We retrospectively reviewed the MRI and MR arthrographic examinations of seven patients who were identified at surgery with avulsion of the anterior shoulder stabilizers from the humerus. MRI was correlated with clinical history and surgical results. Results. MRI findings included: inhomogeneity or frank disruption of the anterior capsule at the humeral insertion (all), fluid intensity anterior to the shoulder (six patients), tear of the subscapularis tendon (six patients), dislocation of the biceps tendon (four patients), and a Hill-Sachs deformity (four patients). MR arthrography additionally found extravasation of contrast through the capsular defect (two patients). Conclusions. Our findings suggest that MRI is helpful for diagnosing humeral avulsion of the anterior glenohumeral capsule, especially when a tear of the subscapularis tendon insertion is present. MR arthrography may be of benefit for diagnosing capsular avulsion without associated subscapularis tendon abnormality. (orig.). With 4 figs

MRI of the Chest

Medline Plus

Full Text Available ... or patients with claustrophobia. Other MRI machines are open on the sides (open MRI). Open units are especially helpful for examining larger patients or those with claustrophobia. Newer open MRI units provide very high quality images for ...

Radiation induced currents in MRI RF coils: application to linac/MRI integration

Science.gov (United States)

Burke, B.; Fallone, B. G.; Rathee, S.

2010-02-01

The integration of medical linear accelerators (linac) with magnetic resonance imaging (MRI) systems is advancing the current state of image-guided radiotherapy. The MRI in these integrated units will provide real-time, accurate tumor locations for radiotherapy treatment, thus decreasing geometric margins around tumors and reducing normal tissue damage. In the real-time operation of these integrated systems, the radiofrequency (RF) coils of MRI will be irradiated with radiation pulses from the linac. The effect of pulsed radiation on MRI radio frequency (RF) coils is not known and must be studied. The instantaneous radiation induced current (RIC) in two different MRI RF coils were measured and presented. The frequency spectra of the induced currents were calculated. Some basic characterization of the RIC was also done: isolation of the RF coil component responsible for RIC, dependence of RIC on dose rate, and effect of wax buildup placed on coil on RIC. Both the time and frequency characteristics of the RIC were seen to vary with the MRI RF coil used. The copper windings of the RF coils were isolated as the main source of RIC. A linear dependence on dose rate was seen. The RIC was decreased with wax buildup, suggesting an electronic disequilibrium as the cause of RIC. This study shows a measurable RIC present in MRI RF coils. This unwanted current could be possibly detrimental to the signal to noise ratio in MRI and produce image artifacts.

Tuberculous tenosynovitis of the wrist: MRI findings in three patients

Energy Technology Data Exchange (ETDEWEB)

Sueyoshi, E. [Department of Radiology, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki 852 (Japan); Uetani, M. [Department of Radiology, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki 852 (Japan); Hayashi, K. [Department of Radiology, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki 852 (Japan); Kohzaki, S. [Nagasaki Municipal Hospital, Nagasaki (Japan)

1996-08-01

We report recent MRI findings in patients with tuberculous tenosynovitis of the wrist. Marked synovial thickening around the flexor tendons and fluid in the tendon sheath were clearly shown on MRI. Post-contrast study was useful in distinguishing the thick tenosynovium from the surrounding structures and fluid in the tendon sheath. The well-enhanced tenosynovium was also seen in the carpal tunnel in all cases. On the basis of these findings, we could easily distinguish tenosynovitis from other soft-tissue-mass lesions, such as tumors or infected ganglia. Tuberculous tenosynovitis is often not diagnosed early, and its differentiation from soft tissue tumors may be clinically difficult. MRI, particularly post-contrast study, is useful for early diagnosis of, and planning treatment for, tuberculous tenosynovitis. (orig.). With 3 figs.

Tuberculous tenosynovitis of the wrist: MRI findings in three patients

International Nuclear Information System (INIS)

Sueyoshi, E.; Uetani, M.; Hayashi, K.; Kohzaki, S.

1996-01-01

We report recent MRI findings in patients with tuberculous tenosynovitis of the wrist. Marked synovial thickening around the flexor tendons and fluid in the tendon sheath were clearly shown on MRI. Post-contrast study was useful in distinguishing the thick tenosynovium from the surrounding structures and fluid in the tendon sheath. The well-enhanced tenosynovium was also seen in the carpal tunnel in all cases. On the basis of these findings, we could easily distinguish tenosynovitis from other soft-tissue-mass lesions, such as tumors or infected ganglia. Tuberculous tenosynovitis is often not diagnosed early, and its differentiation from soft tissue tumors may be clinically difficult. MRI, particularly post-contrast study, is useful for early diagnosis of, and planning treatment for, tuberculous tenosynovitis. (orig.). With 3 figs

Persistent post-traumatic headache vs. migraine: an MRI study demonstrating differences in brain structure.

Science.gov (United States)

Schwedt, Todd J; Chong, Catherine D; Peplinski, Jacob; Ross, Katherine; Berisha, Visar

2017-08-22

The majority of individuals with post-traumatic headache have symptoms that are indistinguishable from migraine. The overlap in symptoms amongst these individuals raises the question as to whether post-traumatic headache has a unique pathophysiology or if head trauma triggers migraine. The objective of this study was to compare brain structure in individuals with persistent post-traumatic headache (i.e. headache lasting at least 3 months following a traumatic brain injury) attributed to mild traumatic brain injury to that of individuals with migraine. Twenty-eight individuals with persistent post-traumatic headache attributed to mild traumatic brain injury and 28 individuals with migraine underwent brain magnetic resonance imaging on a 3 T scanner. Regional volumes, cortical thickness, surface area and curvature measurements were calculated from T1-weighted sequences and compared between subject groups using ANCOVA. MRI data from 28 healthy control subjects were used to interpret the differences in brain structure between migraine and persistent post-traumatic headache. Differences in regional volumes, cortical thickness, surface area and brain curvature were identified when comparing the group of individuals with persistent post-traumatic headache to the group with migraine. Structure was different between groups for regions within the right lateral orbitofrontal lobe, left caudal middle frontal lobe, left superior frontal lobe, left precuneus and right supramarginal gyrus (p right lateral orbitofrontal lobe, right supramarginal gyrus, and left superior frontal lobe and no differences when comparing the migraine cohort to healthy controls. In conclusion, persistent post-traumatic headache and migraine are associated with differences in brain structure, perhaps suggesting differences in their underlying pathophysiology. Additional studies are needed to further delineate similarities and differences in brain structure and function that are associated with post

Human brain functional MRI and DTI visualization with virtual reality.

Science.gov (United States)

Chen, Bin; Moreland, John; Zhang, Jingyu

2011-12-01

Magnetic resonance diffusion tensor imaging (DTI) and functional MRI (fMRI) are two active research areas in neuroimaging. DTI is sensitive to the anisotropic diffusion of water exerted by its macromolecular environment and has been shown useful in characterizing structures of ordered tissues such as the brain white matter, myocardium, and cartilage. The diffusion tensor provides two new types of information of water diffusion: the magnitude and the spatial orientation of water diffusivity inside the tissue. This information has been used for white matter fiber tracking to review physical neuronal pathways inside the brain. Functional MRI measures brain activations using the hemodynamic response. The statistically derived activation map corresponds to human brain functional activities caused by neuronal activities. The combination of these two methods provides a new way to understand human brain from the anatomical neuronal fiber connectivity to functional activities between different brain regions. In this study, virtual reality (VR) based MR DTI and fMRI visualization with high resolution anatomical image segmentation and registration, ROI definition and neuronal white matter fiber tractography visualization and fMRI activation map integration is proposed. Rationale and methods for producing and distributing stereoscopic videos are also discussed.

Widespread cortical morphologic changes in juvenile myoclonic epilepsy: evidence from structural MRI.

LENUS (Irish Health Repository)

Ronan, Lisa

2012-04-01

Atypical morphology of the surface of the cerebral cortex may be related to abnormal cortical folding (gyrification) and therefore may indicate underlying malformations of cortical development (MCDs). Using magnetic resonance imaging (MRI)-based analysis, we examined cortical morphology in patients with juvenile myoclonic epilepsy (JME).

Magnetic Resonance Imaging (MRI) -- Head

Medline Plus

Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

Quantitative Measurements in the Human Hippocampus and Related Areas: Correspondence between Ex-Vivo MRI and Histological Preparations.

Directory of Open Access Journals (Sweden)

José Carlos Delgado-González

Full Text Available The decrease of volume estimates in different structures of the medial temporal lobe related to memory correlate with the decline of cognitive functions in neurodegenerative diseases. This study presents data on the association between MRI quantitative parameters of medial temporal lobe structures and their quantitative estimate in microscopic examination. Twelve control cases had ex-vivo MRI, and thereafter, the temporal lobe of both hemispheres was sectioned from the pole as far as the level of the splenium of the corpus callosum. Nissl stain was used to establish anatomical boundaries between structures in the medial temporal lobe. The study included morphometrical and stereological estimates of the amygdaloid complex, hippocampus, and temporal horn of the lateral ventricle, as well as different regions of grey and white matter in the temporal lobe. Data showed a close association between morphometric MRI images values and those based on the histological determination of boundaries. Only values in perimeter and circularity of the piamater were different. This correspondence is also revealed by the stereological study, although irregular compartments resulted in a lesser agreement. Neither age ( 65 yr nor hemisphere had any effect. Our results indicate that ex-vivo MRI is highly associated with quantitative information gathered by histological examination, and these data could be used as structural MRI biomarker in neurodegenerative diseases.

Initial tests of a prototype MRI-compatible PET imager

Energy Technology Data Exchange (ETDEWEB)

Raylman, Raymond R. [Center for Advanced Imaging, Department of Radiology, West Virginia University, HSB Box 9236, Morgantown, WV (United States)]. E-mail: rraylman@wvu.edu; Majewski, Stan [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Lemieux, Susan [Center for Advanced Imaging, Department of Radiology, West Virginia University, HSB Box 9236, Morgantown, WV (United States); Velan, S. Sendhil [Center for Advanced Imaging, Department of Radiology, West Virginia University, HSB Box 9236, Morgantown, WV (United States); Kross, Brain [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Popov, Vladimir [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Smith, Mark F. [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Weisenberger, Andrew G. [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Wojcik, Randy [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

2006-12-20

Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI, will allow the correlation of form with function. Our group (a collaboration of West Virginia University and Jefferson Lab) is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode with an active FOV of 5x5x4 cm{sup 3}. Each MRI-PET detector module consists of an array of LSO detector elements (2.5x2.5x15 mm{sup 3}) coupled through a long fiber optic light guide to a single Hamamatsu flat panel PSPMT. The fiber optic light guide is made of a glued assembly of 2 mm diameter acrylic fibers with a total length of 2.5 m. The use of a light guides allows the PSPMTs to be positioned outside the bore of the 3 T General Electric MRI scanner used in the tests. Photon attenuation in the light guides resulted in an energy resolution of {approx}60% FWHM, interaction of the magnetic field with PSPMT further reduced energy resolution to {approx}85% FWHM. Despite this effect, excellent multi-plane PET and MRI images of a simple disk phantom were acquired simultaneously. Future work includes improved light guides, optimized magnetic shielding for the PSPMTs, construction of specialized coils to permit high-resolution MRI imaging, and use of the system to perform simultaneous PET and MRI or MR-spectroscopy.

Animal MRI Core

Data.gov (United States)

Federal Laboratory Consortium — The Animal Magnetic Resonance Imaging (MRI) Core develops and optimizes MRI methods for cardiovascular imaging of mice and rats. The Core provides imaging expertise,...

Explaining MRI examinations DVD

International Nuclear Information System (INIS)

Takatsu, Yasuo; Komeda, Takuya

2010-01-01

When conducting MRI examinations, there are various things to be careful of. There is often stress related to the MRI examinations, so in order to perform an examination safely and smoothly, sufficient explanation must be given. An explanation of what to do and what not to do during an examination should be outlined in a brochure given to patients before the examination. There may be many patients who have misgivings about their MRI examinations, so to reduce their anxiousness and deepen their understanding of MRI examinations and to improve the safety and effiency of MRI examinations,; we created a DVD about MRI examinations. We gathered MRI-related safety information and instructions, and assessed the effect that the information might have on patients. We started a workgroup for a project to plan and record a video according to the Storyboard. When editing, we reviewed the length of each segment, the amount of information on screen, and the overall length of the DVD. We discussed the issue within the workgroup and had hospital approval. It was possible for us to complete it without depending on the supplier and the cost was kept to a minimum. Finally, we decided on a viewing location. We asked a hospital volunteers to see a complete DVD and we evaluated their responses by questionnaires. As the result, their understanding and anxieties related to MRI examinations were alleviated, as expected. Their anxiety seemed to be eased. Patients also seemed to have a deeper understanding of MRI examinations having seen an examination being conducted. (author)

MRI of meningioma

International Nuclear Information System (INIS)

Yamamoto, Yoshio; Hiraki, Yoshio; Kaji, Mitumasa

1988-01-01

MRI has gained a prominent position in the diagnosis of brain tumors. We examined 30 cases of meningiomas and distinguished their subtype according to the criteria of Rubinic histology. We discussed the MRI findings and compared then with X-CT findings so to their intensity, delination of tumors, whether accompanied by peripheral edema, and T 1 values. MRI delinated the tumors as well as CE-CT. No remarkable difference was found between the subtypes. (author)

MRI of the cartilage

Energy Technology Data Exchange (ETDEWEB)

Imhof, H.; Noebauer-Huhmann, I.-M.; Krestan, C.; Gahleitner, A.; Marlovits, S.; Trattnig, S. [Department of Osteology, Universitaetklinik fuer Radiodiagnostik, AKH-Vienna, Waehringer Guertel 18-20, 1090 Vienna (Austria); Sulzbacher, I. [Universitaetsklinik fuer Pathologie Vienna, Waehringer Guertel 18-20, 1090 Vienna (Austria)

2002-11-01

With the introduction of fat-suppressed gradient-echo and fast spin-echo (FSE) sequences in clinical routine MR visualization of the hyaline articular cartilage is routinely possible in the larger joints. While 3D gradient-echo with fat suppression allows exact depiction of the thickness and surface of cartilage, FSE outlines the normal and abnormal internal structures of the hyaline cartilage; therefore, both sequences seem to be necessary in a standard MRI protocol for cartilage visualization. In diagnostically ambiguous cases, in which important therapeutic decisions are required, direct MR arthrography is the established imaging standard as an add-on procedure. Despite the social impact and prevalence, until recent years there was a paucity of knowledge about the pathogenesis of cartilage damage. With the introduction of high-resolution MRI with powerful surface coils and fat-suppression techniques, visualization of the articular cartilage is now routinely possible in many joints. After a short summary of the anatomy and physiology of the hyaline cartilage, the different MR imaging methods are discussed and recommended standards are suggested. (orig.)

Abnormal regional homogeneity in Parkinson's disease: a resting state fMRI study

International Nuclear Information System (INIS)

Li, Y.; Liang, P.; Jia, X.; Li, K.

2016-01-01

Aim: To examine the functional brain alterations in Parkinson's disease (PD) by measuring blood oxygenation level dependent (BOLD) functional MRI (fMRI) signals at rest while controlling for the structural atrophy. Materials and methods: Twenty-three PD patients and 20 age, gender, and education level matched normal controls (NC) were included in this study. Resting state fMRI and structural MRI data were acquired. The resting state brain activity was measured by the regional homogeneity (ReHo) method and the grey matter (GM) volume was attained by the voxel-based morphology (VBM) analysis. Two-sample t-test was then performed to detect the group differences with structural atrophy as a covariate. Results: VBM analysis showed GM volume reductions in the left superior frontal gyrus, left paracentral lobule, and left middle frontal gyrus in PD patients as compared to NC. There were widespread ReHo differences between NC and PD patients. Compared to NC, PD patients showed significant alterations in the motor network, including decreased ReHo in the right primary sensory cortex (S1), while increased ReHo in the left premotor area (PMA) and left dorsolateral prefrontal cortex (DLPFC). In addition, a cluster in the left superior occipital gyrus (SOG) also showed increased ReHo in PD patients. Conclusion: The current findings indicate that significant changes of ReHo in the motor and non-motor cortices have been detected in PD patients, independent of age, gender, education level, and structural atrophy. The present study thus suggests ReHo abnormalities as a potential biomarker for the diagnosis of PD and further provides insights into the biological mechanism of the disease. - Highlights: • Functional changes were found in PD patients independent of structural atrophy. • Both increased and decreased ReHo were observed in motor network regions in PD. • Increased ReHo was detected in visual association cortex for PD patients.

Exploring connectivity with large-scale Granger causality on resting-state functional MRI.

Science.gov (United States)

DSouza, Adora M; Abidin, Anas Z; Leistritz, Lutz; Wismüller, Axel

2017-08-01

Large-scale Granger causality (lsGC) is a recently developed, resting-state functional MRI (fMRI) connectivity analysis approach that estimates multivariate voxel-resolution connectivity. Unlike most commonly used multivariate approaches, which establish coarse-resolution connectivity by aggregating voxel time-series avoiding an underdetermined problem, lsGC estimates voxel-resolution, fine-grained connectivity by incorporating an embedded dimension reduction. We investigate application of lsGC on realistic fMRI simulations, modeling smoothing of neuronal activity by the hemodynamic response function and repetition time (TR), and empirical resting-state fMRI data. Subsequently, functional subnetworks are extracted from lsGC connectivity measures for both datasets and validated quantitatively. We also provide guidelines to select lsGC free parameters. Results indicate that lsGC reliably recovers underlying network structure with area under receiver operator characteristic curve (AUC) of 0.93 at TR=1.5s for a 10-min session of fMRI simulations. Furthermore, subnetworks of closely interacting modules are recovered from the aforementioned lsGC networks. Results on empirical resting-state fMRI data demonstrate recovery of visual and motor cortex in close agreement with spatial maps obtained from (i) visuo-motor fMRI stimulation task-sequence (Accuracy=0.76) and (ii) independent component analysis (ICA) of resting-state fMRI (Accuracy=0.86). Compared with conventional Granger causality approach (AUC=0.75), lsGC produces better network recovery on fMRI simulations. Furthermore, it cannot recover functional subnetworks from empirical fMRI data, since quantifying voxel-resolution connectivity is not possible as consequence of encountering an underdetermined problem. Functional network recovery from fMRI data suggests that lsGC gives useful insight into connectivity patterns from resting-state fMRI at a multivariate voxel-resolution. Copyright © 2017 Elsevier B.V. All

Effects of Spaceflight on Astronaut Brain Structure as Indicated on MRI.

Science.gov (United States)

Roberts, Donna R; Albrecht, Moritz H; Collins, Heather R; Asemani, Davud; Chatterjee, A Rano; Spampinato, M Vittoria; Zhu, Xun; Chimowitz, Marc I; Antonucci, Michael U

2017-11-02

There is limited information regarding the effects of spaceflight on the anatomical configuration of the brain and on cerebrospinal fluid (CSF) spaces. We used magnetic resonance imaging (MRI) to compare images of 18 astronauts' brains before and after missions of long duration, involving stays on the International Space Station, and of 16 astronauts' brains before and after missions of short duration, involving participation in the Space Shuttle Program. Images were interpreted by readers who were unaware of the flight duration. We also generated paired preflight and postflight MRI cine clips derived from high-resolution, three-dimensional imaging of 12 astronauts after long-duration flights and from 6 astronauts after short-duration flights in order to assess the extent of narrowing of CSF spaces and the displacement of brain structures. We also compared preflight ventricular volumes with postflight ventricular volumes by means of an automated analysis of T 1 -weighted MRIs. The main prespecified analyses focused on the change in the volume of the central sulcus, the change in the volume of CSF spaces at the vertex, and vertical displacement of the brain. Narrowing of the central sulcus occurred in 17 of 18 astronauts after long-duration flights (mean flight time, 164.8 days) and in 3 of 16 astronauts after short-duration flights (mean flight time, 13.6 days) (P<0.001). Cine clips from a subgroup of astronauts showed an upward shift of the brain after all long-duration flights (12 astronauts) but not after short-duration flights (6 astronauts) and narrowing of CSF spaces at the vertex after all long-duration flights (12 astronauts) and in 1 of 6 astronauts after short-duration flights. Three astronauts in the long-duration group had optic-disk edema, and all 3 had narrowing of the central sulcus. A cine clip was available for 1 of these 3 astronauts, and the cine clip showed upward shift of the brain. Narrowing of the central sulcus, upward shift of the brain

MRI-powered biomedical devices.

Science.gov (United States)

Hovet, Sierra; Ren, Hongliang; Xu, Sheng; Wood, Bradford; Tokuda, Junichi; Tse, Zion Tsz Ho

2017-11-16

Magnetic resonance imaging (MRI) is beneficial for imaging-guided procedures because it provides higher resolution images and better soft tissue contrast than computed tomography (CT), ultrasound, and X-ray. MRI can be used to streamline diagnostics and treatment because it does not require patients to be repositioned between scans of different areas of the body. It is even possible to use MRI to visualize, power, and control medical devices inside the human body to access remote locations and perform minimally invasive procedures. Therefore, MR conditional medical devices have the potential to improve a wide variety of medical procedures; this potential is explored in terms of practical considerations pertaining to clinical applications and the MRI environment. Recent advancements in this field are introduced with a review of clinically relevant research in the areas of interventional tools, endovascular microbots, and closed-loop controlled MRI robots. Challenges related to technology and clinical feasibility are discussed, including MRI based propulsion and control, navigation of medical devices through the human body, clinical adoptability, and regulatory issues. The development of MRI-powered medical devices is an emerging field, but the potential clinical impact of these devices is promising.

Brain morphological and microstructural features in cryptogenic late-onset temporal lobe epilepsy: a structural and diffusion MRI study.

Science.gov (United States)

Sone, Daichi; Sato, Noriko; Kimura, Yukio; Watanabe, Yutaka; Okazaki, Mitsutoshi; Matsuda, Hiroshi

2018-04-13

Although epilepsy in the elderly has attracted attention recently, there are few systematic studies of neuroimaging in such patients. In this study, we used structural MRI and diffusion tensor imaging (DTI) to investigate the morphological and microstructural features of the brain in late-onset temporal lobe epilepsy (TLE). We recruited patients with TLE and an age of onset > 50 years (late-TLE group) and age- and sex-matched healthy volunteers (control group). 3-Tesla MRI scans, including 3D T1-weighted images and 15-direction DTI, showed normal findings on visual assessment in both groups. We used Statistical Parametric Mapping 12 (SPM12) for gray and white matter structural normalization and comparison and used Tract-Based Spatial Statistics (TBSS) for fractional anisotropy and mean diffusivity comparisons of DTI. In both methods, p < 0.05 (family-wise error) was considered statistically significant. In total, 30 patients with late-onset TLE (mean ± SD age, 66.8 ± 8.4; mean ± SD age of onset, 63.0 ± 7.6 years) and 40 healthy controls (mean ± SD age, 66.6 ± 8.5 years) were enrolled. The late-onset TLE group showed significant gray matter volume increases in the bilateral amygdala and anterior hippocampus and significantly reduced mean diffusivity in the left temporofrontal lobe, internal capsule, and brainstem. No significant changes were evident in white matter volume or fractional anisotropy. Our findings may reflect some characteristics or mechanisms of cryptogenic TLE in the elderly, such as inflammatory processes.

MRI findings of juvenile psoriatic arthritis

International Nuclear Information System (INIS)

Lee, Edward Y.; Kleinman, Paul K.; Sundel, Robert P.; Kim, Susan; Zurakowski, David

2008-01-01

The aim of this study was to describe the magnetic resonance imaging (MRI) features of juvenile psoriatic arthritis (JpsA) in children in order to facilitate early diagnosis and proper management. Two pediatric radiologists retrospectively reviewed in consensus a total of 37 abnormal MRI examinations from 31 pediatric patients (nine boys, 22 girls; age range 1-17 years; mean age 9.4 years) who had a definite diagnosis of JpsA and underwent MRI. Each MRI was evaluated for synovium abnormality (thickening and enhancement), joint effusion (small, moderate, and large), bone marrow abnormality (edema, enhancement, and location of abnormality), soft tissue abnormality (edema, enhancement, atrophy, and fatty infiltration), tendon abnormality (thickening, edema, tendon sheath fluid, and enhancement), and articular abnormality (joint space narrowing and erosion). The distribution of abnormal MRI findings among the six categories for the 37 MRI examinations was evaluated. The number of abnormal MRI findings for each MRI examination was assessed. Age at MRI examination and all six categories of abnormal MRI findings according to gender were evaluated. There were a total 96 abnormal MRI findings noted on 37 abnormal MRI examinations from 31 pediatric patients. The 37 abnormal MRI examinations included MRI of the hand (n=8), knee (n = 8), ankle (n = 5), pelvis (n = 5), temporomandibular joint (n = 4), wrist (n = 3), foot (n = 2), elbow (n = 1), and shoulder (n = 1). Twenty-eight diffuse synovial thickening and/or enhancement were the most common MRI abnormality (29.2%). Joint effusion comprised 22 abnormal MRI findings (22.9%). There were 16 abnormal MRI bone marrow edema and/or enhancement findings (16.7%), and in seven (7.3%) the edema involved non-articular sites. Soft tissue abnormality manifested as edema and/or enhancement constituted 14 abnormal MRI findings (14.5%). There were ten MRI abnormalities (10.4%) involving tendons. Articular abnormality seen as joint space

MRI findings of juvenile psoriatic arthritis

Energy Technology Data Exchange (ETDEWEB)

Lee, Edward Y.; Kleinman, Paul K. [Harvard Medical School, Department of Radiology, Boston, MA (United States); Children' s Hospital Boston, MA (United States); Sundel, Robert P.; Kim, Susan [Harvard Medical School, Rheumatology Program, Division of Immunology and the Department of Pediatrics, Boston, MA (United States); Children' s Hospital Boston, MA (United States); Zurakowski, David [Harvard Medical School, Department of Radiology, Boston, MA (United States); Harvard Medical School, Department of Orthopaedic Surgery, Boston, MA (United States); Children' s Hospital Boston, MA (United States)

2008-11-15

The aim of this study was to describe the magnetic resonance imaging (MRI) features of juvenile psoriatic arthritis (JpsA) in children in order to facilitate early diagnosis and proper management. Two pediatric radiologists retrospectively reviewed in consensus a total of 37 abnormal MRI examinations from 31 pediatric patients (nine boys, 22 girls; age range 1-17 years; mean age 9.4 years) who had a definite diagnosis of JpsA and underwent MRI. Each MRI was evaluated for synovium abnormality (thickening and enhancement), joint effusion (small, moderate, and large), bone marrow abnormality (edema, enhancement, and location of abnormality), soft tissue abnormality (edema, enhancement, atrophy, and fatty infiltration), tendon abnormality (thickening, edema, tendon sheath fluid, and enhancement), and articular abnormality (joint space narrowing and erosion). The distribution of abnormal MRI findings among the six categories for the 37 MRI examinations was evaluated. The number of abnormal MRI findings for each MRI examination was assessed. Age at MRI examination and all six categories of abnormal MRI findings according to gender were evaluated. There were a total 96 abnormal MRI findings noted on 37 abnormal MRI examinations from 31 pediatric patients. The 37 abnormal MRI examinations included MRI of the hand (n=8), knee (n = 8), ankle (n = 5), pelvis (n = 5), temporomandibular joint (n = 4), wrist (n = 3), foot (n = 2), elbow (n = 1), and shoulder (n = 1). Twenty-eight diffuse synovial thickening and/or enhancement were the most common MRI abnormality (29.2%). Joint effusion comprised 22 abnormal MRI findings (22.9%). There were 16 abnormal MRI bone marrow edema and/or enhancement findings (16.7%), and in seven (7.3%) the edema involved non-articular sites. Soft tissue abnormality manifested as edema and/or enhancement constituted 14 abnormal MRI findings (14.5%). There were ten MRI abnormalities (10.4%) involving tendons. Articular abnormality seen as joint space

Cine MRI of dissecting aneurysm

International Nuclear Information System (INIS)

Takaki, Hajime

1991-01-01

Cine MRI was performed in 25 cases of aortic dissection and comparative study among cine MRI, spin-echo static MRI, contrast-enhanced CT and intravenous digital subtraction angiography (IVDSA) was made. Cine MRI accurately detected aortic dissection. It was most accurate among various diagnostic methods in demonstration of entry site of dissection. Take-off of renal artery and its relation to true and false channels was also accurately demonstrated by cine MRI. The above results suggest that cine MRI can be an important diagnostic modality with almost equal diagnostic quality to those of conventional angiography. However, further technical improvement to shorten the imaging time seems necessary to replace angiography. (author)

Frequent Benign, Nontraumatic, Noninflammatory Causes of Low Back Pain in Adolescents: MRI Findings

Directory of Open Access Journals (Sweden)

Aikaterini Solomou

2018-01-01

Full Text Available Introduction. Low back pain (LBP is common in children and adolescents. There are many factors that cause LBP, including structural disorders, degenerative changes, Scheuermann’s disease, fractures, inflammation, and tumors. Magnetic Resonance Imaging is the gold standard for diagnosing spinal abnormalities and is mandatory when neurological symptoms exist. The study focuses on common MRI findings in adolescents with persistent LBP, without history of acute trauma or evidence of either inflammatory or rheumatic disease. Materials and Methods. Eleven adolescents were submitted to thoracic and/or lumbar spine MRI due to persistent LBP. The protocol consisted of T1 WI, T2 WI, and T2 WI with FS, in the axial, sagittal, and coronal plane. Results. MRI revealed structural abnormalities (scoliosis and kyphosis in 4/11 (36.36%; disc abnormalities and endplate changes were found on 11/11 (100%. Typical Scheuermann’s disease was found in 3/11 (27.27%. Endplate changes were severe in Scheuermann’s patients and mild to moderate in the remaining 8/11 (72.72%. Kyphosis was in all cases secondary to Scheuermann’s disease. Disk bulges and hernias were found in 8/11 (72.72%, all located in the lumbar spine. Conclusion. In adolescents with LBP, structural spinal disorders, degenerative changes, and Scheuermann’s disease are commonly found on MRI; however, degenerative changes prevail.

MRI in head trauma

International Nuclear Information System (INIS)

Hong, Jin Kyo

1986-01-01

In the diagnosis of head injury, Magnetic Resonance Imaging (MRI), like CT, is an effective method of distinguishing between intracerebral and extracerebral lesions. In our experience of MRI, early hematomas are almost isointense by Saturation Recovery (SR) method, so these must be performed with Spin Echo (SE) method for better visualization of hematomas. Isodense subdural hematomas, which is a diagnostic dilemma on CT images, are clearly seen on MRI. Delayed hematomas or residual parenchymal lesions are better demonstrated on MRI than on CT. Direct cornal, sagittal images and multiplanar facility of MRI provides excellent visualization of the the location and shape of extracerebral collection of hematoma. For the screening of head traumas, SE method is a technique of choice because of its excellent sensitivity within limited time.

MRI in head trauma

Energy Technology Data Exchange (ETDEWEB)

Hong, Jin Kyo [Shin Wha Hospital, Seoul (Korea, Republic of)

1986-02-15

In the diagnosis of head injury, Magnetic Resonance Imaging (MRI), like CT, is an effective method of distinguishing between intracerebral and extracerebral lesions. In our experience of MRI, early hematomas are almost isointense by Saturation Recovery (SR) method, so these must be performed with Spin Echo (SE) method for better visualization of hematomas. Isodense subdural hematomas, which is a diagnostic dilemma on CT images, are clearly seen on MRI. Delayed hematomas or residual parenchymal lesions are better demonstrated on MRI than on CT. Direct cornal, sagittal images and multiplanar facility of MRI provides excellent visualization of the the location and shape of extracerebral collection of hematoma. For the screening of head traumas, SE method is a technique of choice because of its excellent sensitivity within limited time.

MRI parcellation of ex vivo medial temporal lobe.

Science.gov (United States)

Augustinack, Jean C; Magnain, Caroline; Reuter, Martin; van der Kouwe, André J W; Boas, David; Fischl, Bruce

2014-06-01

Recent advancements in radio frequency coils, field strength and sophisticated pulse sequences have propelled modern brain mapping and have made validation to biological standards - histology and pathology - possible. The medial temporal lobe has long been established as a pivotal brain region for connectivity, function and unique structure in the human brain, and reveals disconnection in mild Alzheimer's disease. Specific brain mapping of mesocortical areas affected with neurofibrillary tangle pathology early in disease progression provides not only an accurate description for location of these areas but also supplies spherical coordinates that allow comparison between other ex vivo cases and larger in vivo datasets. We have identified several cytoarchitectonic features in the medial temporal lobe with high resolution ex vivo MRI, including gray matter structures such as the entorhinal layer II 'islands', perirhinal layer II-III columns, presubicular 'clouds', granule cell layer of the dentate gyrus as well as lamina of the hippocampus. Localization of Brodmann areas 28 and 35 (entorhinal and perirhinal, respectively) demonstrates MRI based area boundaries validated with multiple methods and histological stains. Based on our findings, both myelin and Nissl staining relate to contrast in ex vivo MRI. Precise brain mapping serves to create modern atlases for cortical areas, allowing accurate localization with important applications to detecting early disease processes. Copyright © 2013 Elsevier Inc. All rights reserved.

Development of an MRI-compatible digital SiPM detector stack for simultaneous PET/MRI.

Science.gov (United States)

Düppenbecker, Peter M; Weissler, Bjoern; Gebhardt, Pierre; Schug, David; Wehner, Jakob; Marsden, Paul K; Schulz, Volkmar

2016-02-01

Advances in solid-state photon detectors paved the way to combine positron emission tomography (PET) and magnetic resonance imaging (MRI) into highly integrated, truly simultaneous, hybrid imaging systems. Based on the most recent digital SiPM technology, we developed an MRI-compatible PET detector stack, intended as a building block for next generation simultaneous PET/MRI systems. Our detector stack comprises an array of 8 × 8 digital SiPM channels with 4 mm pitch using Philips Digital Photon Counting DPC 3200-22 devices, an FPGA for data acquisition, a supply voltage control system and a cooling infrastructure. This is the first detector design that allows the operation of digital SiPMs simultaneously inside an MRI system. We tested and optimized the MRI-compatibility of our detector stack on a laboratory test bench as well as in combination with a Philips Achieva 3 T MRI system. Our design clearly reduces distortions of the static magnetic field compared to a conventional design. The MRI static magnetic field causes weak and directional drift effects on voltage regulators, but has no direct impact on detector performance. MRI gradient switching initially degraded energy and timing resolution. Both distortions could be ascribed to voltage variations induced on the bias and the FPGA core voltage supply respectively. Based on these findings, we improved our detector design and our final design shows virtually no energy or timing degradations, even during heavy and continuous MRI gradient switching. In particular, we found no evidence that the performance of the DPC 3200-22 digital SiPM itself is degraded by the MRI system.

In vivo longitudinal MRI and behavioral studies in experimental spinal cord injury.

Science.gov (United States)

Sundberg, Laura M; Herrera, Juan J; Narayana, Ponnada A

2010-10-01

Comprehensive in vivo longitudinal studies that include multi-modal magnetic resonance imaging (MRI) and a battery of behavioral assays to assess functional outcome were performed at multiple time points up to 56 days post-traumatic spinal cord injury (SCI) in rodents. The MRI studies included high-resolution structural imaging for lesion volumetry, and diffusion tensor imaging (DTI) for probing the white matter integrity. The behavioral assays included open-field locomotion, grid walking, inclined plane, computerized activity box performance, and von Frey filament tests. Additionally, end-point histology was assessed for correlation with both the MRI and behavioral data. The temporal patterns of the lesions were documented on structural MRI. DTI studies showed significant changes in white matter that is proximal to the injury epicenter and persisted to day 56. White matter in regions up to 1 cm away from the injury epicenter that appeared normal on conventional MRI also exhibited changes that were indicative of tissue damage, suggesting that DTI is a more sensitive measure of the evolving injury. Correlations between DTI and histology after SCI could not be firmly established, suggesting that injury causes complex pathological changes in multiple tissue components that affect the DTI measures. Histological evidence confirmed a significant decrease in myelin and oligodendrocyte presence 56 days post-SCI. Multiple assays to evaluate aspects of functional recovery correlated with histology and DTI measures, suggesting that damage to specific white matter tracts can be assessed and tracked longitudinally after SCI.

Ovarian cysts on prenatal MRI

International Nuclear Information System (INIS)

Nemec, Ursula; Nemec, Stefan F.; Bettelheim, Dieter; Brugger, Peter C.; Horcher, Ernst; Schöpf, Veronika; Graham, John M.; Rimoin, David L.; Weber, Michael; Prayer, Daniela

2012-01-01

Objective: Ovarian cysts are the most frequently encountered intra-abdominal masses in females in utero. They may, at times, require perinatal intervention. Using magnetic resonance imaging (MRI) as an adjunct to ultrasonography (US) in prenatal diagnosis, we sought to demonstrate the ability to visualize ovarian cysts on prenatal MRI. Materials and methods: This retrospective study included 17 fetal MRI scans from 16 female fetuses (23–37 gestational weeks) with an MRI diagnosis of ovarian cysts after suspicious US findings. A multiplanar MRI protocol was applied to image and to characterize the cysts. The US and MRI findings were compared, and the prenatal findings were compared with postnatal imaging findings or histopathology. Results: Simple ovarian cysts were found in 10/16 cases and complex cysts in 7/16 cases, including one case with both. In 11/16 (69%) cases, US and MRI diagnoses were in agreement, and, in 5/16 (31%) cases, MRI specified or expanded the US diagnosis. In 6/16 cases, postnatal US showed that the cysts spontaneously resolved or decreased in size, and in 1/16 cases, postnatal imaging confirmed a hemorrhagic cyst. In 4/16 cases, the prenatal diagnoses were confirmed by surgery/histopathology, and for the rest, postnatal correlation was not available. Conclusion: Our results illustrate the MRI visualization of ovarian cysts in utero. In most cases, MRI will confirm the US diagnosis. In certain cases, MRI may provide further diagnostic information, additional to US, which is the standard technique for diagnosis, monitoring, and treatment planning.

Ovarian cysts on prenatal MRI

Energy Technology Data Exchange (ETDEWEB)

Nemec, Ursula [Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Nemec, Stefan F., E-mail: stefan.nemec@meduniwien.ac.at [Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Medical Genetics Institute, Cedars Sinai Medical Center, 8700 Beverly Boulevard, PACT Suite 400, Los Angeles, CA 90048 (United States); Bettelheim, Dieter [Department of Obstetrics and Gynaecology, Division of Prenatal Diagnosis and Therapy, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Brugger, Peter C. [Center of Anatomy and Cell Biology, Integrative Morphology Group, Medical University Vienna, Waehringerstrasse 13, A-1090 Vienna (Austria); Horcher, Ernst [Department of Pediatric Surgery, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Schoepf, Veronika [Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Graham, John M.; Rimoin, David L. [Medical Genetics Institute, Cedars Sinai Medical Center, 8700 Beverly Boulevard, PACT Suite 400, Los Angeles, CA 90048 (United States); Weber, Michael; Prayer, Daniela [Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria)

2012-08-15

Objective: Ovarian cysts are the most frequently encountered intra-abdominal masses in females in utero. They may, at times, require perinatal intervention. Using magnetic resonance imaging (MRI) as an adjunct to ultrasonography (US) in prenatal diagnosis, we sought to demonstrate the ability to visualize ovarian cysts on prenatal MRI. Materials and methods: This retrospective study included 17 fetal MRI scans from 16 female fetuses (23-37 gestational weeks) with an MRI diagnosis of ovarian cysts after suspicious US findings. A multiplanar MRI protocol was applied to image and to characterize the cysts. The US and MRI findings were compared, and the prenatal findings were compared with postnatal imaging findings or histopathology. Results: Simple ovarian cysts were found in 10/16 cases and complex cysts in 7/16 cases, including one case with both. In 11/16 (69%) cases, US and MRI diagnoses were in agreement, and, in 5/16 (31%) cases, MRI specified or expanded the US diagnosis. In 6/16 cases, postnatal US showed that the cysts spontaneously resolved or decreased in size, and in 1/16 cases, postnatal imaging confirmed a hemorrhagic cyst. In 4/16 cases, the prenatal diagnoses were confirmed by surgery/histopathology, and for the rest, postnatal correlation was not available. Conclusion: Our results illustrate the MRI visualization of ovarian cysts in utero. In most cases, MRI will confirm the US diagnosis. In certain cases, MRI may provide further diagnostic information, additional to US, which is the standard technique for diagnosis, monitoring, and treatment planning.

Wilson's disease: cranial MRI observations and clinical correlation

Energy Technology Data Exchange (ETDEWEB)

Sinha, S.; Taly, A.B.; Prashanth, L.K.; Venugopal, K.S.; Arunodaya, G.R.; Swamy, H.S. [National Institute of Mental Health and Neurosciences (NIMHANS), Department of Neurology, Bangalore (India); Ravishankar, S.; Vasudev, M.K. [National Institute of Mental Health and Neurosciences (NIMHANS), Department of Neuroimaging and Interventional Radiology, Bangalore (India)

2006-09-15

Study of MRI changes may be useful in diagnosis, prognosis and better understanding of the pathophysiology of Wilson's disease (WD). We aimed to describe and correlate the MRI abnormalities of the brain with clinical features in WD. MRI evaluation was carried out in 100 patients (57 males, 43 females; mean age 19.3{+-}8.9 years) using standard protocols. All but 18 patients were on de-coppering agents. Their history, clinical manifestations and scores for severity of disease were noted. The mean duration of illness and treatment were 8.3{+-}10.8 years and 7.5{+-}7.1 years respectively. MRI of the brain was abnormal in all the 93 symptomatic patients. The most conspicuous observations were atrophy of the cerebrum (70%), brainstem (66%) and cerebellum (52%). Signal abnormalities were also noted: putamen (72%), caudate (61%), thalami (58%), midbrain (49%), pons (20%), cerebral white matter (25%), cortex (9%), medulla (12%) and cerebellum (10%). The characteristic T2-W globus pallidal hypointensity (34%), ''Face of giant panda'' sign (12%), T1-W striatal hyperintensity (6%), central pontine myelinosis (7%), and bright claustral sign (4%) were also detected. MRI changes correlated with disease severity scores (P<0.001) but did not correlate with the duration of illness. MRI changes were universal but diverse and involved almost all the structures of the brain in symptomatic patients. A fair correlation between MRI observations and various clinical features provides an explanation for the protean manifestations of the disease. (orig.)

Automated processing pipeline for neonatal diffusion MRI in the developing Human Connectome Project.

Science.gov (United States)

Bastiani, Matteo; Andersson, Jesper L R; Cordero-Grande, Lucilio; Murgasova, Maria; Hutter, Jana; Price, Anthony N; Makropoulos, Antonios; Fitzgibbon, Sean P; Hughes, Emer; Rueckert, Daniel; Victor, Suresh; Rutherford, Mary; Edwards, A David; Smith, Stephen M; Tournier, Jacques-Donald; Hajnal, Joseph V; Jbabdi, Saad; Sotiropoulos, Stamatios N

2018-05-28

The developing Human Connectome Project is set to create and make available to the scientific community a 4-dimensional map of functional and structural cerebral connectivity from 20 to 44 weeks post-menstrual age, to allow exploration of the genetic and environmental influences on brain development, and the relation between connectivity and neurocognitive function. A large set of multi-modal MRI data from fetuses and newborn infants is currently being acquired, along with genetic, clinical and developmental information. In this overview, we describe the neonatal diffusion MRI (dMRI) image processing pipeline and the structural connectivity aspect of the project. Neonatal dMRI data poses specific challenges, and standard analysis techniques used for adult data are not directly applicable. We have developed a processing pipeline that deals directly with neonatal-specific issues, such as severe motion and motion-related artefacts, small brain sizes, high brain water content and reduced anisotropy. This pipeline allows automated analysis of in-vivo dMRI data, probes tissue microstructure, reconstructs a number of major white matter tracts, and includes an automated quality control framework that identifies processing issues or inconsistencies. We here describe the pipeline and present an exemplar analysis of data from 140 infants imaged at 38-44 weeks post-menstrual age. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Development and Assessment of a New 3D Neuroanatomy Teaching Tool for MRI Training

Science.gov (United States)

Drapkin, Zachary A.; Lindgren, Kristen A.; Lopez, Michael J.; Stabio, Maureen E.

2015-01-01

A computerized three-dimensional (3D) neuroanatomy teaching tool was developed for training medical students to identify subcortical structures on a magnetic resonance imaging (MRI) series of the human brain. This program allows the user to transition rapidly between two-dimensional (2D) MRI slices, 3D object composites, and a combined model in…

Competitive advantage of PET/MRI

Energy Technology Data Exchange (ETDEWEB)

Jadvar, Hossein, E-mail: jadvar@usc.edu; Colletti, Patrick M.

2014-01-15

Multimodality imaging has made great strides in the imaging evaluation of patients with a variety of diseases. Positron emission tomography/computed tomography (PET/CT) is now established as the imaging modality of choice in many clinical conditions, particularly in oncology. While the initial development of combined PET/magnetic resonance imaging (PET/MRI) was in the preclinical arena, hybrid PET/MR scanners are now available for clinical use. PET/MRI combines the unique features of MRI including excellent soft tissue contrast, diffusion-weighted imaging, dynamic contrast-enhanced imaging, fMRI and other specialized sequences as well as MR spectroscopy with the quantitative physiologic information that is provided by PET. Most evidence for the potential clinical utility of PET/MRI is based on studies performed with side-by-side comparison or software-fused MRI and PET images. Data on distinctive utility of hybrid PET/MRI are rapidly emerging. There are potential competitive advantages of PET/MRI over PET/CT. In general, PET/MRI may be preferred over PET/CT where the unique features of MRI provide more robust imaging evaluation in certain clinical settings. The exact role and potential utility of simultaneous data acquisition in specific research and clinical settings will need to be defined. It may be that simultaneous PET/MRI will be best suited for clinical situations that are disease-specific, organ-specific, related to diseases of the children or in those patients undergoing repeated imaging for whom cumulative radiation dose must be kept as low as reasonably achievable. PET/MRI also offers interesting opportunities for use of dual modality probes. Upon clear definition of clinical utility, other important and practical issues related to business operational model, clinical workflow and reimbursement will also be resolved.

Competitive advantage of PET/MRI.

Science.gov (United States)

Jadvar, Hossein; Colletti, Patrick M

2014-01-01

Multimodality imaging has made great strides in the imaging evaluation of patients with a variety of diseases. Positron emission tomography/computed tomography (PET/CT) is now established as the imaging modality of choice in many clinical conditions, particularly in oncology. While the initial development of combined PET/magnetic resonance imaging (PET/MRI) was in the preclinical arena, hybrid PET/MR scanners are now available for clinical use. PET/MRI combines the unique features of MRI including excellent soft tissue contrast, diffusion-weighted imaging, dynamic contrast-enhanced imaging, fMRI and other specialized sequences as well as MR spectroscopy with the quantitative physiologic information that is provided by PET. Most evidence for the potential clinical utility of PET/MRI is based on studies performed with side-by-side comparison or software-fused MRI and PET images. Data on distinctive utility of hybrid PET/MRI are rapidly emerging. There are potential competitive advantages of PET/MRI over PET/CT. In general, PET/MRI may be preferred over PET/CT where the unique features of MRI provide more robust imaging evaluation in certain clinical settings. The exact role and potential utility of simultaneous data acquisition in specific research and clinical settings will need to be defined. It may be that simultaneous PET/MRI will be best suited for clinical situations that are disease-specific, organ-specific, related to diseases of the children or in those patients undergoing repeated imaging for whom cumulative radiation dose must be kept as low as reasonably achievable. PET/MRI also offers interesting opportunities for use of dual modality probes. Upon clear definition of clinical utility, other important and practical issues related to business operational model, clinical workflow and reimbursement will also be resolved. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Competitive advantage of PET/MRI

International Nuclear Information System (INIS)

Jadvar, Hossein; Colletti, Patrick M.

2014-01-01

Multimodality imaging has made great strides in the imaging evaluation of patients with a variety of diseases. Positron emission tomography/computed tomography (PET/CT) is now established as the imaging modality of choice in many clinical conditions, particularly in oncology. While the initial development of combined PET/magnetic resonance imaging (PET/MRI) was in the preclinical arena, hybrid PET/MR scanners are now available for clinical use. PET/MRI combines the unique features of MRI including excellent soft tissue contrast, diffusion-weighted imaging, dynamic contrast-enhanced imaging, fMRI and other specialized sequences as well as MR spectroscopy with the quantitative physiologic information that is provided by PET. Most evidence for the potential clinical utility of PET/MRI is based on studies performed with side-by-side comparison or software-fused MRI and PET images. Data on distinctive utility of hybrid PET/MRI are rapidly emerging. There are potential competitive advantages of PET/MRI over PET/CT. In general, PET/MRI may be preferred over PET/CT where the unique features of MRI provide more robust imaging evaluation in certain clinical settings. The exact role and potential utility of simultaneous data acquisition in specific research and clinical settings will need to be defined. It may be that simultaneous PET/MRI will be best suited for clinical situations that are disease-specific, organ-specific, related to diseases of the children or in those patients undergoing repeated imaging for whom cumulative radiation dose must be kept as low as reasonably achievable. PET/MRI also offers interesting opportunities for use of dual modality probes. Upon clear definition of clinical utility, other important and practical issues related to business operational model, clinical workflow and reimbursement will also be resolved

MRI detection of posterior urethral diverticulum following surgical repair of anorectal malformations

Directory of Open Access Journals (Sweden)

Ishan Kumar

2017-09-01

Full Text Available Aim: To identify and to assess imaging and clinical features of Posterior urethral diverticula (PUD in a single-centre series and include a brief review of literature. Materials and method: Post operative MRI of 140 children from north India were retrospectively reviewed who underwent surgical repair for anorectal malformation (ARM along with the Hospital records. Results: Ten cases had MRI features of posterior urethral diverticulum. All of these patients had undergone primary abdominoperineal pull through (APPT procedure. The lesions ranged between 6 mm and 38 mm in size. Two of these lesions were missed in the post operative MRI report. Only one of these patients was symptomatic and presented with dribbling of urine and gross bilateral vesicoureteric reflux in which the diverticulum was excised surgically. Conclusion: PUD is an under-recognised entity and can be identified in preclinical stage on MRI. Careful assessment of urethra and periurethral structures should be a mandatory step in MRI evaluation of post repair ARM cases. An observational conservative approach in selected asymptomatic patients can be an effective management strategy. Keywords: Posterior urethral diverticulum, MRI, Anorectal malformation

Stereotactic imaging for radiotherapy: accuracy of CT, MRI, PET and SPECT

International Nuclear Information System (INIS)

Karger, Christian P; Hipp, Peter; Henze, Marcus; Echner, Gernot; Hoess, Angelika; Schad, Lothar; Hartmann, Guenther H

2003-01-01

CT, MRI, PET and SPECT provide complementary information for treatment planning in stereotactic radiotherapy. Stereotactic correlation of these images requires commissioning tests to confirm the localization accuracy of each modality. A phantom was developed to measure the accuracy of stereotactic localization for CT, MRI, PET and SPECT in the head and neck region. To this end, the stereotactically measured coordinates of structures within the phantom were compared with their mechanically defined coordinates. For MRI, PET and SPECT, measurements were performed using two different devices. For MRI, T1- and T2-weighted imaging sequences were applied. For each measurement, the mean radial deviation in space between the stereotactically measured and mechanically defined position of target points was determined. For CT, the mean radial deviation was 0.4 ± 0.2 mm. For MRI, the mean deviations ranged between 0.7 ± 0.2 mm and 1.4 ± 0.5 mm, depending on the MRI device and the imaging sequence. For PET, mean deviations of 1.1 ± 0.5 mm and 2.4 ± 0.3 mm were obtained. The mean deviations for SPECT were 1.6 ± 0.5 mm and 2.0 ± 0.6 mm. The phantom is well suited to determine the accuracy of stereotactic localization with CT, MRI, PET and SPECT in the head and neck region. The obtained accuracy is well below the physical resolution for CT, PET and SPECT, and of comparable magnitude for MRI. Since the localization accuracy may be device dependent, results obtained at one device cannot be generalized to others

Real-time motion analytics during brain MRI improve data quality and reduce costs.

Science.gov (United States)

Dosenbach, Nico U F; Koller, Jonathan M; Earl, Eric A; Miranda-Dominguez, Oscar; Klein, Rachel L; Van, Andrew N; Snyder, Abraham Z; Nagel, Bonnie J; Nigg, Joel T; Nguyen, Annie L; Wesevich, Victoria; Greene, Deanna J; Fair, Damien A

2017-11-01

Head motion systematically distorts clinical and research MRI data. Motion artifacts have biased findings from many structural and functional brain MRI studies. An effective way to remove motion artifacts is to exclude MRI data frames affected by head motion. However, such post-hoc frame censoring can lead to data loss rates of 50% or more in our pediatric patient cohorts. Hence, many scanner operators collect additional 'buffer data', an expensive practice that, by itself, does not guarantee sufficient high-quality MRI data for a given participant. Therefore, we developed an easy-to-setup, easy-to-use Framewise Integrated Real-time MRI Monitoring (FIRMM) software suite that provides scanner operators with head motion analytics in real-time, allowing them to scan each subject until the desired amount of low-movement data has been collected. Our analyses show that using FIRMM to identify the ideal scan time for each person can reduce total brain MRI scan times and associated costs by 50% or more. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

The capabilities of simultaneous use of SPECT and MRI findings at removal of brain tumors using neuronavigation

International Nuclear Information System (INIS)

Makejev, S.S.; Rozumenko, V.D.; Rozumenko, A.V.; Chuvashova, O.Yu.

2010-01-01

The purpose of the work was to determine the capabilities of SPECT and MRI at intra-operative determining of interrelation of the tumor and FIA. MRI revealed the peculiarities of the tumor structure, SPECT - highly proliferating tumors.

MRI and ultrasound in children with juvenile chronic arthritis

International Nuclear Information System (INIS)

Lamer, S.; Sebag, G.H.

2000-01-01

In this era of advancing imaging technology, a knowledge of the relative values of available imaging techniques is necessary to optimize the management of children with juvenile chronic arthritis (JCA). After clinical examination, plain films remain the initial investigation. The need for radiation protection must be a priority in children with JCA. Conventional radiographs allow grouping of the various arthritides (on the base of the distribution and pattern of joint space changes) and staging of disease progression. Ultrasound (US) is very sensitive in the detection of joint effusions, especially in the hip, and guides fluid aspiration. US and Doppler can be used for the evaluation of synovial hypertrophy and activity. Arthrography and to a certain extent nuclear studies have been replaced by magnetic resonance imaging (MRI). MRI can demonstrate articular cartilage, joint effusion, synovial hypertrophy, cortical and medullary bone, cartilage and bone perfusion, and fibrocartilaginous structures (menisci and ligaments). Contrast enhanced MRI is the most sensitive modality to determine whether an arthritic condition is present. However, it does not assist in establishing a specific diagnosis. MRI determines accurately the activity and the extent of the disease and is particularly useful in the early detection of articular damage. Finally, MRI is of major importance in the evaluation of response to local therapy (especially steroids) and the detection of complications

Fetal central nervous system anomalies: fast MRI vs ultrasonography

International Nuclear Information System (INIS)

Yang Wenzhong; Xia Liming; Yang Minjie; Feng Dingyi; Hu Junwu; Zou Mingli; Wang Chengyuan; Chen Xinlin; Yang Xiaohong

2006-01-01

Objective: To evaluate the ability of fast MRI to detect fetal central nervous system (CNS) anomalies and to compare its performance with that of prenatal ultrasonography (US). Methods Forty-eight pregnant women were detected by conventional prenatal US and MRI. Twenty-two fetuses with CNS anomalies were conformed by autopsy and follow-up. The MR and US appearances of fetal CNS structure were compared to each other and to that of autopsy. Results: A total of 26 CNS anomalies were identified by autopsy (n=17) and follow-up (n=9) including anencephaly (n=6), rachischisis (n=2), encephalocele (n=3), congenital hydrocephalus (n=7), alobar holoprosencephaly (n=1), porencephalia (n=3), arachnoid cyst (n=2) and choroids plexus cyst (n=2). US diagnosed 24 CNS anomalies, the correct diagnostic rate was 92.3%, the false-positive rate was 3.8%, the missed-diagnostic rate was 3.8%. MRI diagnosed 23 CNS anomalies, the correct-diagnostic rate was 88.5%, the false-positive rate was 3.8% ,the missed-diagnostic rate was 7.7%. There was no difference between US and MRI (P>0.05), but MRI have larger FOV, higher tissues resolution, and can demonstrate gray-white matter in detail. Conclusions: MR imaging has a similar sensitivity to that of US in the detection of fetal CNS anomalies. (authors)

Imaging technique and current status of valvular heart disease using cardiac MRI

International Nuclear Information System (INIS)

Lotz, J.; Sohns, J.M.

2013-01-01

The main indications for cardiac magnetic resonance imaging (MRI) in the evaluation of valvular heart disease are pathologies of the aortic and pulmonary valve. For mitral and tricuspid valve pathologies MRI is not the first line modality as these are usually well visualized by echocardiography. The advantages of MRI in valvular heart disease are a high reliability in the evaluation of ventricular volumes and function as well as the assessment of the perivalvular arterial or atrial structures. This reliability and the limitless access to any imaging plane partially compensates for the lower temporal and spatial resolution in comparison to echocardiography. In patients with congenital heart disease, cardiac MRI is established as a valuable diagnostic tool in daily clinical management, especially for the evaluation of pulmonary valve defects. Nevertheless, echocardiography remains the first-line diagnostic imaging tool for the foreseeable future. (orig.) [de

Development and validation of an MRI reference criterion for defining a positive SIJ MRI in spondyloarthritis

DEFF Research Database (Denmark)

Weber, Ulrich; Zubler, Veronika; Pedersen, Susanne J

2012-01-01

OBJECTIVE: To validate an MRI reference criterion for a positive SIJ MRI based on the level of confidence in classification of spondyloarthritis (SpA) by expert MRI readers. METHODS: Four readers assessed SIJ MRI in two inception cohorts (A/B) of 157 consecutive back pain patients ≤50 years, and ...... using two inception cohorts and comparing clinical and MRI-based classification supports the case for including both erosion and BME to define a positive SIJ MRI for the classification of axial SpA. © 2012 by the American College of Rheumatology.......OBJECTIVE: To validate an MRI reference criterion for a positive SIJ MRI based on the level of confidence in classification of spondyloarthritis (SpA) by expert MRI readers. METHODS: Four readers assessed SIJ MRI in two inception cohorts (A/B) of 157 consecutive back pain patients ≤50 years......, and in 20 healthy controls. Patients were classified according to clinical examination and pelvic radiography as having non-radiographic axial SpA (n=51), ankylosing spondylitis (n=34), or non-specific back pain (n=72). Readers recorded their level of confidence in the classification of SpA on a 0-10 scale...

Integrating histology and MRI in the first digital brain of common squirrel monkey, Saimiri sciureus

Science.gov (United States)

Sun, Peizhen; Parvathaneni, Prasanna; Schilling, Kurt G.; Gao, Yurui; Janve, Vaibhav; Anderson, Adam; Landman, Bennett A.

2015-03-01

This effort is a continuation of development of a digital brain atlas of the common squirrel monkey, Saimiri sciureus, a New World monkey with functional and microstructural organization of central nervous system similar to that of humans. Here, we present the integration of histology with multi-modal magnetic resonance imaging (MRI) atlas constructed from the brain of an adult female squirrel monkey. The central concept of this work is to use block face photography to establish an intermediate common space in coordinate system which preserves the high resolution in-plane resolution of histology while enabling 3-D correspondence with MRI. In vivo MRI acquisitions include high resolution T2 structural imaging (300 μm isotropic) and low resolution diffusion tensor imaging (600 um isotropic). Ex vivo MRI acquisitions include high resolution T2 structural imaging and high resolution diffusion tensor imaging (both 300 μm isotropic). Cortical regions were manually annotated on the co-registered volumes based on published histological sections in-plane. We describe mapping of histology and MRI based data of the common squirrel monkey and construction of a viewing tool that enable online viewing of these datasets. The previously descried atlas MRI is used for its deformation to provide accurate conformation to the MRI, thus adding information at the histological level to the MRI volume. This paper presents the mapping of single 2D image slice in block face as a proof of concept and this can be extended to map the atlas space in 3D coordinate system as part of the future work and can be loaded to an XNAT system for further use.

Standard high-resolution pelvic MRI vs. low-resolution pelvic MRI in the evaluation of deep infiltrating endometriosis

International Nuclear Information System (INIS)

Scardapane, Arnaldo; Lorusso, Filomenamila; Ferrante, Annunziata; Stabile Ianora, Amato Antonio; Angelelli, Giuseppe; Scioscia, Marco

2014-01-01

To compare the capabilities of standard pelvic MRI with low-resolution pelvic MRI using fast breath-hold sequences to evaluate deep infiltrating endometriosis (DIE). Sixty-eight consecutive women with suspected DIE were studied with pelvic MRI. A double-acquisition protocol was carried out in each case. High-resolution (HR)-MRI consisted of axial, sagittal, and coronal TSE T2W images, axial TSE T1W, and axial THRIVE. Low-resolution (LR)-MRI was acquired using fast single shot (SSH) T2 and T1 images. Two radiologists with 10 and 2 years of experience reviewed HR and LR images in two separate sessions. The presence of endometriotic lesions of the uterosacral ligament (USL), rectovaginal septum (RVS), pouch of Douglas (POD), and rectal wall was noted. The accuracies of LR-MRI and HR-MRI were compared with the laparoscopic and histopathological findings. Average acquisition times were 24 minutes for HR-MRI and 7 minutes for LR-MRI. The more experienced radiologist achieved higher accuracy with both HR-MRI and LR-MRI. The values of sensitivity, specificity, PPV, NPV, and accuracy did not significantly change between HR and LR images or interobserver agreement for all of the considered anatomic sites. LR-MRI performs as well as HR-MRI and is a valuable tool for the detection of deep endometriosis extension. (orig.)

Standard high-resolution pelvic MRI vs. low-resolution pelvic MRI in the evaluation of deep infiltrating endometriosis

Energy Technology Data Exchange (ETDEWEB)

Scardapane, Arnaldo; Lorusso, Filomenamila; Ferrante, Annunziata; Stabile Ianora, Amato Antonio; Angelelli, Giuseppe [University Hospital ' ' Policlinico' ' of Bari, Interdisciplinary Department of Medicine, Bari (Italy); Scioscia, Marco [Sacro Cuore Don Calabria General Hospital, Department of Obstetrics and Gynecology, Negrar, Verona (Italy)

2014-10-15

To compare the capabilities of standard pelvic MRI with low-resolution pelvic MRI using fast breath-hold sequences to evaluate deep infiltrating endometriosis (DIE). Sixty-eight consecutive women with suspected DIE were studied with pelvic MRI. A double-acquisition protocol was carried out in each case. High-resolution (HR)-MRI consisted of axial, sagittal, and coronal TSE T2W images, axial TSE T1W, and axial THRIVE. Low-resolution (LR)-MRI was acquired using fast single shot (SSH) T2 and T1 images. Two radiologists with 10 and 2 years of experience reviewed HR and LR images in two separate sessions. The presence of endometriotic lesions of the uterosacral ligament (USL), rectovaginal septum (RVS), pouch of Douglas (POD), and rectal wall was noted. The accuracies of LR-MRI and HR-MRI were compared with the laparoscopic and histopathological findings. Average acquisition times were 24 minutes for HR-MRI and 7 minutes for LR-MRI. The more experienced radiologist achieved higher accuracy with both HR-MRI and LR-MRI. The values of sensitivity, specificity, PPV, NPV, and accuracy did not significantly change between HR and LR images or interobserver agreement for all of the considered anatomic sites. LR-MRI performs as well as HR-MRI and is a valuable tool for the detection of deep endometriosis extension. (orig.)

MRI of 'brain death'

International Nuclear Information System (INIS)

Nishino, Shigeki; Itoh, Takahiko; Tuchida, Shohei; Kinugasa, Kazushi; Asari, Shoji; Nishimoto, Akira; Sanou, Kazuo.

1990-01-01

Magnetic resonance imaging (MRI) was undertaken for two patients who suffered from severe cerebrovascular diseases and were clinically brain dead. The MRI system we used was Resona (Yokogawa Medical Systems, superconductive system 0.5 T) and the CT apparatus was Toshiba TCT-300. Initial CT and MRI were undertaken as soon as possible after admission, and repeated sequentially. After diagnosis of brain death, we performed angiography to determine cerebral circulatory arrest, and MRI obtained at the same time was compared with the angiogram and CT. Case 1 was a 77-year-old man who was admitted in an unconscious state. CT and MRI on the second day after hospitalization revealed cerebellar infarction. He was diagnosed as brain dead on day 4. Case 2 was a 35-year-old man. When he was transferred to our hospital, he was in cardiorespiratory arrested. Cardiac resuscitation was successful but no spontaneous respiration appeared. CT and MRI on admission revealed right intracerebral hemorrhage. Angiography revealed cessation of contrast medium in intracranial vessels in both of the patients. We found no 'flow signal void sign' in the bilateral internal carotid and basilar arteries on MRI images in both cases after brain death. MRI, showing us the anatomical changes of the brain, clearly revealed brain herniations, even though only nuclear findings of 'brain tamponade' were seen on CT. But in Case 1, we could not see the infarct lesions in the cerebellum on MR images obtained after brain death. This phenomenon was caused by the whole brain ischemia masking the initial ischemic lesions. We concluded that MRI was useful not only the anatomical display of lesions and brain herniation with high contrast resolution but for obtaining information on cerebral circulation of brain death. (author)

Clinical neuroanatomy - cranial MRI and CT. 4. rev. and enl. ed.

International Nuclear Information System (INIS)

Lanfermann, Heinrich; Raab, Peter; Kretschmann, Hans-Joachim; Weinrich, Wolfgang

2015-01-01

The book on clinical neuroanatomy - cranial MRI and CT covers the following issues: layered imaging diagnostics and reference structures; frontal layer, sagittal layers, transverse layers, brainstem, skull topography and the intracranial spaces and structures, facial skull topography, head-neck topography; neurofunctional systems, neurotransmitter and neuromodulators, surveillance material and techniques.

Clinical experience with MRI in head trauma cases

International Nuclear Information System (INIS)

Yamagami, Tatsuhito; Goto, Yasunobu; Kinuta, Yuji; Tashiro, Yuzuru; Nishihara, Kiyoshi; Hashimoto, Kenji; Minamikawa, Jun; Kikuchi, Haruhiko; Imataka, Kiyoharu.

1988-01-01

The ability to identify lesions after head trauma using magnetic resonance imaging (MRI) was tested in 199 cases. A resistive-type MRI scanner operating at a field of 0.2 Tesla was utilized in inversion-recovery (IR) and saturation-recovery (SR) radiofrequency-pulse sequences. Of the total number of cases, 54 were examined within 4 days after injury. An intracranial hematoma was removed in 47 cases. The MRI findings were normal in the cases of cerebral concussion, even in the presence of skull fracture. High intensity areas were seen in the SR images in 12 cases which were normal on X-ray CT. Both acute and subacute non-hemorrhagic contusion sites were visible as low intensity areas on the T 1 -weighted images and as high intensity areas on the SR images. Acute hemorrhagic contusion sites were visible as isointense and low intensity areas in the T 1 -weighted images and as high intensity areas in the SR images. Subacute sites appeared as high intensity areas in the T 1 -weighted, SR, and T 2 -weighted images. Direct coronal and sagittal views were adequate for the recognition of the three-dimensional brain structure. MRI was useful in the identification of brain contusion, in postoperative follow-ups, and in the detection of complications in the chronic stage. In the follow-up of 48 brain contusion cases, 13 cases showed normalized MRI findings and 9 cases showed improved findings. The recovery of cerebral function in these cases was good. The lesions demonstrated by MRI were considered to be contusional hematoma, petechiae, brain edema, shear injury, and non-hemorrhagic contusion. When they persist, such lesions are thought to change into such conditions as scar, gliosis, porencephaly, and brain atrophy. (author)

Comparison of diffusion-weighted fMRI and BOLD fMRI responses in a verbal working memory task

International Nuclear Information System (INIS)

Aso, Toshihiko; Urayama, Shin-ichi; Fukuyama, Hidenao; Le Bihan, Denis

2013-01-01

Diffusion-weighted functional MRI (DfMRI) has been reported to have a different response pattern in the visual cortex than that of BOLD-fMRI. Especially, the DfMRI signal shows a constantly faster response at both onset and offset of the stimulus, suggesting that the DfMRI signal might be more directly linked to neuronal events than the hemodynamic response. However, because the DfMRI response also contains a residual sensitivity to BOLD this hypothesis has been challenged. Using a verbal working memory task we show that the DfMRI time-course features are preserved outside visual cortices, but also less liable to between-subject/between-regional variation than the BOLD response. The overall findings not only support the feasibility of DfMRI as an approach for functional brain imaging, but also strengthen the uniqueness of the DfMRI signal origin. (authors)

MRI diagnosis of meningovascular neurosyphilis

International Nuclear Information System (INIS)

Chen Shuang; Qian Jianguo; Feng Xiaoyuan

2005-01-01

Objective: To evaluate the value and limitation of MRI in the diagnosis of meningovascular neurosyphilis. Methods: Five cases of neurosyphilis confirmed by clinical history/laboratory were examined with MRI (3 plain MRI, 2 enhanced MRI). The results of blood and CSF TPPA/RPR were positive and HIV was negative. Results: Abnormal signals were demonstrated in the temporal lobe in 3 cases, and infarction was revealed in the basal ganglion and periventricular white matter in another 2 cases. There was no marked contrast enhancement in the 2 cases. Conclusion: Meningovascular neurosyphilis has no characteristic features on MRI, but MRI is an effective method in delineating the size, range, and characters of neurosyphilis, and it is also an useful modality to follow-up after antibiotic therapy. (authors)

3D printing of MRI compatible components: why every MRI research group should have a low-budget 3D printer.

Science.gov (United States)

Herrmann, Karl-Heinz; Gärtner, Clemens; Güllmar, Daniel; Krämer, Martin; Reichenbach, Jürgen R

2014-10-01

To evaluate low budget 3D printing technology to create MRI compatible components. A 3D printer is used to create customized MRI compatible components, a loop-coil platform and a multipart mouse fixation. The mouse fixation is custom fit for a dedicated coil and facilitates head fixation with bite bar, anesthetic gas supply and biomonitoring sensors. The mouse fixation was tested in a clinical 3T scanner. All parts were successfully printed and proved MR compatible. Both design and printing were accomplished within a few days and the final print results were functional with well defined details and accurate dimensions (Δ3D printer can be used to quickly progress from a concept to a functional device at very low production cost. While 3D printing technology does impose some restrictions on model geometry, additive printing technology can create objects with complex internal structures that can otherwise not be created by using lathe technology. Thus, we consider a 3D printer a valuable asset for MRI research groups. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

MRI in acute poliomyelitis

Energy Technology Data Exchange (ETDEWEB)

Kornreich, L. [Imaging Department, The Schneider Children`s Medical Centre of Israel, Kaplan Street, Petah Tiqva 49202 (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel); Dagan, O. [The Intensive Care Unit, The Schneider Children`s Medical Centre of Israel, Beilinson Medical Campus, Petah Tiqva (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel); Grunebaum, M. [Imaging Department, The Schneider Children`s Medical Centre of Israel, Kaplan Street, Petah Tiqva 49202 (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel)

1996-05-01

MRI can be used in the diagnosis of anterior horn infection and for assessing the extent of disease. There are no specific MRI signs to differentiate between the various possible pathogens. This is demonstrated in the present case of poliomyelitis, in which MRI of the spine played an important role in establishing the diagnosis. (orig.). With 1 fig.

MRI in acute poliomyelitis

International Nuclear Information System (INIS)

Kornreich, L.; Dagan, O.; Grunebaum, M.

1996-01-01

MRI can be used in the diagnosis of anterior horn infection and for assessing the extent of disease. There are no specific MRI signs to differentiate between the various possible pathogens. This is demonstrated in the present case of poliomyelitis, in which MRI of the spine played an important role in establishing the diagnosis. (orig.). With 1 fig

Prospective comparison of T2w-MRI and dynamic-contrast-enhanced MRI, 3D-MR spectroscopic imaging or diffusion-weighted MRI in repeat TRUS-guided biopsies

Energy Technology Data Exchange (ETDEWEB)

Portalez, Daniel [Clinique Pasteur, 45, Department of Radiology, Toulouse (France); Rollin, Gautier; Mouly, Patrick; Jonca, Frederic; Malavaud, Bernard [Hopital de Rangueil, Department of Urology, Toulouse Cedex 9 (France); Leandri, Pierre [Clinique Saint Jean, 20, Department of Urology, Toulouse (France); Elman, Benjamin [Clinique Pasteur, 45, Department of Urology, Toulouse (France)

2010-12-15

To compare T2-weighted MRI and functional MRI techniques in guiding repeat prostate biopsies. Sixty-eight patients with a history of negative biopsies, negative digital rectal examination and elevated PSA were imaged before repeat biopsies. Dichotomous criteria were used with visual validation of T2-weighted MRI, dynamic contrast-enhanced MRI and literature-derived cut-offs for 3D-spectroscopy MRI (choline-creatine-to-citrate ratio >0.86) and diffusion-weighted imaging (ADC x 10{sup 3} mm{sup 2}/s < 1.24). For each segment and MRI technique, results were rendered as being suspicious/non-suspicious for malignancy. Sextant biopsies, transition zone biopsies and at least two additional biopsies of suspicious areas were taken. In the peripheral zones, 105/408 segments and in the transition zones 19/136 segments were suspicious according to at least one MRI technique. A total of 28/68 (41.2%) patients were found to have cancer. Diffusion-weighted imaging exhibited the highest positive predictive value (0.52) compared with T2-weighted MRI (0.29), dynamic contrast-enhanced MRI (0.33) and 3D-spectroscopy MRI (0.25). Logistic regression showed the probability of cancer in a segment increasing 12-fold when T2-weighted and diffusion-weighted imaging MRI were both suspicious (63.4%) compared with both being non-suspicious (5.2%). The proposed system of analysis and reporting could prove clinically relevant in the decision whether to repeat targeted biopsies. (orig.)

MRI-based quantification of brain damage in cerebrovascular disorders

NARCIS (Netherlands)

de Bresser, J.H.J.M.

2011-01-01

Brain diseases can lead to diverse structural abnormalities that can be assessed on magnetic resonance imaging (MRI) scans. These abnormalities can be quantified by (semi-)automated techniques. The studies described in this thesis aimed to optimize and apply cerebral quantification techniques in

Epileptogenic developmental venous anomaly: insights from simultaneous EEG/fMRI.

Science.gov (United States)

Scheidegger, Olivier; Wiest, Roland; Jann, Kay; König, Thomas; Meyer, Klaus; Hauf, Martinus

2013-04-01

Developmental venous anomalies (DVAs) are associated with epileptic seizures; however, the role of DVA in the epileptogenesis is still not established. Simultaneous interictal electroencephalogram/functional magnetic resonance imaging (EEG/fMRI) recordings provide supplementary information to electroclinical data about the epileptic generators, and thus aid in the differentiation of clinically equivocal epilepsy syndromes. The main objective of our study was to characterize the epileptic network in a patient with DVA and epilepsy by simultaneous EEG/fMRI recordings. A 17-year-old woman with recently emerging generalized tonic-clonic seizures, and atypical generalized discharges, was investigated using simultaneous EEG/fMRI at the university hospital. Previous high-resolution MRI showed no structural abnormalities, except a DVA in the right frontal operculum. Interictal EEG recordings showed atypical generalized discharges, corresponding to positive focal blood oxygen level dependent (BOLD) correlates in the right frontal operculum, a region drained by the DVA. Additionally, widespread cortical bilateral negative BOLD correlates in the frontal and parietal lobes were delineated, resembling a generalized epileptic network. The EEG/fMRI recordings support a right frontal lobe epilepsy, originating in the vicinity of the DVA, propagating rapidly to both frontal and parietal lobes, as expressed on the scalp EEG by secondary bilateral synchrony. The DVA may be causative of focal epilepsies in cases where no concomitant epileptogenic lesions can be detected. Advanced imaging techniques, such as simultaneous EEG/fMRI, may thus aid in the differentiation of clinically equivocal epilepsy syndromes.

Can unenhanced multiparametric MRI substitute gadolinium-enhanced MRI in the characterization of vertebral marrow infiltrative lesions?

Directory of Open Access Journals (Sweden)

Dalia Z. Zidan

2014-06-01

Conclusion: Unenhanced-multiparametric MRI is compatible with gadolinium-enhanced MRI in reliable characterization of marrow infiltrative lesions. The routine MRI protocol of cancer patients should be altered to accommodate the evolving MRI technology and cost effectively substitute the need for a gadolinium enhanced scan.

Is fMRI “noise” really noise? Resting state nuisance regressors remove variance with network structure

Science.gov (United States)

Bright, Molly G.; Murphy, Kevin

2015-01-01

Noise correction is a critical step towards accurate mapping of resting state BOLD fMRI connectivity. Noise sources related to head motion or physiology are typically modelled by nuisance regressors, and a generalised linear model is applied to regress out the associated signal variance. In this study, we use independent component analysis (ICA) to characterise the data variance typically discarded in this pre-processing stage in a cohort of 12 healthy volunteers. The signal variance removed by 24, 12, 6, or only 3 head motion parameters demonstrated network structure typically associated with functional connectivity, and certain networks were discernable in the variance extracted by as few as 2 physiologic regressors. Simulated nuisance regressors, unrelated to the true data noise, also removed variance with network structure, indicating that any group of regressors that randomly sample variance may remove highly structured “signal” as well as “noise.” Furthermore, to support this we demonstrate that random sampling of the original data variance continues to exhibit robust network structure, even when as few as 10% of the original volumes are considered. Finally, we examine the diminishing returns of increasing the number of nuisance regressors used in pre-processing, showing that excessive use of motion regressors may do little better than chance in removing variance within a functional network. It remains an open challenge to understand the balance between the benefits and confounds of noise correction using nuisance regressors. PMID:25862264

Structural Findings in the Brain MRI of Patients with Acute Carbon Monoxide Poisoning

Directory of Open Access Journals (Sweden)

Yasmin Davoudi

2014-09-01

Conclusion: The white matter and globus pallidus were the most common affected regions in brain following acute CO poisoning. Signal abnormalities and restricted diffusion in MRI were correlated with duration of exposure to CO but not with the carboxyhemoglobin levels.

Low-field MRI can be more sensitive than high-field MRI

Science.gov (United States)

Coffey, Aaron M.; Truong, Milton L.; Chekmenev, Eduard Y.

2013-12-01

MRI signal-to-noise ratio (SNR) is the key factor for image quality. Conventionally, SNR is proportional to nuclear spin polarization, which scales linearly with magnetic field strength. Yet ever-stronger magnets present numerous technical and financial limitations. Low-field MRI can mitigate these constraints with equivalent SNR from non-equilibrium ‘hyperpolarization' schemes, which increase polarization by orders of magnitude independently of the magnetic field. Here, theory and experimental validation demonstrate that combination of field independent polarization (e.g. hyperpolarization) with frequency optimized MRI detection coils (i.e. multi-turn coils using the maximum allowed conductor length) results in low-field MRI sensitivity approaching and even rivaling that of high-field MRI. Four read-out frequencies were tested using samples with identical numbers of 1H and 13C spins. Experimental SNRs at 0.0475 T were ∼40% of those obtained at 4.7 T. Conservatively, theoretical SNRs at 0.0475 T 1.13-fold higher than those at 4.7 T were possible despite an ∼100-fold lower detection frequency, indicating feasibility of high-sensitivity MRI without technically challenging, expensive high-field magnets. The data at 4.7 T and 0.0475 T was obtained from different spectrometers with different RF probes. The SNR comparison between the two field strengths accounted for many differences in parameters such as system noise figures and variations in the probe detection coils including Q factors and coil diameters.

MRI or not to MRI! Should brain MRI be a routine investigation in children with autistic spectrum disorders?

Science.gov (United States)

Zeglam, Adel M; Al-Ogab, Marwa F; Al-Shaftery, Thouraya

2015-09-01

To evaluate the routine usage of Magnetic Resonance Imaging (MRI) of brain and estimate the prevalence of brain abnormalities in children presenting to the Neurodevelopment Clinic of Al-Khadra Hospital (NDC-KH), Tripoli, Libya with autistic spectrum disorders (ASD). The records of all children with ASD presented to NDC-KH over 4-year period (from January 2009 to December 2012) were reviewed. All MRIs were acquired with a 1.5-T Philips (3-D T1, T2, FLAIR coronal and axial sequences). MRIs were reported to be normal, abnormal or no significant abnormalities by a consultant neuroradiologist. One thousand and seventy-five children were included in the study. Seven hundred and eighty-two children (72.7 %) had an MRI brain of whom 555 (71 %) were boys. 26 children (24 males and 2 females) (3.3 %) demonstrated MRI abnormalities (8 leukodystrophic changes, 4 periventricular leukomalacia, 3 brain atrophy, 2 tuberous sclerosis, 2 vascular changes, 1 pineoblastoma, 1 cerebellar angioma, 1 cerebellar hypoplasia, 3 agenesis of corpus callosum, 1 neuro-epithelial cyst). An unexpectedly high rate of MRI abnormalities was found in the first large series of clinical MRI investigations in children with autism. These results could contribute to further research into the pathogenesis of autistic spectrum disorder.

Benefits of sagittal-oblique MRI reconstruction of anterior cruciate ligament of the knee

International Nuclear Information System (INIS)

Nenezić, D.

2015-01-01

Full text: MRI examination of the anterior cruciate ligament (ACL) of the knee gives valuable information for conventional, physiatrist and/or arthroscopic microinvasiv treatment. three planar MRI examination and 3D reconstructions are highly precise in the analysis of the intra and periarticular structures, with exceptions of anterior cruciate ligament. Direct contact with the roof of the intercondilar fossa (in the full extension during the examination) and its specific orientation makes visualization of ACL diagnostically problematic. In a one year period precise protocol for MRI visualization of ACL was tested and applied as “Sagittal Oblique MRI Reconstruction”. In short, it has been Angled biplanar reconstruction in the parasagital and paratransversal planes (patientrelated and arbitrary selected in full extension), on T2, 2mm slice and 0,2 mm gap. 153 MRI examinations of the patients with lesions of the ACL were included in the study in the Clinical Center of Montenegro during 2005 year. Beside standard Knee MRI protocol all patients had the Sagittal Oblique MRI reconstruction of ACL and the Flexion MRI examination, to compare with. The Sagittal Oblique MRI reconstruction of ACL it is adapted to the concrete morphology of the patients ACL and it does not depend of the volume of the examined knee. In comparison with the Standard Knee MRI protocol and with the Flexion MRI examination, the Sagittal Oblique MRI reconstruction of ACL takes less time to perform, and the ligament is shown in fool length at three to five slices, which is more than with the both compared protocols. Sagittal Oblique MRI Reconstruction of ACL is therefore patient dependable, orientated in shape of concrete ligament of the patient’s knee. In combination with age, occupation, physical activity and level of patients while to contribute in healing process, the Sagittal Oblique MRI reconstruction of ACL contribute to scholastic approach, as highest benefit to patients with

MRI in assessing children with learning disability, focal findings, and reduced automaticity.

Science.gov (United States)

Urion, David K; Huff, Hanalise V; Carullo, Maria Paulina

2015-08-18

In children with clinically diagnosed learning disabilities with focal findings on neurologic or neuropsychological evaluations, there is a hypothesized association between disorders in automaticity and focal structural abnormalities observed in brain MRIs. We undertook a retrospective analysis of cases referred to a tertiary-hospital-based learning disabilities program. Individuals were coded as having a focal deficit if either neurologic or neuropsychological evaluation demonstrated focal dysfunction. Those with abnormal MRI findings were categorized based on findings. Children with abnormalities from each of these categories were compared in terms of deficits in automaticity, as measured by the tasks of Rapid Automatized Naming, Rapid Alternating Stimulus Naming, or the timed motor performance battery from the Physical and Neurological Examination for Soft Signs. Data were compared in children with and without disorders of automaticity regarding type of brain structure abnormality. Of the 1,587 children evaluated, 127 had a focal deficit. Eighty-seven had a brain MRI (52 on 1.5-tesla machines and 35 on 3.0-tesla machines). Forty of these images were found to be abnormal. These children were compared with a clinic sample of 150 patients with learning disabilities and no focal findings on examination, who also had undergone MRI. Only 5 of the latter group had abnormalities on MRI. Reduced verbal automaticity was associated with cerebellar abnormalities, whereas reduced automaticity on motor or motor and verbal tasks was associated with white matter abnormalities. Reduced automaticity of retrieval and slow timed motor performance appear to be highly associated with MRI findings. © 2015 American Academy of Neurology.

Seizure-induced brain lesions: A wide spectrum of variably reversible MRI abnormalities

International Nuclear Information System (INIS)

Cianfoni, A.; Caulo, M.; Cerase, A.; Della Marca, G.; Falcone, C.; Di Lella, G.M.; Gaudino, S.; Edwards, J.; Colosimo, C.

2013-01-01

Introduction MRI abnormalities in the postictal period might represent the effect of the seizure activity, rather than its structural cause. Material and Methods Retrospective review of clinical and neuroimaging charts of 26 patients diagnosed with seizure-related MR-signal changes. All patients underwent brain-MRI (1.5-Tesla, standard pre- and post-contrast brain imaging, including DWI-ADC in 19/26) within 7 days from a seizure and at least one follow-up MRI, showing partial or complete reversibility of the MR-signal changes. Extensive clinical work-up and follow-up, ranging from 3 months to 5 years, ruled out infection or other possible causes of brain damage. Seizure-induced brain-MRI abnormalities remained a diagnosis of exclusion. Site, characteristics and reversibility of MRI changes, and association with characteristics of seizures were determined. Results MRI showed unilateral (13/26) and bilateral abnormalities, with high (24/26) and low (2/26) T2-signal, leptomeningeal contrast-enhancement (2/26), restricted diffusion (9/19). Location of abnormality was cortical/subcortical, basal ganglia, white matter, corpus callosum, cerebellum. Hippocampus was involved in 10/26 patients. Reversibility of MRI changes was complete in 15, and with residual gliosis or focal atrophy in 11 patients. Reversibility was noted between 15 and 150 days (average, 62 days). Partial simple and complex seizures were associated with hippocampal involvement (p = 0.015), status epilepticus with incomplete reversibility of MRI abnormalities (p = 0.041). Conclusions Seizure or epileptic status can induce transient, variably reversible MRI brain abnormalities. Partial seizures are frequently associated with hippocampal involvement and status epilepticus with incompletely reversible lesions. These seizure-induced MRI abnormalities pose a broad differential diagnosis; increased awareness may reduce the risk of misdiagnosis and unnecessary intervention

Seizure-induced brain lesions: A wide spectrum of variably reversible MRI abnormalities

Energy Technology Data Exchange (ETDEWEB)

Cianfoni, A., E-mail: acianfoni@hotmail.com [Neuroradiology, Neurocenter of Italian Switzerland–Ospedale regionale Lugano, Via Tesserete 46, Lugano, 6900, CH (Switzerland); Caulo, M., E-mail: caulo@unich.it [Department of Neuroscience and Imaging, University of Chieti, Via dei Vestini 33, 6610 Chieti. Italy (Italy); Cerase, A., E-mail: alfonsocerase@gmail.com [Unit of Neuroimaging and Neurointervention NINT, Department of Neurological and Sensorineural Sciences, Azienda Ospedaliera Universitaria Senese, Policlinico “Santa Maria alle Scotte”, V.le Bracci 16, Siena (Italy); Della Marca, G., E-mail: dellamarca@rm.unicatt.it [Neurology Dept., Catholic University of Rome, L.go F Vito 1, 00100, Rome (Italy); Falcone, C., E-mail: carlo_falc@libero.it [Radiology Dept., Catholic University of Rome, L.go F Vito 1, 00100, Rome (Italy); Di Lella, G.M., E-mail: gdilella@rm.unicatt.it [Radiology Dept., Catholic University of Rome, L.go F Vito 1, 00100, Rome (Italy); Gaudino, S., E-mail: sgaudino@sirm.org [Radiology Dept., Catholic University of Rome, L.go F Vito 1, 00100, Rome (Italy); Edwards, J., E-mail: edwardjc@musc.edu [Neuroscience Dept., Medical University of South Carolina, 96J Lucas st, 29425, Charleston, SC (United States); Colosimo, C., E-mail: colosimo@rm.unicatt.it [Radiology Dept., Catholic University of Rome, L.go F Vito 1, 00100, Rome (Italy)

2013-11-01

Introduction MRI abnormalities in the postictal period might represent the effect of the seizure activity, rather than its structural cause. Material and Methods Retrospective review of clinical and neuroimaging charts of 26 patients diagnosed with seizure-related MR-signal changes. All patients underwent brain-MRI (1.5-Tesla, standard pre- and post-contrast brain imaging, including DWI-ADC in 19/26) within 7 days from a seizure and at least one follow-up MRI, showing partial or complete reversibility of the MR-signal changes. Extensive clinical work-up and follow-up, ranging from 3 months to 5 years, ruled out infection or other possible causes of brain damage. Seizure-induced brain-MRI abnormalities remained a diagnosis of exclusion. Site, characteristics and reversibility of MRI changes, and association with characteristics of seizures were determined. Results MRI showed unilateral (13/26) and bilateral abnormalities, with high (24/26) and low (2/26) T2-signal, leptomeningeal contrast-enhancement (2/26), restricted diffusion (9/19). Location of abnormality was cortical/subcortical, basal ganglia, white matter, corpus callosum, cerebellum. Hippocampus was involved in 10/26 patients. Reversibility of MRI changes was complete in 15, and with residual gliosis or focal atrophy in 11 patients. Reversibility was noted between 15 and 150 days (average, 62 days). Partial simple and complex seizures were associated with hippocampal involvement (p = 0.015), status epilepticus with incomplete reversibility of MRI abnormalities (p = 0.041). Conclusions Seizure or epileptic status can induce transient, variably reversible MRI brain abnormalities. Partial seizures are frequently associated with hippocampal involvement and status epilepticus with incompletely reversible lesions. These seizure-induced MRI abnormalities pose a broad differential diagnosis; increased awareness may reduce the risk of misdiagnosis and unnecessary intervention.

Magnetic resonance imaging of the triangular fibrocartilage complex. Usefulness of the fat suppression MRI

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Toshiyasu [Fujita Health Univ., Nagoya (Japan). Second Hospital; Yabe, Yutaka; Horiuchi, Yukio; Kikuchi, Yoshito; Makita, Satoo

1996-08-01

Advances in magnetic resonance imaging (MRI) now allow for the visualization of small structures, such as the triangular fibrocartilage complex (TFCC) of the wrist. Recent investigators suggested that MRI is useful in delineation of the TFCC itself and its abnormality, and supported that diagnostic value of MRI for the TFCC tears is almost equal to those of arthrography and arthroscopy. In contrast, there were several reports that representation of the TFCC in MRI was less worth than in arthrography. Further, it was reported that MRI was not useful because abnormal findings existed at normal volunteers` wrists. Recent development of the pulse sequence is remarkable, such as gradient echo, fast spin echo and fat suppression method. However, as the previous MR studies of the TFCC mainly using conventional spin echo pulse sequence, there were a few comparison of each pulse sequence and we do not know how each pulse sequence delineates the TFCC. Therefore, we studied MRI of the TFCC using several pulse sequence in normal volunteers, and compared MR slices of the TFCC with corresponding histological sections to evaluate shape detectability of MRI. (J.P.N.)

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... does not completely surround you. Some newer MRI machines have a larger diameter bore which can be ... size patients or patients with claustrophobia. Other MRI machines are open on the sides (open MRI). Open ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... information on the chemicals present in the body's cells, may also be performed during the MRI exam ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... in the first three to four months of pregnancy unless the potential benefit from the MRI exam ... the MRI Safety page for more information about pregnancy and MRI. If you have claustrophobia (fear of ...

3 telsa MRI: successful results with higher field strengths

International Nuclear Information System (INIS)

Schmitt, F.; Grosu, D.; Purdy, D.; Salem, K.; Scott, K.T.; Stoeckel, B.; Mohr, C.

2004-01-01

The recent development of 3Telsa MRI (3T MRI) has been fueled by the promise of increased signal-to-noise ratio (SNR). Many are excited about the opportunity to no only use the increased SNR for clearer images, but also the change to exchange it for better resolution or faster scans. These possibilities have caused a rapid increase in the market for 3T MRI, where the faster scanning tips an already advantageous economic outlook in favor of the user. As a result, the global market for 3T has grown from a research only market just a few years ago to an ever-increasing clinically oriented customer base. There are, however, significant obstacles to 3T MRI presented by the physics at higher field strength. For example the T1 relaxation times are prolongued with increasing magnet field strength. Further, the increased RF-energy deposition (ASR), the larger chemical shift and the stronger susceptibility effect have to be considered as challenges. It is critical that one looks at both the advantages and disadvantages of using 3T. While there are many issues to address and a number of different methods for doing so, to properly tackle each of these concerns will take time and effort on the part of researchers and clinicians. The optimization of 3T MRI scanning will have to be combined effort, though much work has already been done. The most active area of work to date has been in neuroimaging. Multiple applications have been explored in addition to clinical anatomical imaging, where resolutions is improved showing structure in the brain never before seen in human MRI

Decoding subjective mental states from fMRI activity patterns

International Nuclear Information System (INIS)

Tamaki, Masako; Kamitani, Yukiyasu

2011-01-01

In recent years, functional magnetic resonance imaging (fMRI) decoding has emerged as a powerful tool to read out detailed stimulus features from multi-voxel brain activity patterns. Moreover, the method has been extended to perform a primitive form of 'mind-reading,' by applying a decoder 'objectively' trained using stimulus features to more 'subjective' conditions. In this paper, we first introduce basic procedures for fMRI decoding based on machine learning techniques. Second, we discuss the source of information used for decoding, in particular, the possibility of extracting information from subvoxel neural structures. We next introduce two experimental designs for decoding subjective mental states: the 'objective-to-subjective design' and the 'subjective-to-subjective design.' Then, we illustrate recent studies on the decoding of a variety of mental states, such as, attention, awareness, decision making, memory, and mental imagery. Finally, we discuss the challenges and new directions of fMRI decoding. (author)

MRI-Based Nonrigid Motion Correction in Simultaneous PET/MRI

Science.gov (United States)

Chun, Se Young; Reese, Timothy G.; Ouyang, Jinsong; Guerin, Bastien; Catana, Ciprian; Zhu, Xuping; Alpert, Nathaniel M.; El Fakhri, Georges

2014-01-01

Respiratory and cardiac motion is the most serious limitation to whole-body PET, resulting in spatial resolution close to 1 cm. Furthermore, motion-induced inconsistencies in the attenuation measurements often lead to significant artifacts in the reconstructed images. Gating can remove motion artifacts at the cost of increased noise. This paper presents an approach to respiratory motion correction using simultaneous PET/MRI to demonstrate initial results in phantoms, rabbits, and nonhuman primates and discusses the prospects for clinical application. Methods Studies with a deformable phantom, a free-breathing primate, and rabbits implanted with radioactive beads were performed with simultaneous PET/MRI. Motion fields were estimated from concurrently acquired tagged MR images using 2 B-spline nonrigid image registration methods and incorporated into a PET list-mode ordered-subsets expectation maximization algorithm. Using the measured motion fields to transform both the emission data and the attenuation data, we could use all the coincidence data to reconstruct any phase of the respiratory cycle. We compared the resulting SNR and the channelized Hotelling observer (CHO) detection signal-to-noise ratio (SNR) in the motion-corrected reconstruction with the results obtained from standard gating and uncorrected studies. Results Motion correction virtually eliminated motion blur without reducing SNR, yielding images with SNR comparable to those obtained by gating with 5–8 times longer acquisitions in all studies. The CHO study in dynamic phantoms demonstrated a significant improvement (166%–276%) in lesion detection SNR with MRI-based motion correction as compared with gating (P < 0.001). This improvement was 43%–92% for large motion compared with lesion detection without motion correction (P < 0.001). CHO SNR in the rabbit studies confirmed these results. Conclusion Tagged MRI motion correction in simultaneous PET/MRI significantly improves lesion detection

CT and MRI matching for radiotherapy planning in head and neck cancer

Energy Technology Data Exchange (ETDEWEB)

Rasch, C; Keus, R; Touw, A; Lebesque, J; Van Herk, M [Nederlands Kanker Inst. ` Antoni van Leeuwenhoekhuis` , Amsterdam (Netherlands)

1995-12-01

The objective of this study was to evaluate the impact of matched CT and MRI information on target delineation in radiotherapy planning for head and neck tumors. MRI images of eight patients with head and neck cancer in supine position, not necessarily obtained in radiotherapy treatment position were matched to the CT scans made in radiotherapy position using automatic three-dimensional chamfer-matching of bony structures. Four independent observers delineated the Gross Tumor Volume (GTV) in CT scans and axial and sagittal MR scans. The GTV`s were compared, overlapping volumes and non-overlapping volumes between the different datasets and observers were determined. In all patients a good match of CT and MRI information was accomplished in the head region. The combined information provided a better visualisation of the GTV, oedema and normal tissues compared with CT or MRI alone. Determination of overlapping and non-overlapping volumes proved to be a valuable tool to measure uncertainties in the determination of the GTV. CT-MRI matching in patients with head and neck tumors is feasible and makes a more accurate irradiation with higher tumor doses and less normal tissue complications possible. Remaining uncertainties in the determination of the GTV can be quantified using the combined information of MRI and CT.

Numerical study on simultaneous emission and transmission tomography in the MRI framework

Science.gov (United States)

Gjesteby, Lars; Cong, Wenxiang; Wang, Ge

2017-09-01

Multi-modality imaging methods are instrumental for advanced diagnosis and therapy. Specifically, a hybrid system that combines computed tomography (CT), nuclear imaging, and magnetic resonance imaging (MRI) will be a Holy Grail of medical imaging, delivering complementary structural/morphological, functional, and molecular information for precision medicine. A novel imaging method was recently demonstrated that takes advantage of radiotracer polarization to combine MRI principles with nuclear imaging. This approach allows the concentration of a polarized Υ-ray emitting radioisotope to be imaged with MRI resolution potentially outperforming the standard nuclear imaging mode at a sensitivity significantly higher than that of MRI. In our work, we propose to acquire MRI-modulated nuclear data for simultaneous image reconstruction of both emission and transmission parameters, suggesting the potential for simultaneous CT-SPECT-MRI. The synchronized diverse datasets allow excellent spatiotemporal registration and unique insight into physiological and pathological features. Here we describe the methodology involving the system design with emphasis on the formulation for tomographic images, even when significant radiotracer signals are limited to a region of interest (ROI). Initial numerical results demonstrate the feasibility of our approach for reconstructing concentration and attenuation images through a head phantom with various radio-labeled ROIs. Additional considerations regarding the radioisotope characteristics are also discussed.

Neuroradiological findings in primary progressive aphasia: CT, MRI and cerebral perfusion SPECT

International Nuclear Information System (INIS)

Sinnatamby, R.; Antoun, N.A.; Freer, C.E.L.; Miles, K.A.; Hodges, J.R.

1996-01-01

Primary progressive aphasia (PPA) is defined as progressive decline in language for 2 or more years with preservation of activities of daily living and general cognitive functions. Whereas the clinical features of this syndrome have been well documented, the neuroradiological findings have not been studied systematically. We studied 13 patients with PPA retrospectively: 10 underwent CT, 12 MRI and 12 cerebral perfusion studies using 99m Tc-HMPAO SPECT. CT and MR images were scored for focal atrophy by two independent assessors. Initial qualitative assessment of SPECT images was confirmed by quantitative analysis. CY was normal in 5 patients. Focal atrophy, affecting predominantly the left temporal lobe, was seen in 4 of 10 patients on CT, and 10 of 12 on MRI. Atrophy was localised primarily to the superior and middle temporal gyri on MRI. All 12 patients who underwent SPECT had unilateral temporal lobe perfusion defects, in 2 patients of whom MRI was normal. CT is relatively insensitive to focal abnormalities in PPA; MRI and SPECT are the imaging modalities of choice. MRI allows accurate, specific localisation of atrophy with the temporal neocortex. SPECT may reveal a functional decrease in cerebral perfusion prior to establishment of structural change. (orig.)

Neuroradiological findings in primary progressive aphasia: CT, MRI and cerebral perfusion SPECT

Energy Technology Data Exchange (ETDEWEB)

Sinnatamby, R. [Dept. of Radiology, Addenbrooke`s Hospital NHS Trust, Cambridge (United Kingdom); Antoun, N.A. [Dept. of Radiology, Addenbrooke`s Hospital NHS Trust, Cambridge (United Kingdom); Freer, C.E.L. [Dept. of Radiology, Addenbrooke`s Hospital NHS Trust, Cambridge (United Kingdom); Miles, K.A. [Dept. of Nuclear Medicine, Addenbrooke`s Hospital NHS Trust, Cambridge (United Kingdom); Hodges, J.R. [Dept. of Neurology, Addenbrooke`s Hospital NHS Trust, Cambridge (United Kingdom)

1996-04-01

Primary progressive aphasia (PPA) is defined as progressive decline in language for 2 or more years with preservation of activities of daily living and general cognitive functions. Whereas the clinical features of this syndrome have been well documented, the neuroradiological findings have not been studied systematically. We studied 13 patients with PPA retrospectively: 10 underwent CT, 12 MRI and 12 cerebral perfusion studies using {sup 99m}Tc-HMPAO SPECT. CT and MR images were scored for focal atrophy by two independent assessors. Initial qualitative assessment of SPECT images was confirmed by quantitative analysis. CY was normal in 5 patients. Focal atrophy, affecting predominantly the left temporal lobe, was seen in 4 of 10 patients on CT, and 10 of 12 on MRI. Atrophy was localised primarily to the superior and middle temporal gyri on MRI. All 12 patients who underwent SPECT had unilateral temporal lobe perfusion defects, in 2 patients of whom MRI was normal. CT is relatively insensitive to focal abnormalities in PPA; MRI and SPECT are the imaging modalities of choice. MRI allows accurate, specific localisation of atrophy with the temporal neocortex. SPECT may reveal a functional decrease in cerebral perfusion prior to establishment of structural change. (orig.)

Surgical considerations when reporting MRI studies of soft tissue sarcoma of the limbs

Energy Technology Data Exchange (ETDEWEB)

De la Hoz Polo, Marcela [Kings College Hospital, Radiology Department, London, Brixton (United Kingdom); Dick, Elizabeth [St Mary' s Hospital, Imperial College Healthcare NHS Trust, Radiology Department, London (United Kingdom); Bhumbra, Rej [Newham and The Royal London Hospitals, Trauma and Orthopaedic Department, Barts Health Orthopaedic Centre, London, Whitechapel (United Kingdom); Pollock, Rob [Royal National Orthopaedic Hospital, Trauma and Orthopaedic Department, Stanmore (United Kingdom); Sandhu, Ranbir [University Hospitals Birmingham, Radiology Department, Queen Elizabeth Hospital, Birmingham (United Kingdom); Saifuddin, Asif [Royal National Orthopaedic Hospital, Radiology Department, Stanmore (United Kingdom)

2017-12-15

Soft tissue sarcomas (STS) are rare tumours that require prompt diagnosis and treatment at a specialist centre. Magnetic resonance imaging (MRI) has become the modality of choice for identification, characterisation, biopsy planning and staging of soft tissue masses. MRI enables both the operating surgeon and patient to be optimally prepared prior to surgery for the likelihood of margin-negative resection and to anticipate possible sacrifice of adjacent structures and consequent loss of function. The aim of this review is to aid the radiologist in performing and reporting MRI studies of soft tissue sarcomas, with particular reference to the requirements of the surgical oncologist. (orig.)

Structural and Functional MRI Differences in Master Sommeliers: A pilot study on expertise in the brain

Directory of Open Access Journals (Sweden)

Sarah Jane Banks

2016-08-01

Full Text Available Our experiences, even as adults, shape our brains. Regional differences have been found in experts, with the regions associated with their particular skill-set. Functional differences have also been noted in brain activation patterns in some experts. This study uses multimodal techniques to assess structural and functional patterns that differ between experts and nonexperts. Sommeliers are experts in wine and thus in olfaction. We assessed differences in Master Sommeliers’ brains, compared with controls, in structure and also in functional response to olfactory and visual judgment tasks. MRI data were analyzed using voxel-based morphometry as well as automated parcellation to assess structural properties, and group differences between tasks were calculated. Results indicate enhanced volume in the right insula and entorhinal cortex, with the cortical thickness of the entorhinal correlating with experience. There were regional activation differences in a large area involving the right olfactory and memory regions, with heightened activation specifically for sommeliers during an olfactory task. Our results indicate that sommeliers’ brains show specialization in the expected regions of the olfactory and memory networks, and also in regions important in integration of internal sensory stimuli and external cues. Overall, these differences suggest that specialized expertise and training might result in enhancements in the brain well into adulthood. This is particularly important given the regions involved, which are the first to be impacted by many neurodegenerative diseases.

[MRI for brain structure and function in patients with first-episode panic disorder].

Science.gov (United States)

Zhang, Yan; Duan, Lian; Liao, Mei; Yang, Fan; Liu, Jun; Shan, Baoci; Li, Lingjiang

2011-12-01

To determine the brain function and structure in patinets with first-episode panic disorder (PD). All subjects (24 PD patients and 24 healthy subjects) received MRI scan and emotional counting Stroop task during the functional magnetic resonance imaging. Blood oxygenation level dependent functional magnetic resonance imaging and voxel-based morphometric technology were used to detect the gray matter volume. Compared with the healthy controls, left thalamus, left medial frontal gyrus, left anterior cingulate gyrus, left inferior frontal gyrus, left insula (panic-related words vs. neutral words) lacked activation in PD patients, but the over-activation were found in right brain stem, right occipital lobe/lingual gyrus in PD patients. Compared with the healthy controls, the gray matter volume in the PD patients significantly decreased in the left superior temporal gyrus, right medial frontal gyrus, left medial occipital gyrus, dorsomedial nucleus of left thalamus and right anterior cingulate gyrus. There was no significantly increased gray matter volume in any brain area in PD patients. PD patients have selective attentional bias in processing threatening information due to the depression and weakening of the frontal cingulated gyrus.

Magnetic Resonance Imaging (MRI) -- Head

Medline Plus

Full Text Available ... or patients with claustrophobia. Other MRI machines are open on the sides (open MRI). Open units are especially helpful for examining larger patients or those with claustrophobia. Newer open MRI units provide very high quality images for ...

MU-SYNTHESIS BASED ACTIVE ROBUST VIBRATION CONTROL OF AN MRI INLET

Directory of Open Access Journals (Sweden)

Atta Oveisi

2016-04-01

Full Text Available In this paper, a robust control technique based on μ-synthesis is employed in order to investigate the vibration control of a funnel-shaped structure that is used as the inlet of a magnetic resonance imaging (MRI device. MRI devices are widely subjected to the vibration of the magnetic gradient coil which then propagates to acoustic noise and leads to a series of clinical and mechanical problems. In order to address this issue and as a part of noise cancellation study in MRI devices, distributed piezo-transducers are bounded on the top surface of the funnel as functional sensor/actuator modules. Then, a reduced order linear time-invariant (LTI model of the piezolaminated structure in the state-space representation is estimated by means of a predictive error minimization (PEM algorithm as a subspace identification method based on the trust-region-reflective technique. The reduced order model is expanded by the introduction of appropriate frequency-dependent weighting functions that address the unmodeled dynamics and the augmented multiplicative modeling uncertainties of the system. Then, the standard D-K iteration algorithm as an output-feedback control method is used based on the nominal model with the subordinate uncertainty elements from the previous step. Finally, the proposed control system implemented experimentally on the real structure is to evaluate the robust vibration attenuation performance of the closed-loop system.

SU-E-J-193: Feasibility of MRI-Only Based IMRT Planning for Pancreatic Cancer

International Nuclear Information System (INIS)

Prior, P; Botros, M; Chen, X; Paulson, E; Erickson, B; Li, X

2014-01-01

Purpose: With the increasing use of MRI simulation and the advent of MRI-guided delivery, it is desirable to use MRI only for treatment planning. In this study, we assess the dosimetric difference between MRI- and CTbased IMRT planning for pancreatic cancer. Methods: Planning CTs and MRIs acquired for a representative pancreatic cancer patient were used. MRI-based planning utilized forced relative electron density (rED) assignment of organ specific values from IRCU report 46, where rED = 1.029 for PTV and a rED = 1.036 for non-specified tissue (NST). Six IMRT plans were generated with clinical dose-volume (DV) constraints using a research Monaco planning system employing Monte Carlo dose calculation with optional perpendicular magnetic field (MF) of 1.5T. The following five plans were generated and compared with the planning CT: 1.) CT plan with MF and dose recalculation without optimization; 2.) MRI (T2) plan with target and OARs redrawn based on MRI, forced rED, no MF, and recalculation without optimization; 3.) Similar as in 2 but with MF; 4.) MRI plan with MF but without optimization; and 5.) Similar as in 4 but with optimization. Results: Generally, noticeable differences in PTV point doses and DV parameters (DVPs) between the CT-and MRI-based plans with and without the MF were observed. These differences between the optimized plans were generally small, mostly within 2%. Larger differences were observed in point doses and mean doses for certain OARs between the CT and MRI plan, mostly due to differences between image acquisition times. Conclusion: MRI only based IMRT planning for pancreatic cancer is feasible. The differences observed between the optimized CT and MRI plans with or without the MF were practically negligible if excluding the differences between MRI and CT defined structures

MRI in patients with general paresis

International Nuclear Information System (INIS)

Zifko, U.; Wimberger, D.; Lindner, K.; Zier, G.; Grisold, W.; Schindler, E.

1996-01-01

Few cases of MRI in neurosyphilis have been reported. We examined the value of MRI in patients with general paresis; MRI was performed on four HIV-negative patients with parenchymatous neurosyphilis. It demonstrated frontal and temporal atrophy, subcortical gliosis and, in one patient, increased ferritin in the basal ganglia. The progression of the lesions on MRI correlated well with the neuropsychiatric disturbances. The MRI findings correlated with the wellknown neuropathological findings. This combination of pathological findings in neurosyphilis has not been described before and we suggest that MRI is of prognostic value in patients with general paresis. (orig.)

Whole-body bone segmentation from MRI for PET/MRI attenuation correction using shape-based averaging

DEFF Research Database (Denmark)

Arabi, Hossein; Zaidi, H.

2016-01-01

Purpose: The authors evaluate the performance of shape-based averaging (SBA) technique for whole-body bone segmentation from MRI in the context of MRI-guided attenuation correction (MRAC) in hybrid PET/MRI. To enhance the performance of the SBA scheme, the authors propose to combine it with stati......Purpose: The authors evaluate the performance of shape-based averaging (SBA) technique for whole-body bone segmentation from MRI in the context of MRI-guided attenuation correction (MRAC) in hybrid PET/MRI. To enhance the performance of the SBA scheme, the authors propose to combine...... it with statistical atlas fusion techniques. Moreover, a fast and efficient shape comparisonbased atlas selection scheme was developed and incorporated into the SBA method. Methods: Clinical studies consisting of PET/CT and MR images of 21 patients were used to assess the performance of the SBA method. In addition...... voting (MV) atlas fusion scheme was also evaluated as a conventional and commonly used method. MRI-guided attenuation maps were generated using the different segmentation methods. Thereafter, quantitative analysis of PET attenuation correction was performed using CT-based attenuation correction...

Mobius syndrome: MRI features

International Nuclear Information System (INIS)

Markarian, Maria F.; Villarroel, Gonzalo M.; Nagel, Jorge R.

2003-01-01

Purpose: Mobius Syndrome or congenital facial diplegia is associated with paralysis of the lateral gaze movements. This syndrome may include other cranial nerve palsies and be associated to musculoskeletal anomalies. Our objective is to show the MRI findings in Mobius Syndrome. Material and methods: MRI study was performed in 3 patients with clinic diagnosis of Mobius Syndrome. RMI (1.5T); exams included axial FSE (T1 and T2), FLAIR, SE/EPI, GRE/20, sagittal FSE T2 , coronal T1, diffusion, angio MRI and Spectroscopy sequences. Results: The common features of this syndrome found in MRI were: depression or straightening of the floor of the fourth ventricle, brainstem anteroposterior diameter diminution, morphologic alteration of the pons and medulla oblongata and of the hypoglossal nuclei as well as severe micrognathia. Conclusion: The morphologic alterations of Mobius Syndrome can be clearly identified by MRI; this method has proved to be a useful diagnostic examination. (author)

Head-to-toe whole-body MRI in psoriatic arthritis, axial spondyloarthritis and healthy subjects

DEFF Research Database (Denmark)

Poggenborg, René Panduro; Pedersen, Susanne Juhl; Eshed, Iris

2015-01-01

with conventional MRI (convMRI). METHODS: WBMRI (3.0-T) of patients with peripheral PsA (n = 18) or axial SpA (n = 18) and of HS (n = 12) was examined for proportion of evaluable features (readability) and the presence and pattern of lesions in axial and peripheral joints. Furthermore, global WBMRI scores...... of inflammation and structural damage were constructed, and WBMRI findings were compared with clinical measures and convMRI (SpA/HS: spine and SI joints; PsA/HS: hand). RESULTS: The readability (92-100%) and reproducibility (intrareader intraclass correlation coefficient: 0.62-1.0) were high in spine/SI joint...

Automatic segmentation of left ventricle in cardiac cine MRI images based on deep learning

Science.gov (United States)

Zhou, Tian; Icke, Ilknur; Dogdas, Belma; Parimal, Sarayu; Sampath, Smita; Forbes, Joseph; Bagchi, Ansuman; Chin, Chih-Liang; Chen, Antong

2017-02-01

In developing treatment of cardiovascular diseases, short axis cine MRI has been used as a standard technique for understanding the global structural and functional characteristics of the heart, e.g. ventricle dimensions, stroke volume and ejection fraction. To conduct an accurate assessment, heart structures need to be segmented from the cine MRI images with high precision, which could be a laborious task when performed manually. Herein a fully automatic framework is proposed for the segmentation of the left ventricle from the slices of short axis cine MRI scans of porcine subjects using a deep learning approach. For training the deep learning models, which generally requires a large set of data, a public database of human cine MRI scans is used. Experiments on the 3150 cine slices of 7 porcine subjects have shown that when comparing the automatic and manual segmentations the mean slice-wise Dice coefficient is about 0.930, the point-to-curve error is 1.07 mm, and the mean slice-wise Hausdorff distance is around 3.70 mm, which demonstrates the accuracy and robustness of the proposed inter-species translational approach.

Contrast-enhanced CT and MRI findings of atypical hepatic Echinococcus alveolarisinfestation

International Nuclear Information System (INIS)

Etlik, Oemer; Arslan, Halil; Harman, Mustafa; Temizoez, Osman; Bay, Ali; Koesem, Mustafa; Dogan, Ekrem

2005-01-01

Diagnosis of liver infestation by Echinococcus alveolaris(EA) is based on serological and radiological findings. In this report, we present a 15-year-old girl with atypical hepatic EA infestation showing central punctate calcifications and contrast enhancement on the portal and late phases of CT and MRI. CT showed a hypodense mass involving more than half of the liver with prominent central calcifications. MRI revealed hypointense signal of the infiltrative mass on both T1- and T2-weighted images. Contrast enhancement is a unique finding in hepatic EA infestation that may cause difficulties with diagnosis. MRI may provide invaluable information in the diagnosis of EA infestation of the liver, either by disclosing the infiltrative pattern of infestation without significant effect to vascular structures, or by the signal characteristics. (orig.)

Contrast-enhanced CT and MRI findings of atypical hepatic Echinococcus alveolarisinfestation

Energy Technology Data Exchange (ETDEWEB)

Etlik, Oemer; Arslan, Halil; Harman, Mustafa; Temizoez, Osman [Yuzuncu Yil University Faculty of Medicine, Department of Radiology, Van (Turkey); Bay, Ali [Yuzuncu Yil University Faculty of Medicine, Department of Paediatrics, Van (Turkey); Koesem, Mustafa [Yuzuncu Yil University Faculty of Medicine, Department of Pathology, Van (Turkey); Dogan, Ekrem [Yuzuncu Yil University Faculty of Medicine, Department of Internal Medicine, Van (Turkey)

2005-05-01

Diagnosis of liver infestation by Echinococcus alveolaris(EA) is based on serological and radiological findings. In this report, we present a 15-year-old girl with atypical hepatic EA infestation showing central punctate calcifications and contrast enhancement on the portal and late phases of CT and MRI. CT showed a hypodense mass involving more than half of the liver with prominent central calcifications. MRI revealed hypointense signal of the infiltrative mass on both T1- and T2-weighted images. Contrast enhancement is a unique finding in hepatic EA infestation that may cause difficulties with diagnosis. MRI may provide invaluable information in the diagnosis of EA infestation of the liver, either by disclosing the infiltrative pattern of infestation without significant effect to vascular structures, or by the signal characteristics. (orig.)

Research progress of BOLD-fMRI in minimal hepatic encephalopathy

International Nuclear Information System (INIS)

Zhou Zhiming; Zhao Jiannong

2013-01-01

The minimal hepatic encephalopathy is the early stage of hepatic encephalopathy. It has few apparent clinical symptoms and specific manifestations, and is difficult to diagnose. In the recent years, BOLD-fMRI has been used to study hepatic encephalopathy gradually. Through detection of the brain neuron activities in different states, it can not only locate the abnormal activity of brain functional areas, but also can find the changes of brain functional connectivity. BOLD- fMRI combining with other MR technologies can explore the pathology and pathogenesis of minimal hepatic encephalopathy from micro to macro and from structure to function. (authors)

Less Confusion in Diffusion MRI

NARCIS (Netherlands)

Tax, CMW

2016-01-01

With its unique ability to investigate tissue architecture and microstructure in vivo, diffusion MRI (dMRI) has gained tremendous interest and the society has been continuously triggered to develop novel dMRI image analysis approaches. With the overwhelming amount of strategies currently available

Portable MRI

Energy Technology Data Exchange (ETDEWEB)

Espy, Michelle A. [Los Alamos National Laboratory

2012-06-29

This project proposes to: (1) provide the power of MRI to situations where it presently isn't available; (2) perform the engineering required to move from lab to a functional prototype; and (3) leverage significant existing infrastructure and capability in ultra-low field MRI. The reasons for doing this: (1) MRI is the most powerful tool for imaging soft-tissue (e.g. brain); (2) Billions don't have access due to cost or safety issues; (3) metal will heat/move in high magnetic fields; (4) Millions of cases of traumatic brain injury in US alone; (5) even more of non-traumatic brain injury; (6) (e.g. stroke, infection, chemical exposure); (7) Need for early diagnostic; (8) 'Signature' wound of recent conflicts; (9) 22% of injuries; (10) Implications for post-traumatic stress disorder; and (11) chronic traumatic encephalopathy.

Portable MRI

International Nuclear Information System (INIS)

Espy, Michelle A.

2012-01-01

This project proposes to: (1) provide the power of MRI to situations where it presently isn't available; (2) perform the engineering required to move from lab to a functional prototype; and (3) leverage significant existing infrastructure and capability in ultra-low field MRI. The reasons for doing this: (1) MRI is the most powerful tool for imaging soft-tissue (e.g. brain); (2) Billions don't have access due to cost or safety issues; (3) metal will heat/move in high magnetic fields; (4) Millions of cases of traumatic brain injury in US alone; (5) even more of non-traumatic brain injury; (6) (e.g. stroke, infection, chemical exposure); (7) Need for early diagnostic; (8) 'Signature' wound of recent conflicts; (9) 22% of injuries; (10) Implications for post-traumatic stress disorder; and (11) chronic traumatic encephalopathy.

Predicting behavioral variant frontotemporal dementia with pattern classification in multi-center structural MRI data

Directory of Open Access Journals (Sweden)

Sebastian Meyer

2017-01-01

Conclusion: Our study demonstrates that MRI, a widespread imaging technology, can individually identify bvFTD with high accuracy in multi-center imaging data, paving the road to personalized diagnostic approaches in the future.

MRI of articular cartilaginous lesions. MRI findings in osteoarthritis of the knee joint

International Nuclear Information System (INIS)

Nozaki, Hiroyuki; Takezawa, Yuuichi; Suguro, Tohru; Igata, Atsuomi; Kudo, Yukihiko; Motegi, Mitsuo.

1995-01-01

An investigation was carried out to assess the usefulness of magnetic resonance imaging for imaging of the knee joint, especially for detecting articular cartilaginous lesions associated with osteoarthritis of the knee. A total of 141 patients with osteoarthritis were examined (23 males, 118 females). Their age range was 40-93 (mean age 66.2). Using radiotherapy examinations, patients were classified according to Hokkaido University Classification Criteria; 22, 49, 46, 16, and 8 patients were classified as Type I, II, III, IV and V, respectively. Articular cartilage defects were examined using MRI, and the number of such defects increased as the X-ray stage progressed. The appearance of a low signal intensity area in the bone marrow was examined using MRI, and the number of patients observed to have such areas increased as the x-ray stages progressed. JOA OA scores were significantly low for patients with meniscal tears. Patients were classified and results reviewed using MRI examinations. Classification by MRI of articular cartilage lesions correlated with the JOA OA scores. Low signal intensity areas in the bone marrow were frequently observed in advanced osteoarthritis cases, and there was correlation between FTA and MRI classifications of these areas. MRI is extremely valuable in detecting articular cartilage lesions in the knee joint, showing those lesions which cannot be detected by conventional radiography examinations. Thus, MRI is judged to be a clinically useful method for diagnosis of osteoarthritis. (author)

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

Science.gov (United States)

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

2012-01-01

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

Usefulness of ACR MRI phantom for quality assurance of MRI instruments

International Nuclear Information System (INIS)

Lee, Jung Whee; Ahn, Kook Jin; Lee, Seung Koo; Na, Dong Gyu; Oh, Chang Hyun; Chang, Yong Min; Lim, Tae Hwan

2006-01-01

To examine whether the ACR phantom could be used in quality standards for magnetic resonance imaging (MRI) instruments in Korea. We conducted the phantom test using the ACR MRI phantom in 20 MRI instruments currently used in Korea. According to ACR criteria, we acquired the phantom images which were then assessed by the following seven tests: geometric accuracy, high spatial resolution, slice thickness accuracy, slice position accuracy, image intensity uniformity, percent signal ghosting, and low contrast object detectability. The phantom images were interpreted by three experienced radiologists according to ACR criteria. Then, we examined the failure rate of each test and evaluated the inter-observer variation in the measurements and test failure. The failure rate of each test could be broken into the following components: geometric accuracy (11-21%), high contrast spatial resolution (10-15%), slice thickness accuracy(6-22%), slice position accuracy (5-17%), image intensity uniformity (6%), percent signal ghosting (16%), and low contrast object detectability (8-10%). In this series, all the failure rates were less than 30%. In addition, no inter-observer variation was seen in the measurements and test failure. ACR MRI phantom promises to be established as the standard phantom for MRI instruments in Korea because of its objectivity in assessing the phantom images

Total variation regularization for fMRI-based prediction of behavior

Science.gov (United States)

Michel, Vincent; Gramfort, Alexandre; Varoquaux, Gaël; Eger, Evelyn; Thirion, Bertrand

2011-01-01

While medical imaging typically provides massive amounts of data, the extraction of relevant information for predictive diagnosis remains a difficult challenge. Functional MRI (fMRI) data, that provide an indirect measure of task-related or spontaneous neuronal activity, are classically analyzed in a mass-univariate procedure yielding statistical parametric maps. This analysis framework disregards some important principles of brain organization: population coding, distributed and overlapping representations. Multivariate pattern analysis, i.e., the prediction of behavioural variables from brain activation patterns better captures this structure. To cope with the high dimensionality of the data, the learning method has to be regularized. However, the spatial structure of the image is not taken into account in standard regularization methods, so that the extracted features are often hard to interpret. More informative and interpretable results can be obtained with the ℓ1 norm of the image gradient, a.k.a. its Total Variation (TV), as regularization. We apply for the first time this method to fMRI data, and show that TV regularization is well suited to the purpose of brain mapping while being a powerful tool for brain decoding. Moreover, this article presents the first use of TV regularization for classification. PMID:21317080

MRI in ischemic heart disease

International Nuclear Information System (INIS)

Hazirolan, T.

2012-01-01

Full text: The role of magnetic resonance imaging in the evaluation of ischemic heart disease has increased over the last years. Cardiac MRI is the only imaging modality that provides 'one stop shop' assessment. Information about ventricular function, myocardial ischemia and myocardial viability can be obtained in a single cardiac MRI session. Additionally, Cardiac MRI has become a gold standard method in evaluation of myocardial viability and in assessment of ventricular mass and function. As a result, cardiac MRI enable radiologist to comprehensively assess ischemic heart disease. The aim of this presentation is to provide the reader a state-of-the art on how the newest cardiac MRI techniques can be used to study ischemic heart disease patients.

A multimodal MRI dataset of professional chess players.

Science.gov (United States)

Li, Kaiming; Jiang, Jing; Qiu, Lihua; Yang, Xun; Huang, Xiaoqi; Lui, Su; Gong, Qiyong

2015-01-01

Chess is a good model to study high-level human brain functions such as spatial cognition, memory, planning, learning and problem solving. Recent studies have demonstrated that non-invasive MRI techniques are valuable for researchers to investigate the underlying neural mechanism of playing chess. For professional chess players (e.g., chess grand masters and masters or GM/Ms), what are the structural and functional alterations due to long-term professional practice, and how these alterations relate to behavior, are largely veiled. Here, we report a multimodal MRI dataset from 29 professional Chinese chess players (most of whom are GM/Ms), and 29 age matched novices. We hope that this dataset will provide researchers with new materials to further explore high-level human brain functions.

ROLE OF MRI IN WHITE MATTER DISEASES- CLINICO-RADIOLOGICAL CORRELATION

Directory of Open Access Journals (Sweden)

Ravindranath Reddy Kamireddy

2017-11-01

Full Text Available BACKGROUND The diagnostic process is difficult as there are many different white matter disorders (inherited and acquired. MRI has high diagnostic specificity to study the pattern of brain structures. MRI is more useful in demonstrating abnormalities of myelination. MATERIALS AND METHODS Our study developed a practical algorithm that relies mainly on the characteristics of brain MRI. Our study included clinicallysuspected patients with demyelination during a period of one year. RESULTS Our study included 25 clinically-suspected patients (out of total of 400 patients with demyelination during a period of one year (February 2016 to January 2017.  Multiple sclerosis accounted for the majority of cases (36.0% followed by acute disseminated encephalomyelitis (20%.  In multiple sclerosis, majority of the patients presented in the third decade of life with a definite female preponderance (M:F-1:2.  The most common symptom and site of involvement were visual impairment (73.3% and periventricular area (80%, respectively.  Other causes like PML, PVL, CPM, reversible posterior leucoencephalopathy, leukodystrophies and motor neuron disease comprised the remainder of the cases. CONCLUSION MRI due to its excellent grey white matter resolution is very sensitive in detecting subtle demyelination, the sensitivity being still further enhanced by FLAIR sequences. MRI in correlation with the clinical signs and symptoms is an ideal modality in early diagnosis of white matter diseases.

Assessment by MRI of inflammation and damage in rheumatoid arthritis patients with methotrexate inadequate response receiving golimumab: results of the GO-FORWARD trial

DEFF Research Database (Denmark)

Conaghan, Philip G; Emery, Paul; Østergaard, Mikkel

2011-01-01

To evaluate golimumab's effect on MRI-detected inflammation and structural damage in patients with active rheumatoid arthritis (RA) despite methotrexate (MTX).......To evaluate golimumab's effect on MRI-detected inflammation and structural damage in patients with active rheumatoid arthritis (RA) despite methotrexate (MTX)....

MRI findings of vermian medulloblastoma

International Nuclear Information System (INIS)

Jung, Seung Eun; Choi, Kyu Ho; Chung, Myung Hee; Yang, Il Kwon; Shinn, Kyung Sub; Park, Young Sub

1996-01-01

To find characteristic MRI features of vermian medulloblastoma. Materials and methods; MRI studies and medical records were retrospectively reviewed for 12 patients with surgically proven midline medulloblastoma. The assessment concerned appearance of the mass in relation to surrounding structures: MR signal intensity; the enhancement pattern; the mass's location and size: presence of a cystic/necrotic area, calcification, or vascular void: extension through the foramen Luschka: degree of hydrocephalus: and presence of tonsillar herniation. The midline medulloblastoma commonly showed roundish moon-surface appearance, especially on the axial T2-weighted images. All tumors showed heterogeneous signal intensities mainly due to intratumoral cystic/necrotic or hemorrhagic changes. The tumors were commonly located at mid-and/or inferior vermis. Occasionally the tumors extended through the foramen Luschka, and caused obstructive hydrocephalus of moderate to severe degree. Post-contrast study showed heterogeneous, dense contrast enhancement in the majority of patients. The MR finding of the moon-surface appearance formed by both the mass and the intratumoral cystic/necrotic change as seen on axial T2-weighted images could be helpful in the diagnosis of vermian medulloblastoma

MRI in sarcoglycanopathies

DEFF Research Database (Denmark)

Tasca, Giorgio; Monforte, Mauro; Díaz-Manera, Jordi

2018-01-01

OBJECTIVES: To characterise the pattern and spectrum of involvement on muscle MRI in a large cohort of patients with sarcoglycanopathies, which are limb-girdle muscular dystrophies (LGMD2C-2F) caused by mutations in one of the four genes coding for muscle sarcoglycans. METHODS: Lower limb MRI sca...

Acute patellofemoral pain: aggravating activities, clinical examination, MRI and ultrasound findings

DEFF Research Database (Denmark)

Brushoj, C.; Holmich, P.; Nielsen, M.B.

2008-01-01

Objective: To investigate acute anterior knee pain caused by overuse in terms of pain location, aggravating activities, findings on clinical examination and ultrasound/MRI examination. To determine if acute anterior knee pain caused by overuse should be classified as a subgroup of patellofemoral......%)), but other synovial covered structures including the fat pad of Hoffa (12 patients (40%)), the medial plica and the joint line (12 patients (40%)) were also involved. Only eight patients (27%) experienced pain on the patellofemoral compression test. Only discrete changes was detected on MRI...

The impact of fMRI on multimodal navigation in surgery of cerebral lesions: four years clinical experience

International Nuclear Information System (INIS)

Wurm, Gabriele; Schnizer, Mathilde; Fellner, Claudia

2008-01-01

Neuronavigation with display of intraoperative structures, instrument locations, orientation and relationships to nearby structures can increase anatomic precision while enhancing the surgeon's confidence and his/her perception of safety. Combination of neuronavigation with functional imaging provides multimodal guidance for surgery of cerebral lesions. We evaluated the impact of functional MRI (fMRI) on surgical decision making and outcome. A neuronavigational device (StealthStation (tm), Medtronic Inc.) was used as platform to merge fMRI data with anatomic images, and to implement intraoperative multimodal guidance. In a 52-month period, where 977 surgical procedures were performed with the aid of neuronavigation, 88 patients underwent image-guided procedures using multimodal guidance. Patient, surgical and outcome data of this series was prospectively collected. Evaluation of 88 procedures on cerebral lesions in complex regions where fMRI data were integrated using the navigation system demonstrated that the additional information was presented in a user-friendly way. Computer assisted fMRI integration was found to be especially helpful in planning the best approach, in assessing alternative approaches, and in defining the extent of the surgical exposure. Furthermore, the surgeons found it more effective to interpret fMRI information when shown in a navigation system as compared to the traditional display on a light board or monitor. Multimodal navigation enhanced by fMRI was judged useful for optimization of surgery of cerebral lesions, especially in and around eloquent regions by experienced neurosurgeons. (orig.)

PREDICTING APHASIA TYPE FROM BRAIN DAMAGE MEASURED WITH STRUCTURAL MRI