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https://www.readbyqxmd.com/read/28532604/validation-of-dwi-pre-processing-procedures-for-reliable-differentiation-between-human-brain-gliomas
#1
Sebastian Vellmer, Aram S Tonoyan, Dieter Suter, Igor N Pronin, Ivan I Maximov
Diffusion magnetic resonance imaging (dMRI) is a powerful tool in clinical applications, in particular, in oncology screening. dMRI demonstrated its benefit and efficiency in the localisation and detection of different types of human brain tumours. Clinical dMRI data suffer from multiple artefacts such as motion and eddy-current distortions, contamination by noise, outliers etc. In order to increase the image quality of the derived diffusion scalar metrics and the accuracy of the subsequent data analysis, various pre-processing approaches are actively developed and used...
May 19, 2017: Zeitschrift Für Medizinische Physik
https://www.readbyqxmd.com/read/28511065/quantifying-the-brain-s-sheet-structure-with-normalized-convolution
#2
Chantal M W Tax, Carl-Fredrik Westin, Tom Dela Haije, Andrea Fuster, Max A Viergever, Evan Calabrese, Luc Florack, Alexander Leemans
The hypothesis that brain pathways form 2D sheet-like structures layered in 3D as "pages of a book" has been a topic of debate in the recent literature. This hypothesis was mainly supported by a qualitative evaluation of "path neighborhoods" reconstructed with diffusion MRI (dMRI) tractography. Notwithstanding the potentially important implications of the sheet structure hypothesis for our understanding of brain structure and development, it is still considered controversial by many for lack of quantitative analysis...
April 4, 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/28506703/abnormal-asymmetry-of-white-matter-tracts-between-ventral-posterior-cingulate-cortex-and-middle-temporal-gyrus-in-recent-onset-schizophrenia
#3
Sung Woo Joo, Myong-Wuk Chon, Yogesh Rathi, Martha E Shenton, Marek Kubicki, Jungsun Lee
INTRODUCTION: Previous studies have reported abnormalities in the ventral posterior cingulate cortex (vPCC) and middle temporal gyrus (MTG) in schizophrenia patients. However, it remains unclear whether the white matter tracts connecting these structures are impaired in schizophrenia. Our study investigated the integrity of these white matter tracts (vPCC-MTG tract) and their asymmetry (left versus right side) in patients with recent onset schizophrenia. METHOD: Forty-seven patients and 24 age-and sex-matched healthy controls were enrolled in this study...
May 12, 2017: Schizophrenia Research
https://www.readbyqxmd.com/read/28457975/robust-and-fast-nonlinear-optimization-of-diffusion-mri-microstructure-models
#4
R L Harms, F J Fritz, A Tobisch, R Goebel, A Roebroeck
Advances in biophysical multi-compartment modeling for diffusion MRI (dMRI) have gained popularity because of greater specificity than DTI in relating the dMRI signal to underlying cellular microstructure. A large range of these diffusion microstructure models have been developed and each of the popular models comes with its own, often different, optimization algorithm, noise model and initialization strategy to estimate its parameter maps. Since data fit, accuracy and precision is hard to verify, this creates additional challenges to comparability and generalization of results from diffusion microstructure models...
April 27, 2017: NeuroImage
https://www.readbyqxmd.com/read/28452619/comparison-of-mri-techniques-for-detecting-microadenomas-in-cushing-s-disease
#5
Yuval Grober, Hagit Grober, Max Wintermark, John A Jane, Edward H Oldfield
OBJECTIVE Many centers use conventional and dynamic contrast-enhanced MRI (DMRI) sequences in patients with Cushing's disease. The authors assessed the utility of the 3D volumetric interpolated breath-hold examination, a spoiled-gradient echo 3D T1 sequence (SGE) characterized by superior soft tissue contrast and improved resolution, compared with DMRI and conventional MRI (CMRI) for detecting microadenomas in patients with Cushing's disease. METHODS This study was a blinded assessment of pituitary MRI in patients with proven Cushing's disease...
April 28, 2017: Journal of Neurosurgery
https://www.readbyqxmd.com/read/28367515/shared-microstructural-features-of-behavioral-and-substance-addictions-revealed-in-areas-of-crossing-fibers
#6
Sarah W Yip, Kristen P Morie, Jiansong Xu, R Todd Constable, Robert T Malison, Kathleen M Carroll, Marc N Potenza
BACKGROUND: Similarities between behavioral and substance addictions exist. However, direct neurobiological comparison between addictive disorders is rare. Determination of disorder-specificity (or lack thereof) of alterations within white-matter microstructures will advance understanding of the pathophysiology of addictions. METHODS: We compared white-matter microstructural features between individuals with gambling disorder (GD; n=38), cocaine-use disorder (CUD; n=38) and healthy comparison (HC; n=38) participants, as assessed using diffusion-weighted magnetic resonance imaging (dMRI)...
March 2017: Biological Psychiatry: Cognitive Neuroscience and Neuroimaging
https://www.readbyqxmd.com/read/28275542/parkinson-s-disease-diffusion-mri-is-not-affected-by-acute-antiparkinsonian-medication
#7
Jae Woo Chung, Roxana G Burciu, Edward Ofori, Priyank Shukla, Michael S Okun, Christopher W Hess, David E Vaillancourt
OBJECTIVE: A prior longitudinal study demonstrates that free-water diffusion magnetic resonance imaging (dMRI) tracks progression in the substantia nigra (Ofori et al., 2015b). Here, we test the acute effects of antiparkinsonian medication on this established imaging progression marker for the first time. METHODS: Fifteen PD patients underwent dMRI OFF and ON-medication one day apart. ON-medication, patients were tested approximately 45 min after their usual dose of antiparkinsonian medication...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28272771/sensitivity-of-diffusion-mri-to-perilesional-reactive-astrogliosis-in-focal-ischemia
#8
Rachel A Weber, Clifford H Chan, Xingju Nie, Emily Maggioncalda, Grace Valiulis, Abigail Lauer, Edward S Hui, Jens H Jensen, DeAnna L Adkins
Reactive astrogliosis is a response to injury in the central nervous system that plays an essential role in inflammation and tissue repair. It is characterized by hypertrophy of astrocytes, alterations in astrocyte gene expression and astrocyte proliferation. Reactive astrogliosis occurs in multiple neuropathologies, including stroke, traumatic brain injury and Alzheimer's disease, and it has been proposed as a possible source of the changes in diffusion magnetic resonance imaging (dMRI) metrics observed with these diseases...
March 8, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28271301/mechanisms-of-circumferential-gyral-convolution-in-primate-brains
#9
Tuo Zhang, Mir Jalil Razavi, Hanbo Chen, Yujie Li, Xiao Li, Longchuan Li, Lei Guo, Xiaoping Hu, Tianming Liu, Xianqiao Wang
Mammalian cerebral cortices are characterized by elaborate convolutions. Radial convolutions exhibit homology across primate species and generally are easily identified in individuals of the same species. In contrast, circumferential convolutions vary across species as well as individuals of the same species. However, systematic study of circumferential convolution patterns is lacking. To address this issue, we utilized structural MRI (sMRI) and diffusion MRI (dMRI) data from primate brains. We quantified cortical thickness and circumferential convolutions on gyral banks in relation to axonal pathways and density along the gray matter/white matter boundaries...
March 7, 2017: Journal of Computational Neuroscience
https://www.readbyqxmd.com/read/28269176/multivariate-autoregressive-model-constrained-by-anatomical-connectivity-to-reconstruct-focal-sources
#10
Brahim Belaoucha, Mouloud Kachouane, Theodore Papadopoulo
In this paper, we present a framework to reconstruct spatially localized sources from Magnetoencephalography (MEG)/Electroencephalography (EEG) using spatiotemporal constraint. The source dynamics are represented by a Multivariate Autoregressive (MAR) model whose matrix elements are constrained by the anatomical connectivity obtained from diffusion Magnetic Resonance Imaging (dMRI). The framework assumes that the whole brain dynamic follows a constant MAR model in a time window of interest. The source activations and the MAR model parameters are estimated iteratively...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28269167/supervised-multimodal-fusion-and-its-application-in-searching-joint-neuromarkers-of-working-memory-deficits-in-schizophrenia
#11
Shile Qi, Vince D Calhoun, Theo G M van Erp, Eswar Damaraju, Juan Bustillo, Yuhui Du, Jessica A Turner, Daniel H Mathalon, Judith M Ford, James Voyvodic, Bryon A Mueller, Aysenil Belger, Sarah McEwen, Steven G Potkin, Adrian Preda, F Birn, Tianzi Jiang, Jing Sui
Multimodal fusion is an effective approach to better understand brain disease. To date, most current fusion approaches are unsupervised; there is need for a multivariate method that can adopt prior information to guide multimodal fusion. Here we proposed a novel supervised fusion model, called "MCCAR+jICA", which enables both identification of multimodal co-alterations and linking the covarying brain regions with a specific reference signal, e.g., cognitive scores. The proposed method has been validated on both simulated and real human brain data...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268809/automated-tracking-segmentation-and-trajectory-classification-of-pelvic-organs-on-dynamic-mri
#12
Iman Nekooeimehr, Susana Lai-Yuen, Paul Bao, Alfredo Weitzenfeld, Stuart Hart
Pelvic organ prolapse is a major health problem in women where pelvic floor organs (bladder, uterus, small bowel, and rectum) fall from their normal position and bulge into the vagina. Dynamic Magnetic Resonance Imaging (DMRI) is presently used to analyze the organs' movements from rest to maximum strain providing complementary support for diagnosis. However, there is currently no automated or quantitative approach to measure the movement of the pelvic organs and their correlation with the severity of prolapse...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268520/multi-output-gaussian-processes-for-enhancing-resolution-of-diffusion-tensor-fields
#13
Hernan Dario Vargas Cardona, Alvaro A Orozco, Mauricio A Alvarez
Second order diffusion tensor (DT) fields are widely used in several clinical applications: brain fibers connections, diagnosis of neuro-degenerative diseases, image registration, brain conductivity models, etc. However, due to current acquisition protocols and hardware limitations in MRI machines, the diffusion magnetic resonance imaging (dMRI) data is obtained with low spatial resolution (1 or 2 mm3 for each voxel). This issue can be significant, because tissue fibers are much smaller than voxel size. Interpolation has become in a successful methodology for enhancing spatial resolution of DT fields...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28266059/fractional-anisotropy-derived-from-the-diffusion-tensor-distribution-function-boosts-power-to-detect-alzheimer-s-disease-deficits
#14
Talia M Nir, Neda Jahanshad, Julio E Villalon-Reina, Dmitry Isaev, Artemis Zavaliangos-Petropulu, Liang Zhan, Alex D Leow, Clifford R Jack, Michael W Weiner, Paul M Thompson
PURPOSE: In diffusion MRI (dMRI), fractional anisotropy derived from the single-tensor model (FA(DTI) ) is the most widely used metric to characterize white matter (WM) microarchitecture, despite known limitations in regions with crossing fibers. Due to time constraints when scanning patients in clinical settings, high angular resolution diffusion imaging acquisition protocols, often used to overcome these limitations, are still rare in clinical population studies. However, the tensor distribution function (TDF) may be used to model multiple underlying fibers by representing the diffusion profile as a probabilistic mixture of tensors...
March 7, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28227406/multivariate-autoregressive-model-constrained-by-anatomical-connectivity-to-reconstruct-focal-sources
#15
Brahim Belaoucha, Mouloud Kachouane, Theodore Papadopoulo, Brahim Belaoucha, Mouloud Kachouane, Theodore Papadopoulo, Brahim Belaoucha, Theodore Papadopoulo, Mouloud Kachouane
In this paper, we present a framework to reconstruct spatially localized sources from Magnetoencephalography (MEG)/Electroencephalography (EEG) using spatiotemporal constraint. The source dynamics are represented by a Multivariate Autoregressive (MAR) model whose matrix elements are constrained by the anatomical connectivity obtained from diffusion Magnetic Resonance Imaging (dMRI). The framework assumes that the whole brain dynamic follows a constant MAR model in a time window of interest. The source activations and the MAR model parameters are estimated iteratively...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227396/supervised-multimodal-fusion-and-its-application-in-searching-joint-neuromarkers-of-working-memory-deficits-in-schizophrenia
#16
Shile Qi, Vince D Calhoun, Theo G M van Erp, Eswar Damaraju, Juan Bustillo, Yuhui Du, Jessica A Turner, Daniel H Mathalon, Judith M Ford, James Voyvodic, Bryon A Mueller, Aysenil Belger, Sarah Mc Ewen, Steven G Potkin, Adrian Preda, F Birn, Tianzi Jiang, Jing Sui, Shile Qi, Vince D Calhoun, Theo G M van Erp, Eswar Damaraju, Juan Bustillo, Yuhui Du, Jessica A Turner, Daniel H Mathalon, Judith M Ford, James Voyvodic, Bryon A Mueller, Aysenil Belger, Sarah McEwen, Steven G Potkin, Adrian Preda, F Birn, Tianzi Jiang, Jing Sui
Multimodal fusion is an effective approach to better understand brain disease. To date, most current fusion approaches are unsupervised; there is need for a multivariate method that can adopt prior information to guide multimodal fusion. Here we proposed a novel supervised fusion model, called "MCCAR+jICA", which enables both identification of multimodal co-alterations and linking the covarying brain regions with a specific reference signal, e.g., cognitive scores. The proposed method has been validated on both simulated and real human brain data...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227004/automated-tracking-segmentation-and-trajectory-classification-of-pelvic-organs-on-dynamic-mri
#17
Iman Nekooeimehr, Susana Lai-Yuen, Paul Bao, Alfredo Weitzenfeld, Stuart Hart, Iman Nekooeimehr, Susana Lai-Yuen, Paul Bao, Alfredo Weitzenfeld, Stuart Hart, Paul Bao, Susana Lai-Yuen, Stuart Hart, Alfredo Weitzenfeld, Iman Nekooeimehr
Pelvic organ prolapse is a major health problem in women where pelvic floor organs (bladder, uterus, small bowel, and rectum) fall from their normal position and bulge into the vagina. Dynamic Magnetic Resonance Imaging (DMRI) is presently used to analyze the organs' movements from rest to maximum strain providing complementary support for diagnosis. However, there is currently no automated or quantitative approach to measure the movement of the pelvic organs and their correlation with the severity of prolapse...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226694/multi-output-gaussian-processes-for-enhancing-resolution-of-diffusion-tensor-fields
#18
Hernan Dario Vargas Cardona, Alvaro A Orozco, Mauricio A Alvarez, Hernan Dario Vargas Cardona, Alvaro A Orozco, Mauricio A Alvarez, Hernan Dario Vargas Cardona, Mauricio A Alvarez, Alvaro A Orozco
Second order diffusion tensor (DT) fields are widely used in several clinical applications: brain fibers connections, diagnosis of neuro-degenerative diseases, image registration, brain conductivity models, etc. However, due to current acquisition protocols and hardware limitations in MRI machines, the diffusion magnetic resonance imaging (dMRI) data is obtained with low spatial resolution (1 or 2 mm(3) for each voxel). This issue can be significant, because tissue fibers are much smaller than voxel size. Interpolation has become in a successful methodology for enhancing spatial resolution of DT fields...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28214787/sparse-and-dense-hybrid-representation-via-subspace-modeling-for-dynamic-mri
#19
Qiegen Liu, Shanshan Wang, Dong Liang
Recent theoretical results on compressed sensing and low-rank matrix recovery have inspired significant interest in joint sparse and low rank modeling of dynamic magnetic resonance imaging (dMRI). Existing approaches usually describe these two respective prior information with different formulations. In this paper, we present a novel sparse and dense hybrid representation (SDR) model which describes the sparse plus low rank properties by a unified way. More specifically, under the learned dictionary consisting of temporal basis functions, SDR models the spatial coefficients in two subspaces with Laplacian and Gaussian prior distributions, respectively...
February 5, 2017: Computerized Medical Imaging and Graphics: the Official Journal of the Computerized Medical Imaging Society
https://www.readbyqxmd.com/read/28203748/geometric-navigation-of-axons-in-a-cerebral-pathway-comparing-dmri-with-tract-tracing-and-immunohistochemistry
#20
Farzad Mortazavi, Adrian L Oblak, Will Z Morrison, Jeremy D Schmahmann, H Eugene Stanley, Van J Wedeen, Douglas L Rosene
No abstract text is available yet for this article.
February 16, 2017: Cerebral Cortex
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