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https://www.readbyqxmd.com/read/29342192/white-matter-tract-specific-quantitative-analysis-in-multiple-sclerosis-comparison-of-optic-radiation-reconstruction-techniques
#1
Chenyu Wang, Alexander Klistorner, Linda Ly, Michael H Barnett
The posterior visual pathway is commonly affected by multiple sclerosis (MS) pathology that results in measurable clinical and electrophysiological impairment. Due to its highly structured retinotopic mapping, the visual pathway represents an ideal substrate for investigating patho-mechanisms in MS. Therefore, a reliable and robust imaging segmentation method for in-vivo delineation of the optic radiations (OR) is needed. However, diffusion-based tractography approaches, which are typically used for OR segmentation are confounded by the presence of focal white matter lesions...
2018: PloS One
https://www.readbyqxmd.com/read/29319208/image-registration-to-compensate-for-epi-distortion-in-patients-with-brain-tumors-an-evaluation-of-tract-specific-effects
#2
Angela Albi, Antonio Meola, Fan Zhang, Pegah Kahali, Laura Rigolo, Chantal M W Tax, Pelin Aksit Ciris, Walid I Essayed, Prashin Unadkat, Isaiah Norton, Yogesh Rathi, Olutayo Olubiyi, Alexandra J Golby, Lauren J O'Donnell
BACKGROUND AND PURPOSE: Diffusion magnetic resonance imaging (dMRI) provides preoperative maps of neurosurgical patients' white matter tracts, but these maps suffer from echo-planar imaging (EPI) distortions caused by magnetic field inhomogeneities. In clinical neurosurgical planning, these distortions are generally not corrected and thus contribute to the uncertainty of fiber tracking. Multiple image processing pipelines have been proposed for image-registration-based EPI distortion correction in healthy subjects...
January 10, 2018: Journal of Neuroimaging: Official Journal of the American Society of Neuroimaging
https://www.readbyqxmd.com/read/29306048/comparison-of-cumulant-expansion-and-q-space-imaging-estimates-for-diffusional-kurtosis-in-brain
#3
Vaibhav Mohanty, Emilie T McKinnon, Joseph A Helpern, Jens H Jensen
PURPOSE: To compare estimates for the diffusional kurtosis in brain as obtained from a cumulant expansion (CE) of the diffusion MRI (dMRI) signal and from q-space (QS) imaging. THEORY AND METHODS: For the CE estimates of the kurtosis, the CE was truncated to quadratic order in the b-value and fit to the dMRI signal for b-values from 0 up to 2000s/mm2. For the QS estimates, b-values ranging from 0 up to 10,000s/mm2 were used to determine the diffusion displacement probability density function (dPDF) via Stejskal's formula...
January 3, 2018: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/29279758/the-role-of-dynamic-magnetic-resonance-imaging-in-cervical-spondylotic-myelopathy
#4
REVIEW
John Paul Kolcun, Lee Onn Chieng, Karthik Madhavan, Michael Y Wang
Dynamic spinal cord compression has been investigated for several years, but until the advent of open MRI, the use of dynamic MRI (dMRI) did not gain popularity. Several publications have shown that cervical cord compression is both static and dynamic. On many occasions the evaluation of cervical spondylotic myelopathy (CSM) is straightforward, but patients are frequently encountered with a significantly worse clinical examination than would be suggested by radiological images. In this paper, we present an extensive review of the literature in order to describe the importance of dMRI in various settings and applications...
December 2017: Asian Spine Journal
https://www.readbyqxmd.com/read/29274744/analytic-tractography-a-closed-form-solution-for-estimating-local-white-matter-connectivity-with-diffusion-mri
#5
Matthew Cieslak, Tegan Brennan, Wendy Meiring, Lukas J Volz, Clint Greene, Alexander Asturias, Subhash Suri, Scott T Grafton
White matter structures composed of myelinated axons in the living human brain are primarily studied by diffusion-weighted MRI (dMRI). These long-range projections are typically characterized in a two-step process: dMRI signal is used to estimate the orientation of axon segments within each voxel, then these local orientations are linked together to estimate the spatial extent of putative white matter bundles. Tractography, the process of tracing bundles across voxels, either requires computationally expensive (probabilistic) simulations to model uncertainty in fiber orientation or ignores it completely (deterministic)...
December 21, 2017: NeuroImage
https://www.readbyqxmd.com/read/29274501/using-diffusion-mri-to-discriminate-areas-of-cortical-grey-matter
#6
Tharindu Ganepola, Zoltan Nagy, Aurobrata Ghosh, Theodore Papadopoulo, Daniel C Alexander, Martin I Sereno
Cortical area parcellation is a challenging problem that is often approached by combining structural imaging (e.g., quantitative T1, diffusion-based connectivity) with functional imaging (e.g., task activations, topological mapping, resting state correlations). Diffusion MRI (dMRI) has been widely adopted to analyse white matter microstructure, but scarcely used to distinguish grey matter regions because of the reduced anisotropy there. Nevertheless, differences in the texture of the cortical 'fabric' have long been mapped by histologists to distinguish cortical areas...
December 20, 2017: NeuroImage
https://www.readbyqxmd.com/read/29247318/super-resolution-track-density-imaging-reveals-fine-anatomical-features-in-tree-shrew-primary-visual-cortex-and-hippocampus
#7
Jian-Kun Dai, Shu-Xia Wang, Dai Shan, Hai-Chen Niu, Hao Lei
Diffusion-weighted magnetic resonance imaging (dMRI) is widely used to study white and gray matter (GM) micro-organization and structural connectivity in the brain. Super-resolution track-density imaging (TDI) is an image reconstruction method for dMRI data, which is capable of providing spatial resolution beyond the acquired data, as well as novel and meaningful anatomical contrast that cannot be obtained with conventional reconstruction methods. TDI has been used to reveal anatomical features in human and animal brains...
December 16, 2017: Neuroscience Bulletin
https://www.readbyqxmd.com/read/29234596/exploring-the-multiple-hit-hypothesis-of-preterm-white-matter-damage-using-diffusion-mri
#8
Madeleine L Barnett, Nora Tusor, Gareth Ball, Andrew Chew, Shona Falconer, Paul Aljabar, Jessica A Kimpton, Nigel Kennea, Mary Rutherford, A David Edwards, Serena J Counsell
Background: Preterm infants are at high risk of diffuse white matter injury and adverse neurodevelopmental outcome. The multiple hit hypothesis suggests that the risk of white matter injury increases with cumulative exposure to multiple perinatal risk factors. Our aim was to test this hypothesis in a large cohort of preterm infants using diffusion weighted magnetic resonance imaging (dMRI). Methods: We studied 491 infants (52% male) without focal destructive brain lesions born at < 34 weeks, who underwent structural and dMRI at a specialist Neonatal Imaging Centre...
2018: NeuroImage: Clinical
https://www.readbyqxmd.com/read/29229299/diffusion-mri-of-white-matter-microstructure-development-in-childhood-and-adolescence-methods-challenges-and-progress
#9
REVIEW
Christian K Tamnes, David R Roalf, Anne-Lise Goddings, Catherine Lebel
Diffusion magnetic resonance imaging (dMRI) continues to grow in popularity as a useful neuroimaging method to study brain development, and longitudinal studies that track the same individuals over time are emerging. Over the last decade, seminal work using dMRI has provided new insights into the development of brain white matter (WM) microstructure, connections and networks throughout childhood and adolescence. This review provides an introduction to dMRI, both diffusion tensor imaging (DTI) and other dMRI models, as well as common acquisition and analysis approaches...
December 7, 2017: Developmental Cognitive Neuroscience
https://www.readbyqxmd.com/read/29227016/patients-with-chronic-bipolar-disorder-exhibit-widespread-increases-in-extracellular-free-water
#10
Carissa Tuozzo, Amanda E Lyall, Ofer Pasternak, Anthony C D James, Timothy J Crow, Marek Kubicki
OBJECTIVES: Bipolar disorder (BP) is a debilitating psychiatric disease that is not well understood. Previous diffusion magnetic resonance imaging (dMRI) studies of BP patients found prominent microstructural white matter (WM) abnormalities of reduced fractional anisotropy (FA). Because FA is a nonspecific measure, relating these abnormalities to a specific pathology is difficult. Here, dMRI specificity was increased by free water (FW) imaging, which allows identification of changes in extracellular space (FW) from neuronal tissue (fractional anisotropy of tissue [FA-t])...
December 11, 2017: Bipolar Disorders
https://www.readbyqxmd.com/read/29204342/sex-differences-in-white-matter-alterations-following-repetitive-subconcussive-head-impacts-in-collegiate-ice-hockey-players
#11
Nico Sollmann, Paul S Echlin, Vivian Schultz, Petra V Viher, Amanda E Lyall, Yorghos Tripodis, David Kaufmann, Elisabeth Hartl, Philipp Kinzel, Lorie A Forwell, Andrew M Johnson, Elaine N Skopelja, Christian Lepage, Sylvain Bouix, Ofer Pasternak, Alexander P Lin, Martha E Shenton, Inga K Koerte
Objective: Repetitive subconcussive head impacts (RSHI) may lead to structural, functional, and metabolic alterations of the brain. While differences between males and females have already been suggested following a concussion, whether there are sex differences following exposure to RSHI remains unknown. The aim of this study was to identify and to characterize sex differences following exposure to RSHI. Methods: Twenty-five collegiate ice hockey players (14 males and 11 females, 20...
2018: NeuroImage: Clinical
https://www.readbyqxmd.com/read/29190575/dictionary-based-fiber-orientation-estimation-with-improved-spatial-consistency
#12
Chuyang Ye, Jerry L Prince
Diffusion magnetic resonance imaging (dMRI) has enabled in vivo investigation of white matter tracts. Fiber orientation (FO) estimation is a key step in tract reconstruction and has been a popular research topic in dMRI analysis. In particular, the sparsity assumption has been used in conjunction with a dictionary-based framework to achieve reliable FO estimation with a reduced number of gradient directions. Because image noise can have a deleterious effect on the accuracy of FO estimation, previous works have incorporated spatial consistency of FOs in the dictionary-based framework to improve the estimation...
November 23, 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/29149383/diffusion-mri-in-pediatric-brain-injury
#13
Emily L Dennis, Talin Babikian, Christopher C Giza, Paul M Thompson, Robert F Asarnow
Traumatic brain injury (TBI) is a major public health issue around the world and can be especially devastating in children as TBI can derail cognitive and social development. White matter (WM) is particularly vulnerable to disruption post-TBI, as myelination is ongoing during this period. Diffusion magnetic resonance imaging (dMRI) is a versatile modality for identifying and quantifying WM disruption and can detect diffuse axonal injury (DAI or TAI (traumatic axonal injury)). This review covers dMRI studies of pediatric TBI, including mild to severe injuries, and covering all periods post-injury...
October 2017: Child's Nervous System: ChNS: Official Journal of the International Society for Pediatric Neurosurgery
https://www.readbyqxmd.com/read/29126955/white-matter-changes-correlates-of-peripheral-neuroinflammation-in-patients-with-parkinson-s-disease
#14
Maryam Haghashomar, Farzaneh Rahmani, Mohammad Hadi Aarabi, Shima Shahjouei, Soheila Sobhnai, Maryam Rahmani
Neuroinflammatory pathology has long been identified to contribute to the pathology of Parkinson disease. Early microstructural changes in white matter tracts might give a clue for earlier detection of PD. We investigated through diffusion MRI connectometry the structural correlates of white matter tracts of 81 patients with PD with whole blood neutrophil to lymphocyte ratio (NLR), controlling for age and sex. Diffusion data were reconstructed in the MNI space using q-space diffeomorphic reconstruction to obtain the spin distribution function...
November 7, 2017: Neuroscience
https://www.readbyqxmd.com/read/29120867/quantifying-the-ultrastructure-of-carotid-arteries-using-high-resolution-micro-diffusion-tensor-imaging-comparison-of-intact-versus-open-cut-tissue
#15
Syed Salman Shahid, Robert T Gaul, Christian Kerskens, Vittoria Flamini, Caitríona Lally
Diffusion magnetic resonance imaging (dMRI) can provide insights into the microstructure of intact arterial tissue. The current study employed high magnetic field MRI to obtain ultra-high resolution dMRI at an isotropic voxel resolution of 117 µm(3) in less than 2 h of scan time. A parameter selective single shell (128 directions) diffusion-encoding scheme based on Stejskel-Tanner sequence with echo-planar imaging (EPI) readout was used. EPI segmentation was used to reduce the echo time (TE) and to minimise the susceptibility-induced artefacts...
November 9, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29093806/low-rank-and-sparse-decomposition-model-for-accelerating-dynamic-mri-reconstruction
#16
Junbo Chen, Shouyin Liu, Min Huang
The reconstruction of dynamic magnetic resonance imaging (dMRI) from partially sampled k-space data has to deal with a trade-off between the spatial resolution and temporal resolution. In this paper, a low-rank and sparse decomposition model is introduced to resolve this issue, which is formulated as an inverse problem regularized by robust principal component analysis (RPCA). The inverse problem can be solved by convex optimization method. We propose a scalable and fast algorithm based on the inexact augmented Lagrange multipliers (IALM) to carry out the convex optimization...
2017: Journal of Healthcare Engineering
https://www.readbyqxmd.com/read/29092950/slicerdmri-open-source-diffusion-mri-software-for-brain-cancer-research
#17
Isaiah Norton, Walid Ibn Essayed, Fan Zhang, Sonia Pujol, Alex Yarmarkovich, Alexandra J Golby, Gordon Kindlmann, Demian Wasserman, Raul San Jose Estepar, Yogesh Rathi, Steve Pieper, Ron Kikinis, Hans J Johnson, Carl-Fredrik Westin, Lauren J O'Donnell
Diffusion MRI (dMRI) is the only noninvasive method for mapping white matter connections in the brain. We describe SlicerDMRI, a software suite that enables visualization and analysis of dMRI for neuroscientific studies and patient-specific anatomic assessment. SlicerDMRI has been successfully applied in multiple studies of the human brain in health and disease, and here, we especially focus on its cancer research applications. As an extension module of the 3D Slicer medical image computing platform, the SlicerDMRI suite enables dMRI analysis in a clinically relevant multimodal imaging workflow...
November 1, 2017: Cancer Research
https://www.readbyqxmd.com/read/29075681/subject-specific-structural-parcellations-based-on-randomized-ab-divergences
#18
Nicolas Honnorat, Drew Parker, Birkan Tunç, Christos Davatzikos, Ragini Verma
Brain parcellation provides a means to approach the brain in smaller regions. It also affords an appropriate dimensionality reduction in the creation of connectomes. Most approaches to creating connectomes start with registering individual scans to a template, which is then parcellated. Data processing usually ends with the projection of individual scans onto the parcellation for extracting individual biomarkers, such as connectivity signatures. During this process, registration errors can significantly alter the quality of biomarkers...
September 2017: Medical Image Computing and Computer-assisted Intervention: MICCAI ..
https://www.readbyqxmd.com/read/29074279/histological-validation-of-diffusion-mri-fiber-orientation-distributions-and-dispersion
#19
Kurt G Schilling, Vaibhav Janve, Yurui Gao, Iwona Stepniewska, Bennett A Landman, Adam W Anderson
Diffusion magnetic resonance imaging (dMRI) is widely used to probe tissue microstructure, and is currently the only non-invasive way to measure the brain's fiber architecture. While a large number of approaches to recover the intra-voxel fiber structure have been utilized in the scientific community, a direct, 3D, quantitative validation of these methods against relevant histological fiber geometries is lacking. In this study, we investigate how well different high angular resolution diffusion imaging (HARDI) models and reconstruction methods predict the ground-truth histologically defined fiber orientation distribution (FOD), as well as investigate their behavior over a range of physical and experimental conditions...
October 23, 2017: NeuroImage
https://www.readbyqxmd.com/read/29060679/spatial-regularization-based-on-dmri-to-solve-eeg-meg-inverse-problem
#20
Brahim Belaoucha, Theodore Papadopoulo
In this paper, we present a new approach to reconstruct dipole magnitudes of a distributed source model for magnetoencephalographic (MEG) and electroencephalographic (EEG). This approach is based on the structural homogeneity of the cortical regions which are obtained using diffusion MRI (dMRI). First, we parcellate the cortical surface into functional regions using structural information. Then, we use a weighting matrix that relates the dipoles' magnitudes of sources inside these functional regions. The weights are based on the region's structural homogeneity...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
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