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https://www.readbyqxmd.com/read/28214787/sparse-and-dense-hybrid-representation-via-subspace-modeling-for-dynamic-mri
#1
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
#2
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
https://www.readbyqxmd.com/read/28180075/independent-value-added-by-diffusion-mri-for-prediction-of-cognitive-function-in-older-adults
#3
Julia A Scott, Duygu Tosun, Meredith N Braskie, Pauline Maillard, Paul M Thompson, Michael Weiner, Charles DeCarli, Owen T Carmichael
The purpose of this study was to determine whether white matter microstructure measured by diffusion magnetic resonance imaging (dMRI) provides independent information about baseline level or change in executive function (EF) or memory (MEM) in older adults with and without cognitive impairment. Longitudinal data was acquired from the Alzheimer's Disease Neuroimaging Initiative (ADNI) study from phases GO and 2 (2009-2015). ADNI participants included were diagnosed as cognitively normal (n = 46), early mild cognitive impairment (MCI) (n = 48), late MCI (n = 29), and dementia (n = 39) at baseline...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28176263/multi-site-harmonization-of-diffusion-mri-data-in-a-registration-framework
#4
Hengameh Mirzaalian, Lipeng Ning, Peter Savadjiev, Ofer Pasternak, Sylvain Bouix, Oleg Michailovich, Sarina Karmacharya, Gerald Grant, Christine E Marx, Rajendra A Morey, Laura A Flashman, Mark S George, Thomas W McAllister, Norberto Andaluz, Lori Shutter, Raul Coimbra, Ross D Zafonte, Mike J Coleman, Marek Kubicki, Carl-Fredrik Westin, Murray B Stein, Martha E Shenton, Yogesh Rathi
Diffusion MRI (dMRI) data acquired on different scanners varies significantly in its content throughout the brain even if the acquisition parameters are nearly identical. Thus, proper harmonization of such data sets is necessary to increase the sample size and thereby the statistical power of neuroimaging studies. In this paper, we present a novel approach to harmonize dMRI data (the raw signal, instead of dMRI derived measures such as fractional anisotropy) using rotation invariant spherical harmonic (RISH) features embedded within a multi-modal image registration framework...
February 7, 2017: Brain Imaging and Behavior
https://www.readbyqxmd.com/read/28092972/tracking-dynamic-interactions-between-structural-and-functional-connectivity-a-tms-eeg-dmri-study
#5
Enrico Amico, Olivier Bodart, Mario Rosanova, Olivia Gosseries, Lizette Heine, Pieter Van Mierlo, Charlotte Martial, Marcello Massimini, Daniele Marinazzo, Steven Laureys
Transcranial magnetic stimulation (TMS) in combination with neuroimaging techniques allows to measure the effects of a direct perturbation of the brain. When coupled to high density electroencephalography (TMS/hd-EEG), TMS pulses revealed electrophysiological signatures of different cortical modules in health and disease. However, the neural underpinnings of these signatures remain unclear. Here, by applying multimodal analyses of cortical response to TMS recordings and diffusion magnetic resonance imaging (dMRI) tractography, we investigated the relationship between functional and structural features of different cortical modules in a cohort of awake healthy volunteers...
January 16, 2017: Brain Connectivity
https://www.readbyqxmd.com/read/28072384/impact-of-cerebellar-atrophy-on-cortical-gray-matter-and-cerebellar-peduncles-as-assessed-by-voxel-based-morphometry-and-high-angular-resolution-diffusion-imaging
#6
Michael Dayan, G Olivito, M Molinari, Mara Cercignani, Marco Bozzali, M Leggio
In recent years the cerebellum has been attributed amore important role in higher-level functions than previously believed. We examined a cohort of patients suffering from cerebellar atrophy resulting in ataxia, with two main objectives: first to investigate which regions of the cerebrum were affected by the cerebellar degeneration, and second to assess whether diffusion magnetic resonance imaging (dMRI) metrics within the medial (MCP) and superior cerebellar peduncle (SCP) - namely fractional anisotropy (FA) and radial diffusivity (RD) - could be used as a biomarker in patients with this condition...
October 2016: Functional Neurology
https://www.readbyqxmd.com/read/27994537/alignment-of-tractograms-as-graph-matching
#7
Emanuele Olivetti, Nusrat Sharmin, Paolo Avesani
The white matter pathways of the brain can be reconstructed as 3D polylines, called streamlines, through the analysis of diffusion magnetic resonance imaging (dMRI) data. The whole set of streamlines is called tractogram and represents the structural connectome of the brain. In multiple applications, like group-analysis, segmentation, or atlasing, tractograms of different subjects need to be aligned. Typically, this is done with registration methods, that transform the tractograms in order to increase their similarity...
2016: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/27982056/microstructure-imaging-of-crossing-mix-white-matter-fibers-from-diffusion-mri
#8
Hamza Farooq, Junqian Xu, Jung Who Nam, Daniel F Keefe, Essa Yacoub, Tryphon Georgiou, Christophe Lenglet
Diffusion MRI (dMRI) reveals microstructural features of the brain white matter by quantifying the anisotropic diffusion of water molecules within axonal bundles. Yet, identifying features such as axonal orientation dispersion, density, diameter, etc., in complex white matter fiber configurations (e.g. crossings) has proved challenging. Besides optimized data acquisition and advanced biophysical models, computational procedures to fit such models to the data are critical. However, these procedures have been largely overlooked by the dMRI microstructure community and new, more versatile, approaches are needed to solve complex biophysical model fitting problems...
December 16, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27903438/neurite-density-imaging-versus-imaging-of-microscopic-anisotropy-in-diffusion-mri-a-model-comparison-using-spherical-tensor-encoding
#9
Björn Lampinen, Filip Szczepankiewicz, Johan Mårtensson, Danielle van Westen, Pia C Sundgren, Markus Nilsson
In diffusion MRI (dMRI), microscopic diffusion anisotropy can be obscured by orientation dispersion. Separation of these properties is of high importance, since it could allow dMRI to non-invasively probe elongated structures such as neurites (axons and dendrites). However, conventional dMRI, based on single diffusion encoding (SDE), entangles microscopic anisotropy and orientation dispersion with intra-voxel variance in isotropic diffusivity. SDE-based methods for estimating microscopic anisotropy, such as the neurite orientation dispersion and density imaging (NODDI) method, must thus rely on model assumptions to disentangle these features...
February 15, 2017: NeuroImage
https://www.readbyqxmd.com/read/27853964/brain-pathway-differences-between-parkinson-s-disease-patients-with-and-without-rem-sleep-behavior-disorder
#10
Mina Ansari, Farzaneh Rahmani, Mahsa Dolatshahi, Atefe Pooyan, Mohammad Hadi Aarabi
PURPOSE: REM (rapid eye movement) sleep behavior disorder (RBD) is characterized by increased muscle tone and violent limb movements and is a usual symptom of the early stages of Parkinson's disease (PD). PD patients with RBD represent faster motor and cognitive dysfunction progression. However, there are limited studies on possible structural brain changes underpinning this disorder. METHODS: Diffusion magnetic resonance imaging (DMRI) was used to assess whether microstructural abnormalities in the brain of 23 RBD positive PD are detectable compared to 31 RBD negative PD...
November 16, 2016: Sleep & Breathing, Schlaf & Atmung
https://www.readbyqxmd.com/read/27815462/early-non-invasive-detection-of-acute-1-2-dichloroethane-induced-toxic-encephalopathy-in-rats
#11
Xiaoliang Zhou, Yuze Cao, Christoph Leuze, Binbin Nie, Baoci Shan, Wenbin Zhou, Peter Cipriano, B O Xiao
AIM: To assess the acute effect of 1,2-dichloroethane (1,2-DCE) on rat brain using diffusion magnetic resonance imaging (dMRI). MATERIALS AND METHODS: We performed dMRI on 30 male Sprague-Dawley rats, microstructural alterations were investigated by calculating the mean fractional anisotropy (FA) and apparent diffusion coefficient (ADC) changes in eight selected brain regions of interest. For the whole brain, clusters of 20+ voxels that differed significantly in FA and ADC between groups were marked...
November 2016: In Vivo
https://www.readbyqxmd.com/read/27790095/merged-group-tractography-evaluation-with-selective-automated-group-integrated-tractography
#12
David Q Chen, Jidan Zhong, David J Hayes, Brendan Behan, Matthew Walker, Peter S-P Hung, Mojgan Hodaie
Introduction: Tractography analysis in group-based studies across large populations has been difficult to implement. We propose Selective Automated Group Integrated Tractography (SAGIT), an automated group tractography software platform that incorporates multiple diffusion magnetic resonance imaging (dMRI) practices which will allow great accessibility to group-wise dMRI. We use a merged tractography approach that permits evaluation of tractography datasets at the group level. We also introduce an image normalized overlap score (NOS) that measures the quality of the group tractography results...
2016: Frontiers in Neuroanatomy
https://www.readbyqxmd.com/read/27781971/impact-of-cerebellar-atrophy-on-cortical-gray-matter-and-cerebellar-peduncles-as-assessed-by-voxel-based-morphometry-and-high-angular-resolution-diffusion-imaging
#13
Michael Dayan, G Olivito, M Molinari, Mara Cercignani, Marco Bozzali, M Leggio
In recent years the cerebellum has been attributed amore important role in higher-level functions than previously believed. We examined a cohort of patients suffering from cerebellar atrophy resulting in ataxia, with two main objectives: first to investigate which regions of the cerebrum were affected by the cerebellar degeneration, and second to assess whether diffusion magnetic resonance imaging (dMRI) metrics within the medial (MCP) and superior cerebellar peduncle (SCP) - namely fractional anisotropy (FA) and radial diffusivity (RD) - could be used as a biomarker in patients with this condition...
October 26, 2016: Functional Neurology
https://www.readbyqxmd.com/read/27751940/precise-inference-and-characterization-of-structural-organization-picaso-of-tissue-from-molecular-diffusion
#14
Lipeng Ning, Evren Özarslan, Carl-Fredrik Westin, Yogesh Rathi
Inferring the microstructure of complex media from the diffusive motion of molecules is a challenging problem in diffusion physics. In this paper, we introduce a novel representation of diffusion MRI (dMRI) signal from tissue with spatially-varying diffusivity using a diffusion disturbance function. This disturbance function contains information about the (intra-voxel) spatial fluctuations in diffusivity due to restrictions, hindrances and tissue heterogeneity of the underlying tissue substrate. We derive the short- and long-range disturbance coefficients from this disturbance function to characterize the tissue structure and organization...
October 14, 2016: NeuroImage
https://www.readbyqxmd.com/read/27749493/impact-of-sleep-restriction-on-the-structural-brain-network
#15
Min-Hee Lee, Youngjin Lee, Yoon Ho Hwang, Areum Min, Bong Soo Han, Dong Youn Kim
Sleep restriction (SR) is defined as the condition of not having enough sleep, and it can cause brain injury. In this study, we examined the impact of SR on the structural brain network. We obtained diffusion MRI (dMRI) data for the SR group of fourteen participants who got less than or equal to 5.5 h of sleep for the last 1 month and normal group of the same number of participants who got 7 h of sleep. We constructed the structural brain networks from the dMRI data and analyzed them using graph theoretical approaches...
September 30, 2016: Neuroreport
https://www.readbyqxmd.com/read/27731906/fast-diffusion-kurtosis-imaging-of-fibrotic-mouse-kidneys
#16
B F Kjølby, A R Khan, A Chuhutin, L Pedersen, J B Jensen, S Jakobsen, D Zeidler, R Sangill, J R Nyengaard, S N Jespersen, B Hansen
Diffusion kurtosis imaging (DKI) is sensitive to tissue microstructure and may therefore be useful in the diagnosis and monitoring of disease in brain and body organs. Generally, diffusion magnetic resonance imaging (dMRI) in the body is challenging because of the heterogeneous body composition, which can cause image artefacts as a result of chemical shifts and susceptibility differences. In addition, the abdomen possesses physiological factors (e.g. breathing, heartbeat, blood flow) which may severely reduce image quality, especially when echo planar imaging is employed, as is typical in dMRI...
December 2016: NMR in Biomedicine
https://www.readbyqxmd.com/read/27730479/abnormalities-in-brain-white-matter-in-adolescents-with-22q11-2-deletion-syndrome-and-psychotic-symptoms
#17
Zora Kikinis, Kang Ik K Cho, Ioana L Coman, Petya D Radoeva, Sylvain Bouix, Yingying Tang, Ryan Eckbo, Nikos Makris, Jun Soo Kwon, Marek Kubicki, Kevin M Antshel, Wanda Fremont, Martha E Shenton, Wendy R Kates
BACKGROUND: 22q11.2 Deletion Syndrome (22q11DS) is considered to be a promising cohort to explore biomarkers of schizophrenia risk based on a 30 % probability of developing schizophrenia in adulthood. In this study, we investigated abnormalities in the microstructure of white matter in adolescents with 22q11DS and their specificity to prodromal symptoms of schizophrenia. METHODS: Diffusion Magnetic Resonance Imaging (dMRI) data were acquired from 50 subjects with 22q11DS (9 with and 41 without prodromal psychotic symptoms), and 47 matched healthy controls (mean age 18 +/-2 years)...
October 11, 2016: Brain Imaging and Behavior
https://www.readbyqxmd.com/read/27722821/fast-automatic-segmentation-of-white-matter-streamlines-based-on-a-multi-subject-bundle-atlas
#18
Nicole Labra, Pamela Guevara, Delphine Duclap, Josselin Houenou, Cyril Poupon, Jean-François Mangin, Miguel Figueroa
This paper presents an algorithm for fast segmentation of white matter bundles from massive dMRI tractography datasets using a multisubject atlas. We use a distance metric to compare streamlines in a subject dataset to labeled centroids in the atlas, and label them using a per-bundle configurable threshold. In order to reduce segmentation time, the algorithm first preprocesses the data using a simplified distance metric to rapidly discard candidate streamlines in multiple stages, while guaranteeing that no false negatives are produced...
January 2017: Neuroinformatics
https://www.readbyqxmd.com/read/27721932/application-of-a-novel-quantitative-tractography-based-analysis-of-diffusion-tensor-imaging-to-examine-fiber-bundle-length-in-human-cerebral-white-matter
#19
Laurie M Baker, Ryan P Cabeen, Sarah Cooley, David H Laidlaw, Robert H Paul
This paper reviews basic methods and recent applications of length-based fiber bundle analysis of cerebral white matter using diffusion magnetic resonance imaging (dMRI). Diffusion weighted imaging (DWI) is a dMRI technique that uses the random motion of water to probe tissue microstructure in the brain. Diffusion tensor imaging (DTI) is an extension of DWI that measures the magnitude and direction of water diffusion in cerebral white matter, using either voxel-based scalar metrics or tractography-based analyses...
April 2016: Technology and Innovation
https://www.readbyqxmd.com/read/27686222/processing-time-reduction-an-application-in-living-human-high-resolution-diffusion-magnetic-resonance-imaging-data
#20
Nicolás F Lori, Augustin Ibañez, Rui Lavrador, Lucia Fonseca, Carlos Santos, Rui Travasso, Artur Pereira, Rosaldo Rossetti, Nuno Sousa, Victor Alves
High Angular Resolution Diffusion Imaging (HARDI) is a type of brain imaging that collects a very large amount of data, and if many subjects are considered then it amounts to a big data framework (e.g., the human connectome project has 20 Terabytes of data). HARDI is also becoming increasingly relevant for clinical settings (e.g., detecting early cerebral ischemic changes in acute stroke, and in pre-clinical assessment of white matter-WM anatomy using tractography). Thus, this method is becoming a routine assessment in clinical settings...
November 2016: Journal of Medical Systems
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