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Diffusion tensor

Nicola Moscufo, Dorothy B Wakefield, Dominik S Meier, Michele Cavallari, Charles R G Guttmann, William B White, Leslie Wolfson
Mobility impairment in older persons is associated with brain white matter hyperintensities (WMH), a common finding in magnetic resonance images and one established imaging biomarker of small vessel disease. The contribution of possible microstructural abnormalities within normal-appearing white matter (NAWM) to mobility, however, remains unclear. We used diffusion tensor imaging (DTI) measures, i.e. fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), to assess microstructural changes within supratentorial NAWM and WMH sub-compartments, and to investigate their association with changes in mobility performance, i...
2018: PloS One
Kalliopi Pitarokoili, Moritz Kronlage, Philip Bäumer, Daniel Schwarz, Ralf Gold, Martin Bendszus, Min-Suk Yoon
Background: We present a clinical, electrophysiological, sonographical and magnetic resonance neurography (MRN) study examining the complementary role of two neuroimaging methods of the peripheral nervous system for patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Furthermore, we explore the significance of cross-sectional area (CSA) increase through correlations with MRN markers of nerve integrity. Methods: A total of 108 nerve segments on the median, ulnar, radial, tibial and fibular nerve, as well as the lumbar and cervical plexus of 18 CIDP patients were examined with high-resonance nerve ultrasound (HRUS) and MRN additionally to the nerve conduction studies...
2018: Therapeutic Advances in Neurological Disorders
Ashley J Robinson, M Ashraf Ederies
This paper is based on a literature review from 2011 to 2016. The paper is divided into two main sections. The first section relates to technical advances in fetal imaging techniques, including fetal motion compensation, imaging at 3.0 T, 3-D T2-weighted MRI, susceptibility-weighted imaging, computed tomography, morphometric analysis, diffusion tensor imaging, spectroscopy and fetal behavioral assessment. The second section relates to clinical updates, including cerebral lamination, migrational anomalies, midline anomalies, neural tube defects, posterior fossa anomalies, sulcation/gyration and hypoxic-ischemic insults...
April 2018: Pediatric Radiology
Jae W Song, Gerlinde M Gruber, Janina M Patsch, Rainer Seidl, Daniela Prayer, Gregor Kasprian
Prenatal detection of abnormal white matter tracts might serve as a structural marker for altered neurodevelopment. As a result of many technical and patient-related challenges, the accuracy of prenatal tractography remains unknown. We hypothesized that characteristics of prenatal tractography of the corpus callosum and corticospinal tracts derived from fetal diffusion tensor imaging (DTI) data are accurate and predictive of the integrity of these tracts postnatally. We compared callosal and corticospinal tracts of 12 subjects with paired prenatal (age: 23-35 gestational weeks) and postnatal (age: 1 day to 2 years) DTI examinations (b values of 0 s/mm2 and 700 s/mm2 , 16 gradient encoding directions) using deterministic tractography...
April 2018: Pediatric Radiology
Asaff Harel, Dylan Sperling, Maria Petracca, Achillefs Ntranos, Ilana Katz-Sand, Stephen Krieger, Fred Lublin, Zichen Wang, Yangbo Liu, Matilde Inglese
OBJECTIVES: The accuracy of 'no evidence of disease activity' (NEDA) in predicting long-term clinical outcome in patients with relapsing remitting multiple sclerosis (RRMS) is unproven, and there is growing evidence that NEDA does not rule out disease worsening. We used diffusion tensor imaging (DTI) to investigate whether ongoing brain microstructural injury occurs in patients with RRMS meeting NEDA criteria. METHODS: We performed a retrospective study to identify patients with RRMS visiting our centre over a 3-month period who had undergone prior longitudinal DTI evaluation at our facility spanning ≥2 years...
March 16, 2018: Journal of Neurology, Neurosurgery, and Psychiatry
Rami Darwazeh, Miao Wei, Jianjun Zhong, Zhaosi Zhang, Fajin Lv, Mazhar Darwazeh, Yi Guo, Yi Yan, Samer S Hoz, Xiaochuan Sun
OBJECTIVE: Little is known about the pathophysiological mechanisms of white matter injury after aneurysmal subarachnoid hemorrhage (aSAH). The purpose of this study is to investigate whether mammillothalamic tract (MTT) or corticospinal tract (CST) is more affected by aSAH in the same patients with good-outcome (Grade 5 on Glasgow Outcome Scale (GOS) at 3 months) using diffusion tensor imaging (DTI). METHODS: Between June 2013 to September 2016, 21 good-outcome patients with aSAH and 21 sex-and age-matched normal healthy control participants were recruited...
March 13, 2018: World Neurosurgery
N Sato, Z Yoshida
Topological constraints on a dynamical system often manifest themselves as breaking of the Hamiltonian structure; well-known examples are nonholonomic constraints on Lagrangian mechanics. The statistical mechanics under such topological constraints is the subject of this study. Conventional arguments based on phase spaces, Jacobi identity, invariant measure, or the H theorem are no longer applicable since all these notions stem from the symplectic geometry underlying canonical Hamiltonian systems. Remembering that Hamiltonian systems are endowed with field tensors (canonical 2-forms) that have zero helicity, our mission is to extend the scope toward the class of systems governed by finite-helicity field tensors...
February 2018: Physical Review. E
M Reeks, D C Swailes, A D Bragg
This paper is about the kinetic equation for gas-particle flows, in particular its well-posedness and realizability and its relationship to the generalized Langevin model (GLM) probability density function (PDF) equation. Previous analyses, e.g. [J.-P. Minier and C. Profeta, Phys. Rev. E 92, 053020 (2015)PLEEE81539-375510.1103/PhysRevE.92.053020], have concluded that this kinetic equation is ill posed, that in particular it has the properties of a backward heat equation, and as a consequence, its solution will in the course of time exhibit finite-time singularities...
February 2018: Physical Review. E
Da Li, Yu-Ming Jiao, Liang Wang, Fu-Xin Lin, Jun Wu, Xian-Zeng Tong, Shuo Wang, Yong Cao
OBJECTIVE Surgical management of brainstem lesions is challenging due to the highly compact, eloquent anatomy of the brainstem. This study aimed to evaluate the safety and efficacy of preoperative diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) in brainstem cavernous malformations (CMs). METHODS A prospective randomized controlled clinical trial was performed by using stratified blocked randomization. The primary eligibility criterion of the study was being a surgical candidate for brainstem CMs (with informed consent)...
March 16, 2018: Journal of Neurosurgery
Xiao-Ling Yang, Yolandi van der Merwe, Jeffrey Sims, Carlos Parra, Leon C Ho, Joel S Schuman, Gadi Wollstein, Kira L Lathrop, Kevin C Chan
Although elevated intraocular pressure (IOP) and age are major risk factors for glaucoma, their effects on glaucoma pathogenesis remain unclear. This study examined the onset and progression of glaucomatous changes to ocular anatomy and physiology, structural and physiological brain integrity, and visuomotor behavior in the DBA/2J mice via non-invasive tonometry, multi-parametric magnetic resonance imaging (MRI) and optokinetic assessments from 5 to 12 months of age. Using T2-weighted MRI, diffusion tensor MRI, and manganese-enhanced MRI, increasing IOP elevation at 9 and 12 months old coincided with anterior chamber deepening, altered fractional anisotropy and radial diffusivity of the optic nerve and optic tract, as well as reduced anterograde manganese transport along the visual pathway respectively in the DBA/2J mice...
March 15, 2018: Scientific Reports
Heather T Whittaker, Shenghua Zhu, Domenico L Di Curzio, Richard Buist, Xin-Min Li, Suzanna Noy, Frances K Wiseman, Jonathan D Thiessen, Melanie Martin
Alzheimer's disease (AD) pathology causes microstructural changes in the brain. These changes, if quantified with magnetic resonance imaging (MRI), could be studied for use as an early biomarker for AD. The aim of our study was to determine if T1 relaxation, diffusion tensor imaging (DTI), and quantitative magnetization transfer imaging (qMTI) metrics could reveal changes within the hippocampus and surrounding white matter structures in ex vivo transgenic mouse brains overexpressing human amyloid precursor protein with the Swedish mutation...
March 12, 2018: Magnetic Resonance Imaging
Esther M C van Leijsen, H Bea Kuiperij, Iris Kersten, Mayra I Bergkamp, Ingeborg W M van Uden, Hugo Vanderstichele, Erik Stoops, Jurgen A H R Claassen, Ewoud J van Dijk, Frank-Erik de Leeuw, Marcel M Verbeek
BACKGROUND AND PURPOSE: Cerebral small vessel disease (SVD) is a frequent pathology in aging and contributor to the development of dementia. Plasma Aβ (amyloid β) levels may be useful as early biomarker, but the role of plasma Aβ in SVD remains to be elucidated. We investigated the association of plasma Aβ levels with severity and progression of SVD markers. METHODS: We studied 487 participants from the RUN DMC study (Radboud University Nijmegen Diffusion Tensor and Magnetic Resonance Imaging Cohort) of whom 258 participants underwent 3 MRI assessments during 9 years...
March 14, 2018: Stroke; a Journal of Cerebral Circulation
G Oriolo, E Egmond, Z Mariño, M Cavero, R Navines, L Zamarrenho, R Solà, J Pujol, N Bargallo, X Forns, R Martin-Santos
BACKGROUND: Chronic hepatitis C is considered a systemic disease because of extra-hepatic manifestations. Neuroimaging has been employed in hepatitis C virus-infected patients to find in vivo evidence of central nervous system alterations. AIMS: Systematic review and meta-analysis of neuroimaging research in chronic hepatitis C treatment naive patients, or patients previously treated without sustained viral response, to study structural and functional brain impact of hepatitis C...
March 14, 2018: Alimentary Pharmacology & Therapeutics
Pawel J Winklewski, Agnieszka Sabisz, Patrycja Naumczyk, Krzysztof Jodzio, Edyta Szurowska, Arkadiusz Szarmach
The use of the diffusion tensor imaging (DTI) is rapidly growing in the neuroimaging field. Nevertheless, rigorously performed quantitative validation of DTI pathologic metrics remains very limited owing to the difficulty in co-registering quantitative histology findings with magnetic resonance imaging. The aim of this review is to summarize the existing state-of-the-art knowledge with respect to axial (λ║ ) and radial (λ┴ ) diffusivity as DTI markers of axonal and myelin damage, respectively. First, we provide technical background for DTI and briefly discuss the specific organization of white matter in bundles of axonal fibers running in parallel; this is the natural target for imaging based on diffusion anisotropy...
2018: Frontiers in Neurology
Evan P Pasha, Alex C Birdsill, Stephanie Oleson, Hirofumi Tanaka, Andreana P Haley
Sex differences in cerebral white matter (WM) aging have been debated extensively over the past 2 decades without unequivocal resolution. We aimed to determine if the effects of age and arterial stiffness on WM microstructure differ between sexes. Artery elasticity via carotid artery compliance (CAC) and WM diffusion metrics via diffusion tensor image-derived fractional anisotropy (FA) and mean diffusivity (MD) were measured in 155 (87 females) middle-aged (40-62 years) adults. Males demonstrated poorer water diffusion metrics in WM than women in the corpus callosum body, cingulum, and cingulum (hippocampal)...
February 17, 2018: Neurobiology of Aging
Vishwesh Nath, Kurt G Schilling, Prasanna Parvathaneni, Justin Blaber, Allison E Hainline, Zhaohua Ding, Adam Anderson, Bennett A Landman
The diffusion tensor model is nonspecific in regions where micrometer structural patterns are inconsistent at the millimeter scale (i.e., brain regions with pathways that cross, bend, branch, fan, etc.). Numerous models have been proposed to represent crossing fibers and complex intravoxel structure from in vivo diffusion weighted magnetic resonance imaging (e.g., high angular resolution diffusion imaging-HARDI). Here, we present an empirical comparison of two HARDI approaches-persistent angular structure MRI (PAS-MRI) and Q-ball-using a newly acquired reproducibility dataset...
January 2018: Journal of Medical Imaging
Panlong Li, Han Shan, Shengxiang Liang, Binbin Nie, Shaofeng Duan, Qi Huang, Tianhao Zhang, Xi Sun, Ting Feng, Lin Ma, Baoci Shan, Demin Li, Hua Liu
Retrosplenial cortex (RSC) plays a key role in various cognitive functions. The fiber connectivity of RSC had been reported in rodent and primate studies by tracer injection methods To explore structural and functional connectivity of two sub-regions of RSC, Brodmann area (BA)29 and BA30, we constructed fiber connectivity networks of two sub-regions by diffusion tensor imaging (DTI) tractography based on diffusion magnetic resonance imaging (MRI) and functional connectivity networks by resting-state functional MRI...
March 9, 2018: Neuroscience Letters
Avinash Rao, Hesham Soliman, Mayank Kaushal, Oleysa Motovylak, Aditya Vedantam, Matthew D Budde, Brian Schmit, Marjorie Wang, Shekar N Kurpad
BACKGROUND: Fractional anisotropy (FA) of the high cervical cord correlates with upper limb function in acute cervical cord injury. We investigated the correlation between preoperative FA at the level of maximal compression and functional recovery in a group of patients after decompressive surgery for cervical spondylotic myelopathy (CSM). OBJECTIVE: To determine the usefulness of FA as a biomarker for severity of CSM and as a prognostic biomarker for improvement after surgery...
February 23, 2018: Neurosurgery
Evangelia Tsolaki, Angela Downes, William Speier, W Jeff Elias, Nader Pouratian
Magnetic Resonance-guided Focused UltraSound (MRgFUS) offers an incisionless approach to treat essential tremor (ET). Due to lack of evident internal anatomy on traditional structural imaging, indirect targeting must still be used to localize the lesion. Here, we investigate the potential predictive value of probabilistic tractography guided thalamic targeting by defining how tractography-defined targets, lesion size and location, and clinical outcomes interrelate. MR imaging and clinical outcomes from 12 ET patients that underwent MRgFUS thalamotomy in a pilot study at the University of Virginia were evaluated in this analysis...
2018: NeuroImage: Clinical
Sanuji Gajamange, David Raffelt, Thijs Dhollander, Elaine Lui, Anneke van der Walt, Trevor Kilpatrick, Joanne Fielding, Alan Connelly, Scott Kolbe
Long term irreversible disability in multiple sclerosis (MS) is thought to be primarily driven by axonal degeneration. Axonal degeneration leads to degenerative atrophy, therefore early markers of axonal degeneration are required to predict clinical disability and treatment efficacy. Given that additional pathologies such as inflammation, demyelination and oedema are also present in MS, it is essential to develop axonal markers that are not confounded by these processes. The present study investigated a novel method for measuring axonal degeneration in MS based on high angular resolution diffusion magnetic resonance imaging...
2018: NeuroImage: Clinical
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