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Diffuse tensor imaging

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https://www.readbyqxmd.com/read/29054037/director-field-analysis-dfa-exploring-local-white-matter-geometric-structure-in-diffusion-mri
#1
Jian Cheng, Peter J Basser
In Diffusion Tensor Imaging (DTI) or High Angular Resolution Diffusion Imaging (HARDI), a tensor field or a spherical function field (e.g., an orientation distribution function field), can be estimated from measured diffusion weighted images. In this paper, inspired by the microscopic theoretical treatment of phases in liquid crystals, we introduce a novel mathematical framework, called Director Field Analysis (DFA), to study local geometric structural information of white matter based on the reconstructed tensor field or spherical function field: (1) We propose a set of mathematical tools to process general director data, which consists of dyadic tensors that have orientations but no direction...
October 11, 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/29053836/long-term-disability-progression-in-primary-progressive-multiple-sclerosis-a-15-year-study
#2
Maria A Rocca, Maria Pia Sormani, Marco Rovaris, Domenico Caputo, Angelo Ghezzi, Enrico Montanari, Antonio Bertolotto, Alice Laroni, Roberto Bergamaschi, Vittorio Martinelli, Giancarlo Comi, Massimo Filippi
Prognostic markers of primary progressive multiple sclerosis evolution are needed. We investigated the added value of magnetic resonance imaging measures of brain and cervical cord damage in predicting long-term clinical worsening of primary progressive multiple sclerosis compared to simple clinical assessment. In 54 patients, conventional and diffusion tensor brain scans and cervical cord T1-weighted scans were acquired at baseline and after 15 months. Clinical evaluation was performed after 5 and 15 years in 49 patients...
September 27, 2017: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/29053522/immediate-enhancement-of-nerve-function-using-a-novel-axonal-fusion-device-after-neurotmesis
#3
David Colton Riley, Richard B Boyer, Curt A Deister, Alonda C Pollins, Nancy L Cardwell, Nathaniel D Kelm, Mark D Does, Richard D Dortch, Ravinder Bamba, Robert Bruce Shack, Wesley P Thayer
BACKGROUND: The management of peripheral nerve injuries remains a large challenge for plastic surgeons. With the inability to fuse axonal endings, results after microsurgical nerve repair have been inconsistent. Our current nerve repair strategies rely upon the slow and lengthy process of axonal regeneration (~1 mm/d). Polyethylene glycol (PEG) has been investigated as a potential axonal fusion agent; however, the percentage of axonal fusion has been inconsistent. The purpose of this study was to identify a PEG delivery device to standardize outcomes after attempted axonal fusion with PEG...
October 19, 2017: Annals of Plastic Surgery
https://www.readbyqxmd.com/read/29053074/clinical-improvement-associated-with-targeted-interruption-of-the-cerebellothalamic-tract-following-mr-guided-focused-ultrasound-for-essential-tremor
#4
J Levi Chazen, Harini Sarva, Philip E Stieg, Robert J Min, Douglas J Ballon, Kane O Pryor, Paul M Riegelhaupt, Michael G Kaplitt
OBJECTIVE The objective of this study was to evaluate the utility of diffusion tensor imaging (DTI) tractography-based targeting of the dentatorubrothalamic tract (DRT) for magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy in patients with essential tremor (ET) and correlate postprocedural tract disruption with clinical outcomes. METHODS Four patients received preprocedural and immediate postprocedural DTI in addition to traditional anatomical MRI sequences for MRgFUS thalamotomy. Optimal ablation sites were selected based on the patient-specific location of the DRT as demonstrated by DTI (direct targeting) and correlated with traditional atlas-based measurements for thalamic ventral intermediate nucleus (Vim) lesioning (indirect targeting)...
October 20, 2017: Journal of Neurosurgery
https://www.readbyqxmd.com/read/29050387/temporal-lobe-networks-supporting-the-comprehension-of-spoken-words
#5
Leonardo Bonilha, Argye E Hillis, Gregory Hickok, Dirk B den Ouden, Chris Rorden, Julius Fridriksson
Auditory word comprehension is a cognitive process that involves the transformation of auditory signals into abstract concepts. Traditional lesion-based studies of stroke survivors with aphasia have suggested that neocortical regions adjacent to auditory cortex are primarily responsible for word comprehension. However, recent primary progressive aphasia and normal neurophysiological studies have challenged this concept, suggesting that the left temporal pole is crucial for word comprehension. Due to its vasculature, the temporal pole is not commonly completely lesioned in stroke survivors and this heterogeneity may have prevented its identification in lesion-based studies of auditory comprehension...
September 1, 2017: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/29049144/the-etiology-of-neuronal-development-in-craniosynostosis-a-working-hypothesis
#6
Eric D Brooks, Joel S Beckett, Jenny Yang, Andrew T Timberlake, Alexander H Sun, Carolyn Chuang, John A Persing
Craniosynostosis is one of the most common craniofacial conditions treated by neurologic and plastic surgeons. In addition to disfigurement, children with craniosynostosis experience significant cognitive dysfunction later in life. Surgery is performed in infancy to correct skull deformity; however, the field is at a crossroads regarding the best approach for correction. Since the cause of brain dysfunction in these patients has remained uncertain, the role and type of surgery might have in attenuating the later-observed cognitive deficits through impact on the brain has been unclear...
October 18, 2017: Journal of Craniofacial Surgery
https://www.readbyqxmd.com/read/29042619/diffusion-tensor-image-features-predict-idh-genotype-in-newly-diagnosed-who-grade-ii-iii-gliomas
#7
Paul Eichinger, Esther Alberts, Claire Delbridge, Stefano Trebeschi, Alexander Valentinitsch, Stefanie Bette, Thomas Huber, Jens Gempt, Bernhard Meyer, Juergen Schlegel, Claus Zimmer, Jan S Kirschke, Bjoern H Menze, Benedikt Wiestler
We hypothesized that machine learning analysis based on texture information from the preoperative MRI can predict IDH mutational status in newly diagnosed WHO grade II and III gliomas. This retrospective study included in total 79 consecutive patients with a newly diagnosed WHO grade II or III glioma. Local binary pattern texture features were generated from preoperative B0 and fractional anisotropy (FA) diffusion tensor imaging. Using a training set of 59 patients, a single hidden layer neural network was then trained on the texture features to predict IDH status...
October 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29041865/imaging-outcome-measures-for-progressive-multiple-sclerosis-trials
#8
Marcello Moccia, Nicola de Stefano, Frederik Barkhof
Imaging markers that are reliable, reproducible and sensitive to neurodegenerative changes in progressive multiple sclerosis (MS) can enhance the development of new medications with a neuroprotective mode-of-action. Accordingly, in recent years, a considerable number of imaging biomarkers have been included in phase 2 and 3 clinical trials in primary and secondary progressive MS. Brain lesion count and volume are markers of inflammation and demyelination and are important outcomes even in progressive MS trials...
October 2017: Multiple Sclerosis: Clinical and Laboratory Research
https://www.readbyqxmd.com/read/29038922/lower-fractional-anisotropy-in-the-gray-matter-of-amygdala-hippocampus-nucleus-accumbens-circuit-in-methamphetamine-users-an-in-vivo-diffusion-tensor-imaging-study
#9
Yadi Li, Wenhua Zhou, Haibo Dong, Wenwen Shen, Jianbing Zhang, Feng Li, Lingjun Zhang
The basolateral amygdala (BLA), hippocampal ventral subiculum, and nucleus accumbens (NAc) comprise the amygdala-hippocampus-NAc (AHN) circuit, which is implicated in drug seeking and reward. The goal of this study was to evaluate microstructural changes and relevant clinical features of the AHN circuit gray matter (GM) in methamphetamine (MA) users using diffusion tensor imaging (DTI). Thirty MA users and 30 age-matched normal volunteers underwent 3-T MR imaging to obtain structural T1-weighted images and DTI data...
October 16, 2017: Neurotoxicity Research
https://www.readbyqxmd.com/read/29038599/widespread-white-matter-microstructural-differences-in-schizophrenia-across-4322-individuals-results-from-the-enigma-schizophrenia-dti-working-group
#10
S Kelly, N Jahanshad, A Zalesky, P Kochunov, I Agartz, C Alloza, O A Andreassen, C Arango, N Banaj, S Bouix, C A Bousman, R M Brouwer, J Bruggemann, J Bustillo, W Cahn, V Calhoun, D Cannon, V Carr, S Catts, J Chen, J-X Chen, X Chen, C Chiapponi, Kl K Cho, V Ciullo, A S Corvin, B Crespo-Facorro, V Cropley, P De Rossi, C M Diaz-Caneja, E W Dickie, S Ehrlich, F-M Fan, J Faskowitz, H Fatouros-Bergman, L Flyckt, J M Ford, J-P Fouche, M Fukunaga, M Gill, D C Glahn, R Gollub, E D Goudzwaard, H Guo, R E Gur, R C Gur, T P Gurholt, R Hashimoto, S N Hatton, F A Henskens, D P Hibar, I B Hickie, L E Hong, J Horacek, F M Howells, H E Hulshoff Pol, C L Hyde, D Isaev, A Jablensky, P R Jansen, J Janssen, E G Jönsson, L A Jung, R S Kahn, Z Kikinis, K Liu, P Klauser, C Knöchel, M Kubicki, J Lagopoulos, C Langen, S Lawrie, R K Lenroot, K O Lim, C Lopez-Jaramillo, A Lyall, V Magnotta, R C W Mandl, D H Mathalon, R W McCarley, S McCarthy-Jones, C McDonald, S McEwen, A McIntosh, T Melicher, R I Mesholam-Gately, P T Michie, B Mowry, B A Mueller, D T Newell, P O'Donnell, V Oertel-Knöchel, L Oestreich, S A Paciga, C Pantelis, O Pasternak, G Pearlson, G R Pellicano, A Pereira, J Pineda Zapata, F Piras, S G Potkin, A Preda, P E Rasser, D R Roalf, R Roiz, A Roos, D Rotenberg, T D Satterthwaite, P Savadjiev, U Schall, R J Scott, M L Seal, L J Seidman, C Shannon Weickert, C D Whelan, M E Shenton, J S Kwon, G Spalletta, F Spaniel, E Sprooten, M Stäblein, D J Stein, S Sundram, Y Tan, S Tan, S Tang, H S Temmingh, L T Westlye, S Tønnesen, D Tordesillas-Gutierrez, N T Doan, J Vaidya, N E M van Haren, C D Vargas, D Vecchio, D Velakoulis, A Voineskos, J Q Voyvodic, Z Wang, P Wan, D Wei, T W Weickert, H Whalley, T White, T J Whitford, J D Wojcik, H Xiang, Z Xie, H Yamamori, F Yang, N Yao, G Zhang, J Zhao, T G M van Erp, J Turner, P M Thompson, G Donohoe
The regional distribution of white matter (WM) abnormalities in schizophrenia remains poorly understood, and reported disease effects on the brain vary widely between studies. In an effort to identify commonalities across studies, we perform what we believe is the first ever large-scale coordinated study of WM microstructural differences in schizophrenia. Our analysis consisted of 2359 healthy controls and 1963 schizophrenia patients from 29 independent international studies; we harmonized the processing and statistical analyses of diffusion tensor imaging (DTI) data across sites and meta-analyzed effects across studies...
October 17, 2017: Molecular Psychiatry
https://www.readbyqxmd.com/read/29036668/neurobiological-commonalities-and-distinctions-among-three-major-psychiatric-diagnostic-categories-a-structural-mri-study
#11
Miao Chang, Fay Y Womer, E Kale Edmiston, Chuan Bai, Qian Zhou, Xiaowei Jiang, Shengnan Wei, Yange Wei, Yuting Ye, Haiyan Huang, Yong He, Ke Xu, Yanqing Tang, Fei Wang
BACKGROUND: Schizophrenia (SZ), bipolar disorder (BD), and major depressive disorder (MDD) are distinct diagnostic categories in current psychiatric nosology, yet there is increasing evidence for shared clinical and biological features in these disorders. No previous studies have examined brain structural features concurrently in these 3 disorders. The aim of this study was to identify the extent of shared and distinct brain alterations in SZ, BD, and MDD. We examined gray matter (GM) volume and white matter (WM) integrity in a total of 485 individuals (135 with SZ, 86 with BD, 108 with MDD, and 156 healthy controls [HC]) who underwent high-resolution structural magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) at a single site...
June 13, 2017: Schizophrenia Bulletin
https://www.readbyqxmd.com/read/29034483/effect-of-sensory-and-motor-connectivity-on-hand-function-in-pediatric-hemiplegia
#12
Disha Gupta, Alexandre Barachant, Andrew M Gordon, Claudio Ferre, Hsing-Ching Kuo, Jason B Carmel, Kathleen M Friel
OBJECTIVE: We tested the hypothesis that somatosensory system injury would more strongly affect movement than motor system injury in children with unilateral cerebral palsy (USCP). This hypothesis was based on how somatosensory and corticospinal circuits adapt to injury during development: while the motor system can maintain connections to the impaired hand from the uninjured hemisphere, this doesn't occur in the somatosensory system. As a corollary, cortical injury strongly impairs sensory function, so we hypothesized that cortical lesions would impair hand function more than subcortical lesions...
October 16, 2017: Annals of Neurology
https://www.readbyqxmd.com/read/29034243/improving-surgical-outcome-using-diffusion-tensor-imaging-techniques-in-deep-brain-stimulation
#13
REVIEW
Angela An Qi See, Nicolas Kon Kam King
INTRODUCTION: Recent advances in surgical imaging include the use of diffusion tensor imaging (DTI) in deep brain stimulation (DBS) and provide a detailed view of the white matter tracts and their connections which are not seen with conventional magnetic resonance imaging. Given that the efficacy of DBS depends on the precise and accurate targeting of these circuits, better surgical planning using information obtained from DTI may lead to improved surgical outcome. We aim to review the available literature to evaluate the efficacy of such a strategy...
2017: Frontiers in Surgery
https://www.readbyqxmd.com/read/29033797/white-matter-abnormalities-in-children-with-hiv-infection-and-exposure
#14
Marcin Jankiewicz, Martha J Holmes, Paul A Taylor, Mark F Cotton, Barbara Laughton, André J W van der Kouwe, Ernesta M Meintjes
Background: Due to changes in guidelines and access to treatment, more children start combination antiretroviral therapy (ART) in infancy. With few studies examining the long-term effects of perinatal HIV infection and early ART on neurodevelopment, much is still unknown about brain maturation in the presence of HIV and ART. Follow-up studies of HIV infected (HIV+) children are important for monitoring brain development in the presence of HIV infection and ART. Methods: We use diffusion tensor imaging (DTI) to examine white matter (WM) in 65 HIV+ and 46 control (HIV exposed uninfected (HEU) and HIV unexposed uninfected (HU)) 7-year-old children...
2017: Frontiers in Neuroanatomy
https://www.readbyqxmd.com/read/29033027/anhedonia-following-early-life-adversity-involves-aberrant-interaction-of-reward-and-anxiety-circuits-and-is-reversed-by-partial-silencing-of-amygdala-corticotropin-releasing-hormone-gene
#15
Jessica L Bolton, Jenny Molet, Limor Regev, Yuncai Chen, Neggy Rismanchi, Elizabeth Haddad, Derek Z Yang, Andre Obenaus, Tallie Z Baram
BACKGROUND: Anhedonia, the diminished ability to experience pleasure, is an important dimensional entity linked to depression, schizophrenia, and other emotional disorders, but its origins and mechanisms are poorly understood. We have previously identified anhedonia, manifest as decreased sucrose preference and social play, in adolescent male rats that experienced chronic early-life adversity/stress (CES). Here we probed the molecular, cellular, and circuit processes underlying CES-induced anhedonia and tested them mechanistically...
September 7, 2017: Biological Psychiatry
https://www.readbyqxmd.com/read/29032776/neuropsychological-recovery-trajectories-in-moderate-to-severe-traumatic-brain-injury-influence-of-patient-characteristics-and-diffuse-axonal-injury
#16
Amanda R Rabinowitz, Tessa Hart, John Whyte, Junghoon Kim
OBJECTIVES: The goal of the present study was to elucidate the influence of demographic and neuropathological moderators on the longitudinal trajectory neuropsychological functions during the first year after moderate to severe traumatic brain injury (TBI). In addition to examining demographic moderators such as age and education, we included a measure of whole-brain diffuse axonal injury (DAI), and examined measures of processing speed (PS), executive function (EF), and verbal learning (VL) separately...
October 16, 2017: Journal of the International Neuropsychological Society: JINS
https://www.readbyqxmd.com/read/29032192/age-dependent-association-of-thyroid-function-with-brain-morphology-and-microstructural-organization-evidence-from-brain-imaging
#17
Layal Chaker, Lotte G M Cremers, Tim I M Korevaar, Marius de Groot, Abbas Dehghan, Oscar H Franco, Wiro J Niessen, M Arfan Ikram, Robin P Peeters, Meike W Vernooij
Thyroid hormone (TH) is crucial during neurodevelopment, but high levels of TH have been linked to neurodegenerative disorders. No data on the association of thyroid function with brain imaging in the general population are available. We therefore investigated the association of thyroid-stimulating hormone and free thyroxine (FT4) with magnetic resonance imaging (MRI)-derived total intracranial volume, brain tissue volumes, and diffusion tensor imaging measures of white matter microstructure in 4683 dementia- and stroke-free participants (mean age 60...
September 22, 2017: Neurobiology of Aging
https://www.readbyqxmd.com/read/29032126/weekly-follow-up-of-acute-lesions-in-three-early-multiple-sclerosis-patients-using-mr-spectroscopy-and-diffusion
#18
Gabriel Kocevar, Claudio Stamile, Salem Hannoun, Jean-Amédée Roch, Françoise Durand-Dubief, Sandra Vukusic, François Cotton, Dominique Sappey-Marinier
OBJECT: Pathophysiological mechanisms underlying multiple sclerosis (MS) lesion formation, including inflammation, demyelination/remyelination and axonal damage, and their temporal evolution are still not clearly understood. To this end, three acute white matter lesions were monitored using a weekly multimodal magnetic resonance (MR) protocol. MATERIALS AND METHODS: Three untreated patients with early relapsing-remitting MS and one healthy control subject were followed weekly for two months...
October 12, 2017: Journal of Neuroradiology. Journal de Neuroradiologie
https://www.readbyqxmd.com/read/29031764/combined-resting-state-functional-magnetic-resonance-imaging-and-diffusion-tensor-imaging-study-in-patients-with-idiopathic-restless-legs-syndrome
#19
Yaoyao Zhuo, Yuncheng Wu, Yanhong Xu, Lunbo Lu, Ting Li, Xifu Wang, Kangan Li
OBJECTIVE: Restless legs syndrome (RLS) is a common neurological disorder characterized by an urge to move the legs along with paraesthesia deep within them. In this study, we aimed to use diffusion tensor imaging (DTI) and regional homogeneity (ReHo) to investigate the changes in regional spontaneous brain activity change for RLS patients against age- and gender-matched normal control (NC) subjects. METHODS: A total of 35 RLS patients and 27 age- and gender-matched NC subjects were recruited for group comparison research that used DTI and ReHo techniques...
October 2017: Sleep Medicine
https://www.readbyqxmd.com/read/29031602/microstructural-mri-basis-of-the-cognitive-functions-in-patients-with-spinocerebellar-ataxia-type-2
#20
G Olivito, M Lupo, C Iacobacci, S Clausi, S Romano, M Masciullo, M Molinari, M Cercignani, M Bozzali, M Leggio
Spinocerebellarataxiatype2(SCA2) is an autosomal dominant neurodegenerative disease involving the cerebellum. The particular atrophy pattern results in some typical clinical features mainly including motor deficits. In addition, the presence of cognitive impairments, involving language, visuospatial and executive functions, has been also shown in SCA2 patients and it is now widely accepted as a feature of the disease. The aim of the study is to investigate the microstructural patterns and the anatomo-functional substrate that could account for the cognitive symptomatology observed in SCA2 patients...
October 11, 2017: Neuroscience
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