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Tractography

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https://www.readbyqxmd.com/read/28092278/delayed-onset-central-pain-due-to-degeneration-of-ischemic-transcallosal-fibers-after-corpus-callosum-hemorrhage
#1
Sung Ho Jang, Chul Hoon Chang, Young Jin Jung, Han Do Lee
AIMS: A patient developed delayed-onset central pain due to degeneration of the spinothalamic tract resulting from degeneration of the ischemic transcallosal fibers, in the aftermath of a corpus callosum (CC) hemorrhage. The detection and diagnosis of these lesions using diffusion tensor tractography are described. METHODS: A 59-yr-old man underwent conservative management for hemorrhages in the CC and lateral ventricle that resulted from hitting his head against a wall while falling...
January 13, 2017: American Journal of Physical Medicine & Rehabilitation
https://www.readbyqxmd.com/read/28090602/probabilistic-tractography-for-topographically-organized-connectomes
#2
Dogu Baran Aydogan, Yonggang Shi
While tractography is widely used in brain imaging research, its quantitative validation is highly difficult. Many fiber systems, however, have well-known topographic organization which can even be quantitatively mapped such as the retinotopy of visual pathway. Motivated by this previously untapped anatomical knowledge, we develop a novel tractography method that preserves both topographic and geometric regularity of fiber systems. For topographic preservation, we propose a novel likelihood function that tests the match between parallel curves and fiber orientation distributions...
October 2016: Medical Image Computing and Computer-assisted Intervention: MICCAI ..
https://www.readbyqxmd.com/read/28088391/changes-in-the-cerebellar-and-cerebro-cerebellar-circuit-in-type-2-diabetes
#3
Peng Fang, Jie An, Xin Tan, Ling-Li Zeng, Hui Shen, Shijun Qiu, Dewen Hu
Currently, 422 million adults suffer from diabetes worldwide, leading to tremendous disabilities and a great burden to families and society. Functional and structural MRIs have demonstrated that patients with type 2 diabetes mellitus (T2DM) exhibit abnormalities in brain regions in the cerebral cortex. However, the changes of cerebellar anatomical connections in diabetic patients remains unclear. In the current study, diffusion tensor imaging deterministic tractography and statistical analysis were employed to investigate abnormal cerebellar anatomical connections in diabetic patients...
January 11, 2017: Brain Research Bulletin
https://www.readbyqxmd.com/read/28086899/evaluations-of-diffusion-tensor-image-registration-based-on-fiber-tractography
#4
Yi Wang, Yu Shen, Dongyang Liu, Guoqin Li, Zhe Guo, Yangyu Fan, Yilong Niu
BACKGROUND: Diffusion Tensor Magnetic Resonance Imaging (DT-MRI, also known as DTI) measures the diffusion properties of water molecules in tissues and to date is one of the main techniques that can effectively study the microstructures of the brain in vivo. Presently, evaluation of DTI registration techniques is still in an initial stage of development. METHODS AND RESULTS: In this paper, six well-known open source DTI registration algorithms: Elastic, Rigid, Affine, DTI-TK, FSL and SyN were applied on 11 subjects from an open-access dataset, among which one was randomly chosen as the template...
January 10, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28079471/pre-implant-modeling-of-depth-lead-placement-in-white-matter-for-maximizing-the-extent-of-cortical-activation-during-direct-neurostimulation-therapy
#5
Leopoldo Cendejas Zaragoza, Richard W Byrne, Marvin A Rossi
INTRODUCTION: The objective of this work was to predict preoperatively the maximum extent to which direct stimulation therapy can propagate through an epileptic circuit for stabilizing refractory focal-onset epilepsy. A pre-surgical workflow is presented which comprises a computationally intensive process for calculating the volume of cortical activation (VOCA) surrounding cylindrical depth contacts virtually placed in white matter. The process employs an activation function (AF) derived from cable modeling of an axon...
January 12, 2017: Neurological Research
https://www.readbyqxmd.com/read/28076974/topological-organization-of-whole-brain-white-matter-in-hiv-infection
#6
Laurie M Baker, Sarah Cooley, Ryan P Cabeen, David H Laidlaw, John A Joska, Jacqueline Hoare, Dan J Stein, Jodi Heaps-Woodruff, Lauren E Salminen, Robert H Paul
Infection with human immunodeficiency virus (HIV) is associated with neuroimaging alterations. However, little is known about the topological organization of whole-brain networks and the corresponding association with cognition. As such, we examined structural whole-brain white matter connectivity patterns and cognitive performance in 29 HIV+ young adults (mean age = 25.9) with limited or no HIV treatment history. HIV+ participants and demographically similar HIV- controls (n = 16) residing in South Africa underwent magnetic resonance imaging (MRI) and neuropsychological testing...
January 11, 2017: Brain Connectivity
https://www.readbyqxmd.com/read/28072702/hypersomnia-due-to-injury-of-the-ventral-ascending-reticular-activating-system-following-cerebellar-herniation-a-case-report
#7
Sung Ho Jang, Chul Hoon Chang, Young Jin Jung, Hyeok Gyu Kwon
RATIONALE: We report on a patient with hypersomnia who showed injury of the lower ascending reticular activating system (ARAS) following cerebellar herniation due to a cerebellar infarct, detected on diffusion tensor tractography (DTT). PATIENT CONCERNS: A 53-year-old male patient was diagnosed as a left cerebellar infarct, and underwent decompressive suboccipital craniectomy due to brain edema at 2 days after the onset of a cerebellar infarct. Three weeks after onset when the patient started rehabilitation, he showed hypersomnia without impairment of consciousness; he fell asleep most of daytime without external stimulation and showed an abnormal score on the Epworth Sleepiness Scale: 15 (full score: 24, cut off for hypersomnia: 10)...
January 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28067973/simultaneous-multislice-readout-segmented-echo-planar-imaging-for-accelerated-diffusion-tensor-imaging-of-the-mandibular-nerve-a-feasibility-study
#8
Andrei Manoliu, Michael Ho, Marco Piccirelli, Daniel Nanz, Lukas Filli, Evelyn Dappa, Wei Liu, Dominik A Ettlin, Andreas Boss, Gustav Andreisek, Felix P Kuhn
PURPOSE: To assess the feasibility of diffusion tensor imaging (DTI) using simultaneous multislice (SMS) acquisition with blipped controlled aliasing in parallel imaging (CAIPI) for accelerated readout-segmented echo planar imaging (rs-EPI) of the mandibular nerves. DTI of the mandibular nerves using EPI is challenging due to susceptibility artifacts. Rs-EPI is less prone to artifacts but associated with longer scan durations. MATERIALS AND METHODS: Eight asymptomatic volunteers were imaged at 3T using a 64-channel head/neck coil...
January 9, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28067245/effect-of-hierarchically-aligned-fibrin-hydrogel-in-regeneration-of-spinal-cord-injury-demonstrated-by-tractography-a-pilot-study
#9
Zhenxia Zhang, Shenglian Yao, Sheng Xie, Xiumei Wang, Feiyan Chang, Jie Luo, Jingming Wang, Jun Fu
Some studies have reported that scaffold or cell-based transplantation may improve functional recovery following SCI, but no imaging information regarding regeneration has been provided to date. This study used tractography to show the regenerating process induced by a new biomaterial-aligned fibrin hydrogel (AFG). A total of eight canines subjected to SCI procedures were assigned to the control or the AFG group. AFG was implanted into the SCI lesion immediately after injury in 5 canines. A follow-up was performed at 12 weeks to evaluate the therapeutic effect including the hindlimb functional recovery, anisotropy and continuity of fibers on tractography...
January 9, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28066709/alterations-of-white-matter-structural-networks-in-patients-with-non-neuropsychiatric-systemic-lupus-erythematosus-identified-by-probabilistic-tractography-and-connectivity-based-analyses
#10
Man Xu, Xiangliang Tan, Xinyuan Zhang, Yihao Guo, Yingjie Mei, Qianjin Feng, Yikai Xu, Yanqiu Feng
PURPOSE: Systemic lupus erythematosus (SLE) is a chronic inflammatory female-predominant autoimmune disease that can affect the central nervous system and exhibit neuropsychiatric symptoms. In SLE patients without neuropsychiatric symptoms (non-NPSLE), recent diffusion tensor imaging studies showed white matter abnormalities in their brains. The present study investigated the entire brain white matter structural connectivity in non-NPSLE patients by using probabilistic tractography and connectivity-based analyses...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28063366/white-matter-lesions-relate-to-tract-specific-reductions-in-functional-connectivity
#11
Carolyn D Langen, Hazel I Zonneveld, Tonya White, Wyke Huizinga, Lotte G M Cremers, Marius de Groot, Mohammad Arfan Ikram, Wiro J Niessen, Meike W Vernooij
White matter lesions play a role in cognitive decline and dementia. One presumed pathway is through disconnection of functional networks. Little is known about location-specific effects of lesions on functional connectivity. This study examined location-specific effects within anatomically-defined white matter tracts in 1584 participants of the Rotterdam Study, aged 50-95. Tracts were delineated from diffusion magnetic resonance images using probabilistic tractography. Lesions were segmented on fluid-attenuated inversion recovery images...
December 14, 2016: Neurobiology of Aging
https://www.readbyqxmd.com/read/28059709/microstructure-of-the-default-mode-network-in-preterm-infants
#12
J Cui, O Tymofiyeva, R Desikan, T Flynn, H Kim, D Gano, C P Hess, D M Ferriero, A J Barkovich, D Xu
BACKGROUND AND PURPOSE: Diffusion and fMRI has been providing insights to brain development in addition to anatomic imaging. This study aimed to evaluate the microstructure of white matter tracts underlying the default mode network in premature infants by using resting-state functional MR imaging in conjunction with diffusion tensor imaging-based tractography. MATERIALS AND METHODS: A cohort of 44 preterm infants underwent structural T1-weighted imaging, resting-state fMRI, and DTI at 3T, including 21 infants with brain injuries and 23 infants with normal-appearing structural imaging as controls...
November 10, 2016: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28054634/within-brain-area-tractography-suggests-local-modularity-using-high-resolution-connectomics
#13
Peter N Taylor, Yujiang Wang, Marcus Kaiser
Previous structural brain connectivity studies have mainly focussed on the macroscopic scale of around 1,000 or fewer brain areas (network nodes). However, it has recently been demonstrated that high resolution structural connectomes of around 50,000 nodes can be generated reproducibly. In this study, we infer high resolution brain connectivity matrices using diffusion imaging data from the Human Connectome Project. With such high resolution we are able to analyse networks within brain areas in a single subject...
January 5, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28050345/functional-mri-vs-navigated-tms-to-optimize-m1-seed-volume-delineation-for-dti-tractography-a-prospective-study-in-patients-with-brain-tumours-adjacent-to-the-corticospinal-tract
#14
Carolin Weiss Lucas, Irada Tursunova, Volker Neuschmelting, Charlotte Nettekoven, Ana-Maria Oros-Peusquens, Gabriele Stoffels, Andrea Maria Faymonville, Shah N Jon, Karl Josef Langen, Hannah Lockau, Roland Goldbrunner, Christian Grefkes
BACKGROUND: DTI-based tractography is an increasingly important tool for planning brain surgery in patients suffering from brain tumours. However, there is an ongoing debate which tracking approaches yield the most valid results. Especially the use of functional localizer data such as navigated transcranial magnetic stimulation (nTMS) or functional magnetic resonance imaging (fMRI) seem to improve fibre tracking data in conditions where anatomical landmarks are less informative due to tumour-induced distortions of the gyral anatomy...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28050344/structural-networks-involved-in-attention-and-executive-functions-in-multiple-sclerosis
#15
Sara Llufriu, Eloy Martinez-Heras, Elisabeth Solana, Nuria Sola-Valls, Maria Sepulveda, Yolanda Blanco, Elena H Martinez-Lapiscina, Magi Andorra, Pablo Villoslada, Alberto Prats-Galino, Albert Saiz
Attention and executive deficits are disabling symptoms in multiple sclerosis (MS) that have been related to disconnection mechanisms. We aimed to investigate changes in structural connectivity in MS and their association with attention and executive performance applying an improved framework that combines high order probabilistic tractography and anatomical exclusion criteria postprocessing. We compared graph theory metrics of structural networks and fractional anisotropy (FA) of white matter (WM) connections or edges between 72 MS subjects and 38 healthy volunteers (HV) and assessed their correlation with cognition...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28046289/su-f-j-160-clinical-evaluation-of-targeting-accuracy-in-radiosurgery-using-tractography
#16
R Juh, T Suh, J Han, C Kim, C Oh
PURPOSE: Focal radiosurgery is a common treatment modality for trigeminal neuralgia (TN), a neuropathic facial pain condition. Assessment of treatment effectiveness is primarily clinical, given the paucity of investigational tools to assess trigeminal nerve changes. The efficiency of radiosurgery is related to its highly precise targeting. We assessed clinically the targeting accuracy of radiosurgery with Gamma knife. We hypothesized that trigeminal tractography provides more information than 2D-MR imaging, allowing detection of unique, focal changes in the target area after radiosurgery...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28039039/group-comparison-of-cortical-fiber-connectivity-map-an-application-between-post-stroke-patients-and-healthy-subjects
#17
Kai Liu, Teng Zhang, Winnie C W Chu, Vincent C T Mok, Defeng Wang, Lin Shi
Structural connectome measurement combined with diffusion magnetic resonance imaging (MRI) and tractography allows generation of a whole-brain connectome. However, current cortical structural connectivity (SC) measurements have not been well combined with the vertex-wise multi-subjects statistical analysis. The aim of this study was to examine the feasibility of using group comparison vertex-wise analysis for cortical SC measurement. A fiber connectivity density (FiCD) method based on a combination of a diffusion fiber tracking technique and cortical surface-based analysis was used to measure the whole-brain cortical SC map (FiCD map)...
December 28, 2016: Neuroscience
https://www.readbyqxmd.com/read/28038362/brain-connectivity-networks-and-longitudinal-trajectories-of-depression-symptoms-in-adolescence
#18
Rachel Ellis, Marc L Seal, Christopher Adamson, Richard Beare, Julian G Simmons, Sarah Whittle, Nicholas B Allen
High levels of depression during adolescence may contribute to the risk for future depression later in life. This study examined the relationship between the developmental timing of depressive symptoms, and brain structural outcomes in late adolescence. In a prior work, we examined longitudinal trajectories of depressive symptoms in 243 adolescents (121 males and 122 females), and identified four subgroups: a normative group with stable low levels of depression, two groups with declining symptoms, and one group with increasing symptoms...
December 21, 2016: Psychiatry Research
https://www.readbyqxmd.com/read/28034996/a-fully-automated-atlas-based-approach-for-superior-cerebellar-peduncle-evaluation-in-progressive-supranuclear-palsy-phenotypes
#19
G Nicoletti, M E Caligiuri, A Cherubini, M Morelli, F Novellino, G Arabia, M Salsone, A Quattrone
BACKGROUND AND PURPOSE: The superior cerebellar peduncle is damaged in progressive supranuclear palsy. However, alterations differ between progressive supranuclear palsy with Richardson syndrome and progressive supranuclear palsy-parkinsonism. In this study, we propose an automated tool for superior cerebellar peduncle integrity assessment and test its performance in patients with progressive supranuclear palsy with Richardson syndrome, progressive supranuclear palsy-parkinsonism, Parkinson disease, and healthy controls...
December 29, 2016: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28034765/reproducibility-of-superficial-white-matter-tracts-using-diffusion-weighted-imaging-tractography
#20
Miguel Guevara, Claudio Rom├ín, Josselin Houenou, Delphine Duclap, Cyril Poupon, Jean Fran├žois Mangin, Pamela Guevara
Human brain connection map is far from being complete. In particular the study of the superficial white matter (SWM) is an unachieved task. Its description is essential for the understanding of human brain function and the study of pathogenesis triggered by abnormal connectivity. In this work we automatically created a multi-subject atlas of SWM diffusion-based bundles of the whole brain. For each subject, the complete cortico-cortical tractogram is first split into sub-tractograms connecting pairs of gyri...
December 26, 2016: NeuroImage
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