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https://www.readbyqxmd.com/read/28334658/extraction-of-the-3d-local-orientation-of-myocytes-in-human-cardiac-tissue-using-x-ray-phase-contrast-micro-tomography-and-multi-scale-analysis
#1
François Varray, Iulia Mirea, Max Langer, Françoise Peyrin, Laurent Fanton, Isabelle E Magnin
This paper presents a methodology to access the 3D local myocyte arrangements in fresh human post-mortem heart samples. We investigated the cardiac micro-structure at a high and isotropic resolution of 3.5 µm in three dimensions using X-ray phase micro-tomography at the European Synchrotron Radiation Facility. We then processed the reconstructed volumes to extract the 3D local orientation of the myocytes using a multi-scale approach with no segmentation. We created a simplified 3D model of tissue sample made of simulated myocytes with known size and orientations, to evaluate our orientation extraction method...
February 20, 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/28334314/a-template-and-probabilistic-atlas-of-the-human-sensorimotor-tracts-using-diffusion-mri
#2
Derek B Archer, David E Vaillancourt, Stephen A Coombes
The purpose of this study was to develop a high-resolution sensorimotor area tract template (SMATT) which segments corticofugal tracts based on 6 cortical regions in primary motor cortex, dorsal premotor cortex, ventral premotor cortex, supplementary motor area (SMA), pre-supplementary motor area (preSMA), and primary somatosensory cortex using diffusion tensor imaging. Individual probabilistic tractography analyses were conducted in 100 subjects using the highest resolution data currently available. Tractography results were refined using a novel algorithm to objectively determine slice level thresholds that best minimized overlap between tracts while preserving tract volume...
March 14, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28334159/characterization-of-white-matter-tracts-by-diffusion-mr-tractography-in-cat-and-ferret-that-have-similar-gyral-patterns
#3
Avilash Das, Emi Takahashi
The developmental relationships between gyral structures and white matter tracts have long been debated, but it is still difficult to discern whether they influence each other's development or are causally related. To explore this topic, this study used cats and ferrets as models for species that share similar gyral folding patterns and imaged with diffusion magnetic resonance imaging to compare white matter innervations in homologous gyri and other brain regions. Adult cat and ferret brains were analyzed via diffusion spectrum imaging tractography and homologous regions of interest were compared...
March 1, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28333589/a-unified-theory-of-neuro-mri-data-shows-scale-free-nature-of-connectivity-modes
#4
Vitaly L Galinsky, Lawrence R Frank
A primary goal of many neuroimaging studies that use magnetic resonance imaging (MRI) is to deduce the structure-function relationships in the human brain using data from the three major neuro-MRI modalities: high-resolution anatomical, diffusion tensor imaging, and functional MRI. To date, the general procedure for analyzing these data is to combine the results derived independently from each of these modalities. In this article, we develop a new theoretical and computational approach for combining these different MRI modalities into a powerful and versatile framework that combines our recently developed methods for morphological shape analysis and segmentation, simultaneous local diffusion estimation and global tractography, and nonlinear and nongaussian spatial-temporal activation pattern classification and ranking, as well as our fast and accurate approach for nonlinear registration between modalities...
March 23, 2017: Neural Computation
https://www.readbyqxmd.com/read/28330041/retinal-tractography-influence-of-diffusion-acquisition-ocular-laterality-and-ocular-dominance-in-healthy-subjects
#5
Clément Jean, Arnaud Attyé, Sylvie Grand, Augustin Lecler, Christophe Chiquet, Florent Aptel, Laurent Lamalle, Alexandre Krainik
PURPOSE: Exploration of the human retina has never been described with MRI tractography, supposedly because of ocular movement-related artifacts and imaging distortions with EPI diffusion acquisition. In this work, we used track-weighting imaging to assess retinal fascicles. Diffusion acquisition parameters influence was studied and the relationship between variability and ocular laterality and ocular dominance was explored. MATERIALS AND METHODS: Twenty healthy subjects underwent MRI, with retinal tractography calculated with the constrained spherical deconvolution model...
March 2017: Journal of Neuroradiology. Journal de Neuroradiologie
https://www.readbyqxmd.com/read/28330019/facial-nerve-tractography-a-new-tool-to-detect-perineural-invasion-in-parotid-cancers
#6
René-Charles Rouchy, Arnaud Attyé, Irène Troprès, Maud Medici, Adrian Kastler, Christian Righini, Alexandre Krainik
PURPOSE: To determine whether magnetic resonance (MR) tractography of facial nerve (VIIn) is useful to detect perineural invasion in case of parotid cancers. MATERIALS AND METHODS: Thirty patients, aged 18 or over, were enrolled in this prospective study between December 2013 and March 2016 (IRB 5891), with a diagnosis of parotid tumors (15 malignant, 15 benign). They have undergone preoperative MR scans (3.0-T) before surgical management. The parameters of the diffusion-weighted (DW) sequence were b-value of 1000s/mm(2); 32 directions; voxel size: 2mm isotropic; scan time: 9' The post-processing generates whole-neck constrained spherical deconvolution (CSD)-based tractography data and super-resolution track-weighted imaging (TWI) technique...
March 2017: Journal of Neuroradiology. Journal de Neuroradiologie
https://www.readbyqxmd.com/read/28327991/letter-visualization-of-cranial-nerves-using-high-definition-fiber-tractography
#7
Kaichuang Yang, Tejashwi Shrestha, Manish Kolakshyapati
No abstract text is available yet for this article.
February 20, 2017: Neurosurgery
https://www.readbyqxmd.com/read/28325026/application-of-dti-connectivity-in-lateralization-of-mtle
#8
Mohammad R Nazem-Zadeh, Susan M Bowyer, John E Moran, Esmaeil Davoodi-Bojd, Andrew Zillgitt, Hassan Bagher-Ebadian, Fariborz Mahmoudi, Kost V Elisevich, Hamid Soltanian-Zadeh
Diffusion tensor imaging (DTI) is a noninvasive imaging method for measuring the diffusion properties of the underlying white matter tracts through which epileptiform activity is propagated. This study investigates the structural abnormalities quantified by DTI in mesial temporal lobe epilepsy (mTLE). Fiber tracts passing through 54 anatomical sites in 12 adult mTLE patients and 12 age- and gender-matched controls were identified using DTI tractography. DTI nodal degree (ND) and laterality index were then calculated...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28324881/optic-radiation-tractography-and-visual-field-deficits-in-laser-interstitial-thermal-therapy-for-amygdalohippocampectomy-in-patients-with-mesial-temporal-lobe-epilepsy
#9
Dali Yin, John A Thompson, Cornelia Drees, Steven G Ojemann, Lidia Nagae, Victoria S Pelak, Aviva Abosch
BACKGROUND/AIMS: Laser interstitial thermal therapy (LITT) has become an alternative to open-resective surgery for refractory mesial temporal lobe epilepsy (MTLE). Occurrence of visual field defects (VFDs) following open surgery for MTLE is reported at 52-100%. We examined the rate of VFDs following LITT for amygdalohippocampectomy (AHE) and correlated the occurrence of VFDs with damage to the optic radiations, assessed by diffusion tensor tractography (DTI). METHODS: We performed a retrospective analysis of 5 patients who underwent LITT-AHE for medically refractory MTLE...
March 22, 2017: Stereotactic and Functional Neurosurgery
https://www.readbyqxmd.com/read/28322222/white-matter-maturation-is-associated-with-the-emergence-of-theory-of-mind-in-early-childhood
#10
Charlotte Grosse Wiesmann, Jan Schreiber, Tania Singer, Nikolaus Steinbeis, Angela D Friederici
The ability to attribute mental states to other individuals is crucial for human cognition. A milestone of this ability is reached around the age of 4, when children start understanding that others can have false beliefs about the world. The neural basis supporting this critical step is currently unknown. Here, we relate this behavioural change to the maturation of white matter structure in 3- and 4-year-old children. Tract-based spatial statistics and probabilistic tractography show that the developmental breakthrough in false belief understanding is associated with age-related changes in local white matter structure in temporoparietal regions, the precuneus and medial prefrontal cortex, and with increased dorsal white matter connectivity between temporoparietal and inferior frontal regions...
March 21, 2017: Nature Communications
https://www.readbyqxmd.com/read/28320182/axial-mr-diffusion-tensor-imaging-and-tractography-in-clinical-diagnosed-and-pathology-confirmed-cervical-spinal-cord-astrocytoma
#11
Mangsuo Zhao, Bingxin Shi, Tuoyu Chen, Yuqi Zhang, Tongchao Geng, Liyan Qiao, Mingjie Zhang, Le He, Huancong Zuo, Guihuai Wang
OBJECTIVE: To evaluate the diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) features of cervical spinal cord astrocytoma. METHODS: Eleven patients with cervical spinal cord astrocytomas and 10 healthy volunteers were recruited in this study. Conventional magnetic resonance imaging (MRI) and axial DTI were performed on a 3.0T MRI system. Apparent diffusion coefficient (ADC), fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) values for the lesions were measured...
April 15, 2017: Journal of the Neurological Sciences
https://www.readbyqxmd.com/read/28318839/linking-optic-radiation-volume-to-visual-perception-in-schizophrenia-and-bipolar-disorder
#12
Eric A Reavis, Junghee Lee, Jonathan K Wynn, Katherine L Narr, Stephanie N Njau, Stephen A Engel, Michael F Green
People with schizophrenia typically show visual processing deficits on masking tasks and other performance-based measures, while people with bipolar disorder may have related deficits. The etiology of these deficits is not well understood. Most neuroscientific studies of perception in schizophrenia and bipolar disorder have focused on visual processing areas in the cerebral cortex, but perception also depends on earlier components of the visual system that few studies have examined in these disorders. Using diffusion weighted imaging (DWI), we investigated the structure of the primary sensory input pathway to the cortical visual system: the optic radiations...
March 16, 2017: Schizophrenia Research
https://www.readbyqxmd.com/read/28315957/right-sided-dominance-of-the-bilateral-vestibular-system-in-the-upper-brainstem-and-thalamus
#13
Marianne Dieterich, V Kirsch, T Brandt
MRI diffusion tensor imaging tractography was performed on the bilateral vestibular brainstem pathways, which run from the vestibular nuclei via the paramedian and posterolateral thalamic subnuclei to the parieto-insular vestibular cortex. Twenty-one right-handed healthy subjects participated. Quantitative analysis revealed a rope-ladder-like system of vestibular pathways in the brainstem with crossings at pontine and mesencephalic levels. Three structural types of right-left fiber distributions could be delineated: (1) evenly distributed pathways at the lower pontine level from the vestibular nuclei to the pontine crossing, (2) a moderate, pontomesencephalic right-sided lateralization between the pontine and mesencephalic crossings, and (3) a further increase of the right-sided lateralization above the mesencephalic crossing leading to the thalamic vestibular subnuclei...
March 18, 2017: Journal of Neurology
https://www.readbyqxmd.com/read/28315741/individual-classification-of-alzheimer-s-disease-with-diffusion-magnetic-resonance-imaging
#14
Tijn M Schouten, Marisa Koini, Frank de Vos, Stephan Seiler, Mark de Rooij, Anita Lechner, Reinhold Schmidt, Martijn van den Heuvel, Jeroen van der Grond, Serge A R B Rombouts
Diffusion magnetic resonance imaging (MRI) is a powerful non-invasive method to study white matter integrity, and is sensitive to detect differences in Alzheimer's disease (AD) patients. Diffusion MRI may be able to contribute towards reliable diagnosis of AD. We used diffusion MRI to classify AD patients (N=77), and controls (N=173). We use different methods to extract information from the diffusion MRI data. First, we use the voxel-wise diffusion tensor measures that have been skeletonised using tract based spatial statistics...
March 15, 2017: NeuroImage
https://www.readbyqxmd.com/read/28304232/a-systematic-evaluation-of-intraoperative-white-matter-tract-shift-in-pediatric-epilepsy-surgery-using-high-field-mri-and-probabilistic-high-angular-resolution-diffusion-imaging-tractography
#15
Joseph Yuan-Mou Yang, Richard Beare, Marc L Seal, A Simon Harvey, Vicki A Anderson, Wirginia J Maixner
OBJECTIVE Characterization of intraoperative white matter tract (WMT) shift has the potential to compensate for neuronavigation inaccuracies using preoperative brain imaging. This study aimed to quantify and characterize intraoperative WMT shift from the global hemispheric to the regional tract-based scale and to investigate the impact of intraoperative factors (IOFs). METHODS High angular resolution diffusion imaging (HARDI) diffusion-weighted data were acquired over 5 consecutive perioperative time points (MR1 to MR5) in 16 epilepsy patients (8 male; mean age 9...
March 17, 2017: Journal of Neurosurgery. Pediatrics
https://www.readbyqxmd.com/read/28303959/altered-microstructure-rather-than-morphology-in-the-corpus-callosum-after-lower-limb-amputation
#16
Zhichao Li, Chuanming Li, Lingzhong Fan, Guangyao Jiang, Jixiang Wu, Tianzi Jiang, Xuntao Yin, Jian Wang
The corpus callosum (CC) has been implicated in the reorganization of the brain following amputation. However, it is unclear which regions of the CC are involved in this process. In this study, we explored the morphometric and microstructural changes in CC subregions in patients with unilateral lower limb amputation. Thirty-eight patients and 38 age- and gender-matched normal controls were included. The CC was divided into five regions, and the area, thickness and diffusion parameters of each region were investigated...
March 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28303377/the-differences-of-the-precommissural-and-postcommissural-fornix-in-the-hippocampal-location-a-diffusion-tensor-tractography-study
#17
Sung Ho Jang, Sang Seok Yeo
PURPOSE: The precommissural fornix and postcommissural fornix have different connections to the basal forebrain and septal region, and mammillary body, respectively. However, little is known about the differences of the precommissural fornix and postcommissural fornix in the hippocampal location. In this study, using diffusion tensor tractography, we investigated the differences of the precommissural fornix and postcommissural fornix in the hippocampal location. METHODS: We recruited 25 healthy volunteers for this study...
March 16, 2017: Neuroradiology
https://www.readbyqxmd.com/read/28298033/diffusion-tractography-imaging-guided-frameless-linear-accelerator-stereotactic-radiosurgical-thalamotomy-for-tremor-case-report
#18
Won Kim, Justin Sharim, Stephen Tenn, Tania Kaprealian, Yvette Bordelon, Nzhde Agazaryan, Nader Pouratian
Essential tremor and Parkinson's disease-associated tremor are extremely prevalent within the field of movement disorders. The ventral intermediate (VIM) nucleus of the thalamus has been commonly used as both a neuromodulatory and neuroablative target for the treatment of these forms of tremor. With both deep brain stimulation and Gamma Knife radiosurgery, there is an abundance of literature regarding the surgical planning, targeting, and outcomes of these methodologies. To date, there have been no reports of frameless, linear accelerator (LINAC)-based thalomotomies for tremor...
February 24, 2017: Journal of Neurosurgery
https://www.readbyqxmd.com/read/28295837/compromised-hippocampus-striatum-pathway-as-a-potential-imaging-biomarker-of-mild-traumatic-brain-injury-and-posttraumatic-stress-disorder
#19
D Rangaprakash, Gopikrishna Deshpande, Thomas A Daniel, Adam M Goodman, Jennifer L Robinson, Nouha Salibi, Jeffrey S Katz, Thomas S Denney, Michael N Dretsch
OBJECTIVES: Military service members risk acquiring posttraumatic stress disorder (PTSD) and mild-traumatic brain injury (mTBI), with high comorbidity. Owing to overlapping symptomatology in chronic mTBI or postconcussion syndrome (PCS) and PTSD, it is difficult to assess the etiology of a patient's condition without objective measures. Using resting-state functional MRI in a novel framework, we tested the hypothesis that their neural signatures are characterized by functionally hyperconnected brain regions which are less variable over time...
March 15, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28295175/hypothesis-testing-in-functional-linear-models
#20
Yu-Ru Su, Chong-Zhi Di, Li Hsu
Functional data arise frequently in biomedical studies, where it is often of interest to investigate the association between functional predictors and a scalar response variable. While functional linear models (FLM) are widely used to address these questions, hypothesis testing for the functional association in the FLM framework remains challenging. A popular approach to testing the functional effects is through dimension reduction by functional principal component (PC) analysis. However, its power performance depends on the choice of the number of PCs, and is not systematically studied...
March 10, 2017: Biometrics
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