Purpose: To use spinal cord diffusion tensor imaging (DTI) for investigating human cervical funiculi, acquire axial diffusion magnetic resonance imaging (MRI) data with an in-plane resolution sufficient to delineate subquadrants within the spinal cord, obtain corresponding DTI metrics, and assess potential regional differences. Materials and Methods:Healthy volunteers were studied with a 3 T Siemens Trio MRI scanner. DTI data were acquired using a single-shot spin echo EPI sequence. The spatial resolution allowed for the delineation of regions of interest (ROIs) in the ventral, dorsal, and lateral spinal cord funiculi. ROI-based and tractography-based analyses were performed.Results: Significant fractional anisotropy (FA) differences were found between ROIs in the dorsal and ventral funiculi (P ¼ 0.0001), dorsal and lateral funiculi (P ¼ 0.015), and lateral and ventral funiculi (P ¼ 0.0002). Transverse diffusivity was significantly different between ROIs in the ventral and dorsal funiculi (P ¼ 0.003) and the ventral and lateral funiculi (P ¼ 0.004). Tractography-based quantifications revealed DTI parameter regional differences that were generally consistent with the ROI-based analysis. IN THE LAST TWO DECADES basic research on spinal cord injury and pathology has made exciting progress in identifying factors that beneficially influence spinal cord repair and regeneration. In the human, the evaluation of treatment efficacy and spinal cord fiber tract integrity in vivo is limited to behavioral sensorimotor assessments (1-4). Notwithstanding the importance of these assessments there is a growing interest to noninvasively assess human spinal cord white matter micro-architecture in vivo (5-9).Diffusion tensor imaging (DTI) is a noninvasive magnetic resonance technique that is sensitive to the diffusion of water molecules within and across extracellular spaces of tissues. Anisotropic diffusion in the central nervous system (CNS) is caused by barriers to diffusion, such as cell membranes and myelin found in CNS white matter (WM). Higher anisotropy in WM compared to gray matter (GM) has been demonstrated in vivo in both animals and humans and it is generally understood that the primary reason for this higher anisotropy in WM is due to packed axon bundles in various WM regions (10,11). Although WM delineation with DTI is well established in brain, the application of DTI in the spinal cord is more difficult because of its small cross-sectional size, susceptibility artifacts, and motion artifacts from cerebrospinal fluid (CSF) pulsation and respiration.The diameter of the human cervical spinal cord enlargement is %13 mm. In cross-section the spinal cord is typically characterized by the butterfly-shaped GM surrounded by WM. The WM on each side of the spinal cord can be grossly divided into dorsal, lateral, and ventral funiculi. The dorsal funiculus is the spinal cord WM on either side between the dorsal median sulcus and the dorsal root. Similarly, the ventral funiculus is the WM lying on either side between the ventral me...
Here we present a novel pneumatic actuator design for brain magnetic resonance elastography (MRE). Magnetic resonance elastography is a phase contrast technique capable of tracing strain wave propagation and utilizing this information for the calculation of mechanical properties of materials and living tissues. In MRE experiments, the acoustic waves are generated in a synchronized way with respect to image acquisition, using various types of mechanical actuators. The unique feature of the design is its simplicity and flexibility, which allows reconfiguration of the actuator for different applications ranging from in vivo brain MRE to experiments with phantoms. Phantom and in vivo data are presented to demonstrate actuator performance.
Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Tractography of meyer's loop asymmetries NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=21272153&lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=21272153&lang=fr READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions?Contact the NRC Publications Archive team at PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1016/j.eplepsyres.2014.03.006Epilepsy Research, 108, 5, pp. 872-882, 2014 Accepted Manuscript This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A c c e p t e d M a n u s c r i p t ABSTRACT Purpose:The purpose of the current study was to use diffusion tensor imaging (DTI) to conduct tractography of the optic radiations (OR) and its component bundles and to assess both the degree of hemispheric asymmetry and the inter-subject variability ofMeyer's Loop (ML). We hypothesized that there are significant left versus right differences in the anterior extent of ML to the temporal pole (TP) in healthy subjects.Materials and Methods: DTI data were acquired on a 3T Siemens MRI system using a single-shot Spin Echo EPI sequence. The dorsal, central and ML bundles of the OR were tracked and visualized in forty hemispheres of twenty healthy volunteers. The uncinate fasciculus (UF) was also tracked in these subjects so that it could be used as a distinct anatomical reference. Measurements were derived for the distance between ML-TP, ML and the temporal horn (ML-TH) and ML and...
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