Diffusion Tensor Magnetic Resonance Imaging (DTI) allows to decode the mobility of water molecules in cerebral tissue, which is highly directional along myelinated fibers. By integrating the direction of highest water diffusion through the tissue, DTI Tractography enables a non-invasive dissection of brain fiber bundles. As such, this technique is a unique probe for in vivo characterization of white matter architecture. Unraveling the principal brain texture features of preclinical models that are advantageously exploited in experimental neuroscience is crucial to correctly evaluate investigational findings and to correlate them with real clinical scenarios. Although structurally similar to the human brain, the gyrencephalic ovine model has not yet been characterized by a systematic DTI study. Here we present the first in vivo sheep (ovis aries) tractography atlas, where the course of the main white matter fiber bundles of the ovine brain has been reconstructed. In the context of the EU's Horizon EDEN2020 project, in vivo brain MRI protocol for ovine animal models was optimized on a 1.5T scanner. High resolution conventional MRI scans and DTI sequences (b-value = 1,000 s/mm2, 15 directions) were acquired on ten anesthetized sheep o. aries, in order to define the diffusion features of normal adult ovine brain tissue. Topography of the ovine cortex was studied and DTI maps were derived, to perform DTI tractography reconstruction of the corticospinal tract, corpus callosum, fornix, visual pathway, and occipitofrontal fascicle, bilaterally for all the animals. Binary masks of the tracts were then coregistered and reported in the space of a standard stereotaxic ovine reference system, to demonstrate the consistency of the fiber bundles and the minimal inter-subject variability in a unique tractography atlas. Our results determine the feasibility of a protocol to perform in vivo DTI tractography of the sheep, providing a reliable reconstruction and 3D rendering of major ovine fiber tracts underlying different neurological functions. Estimation of fiber directions and interactions would lead to a more comprehensive understanding of the sheep's brain anatomy, potentially exploitable in preclinical experiments, thus representing a precious tool for veterinaries and researchers.
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机译:扩散张量磁共振成像(DTI)允许解码脑组织中水分子的迁移率,这沿髓纤维高度定向。通过将最高水分扩散的方向整合通过组织,DTI牵引能够使脑纤维束的非侵入性解剖。因此,该技术是用于白质架构的体内表征的独特探针。解开有利地利用在实验神经科学中有利的临床型模型的主要脑纹理特征是正确评估调查结果并将它们与真正的临床情景相关联的关键。虽然在结构上类似于人体脑,但椎弓卵泡模型尚未通过系统的DTI研究表征。在这里,我们介绍了第一个体内绵羊(OVI ARIES)牵引图,其中重建了绵延的主要白质纤维束的过程。在欧盟地平线EDEN2020项目的背景下,在1.5T扫描仪上优化了绵延动物模型的体内脑MRI协议。在十个麻醉的绵羊o上获得高分辨率常规MRI扫描和DTI序列(B值= 1,000 s / mm2,15方向)。白羊座,为了定义正常成人卵巢脑组织的扩散特征。研究了绵羊皮质的地形,并得出了DTI地图,进行了DTI牵引性重建皮质脊髓瘤,胼call病,穹窿,视觉途径和枕骨形状,双侧为所有的动物。然后,在标准立体梭形绵羊参考系统的空间中进行了内部掩模并报道了纤维束的一致性,并在独特的牵引图中展示了纤维束的一致性和最小的对象间变异性。我们的结果决定了绵羊的体内DTI牵引装置的协议的可行性,提供了不同神经功能的主要羊纤维的可靠重建和3D渲染。估计光纤方向和互动将导致对绵羊的脑解剖,可能在临床前实验中进行潜在地利用的更全面的了解,从而代表兽医和研究人员的珍贵工具。
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