High-angular resolution diffusion MRI for identifying br

用于识别 br 的高角分辨率扩散 MRI

• 批准号: 6828414
• 负责人: Yihong Yang
• 金额: --
• 依托单位: NATIONAL INSTITUTE ON DRUG ABUSE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6828414
• 关键词: bioimaging /biomedical imaging; brain imaging /visualization /scanning; clinical research; corpus callosums; human subject; magnetic resonance imaging; medulla oblongata; method development; noninvasive diagnosis; pons

Diffusion tensor imaging (DTI) has shown promise as a noninvasive tool to investigate brain structures. As an application of DTI, "fiber tracking" techniques have been demonstrated to have the potential to delineate neuronal pathways in the brain and connectivity (and its disruption) in neurological disorders. However, there are challenges in existing DTI and fiber-tracking techniques, such as the problem caused by fiber crossing, in which multiple fiber compartments coexist in an image voxel. In this case, the estimation of the tensor components can be seriously biased, preventing fiber-tracking algorithms from following the actual fiber connectivity in the vicinity. A diffusion model beyond conventional DTI and capable of providing more intravoxel information is essential to overcome this problem. We have developed a new method to map intravoxel structures of white matter, especially fiber crossings, using circular spectrum decomposition based on high-angular resolution measurements of apparent diffusion coefficients (ADC). The basic premise of our method is to determine the ADC values voxelwise on the unit circle spanned by the major and median eigenvectors of the diffusion tensor, and then apply a 1D Fourier-transform onto this circle. The 0th, 2nd, and 4th order harmonic components of the circular spectrum provide effective indices for mean diffusivity, linear fiber, and orthogonal fiber crossing diffusion respectively. A theoretical frame work has been established for the novel diffusion imaging technique. Simulations on a digital phantom demonstrated the effectiveness of the technique to identify fiber intersections. In vivo experiments on normal subjects showed that high 4th-order components (fiber crossings) can be observed in a number of brain regions, including pons, medulla, and areas around corpus callosum. This new technique provides an innovative tool for mapping fiber crossings inside the brain. Information obtained from this technique would be used for improving fiber-tracking techniques and for better delineating neuronal pathways under normal and pathological conditions.

扩散张量成像（DTI）已显示出有望作为研究脑结构的无创工具。作为DTI的应用，已经证明“纤维跟踪”技术有可能描述大脑中的神经元途径，并在神经系统疾病中描述神经元途径（及其破坏）。但是，现有的DTI和纤维跟踪技术存在挑战，例如纤维交叉引起的问题，其中图像体素中的多个纤维室共存。在这种情况下，可以严重偏置张量组件的估计，从而防止纤维跟踪算法遵循附近的实际光纤连通性。传统DTI以外的扩散模型并能够提供更多的弹药信息对于克服此问题至关重要。 我们开发了一种新方法，以基于明显扩散系数（ADC）的高角度分辨率测量值（ADC）基于圆形光谱分解来绘制白质（尤其是纤维交叉口）的射内结构。我们方法的基本前提是确定由扩散张量的主要和中位特征向量跨越的单位圆上的ADC值，然后将1D傅立叶变换应用于该圆圈。圆形光谱的0，第二和第四阶的谐波分量分别为平均扩散率，线性纤维和正交纤维交叉扩散提供了有效指标。为新型扩散成像技术建立了理论框架工作。数字幻影上的模拟证明了该技术识别纤维相交的有效性。对正常受试者的体内实验表明，可以在许多大脑区域（包括POS，髓质和callosum callosum周围的区域）观察到高四阶成分（纤维交叉）。这种新技术提供了一种创新的工具，用于绘制大脑内部的纤维交叉点。从该技术获得的信息将用于改善纤维跟踪技术，并在正常和病理条件下更好地描述神经元途径。