Diffusion Imaging in Gray Matter

灰质的扩散成像

• 批准号: 8476277
• 负责人: LAWRENCE R FRANK
• 金额: $ 37.2万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8476277
• 关键词: Advanced Development; Architecture; Basic Science; Blood capillaries; Brain; Cells; Clinical; Clinical Research; Computer Simulation; Data; Data Set; Development; Diffusion; Diffusion Magnetic Resonance Imaging; Disease; Environment; Exclusion; Exhibits; Fiber; Goals; Human; Image; Imaging Techniques; Investigation; Magnetic Resonance Imaging; Magnetism; Measurement; Measures; Membrane; Methodology; Methods; Microscopic; Modeling; Neurons; Neurosciences Research; Permeability; Physiologic pulse; Physiological; Physiology; Predisposition; Preparation; Rattus; Research; Resolution; Signal Transduction; Solutions; Standardization; Structure; Techniques; Testing; Theoretical Studies; Tissues; Variant; Weight; base; brain tissue; capillary; clinical application; clinical practice; computer generated; density; diffusion anisotropy; gray matter; human subject; imaging modality; innovation; interest; novel; relating to nervous system; research study; simulation; theories; white matter

DESCRIPTION (provided by applicant): Diffusion tensor imaging (DTI), with its sensitivity to microscopic variations in diffusion anisotropy (DA) in neural tissues, has generated great interest in both basic neuroscience research and clinical applications as a method that offers the potential for the non-invasive assessment of the status of neural tissue architecture. However, the standard DTI methodology, including its high angular resolution (HARDI) extensions, which utilizes a single pair of pulsed field gradients (sPFG), are predicated on the existence of voxel compositions that exhibit a macroscopic DA on the scale of the imaging resolution. This is often the case with voxels containing bundles of white matter (WM) fibers and thus DTI in WM has become a major focus of DTI research and applications. However, this is not the case in gray matter (GM) which is microscopically heterogeneous but lacks the structural coherence on the spatial scale of voxels to exhibit macroscopic DA. This has severely limited our ability to utilize the sensitivity of MRI to diffusion in the investigation of GM microstructure, which is a tissue of significant clinical interest. Recently, a novel set of MR methods based upon the double pulsed field gradient (dPFG) pairs have been investigated theoretically and verified in simple experiments to exhibit sensitivity to microscopic DA in voxels that are macroscopically homogeneous. These studies have primarily been applied to materials with microscopic pores, reflecting the focus on porous materials from which these methods developed. However, while we hypothesize that these methods have great potential for the study of GM, the great complexity of this tissue makes investigation of dPFG methods in GM nearly impossible to do analytically. Thus the goal of this proposal is to utilize our recently developed diffusion simulation platform (DiffSim), in conjunction with our recently developed theoretical framework for dPFG, to investigate the ability of dPFG methods to detect and quantitate gray matter architectural parameters and changes, and develop experimental techniques for applying these methods clinically.

描述（由申请人提供）：扩散张量成像（DTI），其对神经组织扩散各向异性（DA）的显微镜变化的敏感性引起了人们对基本神经科学研究和临床应用的极大兴趣，作为一种方法，可为神经组织架构的非侵袭性评估提供潜在的方法。然而，标准DTI方法（包括其高角度分辨率（HARDI）扩展，利用单个脉冲场梯度（SPFG））是基于在成像分辨率的规模上表现出宏观DA的体素组合物的存在。含有白质束（WM）纤维的体素通常是这种情况，因此WM中的DTI已成为DTI研究和应用的主要重点。但是，在微观异质上，灰质（GM）并非如此，但缺乏体素的空间尺度上的结构相干性，无法表现出宏观的DA。这严重限制了我们利用MRI敏感性扩散的能力，该组织是具有重要临床意义的组织。最近，已经对基于双脉冲场梯度（DPFG）对的一组新型MR方法进行了理论上研究并在简单的实验中进行了验证，以表现出对微观DA的敏感性在宏观同质性的体素中。这些研究主要应用于具有微观孔的材料，反映了对这些方法开发的多孔材料的关注。但是，尽管我们假设这些方法具有巨大的GM研究潜力，但该组织的极为复杂性使得对GM中的DPFG方法的研究几乎不可能进行分析。因此，该提案的目的是利用我们最近开发的扩散仿真平台（DIFFSIM）与我们最近开发的DPFG理论框架一起研究DPFG方法的能力，并定量检测和定量灰质物质体系结构参数和变化，并开发用于应用这些方法的实验技术。