Diffusion Imaging in Gray Matter

灰质的扩散成像

• 批准号: 8652499
• 负责人: LAWRENCE R FRANK
• 金额: $ 38.75万
• 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/8652499
• 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; Geometry; 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）由于其对神经组织中扩散各向异性（DA）微观变化的敏感性，作为一种为神经组织结构状态的非侵入性评估提供潜力的方法，引起了基础神经科学研究和临床应用的极大兴趣。然而，标准 DTI 方法，包括其利用一对脉冲场梯度 (sPFG) 的高角分辨率 (HARDI) 扩展，是基于在成像分辨率范围内表现出宏观 DA 的体素成分的存在。这通常是包含白质 (WM) 纤维束的体素的情况，因此 WM 中的 DTI 已成为 DTI 研究和应用的主要焦点。然而，灰质 (GM) 的情况并非如此，灰质在微观上是异质的，但缺乏体素空间尺度上的结构连贯性，无法表现出宏观的 DA。这严重限制了我们利用 MRI 对扩散的敏感性来研究 GM 微观结构的能力，而 GM 是具有重要临床意义的组织。最近，一组基于双脉冲场梯度 (dPFG) 对的新颖 MR 方法已经在理论上进行了研究，并通过简单的实验进行了验证，以表现出对宏观均匀体素中微观 DA 的敏感性。这些研究主要应用于具有微观孔隙的材料，反映了这些方法开发的重点是多孔材料。然而，虽然我们假设这些方法对于 GM 研究具有巨大潜力，但这种组织的巨大复杂性使得 dPFG 方法在 GM 中的研究几乎不可能进行分析。因此，本提案的目标是利用我们最近开发的扩散模拟平台（DiffSim），结合我们最近开发的 dPFG 理论框架，研究 dPFG 方法检测和定量灰质结构参数和变化的能力，并开发在临床上应用这些方法的实验技术。