Novel Acquisition Methods for Diffusion MRI

扩散 MRI 的新采集方法

• 批准号: 7379478
• 负责人: ROLAND BAMMER
• 金额: $ 39.07万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7379478
• 关键词: Adult; Algorithms; Area; Award; Budgets; Calendar; Child; Childhood; Clinical; Communities; Complex; Data; Databases; Deposition; Detection; Development; Diagnosis; Diffusion; Diffusion Magnetic Resonance Imaging; Diffusion weighted imaging; Dimensions; Disease; Drops; Enrollment; Entropy; Evaluation; Faculty; Fiber; Figs - dietary; Frequencies; Functional disorder; Funding; Future; Goals; Guidelines; Hand; Head; Image; Immune; Immunity; Individual; Investigation; Left; MRI Scans; Magnetic Resonance Imaging; Maps; Measures; Methods; Metric; Motion; Nature; Neurosciences; Noise; Occupations; Pathologic; Pathway interactions; Patients; Pattern; Phase; Physiological; Positioning Attribute; Posture; Process; Protocols documentation; Protons; Radial; Real-Time Systems; Recording of previous events; Registries; Research; Research Project Grants; Research Proposals; Residual state; Resolution; Rotation; Sample Size; Sampling; Scanning; Scheme; Scientist; Signal Transduction; Slice; Techniques; Testing; Time; United States National Institutes of Health; Update; Upper arm; Variant; Vision; Wages; Weight; Work; clinical application; cost; data space; experience; image reconstruction; improved; insight; magnetic field; millisecond; morphometry; motion sensitivity; novel; peer; prospective; reconstruction; response; simulation; tumor; volunteer; water diffusion; white matter

MOTIVIATION - One of MRI’s inherent biophysical contrast parameters is proton self-diffusion, which can be measured by diffusion-weighted imaging (DWI). A variant, Diffusion Tensor Imaging (DTI), is an MRI method for noninvasive quantitative mapping of anisotropic water diffusion, thereby allowing the non-invasive investigation of white matter (WM) microstructure which might aid in the diagnosis and understanding the pathophysiology of white matter abnormalities and delayed maturation. DTI has been also used extensively for non-invasive tracing of WM pathways in tumor patients and in patients harboring non-focal disease. Unfortunately, DTI still suffers not only from physiologic motion but also from profound technical difficulties that increase with higher magnetic fields; higher magnetic fields on the other hand would offer substantially more signal-to-noise ratio (SNR). One of the major benefactors from motion-compensated DTI at high field would be children because of their smaller head sizes and the higher likelihood of motion. AIMS - The overarching goal of this 2-year research effort is to improve diffusion-weighted multi-shot spiral imaging to create significant improvements in 2D and 3D diffusion tensor imaging. Specifically, the project focuses on improvements for spiral acquisition methods and corresponding reconstruction techniques that reduce distortions, improve immunity to motion, diminish RF deposition, and provide better spatial resolution. Special emphasis is also given on improving image quality of this sequence for pediatric imaging. The specific aims are: (Specific Aim #1) to develop and optimize acquisition and reconstruction methods for real-time spiral diffusion-weighted MRI for 2D and 3D acquisitions; (Specific Aim #2) to define optimal DTI scan parameters for 2D and 3D for adults and children at 3T and 7T for different clinical applications and variants of motion. METHODS - Navigator, (prospective and retrospective) motion and off-resonance correction schemes in concert with augmented parallel imaging reconstruction algorithms will be developed and optimized both in simulations and phantom studies. Healthy children (n=62) and adults (n=30) will be enrolled for extensive testing. Optimal DTI scan parameters for a battery of different clinical questions and variants of motion will be determined by experienced neuroimagers and neuroradiologists. The raw k-space data and high-resolution diffusion tensor data will be added to a registry and can be made available to the public to improve image reconstruction algorithms (e.g. off-resonance correction, parallel imaging, diffusion phase navigation, gridding reconstruction), tensor processing (e.g. studying partial volume effects, crossing fibers, complex tract tracing algorithms) and to provide a normative database for adults and children that can be used in future trials. SIGNIFICANCE –We believe that upon successful completion of this project significant improvements in DTI can be achieved that will improve morphometric assessment and tract tracing in patients harboring various pathologic conditions. Abnormalities in WM and tract projections could provide crucial insights in the pathophysiology of several diseases that attack white matter, and further the understanding of specific neurodevelopmental trajectories of children with and without WM disorders.

动机-MRI固有的生物物理对比参数之一是质子自扩散，可以通过扩散加权成像（DWI）进行测量。扩散张量成像（DTI）是一种用于各向异性水扩散的无创定量映射的MRI方法，从而允许对白色物质（WM）微观结构进行无创研究，这可能有助于诊断和理解白色物质异常和延迟成熟的病理生理学。DTI也被广泛用于肿瘤患者和非病灶性疾病患者的WM通路的非侵入性追踪。不幸的是，DTI仍然不仅受到生理运动的影响，而且还受到随着更高的磁场而增加的深刻的技术困难的影响;另一方面，更高的磁场将提供显著更高的信噪比（SNR）。高场运动补偿DTI的主要受益者之一是儿童，因为他们的头部尺寸较小，运动的可能性较高。AIMS -这项为期2年的研究工作的总体目标是改进弥散加权多激发螺旋成像，以显著改善2D和3D弥散张量成像。具体而言，该项目的重点是改进螺旋采集方法和相应的重建技术，以减少失真，提高抗运动性，减少RF沉积，并提供更好的空间分辨率。 特别强调的是，还提高了图像质量的这个序列的儿科成像。具体目标是：（具体目标#1）开发和优化用于2D和3D采集的实时螺旋弥散加权MRI的采集和重建方法;（具体目标#2）针对不同的临床应用和运动变体，在3 T和7 T下为成人和儿童定义2D和3D的最佳DTI扫描参数。 方法-将在模拟和体模研究中开发并优化导航器、（前瞻性和回顾性）运动和非共振校正方案以及增强并行成像重建算法。健康儿童（n=62）和成人（n=30）将入组进行广泛测试。由经验丰富的神经影像学家和神经放射学家确定一系列不同临床问题和运动变体的最佳DTI扫描参数。原始k空间数据和高分辨率扩散张量数据将被添加到注册表中，并可供公众使用，以改进图像重建算法（例如，非共振校正、并行成像、扩散阶段导航、网格重建）、张量处理（例如，研究部分体积效应，交叉纤维，复杂的束追踪算法），并为成人和儿童提供可用于未来试验的规范数据库。 意义-我们相信，成功完成本项目后，可以实现DTI的显着改善，这将改善形态学评估和跟踪窝藏各种病理条件的患者。对WM和束投射的了解可以为攻击白色物质的几种疾病的病理生理学提供重要的见解，并进一步了解有和没有WM障碍的儿童的特定神经发育轨迹。