MRI ASSESSMENT OF EXPERIMENTALLY INDUCED TRAUMATIC BRAIN INJURY IN RATS

实验性大鼠脑外伤的 MRI 评估

• 批准号: 6504558
• 负责人: PATRICK KOCHANEK
• 金额: $ 13.47万
• 依托单位: CARNEGIE-MELLON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-30 至 2002-08-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6504558
• 关键词: bioengineering /biomedical engineering; bioimaging /biomedical imaging; biomedical equipment development; biomedical resource; cardiovascular system; magnetic resonance imaging; statistics /biometry; technology /technique

The objective of this project is to develop ultra-fast magnetic resonance imaging techniques and applying them to measuring flow and motion. This is accomplished by: (i) developing ultra-fast imaging for assessment of simple linear (i.e., one directional) flow; (ii) developing ultra-fast imaging for application and assessment of more complex and other rapidly-varying phenomena; (iii) applying ultra-fast imaging techniques developed for Specific Aims (i) and (ii) to the analysis of in-vivo flow and other dynamic in-vivo phenomena, such as heart motion. Rotating Ultra-Fast Imaging Sequence (RUFIS) developed in this Center uses free induction decays (FID) for image reconstruction, and usually the data points at the begining of the FID are not available because of finite recovery times of the hardware. We improved image reconstruction by substituting a Linear Algebra Method (LAM) to reconstruct image profiles directly from FID data. Simulations confirm that the LAM method can accurately reconstruct 1 D projections from oversampled data even when 1/4 of k-space is missing or noise is present. Simulations were also performed to examine and confirm the minimal effects of turbulence and diffusion on signal loss. Using a spin echo-based velocity-encoding preparation sequence followed by RUFIS, quantitative velocity profiles of laminarand turbulent flow have been obtained. Flow has been quantified inside a straightglass phantom, emerging from a stenosis, and traveling through a curved channel. We also used RUFIS to analyze flow boundary reattachment and the effects of secondary flow patterns in curved flow. We also began to adapt RUFIS sequences for in vivo imaging of the rat. RUFIS can be used as an accurate non-invasive technique for distinguishing laminar and turbulent flow, measuring flow velocities, observing eddies, and identifying shear boundary reattachment downstream of a stenosis.

该项目的目标是开发超快磁 共振成像技术并将其应用于测量流量和 运动。 这是通过以下方式实现的：(i) 开发超快成像 用于评估简单线性（即单向）流； (二) 开发超快速成像以用于更多应用和评估 复杂和其他快速变化的现象； (iii) 应用超快 为具体目标 (i) 和 (ii) 开发的成像技术 分析体内流动和其他动态体内现象，例如 心脏运动。 开发旋转超快速成像序列 (RUFIS) 该中心使用自由感应衰减 (FID) 进行图像处理 重建，通常是 FID 开始时的数据点 由于硬件恢复时间有限，因此不可用。 我们通过替换线性代数来改进图像重建 直接从 FID 数据重建图像轮廓的方法 (LAM)。 仿真证实LAM方法可以准确地重建一维 即使 1/4 的 k 空间缺失，也能根据过采样数据进行投影 或存在噪音。 还进行了模拟来检查和 确认湍流和扩散对信号的影响最小 损失。 使用基于自旋回波的速度编码准备序列 其次是 RUFIS，层流的定量速度剖面 已获得湍流。 流量已在内部进行量化 直玻璃模型，从狭窄中出现，并穿过 弯曲的通道。 我们还使用RUFIS来分析流动边界 弯曲中的再附着和二次流型的影响 流动。 我们还开始调整 RUFIS 序列以用于体内成像 老鼠。 RUFIS 可用作精确的非侵入性技术 区分层流和湍流，测量流速， 观察涡流并识别剪切边界重新附着 狭窄的下游。