MICROMAGNETIC RESONANCE ELASTOGRAPHY

微磁共振弹性成像

基本信息

批准号：
7029644
负责人：
RICHARD L MAGIN
金额：
$ 18.53万
依托单位：
UNIVERSITY OF ILLINOIS AT CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-03-15 至 2008-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7029644
关键词：
articular cartilage bioengineering /biomedical engineering bioimaging /biomedical imaging biomedical equipment development biophysics cartilage disorder elasticity image enhancement magnetic field magnetic resonance imaging mathematical model microradiography miniature biomedical equipment nuclear magnetic resonance spectroscopy tissue engineering

项目摘要

DESCRIPTION (provided by applicant): Magnetic resonance elastography (MRE) is a phase contrast-based MR imaging technique for observing acoustic strain waves propagating in soft materials (e.g., biological tissues: brain, liver, kidney, muscle, as well as gels, polymers and composites). Mechanical shear waves, typically with amplitudes of less than 100 um and frequencies of 100-500 Hz, are induced using either a piezoelectric or speaker coil oscillator directly coupled to the region of interest. By using multiple phase offsets and motion encoding gradients we acquire data that allows the generation of images that depict shear wave motion and the calculation of local values of the tissue viscoelastic properties. Current MRE studies using 1.5 T MRI systems are directed at establishing techniques for quantifying changes in the mechanical properties of tissues associated with developing disease: malignant tumors appear to be stiffer than benign tumors; fibrosis and cirrhosis tend to increase liver stiffness; and articular cartilage softens in developing osteoarthritis. Work to date suggests that MRE may in fact be able to detect both early stage and diffuse disease well before it can be visualized by conventional MRI, ultrasound or X-ray/CT techniques. Recent MRE investigations are increasingly being conducted at higher spatial resolution to establish histological correlations between elasticity maps and tissue structures; such micro MR elastography (uMRE) studies require stronger static fields, higher performance RF coils and gradients, and more compact, higher frequency mechanical actuators. The goal of the proposed exploratory/development project is to design, develop and validate a new high field (11.74 T) fMRE system (2 cm FOV), 5 kHz maximum acoustic frequency that will provide high spatial resolution (less than 100 fm3 voxel) for the measurement of shear moduli up to 2.5 MPa. These capabilities should allow fMRE to be used to evaluate the microstructure of complex materials, tissues such as articular cartilage and the micromechanical properties of tissue engineered constructs. The specific aims are: 1) Design and build a high resolution fMRE system that operates in the 10 mm diameter clear imaging bore available in an 11.74 T NMR spectrometer (500 MHz for proton); 2) Design, construct and evaluate new mechanical actuators suitable for higher frequency (up to 5 kHz) and multi-frequency shear wave excitation; and 3) Apply fMRE to investigate biological, polymer and composite materials at high spatial resolution.

描述（由申请人提供）：磁共振弹性成像（MRE）是一种基于相差的 MR 成像技术，用于观察在软材料（例如生物组织：脑、肝、肾、肌肉以及凝胶、聚合物和复合材料）。使用直接耦合到感兴趣区域的压电或扬声器线圈振荡器来感应机械剪切波，其振幅通常小于 100 um，频率为 100-500 Hz。通过使用多个相位偏移和运动编码梯度，我们获取的数据允许生成描绘剪切波运动的图像并计算组织粘弹性属性的局部值。目前使用 1.5 T MRI 系统的 MRE 研究旨在建立量化与疾病发生相关的组织机械特性变化的技术：恶性肿瘤似乎比良性肿瘤更硬；纤维化和肝硬化往往会增加肝脏硬度；患骨关节炎时关节软骨会软化。迄今为止的工作表明，MRE 实际上可能能够在传统 MRI、超声波或 X 射线/CT 技术可视化之前检测出早期和弥漫性疾病。最近的 MRE 研究越来越多地以更高的空间分辨率进行，以建立弹性图和组织结构之间的组织学相关性；此类微型磁共振弹性成像 (uMRE) 研究需要更强的静态场、更高性能的射频线圈和梯度，以及更紧凑、更高频率的机械致动器。拟议的探索/开发项目的目标是设计、开发和验证新的高场 (11.74 T) fMRE 系统（2 cm FOV），最大声频为 5 kHz，可提供高空间分辨率（小于 100 fm3 体素）用于测量高达 2.5 MPa 的剪切模量。这些功能使得 fMRE 可用于评估复杂材料、关节软骨等组织的微观结构以及组织工程结构的微观机械特性。具体目标是： 1) 设计和构建高分辨率 fMRE 系统，该系统可在 11.74 T NMR 波谱仪（质子为 500 MHz）中提供的 10 mm 直径清晰成像孔中运行； 2）设计、构建和评估适用于更高频率（高达5 kHz）和多频率剪切波激励的新型机械执行器； 3) 应用 fMRE 以高空间分辨率研究生物、聚合物和复合材料。