Characterization of Skeletal Muscle by MR Elastography

描述（申请人提供）：本提案的目标有两个：（1）进一步开发和验证磁共振弹性成像（MRE）技术，用于定量成像肌肉中的机械特性和张力分布，以及（2）应用该技术对患有四种常见且临床上显著的肌肉疾病的患者进行体内评价（痉挛、废用性萎缩、肌筋膜疼痛和代谢性肌病）。 这些研究将采用具有同步运动敏感梯度的磁共振成像序列来映射肌肉中传播的剪切波。 该技术将评估肌肉的机械特性及其张力分布。 具体而言，这项研究可分为三个具体目标。 目标1：优化肌肉评估的MRE采集和分析方法，包括机电驱动器、数据采集技术和图像分析方法。 将继续开发用于非常快速的肌肉MRE评估的先进技术。 目的2：使用体模、离体肌肉和有限元建模（FEM）技术对肌肉特性和张力进行MRE评估。将使用体模和牛肌肉进行有限元分析，以更好地将MRE波长结果与肌肉特性、张力和纤维结构相关联。目的3：研究体内正常和异常肌肉。 MRE技术将在体内应用，以提供具有已知疾病的异常肌肉的弹性成像图像。选择用于研究的患者群体各自都很重要，并提供了肌肉疾病和功能障碍的独特信息。 待研究的组包括缺血性、半球性中风后新发痉挛的个体、由于制动导致的废用性萎缩、代谢性（甲状腺功能亢进）肌病和肌筋膜疼痛以识别触发点。这项工作的总体假设是，这将为基础研究和临床护理带来好处。

DESCRIPTION (provided by applicant): The goal of this proposal is two-fold: (1) to further develop and validate a technology, magnetic resonance elastography (MRE), for quantitatively imaging mechanical properties and tension distribution in muscle and (2) to apply the technique for in vivo evaluation of patients with four common, and clinically significant muscle disorders (spasticity, disuse atrophy, myofascial pain and a metabolic myopathy). These studies will employ a magnetic resonance imaging sequence with synchronous motion-sensitizing gradients to map propagating shear waves in the muscle. The technique will assess the mechanical properties of the muscle and its tension distribution. Specifically, the study can be divided into three specific aims. Aim 1: Optimize MRE methods of acquisition and analysis for the assessment of muscle, including electromechanical drivers, data acquisition techniques, and methods for image analysis. Advanced techniques for very rapid MRE assessment of muscle will continue to be developed. Aim 2: Validate the MRE assessment of muscle properties and tension with phantom, ex-vivo muscle, and Finite Element Modeling (FEM) techniques. Finite Element Analysis will be performed by using both phantom and bovine muscles to better correlate MRE wave-length findings as function of muscle properties, tension and fiber architecture. Aim 3: Study In Vivo Normal and Abnormal Muscle. The MRE technique will be applied in vivo to provide elastographic images of abnormal muscle with known disorders. The patient groups chosen for study are each important in their own right, and furnish unique information across the spectrum of muscular disease and dysfunction. Groups to be studied include individuals with new onset of spasticity following an ischemic, hemispheric stroke, disuse atrophy as a result of immobilization, metabolic (hyperthyroid) myopathy and myofascial pain for trigger point identification. The overall hypothesis of this work is that will bring benefits to both basic research and clinical care.