Characterization of Skeletal Muscle by MR Elastography

描述（由申请人提供）：本提案的目标有两个：(1)进一步开发和验证一项技术，磁共振弹性成像（MRE），用于定量成像肌肉的机械特性和张力分布；(2)应用该技术对患有四种常见和临床显著肌肉疾病（痉挛、废用性萎缩、肌筋膜疼痛和代谢性肌病）的患者进行体内评估。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绘制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。具体来说，本研究可分为三个具体目的。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。对肌肉进行快速MRE评估的先进技术将继续发展。目的2：用幻体、离体肌肉和有限元建模（FEM）技术验证肌肉特性和张力的MRE评估。有限元分析将使用幻肌和牛肌进行，以更好地将MRE波长结果与肌肉特性、张力和纤维结构的功能联系起来。目的3：体内正常和异常肌肉的研究。MRE技术将在体内应用，以提供已知疾病的异常肌肉的弹性成像。选择用于研究的患者群体在各自的权利上都很重要，并提供了跨肌肉疾病和功能障碍范围的独特信息。研究对象包括新发痉挛性痉挛的个体，包括缺血性、半脑卒中、因固定导致的废用性萎缩、代谢性（甲状腺功能亢进）肌病和肌筋膜疼痛，以确定触发点。这项工作的总体假设是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.