Characterization of involuntary spontaneous focal muscle activity by means of motion-sensitive magnetic resonance imaging and automated post-processing of data

在静止骨骼肌的一系列扩散敏感单次激发磁共振图像的单个图像中，即使在健康受试者中也经常发生明显的区域限制信号空白。这些信号空洞在一系列测量过程中显示出不同的几何形状和定位，其中一些肌肉群比其他肌肉群更频繁地受到影响。在同时导出的表面肌电图（sEMG）中，信号空洞与弱电活动具有高度相关性。短的不自主的局灶性收缩，在显微镜下不影响所有的肌肉纤维平等，从而导致不连贯的运动模式，被认为是信号空白的原因。微观尺度上的相对运动引起像素的信号分量的失相（像真实的扩散运动），并导致在扩散敏感图像中观察到的信号空隙。信号空白的模式表明运动神经元的个体激活的自发活动。该研究项目旨在进一步表征自发肌肉活动的现象，基于受资助的初始DFG提案的发现，在不同年龄和性别的健康志愿者群体和特定患者群体中。将使用表面肌电图（sEMG）方法和MRI图像采集的sEMG触发的并行应用程序来更精确地表征机械反应的过程，该过程与电活动相比延迟。此外，新方法的价值将通过与临床建立的诊断程序进行比较来研究。在研究自发性肌肉运动（肌束震颤）的神经学诊断中，有时难以检测更深肌肉层的超声方法以及使用针电极的肌电图检查是可用的。虽然后一种方法有点侵入性，但它可以揭示运动神经元疾病的特定变化。在该项目的第一阶段，MRI序列和评估程序将进行调整和优化，以应用于与神经肌肉疾病相关的肌肉区域。进一步发展的组合sEMG-MRI的调查方面的鲁棒性的检测算法的前瞻性图像将提供一个详细的洞察力的相互关系的电气和机械活动。在该项目的第二阶段，将对健康志愿者和特定患者组进行不同临床确定方法（肌肉超声和针肌电图）的系统研究。这将允许通过评价MRI方法与既定程序相比的优势和劣势，对MRI方法的结果进行更好的分类。

In single images of series of diffusion-sensitive single-shot magnetic resonance images of resting skeletal muscles, distinct regionally limited signal voids often occur even in healthy subjects. These signal voids show different geometry and localization in the course of a series of measurements, with some muscle groups being affected more frequently than others. The signal voids show a high correlation to weak electrical activities in the simultaneously derived surface electromyography (sEMG). Short involuntary focal contractions, which microscopically do not affect all muscle fibers equally and thus lead to incoherent movement patterns, are assumed to be the cause of the signal voids. The relative movements on the microscopic scale induce a dephasing of the signal components of the pixels (like real diffusion movements) and lead to the observed signal voids in diffusion-sensitive images. The pattern of signal voids indicates spontaneous activities with individual activations of motor neurons. This research project aims to further characterize the phenomenon of spontaneous muscle activity, based on the findings of the funded initial DFG proposal, in different age and gender groups of healthy volunteers and in specific patient groups. A parallel application of surface electromyographic (sEMG) methods and sEMG triggering of the acquisition of MRI images will be used to characterize more precisely the course of the mechanical reaction, which is delayed compared to the electrical activity. Furthermore, the value of the new method will be investigated by comparing it with clinically established diagnostic procedures. In neurological diagnostics for the investigation of spontaneous muscular movements (fasciculations), sonographic methods, which are sometimes difficult to detect deeper muscle layers, as well as electromyographic examinations with needle electrodes are available. Although the latter method is somewhat invasive, it can reveal specific changes in motor neuron diseases. In the first phase of the project, MRI sequences and evaluation procedures will be adapted and optimized for applications in muscle areas that are relevant for neuromuscular diseases. A further development of the combined sEMG-MRI investigation with regard to the robustness of the detection algorithms for prospective images will provide a detailed insight into the interrelationships of electrical and mechanical activities. In the second phase of the project, systematic investigations with different clinically established methods (muscle sonography and needle electromyography) will be performed on healthy volunteers and specific patient groups. This will allow a better classification of the results of the MRI method by evaluation of its strengths and weaknesses compared to established procedures.