Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan; Office of Radiation Technology, Keio University Hospital, Tokyo, Japan.
Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan; Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan.
Magn Reson Imaging. 2022 Oct;92:133-139. doi: 10.1016/j.mri.2022.06.011. Epub 2022 Jun 27.
This study aimed to analyze the time-course of the physical properties of the psoas major muscle (PM) before and after exercise using magnetic resonance elastography (MRE). Muscle stiffness is one of the important properties associated with muscle function. However, there was no research on the stiffness of the PM after exercise. In this study, we investigated time-course changes of the shear modulus of the PM after exercise. Furthermore, T2 values and apparent diffusion coefficient (ADC), as the additional information associated with muscular physical properties, were also measured simultaneously. Healthy young male volunteers were recruited in this study (n = 9) and they were required to perform a hand-to-knee isometric and unilateral exercise (left side). At each time-point before and after exercise, a set of 3 types of MR scans to measure multiple physical properties of the PM [shear modulus (MRE), T2 values, and ADC] were repeatedly taken. On day 1, a single set MR scan was taken before exercise (pre-exercise MR scan), and 6 sets MR scans were taken (5.5 to 38.0 min after exercise). After about 10-min rest (46.0 to 56.0 min after exercise), 4 sets MR scans were taken (57.5 to 77.0 min after exercise). About 10-min rest was taken again (85.0-95.0 min after exercise), 4 sets MR scans were taken (96.5 to 116.0 min after exercise). On days 2 and 7, a single set MR scan (MRE, T2 value, and ADC) was taken on each experimental day. The data were analyzed as relative changes (%) of the given parameters to the pre-exercise values. The results indicated significant decreases in PM shear modulus up to about 30 min after exercise. Then, it gradually increased and showed significant increases at about 100 min after exercise compared to that before exercise. T2 values and ADC showed significant increases up to about 65 min after exercise compared to those before exercise, and then returned to the pre-exercise values. On days 2 and 7, all values showed no significant changes compared to the pre-exercise values. This study is the first to report the time-course of the physical properties of the PM after exercise.
本研究旨在使用磁共振弹性成像（MRE）分析运动前后腰大肌（PM）的物理特性的时程变化。肌肉硬度是与肌肉功能相关的重要特性之一。然而，目前尚无关于运动后 PM 硬度的研究。在本研究中，我们研究了运动后 PM 剪切模量的时程变化。此外，还同时测量了与肌肉物理特性相关的 T2 值和表观扩散系数（ADC）等附加信息。本研究招募了健康的年轻男性志愿者（n=9），要求他们进行手膝等长和单侧运动（左侧）。在运动前和运动后的每个时间点，重复采集一组 3 种用于测量 PM 多种物理特性的 MR 扫描[剪切模量（MRE）、T2 值和 ADC]。在第 1 天，在运动前（运动前 MR 扫描）进行单次 MR 扫描，然后在运动后 5.5 到 38.0 分钟内进行 6 次 MR 扫描。在大约 10 分钟的休息后（运动后 46.0 到 56.0 分钟），进行 4 次 MR 扫描（运动后 57.5 到 77.0 分钟）。再次休息 10 分钟（运动后 85.0-95.0 分钟），进行 4 次 MR 扫描（运动后 96.5 到 116.0 分钟）。在第 2 天和第 7 天，在每个实验日进行单次 MR 扫描（MRE、T2 值和 ADC）。将数据作为相对于运动前值的给定参数的相对变化（%）进行分析。结果表明，运动后 PM 剪切模量明显下降，直至运动后约 30 分钟。然后，它逐渐增加，并在运动后约 100 分钟与运动前相比表现出明显增加。与运动前相比，T2 值和 ADC 在运动后约 65 分钟内显著增加，然后恢复到运动前的值。在第 2 天和第 7 天，与运动前相比，所有值均无明显变化。本研究首次报道了运动后 PM 物理特性的时程变化。
