Ito Daiki, Numano Tomokazu, Mizuhara Kazuyuki, Takamoto Kouichi, Onishi Takaaki, Nishijo Hisao
Department of Radiological Science, Graduate School of Human Health Science, Tokyo Metropolitan University.
Nihon Hoshasen Gijutsu Gakkai Zasshi. 2016;72(12):1222-1229. doi: 10.6009/jjrt.2016_JSRT_72.12.1222.
Palpation is a standard clinical tool to diagnose abnormal stiffness changes in soft tissues. However, it is difficult to palpate the supraspinatus muscle because it locates under the trapezius muscle. The magnetic resonance elastography (MRE) uses harmonic mechanical excitation to quantitatively measure the stiffness (shear modulus) of both the superficial and deep tissues. The purpose of this study was to build a vibration system for applying the MRE to the supraspinatus muscle. In this study, a power amplifier and a pneumatic pressure generator were used to supply vibrations to a vibration pad. Six healthy volunteers underwent MRE. We investigated the effects of position (the head of the humerus and the trapezius muscle) of the vibration pad on the patterns of wave propagation (wave image). When the vibration pad was placed in the trapezius muscle, the wave images represented clear wave propagation. On the other hand, when the vibration pad was placed in the head of the humerus, the wave images represented unclear wave propagation. This result might be caused by wave interferences resulting from the vibrations from bones and an intramuscular tendon of the supraspinatus muscle. The mean shear modulus also was 8.12 ± 1.83 (mean ± SD) kPa, when the vibration pad was placed in the trapezius muscle. Our results demonstrated that the vibration pad should be placed in the trapezius muscle in the MRE of the supraspinatus muscle.
触诊是诊断软组织异常僵硬变化的标准临床工具。然而，由于冈上肌位于斜方肌下方，很难对其进行触诊。磁共振弹性成像（MRE）利用谐波机械激励来定量测量浅表和深部组织的硬度（剪切模量）。本研究的目的是构建一个将MRE应用于冈上肌的振动系统。在本研究中，使用功率放大器和气压发生器向振动垫提供振动。六名健康志愿者接受了MRE检查。我们研究了振动垫的位置（肱骨头部和斜方肌）对波传播模式（波图像）的影响。当振动垫置于斜方肌中时，波图像显示出清晰的波传播。另一方面，当振动垫置于肱骨头部时，波图像显示出不清晰的波传播。这一结果可能是由骨骼和冈上肌肌内肌腱的振动产生的波干扰所致。当振动垫置于斜方肌中时，平均剪切模量也为8.12±1.83（平均值±标准差）kPa。我们的结果表明，在对冈上肌进行MRE检查时，振动垫应置于斜方肌中。
