Tanaka Michitaka, Numano Tomokazu, Habe Tetsushi, Ito Daiki, Maeno Toshiki, Ueki Takamichi, Igarashi Keisuke, Mizuhara Kazuyuki
Department of Radiological Sciences, Faculty of Health Sciences, Tokyo Metropolitan University (Current address: Department of Radiology, Dokkyo Medical University Saitama Medical Center).
Department of Radiological Sciences, Faculty of Health Sciences, Tokyo Metropolitan University.
Nihon Hoshasen Gijutsu Gakkai Zasshi. 2019;75(3):239-246. doi: 10.6009/jjrt.2019_JSRT_75.3.239.
The purpose of this study was to investigate an influence of vibration waveform on magnetic resonance elastography (MRE). MRE is an innovative imaging technique for the non-invasive quantification of the elasticity of soft tissues through the direct visualization of propagating shear waves in vivo using a special phase-contrast magnetic resonance imaging sequence. Since the elasticity of soft tissue calculates from the wavelength of propagating shear waves, it is necessary to propagate sine-wave-shape shear wave at the target soft tissue. However, due to the various factors; i.e. overload of vibration generator, poor contact between imaging object and vibration pad, etc.; it may be difficult to generate a simple sine wave. This work was focused on change vibration waveforms; i.e. square wave, triangle wave, saw-tooth wave; which is induced by the various factors. Phantom experimental results demonstrated that when square and saw-tooth waveforms of 25 Hz vibration frequency, into the phantom, the waveform of propagating wave was not similar to sine waveform. It may influence on the MRE that in case of the waveforms has low frequency and square or saw-tooth like waveforms.
本研究的目的是探讨振动波形对磁共振弹性成像（MRE）的影响。MRE是一种创新的成像技术，通过使用特殊的相位对比磁共振成像序列在体内直接可视化传播的剪切波，对软组织弹性进行无创定量。由于软组织的弹性是根据传播剪切波的波长计算得出的，因此有必要在目标软组织中传播正弦波形的剪切波。然而，由于各种因素，如振动发生器过载、成像对象与振动垫之间接触不良等，可能难以产生简单的正弦波。这项工作聚焦于由各种因素引起的变化振动波形，即方波、三角波、锯齿波。体模实验结果表明，当25Hz振动频率的方波和锯齿波进入体模时，传播波的波形与正弦波形不相似。如果波形具有低频且为方波或锯齿状波形，可能会对MRE产生影响。
