气动激励装置原型机磁共振弹性成像研究

介绍:磁共振弹性成像是一种无创的对生物组织的生物力学特性进行定量分析的新技术。在诸多外部机械激励方法中,气动激励装置因其磁兼容性好而相对被广泛使用。本研究搭建了一台气动装置原型机并测试了该装置在不同频率和振幅条件下的性能。材料和方法:使用超声方法测试气动激励装置原型机在无负载条件和不同频率和振幅情况下的性能,并在磁共振弹性成像环境测试该原型机在有负载条件下的性能。结果:生物组织的弹性值与外部激励的频率和振幅、生物组织的机械力学特性以及传导管的长度和内径有关。结论:稳定可靠的机械波是磁共振弹性成像中准确可靠地重建组织弹性值的保障,气动激励装置的机械激励参数应根据不同生物组织的特性进行优化,以保证弹性值重建的可靠性。

MR Elastography with A Prototype Pneumatic Driver

Introduction: Magnetic resonance elastography (MRE) is a non-invasive technique to quantitatively assess the mechanical properties of biological tissue. Among multiple actuation methods, pneumatic driver is popularly used due to the advantage of good MR compatibility. In this study we set up a prototype pneumatic driver and investigate its performance under MRE with stimulations of various amplitude-frequency pairs.Materials and Methods: Load-free performance of the driver was tested using ultrasound with stimulations of various amplitude-frequency pairs. Performance with load was tested using MRE with both tissue mimicking phantoms and leg muscle. Results: Frequency and amplitude of the external stimulation, mechanical properties of biological tissue, and the length and the diameter of the transmission tube were all found to affect the elastogram reconstruction. Conclusions: A MR compatible actuating driver generating reliable mechanical stimulation is required to guarantee stable propagating shear waves in tissue. Optimal actuating parameters should be properly determined in the practice of MRE for specific tissue.