Diffraction-biased shear wave fields generated with longitudinal magnetic resonance elastography drivers
- 作者：Meng Yin ; Olivier Rouviè ; re ; Kevin J. Glaser ; Richard L. Ehman
- 关键词：Magnetic resonance elastography ; Longitudinal MRE driver ; Shear wave ; Shear stiffness ; Diffraction
- 刊名：Magnetic Resonance Imaging
- 出版年：2008
- 期刊代码：188_0730725x
- 类别：med
- 出版时间：July 2008
- 卷：26
- 期：6
- 页码：770-780
- 文件大小：915 K
摘要
Magnetic resonance elastography (MRE) is a technique for quantifying the acoustic response of biological tissues to propagating waves applied at low frequencies in order to evaluate mechanical properties. Application-specific MRE drivers are typically required to effectively deliver shear waves within the tissue of interest. Surface MRE drivers with transversely oriented vibrations have often been used to directly generate shear waves. These drivers may have disadvantages in certain applications, such as poor penetration depth and inflexible orientation. Therefore, surface MRE drivers with longitudinally oriented vibrations are used in some situations. The purpose of this work was to investigate and optimize a longitudinal driver system for MRE applications. A cone-like hemispherical distribution of shear waves being generated by these drivers and the wave propagation being governed by diffraction in the near field are shown. Using MRE visualization of the vector displacement field, we studied the properties of the shear wave field created by longitudinal MRE drivers of various sizes to identify optimum shear wave imaging planes. The results offer insights and improvements in both experimental design and imaging plane selection for 2-D MRE data acquisition.