Feature of The Week 05/19/2017: Longitudinal Shear Wave Imaging for Elasticity Mapping Using Optical Coherence Elastography
Shear wave measurements for the determination of tissue elastic properties have been used in clinical diagnosis and soft tissue assessment. A shear wave propagates as a transverse wave where vibration is perpendicular to the wave propagation direction. Using shear wave elastography, the shear modulus of a soft tissue can be quantified by tracking the shear wave propagation. In previous measurements, the transverse shear wave propagates perpendicular to the force direction, so the shear modulus in the lateral region of the force can be quantified. However, the shear modulus in the axial region of the force cannot be measured.
Dr. Jiang Zhu, Yusi Miao and other researchers in Prof. Zhongping Chen’s group at the Beckman Laser Institute, the University of California Irvine, visualized a longitudinal shear wave using optical coherence tomography for the quantitative mapping of shear moduli. They demonstrated that a longitudinal shear wave propagated along the vibration direction as a plane wave in the near field of a planar source, and the shear modulus in the axial region of the force was quantified. Furthermore, combination of the transverse shear wave and the longitudinal shear wave provides opportunities for measuring directionally dependent elastic properties in tissues, such as muscles, tendons, etc.
The utilization of the longitudinal shear wave provides good theoretical and practical insights. This is an important improvement to resolve the limited field of view in optical coherence elastography, and provides significant information for the clinical diagnosis of diseases.
For more information see recent Article. Courtesy Jiang Zhu, from University of California at Irvine.