Influence of different scanning method on strain ratio measurement:

A phantom study using real‐time tissue elastography

Abstract

Introduction

Strain ratio (SR) measurement using the strain elastography function of an ultrasound diagnostic device can be used to noninvasively measure the stiffness of living tissue by calculating the ratio of strain values between the acoustic coupler and the target material. However, there are no reports on the influence of different scanning methods on SR measurements. Therefore, this study investigated the influence of different scanning methods on SR measurement, using real‐time tissue elastography and a phantom.

Methods

Independent inclusions with stiffness values of 100, 200, and 400 kPa were placed in the phantom and measured using both longitudinal and transverse scanning methods. Measurement error was used to examine the coefficient of variation.

Results

The coefficients of variation of SR, inclusion strain values, and acoustic coupler strain values were similar for both scanning methods with 100 kPa inclusions, but for the 200 and 400 kPa inclusions, the transverse scanning method showed higher values compared with the longitudinal scanning method. Elastography images showed heterogeneous strain distribution in the 200 and 400 kPa inclusions, and the strain distribution was concentrated in the center of the acoustic coupler due to the curvature of the acoustic coupler used in the transverse scanning method.

Conclusion

These results suggest that the SR measurement error increases when SR measurements are performed using the transverse scanning method compared with the longitudinal scanning method for materials with high stiffness.