Towards quantitative quasi-static ultrasound elastography using a reference layer for liver imaging application: A preliminary assessment

Abstract

Changes in tissue elasticity are generally correlated with pathological phenomena. For example, diffuse liver disease progressively reduces the elasticity of the liver. Quasi-static elastography is popular in clinical applications to visualize regions with different relative stiffness. However, the limitation of this technique is that it provides only qualitative information. To overcome this, we investigate the use of a calibrated reference layer, sandwiched between the transducer and the tissue surface, to quantitatively image the unknown modulus of the examined tissue. The performance of the method was studied through simulations and experiments on agar-gelatin phantoms having Young's modulus within a range appropriate for the liver application. Furthermore, we explored the translational capability of the proposed method to work with existing commercially-available ultrasound scanners having elastography option. The Young’s modulus value of the phantom estimated from quantitative elastography in simulation and experiment was compared against the corresponding ground-truth modulus value obtained from COMSOL and Universal Testing Machine (UTM) results, respectively. The results obtained for the compressive elastic modulus of the underlying phantom using quasi-static ultrasound elastography was found to be within 6% and 11% in simulation and experiments, respectively, to the corresponding ground-truth values.