Quantification of liver stiffness and viscosity with SDUV: In vivo animal study

Measurement of liver elasticity (i.e., stiffness) can be as a noninvasive alternative to liver biopsy to stage liver , a condition afflicting hundreds of millions of patients . Quantitative measurement of stiffness (in unit of ) is required because liver fibrosis is a diffuse disease abnormality is not confined to a local region and there is normal background tissue to provide contrast. Shearwave Ultrasound Vibrometry (SDUV) uses shear wave speed measured in tissue at multiple frequencies (typically in the range of hundreds of Hertz) to solve for both tissue elasticity and viscosity. A shear is stimulated within the tissue by an ultrasound push beam monitored by a separate ultrasound detect beam. The phase of the shear wave between two locations along its path is used to calculate shear wave speed within the . An intermittent pulse sequence is developed to facilitate array transducer for both push and detect function. of this pulse sequence is demonstrated by SDUV in porcine liver using both a dual transducer and a modified commercial ultrasound scanner.