Background: Shear wave elastography (SWE) is an ultrasound technique, which measures shear wave speed (SWS), an index of viscoelasticity, and dispersion slope (DS), an index of viscosity. In the liver, fibrosis elevates elasticity, while congestion or inflammation elevates viscosity. Hypothesis/
Objectives: To investigate the usefulness of SWE to evaluate inflammation and fibrosis in dogs with hepatic disease. Animals: Forty client-owned dogs which underwent liver biopsy.
Methods: In this cross-sectional prospective study, SWS (m/s) and DS [(m/s)/Hz] were measured using SWE in dogs that underwent surgical or laparoscopic liver biopsy. Stages of inflammation and fibrosis were scored according to the WSAVA diagnostic criteria (Inflammation: A score0-5, Fibrosis: F score0-4). Dogs were classified into the following three groups based on A and F scores: Control Group (A0 F0), Inflammation Group (A≥1 F≤1), Fibrosis Group (F≥2).
Results: SWS was significantly higher in Fibrosis Group (1.93, IQR:1.83-2.21) than Control Group (1.36, IQR:1.32-1.39) and Inflammation Group (1.45, IQR:1.34-1.63) but there was no difference between Control and Inflammation Group. DS was significantly higher in Inflammation Group (14.80, IQR:14.40-16.50) and Fibrosis Group (16.50, IQR:14.50-17.20) than Control Group (12.25, IQR:11.95-13.18). DS (AUC=0.992) was superior to SWS (AUC=0.717) in discriminating between Control Group and Inflammation Group. SWS strongly correlated with F score (ρ=0.83) and moderately with A score (ρ=0.52). Whereas DS strongly correlated with A score (ρ=0.88) and moderately with F score (ρ=0.58). Conclusions and clinical importance: Elevated SWS reflects fibrosis and elevated DS reflects inflammation. SWE can be useful in assessing inflammation and fibrosis for dogs with hepatic disease.
