Feasibility of Shear Wave Elastography and Dispersion Imaging in the Evaluation of Hepatic and Renal Congestion in Dogs.

When heart disease progresses to heart failure, congestion develops in various organs, including the liver and kidneys. Although organ congestion is a critical factor closely associated with the prognosis of heart failure, a simple and quantitative method for evaluating the degree of organ congestion has not yet been established. Two-dimensional shear wave elastography (2D-SWE) is a noninvasive ultrasound technique that can estimate tissue stiffness by measuring shear wave speed (SWS), an index of tissue viscoelasticity, and dispersion slope (DS), which reflects tissue viscosity alone. This study aimed to assess the utility of SWS and DS in evaluating hepatic and renal congestion in transfused dogs by performing 2D-SWE before and after blood transfusion. The ratio of the short diameter (SD) to the long diameter (LD) of the caudal vena cava (CVC SD/LD) was used as an index of congestion. Twenty transfusions were administered to 17 dogs. After transfusion, both the liver and kidney SWS and DS, along with CVC SD/LD, significantly increased. A moderate positive correlation was observed between the CVC SD/LD and liver SWS (r = 0.781, p < 0.01) and kidney SWS (r = 0.744, p < 0.01). Conversely, a strong positive correlation was found between the CVC SD/LD and liver DS (r = 0.900, p < 0.01) and kidney DS (r = 0.850, p < 0.01). These findings suggest that 2D-SWE may be a valuable tool for assessing liver and kidney congestion, with DS potentially serving as a reliable indicator of congestion.