Contrast-enhanced ultrasonography is a feasible technique for quantifying hepatic microvascular perfusion in dogs with extrahepatic congenital portosystemic shunts.

Extrahepatic-congenital portosystemic shunt is a vascular anomaly that connects the portal vein to the systemic circulation and leads to a change in hepatic microvascular perfusion. However, an assessment of hepatic microvascular perfusion is limited by conventional diagnostic modalities. The aim of this prospective, exploratory study was to assess hepatic microvascular perfusion in dogs with extrahepatic-congenital portosystemic shunt using contrast-enhanced ultrasonography (CEUS) using perfluorobutane (Sonazoid® ). A total of 17 dogs were included, eight healthy dogs and nine with extrahepatic-congenital portosystemic shunt. The time-to-peak (TTP), rising time (RT), and rising rate (RR) in the hepatic artery, portal vein, and hepatic parenchyma, as well as the portal vein-to-hepatic parenchyma transit time (ΔHP-PV) measured from time-intensity curve on CEUS were compared between healthy and extrahepatic-congenital portosystemic shunt dogs. The RT of the hepatic artery in extrahepatic-congenital portosystemic shunt dogs was significantly earlier than in healthy dogs (P = 0.0153). The TTP and RT of the hepatic parenchyma were significantly earlier in extrahepatic-congenital portosystemic shunt dogs than in healthy dogs (P = 0.0018 and P = 0.0024, respectively). ΔHP-PV was significantly shorter in extrahepatic-congenital portosystemic shunt dogs than in healthy dogs (P = 0.0018). CEUS effectively revealed changes in hepatic microvascular perfusion including hepatic artery, portal vein, and hepatic parenchyma simultaneously in extrahepatic-congenital portosystemic shunt dogs. Rapid hepatic artery and hepatic parenchyma enhancements may reflect a compensatory increase in hepatic artery blood flow (arterialization) caused by a decrease in portal vein blood flow and may be used as an additional diagnostic test to distinguish extrahepatic-congenital portosystemic shunt dogs from healthy dogs.