![]() An ultrasound machine (Aplio 400 Canon Medical Systems Corp) was used with a 6-MHz convex probe for CEUS. Therefore, the purpose of this study was to evaluate quantitative assessments of CEUS regarding shunt types, surgical treatments, intrahepatic portal venous branch grades, and portal venous pressure.Īll dogs underwent CEUS as follows: a suspension of perflubutane (Sonazoid Daiichi-Sankyo Corp) was prepared with 2 ml of saline at a concentration of 8 μl/ml. We hypothesized that shunt types, surgical treatments, intrahepatic portal vein branch grades, and portal venous pressure would have an effect on quantitative assessments of dogs with PSS in CEUS. However, past reports in CEUS for canine PSS involved few cases and were insufficient to reveal a relationship between quantitative assessments and intrahepatic portal blood volume and pressure. 6 Thus, hepatic portal and shunt blood volumes depend on cases. Therefore, CEUS may reflect hepatic circulation and be correlated with hepatic portal blood volume and portal pressure.ĭogs with PSS had a large range of SF. These reports have considered that CEUS with PSS reflected a compensatory increase in the hepatic arterial blood flow in the liver to decrease intrahepatic portal blood flow. The second report 16 on CEUS for canine PSS evaluated 9 dogs with extrahepatic PSS using the contrast agent perflubutane in 2019 and showed that quantitative assessments had 100% sensitivity and 75.0% to 87.5% specificity in the diagnosis of PSS. According to this report, the time-intensity curve (TIC) in canine PSS showed that the time to peak was shorter and the inflow slope was steeper than normal dogs. The first report 15 on contrast-enhanced ultrasound (CEUS) for canine PSS evaluated 3 dogs with extrahepatic PSS using the contrast agent perflutren lipid microsphere in 2003. Therefore, less invasive, simpler techniques are desirable for assessing PSS in dogs. However, CTA requires anesthesia, and portal pressure measurement and portal angiography are invasive, requiring laparotomy. Therefore, the preoperative evaluation of shunt type, portal pressure, and intrahepatic portal branch development is clinically important. In one study, 14 the absence of arborizing intrahepatic vasculature on preligation portovenography was correlated with a greater incidence of postoperative complications. 1Ī previous report 13 demonstrated that assessing intrahepatic portal venous branches in portovenography could help determine the degree of shunt attenuation and may predict clinical outcomes postoperatively. ![]() Thus, the intraoperative measurement of portal venous blood pressure is performed as a guide for the degree of attenuation for animals undergoing complete ligation (CL) or partial ligation (PL). 1 The acute occlusion of the shunt vessel can lead to excessively increased portal pressure and may result in multiple acquired shunts or death related with portal hypertension. 8– 12 The degree of shunt attenuation is determined using CTA, operative findings, intraoperative portal venous pressure, and portovenography. Surgery is the treatment of choice for PSS, 1, 7 and surgical attenuation, ameroid constrictor placement (ACP), cellophane banding, and percutaneous transvenous coil embolization (PTCE) are often chosen. The differences of shunt types affect the age at diagnosis, frequency of clinical signs, alkaline phosphatase activities, fasting ammonia concentration, portal vein/aortic ratio, shunt fraction (SF), hepatic arterial blood flow, and portal venous blood flow. 2– 5 The major shunt types include left gastrophrenic shunt (LGP), splenocaval shunt, left gastrocaval shunt (LGC), right gastrocaval shunt (RGC), and left gastroazygos shunt and right gastroazygos shunt. However, recently CT angiography (CTA) has described detailed shunt morphology. 1 Traditionally, extrahepatic PSS was classified simply as portocaval or portoazygos. ![]() Intrahepatic PSS tends to occur in large-breed dogs, whereas extrahepatic PSS is more prevalent in small-breed dogs. Congenital portosystemic shunt (PSS) involves anomalous vessels that allow normal portal blood to pass directly into the systemic circulation 1 and is categorized into extrahepatic and intrahepatic types based on the shunt location.
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