Duplex ultrasound in the evaluation of portacaval shunts.

The results of ultrasound imaging combined with Doppler studies of blood flow are presented in two patients with surgical portacaval shunts performed for portal hypertension. Duplex scanning proved a quick and noninvasive method of confirming the patency of the anastomoses. The demonstration of appropriate Doppler flow signals across the shunt is the most convincing ultrasound evidence of patency. Portacaval shunts are more amenable to study by ultrasound than more peripheral shunts because the liver can be used as an acoustic window.