Pulsed Doppler and B-mode ultrasound features of interposition meso-caval and porta-caval shunts.

Twenty patients, 13 with meso-caval and 7 with porta-caval shunts were examined with B-mode static and dynamic ultrasound to determine patency of the shunt. Nine of these patients were also examined with pulsed Doppler. In order to confirm the ultrasonic and Doppler findings, angiography was performed in 17 of the 20 patients. Ultrasound examination, which gives anatomic information reflecting changes in flow associated with a shunt, accurately suggested the patency or non-patency of the shunt in all 20 patients. Doppler examination, which gives physiologic information about blood flow and direction of flow, accurately determined patency of the shunt in all 9 cases. Angiography confirmed the ultrasonic and Doppler conclusions in all 17 patients. Ultrasound and Doppler criteria for patency of caval shunts are established. It has been demonstrated that ultrasound examination with pulsed Doppler flow study can reliably determine the patency of porta-systemic shunts. The use of invasive angiographic studies should be reserved for the patients where ultrasound and Doppler examinations suggest shunt occlusion.