Duplex ultrasonography as a noninvasive technique for assessing portal hemodynamics.

Duplex ultrasonography was evaluated as a noninvasive, quantitative technique of assessing portal hemodynamic characteristics. Portal blood flow measured by duplex ultrasonography was significantly decreased in patients with portal hypertension (450 +/- 86 ml/min) compared with control subjects (874 +/- 44 ml/min; p less than 0.001). Quantitative assessment of portal blood flow by duplex ultrasound correlated with qualitative portal perfusion grading by angiography, and direction of flow was always accurately determined by duplex ultrasonography. Although the angiographic portal perfusion grade did not change significantly in the early postoperative period after distal splenorenal shunting, a decrease in mean portal blood flow of more than 50 percent was documented by duplex ultrasonography. Duplex ultrasonography appears to be at least as accurate as angiography and is an acceptable alternative to this more invasive technique for the longitudinal assessment of portal blood flow.