Imaging of the portal venous system in patients with cirrhosis: MR angiography vs duplex Doppler sonography.

Abstract

To determine the relative performances of MR angiography and duplex Doppler sonography in the evaluation of the portal venous system in patients with portal hypertension, we compared two-dimensional time-of-flight MR angiography and duplex Doppler sonography in 60 sequential patients with cirrhosis. All 60 subsequently underwent liver transplantation. MR imaging and duplex Doppler sonography were performed on the same day, and in all patients the imaging findings were validated at surgical exploration. Five transplantation candidates had surgical portosystemic shunts in situ at the time of imaging. MR images were acquired during breath-holding, and flow in the portal vein was evaluated with presaturation bolus-tracking MR imaging. Sonography included color Doppler and pulsed gated Doppler images of the portal vein. MR angiograms and sonograms were analyzed independently and prospectively for patency of the portal vein, patency of surgical shunts, and grade and distribution of portosystemic collateral vessels. Scores on both imaging techniques were compared by using regression analysis. MR angiograms showed all five cases of portal vein occlusion and all 55 cases of patent portal veins. Sonograms showed three of five cases of portal vein occlusion and 52 of 55 cases of patent portal veins. The techniques concurred in assessing flow direction in 54 (90%) of 60 patients, and both procedures enabled detection of occlusive portal vein thrombus in one patient. We found a significant correlation (p < .001) between the grades of gastric varices detected with MR angiography and surgery but no significant correlation between the grades seen on sonography and found at surgery. Shunt patency in four of five patients and shunt occlusion in one were correctly assessed on MR angiograms, whereas three of these shunts were not visible on sonograms. Our results show that MR angiography is more reliable than duplex Doppler sonography for evaluating the portal venous system in patients with portal hypertension caused by cirrhosis.