Drainage patterns of the cholecystic vein evaluated by power Doppler imaging

Power Doppler imaging (PDI) is a new technique that enhances detection of low-velocity blood flow. We used this modality to assess gallbladder vasculature, especially drainage pattern and flow analysis of the cholecystic vein. The power Doppler equipment used in this study was the Acuson Sequoia 512 system (Mountain View, California). Subjects were 27 patients with acute cholecystitis, 9 with gallbladder polyps, 7 with adenomyomatosis, 6 with gallstones, 2 with gallbladder cancer, 8 with liver cirrhosis, 7 with fatty liver, 4 with portal occlusion resulting from tumor thrombus, and 2 with anomalous arrangement of the pancreaticobiliary ductal system. Ninety vessels in 72 individuals were evaluated with PDI. Continuous wave-form signals (cystic veins) were delineated at the body of the gallbladder in 67% of 72 cases (90 vessels) and in the fundus in 22%. Vessels communicating with the cystic vein (drainage vessel) were then analyzed in 78 veins. The drainage vessel was assessed to be a portal branch of segment 5 of the liver (P 5) in 59%, a middle hepatic vein (MHV) in 38%, and the PV trunk in 3%. The cystic vein from the body drained into the P 5 in 74% and the fundus drained into the MHV in 75%. On fast Fourier transformation analysis of the cystic venous flow, estimated maximal velocity (V_max) was relatively high in patients with acute cholecystitis, gallbladder cancer and portal occlusion. Interestingly, the focal spared area in the fatty liver appeared to be perfused with cystic veins, in addition to having reduced portal blood flow. We conclude that power Doppler imaging may hold promise for assessing drainage pattern of the cystic vein.