The cause of nontumorous defects of portal perfusion in the hepatic hilum revealed by CT during arterial portography

OBJECTIVE. We investigated the cause of nontumorous defects of portal perfu sion in the hepatic hilum revealed by CT during arterial portography (CTAP) . MATERIALS AND METHODS. One hundred sixty patients who simultaneously underw ent CTAP and CT during hepatic arteriography of the common hepatic artery f ormed the basis of our study. The frequency, site, and shape of nontumorous defects of portal perfusion in the hepatic hilum on CTAP and the findings on CT during hepatic arteriography were determined. In 13 patients in whom nontumorous portal perfusion defects were observed on CTAP, CT was performe d during selective angiography via the gastric artery, pancreaticoduodenal artery, or both. RESULTS. Nontumorous defects of portal perfusion were detected in 49 region s in 33 of the 160 patients (dorsum of segment IV, n = 30; dorsum of the la teral segment, n = 11; segment I, n = 8). Of the 33 patients, 16 had two de fects each. Of the 49 nontumorous defects of portal perfusion, 38 showed en hancement on CT during hepatic arteriography. In the 13 patients who underw ent CT during selective arteriography, enhancement due to nonportal venous inflow was seen in 16 of the 19 areas of decreased nontumorous portal perfu sion (dorsum of segment IV: nine of 11; dorsum of the lateral segment, four of five; segment I, three of three). CONCLUSION. The main cause of nontumorous defects of portal perfusion in th e hepatic hilum revealed by CTAP is decreased portal inflow due to nonporta l supply via the parabiliary venous system. Thus, such lesions were also en hanced at a high frequency on CT during hepatic arteriography.