AIM:To recognize the characteristic findings of non-pathologic perfusion defects with CT arterial portography (CTAP) and nonpathologic enhancement found in CT hepatic arteriography (CTHA).METHONDS:The manifestations of nonpathologic perfusion defects with CTAP and non pathologic enhancement found in CTHA were analyzed in 50 patients with primary hepatocellular carcinoma.RESULTS:The false-positive rate of perfusion defects detected in CTAP was 15.1% The shapes of perfusion defects were peripheral wedge, small, round, and patchy. The occurrence rate of non-pathologic enhancement found in CTHA was 22.0%. The shapes of non-pathologic enhancement were small, round, irregular, and wedge.CONCLUSION:There was high frequency of non-pathologic perfusion defects detected with CTAP and non-pathologic enhancement found in CTHA. The simultaneous use of both procedures may help decrease the false-positive rate, and increase the veracity of diagnosis for hepatocellular carcinoma.