OBJECTIVETo analyze the cause of atypical manifestation of hepatocellular carcinoma (HCC) in triple-phase spiral CT enhanced scan.

METHODSTriple-phase spiral CT scan was performed in 75 patients with HCC. The hepatic arterial phase (HAP), portal venous phase (PVP) and delayed phase (DP) images were started at 25 to 30 s, 65 to 70 s and 3 tp 5 min after injection of contrast medium. The contrast enhanced patterns of lesion were observed and analyzed.

RESULTSNinety-two lesions were found in 75 patients. Typical enhanced findings such as hyperdense in HAP and hypodense in PVP and DP was found in 60 of 92 lesions. Atypical enhanced findings were observed in the other 32 lesions. Fourteen of 32 atypical enhanced lesions were hyperdense in HAP and isodense in PVP, of which 8 were seen in liver cirrhosis and 3 in fatty liver. In DP, 10 were hypodense and 4 still isodense. Eight of the 32 lesions were hyperdense both in HAP and PVP, of which 6 were seen in fatty liver. In DP, 3 were isodense and 5 were hypodense. Six of 32 lesions were isodense in HAP which became hypodense in PVP and DP. Four of 32 lesions were all hypodense in HAP, PVP and DP.

CONCLUSIONMultiple atypical enhanced manifestations are present by triple-phase spiral CT scan in HCC. Pattern of blood supply, scanning technique and pathophysiologic status are usually the cause of these findings.