[Pre- and post-contrast multiphase helical CT in the diagnosis of hepatic focal nodular hyperplasia].

OBJECTIVE: To analyse the pre- and post-contrast CT findings of liver focal nodular hyperplasia (FNH), so as to improve its diagnostic accuracy. METHODS: Pre-contrast scan and post-contrast tri-phase scan (arterial phase, portal venous phase and delayed phase) were performed in 21 patients with FNH which were proved surgically and pathologically. Transcatheter arterial angiography was performed in 2 patients. RESULTS: On pre-contrast scans, 16 of 21 lesions were hypodense, 5 of 21 were isodense. Twelve of 21 lesions showed punctate, streak and radial scar. On the arterial phase scans, all the lesions were markedly and homogeneously enhanced, except for the central scar. Nine of 21 lesions showed dilated and tortuous arteries at the central or peripheral area. On the portal venous phase scans, focal density was decreased, but still showing hyperdense or slightly hyperdense relative to the normal liver. On the delay phase scans, the lesions changed to isodense or slightly hypodense. Enhanced capsule was observed in 3 patients. On the angiography images, dilated arteries and drainage veins were seen. CONCLUSION: FNH has its special characteristics on the multiphasic helical CT scan. It is of great value in diagnosing the FNH and in choosing the appropriate therapy.