Objective: To analyze the pre- and post-contrast CT findings of liver focal nodular hyperplasia (FNH) so as to improve their diagnostic accuracy.
Methods: Pre- and post-contrast tri-phase (arterial, portal venous and delayed) scans were performed in 21 patients with FNH proved surgically and pathologically. Transcatheter arterial angiography was performed in 2 patients.
Results: Pre-contrast scans showed hypodensity in 16 patients, isodensity in 5, and punctate, streak and radial scars in 12. Except central scar, all lesions were markedly and homogeneously enhanced in the arterial phase. Nine of the 21 patients showed dilated and tortuous arteries in the central and peripheral areas of the focus. In the portal venous phase, focal density was decreased, though still higher or slightly higher in FNH than in parenchyma. In the delayed phase, the lesions showed isodensity or slight hypodensity. Enhanced capsules were seen in 3 patients. Dilated arteries and drainage veins were seen on angiographic images.
Conclusion: The characteristic manifestations of FNH on multiphasic helical CT scan are of great significance in diagnosing FNH and choosing viable therapy.