Dynamic computed tomography of isodense hepatocellular carcinoma.

Dynamic computed tomography (CT) was performed on 11 patients with isodense hepatocellular carcinoma (hepatoma). Ten consecutive 3 s scans were performed within 30 s following the bolus injection of contrast medium. Except for the diffuse type, isodense hepatoma enhanced strongly in the arterial phase. The degree of enhancement declined in the portal phase. In the case of diffuse hepatoma, fine tumor nodules enhanced slightly, showing mottled patterns intermingled with low and high density areas in one patient. Time-density curves indicated that the tumor density increased rapidly in the arterial phase but decreased in the portal phase, approximating that of the surrounding liver. When CT is used as a screening method to detect hepatoma, the possibility of an isodense tumor should always be kept in mind. Dynamic CT is essential for the detection of isodense hepatoma as well as diffuse, small tumors. If simultaneous multilaminographic CT is available in the future, dynamic CT may be the best method to evaluate a suspected lesion.