Hepatic nodules with early enhancement during computed tomography portography: Report of six cases

Aim: To study the clinicopathologic characteristics of hepatic nodular lesions with high attenuation (increased portal blood flow) compared with surrounding hepatic parenchyma on computed tomography (CT) during arterial portography (CTAP). Methods: For six lesions found in six patients demonstrated as a high-attenuated mass by CTAP, CT during hepatic arteriography (CTHA; n = 3 patients), digital subtraction hepatic arteriography (n = 6) and conventional helical CT (n = 6) were evaluated retrospectively and compared with histopathologic findings (n = 4). Pathologic diagnosis was atypical adenomatous hyperplasia, nodule-in-nodule hepatocellular carcinoma (HCC) in one resected lesion each and overt HCC in two biopsied lesions. Two patients did not undergo any therapy and were followed up. Results: The average size of lesions was 2.2 cm (range 1.2-3.5 cm). The CTAP revealed high attenuation in all six lesions; entirely within the lesion (n = 4 lesions) or peripherally with a central low attenuation (n = 2). In contrast, CTHA showed low attenuated lesions; entirely within the mass (n = 2) or peripherally with a central high-attenuated spot (n = 1). Hepatic arteriogram revealed only two hypervascular lesions; entirely and partially in one each. In the arterial phase of helical CT, all but one lesion were iso- or hypo-attenuated. In two patients who were followed up to 39 and 55 months without therapy, neither tumor growth nor hemodynamic change of the lesion was recognized on CT. Conclusions: Even though the incidence of hepatic nodular lesions demonstrated as high attenuating on CTAP is low, all but one lesion in the current series showed iso- or hypo-attenuation on CTHA and/or helical CT, suggesting the hemodynamics are reciprocal between CTAP and CTHA. One exceptional lesion that showed high attenuation on both CTAP and conventional CT was pathologically advanced HCC. Based on the follow-up study of two untreated patients, this kind of lesion with high attenuation on CTAP seems to grow slowly.