Differential diagnosis of early homogeneously enhancing hepatocellular carcinoma and hemangioma by two-phase CT.

Purpose: Our goal was to differentiate between early homogeneously enhancing hepatocellular carcinoma (HCC) and hemangioma by two-phase CT.
Method: Two phase images of 51 HCCs and 28 hemangiomas showing homogeneous high attenuation in the first series (arterial dominant phase) were reviewed. Enhancement patterns of the lesions in the second series (parenchymal phase) were classified as homogeneous high, peripheral high, iso-, and low attenuation. The attenuation values of all and the enhancement values of some (21 HCCs and 18 hemangiomas) in the first series were calculated.
Results: Although low and peripheral high attenuation patterns were seen during the second series only in HCCs (n = 35), which could be used to correctly diagnose HCC, other nonspecific patterns were demonstrated in both HCCs (n = 16) and hemangiomas (n = 28). The attenuation values of 49 of the 51 HCCs and 5 of the 28 hemangiomas were below 130 HU on the first series. The enhancement values of all 21 HCCs and 3 of 18 hemangiomas were below 70 HU. Combining the enhancement patterns with a borderline attenuation value of 130 HU or borderline enhancement value of 70 HU yielded overall accuracies of 94 and 92%, respectively.
Conclusion: The combined criteria (enhancement pattern plus attenuation or enhancement value) were useful for differentiating between early homogeneously enhancing HCCs and hemangiomas.