Dynamic gadopentetate dimeglumine-enhanced MR imaging of hepatocellular carcinoma

Nineteen patients with 28 histologically proven hepatocellular carcinomas (HCCs) were examined using T1- and T2-weighted spin-echo sequences and dynamic gadopentetate dimeglumine-enhanced magnetic resonance imaging (MRI) performed by fast T1-weighted gradient-echo sequence (100/5/80°) which was performed before and repeatedly (12 sets of images) after intravenous bolus injection of gadopentetate dimeglumine (Gd-DTPA) over a period of 10 min. Enhancement of HCC was heterogeneous in 24 lesions (85.7%). Intra-lesional non-enhancing areas were seen in 18 cases (64%). A late-enhancing pseudocapsule was seen in 12 lesions (42.9%). In addition, two groups were distinguished in the examined HCCs: 16 lesions (57.1%) showed stronger enhancement compared to liver parenchyma with maximum positive lesion-to-liver contrast on the 15-s images, while 12 lesions (42.9%) had an enhancement less than normal liver with a maximum negative contrast on the 15-s images. We conclude that the morphologic features most frequently encountered in HCC on dynamic Gd-DTPA-enhanced MRI are inhomogeneity of enhancement, intra-lesional non-enhancing areas, and relatively late enhancement of a pseudocapsule. Taking the degree of enhancement to be representative of the degree of vascularity, we also conclude that HCC can appear either hypervascular or hypovascular in the early phase of the dynamic study.Correspondence to: B. Hamm