RESUMO
OBJECTIVE: The objective of our study was to prospectively evaluate quantitatively and qualitatively the enhancement patterns of cirrhotic liver tissue and hepatocellular carcinoma (HCC) after administration of the hepatocyte-specific contrast agent gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) on dynamic MRI and to determine the time point of maximum liver-to-lesion contrast. SUBJECTS AND METHODS: Twenty-five patients with HCC in liver cirrhosis underwent 1.5-T MRI. T2-weighted turbo spin-echo and T1-weighted 3D gradient-echo sequences before and between 15 seconds and 20 minutes after the injection of 10 mL of Gd-EOB-DTPA were performed. Signal-to-noise ratios (SNRs) of liver parenchyma and liver-to-lesion contrast-to-noise ratios (CNRs) were calculated and plotted over time. Enhancement patterns of HCC were characterized qualitatively by two radiologists. RESULTS: The SNR of liver parenchyma increased significantly at 15 seconds and 60 seconds after contrast injection and remained stable thereafter. HCC showed positive CNR during the arterial phase and increasingly negative CNR during the further time course (p < 0.05). The maximum absolute CNR was found at 20 minutes after contrast injection. There was no correlation between the degree of enhancement at any time point and tumor grade. On qualitative evaluation, 16 HCCs showed arterial enhancement with early washout, and five showed arterial enhancement with late washout. In the remaining four HCCs, enhancement persisted until 20 minutes. Lesion conspicuity at 20 minutes after contrast injection was at least equal to or higher than it was on the remaining sequences in 19 of the 25 patients. CONCLUSION: After Gd-EOB-DTPA injection, most HCCs showed typical arterial enhancement with early washout. Liver-to-lesion contrast was best at 20 minutes.
