The usefulness of gadoxetic acid-enhanced dynamic magnetic resonance imaging in hepatocellular carcinoma: toward improved staging.

PURPOSE: This study was designed to evaluate the usefulness of gadoxetic acid-enhanced dynamic magnetic resonance imaging (MRI) in staging hepatocellular carcinoma (HCC).
METHODS: This study was approved by the institutional review board of our institution. Two investigators independently and retrospectively reviewed dynamic computed tomography (CT) and gadoxetic acid-enhanced dynamic MRI obtained from July to September 2011 in 195 patients with HCC (158 men, 37 women; mean age, 57.1 years). The diagnostic performances of dynamic CT and MRI were evaluated. Barcelona Clinic Liver Cancer (BCLC) stages were determined before and after gadoxetic acid-enhanced dynamic MRI and according to final diagnosis. Change in BCLC stage was evaluated after adding gadoxetic acid-enhanced dynamic MRI to dynamic CT. Diagnostic performance and BCLC staging between the two modalities were compared using the McNemar test.
RESULTS: Final BCLC stage was classified as stage 0 in 25 patients (12.8%), A in 118 (60.5%), B in 33 (16.9%), C in 17 (8.7%), and D in 2 (1.0%). Compared with dynamic CT, gadoxetic acid-enhanced dynamic MRI showed significantly greater sensitivity (90.6% [203/224] vs. 79.5 % [178/224]; P < 0.0001) and significantly more accurate BCLC staging (92.8% [181/195] vs. 80.5% [157/195]; P < 0.0001). BCLC stage was changed correctly after gadoxetic acid-enhanced dynamic MRI in 13.8% (27/195) patients showing differences between CT and final BCLC stages.
CONCLUSIONS: Gadoxetic acid-enhanced dynamic MRI provided important additional information compared with dynamic CT during initial staging workups in patients with HCC. Gadoxetic acid-enhanced dynamic MRI showed higher diagnostic performance and more accurate BCLC staging than dynamic CT.