The usefulness of gadoxetic acid-enhanced dynamic magnetic resonance imaging in hepatocellular carcinoma: toward improved staging. 
This study was designed to evaluate the usefulness of gadoxetic acid-enhanced dynamic magnetic resonance imaging (MRI) in staging hepatocellular carcinoma (HCC).  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.  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.  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.