title: Detection of small hepatocellular carcinoma: intraindividual comparison of gadoxetic acid-enhanced MRI at 3.0 and 1.5 T.
abstract: OBJECTIVE
  To investigate the diagnostic efficacy of gadoxetic acid-enhanced magnetic resonance imaging (MRI) at 3.0 T for the detection of hepatocellular carcinomas (HCC) and compare with that at 1.5 T.
  
  
  METHODS
  Forty patients with 54 HCCs (size range: 0.6-2.0 cm) underwent gadoxetic acid-enhanced MRIs at both 1.5 and 3.0 T with 3 to 8 days interval. The MRIs were compared quantitatively by measuring tumor-liver contrast-to-noise ratio, and qualitatively by evaluating tumor-liver contrast using matched pairs analysis. Diagnostic accuracy and sensitivity were also evaluated by the consensus readings of 2 reviewers using the alternative-free response receiver operator characteristic (ROC) method.
  
  
  RESULTS
  Although the tumor-liver contrast-to-noise ratio for the arterial phase was significantly higher at 3.0 T than at 1.5 T (30.2 ± 21.4 vs. 35.2 ± 22.9; P = 0.04), we found similar values for the hepatocyte phase (38.2 ± 24.6 vs. 38.4 ± 25.3; P = 0.762). Matched pairs analysis indicated that the relative tumor-liver contrast was better in 7 and 9 lesions in the arterial phase and hepatocyte phase at 3.0 T, respectively, than those at 1.5 T. The diagnostic accuracy and sensitivity of 3.0-T imaging [Az, 0.988; 92.6% (n = 50)] were slightly higher than those of 1.5-T imaging [Az, 0.981; 88.9% (n = 48)], but the difference was not statistically significant (P = 0.487).
  
  
  CONCLUSIONS
  Gadoxetic acid-enhanced MRIs at 1.5 and 3.0 T showed similar diagnostic performances for detecting small HCCs. However, there was a tendency toward increased reader confidence for the arterial phase and hepatocyte phase with 3.0 T compared with 1.5 T.
authors.affiliation: Sungkyunkwan University School of Medicine. Department of Radiology, Samsung Medical Center,Sungkyunkwan University School of Medicine, Seoul, South Korea. jmyr@dreamwiz.com
authors.forename: Young Kon
authors.initials: YK
authors.lastname: Kim
authors.forename: Chong Soo
authors.initials: CS
authors.lastname: Kim
authors.forename: Young Min
authors.initials: YM
authors.lastname: Han
authors.forename: Hee Chul
authors.initials: HC
authors.lastname: Yu
authors.forename: Dongil
authors.initials: D
authors.lastname: Choi
mesh_terms: D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA