title: Noninvasive assessment of hepatic fibrosis using gadoxetate-disodium-enhanced 3T MRI.
abstract: BACKGROUND
  Gadoxetate-disodium is a liver-specific MR contrast agent absorbed by hepatocytes via organic anion transporting polypeptide 1B3 and is excreted into the biliary system by multidrug resistance-associated protein 2. It has been suggested that relative parenchymal enhancement on hepatocyte phase image is associated with hepatic function. However, it is not clear whether gadoxetate-disodium-enhanced MRI can be used as a noninvasive fibrosis marker. Thus, the purpose of our study was to evaluate the diagnostic performance of gadoxetate-disodium-enhanced MRI in predicting the hepatic fibrosis stage.
  
  
  METHODS
  A total of 113 patients who had fibrosis staged according to the Batts and Ludwig score were enrolled: F0 (n = 13), F1 (n = 18), F2 (n = 15), F3 (n = 32), and F4 (n = 35). All patients underwent gadoxetate-disodium-enhanced MRI before confirmation by biopsy (n = 67) or surgery (n = 46). For quantitative analysis, the contrast enhancement index (CEI) was calculated by measuring the signal intensity (SI) in liver and paraspinal muscle using a region of interest, as follows: CEI = (liver SI/paraspinal muscle SI) 20 min hepatocyte phase image/(liver SI/paraspinal muscle SI) pre-contrast T1-weighted image. The diagnostic performance was evaluated by the ROC curve, adjusted for the prevalence of each fibrosis stage.
  
  
  RESULTS
  A significant negative correlation was observed between CEI and fibrosis stage (r = -0.545, P < 0.0001). The adjusted AUROC for CEI in the prediction of mild (≥F1), moderate (≥ F2), or severe fibrosis (≥ F3) and liver cirrhosis (F4) was 0.668, 0.703, 0.73, and 0.84, respectively.
  
  
  CONCLUSIONS
  our results demonstrate that quantitative analysis of relative hepatic enhancement using gadoxetate-disodium-enhanced MRI can predict the hepatic fibrosis stage.
authors.affiliation: Department of Radiology, Kyungpook National University Hospital, Republic of Korea.
authors.forename: Yun-Jin
authors.initials: YJ
authors.lastname: Jang
authors.forename: Seung Hyun Cho
authors.initials: SH
authors.lastname: Cho
authors.forename: Ji Hea
authors.initials: JH
authors.lastname: Bae
authors.forename: Gab Chul
authors.initials: GC
authors.lastname: Kim
authors.forename: Hunkyu
authors.initials: H
authors.lastname: Ryeom
authors.forename: Hye Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Kyung-Min
authors.initials: KM
authors.lastname: Shin
authors.forename: Hui Joong
authors.initials: HJ
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D001706:Biopsy; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008099:Liver / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D008103:Liver Cirrhosis / Q000097:blood / Q000473:pathology* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012372:ROC Curve; D012189:Retrospective Studies; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA