title: Assessing liver fibrosis: comparison of arterial enhancement fraction and diffusion-weighted imaging.
abstract: OBJECTIVE
  Noninvasive markers have been developed to reduce the need for liver biopsy. The aim of this study was to compare the strength of association of the arterial enhancement fraction (AEF), apparent diffusion coefficient (ADC), and serum biomarkers for staging hepatic fibrosis.
  
  
  METHODS
  Eighty-five patients with chronic liver disease underwent triple-phase contrast-enhanced MRI, used to calculate AEF, and diffusion-weighted MRI (b = 0,750 s/mm(2) ), used to calculate ADC. Hepatic fibrosis was staged according METAVIR criteria. The overall association of the four biomarkers (AEF, ADC, aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio, and aspartate aminotransferase to platelet ratio index [APRI]) was compared using nonparametric tests and receiver operating characteristic (ROC) curve, using histopathologic analysis as the reference standard.
  
  
  RESULTS
  AEF and ADC values differed significantly between histopathologic fibrosis stages. AEF values correlated with fibrosis stage, ADC values correlated negatively with fibrosis stage. Compared with ADC, AEF showed a trend toward an improved capability of discriminating fibrosis stages. A weighted composite score of AEF and ADC had significantly better diagnostic accuracy than ADC alone (P ≤ 0.023). Imaging parameters had a significantly better diagnostic accuracy than AST/ALT ratio or APRI.
  
  
  CONCLUSIONS
  AEF may be able to detect the presence of mild, moderate, and advanced liver fibrosis, and its value is increased with concomitant use of ADC.
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins Hospital, Baltimore, Maryland, USA.
authors.forename: David
authors.initials: D
authors.lastname: Bonekamp
authors.forename: Susanne
authors.initials: S
authors.lastname: Bonekamp
authors.forename: Hsin-You
authors.initials: HY
authors.lastname: Ou
authors.forename: Michael S
authors.initials: MS
authors.lastname: Torbenson
authors.forename: Celia Pamela
authors.initials: CP
authors.lastname: Corona-Villalobos
authors.forename: Esteban
authors.initials: E
authors.lastname: Mezey
authors.forename: Ihab R
authors.initials: IR
authors.lastname: Kamel
mesh_terms: D000328:Adult; D000410:Alanine Transaminase / Q000097:blood*; D001219:Aspartate Aminotransferases / Q000097:blood*; D015415:Biomarkers / Q000097:blood*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005234:Fatty Liver / Q000175:diagnosis / Q000473:pathology; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008099:Liver / Q000473:pathology; D008103:Liver Cirrhosis / Q000145:classification / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase
keywords: apparent diffusion coefficient; arterial enhancement fraction; diffuse liver disease; hepatic fibrosis; quantitative imaging