title: Equilibrium contrast-enhanced CT imaging to evaluate hepatic fibrosis: initial validation by comparison with histopathologic sampling.
abstract: OBJECTIVE
  To prospectively evaluate hepatic extracellular volume (ECV) fraction measurement at equilibrium computed tomographic (CT) imaging compared with both fibrosis quantified with histologic analysis and the enhanced liver fibrosis panel (ELF) in a cohort of patients with chronic hepatitis.
  
  
  METHODS
  This prospective study was approved by the regional ethics committee. All patients gave fully informed written consent. Forty patients with a clinical indication for liver biopsy were prospectively recruited for liver ECV quantitation at equilibrium CT imaging. Biopsy samples underwent digital image analysis and assessment of collagen content expressed as the collagen-proportionate area (CPA). Spearman correlation was used to evaluate association between ECV, ELF, and CPA. Multiple regression analysis was used to test prediction of CPA by a model that combined ECV and ELF. ECV, ELF score, and CPA were compared with Ishak stage by using the Kruskal-Wallis test.
  
  
  RESULTS
  Complete ECV, ELF, and CPA were available in 33 patients. Liver ECV, CPA, and ELF had a median of 0.26 (interquartile range [IQR], 0.24-0.29), 5.0 (IQR, 3.0-15.0), and 9.71 (IQR, 8.14-10.92), respectively. Hepatic ECV demonstrated good association with CPA (r = 0.64; P < .001) and ELF score (r = 0.38; P < .027), with no significant difference in strength of correlation (P = .177). The regression model that combined ELF and ECV achieved good prediction of CPA (R(2) = 0.67; P < .001). Significant variation in ECV and ELF was seen between fibrosis stage groups.
  
  
  CONCLUSIONS
  Hepatic ECV measured with equilibrium CT imaging is associated with biopsy-derived CPA and serum ELF-validated markers of liver fibrosis. This suggests that equilibrium CT imaging can quantify diffuse fibrosis in chronic liver disease.
authors.affiliation: From the UCL Centre for Medical Imaging (S.B., S.P., S.A.T.), UCL Institute for Liver and Digestive Health, Division of Medicine (W.M.R., R.J.), and UCL Institute for Cardiovascular Science (J.C.M.), University College London, Gower St, London WC1E 6BT, England; and Department of Cellular Pathology, UCL Medical School, Royal Free Campus, London, England (A.R.H., A.D.).
authors.forename: Steve
authors.initials: S
authors.lastname: Bandula
authors.forename: Shonit
authors.initials: S
authors.lastname: Punwani
authors.forename: William M
authors.initials: WM
authors.lastname: Rosenberg
authors.forename: Rajiv
authors.initials: R
authors.lastname: Jalan
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Hall
authors.forename: Amar
authors.initials: A
authors.lastname: Dhillon
authors.forename: James C
authors.initials: JC
authors.lastname: Moon
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Taylor
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D003287:Contrast Media; D005260:Female; D006801:Humans; D007472:Iohexol; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol