title: MR elastography for the assessment of hepatic fibrosis in patients with chronic hepatitis B infection: does histologic necroinflammation influence the measurement of hepatic stiffness?
abstract: OBJECTIVE
  To determine the diagnostic performance of magnetic resonance (MR) elastography for the staging of hepatic fibrosis and to evaluate the influence of necroinflammation on hepatic stiffness in patients with chronic hepatitis B virus (HBV) infection by using histopathologic findings as the reference standard.
  
  
  METHODS
  One hundred thirteen consecutive patients with chronic HBV infection were recruited prospectively in this institutional review board-approved study after providing written informed consent between March 2012 and October 2013. The stiffness measurements were obtained by using two-dimensional gradient-echo MR elastography with a 3.0-T MR system. The METAVIR scoring system was used for the assessment of fibrosis ("F" stage) and necroinflammation ("A" grade). The predictive ability of MR elastography was evaluated by using the receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC). Multiple linear regression analyses were conducted to determine the relationship between hepatic stiffness and the variables that showed a significant association in the univariate analysis or those that were of interest for comparison with earlier work (histologic scores, sex, age, aspartate aminotransferase level, and aspartate aminotransferase/alanine aminotransferase ratio).
  
  
  RESULTS
  MR elastography showed excellent performance for characterization of ≥ F1, ≥ F2, ≥ F3, and F4 findings, with AUC values of 0.961, 0.986, 1.000, and 0.998, respectively. It showed a moderate capability for evaluation of necroinflammatory activity of ≥ A1, ≥ A2, and A3 (AUC = 0.806, 0.834, and 0.906, respectively). Multiple linear regression analysis showed that fibrosis, necroinflammation, and sex were independently associated with hepatic stiffness (β = 0.799, 0.277, and 0.070, respectively; P < .05). For pairwise comparisons, log-transformed hepatic stiffness showed no difference between (a) groups F0/A2-3 and F1/A0-1 and (b) groups F1/A2-3 and F2/A0-1 (P > .99 and P = .486, respectively).
  
  
  CONCLUSIONS
  MR elastography demonstrated excellent performance for distinguishing the stages of hepatic fibrosis in patients with chronic HBV infection. For hepatic tissue with ≤ F2 fibrosis, necroinflammation can account for a substantial fraction of the increase in hepatic stiffness.
authors.affiliation: From the Departments of Radiology (Y.S., Q.G., Q.L., J.L.) and Infectious Disease (F.X.), Shengjing Hospital, China Medical University, 36 Sanhao St, Heping District, Shenyang 110004, People's Republic of China; and Departments of Biomedical Engineering (B.D.) and Radiology (K.J.G., R.L.E.), Mayo Clinic, Rochester, Minn.
authors.forename: Yu
authors.initials: Y
authors.lastname: Shi
authors.forename: Qiyong
authors.initials: Q
authors.lastname: Guo
authors.forename: Fei
authors.initials: F
authors.lastname: Xia
authors.forename: Bogdan
authors.initials: B
authors.lastname: Dzyubak
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Glaser
authors.forename: Qiuju
authors.initials: Q
authors.lastname: Li
authors.forename: Jiahui
authors.initials: J
authors.lastname: Li
authors.forename: Richard L
authors.initials: RL
authors.lastname: Ehman
mesh_terms: D000328:Adult; D000465:Algorithms; D001706:Biopsy; D054459:Elasticity Imaging Techniques; D005260:Female; D019694:Hepatitis B, Chronic / Q000150:complications / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008103:Liver Cirrhosis / Q000175:diagnosis* / Q000473:pathology; D008111:Liver Function Tests; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies