title: Interobserver variability in transient elastography analysis of patients with chronic hepatitis C.
abstract: OBJECTIVE
  Transient elastography based on liver stiffness measurement is a non-invasive method to assess hepatic fibrosis. However, interobserver variability has led to controversy over its use in fibrosis evaluation. To evaluate the interobserver variation in transient elastography in chronic hepatitis C.
  
  
  METHODS
  We performed a cross-sectional study, analysing findings from two experienced operators who each assessed 195 patients by transient elastography on the same day. Liver stiffness measurement used to define fibrosis stages, based on METAVIR score, was: <7.1 as F0F1, 7.1-9.4 as F2, 9.5-12.4, as F3 and >12.4 kPa as F4. We also assessed interobserver variation in identification of potential oesophageal varices screening based on transient elastography.
  
  
  RESULTS
  The interobserver intraclass correlation coefficient was 0.940 (95% CI 0.863-0.967) and measurements made by operators correlated [Spearman's ρ = 0.924; P < 0.001]. However, the median liver stiffness measurement assessed by first operators was higher (11.5 vs 9.8 kPa; P < 0.001). The discordance between operators was 35% for at least one stage of fibrosis and 5% for two or more stages. Interobserver reliability values were κ = 0.61 for fibrosis stages F ≥ 2 and κ = 0.80 for cirrhosis. Among the 74 patients determined to have cirrhosis by at least one operator, there was considerable discordance in identification of those with indication for oesophageal varices screening (κ values from 0.13 to 0.61) according to several cut-offs.
  
  
  CONCLUSIONS
  Although a high correlation of liver stiffness measurement between operators, interobserver variability in transient elastography was not negligible. This method should not be used as the only screening tool for oesophageal varices in chronic hepatitis C.
authors.affiliation: Hepatology Department, Assistance Publique-Hôpitaux de Paris, Hôpital Pitié Salpêtrière, Paris, France; INSERM UMR_S 938 & Université Pierre et Marie Curie, Paris, France.
authors.forename: Hugo
authors.initials: H
authors.lastname: Perazzo
authors.forename: Flavia F
authors.initials: FF
authors.lastname: Fernandes
authors.forename: Amanda
authors.initials: A
authors.lastname: Gomes
authors.forename: Carlos
authors.initials: C
authors.lastname: Terra
authors.forename: Renata M
authors.initials: RM
authors.lastname: Perez
authors.forename: Fátima A F
authors.initials: FA
authors.lastname: Figueiredo
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D054459:Elasticity Imaging Techniques; D004932:Esophageal and Gastric Varices / Q000175:diagnosis*; D005260:Female; D019698:Hepatitis C, Chronic / Q000150:complications*; D006801:Humans; D008103:Liver Cirrhosis / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012307:Risk Factors; D055815:Young Adult
keywords: FibroScan; HCV; diagnostic; ultrasound