title: Elastography for the diagnosis of severity of fibrosis in chronic liver disease: a meta-analysis of diagnostic accuracy.
abstract: OBJECTIVE
  Transient elastography is a non-invasive method, for the assessment of hepatic fibrosis, developed as an alternative to liver biopsy. We studied the performance of elastography for diagnosis of fibrosis using meta-analysis.
  
  
  METHODS
  MEDLINE, EMBASE, SCI, Cochrane Library, conference abstracts books, and article references were searched. We included studies using biopsy as a reference standard, with the data necessary to calculate the true and false positive, true and false negative diagnostic results of elastography for a fibrosis stage, and with a 3-month maximum interval between tests. The quality of the studies was rated with the QUADAS tool.
  
  
  RESULTS
  We identified 40 eligible studies. Summary sensitivity and specificity was 0.79 (95% CI 0.74-0.82) and 0.78 (95% CI 0.72-0.83) for F2 stage and 0.83 (95% CI 0.79-0.86) and 0.89 (95% CI 0.87-0.91) for cirrhosis. After an elastography result at/over the threshold value for F2 or cirrhosis ("positive" result), the corresponding post-test probability for their presence (if pre-test probability was 50%) was 78%, and 88% respectively, while, if values were below these thresholds ("negative" result), the post-test probability was 21% and 16%, respectively. No optimal stiffness cut-offs for individual fibrosis stages were validated in independent cohorts and cut-offs had a wide range and overlap within and between stages.
  
  
  CONCLUSIONS
  Elastography theoretically has good sensitivity and specificity for cirrhosis (and less for lesser degrees of fibrosis); however, it should be cautiously applied to everyday clinical practice because there is no validation of the stiffness cut-offs for the various stages. Such validation is required before elastography is considered sufficiently accurate for non-invasive staging of fibrosis.
authors.affiliation: The Royal Free Sheila Sherlock Liver Centre, Royal Free Hospital, London NW3 2QG, UK.
authors.forename: E A
authors.initials: EA
authors.lastname: Tsochatzis
authors.forename: K S
authors.initials: KS
authors.lastname: Gurusamy
authors.forename: S
authors.initials: S
authors.lastname: Ntaoula
authors.forename: E
authors.initials: E
authors.lastname: Cholongitas
authors.forename: B R
authors.initials: BR
authors.lastname: Davidson
authors.forename: A K
authors.initials: AK
authors.lastname: Burroughs
mesh_terms: D001706:Biopsy; D002908:Chronic Disease; D054459:Elasticity Imaging Techniques; D008099:Liver / Q000473:pathology; D008103:Liver Cirrhosis / Q000175:diagnosis* / Q000473:pathology; D008107:Liver Diseases / Q000175:diagnosis* / Q000473:pathology; D012720:Severity of Illness Index