Reproducibility of transient elastography in the evaluation of liver fibrosis in patients with chronic liver disease
- Mirella Fraquelli1,
- Cristina Rigamonti2,
- Giovanni Casazza3,
- Dario Conte1,
- Maria Francesca Donato2,
- Guido Ronchi2,
- Massimo Colombo2
- 1Second Division of Gastroenterology, Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Milan, Italy
- 2First Division of Gastroenterology, A.M. & A. Migliavacca Center for Liver Disease, Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Milan, Italy
- 3Istituto di Statistica Medica e Biometria, Università degli Studi di Milano, Milan, Italy
- Correspondence to:
Dr Mirella Fraquelli
Department of Internal Medicine, Pad Granelli III piano, IRCCS Fondazione Policlinico, Mangiagalli e Regina Elena, Via F Sforza 35, 20122 Milano, Italy;
- Accepted 16 January 2007
- Revised 22 December 2006
- Published Online First 25 January 2007
Objective: Transient elastography (TE) is gaining popularity as a non-invasive method for predicting liver fibrosis, but intraobserver and interobserver agreement and factors influencing TE reproducibility have not been adequately assessed. This study investigated these aspects.
Setting: Tertiary referral liver unit.
Patients: Over a 4-month period, 200 patients with chronic liver disease (CLD) with varying aetiology consecutively underwent TE and liver biopsy.
Interventions: TE was performed twice by two different operators either concomitantly or within 3 days of the bioptic procedure (METAVIR classification).
Main outcome measures: Intraobserver and interobserver agreement were analysed using the intraclass correlation coefficient (ICC) and correlated with different patient-related and liver disease-related covariates.
Results: 800 TE examinations were performed, with an indeterminate result rate of 2.4%. The overall interobserver agreement ICC was 0.98 (95% CI 0.977 to 0.987). Increased body mass index (>25 kg/m2), steatosis, and low staging grades (fibrosis (F) stage <2) were significantly associated with reduced ICC (p<0.05). Intraobserver agreement ICC was 0.98 for both raters. Using receiver operating characteristic curves, three diagnostic TE thresholds were identified: >7.9 kPa for F⩾2, >10.3 for F⩾3 and >11.9 for F = 4. TE values assessed by the two raters fell within the same cut-off of fibrosis in 88% of the cases for F⩾2, in 92% for F⩾3 and 91% for F = 4.
Conclusions: TE is a highly reproducible and user-friendly technique for assessing liver fibrosis in patients with CLD. However, because TE reproducibility is significantly reduced (p<0.05) in patients with steatosis, increased BMI and lower degrees of hepatic fibrosis, caution is warranted in the clinical use of TE as a surrogate for liver biopsy.
- A, necroinflammatory activity
- ALT, alanine aminotransferase
- AST, aspartate aminostransferase
- BMI, body mass index
- CLD, chronic liver disease
- F, fibrosis stage
- GGTP, and gammaglutamiltransferase
- HBV, hepatitis B virus
- HCV, hepatitis B virus
- ICC, intraclass correlation coefficient
- IQR, interquartile range
- NASH, non-alcoholic steatohepatitis
- ROC, receiver operating characteristic
- TE, transient elastography
- US, ultrasonography
Published Online First 25 January 2007
Competing interests: None to declare