Liver fibrosis in patients with chronic hepatitis C: noninvasive diagnosis by means of real-time tissue elastography--establishment of the method for measurement.

PURPOSE: To prospectively measure liver stiffness with real-time tissue elastography in patients with chronic hepatitis C and to compare the results with those of clinical assessment of fibrosis by using histologic stage as the reference standard.

MATERIALS AND

METHODS

All subjects gave informed consent, and the study was approved by the institutional ethics committee. Seventy hospitalized patients (46 men, 24 women; mean age, 65.5 years ± 11.7 [standard deviation]; age range, 33-87 years) with chronic hepatitis C underwent real-time elastography between January 2009 and September 2009. Elastography was performed at four liver locations by two independent observers. The elastic ratio (ratio of the value in the intrahepatic venous small vessels divided by the value in the hepatic parenchyma) was calculated and was compared with histologic fibrosis stage at liver biopsy. The elastic ratio and clinical fibrosis markers were assessed by using receiver operating characteristic (ROC) analysis. The differences between body site and observers were assessed with κ statistics and intraclass correlation coefficients (ICCs).

RESULTS

Real-time tissue elastography cutoff values were 2.73 for F of 2 or greater, 3.25 for F of 3 or greater, and 3.93 for F of 4. No site differences were observed (κ = 0.835, ICC = 0.966), and the elastic ratio measurement was correlated between the two examiners (r(2) = 0.869, P < .0001). The areas under the ROC curves for elastic ratio, hyaluronic acid, type IV collagen, aspartate aminotransferase-to-platelet ratio index, FibroIndex, Forns score, and Hepascore were 0.95, 0.32, 0.73, 0.76, 0.76, 0.87, and 0.70, respectively; the elastic ratio performed better than the serum fibrosis markers and other scores.

CONCLUSION

Real-time tissue elastography is not invasive and could be used to evaluate liver fibrosis in patients with chronic hepatitis C.

SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10100319/-/DC1.