Head-to-Head Comparison between Collagen Proportionate Area and Acoustic Radiation Force Impulse Elastography in Liver Fibrosis Quantification in Chronic Hepatitis C

BACKGROUND The aim of this study was to compare the diagnostic performances of the collagen proportionate area (CPA) and liver stiffness measurement (LSM) for liver fibrosis quantification in chronic hepatitis C (CHC). METHODS A total of 137 eligible consecutive Taiwanese patients (74 women and 63 men; age 21-80 years; median age 54 years), with CHC underwent LSM by using acoustic radiation force impulse (ARFI) elastography and an immediate percutaneous liver biopsy for METAVIR scoring. Liver tissue sections were stained using picrosirius red. Areas of the stained collagen and the tissue parenchyma were calculated in pixels. The ratio between the two areas was expressed as a CPA percentage. The result of LSM was presented as shear wave velocity (SWV). RESULTS METAVIR fibrosis (F) stages were dichotomized using the CPA (%) and SWV (m/s), and the optimal cut-off values were 7.47 and 1.59 for F1 versus F2-4; 12.56 and 1.73 for F1, 2 versus F3, 4; 15.32 and 1.96 for F1-3 versus F4. To dichotomize F1 versus F2-4, the areas under receiver operating characteristic curves for the CPA was 0.9349 (95% confidence interval: 0.8943-0.9755) and for SWV was 0.8434 (0.7762-0.9105) (CPA versus SWV, P = 0.0063). For F1, 2 versus F3, 4, the CPA was 0.9436 (0.9091-0.9781); SWV was 0.8997 (0.8444-0.9551) (P = 0.1587). For F1-3 versus F4, the CPA was 0.8647 (0.7944-0.9349); SWV was 0.9036 (0.8499-0.9573) (P = 0.2585). The CPA could be predicted in a linear regression formula by using SWV and platelet count (R2 = 0.524). CONCLUSIONS The CPA and ARFI elastography are promising tools for liver fibrosis evaluation. The CPA was superior to ARFI elastography in the diagnosis of significant fibrosis (≥ F2). The CPA may be independent of severe necroinflammation, which may augment liver stiffness.