Shear wave elastography: An accurate technique to stage liver fibrosis in chronic liver diseases

Abstract

Objectives: The goals of this study were to assess the diagnostic accuracy of shear wave elastography (SWE) using the results of histopathological analysis as a standard of reference and compare the results of SWE and those of transient elastography (TE) to the degree of fibrosis as evaluated by histomorphometry.

Patients and methods: Adult patients who were scheduled to undergo liver biopsy were prospectively enrolled in the study. The diagnostic performances of SWE were assessed using AUROC curve analysis according to fibrosis thresholds defined by ≥F2 (significant fibrosis), ≥F3 (advanced fibrosis) and F4 (cirrhosis). Additional analyses using the Obuchowski measures for pairwise comparisons of fibrosis stages were performed. In a subgroup of 55 patients, the relationships between stiffness as measured using SWE and TE and the percentage of fibrosis were compared using Spearman's rank coefficient.

Results: Among the initially enrolled 170 patients, 148/170 (87%) had successful SWE acquisition and formed the study population. SWE sensitivity and specificity were respectively 85.1% and 82.7% (≥F2), 88.9% and 90.3% (≥F3), 93.3% and 98.3% (F4). The AUROC curves of SWE along with their 95% confidence intervals (CI) were respectively 0.904 (95%CI: 0.845-0.946) for fibrosis ≥F2; 0.958 (95%CI: 0.912-0.984) for fibrosis ≥F3 and 0.988 (95%CI: 0.955-0.999) for fibrosis=F4. The global Obuchowski measure was 0.953±0.007. In the subgroup study, a significant correlation was found between the percentage of fibrosis and stiffness as assessed by SWE (r=0.77; 95%CI: 0.63-0.86; P<0.0001) and by TE (r=0.65; 95%CI: 0.47-0.78; P<0.01).

Conclusion: SWE is accurate to assess liver fibrosis in patients with chronic liver disease.

Keywords: Cirrhosis; Elasticity imaging techniques; Elastography; Liver fibrosis; Sonoelastography.