Accuracy of Real-Time Tissue Elastography for the Evaluation of Hepatic Fibrosis in Patients with Chronic Hepatitis B: A Prospective Multicenter Study

BACKGROUND: The prognosis and management of hepatic fibrosis are closely related to the stage of the disease. The limitations of liver biopsy, which is the gold standard for treatment, include its invasiveness and sampling error. Ultrasound elasticity might be the most promising imaging technology for the noninvasive and accurate assessment of hepatic fibrosis. Real-time tissue elastography (RTE) measures the relative stiffness of the tissue in the region of interest caused by the heartbeat. Many studies have verified that RTE is useful for the diagnosis of hepatic fibrosis in patients with chronic hepatitis C (CHC). PURPOSE: To determine the formula of the liver fibrosis index for chronic hepatitis B (BLFI) and to validate the diagnostic accuracy of the BLFI for hepatic fibrosis compared with the liver fibrosis index (LFI). MATERIALS AND METHODS: RTE was performed in 747 prospectively enrolled patients with chronic hepatitis B (CHB) or cirrhosis from 8 centers in China; 375 patients were analyzed as the training set, and 372 patients were evaluated as the validation set. The fibrosis stage was diagnosed from pathological specimens obtained by ultrasound-guided liver biopsy. Nine image features were measured from strain images, and the new formula for the BLFI was obtained by combining the nine imaging features of the RTE images using multiple regression analysis of the training set. The BLFI and LFI were compared with the pathological fibrosis stage at diagnosis, and the diagnostic performances of the indexes were compared. RESULTS: The Spearman correlation coefficient between the BLFI and hepatic fibrosis stages was significantly positive (r = 0.711, p < 0.001), and significant differences were present between all disease stages. The areas under the receiver-operating characteristic (AUROC) curves of the BLFI and LFI for predicting significant fibrosis (S0-S1 vs. S2-S4) were 0.858 and 0.858, respectively. For cirrhosis (S0-S3 vs. S4), the AUROC curves of the BLFI and LFI were 0.868 and 0.862, respectively. CONCLUSION: The results of this large, multicenter study confirmed that RTE is valuable for the diagnosis of hepatic fibrosis in patients with CHB. However, the diagnostic efficiencies of the new BLFI and the original LFI, which were based on CHC, for the assessment of CHB hepatic fibrosis were similar; thus, the LFI has the potential to be used to directly evaluate the extent of hepatic fibrosis in patients with CHB.