To evaluate the application value of fibrosis (F) index and activity (A) index of combinational elastography in stratified diagnosis of liver fibrosis and inflammation.

We collected 202 patients with chronic liver disease who visited Huashan Hospital Affiliated to Fudan University from September 2019 to April 2021. These patients received percutaneous liver biopsy or partial hepatectomy to obtain pathological results. Among them, 49 patients underwent partial hepatectomy due to liver space occupying lesions, and 153 underwent liver biopsy due to diffuse liver disease. All patients underwent combinational elasticity examination before surgery to obtain liver fibrosis-related F index and inflammation activity-related A index. The pathological diagnosis was used as the gold standard for liver fibrosis staging (S0~S4) and inflammatory activity classification (G0~G4). Kruskal-Wallis test and Bonferroni correction test were used to compare the differences in F index among different fibrosis stages and A index among different inflammatory activity grades. DeLong test was used to compare the performance of F index and shear wave velocity, real-time tissue elastography liver fibrosis index (LFI), and aspartate aminotransferase platelet ratio index (APRI) in non-invasive diagnosis of liver fibrosis.

The median F index of patients with liver fibrosis stages S0 (40 cases), S1 (42 cases), S2 (41 cases), S3 (34 cases), and S4 (45 cases) was 0.89, 1.17, 1.45, 1.75, and 2.30, respectively. The difference in the median F index of adjacent fibrosis stages was statistically significant (P＜0.05). The cutoff values of F index in the diagnosis of fibrosis stages ≥S1, ≥S2, ≥S3, and ≥S4 were 1.14, 1.45, 1.50, and 1.63, and the area under the curve (AUC) values were 0.91, 0.89, 0.90, and 0.91, respectively, which were significantly higher than those of LFI (AUC=0.66, 0.68, 0.69, and 0.69, respectively) and APRI (AUC=0.71, 0.68, 0.72, and 0.77, respectively) (P＜0.05). The AUC values of F index in diagnosing fibrosis stages ≥S1 and ≥S2 were significantly higher than those of shear wave velocity (AUC=0.84 and 0.85, respectively) (P＜0.05). The median A index for inflammatory activity grades G0 (26 cases), G1 (86 cases), G2 (68 cases), and G3-4 (22 cases) were 0.83, 0.99, 1.29, and 1.69, respectively. The difference in median A index between adjacent grades was statistically significant (P＜0.05). The cutoff values of A index for distinguishing ≥G1, ≥G2, and ≥G3-4 were 0.87, 1.15, and 1.41, respectively, and the AUC values were 0.86, 0.87, and 0.92, respectively.

The A index obtained by combinational elastography is a good indicator in assessing the grade of liver inflammation activity. F index corrects the influence of inflammatory activity of hepatocytes on the measurement of liver tissue stiffness, and can more accurately diagnose the stage of liver fibrosis.