Non-Invasive Assessment of Liver Fibrosis in a Rat Model: Comparison of Shear Wave Elastography with Serologic Tests

Background: Non-invasive evaluation of hepatic fibrosis, especially serum biomarkers and ultrasound elastography, has vigorously developed during the past decades. Objectives: The purpose of this study was to evaluate the diagnostic performance of the latest generation of ultrasound elastography-two-dimensional real-time shear wave elastography (SWE) in accessing liver fibrosis progression in comparison with serologic tests in a rat model. Materials and Methods: Liver fibrosis was induced in 108 rats (control group: 18 rats, experiment group: 90 rats) by intraperitoneal injection of thioacetamide (300mg/kg, twice a week for 12 weeks). SWE examination was done by two operators. Hyaluronic acid (HA), aspartate aminotransferase (AST) to platelet (PLT) ratio index (APRI), AST to alanine aminotransferase (ALT) ratio (AAR) were used for serology tests. Histological fibrosis stages (F0-F4) according to the Scheuer scoring system were referred as the gold standard. Diagnostic performance of elastography and serology methods were determined by the areas under receiver operating characteristic curve (AUROC). Results: Liver stiffness values increased with the progression of hepatic fibrosis. Liver stiffness assessed by SWE exhibited a strong positive correlation with histological fibrosis stages (r = 0.849, P < 0.001). SWE showed a better diagnostic performance than the selected serological biomarkers HA, APRI, and AAR(AUROC for SWE, HA, APRI, and AAR were 0.933,0.707, 0.714, and 0.691 in diagnosing F >= F2 and 0.986, 0.807, 0.870, and 0.770 in diagnosing F = F4, respectively). Conclusion: Ultrasound elastography SWE technique is a reliable method for noninvasive evaluation of liver fibrosis in comparison with the serological biomarkers, HA, APRI, and AAR.