Elastography Point Quantification in the evaluation of liver fibrosis in NAFLD patients

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease. Several non-invasive approaches to stage liver fibrosis in NAFLD patients are being developed. Elastography Point Quantification (ElastPQ) is a non-invasive method to assess liver fibrosis measuring liver stiffness. We evaluated the diagnostic performance of ElastPQ for identifying different degrees of fibrosis in NAFLD patients. We compared ElastPQ with other non-invasive tests and identify the best liver stiffness cut offs for every fibrosis stage. ElastPQ was performed in a training cohort of patients with biopsy-proved NAFLD, liver serum tests and Transient Elastography (TE). The diagnostic performance of ElastPQ was evaluated using AUROC and compared with TE, Fibrosis-4 score, NAFLD fibrosis score and AST/ALT. ElastPQ was performed in a validation cohort in order to validate the data. 106 patients with NAFLD were enrolled. The median stiffness values using ElastPQ was 4.69 kPa (2.82-29.86). The mean liver stiffness divided for category of fibrosis stage were: 4.18 kPa (mild fibrosis F0-1), 4.49 kPa (significant fibrosis F2), 6.89 kPa >(advanced fibrosis F3) and 12.14 kPa (cirrhosis F4). In multivariate analysis, liver stiffness was associated with the fibrosis stage (ß=2.987; p<0.001). The AUCs for the association with significant, advanced fibrosis and cirrhosis were 0.783 (95%IC 0.693-0.857), 0.855 (95%IC 0.773- 0.916) and 0.897 (95%IC 0.822-0.947), respectively. Diagnostic performance of ElastPQ compared to TE, resulted non-inferior in evaluating significant fibrosis (p=0.956), advanced fibrosis (p=0.171) and cirrhosis (p=0.773). ElastPQ had a higher diagnostic performance compared to FIB-4, NFS and AAR. The best fibrosis cuts off identified in the training cohort (80 patients enrolled) were 5.22 kPa, 6.3 kPa and 9.61 kPa respectively for fibrosis >F2, >F3 and F4. ElastPQ is a promising technique for liver fibrosis evaluation