Point shear wave elastography by ElastPQ accurately stages hepatic fibrosis in patients with NAFLD: A prospective, multicentric study

Background and Aims:

We face a global epidemic of non-alcoholic fatty liver disease (NAFLD). Vibration-controlled transient elastography (VCTE) represents an accurate non-invasive screening tool for significant fibrosis. The diagnostic value of point shear wave elastography (pSWE) techniques in NAFLD remains to be established.

Method:

In this prospective, multicentric study we performed paired liver stiffness measurements (LSM) by pSWE (ElastPQ®, Philips) and VCTE in NAFLD patients. Pearson's correlation and Lin's concordance correlation coefficient (CCC) for LSM by VCTE/pSWE were calculated. Diagnostic performance was assessed using VCTE as a reference standard and calculating the area under receiver operator characteristics curves (AUROC) for pSWE. Optimal cut-offs for significant fibrosis (≥F2) and cirrhosis (F4) were based on the Youden index.

Results:

280 paired measurements were obtained. 218 patients (139 men, 63.76%; median age: 58 years, median BMI: 29.03 kg/m²) meet the reliability criteria ((VCTE≤7kPa or VCTE IQR/Median ≤30%) and (ElastPQ≤7kPa and ElastPQ IQR/Median≤30%) and no ascites and VCTE not 75kPa (n = 10). The number of patients without significant fibrosis was 146 (66.97%), while 40 (18, 35%) and 32 (14.68%) had F2/F3 and F4-cirrhosis, respectively. The median LSM by VCTE and ElastPQ was 6kPa (IQR 5.76) and 5.41kPa (IQR 3.62), respectively. The Pearson's-correlation between VCTE and ElastPQ was r = 0.83 [CI95: 0.79 – 0.87] and the CCC = 0.71 [CI95: 0.53 – 0.83]. However, in cirrhotic F4-NAFLD we found lower r = 0.72 [CI95: 0.49 – 0.85] and the CCC = 0,51 [CI95: 0.22 – 0.71]. We determined an optimal ElastPQ-cut-off for F2-fibrosis at 6.0kPa (≥F2-AUROC = 0.94, sensitivity = 0.901, specificity = 0.869) and for cirrhosis at 8.2kPa (F4-AUROC = 0.94, Se = 0.86, specificity = 0.94). Cut-offs for ruling-in NAFLD-F2 fibrosis and NAFLD-F4-cirrhosis were determined at > 7.5kPa (PPV = 91%, sensitivity = 0.784, specificity = 0.974,) and > 10.1kPa (PPV = 0.78%, sensitivity = 0.833, specificity = 0.956), respectively.

Conclusion:

ElastPQ showed a strong correlation and a high level of concordance with VCTE in staging fibrosis in NAFLD patients. ElastPQ is accurate in diagnosing fibrosis and cirrhosis, particularly in. Specific ElastPQ cut-offs for NAFLD-associated, ≥F2-significant fibrosis and F4-cirrhosis were determined at > 7.5kPa and > 10.1kPa.