Establishing Reliability Criteria for Liver ElastPQ Shear Wave Elastography (ElastPQ-SWE): Comparison Between 10, 5 and 3 Measurements.

ABSTRACT

PURPOSE: ElastPQ is a new elastography technique for non-invasive liver fibrosis staging. However, it does not have validated reliability criteria. We tested the reliability of a different number of measurements in patients with chronic liver disease and explored whether the application of quality criteria improves the diagnostic performance. MATERIALS AND METHODS: All patients underwent liver stiffness assessment (LSM) with ElastPQ and Fibroscan (F-TE). The mean, median, standard deviation (SD) and interquartile range (IQR) of 10, 5 and 3 measurements were retrospectively collected for each patient and compared to each other. Liver histology was available in a subset of patients. RESULTS: Overall, 400 patients met the inclusion criteria. Non-alcoholic fatty liver disease (NAFLD) was the most represented etiology (75 %), followed by primary sclerosing cholangitis (PSC), primary biliary cholangitis (PBC) and autoimmune hepatitis (AIH). The correlation of medians was significantly better between 10 and 5 measurements than between 10 and 3. The difference of medians was significant only in the comparison between 10 and 3 measurements. The correlation between ElastPQ and F-TE was equally good for 10 and 5 measurements and significantly improved after an IQR/median ≤ 30 % was applied. The diagnostic performance of ElastPQ was better with the median value of 10 and 5 measurements and improved if LSM values were obtained with IQR/M ≤ 30 %. CONCLUSION: The median value of 5 valid LSMs suffices for the reliable estimation of liver stiffness using ElastPQ. The quality criterion of IQR/M ≤ 30 % should also be followed when using this technique.