Point quantification elastography in the evaluation of liver elasticity in healthy volunteers: a reliability study based on operator expertise

Purpose: The assessment of liver fibrosis is essential in the management of patients with chronic liver diseases. Liver biopsy is considered the gold standard procedure for this purpose, though the recent development of new elastosonographic techniques to measure liver stiffness (LS) noninvasively is promising. Point quantification elastography (PQE) showed good results but less is known about the level of skill needed to obtain reliable results. The aim of the study was to evaluate the reproducibility of PQE in assessing LS in healthy subjects comparing three operators with different expertise. Methods: Between December 2012 and April 2013, 50 consecutive healthy volunteers (18 males, 32 females), median age 30 years (range 25–66) and BMI 22.4 (range 16.7–33.6) were submitted to PQE (iU22 Philips, Bothell, WA, USA) by three operators: two US and elastography providers (one expert and one with intermediate skill) and a skilled transient elastography (Fibroscan) operator with no expertise in US. Intra- and inter-observer agreements were assessed by intraclass correlation coefficient (ICC). Results: PQE measurement was obtained in all subjects by all evaluators. No significant differences of mean liver stiffness were found among operators (P = 0.980). Intra-observer agreement was excellent 0.918 (0.941 for expert, 0.917 for intermediate and 0.888 for novice). The ICC of the inter-observer agreement among the three ratters was excellent (0.882) and was higher in normal than overweight patients (0.923 vs. 0.603; P = 0.011). Conclusion: PQE is a reliable and reproducible non-invasive method for the assessment of LE, and can be performed also by a non-experienced operator.