Evaluation of ultrasound point shear wave elastography reliability in an elasticity phantom

Purpose: To date, limited studies have specifically addressed the reliability of ultrasound point shear-wave elastography (pSWE). Therefore, the aim of the present study was to assess the reproducibility of ultrasound pSWE within and between operators using two ultrasound scanners. Methods: iU22 and EPIQ7 ultrasound scanners were used to assess the reliability of pSWE measurements of lesions at a depth of 3.5 cm in an elasticity phantom using a curvilinear 5-1 MHz transducer. The intra-operator, inter-operator, and inter-scanner reproducibility of pSWE was assessed using intraclass correlation coefficients (ICCs). Bland-Altman plots were used to establish bias and limits of agreement (LoA) between measurements. The accuracy of pSWE from manufacturer values was determined using the one-sample t-test. Results: Intra-operator agreement was excellent, with an ICC >0.90. The bias in measurements for operator A was -0.36 +/- 3.13 kPa (LoA, -6.47 to 5.75), and for operator B it was -1.97 kPa (LoA, -10.25 to 14.21). Inter-operator agreement was excellent, with an ICC of 0.95. The bias in measurements between operators was -0.42 +/- 5.00 kPa (LoA, -10.24 to 9.38). The inter-scanner agreement between EPIQ7 and iU22 was excellent, with an ICC of 0.96. The bias in measurements between scanners was 1.74 +/- 4.44 kPa (LoA, -6.95 to 10.45). There was significant overestimation for L I (17.75%) and L II (31.14%) and underestimation for L III (-15.28%) and L VI (-98.00%) relative to the manufacturer-reported values. Conclusion: Phantom ultrasound pSWE was reproducible within and between operators, and between Philips ultrasound scanners; further studies using different ultrasound systems and transducers are required.