1Department of Radiology, Seoul National University Hospital, Seoul, Korea 2Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, Korea 3Department of Radiology, Pusan National University Yangsan Hospital, Yangsan, Korea
Received: January 2, 2019; Accepted: March 23, 2019. Published online: April 15, 2019.
Purpose: To compare the technical success and reliable measurement rates of three shear wave elastography (SWE) techniques, and to assess the inter-platform reproducibility of the resultant liver stiffness measurements.
Methods: This prospective study comprised 54 patients with liver diseases. Liver stiffness (LS) measurements were obtained using two-point SWE (pSWE) techniques (VTQ and S-Shearwave), two-dimensional (2D) SWE, and transient elastography (TE) serving as the reference standard. Technical success rates and reliable measurements of the three techniques were compared. LS values measured using the three techniques and TE were correlated using Spearman correlation coefficients and 95% Bland-Altman limits of agreement. Intra-class correlation coefficients (ICC) were used to analyze the inter-platform reproducibility of LS measurements.
Results: Three SWE techniques and TE showed similar technical success rates (p = 0.682) but demonstrated significant differences in the reliability of LS measurements (p =0.006) and mean LS measurements (p <0.0001). Despite strong correlations (r =0.73-0.94) between SWE systems, various degrees of inter-platform reproducibility (ICC = 0.58-0.92) were observed for the three SWE techniques. The best agreement was observed between S-Shearwave and TE (ICC = 0.92), and the worst agreement was observed between 2D-SWE and TE (ICC = 0.58). In Bland-Altman analysis, tendency toward lower LS values with the three SWE techniques than TE in patients with F3 and F4 was observed.
Conclusion: Significant inter-system variability was observed in LS measurements of the three SWE techniques. Therefore, LS values measured using different SWE techniques should not be used interchangeably for longitudinal follow-up.