Real-time two-dimensional Shear-wave elastography for liver stiffness in children: Interobserver variation and effect
Hee Mang Yoon1, Young Ah Cho1, Jeong Rye Kim1
1Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, South Korea.
Objectives:
To evaluate interobserver variation and to assess the effect of the breathing technique on liver stiffness (LS) measurement using real-time two-dimensional shear-wave elastography (2D-SWE) in children.
Methods:
Patients who underwent real-time 2D-SWE by two operators (group 1) and patients who underwent real-time 2D-SWE by one operator using the free-breathing and breath-holding techniques (group 2) were included. In group 1, interobserver agreement was assessed using the intraclass correlation coefficient (ICC) and the 95% limits-of-agreement was analyzed to evaluate the maximum change in the LS values based on Bland-Altman analysis. In group 2, the Bland-Altman plot and the paired t-test were used to determine the effect of breathing technique on LS measurement.
Results:
The interobserver agreement of the LS measurement in group 1 (n=63) was excellent (ICC, 0.953), and the 95% limits-of-agreement was 31.8% of the mean LS values. In group 2 (n=45), the free-breathing technique revealed systematically lower LS with a mean difference of -11.1% of the mean LS values, compared to the breath-holding technique (P=0.016).
Conclusion:
LS measurement assessed by real-time 2D-SWE in children showed excellent interobserver agreement. Changes in LS values less than 31.8% of the mean LS values may represent the measurement error. The free-breathing technique showed lower LS values, compared to the breath-holding technique.
