Inter-operator and inter-device reproducibility of shear wave elastography in healthy muscle tissues

Abstract

Purpose: The study aimed to assess whether the more limiting factor in reproducibility of shear wave elastography (SWE) would be the operator dependency or the incompatibility of different ultrasound (US) devices. The interrater agreement with less experienced operators was studied.

Methods: A total of 24 healthy volunteers participated in the study (18 females, 6 males; range of age 27-55 years). SWE of biceps brachii (BB) and tibialis anterior (TA) muscles was performed on both sides from all participants in both longitudinal and transverse orientation of the transducer in respect to muscle fibers. Two operators repeated the SWE with two different US devices from different manufacturers (scanners 1 and 2).

Results: Intraclass correlation coefficient between the two operators was 0.91 (CI 0.88-0.93) for scanner 1 and 0.81 (CI 0.74-0.86) for scanner 2, respectively. Instead, there were significant differences in the SWE measurements between the two scanners, emphasizing in transverse orientation of the transducer. In the transverse transducer orientation, the mean shear wave velocity (SWV) in TA was 1.45 m/s (standard deviation [SD] ± 0.35 m/s) with scanner 1 and 2.35 m/s (SD ± 0.83 m/s) with scanner 2 (p < 0.001). In BB, the mean transverse SWV was 1.49 m/s (SD ± 0.35 m/s) with scanner 1 and 2.29 m/s (SD ± 0.63 m/s) with scanner 2 (p < 0.001). In longitudinal transducer orientation, the mean SWV in TA was 3.00 m/s (SD ± 0.73 m/s) with scanner 1 and 3.26 m/s (SD ± 0.42 m/s) with scanner 2 (p = 0.050). In BB, the mean longitudinal SWV was 3.60 m/s (SD ± 0.77 m/s) with scanner 1 and 3.96 m/s (SD ± 0.62 m/s) with scanner 2 (p = 0.019). The presented mean values were obtained by operator 1, there were no significant differences in the SWE measurements performed by the two operators.

Conclusion: The results implicate that the reproducibility of the SWE measurements depends rather on the used US device than on the operator. It is recommendable that clinics collect reference values with their own US device and consider threshold values presented in previous studies only directional.

Keywords: interobserver reliability; neuromuscular ultrasound; reproducibility; shear wave elastography.

Conflict of interest statement

The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

© 2022 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.

Figures

FIGURE 1

The figure demonstrates the transducer orientations on the biceps brachii (BB) muscle: (a) transverse transducer orientation; (b) longitudinal transducer orientation.

FIGURE 2

Boxplots showing both the difference in the shear wave velocity (SWV) values of the two ultrasound devices and the codirectional SWV measurements of the two operators. The y‐axis represents the SWV in m/s. The box indicates the first and third quartiles, the thick line within the box represents the median, and the bars represent the minimum and maximum values of SWV: (a) tibialis anterior (TA) muscle in transverse orientation; (b) biceps brachii (BB) muscles in transverse orientation; (c) TA in longitudinal orientation; and (d) BB in longitudinal orientation of the transducer.

FIGURE 3

The graph demonstrates the steadiness of the shear wave velocity in the biceps brachii (BB) of one volunteer during a follow‐up period of 4 days within 1 week. The shear wave elastography was performed in the morning and afternoon. SWV, shear wave velocity; measure unit is m/s.