Three-Dimensional Shear Wave Elastography of Skeletal Muscle: Preliminary Study

ObjectivesTwo-dimensional (2D) shear wave elastography (SWE) can measure the elasticity of skeletal muscle, tendons, and ligaments. Three-dimensional (3D) SWE has been used to detect breast cancer but has not been applied to the musculoskeletal system. This study aimed to investigate whether 3D SWE could be used in skeletal muscles in vivo. MethodsThe study enrolled 20 healthy volunteers at Beijing Chaoyang Hospital from August to October 2016. Two-dimensional and 3D SWE scans were used to measure the Young modulus of the flexor carpi radialis in the relaxed state. Longitudinal and transverse scanning was performed. Data were analyzed by a 1-way analysis of variance/least significant difference post hoc test, a paired t test, and Bland-Altman plots. ResultsThe participants included 10 male and 10 female volunteers with a mean ageSD of 25 +/- 5 years. The Young modulus did not differ between 3D and 2D SWE for the sagittal plane (longitudinal scanning, 34.9 +/- 5.7 versus 32.7 +/- 5.2 kPa; P=.096) or transverse plane (transverse scanning, 9.1 +/- 2.1 versus 9.2 +/- 1.6 kPa; P=.877). The Young modulus did not differ between sagittal, transverse, and coronal planes for 3D SWE longitudinal scanning (34.9 +/- 5.7, 34.3 +/- 5.8, and 34.8 +/- 5.9 kPa, respectively; P=.936) or 3D SWE transverse scanning (9.1 +/- 2.0, 9.1 +/- 2.1, and 8.8 +/- 2.1 kPa; P=.838). However, the Young modulus for each individual plane (sagittal, transverse, or coronal) differed significantly between longitudinal and transverse scanning (P<.001). ConclusionsBoth 2D SWE and 3D SWE are suitable techniques for clinical use, depending on the examiner's experience/preference. However, 3D SWE provides a multiplanar/multislice view that better illustrates the spatial characteristics of muscle tissue. Three-dimensional SWE may be a new method for fully visualizing the musculoskeletal system.