SWE for diagnosing and grading Carpal Tunnel Syndrome

 

Abstract

Objective

To quantify the shear velocity and stiffness of the median nerve (MN) with shear wave elastography (SWE) at the carpal tunnel entrance and determine whether SWE is useful for diagnosing and staging carpal tunnel syndrome (CTS).

Materials and methods

The study included 58 patients (79 wrists) with clinical and electroneuromyographic diagnoses of CTS and 55 healthy controls (63 wrists). MN shear velocity and stiffness were measured by SWE on the axial plane in both groups. The differences between CTS patients and controls and between different grades of CTS based on electrodiagnostic tests were studied using Student’s t test and ANOVA with ROC analysis.

Results

The mean MN shear velocity and stiffness were significantly greater in CTS patients (2.5 ± 0.37 m/s and 19.4 ± 5.8 kPa) than in controls (1.91 ± 0.24 m/s and 11.1 ± 3.0 kPa) (p < 0.001) and greater in the severe CTS group (2.69 ± 0.39 m/s and 22.4 ± 7.1 kPa) than in the mild CTS group (2.37 ± 0.35 m/s and 17.3 ± 4,8 kPa). The cutoff value for the shear velocity was 2.13 m/s, with 86% and 82% sensitivity and specificity, respectively, and the cutoff value for stiffness was 13.6 kPa, with 87% and 82% sensitivity and specificity.

Conclusion

MN shear velocity and stiffness are significantly higher in CTS patients. SWE can be used to diagnose CTS and distinguish between patients with mild and severe disease.