Ultrasound-based grading of carpal tunnel syndrome: a comparative study of cross-sectional area and shear wave elastography at different wrist joint angles

Abstract Objectives Carpal tunnel syndrome (CTS) is a prevalent neuropathy where accurate diagnosis is crucial for effective treatment planning. This study introduces a novel approach for CTS grading using ultrasound, specifically through the analysis of the cross-sectional area (CSA) and shear wave elastography (SWE) of the median nerve in various wrist positions. Methods Our research involved subjects from outpatient clinics, diagnosed with CTS through nerve conduction studies (NCS), and a control group of healthy individuals. High-frequency ultrasound and SWE measurements were conducted in 3 wrist positions: straight, 45° extension, and 45° flexion. Results The key findings revealed significant differences in median nerve CSA and SWE values between the CTS and control groups across all wrist positions, with notable variances in SWE values correlating with wrist positioning. SWE demonstrated enhanced sensitivity and specificity in distinguishing between mild, moderate, and severe CTS, especially at 45° wrist flexion. In contrast, CSA measurements were limited in differentiating between the varying severity stages of CTS. Conclusions The study concludes that SWE, particularly at 45° wrist flexion, provides a more precise diagnostic benchmark for CTS severity grading than CSA. This advancement in non-invasive diagnostic methodology not only aids in accurate CTS grading but also has significant implications in formulating tailored treatment strategies, potentially reducing the reliance on more invasive diagnostic methods like NCS. Advances in knowledge This study marks a significant advancement in the ultrasound diagnosis of CTS. It particularly highlights the importance of applying SWE technology across various wrist joint angles, offering a new diagnostic benchmark. This discovery provides data support and additional insights for achieving an early consensus on ultrasound-based grading diagnosis of CTS.