Multiparametric Ultrasound Assessment of Carpal Tunnel Syndrome: Beyond Nerve Cross-sectional Area

Carpal tunnel syndrome (CTS), the most common mononeuropathy, results from compression of the median nerve within the fibro-osseous carpal tunnel. Diagnosis is typically based on clinical evaluation and confirmed by nerve conduction studies. However, ultrasound (US) has emerged as a valuable noninvasive adjunct for CTS confirmation, offering potential advantages over electrodiagnostic testing in terms of patient comfort and diagnostic accuracy. This review begins with a concise summary of carpal tunnel anatomy and CTS pathophysiology as a foundation for exploring the diverse applications of US in CTS evaluation. B-mode US assessment is presented with a focus on cross-sectional imaging and dynamic evaluations, including the transverse translocation and longitudinal gliding of the median nerve. We also review current methods for assessing vascularization in CTS and explore the usefulness of elastography in CTS evaluation. The advantages and limitations of each US method are elucidated, highlighting their practical utility in clinical practice.