Diagnosis of carpal tunnel syndrome using ultrasonography

Background The carpal tunnel syndrome (CTS) is the most common peripheral entrapment neuropathy. Therefore, this study aimed to determine the diagnostic efficacy of the gray-scale and Doppler sonography in the diagnosis and grading of patients with CTS. Patients and methods This is a prospective study conducted on 40 adult patients (28 women and 12 men; 76 wrists). Twenty were suffering from CTS, and the other 20 were healthy controls. All of them were examined using a 7–12 MHz linear transducer. Presence of median nerve edema, swelling, flattening ratio of the median nerve, and bowing of the flexor retinaculum were evaluated by gray-scale sonography while Doppler sonography evaluated intraneural hypervascularity. Sensitivity and specificity were calculated considering the nerve conduction studies as a gold standard. Results Cross-sectional area (CSA) inlet has the highest sensitivity and accuracy in the diagnosis of CTS (92 and 90%, respectively) in addition to subjective ultrasonography findings such as nerve edema and nerve mobility which had a100% specificity. Doppler examination findings also had a high specificity of 92%. Combined CSA inlet and the swelling ratio have a higher diagnostic accuracy of 95% in diagnosing CTS compared with CSA inlet alone. The CSA inlet used in the grading of CTS with cutoff values of 9–15 mm2 for mild CTS, CSA more than 15 mm^2 for moderate CTS, and CSA more than or equal to 16 mm^2 for severe CTS. Conclusion A combination of CSA inlet and swelling ratio have the highest sensitivity and accuracy than CSA inlet alone in diagnosing CTS.