Comparison of the Diagnostic Utility of Electromyography, Ultrasonography, Computed Tomography, and Magnetic Resonance Imaging in Idiopathic Carpal Tunnel Syndrome Determined by Clinical Findings

BACKGROUND: Carpal tunnel syndrome (CTS) is the most common nerve entrapment syndrome. It is sometimes difficult to diagnose, and a late diagnosis may result in permanent nerve damage. Electromyography (EMG), ultrasonography (US), magnetic resonance imaging (MRI), and computed tomography (CT) may be performed for the diagnosis. The diagnostic accuracy of these tests is well documented, but most of these studies accept EMG as the gold standard. OBJECTIVE: To evaluate the diagnostic accuracy of EMG, MRI, CT, and US for the diagnosis of carpal tunnel syndrome with the use of clinical findings as the gold standard. METHODS: Patients suspected to have CTS on presentation to the outpatient clinic were evaluated. The tests were performed after a detailed physical examination. Both wrists of the 69 patients in the study were investigated. RESULTS: The diagnostic accuracies of all the tests were found to be sufficient. Although EMG seemed to have the highest sensitivity and specificity, there was no statistically significant difference between the tests. CONCLUSION: EMG or US could be used as the first-step test in most cases. If they are both available, EMG should be the first choice. They may be performed together when diagnosis is challenging. CT may especially be preferred for bone-related pathological conditions, whereas MRI may be preferred for soft tissue-related pathological conditions. Even though imaging studies have been proven to be powerful diagnostic tools for CTS, no conclusive information currently exists to support replacing EMG with imaging studies.