The role of ultrasonographic measurements of the median nerve in the diagnosis of carpal tunnel syndrome

AIM: The aim of study was to assess the usefulness of ultrasonographic measurements of the median nerve in the diagnosis of carpal tunnel syndrome. MATERIALS AND METHODS: Eighty-six patients with carpal tunnel syndrome confirmed by electromyography and 45 asymptomatic controls were included in the study and underwent high-resolution ultrasonography of the wrists. The crosssectional area and flattening ratio at the level of the pisiform bone of the proximal carpal tunnel were measured. Data from the patient group and control group were compared to determine the statistical significance. The accuracy of the ultrasonographic diagnostic criteria for carpal tunnel syndrome was evaluated using receiver-operating characteristic (ROC) analysis. RESULTS: One hundred and forty-eight wrists of 86 patients with carpal. tunnel syndrome and 76 wrists of 45 control patients were examined. All measurements showed significant differences between patients and controls. Increased crosssectional area of the median nerve was the most predictive measurement of carpal tunnel syndrome. Using the ROC curve, a cut-off value of > 10.5 mm(2) at the level of pisiform bone provided a diagnostic sensitivity of 89% and specificity of 94.7% CONCLUSION: The ultrasonographic measurement of the median nerve crosssectional area is a sensitive, specific and useful non-invasive method for the diagnosis of carpal. tunnel syndrome. (C) 2004 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.