Accuracy of Color Doppler Sonography in Diagnosis of Carpal Tunnel Syndrome

Carpal tunnel syndrome (CTS) is the most common upper extremity impingement neuropathy caused by median nerve compression within the carpal tunnel due to various conditions such as bone abnormalities, inflammation, trauma, neoplastic lesions and endocrinopathies. Increase in carpal tunnel pressure of more than 20 to 30 mmHg blocks the epineural blood flow; so, the nerve function is damaged. Carpal tunnel syndrome is primarily a clinical diagnosis supported by electrodiagnostic studies; in recent years, different imaging modalities, including magnetic resonance imaging (MRI) and ultrasound, are suggested for diagnosis of carpal tunnel syndrome. During November 2011 and May 2013, 84 patients clinically suspicious for carpal tunnel syndrome were enrolled in our study; the age of patients ranged from 19 to 66 with the average of 43 years and the sex ratio of women to men was 2.7:1. All the patients underwent electerodiagnostic tests (EDT) as the gold standard diagnostic modality and the results of color Doppler sonography (CDS) were compared with electerodiagnostic findings. According to the ecterodiagnostic tests, patients with positive results of carpal tunnel syndrome were divided into three groups of severity including mild with 9 patients (11%), moderate with 14 cases (17%) and severe with 18 patients (21%). Sensitivity of color Doppler sonography for diagnosis of carpal tunnel syndrome was almost 83%, 71% and 55% in severe, moderate and mild groups of carpal tunnel syndrome, respectively. Specificity of this imaging modality was determined near to 81% in all three groups of the patients. In addition to electerodiagnostic tests, which are considered as the modality of choice for diagnosis of carpal tunnel syndrome, Doppler ultrasound can be a non-invasive imaging procedure for evaluation of patients that are clinically suspicious to this syndrome. Considering three groups of carpal tunnel syndrome based on severity of electerodiagnostic signs, results of color Doppler sonography is more reliable in patients with severe signs.