Comparison of median nerve area measurement between MRI and electromyography in patients diagnosed with carpal tunnel syndrome

Abstract

Background. Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy that occurs when the median nerve is compressed within the carpal tunnel. Electromyography (EMG) is accepted as the most frequently used and important diagnostic method for CTS. Recently, magnetic resonance imaging (MRI) has begun to be used in CTS patients to directly visualize the median nerve and examine the changes occurring in the nerve structure. Objectives. In this study, the area of the median nerve was measured at various levels in the wrist in patients with CTS using MRI, examining its relationship with signal increase, and comparing this to results obtained with EMG. Materials and methods. Overall, 35 patients diagnosed with CTS were included in the study. Patients with normal-mild and moderate-severe EMG tests were included in the study; wrist MRI was taken to investigate the area/mm2 of the median nerve at various levels and whether there was an increase in signal. Thenar muscles included in the imaging were also evaluated. Results. Of the 35 patients included in the study, 24 were women (68.6%) and 11 were men (31.4%). Measurements of the average median nerve area measured in mm2 at the distal radioulnar junction (DRUJ) and the median nerve area measured in mm2 at the hamate bone level were obtained, showing that DRUJ and hamate bone distance measurements were higher in patients with positive EMG. Electromyography findings were also significantly positive in patients with increased signal. Conclusions. In some cases, the diagnosis of CTS can be easily made with history and physical examination or employing confirmatory tests such as EMG, which is considered the gold standard. Magnetic resonsnace imaging can be used as an alternative method for imaging the median nerve in patients with CTS. In our study, EMG findings were also significantly positive in patients with increased signal on MRI, making it a preferable method, especially in soft tissue-related pathological cases.