Role of High-Resolution Ultrasound Compared to Magnetic Resonance Imaging in Assessment of Abnormalities of the Median Nerve in Carpal Tunnel Syndrome

Background: Carpal Tunnel Syndrome (CTS) is the most common entrapment neuropathy, predominantly impacting the median nerve at the wrist. Accurate diagnosis is crucial to avoid permanent nerve damage and optimize patient outcomes. Aim: To compare the diagnostic utility of high-resolution ultrasound (HRUS) and magnetic resonance imaging (MRI) in assessing structural abnormalities of the median nerve in patients with CTS. Methods: This prospective comparative study was performed at Benha University Hospitals over six months (July–December 2024), involving 50 adult patients diagnosed with CTS. All patients underwent nerve conduction studies, HRUS, and MRI. Key imaging parameters—including cross-sectional area (CSA), flattening ratio (FR), and palmar bowing (PB)—were measured and analyzed. Results: A total of 50 patients with clinically and electrophysiologically confirmed CTS were evaluated using HRUS and MRI. The mean age was 47.9 ± 11.6 years, with a female predominance (66%) and a mean BMI of 26.04 ± 3.61 kg/m². Diabetes mellitus was the most common comorbidity (42%). Ultrasound revealed elevated median nerve CSA in 94% of patients, altered echogenicity in 90%, and elevated bowing and flattening indices in 60% of cases each. Muscle atrophic changes were detected in 6%, and structural abnormalities were noted in 32%—most commonly tenosynovitis (62.5%). Conclusion: Both HRUS and MRI provide reliable, non-invasive assessment of median nerve abnormalities in CTS. HRUS, due to its accessibility, cost-effectiveness, and dynamic capabilities, may serve as a first-line imaging tool in CTS diagnosis.