Comparison of Median Nerve Cross-sectional Area on 3-T MRI in Patients With Carpal Tunnel Syndrome.

This study correlated morphologic abnormalities of idiopathic carpal tunnel syndrome (CTS) with the severity of CTS using 3-T magnetic resonance imaging (MRI). The relationship of the severity of CTS and the cross-sectional area of the median nerve (CSA) was assessed at several levels. Seventy wrists of 35 patients (27 women and 8 men) with unilateral idiopathic CTS underwent nerve conduction study and 3-T MRI of the wrist. The CSA at 4 levels (distal radioulnar joint, body of scaphoid, tubercule of scaphoid, and hook of hamate) and the thickness of the transverse carpal ligament at 3 levels in both affected and unaffected hands were measured using 3-T MRI and correlated with the severity of CTS assessed with distal motor latency. The CSA in the affected hand at the scaphoid body level was significantly higher than in the unaffected hand. The CSA at the scaphoid body level was positively correlated with distal motor latency in the affected hand. The CSA in the affected hand at the scaphoid tubercule level was significantly lower than in the unaffected hand. The CSA had a negative correlation with distal motor latency at the scaphoid tubercule level. The CSA at the distal radioulnar joint and the hamate hook was not significantly different between the affected hand and the unaffected hand. The CSA at the distal radioulnar joint level and hook level were not correlated significantly with distal motor latency in the affected hand. The mean CSA of the affected hand at the scaphoid body level was highest in 4 levels. [Orthopedics. 2017; 40(1):e77-e81.].