Ultrasonography of palm to elbow segment of median nerve in different degrees of diabetic polyneuropathy

Objective: To identify the relationship between the ultrasonographic cross-sectional area (CSA) of the median nerve and electrophysiologic findings in diabetic patients. Methods: Sixty diabetic patients, 30 patients with carpal tunnel syndrome (CTS) and 30 healthy volunteers participated. The participants were divided into 4 groups: Control Group; Group I, diabetic patients without diabetic polyneuropathy (DPN); Group II, diabetic patients with DPN; and Group III, patients with CTS. Group II was subdivided into II-1 and II-2 according to DPN severity. The median nerve CSA was measured at 4 levels, and the wrist-to-forearm ratio (WFR) was calculated. Results: The median nerve CSAs were larger in Group II than in Group I and the Control Group. There were significant differences in the CSA between Group I and Group II-2 and between Group II-1 and II-2. There was no significant difference in the WFR among these groups. The CSAs at the wrist levels and WFR were significantly greater in Group III. Conclusions: The median nerve CSA was greater in patients with DPN and was related to DPN severity. Diffuse increase in median nerve CSA without change in the WFR might be compatible with DPN. Ultrasonography could be applied for the diagnosis of DPN, especially in advanced cases. Significance: Ultrasonography might have value in the differential diagnosis of DPN and entrapment neuropathy.