Sonographic evaluation of the peripheral nerve in diabetic patients: the relationship between nerve conduction studies, echo intensity, and cross-sectional area.

Objective: Early detection of nerve dysfunction is important to provide appropriate care for patients with diabetic polyneuropathy. The aim of this study was to assess the echo intensity of the peripheral nerve and to evaluate the relationship between nerve conduction study results and sonographic findings in patients with type 2 diabetes mellitus.

Methods: Thirty patients with type 2 diabetes (mean +/- SD, 59.8 +/- 10.2 years) and 32 healthy volunteers (mean, 53.7 +/- 13.9 years) were enrolled in this study. The cross-sectional area (CSA) and echo intensity of the peripheral nerve were evaluated at the carpal tunnel and proximal to the wrist (wrist) of the median nerve and in the tibial nerve at the ankle.

Results: There was a significant increase in the CSA and hypoechoic area of the nerve in diabetic patients compared with controls (wrist, 7.1 +/- 2.0 mm(2), 62.3% +/- 3.0%; ankle, 8.9 +/- 2.8 mm(2), 57.6% +/- 3.9%; and wrist, 9.8 +/- 3.7 mm(2), 72.3% +/- 6.6%; ankle, 15.0 +/- 6.1 mm(2), 61.4% +/- 5.3% in controls and diabetic patients, respectively; P < .05). Cross-sectional areas were negatively correlated with reduced motor nerve conduction velocity and delayed latency.

Conclusions: These results suggest that sonographic examinations are useful for the diagnosis of diabetic neuropathy.