Quantitative muscle ultrasound in upper extremity mononeuropathies.

Introduction We assessed the potential use of quantitative ultrasound (QUS) in the evaluation hand muscles affected by upper extremity mononeuropathies. Methods The gray scale levels (GSLs) of abductor pollicis brevis (APB), abductor digiti minimi (ADM), and first dorsal interosseous (FDI) of 30 healthy and 30 upper extremity mononeuropathy patients were measured and compared with standard electrophysiological values. Results Mean GSL was elevated in 34 APBs of carpal tunnel syndrome patients and 18 FDIs of ulnar neuropathy patients (e.g., FDI mean GSL (interquartile range) 31.5 (27.3 similar to 43.8) arbitrary units for patients and 24.0(23.0 similar to 29.0) for healthy subjects (P = 0.020)). GSL correlated with motor response amplitudes (Spearman's rho (rho) = -0.39, P = 0.002 in APB, rho = -0.72, P = 0.002 in FDI, and rho = -0.43, P = 0.013 in ADM). The APB GSL correlated with electromyographic severity and disease duration (rho = 0.46, P < 0.001 and rho = 0.45, P = 0.003). Conclusions Muscle QUS may serve as a useful tool in upper extremity mononeuropathy evaluation. Further study of this concept is recommended.