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Published on: January 11, 2019
Quantitative ultrasound of denervated hand muscles
Neil G Simon1,2,3, Jeffrey W Ralph1, Catherine Lomen-Hoerth1
1Department of Neurology, University of California, San Francisco, San Francisco, California, USA.
Introduction:
Presentations to the neuromuscular clinic commonly involve hand muscle denervation, but few studies have evaluated hand muscle ultrasound.
Methods:
Ultrasound studies of abductor pollicis brevis, first dorsal interosseous, and abductor digit minimi were prospectively performed in a cohort of 34 patients (77 muscles) with electromyography (EMG)-confirmed denervation, compared with 58 healthy control subjects.
Results:
In control subjects, muscle thickness was highly reproducible [intraclass correlation coefficient (ICC) = 0.88-0.98], and echogenicity was moderately reproducible (ICC = 0.542-0.686). Age, gender, and body mass index influenced muscle thickness and echogenicity. Ultrasound changes in denervated muscles correlated with the severity of EMG abnormalities. A z-score cutoff of 0 identified denervated muscles with a sensitivity of 100% and 89% for echogenicity and muscle thickness, respectively.
Conclusions:
Hand muscle ultrasound provides a noninvasive method to quantify muscle denervation and may be useful as a screening tool before EMG studies.
