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Updated: Mar 1, 2026

Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease
Published on: December 18, 2016
Quantitative sonographic assessment of myotonia
Alon Abraham1, Ari Breiner1, Carolina Barnett1
1Ellen and Martin Prosserman Centre for Neuromuscular Diseases, Division of Neurology, Department of Medicine, University Health Network, University of Toronto, Toronto General Hospital, 200 Elizabeth Street, Room 5EB-306A, Toronto, Ontario, Canada, M5G 2C4.
Introduction:
This study explores ultrasound imaging for qualitative and quantitative assessment of myotonia.
Methods:
Sixteen patients with myotonia and 16 controls underwent sonographic evaluation of the thenar eminence muscles to assess the relaxation time after muscle percussion.
Results:
The mean time for complete muscle relaxation in patients with myotonia was longer than that of controls. A cutoff of > 0.9 s for myotonia detection had a sensitivity of 88% and a specificity of 100%. The interrater reliability was moderate for qualitative assessment but was high for quantitative assessment. The relaxation time did not correlate with the number of trinucleotide repeats in patients with myotonic dystrophy.
Discussion:
Sonographic evaluation for the presence of myotonia is feasible, sensitive, and specific but does not correlate with disease severity in myotonic dystrophy. Muscle Nerve 57: 146-149, 2018.
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