Shear wave elastography in the assessment of gastrocnemius spastic muscle elasticity: influences of ankle position and muscle contraction.
Marine Devis, Frédéric Lecouvet, Thierry Lejeune and 1 others
PMID 39679798WHAT IT FOUND
Ultrasound stiffness readings were higher in the affected calf than the less-affected calf when the ankle rested.
Stretching or contracting the calf changed the readings, so use a neutral resting position for comparison.
Key findings
01With the ankle at rest, shear wave velocity was significantly higher in the affected gastrocnemius muscles than in the less-affected side. The affected side was stiffer.
02Passive dorsiflexion and muscle contraction raised shear wave velocity, and the side difference seen at rest was not the same in those positions.
03In the resting position, repeat measurements were consistent. The paper reported minimum detectable changes of 18% for the lateral calf and 22% for the medial calf at the longer interval.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The sample was small and from one centre, so the results may not apply to all people with neurological spasticity. All measurements were done by one physician, so other clinicians may not get the same results. Freehand ultrasound can be affected by probe pressure, even though the researchers averaged measurements. Muscle is not uniform in all directions and has viscous properties, so shear wave assumptions may not fully hold. The study did not test whether ultrasound stiffness predicts treatment response or function, and correlations with clinical spasticity measures were weak or absent.
Declared interests
No financial conflicts were declared. Funding was from the Fund for Research Training in Industry and Agriculture (FRIA).
The easy way to misread this
Do not conclude that ultrasound stiffness measurement is ready to guide treatment decisions. It was tested only in a small observational group, it did not agree with the hand-held stiffness device or most clinical spasticity and function measures, and no treatment was given or evaluated.