Ultrasound elastography – A pilot study to examine muscle stiffness

Purpose: As an innovative, noninvasive technique ultrasound elastography allows to assess the elasticity of tissue. The aim of this study was to evaluate strain elastography as a reliable method in different groups of muscles; determination of muscle elasticity in young adults at rest and after exercise and to compare the results with data of children. Subsequently, the elasticity of muscles in children with cerebral palsy will be examined before and after the treatment with botulinum toxin A.

Material and methods: Elastography of the M. biceps brachii, quadriceps femoris, and gastrocnemius lateralis was obtained at rest and after standardized exercises in 11 female and 11 male healty yound adults (Ages 20 – 30 years) by using the iU 22 ultrasound device (Philips) with a linear transducer (L12 – 5 MHz). Anamnestic data were collected by using standarized questionnaires.

Results: By analysing a five-point colour scale post exercise muscle elasticity increased significantly only in the M. biceps brachii (p < 0.05). The deformation ratio of fatty and muscle tissue showed a significant difference in the M. biceps brachii and the M. quadriceps femoris (p < 0.05) after standardized exercises. There were no significant gender-, age- and BMI-related differences in postexercise muscle elasticity.

Conclusion: In this pilot study strain elastography was able to show differences in muscle elasticity between rest and after activity. In a next step children with cerebral palsy will be evaluate before and after the injection of botulinium toxin A. It is to be expected that the elasticity in the muscles will increase after the injection.