Quantitative evaluation of biceps brachii muscle stiffness in post-stroke patients using shear wave ultrasound elastography

Objective To quantitatively evaluate the stiffness of spastic biceps brachii muscle (BBM) at different angles of elbow flexion and in different muscle layers by real-time shear wave ultrasonic elastography. Methods From May 1,2019 to January 20,2020,20 patients with post-stroke hemiplegia admitted to the First Medical Center of Chinese PLA General Hospital were included in our study.Of the 20 cases,there were 16 males and 4 females with average age of 53.8 (range,30-75) years.The difference of Young's modulus between the affected BBM and unaffected BBM,BBM at 90° elbow flexion and BBM at 0° elbow flexion,and superficial and deep BBM were compared quantitatively by real-time shear wave elastography. Results The Young's modulus of the affected BBM was significantly higher than that of the unaffected BBM (Md:superficial muscle 57.2 vs 31.0,P<0.01;deep muscle 74.2 vs 32.5,P<0.01) at 0° elbow flexion;the Young's modulus of spastic BBM at 90° elbow flexion was significantly lower than that of spastic BBM at 0° elbow flexion (Md:superficial muscle,39.1 vs 57.2,P<0.01;deep muscle,42.6 vs 74.2,P<0.01);and the Young's modulus of superficial BBM was significantly lower than that of deep BBM (Md:57.2 vs 74.2,P<0.01) at 0° elbow flexion.At 0° elbow flexion,the Young's modulus in the superficial and deep layers of BBM was positively correlated with MAS score (superficial,r=0.612,P=0.004;deep,r=0.732,P=0.000). Conclusion The real-time shear wave ultrasound elastography can evaluate the stiffness of spastic BBM after stroke.