Shear wave elastography potential to characterize spastic muscles in stroke survivors: Literature review

Background: Post-stroke spasticity contributes to impairments, disabilities and decline in quality of life. Quantitative measurements of spasticity are needed in order to assess the impact of specific treatments and to choose the more accurate technique for each patient. The aim of this review is to examine the use of shear wave ultrasound elastography as a quantitative tool for monitoring biomechanical muscle properties such as stiffness and to determine whether it is a reliable method to assess spastic muscle in stroke survivors. Methods: Studies were sought from Academic Search Complete, CINAHL, PubMed/Medline, Scopus and SportDiscus with the following keywords: shear wave elastography, spasticity, stiffness, elasticity, hardness, stroke, cerebrovascular accident, cerebral vascular event and transient ischaemic attack. Titles and abstracts were screened, and relevant full-text articles were retrieved for further review. Findings: Of the 76 screened studies, nine captured elastography data of the spastic biceps brachii (n = 6) or the plantar flexors (n = 3) with stroke victims. All consulted studies had a different way of utilizing this technology which was expected considering no guidelines had been developed. Shear wave speed values obtained are compared and discussed with clinical measures. Reliability of the devices is also discussed. Interpretation: Shear wave ultrasound elastography can provide useful quantitative information on the mechanical properties of the spastic muscles in post-stroke patients. Nevertheless, new studies using common terminology and parameters are needed to develop reliable methods that could help in assessing treatment efficiency.