Ultrasound shear wave elastography - a reliable protocol for the assessment of the stiffness of the supraspinatus tendon.

Abstract

Background: The continued evolution of shear wave elastography (SWE) in the measurement of supraspinatus tendon stiffness can assist in both rehabilitation and surgical monitoring with the potential to improve patient outcomes. It can provide non-invasive, quantitative data of elastic properties of tendons which are altered in the presence of pathological change. This study evaluates the inter- and intra-rater reliability of a standardised SWE assessment protocol of the supraspinatus tendon.

Methods: Shear wave velocity (SWV, m/s) values of 52 healthy, asymptomatic supraspinatus tendons were recorded using SWE. Two raters scanned each tendon on two separate occasions, seven days apart, using a strict protocol.

Results: Intraclass correlation coefficient (ICC) for inter-rater reliability was 0.78. Intra-rater reliability was 0.81 for rater one and 0.89 for rater two, respectively. Minimal detectable change (MDC₉₅) ranged between 1.28 and 1.82 m/s for intra- and inter-rater reliability. Mean SWV values (m/s) for rater one were 9.08 ± 1.44 and 9.29 ± 1.48; and for rater two 8.72 ± 1.35 and 8.87 ± 1.43, for trial one and two.

Conclusion: The results demonstrate reliable SWV measurements between and within raters in the supraspinatus tendon, providing normative values and a protocol which may be utilised clinically.Level of evidence: Level III Diagnostic Study.