Shear-wave elastography of the ulnar collateral ligament of the elbow in healthy volunteers: a pilot study.

ABSTRACT

OBJECTIVE: To estimate the intra-observer repeatability of shear wave elastography in the UCL of the elbow, and to compare shear wave velocities between dominant and non-dominant arms. MATERIALS AND METHODS: Twenty elbows in ten healthy volunteers were evaluated [five males, five females; mean age, 31.8 ± 10.3 years]. Shear wave velocity was measured on three separate days during the span of 1 week utilizing a linear 18-MHz transducer. Elastograms were obtained until ten ROIs were drawn, not drawing more than two ROIs on any elastogram. Elastograms were considered diagnostic if any portion of the UCL was colored in and free of boundary artifacts. Median velocity and interquartile range were recorded. A result was considered reliable if the IQR/median ratio of the ten measurements was < 0.3. RESULTS: IQR/median was < 0.3 in 88% of sessions, although in 28% of sessions fewer than 60% of elastograms were diagnostic. The ICC was 0.05 (95% CI; - 0.18-0.36; poor). Repeatability coefficient (95% limits of agreement) was 1.95 m/s (95% CI; 1.61-2.37 m/s). Mean velocity in dominant arms was 5.14 ± 0.53 m/s and 5.24 ± 0.39 m/s in non-dominant (p = 0.558). CONCLUSIONS: Mean shear wave velocity was similar between dominant and non-dominant arms. Although repeatability was poor as assessed by ICC, the repeatability coefficient may be a more useful indicator of clinical utility once shear wave velocities in diseased ligaments are explored. Future studies should therefore evaluate velocities in diseased ligaments and develop techniques to improve elastogram quality.