Mapping tendon stiffness: Two-dimensional versus point shear wave elastography

To date, no study has investigated the comparability between point shear wave elastography (pSWE) and 2D-shear wave elastography (2D-SWE) in assessing patellar tendon (PT) stiffness. In addition to comparing shear wave velocities, this study also evaluated intra- and interrater reliability, as well as measurement time.

Forty healthy subjects (20 females, 20 males; age: 23.3 ± 2.4 years, BMI: 22.46 ± 2.23 kg/m²) were recruited as participants. Each participant underwent a standardized multimodal ultrasound protocol that included B-mode ultrasound (B-US), Color Doppler ultrasound (CD-US), and a shear wave elastography (SWE) examination of the bilateral patellar tendon using both pSWE and 2D-SWE. Stiffness values and examination times were recorded. Intra- and interrater reliability were assessed across two different measurement time points with two investigators for both pSWE and 2D-SWE.

Elastography values were slightly higher for pSWE compared to 2D-SWE (pSWE: 4.02 ± 1.07 m/s, 2D-SWE: 3.82 ± 0.73 m/s; p < 0.001). 2D-SWE10 measurements took significantly more time than pSWE (2D-SWE10: 69.89 ± 13.46 s vs. pSWE: 54.85 ± 8.34 s, p < 0.001). However, the time required for 2D-SWE1 was significantly shorter than for pSWE (2D-SWE1: 47.20 ± 8.23 s vs. pSWE: 54.85 ± 8.34 s, p < 0.001). Both interrater and intrarater reliability reached excellent levels for all SWE measurements, with the highest interrater and intrarater ICC values obtained for 2D-SWE1.

This is the first study to evaluate and compare pSWE and 2D-SWE in the assessment of patellar tendon stiffness. These findings could have important implications for the clinical use of musculoskeletal SWE, providing insights into measurement time, reliability, and the potential benefits of using 2D-SWE in clinical practice.