2D-shear wave elastographic features of normal and injured equine superficial digital flexor tendons.
Authors: Guerri G, Bandera L, Straticò P, Palozzo A, Di Nunzio L, Celani G, Varasano V, Vignoli M, Petrizzi L
Journal: Equine veterinary journal
Summary
# 2D Shear Wave Elastography as a Tool for Detecting Superficial Digital Flexor Tendon Injury Superficial digital flexor tendon (SDFT) injuries progressively compromise the mechanical integrity of the tissue, yet early detection remains challenging during routine clinical examination. This prospective observational study evaluated whether two-dimensional shear wave elastography (2D-SWE)—an ultrasound-based technique measuring tissue stiffness—could reliably identify healthy versus pathological SDFTs across 13 clinically sound horses and 17 with naturally occurring SDFT tendinopathy. The healthy tendons demonstrated significantly lower stiffness values at the mid and distal metacarpal levels, with median shear wave velocities of 8.19–8.27 m/s and Young's modulus values of 204–299 kPa, compared to injured tendons measuring 8.47–8.48 m/s and 214–216 kPa respectively; importantly, unaffected contralateral limbs in injured horses differed from both affected limbs and sound controls, suggesting subclinical changes that conventional ultrasonography might miss. The technique demonstrated excellent to good interobserver agreement, establishing it as feasible and reproducible for supplementary diagnostic use. For equine practitioners, these findings suggest 2D-SWE could enhance detection of early tendinopathy and bilateral involvement, potentially enabling more timely intervention, though the relatively small sample size and examination of naturally occurring lesions warrant validation in larger prospective cohorts before routine implementation.
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Practical Takeaways
- •2D-SWE can now be used alongside traditional ultrasound to objectively quantify tendon stiffness changes in horses with SDFT injuries, improving diagnostic confidence
- •Healthy tendons are significantly softer than injured ones; lower stiffness values indicate better mechanical properties, which may have prognostic value for healing and return to work
- •This technique can detect early changes in the contralateral limb before clinical signs appear, potentially enabling early intervention before overt tendinopathy develops
Key Findings
- •2D-SWE demonstrates excellent to good interobserver agreement for assessing equine SDFT
- •Healthy SDFTs exhibit significantly lower shear wave velocity (8.19–8.27 m/s) and Young's modulus (204–299.21 kPa) compared to injured tendons (8.47–8.48 m/s and 214.44–216.03 kPa)
- •Unaffected limbs in horses with unilateral tendinopathy showed intermediate values differing from both healthy and affected limbs at specific metacarpal levels
- •2D-SWE is feasible as a supplementary diagnostic method for detecting and characterizing SDFT tendinopathies based on tissue stiffness measurement