Repeatability of diagnostic ultrasonography in the assessment of the equine superficial digital flexor tendon.
Authors: Pickersgill C H, Marr C M, Reid S W
Journal: Equine veterinary journal
Summary
# Editorial Summary Ultrasonographic measurement of superficial digital flexor tendon cross-sectional area (CSA) is widely used for monitoring tendon injury and recovery in racehorses, yet the repeatability of this assessment across different operators and equipment had not been rigorously quantified. Pickersgill and colleagues investigated potential sources of measurement variability by having two operators acquire transverse ultrasound images of the SDFT in 16 National Hunt Thoroughbreds, then analysed these images both within and between operators using different analytical equipment. Whilst different operators acquiring images produced no significant variation in CSA measurements, a highly significant difference emerged when different operators performed image analysis (P<0.01), with one operator consistently recording larger values; analytical equipment showed no significant effect except at the most distal tendon level. For clinicians and researchers, these findings underscore that standardising the operator performing image measurement—rather than image acquisition—is critical to reducing confounding variables in ultrasonographic monitoring protocols, particularly when longitudinal comparisons are essential for assessing healing trajectory or making diagnostic decisions.
Read the full abstract on PubMed
Practical Takeaways
- •You can safely have different ultrasonographers acquire images for SDFT examinations without introducing significant measurement error
- •Always have the same person perform the CSA measurements from ultrasound images to reduce variability and ensure consistent results for monitoring tendon healing
- •If conducting serial ultrasound examinations to track SDFT recovery, maintaining continuity in the image analysis phase is more critical than consistency in who operates the ultrasound machine
Key Findings
- •No statistically significant difference in CSA measurements when different operators performed image acquisition (P>0.05)
- •Significant difference (P<0.01) found when different operators undertook image analysis, with one operator consistently returning larger measurements
- •No significant difference in CSA measurements at most distal levels when using different analytical equipment (P>0.05)
- •Interoperator variability during image analysis represents a major source of measurement error in equine SDFT ultrasonography