Validation of standing cone beam computed tomography for diagnosing subchondral fetlock pathology in the Thoroughbred racehorse.
Authors: Curtiss Alexandra L, Ortved Kyla F, Dallap-Schaer Barbara, Gouzeev Sergei, Stefanovski Darko, Richardson Dean W, Wulster Kathryn B
Journal: Equine veterinary journal
Summary
# Editorial Summary: CBCT validation for fetlock subchondral pathology Subchondral bone lesions in Thoroughbred fetlocks are recognised as precursors to catastrophic injury, yet early detection remains challenging; this study evaluated whether standing cone beam computed tomography (CBCT) could reliably identify these lesions compared to the gold-standard fan beam CT (FBCT). Twenty-five metacarpo-/metatarsophalangeal joints from racehorses were imaged using both modalities and independently assessed by an imaging specialist and surgical specialist, with measurements analysed for consistency between observers and imaging types. Both CBCT and FBCT demonstrated strong interobserver agreement (Pearson correlations of 0.73 and 0.77 respectively, with concordance averaging <0.3 mm difference), and crucially, the two imaging modalities showed equivalent diagnostic capability (mean correlation 0.72), validating CBCT as a reliable alternative. The practical advantage is significant: standing CBCT offers a non-invasive option for in-situ assessment of fetlock architecture without general anaesthesia, potentially enabling routine screening protocols to detect early-stage pathology before clinical signs emerge and allowing evidence-based intervention strategies. For equine professionals involved in performance assessment, this technology could prove invaluable for identifying at-risk individuals, tracking lesion progression longitudinally, and informing decisions about training modification or targeted therapeutic intervention.
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Practical Takeaways
- •Standing CBCT is a reliable tool for detecting early subchondral bone pathology in racehorses, enabling intervention before more serious injury develops
- •CBCT provides equivalent diagnostic information to traditional fan beam CT with better concordance between observers (0.07 mm vs 0.28 mm), improving clinical confidence in lesion identification
- •When evaluating fetlock pathology in racing Thoroughbreds, clinicians should be aware that small lesions may show variable detection between imaging specialists and should consider follow-up imaging when clinical suspicion is high
Key Findings
- •Interobserver CBCT correlation was significant for 21 of 25 variables (Pearson R mean 0.73) with excellent concordance (0.07 ± 1.90 mm average difference)
- •FBCT and CBCT showed significant intermodality correlation and concordance for all variables when interpreted by radiologist (Pearson R mean 0.72, average difference 0.21 ± 0.47 mm)
- •Standing CBCT demonstrated validity as a diagnostic modality for identifying subchondral bone lesions in Thoroughbred fetlocks
- •Inconsistent agreement was noted for small lesions in specific categories, representing a limitation of both imaging modalities