Comparison of cone-beam and fan-beam computed tomography and low-field magnetic resonance imaging for detection of palmar/plantar osteochondral disease in Thoroughbred horses.
Authors: Lin Szu-Ting, Bolas Nicholas M, Peter Vanessa G, Pokora Rachel, Patrick Hayley, Foote Alastair K, Sargan David R, Murray Rachel C
Journal: Equine veterinary journal
Summary
# Editorial Summary Palmar/plantar osteochondral disease (POD) of the condyles represents a significant pathological challenge in racehorses, yet optimal imaging strategies for detection remain unclear. Researchers examined 35 cadaver limbs using cone-beam CT (CBCT), fan-beam CT (FBCT), and low-field MRI, comparing all three modalities against macroscopic pathology as the reference standard across 48 lesions found in 70 condyles. Fan-beam CT demonstrated the highest sensitivity for lesion detection (95.8%), though with lower specificity (63.6%), whilst CBCT achieved better specificity (81.8%) at the expense of reduced sensitivity (85.4%); MRI proved less sensitive overall (69.0%) but showed strong correlation with actual lesion width (r = 0.81), rivalling CBCT (r = 0.79) and outperforming FBCT (r = 0.69). Critically, all imaging modalities underestimated lesion dimensions compared to macroscopic examination, suggesting that lesion size on imaging may underrepresent true pathological extent—a consideration when prognosticating athletic soundness. For practitioners, these findings indicate that whilst CT systems excel at detecting the presence of POD, MRI's ability to characterise lesion severity through varying signal patterns may provide additional clinical insight; however, interdependence on modality availability and motion artefact in live horses means imaging selection should be guided by clinical question and local resources rather than by blanket superiority of any single technique.
Read the full abstract on PubMed
Practical Takeaways
- •For detecting POD in racehorses, CT (either cone-beam or fan-beam) is more sensitive than low-field MRI, but CBCT offers a better balance of sensitivity and specificity; fan-beam CT risks overdiagnosis due to low specificity.
- •All imaging modalities underestimate actual lesion size, so clinical correlation and serial imaging are important—lesions are likely larger than imaging suggests.
- •MRI's different signal patterns may provide additional information about lesion maturity or severity beyond simple detection, potentially useful for prognosis and treatment planning.
Key Findings
- •Fan-beam CT showed highest sensitivity (95.8%) but lowest specificity (63.6%) for POD detection compared to macroscopic pathology; cone-beam CT achieved 85.4% sensitivity and 81.8% specificity; MRI showed 69.0% sensitivity and 71.4% specificity.
- •Cone-beam and fan-beam CT demonstrated similar imaging features with moderate inter-modality agreement (κ=0.56); both systems displayed hypoattenuating lesions with surrounding hyperattenuation.
- •All three imaging modalities underestimated lesion width compared to macroscopic examination, with strong correlations for MRI (r=0.81) and CBCT (r=0.79) but moderate correlation for FBCT (r=0.69).
- •MRI signal intensity patterns (hyperintense and hypointense lesions) may indicate pathological status or severity of POD that CT cannot distinguish.