Intramodality and intermodality agreement in radiography and computed tomography of equine distal limb fractures.
Authors: Crijns C P, Martens A, Bergman H-J, van der Veen H, Duchateau L, van Bree H J J, Gielen I M V L
Journal: Equine veterinary journal
Summary
# Editorial Summary Whilst CT imaging has become increasingly available at equine referral centres, the relative diagnostic strengths of radiography and CT for characterising distal limb fractures remain poorly defined. Crijns and colleagues conducted a retrospective review of radiographic and CT images from 27 horses with suspected distal limb fractures, having four observers independently assess predefined fracture characteristics (location, displacement, articular involvement, comminution, fragment number, orientation, width and coalescing cracks) and calculating agreement using Cohen's kappa statistics. Both modalities demonstrated very good agreement amongst observers for fracture identification, and both achieved good intermodality and intramodality agreement for anatomical location and displacement; however, agreement for articular involvement, comminution and fragment number fell to the lower threshold of good agreement. Notably, CT showed superior intramodality agreement compared to radiography for fracture orientation, width and coalescing cracks, though intermodality agreement for these features remained poor to fair. For distal limb fracture assessment, these findings suggest radiography and CT should be considered complementary rather than interchangeable—radiography appears sufficient for basic fracture identification and location, whilst CT provides clearer definition of complex fracture geometry, though neither modality's actual diagnostic accuracy against surgical or post-mortem findings has yet been established.
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Practical Takeaways
- •CT and radiography each reliably identify fractures when used alone, but results may differ between modalities—use both when fracture characterisation is critical for surgical planning
- •Anatomical location and displacement are reliably assessed by either modality; however, fracture orientation and crack identification require CT for consistent interpretation
- •When fine details matter (orientation, width, comminution), CT provides more reproducible results than radiography alone, justifying referral for complex distal limb fractures
Key Findings
- •Both CT and radiography showed very good intramodality agreement for fracture identification, but intermodality agreement was lower
- •Good agreement existed for anatomical localisation and fracture displacement between both modalities
- •Poor to fair intermodality agreement for fracture orientation, width, and coalescing cracks, with CT showing higher intramodality agreement than radiography for these features
- •Agreement for articular involvement, comminution, and fragment number was at the lower limit of good agreement