Measurements of equine foot parameters show limited agreement between radiographs and low-field magnetic resonance imaging.
Authors: Bowkett-Pritchard Constance, Bolt David M, Chang Yu-Mei, Berner Dagmar
Journal: Equine veterinary journal
Summary
# Editorial Summary Radiography remains the gold standard for measuring equine foot conformation, but low-field MRI offers soft tissue visualisation that radiography cannot provide—raising the question of whether these modalities could be used interchangeably for anatomical assessment. Bowkett-Pritchard and colleagues compared measurements from radiographs and low-field MRI scans of nine cadaver front feet, performed with and without hoof wall markers (lead strips for radiographs; water-soaked bandage for MRI), calculating agreement between modalities using intra-class correlation coefficients. Only a handful of measurements showed acceptable inter-modality agreement: founder distance achieved good agreement between radiography and T1-weighted MRI with markers (ICC 0.78), whilst sole thickness and epidermal sole thickness demonstrated good to excellent agreement across multiple MRI sequences when markers were used (ICC 0.80–0.91). Disappointingly, measurements of distal dermal structures showed poor intra-observer repeatability regardless of modality, and many other parameters lacked agreement between radiographic and MRI measurements. For equine practitioners, these findings suggest that radiographs and MRI should be regarded as complementary rather than interchangeable diagnostic tools; if serial monitoring of specific parameters is planned, consistency in imaging modality is essential, and radiographic markers appear unnecessary for measurement accuracy whilst potentially compromising repeatability on radiographs.
Read the full abstract on PubMed
Practical Takeaways
- •Do not assume radiographic and MRI foot measurements are comparable; use the same imaging modality for serial monitoring of individual horses
- •If using hoof wall markers, expect improved consistency for sole thickness measurements but recognize limitations for other parameters like distal phalanx rotation
- •When choosing between radiography and MRI for foot assessment, understand that each modality may visualize and measure structures differently, necessitating modality-specific reference ranges
Key Findings
- •Radiographic and low-field MRI measurements showed limited inter-modality agreement for most equine foot parameters
- •Good agreement was achieved only for founder distance (ICC 0.78), sole thickness (ICC 0.81-0.91), and epidermal sole thickness (ICC 0.80-0.88) when hoof wall markers were used
- •Hoof wall markers improved MRI visualization but did not consistently improve radiographic measurements and sometimes reduced intra-observer repeatability
- •Radiography and low-field MRI are not interchangeable modalities for equine foot assessment