High-field (3 Tesla) MRI of the navicular apparatus of sound horses shows good agreement to histopathology.
Authors: L. Kottmeier, F. Seehusen, M-J Helweg, K. Rohn, P. Stadler, M. Hellige
Journal: Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association
Summary
# Editorial Summary: High-Field MRI of the Navicular Apparatus Three Tesla MRI systems offer substantially improved spatial resolution and contrast compared to the lower-field systems previously used in equine navicular imaging studies, prompting researchers to characterise how accurately these images correlate with actual tissue architecture. Kottmeier and colleagues examined twenty front feet from sound horses using 3T MRI, then prepared sagittal histopathological sections of the navicular bone and associated ligaments to directly compare imaging findings against tissue reality. Agreement between MRI and histology was very good for cortical bone and trabecular bone, good for fibrocartilage and the distal sesamoidean impar ligament, but only moderate for hyaline articular cartilage and collateral sesamoidean ligaments—notably, hyaline cartilage appeared significantly thinner on MRI whilst fibrocartilage appeared thicker than in actual tissue sections. These findings validate 3T MRI as a reliable diagnostic tool for detailed navicular anatomy in clinical practice, though practitioners should recognise that cartilage measurements may not be directly comparable across different imaging modalities and that quantitative assessment of the collateral ligaments requires cautious interpretation. For farriers, veterinarians, and physiotherapists managing navicular disease, this work strengthens confidence in 3T MRI's capability to detect structural changes and guide treatment decisions, whilst emphasising the importance of understanding imaging limitations when correlating findings to clinical signs.
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Practical Takeaways
- •3 T MRI is a reliable diagnostic tool for assessing navicular bone and ligament pathology, with particular confidence in cortical bone and spongiosa interpretation
- •Be aware that cartilage thickness measurements on 3 T MRI may not directly correlate to actual tissue thickness—hyaline cartilage reads thinner and fibrocartilage reads thicker than histological reality
- •For lameness cases involving the navicular apparatus, 3 T MRI offers superior detail compared to lower field strength systems and can be trusted for structural bone evaluation
Key Findings
- •3 T MRI shows very good agreement with histopathology for compact bone and spongiosa in the navicular region
- •Hyaline cartilage appeared significantly thinner on MRI compared to histological sections
- •Fibrocartilage of the flexor surface appeared significantly thicker on MRI compared to histology
- •3 T MRI provides superior spatial resolution compared to 0.27 and 1.5 T systems for navicular apparatus visualization