The use of magnetic resonance imaging for the assessment of distal limb wounds in horses: A pilot study
Authors: Sherlock C., Fairburn A., Lawson A., Mair T.
Journal: Equine Veterinary Education
Summary
# Editorial Summary: MR Imaging for Equine Distal Limb Wound Assessment Penetrating wounds to the equine distal limb present a significant diagnostic challenge, as superficial assessment often fails to reveal the full extent of underlying tissue damage. This pilot study examined whether magnetic resonance imaging could provide additional diagnostic information beyond conventional radiography and ultrasonography in 23 horses with distal limb wounds (excluding solar penetrations). Two ECVDI-diplomated radiologists reviewed low-field MR images alongside existing radiographs and ultrasound studies, documenting abnormalities in bone, soft tissue structures, ligaments and tendons, and noting any image artefacts that affected interpretation. MR imaging proved superior to conventional modalities for detecting both bone and soft tissue pathology: osseous lesions appeared in 26% of cases on MR versus only 17% on radiographs, whilst tendon and ligament abnormalities were evident in 57% of horses on MR compared to 47% on ultrasound. Importantly, radiography detected no bone abnormalities that MR had missed, and MR provided superior characterisation of lesions already identified. Magnetic susceptibility artefacts compromised image quality in 17% of cases, though this remained clinically manageable. Most significantly, MR imaging altered case management in 20 of 23 horses (87%), suggesting it revealed clinically important pathology that would otherwise have been missed. Whilst MR imaging cannot replace radiography and ultrasonography as first-line investigations, these findings suggest that referral for MR assessment of distal limb wounds—particularly when conventional imaging appears inconclusive or prognosis remains uncertain—may substantially improve diagnostic accuracy and guide more informed treatment decisions and prognostication.
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Practical Takeaways
- •MR imaging provides superior soft tissue and bone characterization compared to radiographs and ultrasound for distal limb wounds, revealing pathology that conventional imaging misses and changing treatment plans in most cases
- •While MR imaging should complement rather than replace radiographs and ultrasound, it offers valuable prognostic information for complex distal limb wounds, particularly for tendon/ligament assessment
- •Consider MR imaging when conventional imaging is inconclusive or when treatment decisions hinge on detailed soft tissue evaluation, though metal artefacts may limit image quality in some horses
Key Findings
- •MR imaging detected bone abnormalities in 26% of cases versus 17% on radiographs, with no false negatives on MR
- •Tendon/ligament abnormalities identified in 57% of horses on MR versus 47% on ultrasound
- •MR imaging altered case management decisions in 20 of 23 horses (87%)
- •Magnetic susceptibility artefacts compromised image interpretation in 17% of cases