Comparison of high-field and low-field magnetic resonance images of cadaver limbs of horses.
Authors: Murray R C, Mair T S, Sherlock C E, Blunden A S
Journal: The Veterinary record
Summary
# Editorial Summary: High-Field versus Low-Field MRI in Equine Lameness Diagnosis When evaluating lame horses, clinicians must weigh the practicality of standing MRI systems against the diagnostic superiority of high-field imaging. Murray and colleagues examined eleven postmortem limbs using both a 0.27T low-field system (designed for standing horses) and a 1.5T high-field system to directly compare their diagnostic capabilities, correlating findings with gross pathology and histology. Whilst both systems successfully identified soft tissue abnormalities in tendons, ligaments and bone, the high-field 1.5T MRI demonstrated substantially greater sensitivity for articular cartilage lesions—detecting pathological cartilage damage that the low-field system missed entirely, though both systems correctly identified normal cartilage. The critical finding is that high-field imaging differentiated the two articular surfaces of joints in most cases, whereas low-field imaging could separate them only at joint margins, representing a significant limitation for detecting early degenerative changes. For equine practitioners, this underscores a diagnostic trade-off: standing low-field MRI offers valuable information on soft tissue structures without sedation, but when subtle or early-stage cartilage pathology is suspected—particularly in chronic lameness cases—high-field imaging provides substantially improved diagnostic precision, justifying the requirement for general anaesthesia where clinical suspicion warrants it.
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Practical Takeaways
- •High-field MRI is superior to low-field systems for detecting articular cartilage lesions and early degenerative changes in lame horses, particularly in the foot and pastern regions
- •Low-field standing MRI systems are useful for screening soft tissue (tendon and ligament) injuries but may miss subtle cartilage pathology critical to lameness diagnosis
- •Consider high-field MRI for cases where cartilage or navicular disease is suspected, despite the need for general anaesthesia
Key Findings
- •High-field (1.5T) MRI detected articular cartilage lesions that were only identified on pathological examination, whereas low-field (0.27T) MRI missed these lesions
- •Both MRI systems detected abnormalities of tendon, ligament and bone found on gross pathological examination, but high-field images showed clearer anatomical detail
- •High-field MRI identified abnormalities in all limbs with navicular flexor fibrocartilage pathology, compared to variable detection on low-field imaging
- •Normal tissue appearance was similar between systems, but anatomical positioning differences and magic angle artefacts varied by field strength