Accuracy of open magnetic resonance imaging for guiding injection of the equine deep digital flexor tendon within the hoof.
Authors: Groom, White, Adams, Barrett
Journal: Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association
Summary
# Editorial Summary: MRI-Guided Injection of the Deep Digital Flexor Tendon Lesions of the distal deep digital flexor tendon (DDFT) within the hoof are commonly identified on MRI in lame horses, and whilst intralesional injection of biological therapeutics such as stem cells or platelet-rich plasma shows considerable promise for tendon healing, accurately delivering these treatments to the site of injury has proven clinically challenging. Groom and colleagues evaluated an open, low-field MRI-guided injection technique on ten cadaver limbs, targeting either the proximal or distal portion of the medial and lateral DDFT lobes using real-time transverse imaging to guide titanium needle placement. Gross pathological examination confirmed successful needle placement in 85% of injections overall (100% for distal targets, 70% for proximal targets), though MRI assessment alone identified successful placement in only 65% of cases, with no significant difference between medial and lateral lobes. The technique demonstrates feasibility for standing injection in clinical practice and could substantially improve the precision of therapeutic delivery to DDFT lesions; however, the study's reliance on cadaver tissue with normal tendons means results may not directly translate to diseased, compromised tendon in live patients, where tissue architecture and accessibility may differ considerably. Practitioners considering MRI-guided injection should recognise that distal lesions appear more reliably targetable than proximal ones, and that post-injection imaging confirmation remains necessary to verify accurate placement before claiming treatment success.
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Practical Takeaways
- •MRI-guided injection of DDFT lesions within the hoof is technically feasible and achieves high accuracy, offering a new option for therapeutic injection of difficult-to-access distal tendon lesions
- •Distal injection locations (adjacent to navicular bone) show higher success rates than proximal locations, which should inform injection targeting strategy
- •This technique could enable standing patients to receive intralesional biologic therapeutics for DDFT healing without general anesthesia, though cadaver validation limits current clinical applicability
Key Findings
- •MRI-guided injection of the distal deep digital flexor tendon within the hoof achieved 85% success rate on gross section evaluation (70% proximal, 100% distal)
- •MRI evaluation showed 65% success rate for the same injections (60% proximal, 70% distal)
- •No significant difference was found between success rates for medial versus lateral lobe injection
- •The technique is feasible for use in standing patients with open low-field MRI guidance