Authors: Spriet M, Espinosa P, Kyme A Z, Phillips K L, Katzman S A, Galuppo L D, Stepanov P, Beylin D
Journal: Equine veterinary journal
Summary
# Editorial Summary: 18F-Sodium Fluoride PET Imaging in the Equine Distal Limb Spriet and colleagues have explored the clinical feasibility of positron emission tomography (PET) using 18F-sodium fluoride (18F-NaF) as a bone-specific tracer in horses—a novel application in equine imaging. Three research horses underwent general anaesthesia for intravenous administration of 18F-NaF (1.5 MBq/kg), with PET scanning of the forefeet and fetlocks performed immediately using a portable scanner, followed by comparison with CT, bone scintigraphy, and MRI acquired under separate sedation episodes. Crucially, 18F-NaF PET identified focal areas of increased tracer uptake at ligamentous attachments, subchondral bone, and the flexor cortex of the navicular bone where conventional imaging modalities showed no abnormalities, and notably distinguished between metabolically active and inactive osseous fragments and new bone formation—a functional distinction unavailable through anatomical imaging alone. The radiation dose was comparable to traditional equine bone scintigraphy, rendering it a practical alternative, though the study's limitation to three horses without histopathological confirmation warrants cautious interpretation. For equine practitioners, this research suggests 18F-NaF PET holds genuine potential for early detection of bone and soft tissue pathology before structural changes become apparent on conventional imaging, potentially transforming lameness investigation and research protocols, particularly where differentiating active from healed lesions proves diagnostically critical.
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Practical Takeaways
- •18F-NaF PET offers complementary diagnostic information beyond conventional imaging (CT, MRI, scintigraphy) for investigating equine distal limb lameness, particularly in detecting early metabolic bone activity
- •The ability to differentiate active from inactive bone lesions may help guide treatment decisions and prognosis in horses with navicular disease and other distal limb pathology
- •This advanced imaging modality is potentially applicable to clinical practice, though currently availability and cost are limiting factors
Key Findings
- •18F-NaF PET imaging was successfully performed in equine distal limbs without complications using a portable scanner
- •PET detected focal uptake in areas where CT, MRI and scintigraphy identified no abnormalities, including ligamentous attachments and subchondral bone
- •18F-NaF uptake distinguished between active and inactive osseous lesions, with uptake present in some but not all fragments and areas of bone formation
- •Radiation exposure rate from 18F-NaF PET was comparable to equine bone scintigraphy