Soft tissue- and bone-phase scintigraphy for diagnosis of navicular disease in horses.
Authors: Trout, Hornof, O'Brien
Journal: Journal of the American Veterinary Medical Association
Summary
# Editorial Summary: Scintigraphy for Navicular Disease Diagnosis Navicular disease remains diagnostically challenging when clinical signs don't align with radiographic findings, prompting investigation into whether nuclear scintigraphy could improve detection rates. Trout and colleagues compared radiography alone against soft tissue- and bone-phase scintigraphy (or both modalities combined) across 14 sound horses and 35 with suspected navicular disease of varying severity. Whilst radiography and scintigraphy showed comparable specificity for confirming navicular disease when positive, scintigraphy demonstrated substantially greater sensitivity—crucially identifying lesions in cases where radiographs appeared normal, suggesting it detects earlier or different pathological changes than conventional imaging. The diagnostic yield improved significantly when both techniques were interpreted together, particularly in horses where radiographic appearance was inconsistent with clinical lameness; soft tissue-phase and bone-phase results generally correlated well, indicating they detect overlapping pathology. For practitioners managing suspect navicular cases—particularly where lameness is localised to the caudal foot but radiographs remain inconclusive—scintigraphy warrants consideration as an adjunctive diagnostic tool to guide targeted treatment and improve prognostic accuracy.
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Practical Takeaways
- •When clinical signs of navicular disease are present but radiographs appear normal, scintigraphy should be considered as it detects lesions radiography misses
- •Use radiography and scintigraphy together for most reliable diagnosis rather than relying on either modality alone
- •Both soft tissue-phase and bone-phase scintigraphy typically give similar results, so either phase can contribute diagnostically
Key Findings
- •Scintigraphy demonstrated greater sensitivity than radiography for detecting navicular disease lesions
- •Specificity of radiography and scintigraphy were nearly equal in revealing signs of navicular disease
- •Combined radiographic and scintigraphic evaluation achieved the greatest sensitivity and specificity
- •Scintigraphy revealed lesions not detected by radiography, particularly improving diagnostic accuracy when radiographic findings were inconclusive