Comparison of radiography and scintigraphy in the diagnosis of dental disorders in the horse.
Authors: Weller R, Livesey L, Maierl J, Nuss K, Bowen I M, Cauvin E R, Weaver M, Schumacher J, May S A
Journal: Equine veterinary journal
Summary
# Editorial Summary: Radiography versus Scintigraphy in Equine Dental Diagnosis A prospective comparison of 30 horses with clinical dental disease and 30 controls revealed fundamental differences in how radiography and scintigraphy detect pathology, with important implications for diagnostic accuracy. Using intravenous 99mTechnetium methylenediphosphonate (99mTc-MDP) imaging alongside standard radiographic projections, researchers found that bone-phase scintigraphy demonstrated excellent sensitivity (95.5%) but moderate specificity (86.4%), whilst conventional radiography showed the opposite profile—excellent specificity (95.0%) but poor sensitivity (51.5%). Significantly, horses with confirmed dental disease showed markedly increased scintigraphic activity over affected teeth compared to their contralateral counterparts, with density ratios of 1.5 or greater identifying pathology whilst maintaining only 1% false-positive diagnoses, though 20% of lesions were missed using this threshold. The combination of both imaging modalities substantially outperformed either technique alone, suggesting that scintigraphy should complement rather than replace radiography when dental pathology is suspected. These findings support integrating metabolic imaging into routine dental diagnostics, particularly where radiographic interpretation is equivocal, to ensure appropriate treatment planning and avoid both missed diagnoses and unnecessary extractions based on radiographic artefacts.
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Practical Takeaways
- •Do not rely on radiography alone to rule out dental disease in horses—it will miss approximately half of cases; combine it with scintigraphy for accurate diagnosis
- •Scintigraphy is essential for identifying which specific tooth is diseased and determining the nature of the pathology, complementing radiographic interpretation of anatomical detail
- •Use a density ratio threshold of ≥1.5 on scintigraphic imaging to minimize both false positives and false negatives when evaluating suspected dental disease
Key Findings
- •Scintigraphy with 99mTc-MDP showed excellent sensitivity (95.5%) but moderate specificity (86.4%) for detecting dental disease
- •Radiography demonstrated excellent specificity (95.0%) but low sensitivity (51.5%), making it poorly suited as a standalone diagnostic tool
- •Combined radiographic and scintigraphic evaluation achieved the greatest diagnostic accuracy for dental disease
- •A density ratio of 1.5 or greater between diseased and contralateral teeth on scintigraphy resulted in only 1% false positives and 20% false negatives