Evaluation of the diagnostic accuracy of skeletal scintigraphy for the causes of front foot pain determined by magnetic resonance imaging.
Authors: Quiney, Ireland, Dyson
Journal: Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association
Summary
# Editorial Summary Skeletal scintigraphy reliably detects increased radiopharmaceutical uptake in horses with foot pain, yet its ability to pinpoint the specific cause of lameness remains limited when compared against MRI findings—the focus of this 2018 retrospective study by Quiney, Ireland and Dyson. The researchers analysed 121 front feet from 70 sports and leisure horses that underwent both imaging modalities, with MRI serving as the reference standard for diagnosis. Whilst sensitivity of scintigraphy varied considerably by anatomical region (31.8–76.2%), specificity remained consistently high (84.6–100%), and substantial agreement (κ = 0.77 and 0.74) was achieved for distal phalanx pathology and ungular cartilages respectively; however, when all regions were pooled, overall agreement was only moderate (κ = 0.49). For practitioners, this means scintigraphy should not be relied upon as a standalone diagnostic tool for front foot pain—it effectively rules in osseous and cartilaginous lesions of the distal phalanx but lacks the sensitivity to exclude or identify soft tissue involvement, rendering MRI essential for definitive diagnosis when lameness aetiology remains unclear despite clinical findings.
Read the full abstract on PubMed
Practical Takeaways
- •Scintigraphy is reliable for identifying osseous trauma to the distal phalanx and ungular cartilages, but should not be used alone to diagnose foot pain causes
- •A positive scintigraphic finding is highly specific (low false positive rate), but negative findings do not rule out significant lesions—MRI follow-up is needed for definitive diagnosis
- •Use scintigraphy as a screening tool to localize pain to the foot and narrow differential diagnosis, but combine with MRI for accurate lesion identification and treatment planning
Key Findings
- •Sensitivity of scintigraphy for foot lesions varied by region (31.8-76.2%) but specificity was consistently high (84.6-100%)
- •Substantial agreement between scintigraphy and MRI for distal phalanx palmar processes (κ=0.77) and body (κ=0.74)
- •Moderate agreement for ungular cartilages and chondral ligaments (κ=0.62 for both)
- •When all regions combined, scintigraphy showed only moderate agreement with MRI diagnosis (κ=0.49)