Blinded Comparison of Palmaroproximal-palmarodistal-oblique and Dorsoproximal-palmarodistal Oblique Radiographic Projections With Contrast Medium in the Navicular Bursa in Dissected Horse Front Feet With Native Radiographs and Gross Pathology
Authors: Christian Staufenbiel, H. Gerhards, Jens Koerner
Summary
# Editorial Summary: Navicular Bursa Contrast Radiography Navicular disease remains a significant cause of chronic forelimb lameness in horses, yet standard radiography and ultrasound often fail to adequately visualise the podotrochlear apparatus, leaving practitioners to choose between expensive advanced imaging (MRI/CT) or empirical treatment. Staufenbiel and colleagues evaluated whether injecting contrast medium into the navicular bursa before radiography could improve diagnostic accuracy by comparing native and contrast-enhanced radiographs in 48 dissected equine forefeet against gross pathology findings as the gold standard, using two different radiographic projections. Contrast-enhanced images demonstrated significantly better correlation with pathological findings than native radiographs alone (kappa values ranging from 0.280 to 0.455 across all techniques), with the combined assessment of all projections yielding moderate correlation (0.556); notably, contrast studies revealed pathology in roughly 21–23% of severely affected specimens that appeared unremarkable on conventional radiographs, though sensitivity remained modest at 41.4%. For practitioners managing suspected navicular disease, bursography warrants consideration as an accessible, cost-effective adjunct when MRI is unavailable or when therapeutic bursa injection is already planned, particularly as a means to either identify occult lesions or confirm suspected pathology—though native radiography alone remains insufficient for ruling out significant disease.
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Practical Takeaways
- •Bursography with contrast medium can detect navicular pathology missed on standard radiographs in approximately 20% of cases, making it useful when MRI is unavailable or when therapeutic injection is already planned
- •Native radiographs alone are insufficient for ruling out navicular disease; consider contrast-enhanced bursography if clinical suspicion remains high despite normal plain films
- •Multiple positive radiographic projections (>2) have excellent specificity (100%) for identifying horses with moderate to severe navicular pathology, supporting diagnosis when present
Key Findings
- •Contrast-enhanced bursography showed improved diagnostic accuracy (kappa 0.455) compared to native radiographs alone (kappa 0.349-0.358) when compared to gross pathology
- •21-23% of moderately to severely diseased feet (gross pathology groups 3-4) showed pathological changes only on contrast-enhanced images with unremarkable native radiographs
- •When more than two radiographic projections showed findings, 100% specificity was achieved for detecting moderate to severe pathology, though sensitivity was only 41.4%
- •Combined evaluation of all radiographic views (native plus contrast-enhanced) showed moderate correlation with gross pathology (Spearman coefficient 0.556, P<0.001)