Does Direct MRI Tenography Improve the Diagnostic Performance of Low-Field MRI to Identify Artificially Created Soft-Tissue Lesions within the Equine Cadaveric Digital Flexor Tendon Sheath?
Authors: Aßmann Anton, Ohlerth Stefanie, Hartmann Silvana, Torgerson Paul, Bischofberger Andrea
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Tenosynovitis affecting the digital flexor tendon sheath remains diagnostically challenging in clinical practice, with ultrasound and contrast tenography currently serving as the primary imaging modalities despite their limitations in preoperative assessment. Researchers evaluated whether intrathecal gadolinium administration during low-field MRI (creating "MRI tenography") could enhance detection of artificially created soft-tissue lesions across four anatomical regions—the superficial and deep digital flexor tendons, manica flexoria, and proximal scutum—in 21 cadaveric digital flexor tendon sheaths containing 118 lesions. Counterintuitively, adding gadolinium contrast provided no significant diagnostic advantage: whilst it marginally improved sensitivity for superficial digital flexor tendon (54% versus 39%) and proximal scutum lesions (50% versus 38%), it actually reduced sensitivity for manica flexoria and deep digital flexor tendon lesions, with both techniques demonstrating comparable specificity (93–100% across all structures). Lesion size emerged as the critical limiting factor, with both MRI protocols struggling to detect smaller lesions, suggesting that sensitivity constraints relate fundamentally to resolution rather than contrast optimisation. For equine practitioners, this finding indicates that low-field MRI offers high specificity for confirming intact structures but cannot reliably exclude small soft-tissue pathology; consequently, negative MRI findings should not exclude DFTS involvement clinically, and conventional ultrasonography with surgical confirmation remains prudent when lesion dimensions fall below the detectability threshold.
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Practical Takeaways
- •Low-field MRI and contrast tenography have high specificity but limited sensitivity for DFTS lesions—negative results are reassuring but positive findings require additional confirmation
- •Lesion size matters: small soft-tissue lesions within the flexor tendon sheath may be missed on imaging, so clinical and ultrasound findings remain critical diagnostic tools
- •MRI tenography with gadolinium does not provide significant added benefit over standard MRI for routine DFTS lesion detection in equine practice
Key Findings
- •Low-field MRI and MRI tenography had high specificity (93-100%) but low sensitivity (32-61%) for detecting artificially created DFTS lesions
- •Intrathecal gadolinium administration did not significantly improve diagnostic performance of low-field MRI for DFTS lesion detection
- •Lesion size was significantly associated with detection success (p = 0.001), with smaller lesions less frequently identified
- •Both MRI and MRIt were most reliable for confirming intact structures rather than identifying pathology