Proximal suspensory desmopathy in hindlimbs: Magnetic resonance imaging, gross post-mortem and histological study.
Authors: Dyson S, Pinilla M J, Bolas N, Murray R
Journal: Equine veterinary journal
Summary
# Proximal suspensory desmopathy in hindlimbs: MRI findings validated through post-mortem correlation Proximal suspensory desmopathy (PSD) in the hindlimb remains diagnostically challenging, and until this 2018 work by Dyson and colleagues, no published research had directly correlated high-field MRI findings with gross and histological post-mortem examination in affected horses. The researchers performed pre-slaughter MRI on 12 limbs from 11 horses with confirmed hindlimb PSD, then conducted detailed gross examination and histological analysis of all suspensory ligaments following humane destruction, using blinded assessment and Bayesian statistical analysis to determine which imaging and post-mortem findings most closely reflected disease severity. Whilst abnormal signal intensity in the ligament's collagenous core was relatively uncommon (2/12 limbs), pathology in surrounding tissues was nearly universal: muscle abnormalities appeared in every limb examined histologically and were the strongest indicator of overall disease burden, adhesions between the ligament and adjacent structures were confirmed in six limbs and suspected in eight on MRI, and signal intensity changes in adipose tissue and muscle homogeneity in both lobes correlated most closely with disease measures. For practitioners, this work provides important reassurance that high-field MRI can reliably detect adhesions—a clinically significant finding often associated with poor prognosis—and emphasises that hindlimb PSD frequently involves pathology beyond the ligament itself, particularly muscular and neural changes that may influence rehabilitation strategies and prognostic counselling.
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Practical Takeaways
- •High-field MRI can detect adhesions in proximal suspensory desmopathy, but findings should be correlated with clinical signs as some MRI-detected adhesions may not be confirmed on post-mortem examination
- •Muscle and adipose tissue pathology is a consistent feature of hindlimb PSD—don't focus solely on collagenous ligament changes when interpreting imaging or assessing prognosis
- •Nerve involvement appears common in PSD (10/12 cases) and may contribute to clinical signs; this should be considered when planning rehabilitation or managing pain
Key Findings
- •Adhesions between the suspensory ligament and adjacent tissues were detected by high-field MRI in 8 limbs but confirmed gross pathologically in only 6 limbs (75% specificity challenge)
- •Abnormal muscle tissue was identified histologically in all 12 limbs and was the strongest correlate with overall disease severity
- •MRI signal intensity abnormalities in adipose tissue (6/12 limbs) and muscle homogeneity changes (11/12 limbs) were the most reliable MRI indicators of disease
- •Collagenous tissue signal abnormalities were rare (2/12 limbs), while nerve changes were observed in 10/12 limbs at gross examination