Preliminary study of proton magnetic resonance spectroscopy to assess bone marrow adiposity in the third metacarpus or metatarsus in Thoroughbred racehorses.
Authors: Hewitt-Dedman Charlotte L, Kershaw Lucy E, Schwarz Tobias, Del-Pozo Jorge, Duncan Juliet, Daniel Carola R, Cillán-García Eugenio, Pressanto Maria Chiara, Taylor Sarah E
Journal: Equine veterinary journal
Summary
Bone marrow adiposity—the accumulation of fat within bone marrow spaces—may serve as a marker of bone quality and fracture risk, yet this relationship remains poorly characterised in racehorses. Hewitt-Dedman and colleagues employed proton magnetic resonance spectroscopy (¹H MRS) to quantify fat content within the third metacarpal and metatarsal bones of 18 limbs from Thoroughbreds, comparing their findings against bone mineral density measurements from CT imaging and histological grading of bone sclerosis. The key observation was a moderate negative correlation between bone mineral density and fat content in both the lateral condyle and proximal bone marrow regions (r = -0.60 and r = -0.50 respectively), suggesting that bones with higher mineral density tend to accumulate less marrow fat; additionally, bones showing greater sclerotic changes on imaging exhibited significant differences in both density and fat content between groups. These findings establish ¹H MRS as a viable quantitative imaging technique for the equine metacarpus/metatarsus and hint that marrow adiposity could eventually help identify horses at elevated fracture risk—though the small preliminary sample size means clinicians must await larger prospective studies before adopting this tool to inform training modifications, remedial shoeing, or rehabilitation protocols for at-risk individuals.
Read the full abstract on PubMed
Practical Takeaways
- •MRS shows promise as a non-invasive imaging tool to assess bone metabolic changes and potentially predict fracture risk in racehorses, though further validation is needed before clinical application
- •The inverse relationship between bone density and marrow fat suggests that increased marrow adiposity may indicate compromised bone quality despite adequate mineral density
- •This technique could help identify at-risk horses earlier than conventional imaging alone, but current evidence is preliminary and limited by small sample size
Key Findings
- •Proton MRS is feasible for measuring fat content in equine third metacarpal/metatarsal bone
- •Negative correlation found between bone mineral density and fat content in lateral condyle (r=-0.60, p=0.01) and proximal bone marrow (r=-0.5, p=0.04)
- •Significant differences in BMD detected between sclerosis grades in condyles on both MRI and CT imaging
- •Fat content differed significantly between sclerosis groups in lateral condyle on MRI and CT