Dual-contrast micro-CT enables cartilage lesion detection and tissue condition evaluation ex vivo.
Authors: Honkanen Miitu K M, Mohammadi Ali, Te Moller Nikae C R, Ebrahimi Mohammadhossein, Xu Wujun, Plomp Saskia, Pouran Behdad, Lehto Vesa-Pekka, Brommer Harold, van Weeren P René, Korhonen Rami K, Töyräs Juha, Mäkelä Janne T A
Journal: Equine veterinary journal
Summary
# Dual-contrast micro-CT for cartilage lesion assessment in equine joints Post-traumatic osteoarthritis represents a significant challenge in equine practice, yet current diagnostic approaches struggle to accurately characterise the severity of chondral defects following injury. Researchers at the University of Helsinki and Utrecht University developed and tested a novel dual-contrast-enhanced computed tomography (dual-CECT) protocol using micro-CT scanning on nine Shetland ponies, creating controlled cartilage lesions (both blunt and sharp grooves) in the radiocarpal and middle carpal joints before subjecting the animals to an 8-week exercise programme; imaging was performed 39 weeks post-injury using a dual-contrast agent comprising ioxaglate (a negatively charged small molecule) and bismuth nanoparticles, with results validated against histological proteoglycan maps. The bismuth nanoparticles remained at the lesion surface due to their size, enabling clear visualisation of defect morphology, whilst the smaller ioxaglate molecules diffused selectively into damaged cartilage tissue, showing a 19 percentage point higher partition coefficient in lesioned areas compared to contralateral controls—findings that correlated well with proteoglycan depletion on histology. This dual-contrast approach simultaneously detects structural cartilage lesions and quantifies tissue degeneration severity, addressing a genuine diagnostic gap in equine orthopaedics and potentially improving clinical decision-making regarding prognosis and intervention timing in post-traumatic joint disease, though translation to in vivo clinical use will require further methodological development.
Read the full abstract on PubMed
Practical Takeaways
- •Dual-contrast micro-CT represents a novel imaging advancement for detecting cartilage lesions and assessing degeneration severity in equine joints, potentially addressing a current diagnostic gap in equine medicine
- •The ability to simultaneously visualize lesion architecture (via bismuth nanoparticles) and tissue biochemical changes (via ioxaglate diffusion) provides complementary information not available with standard imaging
- •This technique was validated only ex vivo; practical application to clinical cases would require development of in vivo protocols and assessment of clinical utility compared to current diagnostic methods
Key Findings
- •Dual-contrast micro-CT successfully detected both blunt and sharp cartilage grooves created in equine joints ex vivo
- •Ioxaglate diffusion into lesioned cartilage was 19 percentage points higher than in contralateral control joints (P<0.001)
- •Bismuth nanoparticles enabled prolonged visual detection of lesions due to their size preventing cartilage diffusion
- •Dual-CECT findings showed good visual agreement with histological cartilage proteoglycan content maps