Validation of delayed gadolinium-enhanced magnetic resonance imaging of cartilage and T2 mapping for quantifying distal metacarpus/metatarsus cartilage thickness in Thoroughbred racehorses.

The research article presents a study focused on validating the use of delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) and T2 mapping for accurately measuring the thickness of distal metacarpus/metatarsus (Mc3/Mt3) cartilage in Thoroughbred racehorses. The results show these techniques can deliver reliable measurements when the Mc3/Mt3 cartilage is not in direct contact with proximal phalanx cartilage.

Research Methodology

• The researchers used twenty-four Mc3/Mt3 cadaver samples from six healthy Thoroughbred racehorses for this experiment.
• They acquired images by applying gadolinium-DTPA(2-) post-intra-articular, using short tau inversion recovery (STIR) and proton density weighted (PDw) sequences.
• The team then compared the thickness of the cartilage measured from the obtained images with the thickness seen in histologic images (obtained microscopically).
• The measurements from the histologic images were conducted twice at three different sites by two observers, with a minimum interval of five days between measurements.

Evaluation and Findings

• The histologic cartilage thickness was measured from the articular surface to the bone-cartilage interface, and from the articular surface to the mineralized cartilage interface (famously called the tidemark).
• The study found that intra-observer repeatability was generally good to moderate when using dGEMRIC where Mc3/Mt3 cartilage was not in contact with the proximal phalanx.
• However, in cases where the Mc3/Mt3 cartilage was in contact with the proximal phalanx cartilage, the researchers noted that measurement of cartilage thickness using dGEMRIC STIR and T2 mapping PDw was not reliable.
• The research indicated no significant variation between histologic cartilage thickness and STIR or PDw cartilage thickness at the site where the cartilage surface of Mc3/Mt3 was separated from the proximal phalanx cartilage.

Conclusion

• This study proposes that dGEMRIC STIR and T2 mapping PDw methods can deliver accurate measurements of Mc3/Mt3 cartilage thickness where the cartilage is not directly touching the proximal phalanx cartilage.
• Consequently, these techniques have potential value for veterinary medicine, especially in the assessment and management of racehorses.