High field magnetic resonance imaging contributes to diagnosis of equine distal tarsus and proximal metatarsus lesions: 103 horses.

This research evaluates the effectiveness of using high-field magnetic resonance imaging (MRI) for diagnosing injuries in the lower hock (distal tarsus) and the upper long bone in the back leg (proximal metatarsus) of horses. It was found that MRI could help identify lesions that were otherwise undetectable by other methods, with the most common findings being osteoarthritic changes.

Research Methodology

• The researchers performed a retrospective analysis, where they examined the medical records from a veterinary imaging center.
• The records were from between the years 2012 and 2014, and they involved MRI examinations of the distal tarsus and proximal metatarsus.
• There were 125 limbs from 103 horses examined retrospectively by two board-certified veterinary radiologists.
• The experts characterized and graded soft tissue and bone changes according to severity. They also recorded patient information such as lameness severity and diagnostic analgesia results.

Main Findings

• The most common findings were osteoarthritic changes in the distal intertarsal and tarsometatarsal joints.
• Other findings included bone marrow lesions, degenerative changes in the small cuboidal bones, subchondral cystic lesions, and intertarsal desmopathy (a disease of ligament attachments).
• Suspensory ligament injuries were found in 53% of the limbs evaluated.
• 47% of the limbs that responded positively to analgesia (pain relief) of the proximal suspensory ligament had more severe lesions in the lower part of the hock (distal tarsus).
• Bone marrow lesions in the third tarsal bone were the only MRI findings that corresponded with the grade of lameness in patients for which a lameness grade was reported.

Lameness Grade and Lesion Severity

• Interestingly, the study found a poor correlation between the grade of lameness and the severity of lesions revealed through MRI. This shows that even if a horse doesn’t seem very lame, it may still have severe lesions.

Conclusion of the Study

• Overall, the study supports the use of MRI for simultaneous examination of the upper long bone in the back leg and the lower hock of horses. This is particularly useful given the challenges in pinpointing lesions using diagnostic analgesia or pain-relief medicine alone.