Comparisons of computed tomography, contrast-enhanced computed tomography and standing low-field magnetic resonance imaging in horses with lameness localised to the foot. Part 2: Lesion identification.

This research article outlines a comparative study of three imaging methods: computed tomography (CT), contrast-enhanced computed tomography (CECT) and standing low-field magnetic resonance imaging (LFMRI) in identifying foot injuries in horses. The research found that all three techniques were effective in recognizing different types of lesions, but each method presented its limitations and there was a discrepancy in detection and classification of injuries.

Research Objective and Methods

• The research aimed to study the efficiency of CT, CECT, and LFMRI in identifying lesions in the distal limb (lower part of the leg) of a horse and to document the discrepancy in distribution and classification of these lesions.
• The research worked on identifying lesions on CT and MR images of the horse feet (31 limbs) and compared the findings for concordance using the paired marginal homogeneity test. The distributions of identified lesions were compared using Chi-squared tests.

Research Findings

• The study found that deep digital flexor tendon (DDFT) injuries were quite common and were more effectively detected using CT and CECT than through LFMRI. This indicates the superiority of CT/CECT in certain domains over LFMRI.
• However, lesions that showed only on LFMRI were often distal (near the end of the limb) of the sesamoid (a bone embedded in a tendon), while those identified only on CT/CECT were proximal (near the center of the body) of the sesamoid, indicating the difference in detection capabilities of the techniques.
• The type of lesion also varied depending on the technique used: LFMRI identified core or split lesions, while CT spotted abrasions, core, enlargement, or mineralisation.
• Using contrast-enhanced CT instead of the regular CT increased lesion detection, especially at the tendon insertion point, and exhibited vascular enhancement (increased visibility) in 75% of cases.
• LFMRI and CT/CECT both failed to identify certain types of issues – soft tissue mineralisation and bone oedema (swelling), respectively. Thus, certain shortcomings were found in all studied techniques.

Conclusion

• The study concluded that while all three techniques can detect several lesions, there is a discrepancy in error detection and lesion classification.
• It was suggested that LFMRI, focused only on the podotrochlear apparatus (a part of the foot), might fail to detect lesions of the pastern (a part of the leg above the foot) or soft tissue mineralisation. Similarly, CT may fail to identify DDFT lesions distal to the proximal border of the distal sesamoid.