Comparisons of computed tomography, contrast enhanced computed tomography and standing low-field magnetic resonance imaging in horses with lameness localised to the foot. Part 1: anatomic visualisation scores.

This research article aims to compare and contrast the effectiveness of three imaging modalities – computed tomography (CT), contrast enhanced computed tomography (CECT) and standing low-field magnetic resonance imaging (LFMRI) – in visualising the anatomy of the equine foot, particularly in lame horses. The study discovered that the quality of anatomic visualisation varied depending on the method used and the specific anatomical structure being observed.

Methodology

• The researchers evaluated and compared images from 22 horses (31 limbs) experiencing lameness, which underwent CT and LFMRI scans of their feet. CECT images were also reviewed when they were available.
• The deep digital flexor tendon (DDFT) in the horses’ foot was categorised into levels from proximal to distal (A-D).
• The components of the foot anatomy were assigned visualisation scores ranging from Grades 0-3, with higher grades representing better visibility.
• Comparisons between the different imaging techniques were made using the paired marginal homogeneity test, a statistical test used to compare changes in categorical data.

Results

• CT and LFMRI methods were found to have similar visibility scores for the navicular bone, middle phalanx, section B of the DDFT, collateral ligaments of the distal interphalangeal joint, and the collateral sesamoidean ligament of the navicular bone.
• LFMRI resulted in lower visibility scores for the proximal and distal phalanx.
• The distal sections of the DDFT (C-D), the Distal sesamoidean impar ligament, and the synovial structures showed better visualisation scores with LFMRI.
• For CECT images, visualisation scores for the DDFT and the collateral sesamoidean ligament were lowered, while the scores for distal interphalangeal synovium visibility were improved.

Conclusions

• The study underscores that visibility scores and, therefore, the quality of anatomical visualisation, can vary significantly depending on the specific imaging method used and the particular structure of interest within the equine foot.
• This information is crucial in understanding the limitations of different imaging technologies when examining horses’ feet and can guide clinicians in choosing the appropriate method of imaging for their cases.