Intraarterial contrast-enhanced computed tomography of the equine distal extremity.

The research presents a new method of regional delivery of contrast medium to a horse’s foot. This technique augments the accuracy of computed tomography (CT) scans for assessing soft tissue structures within the hoof capsule. The results reveal a significant increase in the visual clarity of targeted tendons and ligaments. The findings offer a foundation for comparative analysis of horses afflicted with distal extremity injuries causing lameness.

Methods of Research

• The researchers devised a new procedure for regional distribution of an iodinated contrast medium to the horse’s foot. The intent was to enhance the diagnostic worth of CT scans in identifying the soft tissue structures present within the hoof capsule.
• An intraarterial catheter was inserted under ultrasound guidance into the medial palmar artery – located at the level of the carpus. This setting was chosen to sustain a steady-state injection of the contrast medium.
• Two 5mm collimated contiguous acquisition CT scans were performed on ten horses. None of these horses exhibited lameness or radiographic signs of distal sesamoid bone degeneration.
• CT examinations were carried out before and during the regional arterial infusion of the contrast medium at a rate of 2ml/s.

Results and Discussion

• Findings from pre- and post-contrast CT images were used to quantify the cross-sectional area and mean pre- and post-contrast attenuation of the deep digital flexor tendon along with the collateral ligaments of the distal interphalangeal joint.
• Success was met in catheterization procedures without any complications in all of the horses. This reaffirms the feasibility and safety of the method proposed.
• Examination of the tendons and ligaments of interest revealed a significant but small (8 to 20 Hounsfield Unit) increase in attenuation while the contrast medium was sustained. This implies clearer visibility, thus effective diagnosis. This was further supported by a statistical significance of P < 0.05, paired t-test.

Significance of Study

• The research is of considerable importance as it can enhance the diagnostic potentiality of CT. It furnishes a quantitative baseline data tool which can be used for comparison with horses affected by lameness-inducing soft tissue injuries within the distal extremity – injuries that can be alleviated with a palmar digital nerve block. Therefore, not only does it innovate diagnostic methods, but also opens avenues for improved treatment.