Magnetic resonance imaging following regional limb perfusion of gadolinium contrast medium in 26 horses.

This study demonstrates that gadolinium contrast medium can be administered to horses in a low dose via regional limb perfusion to make lesions more apparent during MRI scans.

Introduction and Objective

• This research explored a potential solution to a challenge veterinarians face when using MRI scans to diagnose equine conditions: the quantity of gadolinium contrast medium typically required for systemic administration is prohibitive.
• Contrast media like gadolinium are commonly used in small animal medicine to increase the visibility of irregularities, and to identify the blood supply to such lesions during MRI. The goal of this study was to determine whether a smaller dose of the medium could be effectively administered through regional limb perfusion.

Methods

• The researchers attempted to image the distal limbs (farthest from the trunk) of 26 horses under a prospective clinical study.
• Each horse received a mixture of 5 mL gadopentetate dimeglumine (Magnevist) and 5 mL saline solution, administered through a palmar or plantar digital vein.
• A tourniquet was applied to the mid level of the third metacarpal or metatarsal bone to facilitate contrast absorption.

Results

• Successful contrast enhancement was achieved in 25 out of 26 horses, suggesting the tourniquet may have failed in the one unsuccessful case.
• No adverse effects were observed in any of the horses.

Lesion Detection

• A total of 132 lesions were noted across the horses, with 69 of them showing contrast enhancement. Of these, twelve were only identified post-contrast, substantiating the value of gadolinium contrast in lesion detection.

Limits and Conclusions

• The researchers acknowledge that their sample size is small, and the variability of the identified lesions did not allow for in-depth statistical analysis. Moreover, no histopathology, or microscopic examination of tissues, was performed on healthy horses to establish the normal appearance of the imaged structures.
• Despite these limitations, the study concluded that the regional limb perfusion method is a feasible and effective way to administer gadolinium contrast material. This approach could be a beneficial tool in equine medicine, particularly in identifying lesions in the distal limb, including adhesions, tendinopathy of the deep digital flexor, and areas of neovascularisation.