Factors influencing blood flow in the equine digit and their effect on uptake of 99m technetium methylene diphosphonate into bone.

This research investigates the factors that influence blood flow in a horse’s limbs and how these factors affect the uptake of a particular radiopharmaceutical (99m technetium methylene diphosphonate) into bone. The researchers identified exercise as a positive influence on both blood flow and radiopharmaceutical uptake, while factors such as bandaging and lameness did not have an impact.

Research Methodology

• A sample of 202 horses undergoing routine nuclear scintigraphic examination for symptoms of lameness or poor performance was included in the study.
• The horses were randomly divided into four groups, exploring the effects of bandaging and exercise. These groups were no bandages and no exercise (NB/NE); bandages and no exercise (B/NE); no bandages and exercise (NB/E); bandages and exercise (B/E).
• Forelimbs of horses assigned to bandaged groups were bandaged for at least 16 hours before administering radiopharmaceuticals.
• Horses assigned to exercise groups were made to lunge for 15 minutes before the injection of the radiopharmaceutical.
• The researchers then obtained quantitative values for foot perfusion and the uptake of the radiopharmaceutical into bones from scintigraphic measurements observed during vascular and bone phases of radiopharmaceutical distribution.

Research Findings

• Perfusion (blood flow) of the front feet was classified as good in 60% of limbs, reduced in 21%, and poor in 19%.
• A significant positive correlation was identified between exercise and both the foot perfusion and uptake of radiopharmaceuticals into the bone.
• Bandaging did not exert any effect on either blood flow or the uptake of the radiopharmaceutical.
• A relationship was established between environmental temperatures and both perfusion and the uptake of the radiopharmaceutical into bone.
• Estimation of foot surface temperature using thermography was found to be useful in predicting blood flow in the lower limbs.
• No relationship was determined between a horse’s lameness and the uptake of the radiopharmaceutical into the bone.

Recommendations

The researchers recommend that whenever possible, a horse should be exercised for at least 15 minutes prior to the injection of the radiopharmaceutical, particularly if the scintigraphy is to be performed on the distal parts of the limb.