Infra-red emission and 133 Xe-disappearance rate studies in the horse.

This research article investigates whether thermographic imaging of the coronary band can reliably indicate blood flow patterns in horses, comparing heat differences on the hoof with measurements of 133Xe disappearance to assess circulation at rest and after exercise.

Thermographic Screening of Coronary Bands

• The study involved thermographic testing of 46 horses to evaluate infrared (IR) emission patterns at the coronary band. Forty horses showed uniform heat patterns across both forelegs, while six displayed cooler regions on one or both coronary bands, suggesting possible circulatory differences.

133Xe-Disappearance Rate Measurements

• In six horses with normal thermographic patterns, 133Xe wash-out curves were almost identical between the two limbs of each horse, indicating symmetrical blood flow. In contrast, horses with cooler coronary bands showed slower 133Xe-disappearance rates at rest, reflecting reduced perfusion.

Effect of Exercise on Blood Flow

• All horses with initially cooler coronary bands demonstrated a marked increase in 133Xe-disappearance rate after work, suggesting that exercise improved circulation in areas that appeared cooler at rest.

Correlation Between Temperature and Perfusion

• Across 12 horses tested with both methods, the study found a consistent relationship between heat elevation on thermography and increased 133Xe-disappearance rate, supporting thermography as a useful indicator of blood flow changes in the coronary region.