Quantifying Thermal Patterns Across Canine Body and Limbs.

Abnormal surface patterns revealed in thermal images may indicate the presence of injury, disease, or inflammation in canines. Despite the use of infrared thermography in a laboratory setting, clinical application cannot be fully utilized without understanding isothermic patterns of the canine body. The objective of this study was to identify the thermal pattern of the canine body (Canis lupus familiaris). Rectangular regions of interest (ROIs) were drawn to represent the lateral surface of the torso (ROI 1) and hindquarter (ROI 2). Circular ROIs were analyzed along the limbs to portray joints and its diaphyses. All ROIs were detected through mean surface temperatures (STs). To identify the effect of the coat type, mean STs were categorized by each dog's hair coat type: short coat (SC), curly coat (CC), long coat (LC), and double coat (DC). The interaction between the ST of the ROIs across the body and limbs and were then analyzed using two-way analysis of variance repeated measures (two-way RM ANOVA) and multiple pairwise comparisons. The warmest regions of the body were found ventrally and distally in the abdominal regions of the torso (30.46 °C). Higher ST were found in areas of the hindquarter caudally and distally at the sacral end (30.53 °C). Significant differences in median ST using one-way RM ANOVA on Ranks were observed between body percentage divisions (P < 0.001). In addition, significant interactions between location of the horizontal/vertical divisions and coat types were present (P < 0.001). In general, all dogs exhibited a decrease in temperature distally from the appendicular skeleton. No significant differences were found between joint and diaphyses (P > 0.05). Both SC and CC dogs showed that the decrease in mean ST from the shoulder becomes significant after the shoulder. DC dogs exhibited significant ST lower on the limbs whereas LC dogs did not exhibit a significant trend.