Thermography is the pictorial representation of the surface temperature of an object. It is a non-invasive technique that measures emitted heat. The circulatory pattern and relative blood flow dictate the thermal pattern, which is the basis for thermographic interpretation. This ability to noninvasibly assess inflammatory change makes thermography an ideal imaging tool to aid in the diagnosis of certain lameness conditions in the horse. In addition, thermography is an excellent adjunct to clinical examination as well as being complementary to other imaging techniques such as radiology, ultrasonography and nuclear scintigraphy.
There are at least three ways in which thermography can be used in an equine veterinary practice. The first is as a diagnostic tool or a physiologic imaging method, where a difference of one degree between two anatomically symmetric regions indicates a region of inflammation. The second method is to enhance the physical examination. In these cases, thermography is used to identify changes in heat and to locate areas of suspicion. Thermography cameras are approximately 10 times more sensitive than the human hand in determining temperature difference; therefore, this method helps the veterinarian identify asymmetry between the horse's anatomical structures. The third method of using thermography is as a preventative measure to enhance training. Thermographic changes occur two weeks before many clinical changes; thus, thermography can be used in a training program to identify subclinical problems so that conditioning alterations can be made to avoid injuries.