The stress portion of the test is induced by pharmacological agent called Lexiscan. These agents are given through IV to expand or dilate the coronary arteries, similar to what would happen during exercise. Arteries that have become narrowed will not be able to expand as much as normal arteries. Cardiolite, which is a radioactive tracer that does not contain iodine, is given.
The cardiolite travels freely throughout the arteries that the Lexiscan have expanded. Less Cardiolite will go through the narrowed arteries. Once these agents are all entered into the body, you will be placed under a gamma camera, that simply just takes pictures of your heart first at rest and then again after the stress portion. These images will be then used to diagnose and evaluate the supply of blood to your heart muscle.