How is a cardiac nuclear medicine test performed?
The cardiac nuclear medicine test is performed after the patient arrives in the clinic. Basically they are interviewed again making sure that the test is appropriate. The patient has been prepared adequately and appropriately. Then they usually receive what we call a rest scan and that is that the patient is injected interveneously with an appropriate radio tracer. And then, after a few minutes, they are placed into a scanner and images of the heart are obtained. These are called the "rest images." Then after that's finished, a second phase of this study will be performed, and that is the stress portion of the image. In the stress portion the patient is connected to an actual cardiogram by placing electrodes on their body. Depending upon what type of a stress is performed, the patient is prepared appropriately for that. For example, in most common cases, the patient is goes onto a treadmill and they start exercising on a treadmill according to a specific protocol. When the heart rate of the patient gets to some point, which is considered the peak for injection of radio tracer that radio tracer is administered at that point at the appropriate cardiac and stress level. During all this time, the patient's blood pressure is also recorded. The electrocardiogram is dynamically recorded to make sure to look at the electrocardiogram for any systemic changes. After the radio tracer's injected at peak stress, the treadmill, for example, is slowed down and the patient is taken off the treadmill. They relax for some time and then after that, the patient is taken to the camera system for taking additional images. And those additional images are called "stress images." Finally the "stress images" are compared to the "rest images" by a nuclear medicine physician to determine if there was, in fact, a stress induced ischemia, because isocheimal shortage of blood to the heart usually occurs when the heart is under stress and needs to work harder. If the coronary artery that is supplying some area of the heart is narrowed, it is unable to deliver the adequate amount of blood or that radio tracer and that we can see when we compare it to a rest study.
