About your myocardial perfusion imaging test
If your doctor has recommended a heart scan or a stress test with nuclear imaging, you will undergo a myocardial perfusion study with nuclear imaging. This may also be called a heart scan or a SPECT imaging study. This is a unique modality of medical testing because it provides a nuclear cardiologist with information about both the structure and function of the heart. Nuclear imaging procedures identify abnormalities very early in the progress of a disease, often before other diagnostic tests can identify the same problems and before serious symptoms occur. The pictures from the perfusion study let us look at the blood flow in the arteries leading to your heart and also how well the heart is beating.
If you are able to exercise, you will walk on a treadmill. The exercise will start slowly and increase in both speed and incline every three minutes. Your heart will be monitored continuously through the exercise portion of the study and your blood pressure will be checked several times by the technologist. If exercise is difficult for you, a medication will be used to increase the blood flow to the heart. This is a very short acting medication and may occasionally cause symptoms such as hot flashes or flushing and nausea and headache. The symptoms resolve very quickly after the medication is stopped and are not dangerous.
The nuclear perfusion study is noninvasive and painless. There is a very small amount of nuclear or radioactive material used in the study. The material is referred to as a radiotracer or radiopharmaceutical. The radiotracer behaves in the body as if it were potassium, one of the most common electrolytes in the body. This property allows the radiotracer to concentrate in the heart in the distribution of the blood flow and to be eliminated a short time later by the kidney. The tracer gives off energy which passes through the body and is detected by a special camera called a gamma camera. Some people have concerns about exposing themselves to a radioactive material. The radiotracers that we use have been used for many years in thousands of patients and are considered safe. Our lab endeavors to administer the lowest possible dose of radiation. The dose received by most patients is similar to what they are exposed to by natural background radiation (such as the sun) over a 2-3 year period.
During the test
You will lie on an examination table under the gamma camera. You will be positioned under the camera for a variable amount of time while the camera takes a series of pictures. Because the pictures are taken at a constant rate, it’s important to keep still.
The average imaging time is less than one hour.
A computer connected to the camera detects the radiation coming from the body organ being examined and forms a series of images. These images are interpreted by the nuclear cardiologist who will identify abnormalities in either structure or function of the heart. The results of the study is usually available by the evening of the test and will be communicated to your doctors the following day.