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Appointments are available Monday through Saturday. Please call (314)996-5170 to schedule your appointment.

What is a Stress Thallium (Myocardial Perfusion Imaging – PMI) Exam?

Myocardial perfusion imaging (Stress Thallium) is a test that uses radioactive substances known as tracers to produce images of the heart muscle. When combined with an exercise or chemical stress test, the myocardial perfusion images help to determine if areas of the heart are not receiving enough blood.
The stress portion can be performed in two ways. You can walk on a treadmill while an EKG machine records the electrical activity of your heart. If you are unable to walk on a treadmill, a chemical stress may be used in place of exercise. The most common drugs used for this are Adenosine and Persantine. These are vasodilators that open blood vessels and are able to mimic the effects of exercise on your body.

Why do doctors recommend a Thallium Stress Test?

This test is especially useful in diagnosing coronary heart disease, which is the presence of blockages in the coronary arteries (the vessels that supply oxygen-rich blood to the heart muscle). It also will help the doctor evaluate irregular heart rhythms, identify areas of the heart that are not receiving enough blood and oxygen and see how quickly the heart recovers after exercise.

How do I prepare for my Thallium Stress Test?

You must not eat anything after midnight on the day before your test. Do not drink coffee, tea, cola, cocoa or any other beverages that contain caffeine for 24 hours before the test. Avoid medications that contain caffeine (such as Excedrin). If you are a smoker, don’t smoke for at least 3 hours before the test. For some patients, certain medications may be stopped one or two days before the test. You doctor will let you know if that is necessary. Bring a list of your medications with you. Do not apply lotions, oils or powders to the chest area and be sure to wear comfortable clothing and walking shoes.

What happens during a Thallium Stress Test?

Before the test begins, you will be given a brief explanation of the procedure. Feel free to ask any questions you may have. An I.V. will then be placed to administer the isotopes during your test.  Thallium, a tracer, will be injected through your I.V. and images of your heart will be taken under a camera for about 15 minutes. When the images are finished, you will be taken into a stress lab where electrodes will be placed on your chest to obtain an EKG. After a resting blood pressure and EKG are taken, you will then walk on a treadmill or receive a chemical to stress your heart. During the stress test another radioactive tracer will be injected through an I.V. in order to take a second set of pictures. After being stressed, you will wait 30 to 45 minutes and then have a second set of images taken. This test may take up to 3 hours.

What happens after a Thallium Stress Test?

After the stress test, there are no restrictions unless otherwise stated by your physician. Your images will be sent to a board-certified radiologist who will interpret the images. A written report will be sent to your physician usually within 24 hours of the test. If you would like to obtain a CD of your images, please ask the technologist or receptionist in the department. If you have any questions, please feel free to call us at (314) 996-5535.