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An imaging stress test combines the exercise stress test (or pharmacological stress) with nuclear images to show the blood flow to the heart muscle. The test uses a radioactive substance which mixes with the blood and enters into the cells of the heart muscle.
If the substance does not reach the heart, it means the arteries may be blocked or there may be damage to the heart.
The radioactive substance is injected two times: first at peak exercise (or pharmacological stress) and a second time when you are at rest. It is performed in conjunction with an exercise stress test or using a medication, such as adenosine or dobutamine, which increases the heart rate similar to exercise.
Before the test –
When you schedule your test, it is important to mention what medicines you take. Ask if you should take any before the test. You should not eat, drink, or smoke, for 4 hours before your test. Because caffeine can interfere with medications we may give you, please not drink coffee, tea, soda or eat chocolate for 24 prior to the test. We recommend that you wear walking shoes and a comfortable two-piece outfit.
During the test -
Similar to an exercise stress test, your heart rate will be monitored during exercise using an ECG. When you reach 80% of your predicted maximum heart rate, a radiopharmaceutical is injected through an IV. After you complete the exercise component of the test, you will then wait 30 minutes while the injected substance localizes in the heart muscle. You will be brought into a room where you will lie on a table to have pictures taken of your heart using special cameras. This usually takes approximately 20 minutes.
After the first set of pictures have been taken, you will be injected the substance one more time and remove the IV. You will be asked to return in 1 hour for another set of pictures. During this time frame, you may eat and drink and take any of your medications as needed. When you return to the nuclear cardiology lab, you will have a set of pictures taken when your heart is “at rest.” This generally takes 20 to 30 minutes. The total time of the test is 3 to 4 hours.
