NUCLEAR IMAGING STRESS TEST
This test uses the IV injection of a small amount of a radioactive substance called “Cardiolite” (in certain situations “Thallium” is used instead). A special camera (“gamma camera”) is used to take pictures of the heart at “rest” and after “stress” (usually in two different days). This medication gets to the heart muscle through the coronary arteries. Normally there is uniform uptake of this radioactive substance. However, if there is a blockage in one or more of the coronaries, there will be a “spot” or “defect”. The size, number and degree of “darkness” of these spots will correlate with the number, location, and severity of the coronary artery disease. Therefore, these nuclear techniques provide more accurate and detailed information than that provided by a regular treadmill test. This test is frequently used to evaluate patients with chest pain or after an angioplasty to detect re-blockage of the dilated artery and after coronary bypass surgery to assess the integrity and function of the bypass grafts done.
If the patient cannot exercise, a “chemical stress test” will be used. This involves the use of an IV medication (instead of exercise) that increases the blood flow to the heart (coronary vasodilators, such as adenosine or persantine). Other IV medications such as dobutamine simulate the effects of exercise (by increasing the heart rate and making each heart beat more forceful) can also be used. These types of stress tests are used in patients who cannot exercise such as those with severe lung disease, arthritis, prior leg amputation or stroke, etc.
We have in place state-of-the-art equipment and computer software, which is operated with the strictest quality control, certified by ICANL.