Myocardial Perfusion Imaging
Myocardial Perfusion Imaging is a non-invasive procedure which evaluates the blood flow (perfusion) through the coronary arteries to the heart muscle using a radioactive tracer. The test is done at rest and is usually requested because the ability to exercise on a treadmill is limited. Small electrode patches are placed on the patient’s chest which allows continuous ECG monitoring during the test and intravenous access is necessary. The nuclear tracer (Rubidium-82, Technetium (99mTc) sestamibi) is administered via the vein and a rest image of the tracer uptake into the heart muscle is obtained using a PET scanner. The heart will then be “stressed” (exercised) with a pharmacological agent, either adenosine or persantin. The nuclear tracer is re-administered at peak stress to obtain the stress images of the heart muscle. Areas of the heart muscle with inadequate arterial blood supply, due to blockages, will show on the stress images.
24-hours before the procedure, patients need to avoid any products that contain caffeine (tea, coffee, milo, cocoa) and any products that contain chocolates. A light meal is allowed 1 hour prior to the test. The use of stress agents, adenosine or persantin is generally avoided in patients with asthma. There are no side effects of the Rubidium-82 and radiation exposure is minimal due to its short half-life.
Myocardial Perfusion Imaging takes about 1 hour if Rubidium-82 is used and normal activities and diet can be resumed soon afterwards. The report is generated by a cardiologist.