Frequently Asked Questions (FAQ)

Coronary artery disease is a disease in which a substance called plaque builds up in the coronary arteries, which deliver oxygen-rich blood to the heart. The buildup of plaque narrows the arteries and thus reduces blood flow to the heart.

Reduced blood flow may cause chest pain (angina) and potentially a heart attack. Injured heart muscle can be permanently damaged if the coronary arteries stay blocked for too long. If there is a problem with your heart, it is important to find out about it as soon as possible.

MPI stands for myocardial perfusion imaging. The “myocardium” is your heart muscle. “Perfusion” refers to blood flow. And “imaging” is exactly what it sounds like, taking pictures. So, myocardial perfusion imaging is basically taking pictures of the blood flow to your heart. MPI is also called a cardiac nuclear stress test. It is a commonly used test that provides detailed images that can be used to diagnose and assess coronary artery disease.

Except for a small needle (catheter) that will likely be placed in a vein (IV) in your arm at the start of the test, MPI is a noninvasive test. That means it takes place outside of your body and does not involve surgery of any kind. You will probably stay awake and alert the entire time. A small amount of radioactive fluid, called a tracer, will be injected into your bloodstream through the catheter during the MPI test. This tracer helps the doctor see the blood flow to your heart.

Yes. Remember, radiation is always around us, from computers to wireless technology. Your doctor will make sure this is an appropriate test by looking at the amount of radiation you will be exposed to compared to your risks for heart disease. When it has been determined to be an appropriate test, not having this test may put you at a higher risk than having it done.

Yes. A special camera will take pictures of your heart once the tracer moves through your arteries. Depending on the type of test, you may be required to have 2 sets of pictures taken by the camera at 2 different times (either later that day or even the next day). These pictures give doctors detailed information about blood flow into your heart. They might see that some areas of your heart are not getting all the oxygen and nutrients they need. This information will help your doctors decide what steps should be taken next.

Yes. Your MPI test will be done under the supervision of your heart imaging team, which may consist of a cardiologist, a certified technologist, a radiologist, and/or a registered nurse. In addition to the catheter, electrocardiograph (ECG) leads will be placed on your upper body, and a blood pressure cuff will be used to check your blood pressure. These are all normal monitoring procedures during the test.

Exercise is conducted to evaluate how your heart responds to the increased need for more blood. Arteries that have no plaque will dilate to allow more blood to flow to the heart whereas diseased arteries will not.

There are any number of reasons why someone may be unable to undergo an exercise stress test. Some of these include certain heart conditions, restrictive airway disease, and muscular abnormalities. If you are unsure of your exercise capability, your doctor may suggest MPI testing with exercise, then switch to pharmacologic stress if deemed necessary and appropriate.

Lexiscan (regadenoson) injection is an option. Lexiscan is a prescription drug given through an IV line that increases blood flow through the arteries of the heart during a cardiac nuclear stress test. Lexiscan is given to patients when they are unable to exercise adequately for a stress test.

Lexiscan is a prescription medication given through an IV line that increases blood flow through the arteries of the heart during a cardiac nuclear stress test. Lexiscan is given to patients when they are unable to exercise adequately for a stress test.

You may be lying down on a hospital bed or sitting in a chair when you receive Lexiscan. A nurse or other lab professional will inject Lexiscan, and then the tracer, through the catheter that is already in your arm. It’s important to understand that, whether you exercise on a treadmill or receive Lexiscan, the goal is the same: to increase blood flow to your heart so the tracer is completely distributed throughout your heart for imaging.

The most common side effects that occurred in clinical trials of Lexiscan were shortness of breath, headache, flushing, chest discomfort or chest pain, dizziness, nausea, abdominal discomfort, a metallic taste in the mouth, and feeling hot. Most common side effects began soon after receiving Lexiscan and went away within 15 minutes, except for headache, which resolved in most patients within 30 minutes. You will be monitored before and after administration of Lexiscan for any side effects that require treatment. Such side effects are expected, so be sure to tell the physician or lab personnel how you’re feeling. Remember, these effects usually go away within minutes. After you receive Lexiscan, you’ll be ready for the images to be taken between 1-2 hours later.

For the best possible images of your heart, just do your best to relax and stay still. The goal is to be sure you are as comfortable as possible during the procedure. If you received Lexiscan (regadenoson) injection, you may still be feeling its effects when you’re ready for the images to be taken. During the imaging part of the test, you’ll likely rest on your back with your arms above your head. The camera will take images of your heart for about 15-30 minutes. It’s very important you’re comfortable so you can be as still as possible for the camera to produce the best images. The camera is large, but don’t worry. It shouldn't touch your body, and it doesn’t hurt.

One set of images will usually be taken after the treadmill exercise or after you’ve received pharmacologic stress. You may have another set of images taken while you’re at rest. Comparing these 2 sets of images allows your doctor to see if any parts of your heart are not getting enough blood.

A nuclear cardiologist or radiologist will usually look at the pictures of your heart to look for areas that might not be getting enough blood. They will likley discuss the images with the doctor who ordered the test, who may be your cardiologist or your primary care doctor. When you meet with your doctor, you’ll probably discuss the test results and decide what steps to take next. These may include some simple lifestyle changes, new medications, or more testing.

Be sure to discuss with your doctor which food and drinks to avoid before the test. As a rule of thumb, you should not consume foods, drinks, or medications that contain caffeine for at least 12 hours before the test, including decaffeinated products. This includes coffee, tea, chocolate and cocoa products, soda, including those labeled "caffeine-free," diet supplements and energy drinks. You should also not take medications that contain aminophylline, theophylline, or dipyridamole. View a short list of what not to eat or drink before your test.