Cardiac perfusion scan & bull; hello healthy

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Definition

What is a cardiac perfusion scan?

A cardiac perfusion scan is used to measure the amount of blood in the heart muscle at rest and during exercise. This scan is often done to find out the cause of chest pain. Can be done after a heart attack to see the part of the heart that is not getting enough blood or to find out the extent of damage to the heart muscle due to a heart attack.

During the scan, the camera will take pictures of the heart after a special drug for this test (radioactive tracer) is given through an IV. Tracers travel through the blood and into the heart muscle. As the tracer travels through the heart muscle, an area with sufficient blood flow absorbs the tracer. Areas that cannot absorb the tracer may not be getting enough blood or there may be damage from a heart attack. Two sets of images will be taken during the cardiac perfusion scan. One set is taken while you are resting. Others are taken after your heart has worked hard, either after exercising or after giving medication. The two images will then be compared.

This test is also known by other names, including myocardial perfusion scan, myocardial perfusion imaging, thalium scan, sestamibi heart scan, and nuclear stress test.

When should I have a cardiac perfusion scan?

cardiac perfusion can be used to find out the cause of chest pain, or chest pain that occurs during exercise. This test can also be done to:

• shows the pattern of blood flow to the heart wall
• see if the heart (coronary) arteries are blocked and how severe the condition is
• determine the condition of injury to the heart caused by a heart attack (myocardial infarction)

Precautions & warnings

What should I know before undergoing a cardiac perfusion scan?

There are several reasons why you can't have this test or your test results won't help your condition, including:

• severe heart attack happened recently
• heart inflammation, such as myocardial or sarcoidosis
• injury to the heart muscle (cardiac contusion)
• weakened heart muscle
• tightened heart muscle (myocardial fibrosis)
• severe narrowing of the heart valve
• conditions that make activity difficult, such as lung disease, arthritis, or nerve problems
• medications, such as dipyridamole (Persantine) and pentoxifylline (Trental)
• electrolyte imbalance (especially calcium, potassium, sodium, and magnesium)
• pregnant or breastfeeding (unless it's an emergency)

The test results can be difficult to explain when the scan is performed on women with large breasts.

A drug stress test will be performed instead of an exercise stress test for older adults and people with conditions that have difficulty exercising, such as obesity or chronic obstructive pulmonary disease, peripheral artery disease, spinal cord injury, arthritis, or multiple sclerosis.

Process

What should I do before undergoing a cardiac perfusion scan?

In general, there is not much preparation required before this test. However, you will be asked not to eat or drink anything containing caffeine prior to the test. In some cases, your doctor may advise you not to use the medicine for a few days before the scan. You may also be asked a list of medicines that you used on the day of the test. The local hospital will notify you when these rules apply to you.

How is the heart perfusion scan?

Cardiac perfusion scans are usually performed in a hospital in a radiology department or a doctor's office or an outpatient clinic. This test is performed by doctors and technicians trained in nuclear medicine.

Resting scan

For a resting scan you don't need to do any activity, you will be asked to take off your clothes from the waist up, and you will be given hospital clothes to wear. Electrodes will be attached to your chest to monitor your heart rate. Will be infused into the arm or hand. A small number of radioactive tracers will be placed in the IV.

You will lie on your back on a table with a large camera positioned over your chest. The camera records the tracer signal as it travels through your blood. The camera does not produce any radiation, so you are not exposed to additional radiation during the scan.

You will be asked to stay lying down each time the scan takes place, which can take between 5 and 10 minutes. The camera will move to take multiple pictures from different sides. Several scans will be required.

The entire test will take 30 to 40 minutes, after which you can return to your normal activities.

Stress scan using medication

The stress scan is done in two parts. In many hospitals, the first picture is taken while resting. Then a second picture is taken after being given a drug such as adenosine, which responds to the heart as if it had been exercising. Sometimes a stress scan is done first then a resting scan is done the next day. Drug stress tests are usually used when a person is unable to exercise for some reason.

For this test, you will be asked to sit or lie down on an examination table and you will be given an electrocardiogram (EKG or ECG), which takes about 5 to 10 minutes.

Then you will be given the drug through an IV. You will experience headaches and dizziness and nausea from the drug, but these side effects do not last long. An ECG and blood pressure measurements will be taken in addition. After the drug has reacted (about 4 minutes), a small amount of radioactive tracer (tracer) is given intravenously.

You will wait about 30 to 60 minutes. You will be asked to eat and drink something. Then you will lie on a table to do some scans. The camera records the tracer signal as it travels through your blood. The camera does not produce any radiation, so you are not exposed to radiation during the scan.

Sometimes multiple pictures will be taken after you've rested for 2 to 4 hours. Most people will return to their normal diet and activities after the last scan is done.

Stress scan with exercise

During a stress scan with exercise, your heart rate will be checked with an electrocardiogram (EKG or ECG). Because EKG electrodes need to be attached to the chest to examine the heart, men will usually be bare-chested and women usually wear only bras, or loose shirts.

An exercise stress scan is usually done in two parts. First part, some resting pictures will be taken then some stress pictures will be taken as soon as the exercise is finished. Sometimes a stress scan is done first then a resting scan the next day. In many hospitals, the first resting image is taken using a single type of tracer. The next image is taken using a different tracer after your heart is stressed from exercise.

In this stress test, you will exercise on a treadmill or stationary bike. Your heart rate will be checked during a standard electrocardiography test. Your blood pressure will be checked using a blood pressure device that is placed on your arm. To learn more, take a look at the topic Exercise Electrocardiogram.

You will walk or pedal slowly and at a relaxed pace. Every minute, the speed will be increased. You will exercise until you need to stop or when you reach a heart rate that feels right. At that point, you will be given a different tracer through an IV. You may continue to exercise for an additional 1 to 2 minutes to get the radioactive tracer circulation to work.

You will lie on the scan table. Each scan takes 5 to 10 minutes. The camera does not produce radiation, so you are not exposed to radiation during the scan. Sometimes more pictures will be taken after you've rested for 30 minutes to 4 hours. In some hospitals, you are given a radioactive tracer a few hours after your exercise and before the final shot.

What should I do after undergoing a cardiac perfusion scan?

You should get up slowly to avoid dizziness or lightheadedness after lying on your back during the procedure. You will be instructed to drink enough fluids and urinate more frequently for 24 to 48 hours after the test to remove any leftover radionuclides from your body. Most people will return to their normal diet and activities after the scan is over.

If you have questions related to this test process, please consult your doctor for a better understanding.

Explanation of the Test Results

What do my test results mean?

Test results are usually available within 1 to 3 days. A cardiac perfusion scan measures the amount of blood in the heart muscle at rest and during exercise. The result is:

• normally, if the radioactive tracer evenly flows in your heart muscle
• abnormal, if there is an abnormal tracer absorption section. This indicates that some parts of the heart muscle are not getting enough blood (ischemia). This could mean there is damage to the heart or there is coronary artery disease