Cardiac Blood Pool Scan
A cardiac blood pool scan shows how well your heart is pumping blood to the rest of your body. During this test, a small amount of a radioactive substance called a tracer is injected into a vein. A gamma camera detects the radioactive material as it flows through the heart and lungs.
The percentage of blood pumped out of the heart with each heartbeat is called the ejection fraction. It provides an estimate of how well the heart is working.
There are two types of cardiac blood pool scans.
Why It Is Done
A cardiac blood pool scan is done to:
How To Prepare
Before having a cardiac blood pool scan, tell your health professional if you:
You may be asked not to eat or drink for a few hours before the test. You should not have any caffeine or smoke for 4 to 6 hours before the test.
If testing will include exercise, you should wear comfortable shoes and clothing.
Many medicines may affect the results of this test. Be sure to tell your health professional about all the nonprescription and prescription medicines you take.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).
How It Is Done
A cardiac blood pool scan usually is done in a hospital by a radiology or nuclear medicine technician. Most people do not have to stay overnight in the hospital.
Before the test
You will need to remove any jewelry that might interfere with the scan. You may need to take off all or most of your clothes. You will be given a cloth or paper gown to use during the test.
During the test
You will lie on an examination table beneath the gamma camera. Electrocardiogram (EKG, ECG) electrodes are attached to your chest so that the electrical signal of your heart can also be detected. Then the camera, which is a round metal instrument about 3 ft (1 m) wide, will be positioned close to your body. If you are cold or uncomfortable lying on the table, ask the technician for a pillow or blanket. The camera may be positioned in different places across your chest to record different views of your heart.
The technician cleans the site on your arm where the radioactive tracer will be injected. An elastic band, or tourniquet, is then wrapped around your upper arm to temporarily stop the flow of blood through the veins in your arm. This makes it easier to put the needle into a vein properly. A small amount of the radioactive tracer is then injected, usually into a vein on the inside of your elbow.
If you are having a multigated acquisition (MUGA) scan, a blood sample may be taken and the tracer added to it, and then it will be reinjected into your vein.
The gamma camera will take pictures as the radioactive tracer moves through your bloodstream and into your heart. It is important not to move while the scan is under way.
The camera does not produce any radiation, so you are not exposed to any additional radiation while the scan is being done. You will need to hold still during each view, which may take up to 5 minutes. You may be asked to:
The radioactive tracer is designed to attach to your blood cells, which takes 20 to 30 minutes. You will then have to wait 2 to 4 hours until the tracer is completely absorbed by your red blood cells. During that time, you may have to stay at the test center. Some test centers may allow you to leave and come back when it is time for your scan.
Testing usually takes 10 minutes to an hour, depending on which studies are done. MUGA scanning may require 2 to 3 hours to obtain all the needed views.
After the test
Once your scan is complete, you usually will be able to leave the testing room right away. You may have to wait at the test center until all of your scan images have been reviewed. If you moved during the scan and the images turned out blurry, the scan may have to be repeated.
Drink lots of water and urinate frequently after your scan to make sure that the tracer flushes completely out of your body. It takes a day or two for the tracer to be completely eliminated.
How It Feels
You may feel nothing at all from the needle puncture when the tracer is injected, or you may feel a brief sting or pinch as the needle goes through the skin. Otherwise, a cardiac blood pool scan is usually painless. You will not feel anything from the operation of the gamma camera. You may find it hard to remain still during the scan. The examination table may feel cool. Ask for a pillow or blanket to make yourself as comfortable as possible before the scan begins.
Allergic reactions to the radioactive tracer are rare. Most of the tracer will be eliminated from your body (through your urine or stool) within a day, so be sure to promptly flush the toilet and thoroughly wash your hands with soap and water. The amount of radiation is so small that it is not a risk for the people you come in contact with after the test.
Occasionally, some soreness or swelling may develop at the injection site. These symptoms can usually be relieved by applying moist, warm compresses to your arm.
There is always a slight risk of damage to cells or tissue from being exposed to any radiation, including the low level of radiation released by the radioactive tracer used for this test.
A cardiac blood pool scan shows how well your heart is pumping blood to the rest of your body.
The most commonly reported value is the ejection fraction, which is the average amount of blood pumped out of the heart's left ventricle during each contraction.
Normal results include:1
Many conditions can affect cardiac blood pool scan results. Your doctor will discuss any significant abnormal results with you in relation to your symptoms and past health.
What Affects the Test
Reasons you may not be able to have the test or why the results may not be helpful include:
What To Think About
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