Understanding Brain Perfusion Scans
A brain perfusion scan is a type of brain test that shows the amount of blood in certain areas of your brain. This can help show how your brain is functioning. The areas of the brain that are very active often show greater blood supply, oxygen supply and use of glucose. Tracking these changes can show which areas of your brain are most active. These results may be lower in areas of the brain that are injured or not very active.
Why a Brain Perfusion Scan is Done
You might need a brain perfusion scan if your healthcare provider needs to know how the blood is flowing in your brain. You may need a brain perfusion scan if you have one of these conditions:
- Stroke or transient ischemic attack
- Subarachnoid hemorrhage
- Carotid stenosis
- Cerebral vasculitis
- Brain tumor
- Recent head injury
You also might need a scan if you need surgery on one of the vessels in your brain or neck. The scan will let your healthcare provider look at the flow of blood through your brain.
Types of Brain Perfusion Scans
There are several types of brain perfusion scans. Some tests use radiotracers. These are radioactive substances that send out tiny particles. Tests that use these include SPECT and PET scans. Other tests do not use radiotracers. These include CT perfusion and MRI perfusion.
How a Brain Perfusion Scan is Done
You will lie on the exam table. A healthcare provider will give you the tracer. This is done through the IV (intravenous) line, by mouth, or by breathing in the tracer. It may take an hour or so for the tracer to travel through your body. You will rest quietly during this time. The provider will move you into the scanner for your imaging. You may be told to take a breath and hold it for a short period of time. You may have one or more different scans while you are inside the scanner.
Risks of a Brain Perfusion Scan
All procedures have some risks. Possible risks of the scan include allergic reactions to substances used in the injection or slight pain at the injection site.
Some brain perfusion scans expose you to radiation. These are SPECT, PET and CT scans. MRI scans do not use radiation. In high doses, radiation is dangerous. It increases your lifetime risk for cancer. But it’s important to note that these scans only use a small amount of radiation. Your healthcare provider will only tell you to get a brain perfusion scan if your risks from not getting the test are greater than the risks of the test itself.
Talk with your healthcare provider about the risks that apply most to you. Your risks may vary depending on the type of scan, the reason for your scan, and your overall health.
Having a Brain Perfusion Scan
A brain perfusion scan is a type of brain test that shows the amount of blood in certain areas of your brain. This can help show how your brain is functioning. The areas of the brain that are very active often show greater blood supply, oxygen supply and use of glucose. Tracking these things can show which areas of your brain are most active. These things may be lower in areas of the brain that are injured or not very active.
What to Tell Your Healthcare Provider
Tell your healthcare provider about your medical conditions and all the medicines you take. This includes prescription drugs, over-the-counter medicines, vitamins and other supplements. Also tell your healthcare provider about any changes in your health, such as a recent illness or fever.
Make sure to tell your healthcare provider if you are pregnant or may be pregnant. If so, you may need to delay your test if your scan will use radiation. This is because radiation may pose a risk to your unborn child. Also let your healthcare provider know if you are breastfeeding.
Getting Ready for Your Test
- Follow any directions you are given for taking medicines and for not eating or drinking before the test. You may be told to stay away from caffeine, alcohol, or other drugs known to affect the blood flow in your brain.
- Talk with your healthcare provider if you feel stress when you are in small spaces. Certain types of scanners may cause stress to some people.
- Your healthcare provider may give you more instructions for the type of scan you are having.
On the Day of Your Test
Before your test, you’ll need to remove any metal objects. This includes jewelry, barrettes and eyeglasses.
Each person’s brain perfusion scan can vary. Your healthcare provider can tell you how your scan will be done. In general, you can expect the following:
- You will lie down on the exam table.
- In some cases, a technician or nurse will put an IV into a vein in your hand or arm.
- A healthcare provider will give you the tracer. This is done either through the IV, by mouth, or by inhaling it.
- It may take an hour or so for the tracer to travel through your body. You’ll rest quietly during this time.
- You’ll move into the scanner for your imaging. It’s important that you remain very still during the scanning. You may be told to take a breath and hold it for a short period of time.
- You might have one or more different scans while you are inside the scanner.
After Your Test
You’ll likely be able to go home soon after your scan, unless you are staying in the hospital for ongoing care. If you have an IV line, it will be removed if it’s no longer needed.
You can likely go back to your normal activities right after your scan. Your healthcare provider will let you know if you need to take any special care.
The small amount of tracer in your body will quickly lose its radioactivity. Your body will soon remove it through your urine and stool. Drink plenty of water in the hours after the test. This will help flush out the remaining radioactive tracer in your body.
A radiologist will read and interpret your scan. These results are then sent to your healthcare provider. Ask him or her when you can expect to learn the results of your scan. You and your healthcare provider can use the results to help decide on your treatment plan.
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