What is a head CT scan?
A head CT scan is a special x-ray that provides information about the brain. It uses computed tomography (CT) technology--also called computed axial tomography (CAT)--to provide multiple views of the blood vessels, brain tissue, and skull. The CT scan involves the use of ionizing radiation to provide these images. The radiation dose you are given is higher than what you would receive from a regular x-ray, but it also provides more information to your doctor than a regular x-ray.
When you have the head CT scan, you will be positioned on a narrow moving table that slides through an open doughnut-shaped machine that generates the images. This is not an enclosed tunnel. You may hear whirring noises during the test while it takes the images.
In some cases, you will not need to have an IV (intravenous) line inserted. This is called a head CT without contrast. However, if you are scheduled for a head CT with contrast, you will have an IV line inserted by a health care worker who will inject iodine into the IV. Iodine helps highlight the blood vessels and other structures within the brain and gives more detailed images of the brain structures. This chemical is removed naturally after the exam by the kidneys.
Why is a head CT scan done?
A head CT scan is performed to further evaluate the skull and brain tissue. It is a very useful and commonly performed test. It can provide information about fractures of the skull, bleeding into the brain, and brain cancers. It can also show various diseases of the brain tissue, including strokes and infections, as well as age-related changes.
How long does a brain CT take?
On average, a head CT takes about 15-30 minutes to perform. There are some preparations that will need to be done, including paperwork about your medical conditions and changing into a gown. You will also have an IV line inserted if you are having a head CT with contrast performed. These preparations will take additional time.
Is a head CT scan serious?
A head CT scan is a very commonly performed imaging test that is only a little more involved than a regular x-ray. It does not involve any type of surgery. You will usually be able to drive home on your own right after the test is completed.
If you are pregnant or diabetic, you should inform the CT scan technician or scheduler ahead of the exam to assess if you are a good candidate for this test.
What are the side effects of a CT scan?
Most people have no side effects from a head CT scan. If you receive a head CT with contrast, there is a small risk of having an allergic reaction to the injected iodine. If you have a history of an iodine allergy, or have a sensitivity to shellfish, you should notify the CT technician ahead of time, when scheduling the test. In these cases, steroids and other medications may be given to you in advance of the iodine injection, which helps prevent an allergic reaction.
When you receive the iodine injection, you may feel a warm or flushed sensation. You also may have a metallic taste in your mouth. Both of these feelings are expected and resolve quickly.
The risk of cancer from the radiation dose you receive from a single CT scan is very low. The information that is generated by the test and the benefit to your overall health that the CT scan provides will usually offset the minimal increase in overall cancer risk. The risk of causing cancer is higher in patients who receive multiple CT scans over a long period of time.
Which is better MRI or CT scan for brain?
Both the MRI and CT scan of the head are commonly performed and important tests for diagnosing brain problems. The decision on whether you should have a brain MRI or CT scan is made by your physician, depending on your symptoms and what your medical history involves.
The brain MRI differs from the CT scan in that the MRI involves use of a magnetic field and radio waves that produce various images of the brain and surrounding structures. This test involves being positioned in an enclosed tunnel to generate the images.
An MRI of the brain helps detect brain aneurysms, brain tumors, areas of stroke, and multiple sclerosis, among other conditions.
