Computed tomography (CT or CAT scan) is an imaging test that uses X-rays and a computer to make detailed images of the body. A CT scan shows details of the bones, muscles, fat, and organs. CT scans are more detailed than standard X-rays.
In standard X-rays, a beam of energy is aimed at the body part being studied. A plate behind the body part captures the variations of the energy beam after it passes through skin, bone, muscle, and other tissue. While much information can come from a standard X-ray, MRI captures much more detail about internal organs and other structures.
In a CT scan, an X-ray beam moves in a circle around the body. This provides many different views of the same organ or structure. The X-ray information is sent to a computer that interprets the X-ray data and displays it in a two-dimensional (2D) form on a monitor.
CT scans may be done with or without "contrast." Contrast refers to a substance taken by mouth or injected into an intravenous (IV) line that causes the particular organ or tissue under study to show up more clearly on the scan.
CT scans of the brain can give more detailed information about brain tissue and brain structures than standard X-rays of the head. CT scans can give healthcare providers more information related to injuries or diseases of the brain.
A CT scan of the brain may be used to check the brain for tumors or other lesions, injuries, bleeding in the brain, structural anomalies, infections, brain function changes, or other conditions. A CT scan may be done when another type of exam, such as an X-ray, MRI, or physical exam, is not conclusive.
A CT scan of the brain may also be used to see if treatment is working for brain tumors and to look for clots in the brain that may cause a stroke. Another use of brain CT is to guide brain surgery or biopsies of brain tissue. A biopsy is when a small piece of tissue is removed so it can be examined in the lab.
There may be other reasons for your healthcare provider to recommend a CT scan of the brain.
You may want to ask your healthcare provider about the amount of radiation used during the CT procedure and the risks related to your situation. It is a good idea to keep a record of your radiation exposure, such as previous CT scans and other types of X-rays, so that you can inform your healthcare provider. Risks associated with radiation exposure may be related to the cumulative number of X-ray exams and/or treatments over time.
If you are pregnant or think you may be, tell your healthcare provider. Radiation exposure during pregnancy may lead to birth defects. If it’s necessary for you to have a CT of the brain, special precautions will be taken to reduce the radiation exposure to the fetus.
Nursing mothers should talk with the radiologist about when to resume breastfeeding after contrast material is injected.If contrast dye is used, there is a risk for allergic reaction to the dye. Tell your healthcare provider if you are allergic to or sensitive to medicines, contrast, or iodine. Most people will not have a bad reaction from iodine contrast. However, let your healthcare provider know if you have ever had a reaction to any contrast dye, or have kidney problems.
There may be other risks depending on your specific medical condition. Be certain your healthcare provider knows all of your medical conditions.
Make a list of questions and discuss any concerns with your healthcare provider before the procedure. Consider bringing a family member or trusted friend to the appointment to help you remember your questions and concerns and to take notes.
CT scans may be done on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your healthcare provider’s practices.
Generally, a CT scan of the brain follows this process:
While the CT procedure itself causes no pain, having to lie still for the length of the procedure might cause some discomfort or pain, particularly if you’ve recently been injured or had surgery. The technologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain.
If contrast dye was used, you may be monitored for a period for any side effects or reactions to the contrast dye, such as itching, swelling, rash, or difficulty breathing. Tell the radiologist or your healthcare provider right away if you notice any of these symptoms.
If you notice any pain, redness, and/or swelling at the IV site after you go home, tell your healthcare provider as this could be a sign of infection or other type of reaction.
Otherwise, there is no special type of care needed after a CT scan of the brain. You may go back to your usual diet and activities unless your healthcare provider tells you differently.
Your healthcare provider may give you other instructions after the procedure, depending on your particular situation.
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