CT Scan of the Head
Your physician has ordered a CT scan of your brain. This computerized analysis provides a three-dimensional view of multiple levels of brain tissue.
You may be given contrast media intravenously during the CT scan. Since contrast media is filtered through your kidneys, you will need to have a blood test to determine kidney function (creatinine level), before you can be given the contrast media. Your doctor will write the order for this test. Be sure you have a kidney function test within 30 days prior to the CT scan.
Scheduling the CT Scan
When you schedule your CT scan, the person scheduling the scan needs to know:
If you have allergies to iodine, any medications, or food (such as shrimp, lobster or other shellfish). If there is a risk of your having an allergic or asthmatic reaction, you may need to take a medication before the scan to prevent a reaction. Discuss this with your doctor.
About any previous reactions you have had to contrast media injections.
What medications you are currently taking.
If you have asthma, kidney problems, and/or a history of cancer.
If you are a female of childbearing age - Inform the scheduler of the date of your last menstrual cycle and whether there is any possibility that you may be pregnant.
If you have diabetes – It is important that your CT scan is scheduled for early in the morning, between 7:30 and 9:00 am, if possible.
Instructions for Diabetics
Insulin: If you are receiving insulin as part of your diabetes regimen, every attempt will be made to schedule your CT scan between 7:30 and 9:00 am. Please consult with your physician regarding the dose of insulin you need to take before the CT scan. Inform your physician that you cannot eat any solid food for 4 hours prior to the scan.
Metformin (Glucophage®): Do not take metformin on the day of your CT scan and do not resume taking it until your doctor has instructed you to do so. Note: Metformin is also present within drugs named Glucovance, Avandamet, Metaglip, Fortamet, and Riomet. After the CT scan, you must have another blood test to check your kidney function before you can start taking metformin again. Call your doctor for the results of the blood test for kidney function and for instructions about resuming metformin. This is to prevent kidney damage and a serious reaction called lactic acidosis.
On the Day of the CT Scan
Do not eat any solid food for 4 hours prior to your CT scan. You may drink clear liquids up until the time of your scan. Clear liquids include water, black coffee or tea, apple juice, clear soda or clear broth.
Take your regular medications at your usual time, except insulin or metformin. (See Instructions for Diabetics on other side).
During the CT Scan
You will lie resting within the CT scanner, with your head immobilized by straps. The machine will rotate around your head, taking x-ray films from multiple planes. You should lie perfectly still and quiet. Please be assured that a technologist is monitoring you at all times. If contrast media is used, it will be injected into your arm through an IV line. At the time of injection, you may have a momentary feeling of warmth and flushing, a salty taste in your mouth, and possibly some mild nausea. This should pass quickly. The scan itself is painless and should take approximately 30 minutes.
After the CT Scan
After the scan, you should be able to resume your normal diet and activities. If contrast media was used, drink at least 5 to 6 glasses of water a day for 2 days after the scan. The water helps flush the contrast from your system. If you must limit your fluid intake because of a heart problem or for any other reason, talk with your doctor about how much water you can safely drink.
If you are a diabetic who takes any medication that contains metformin, you must have a blood test to check your kidney function before you can start taking metformin again. Call your doctor for the results of the blood test and for instructions about resuming metformin. This is to prevent kidney damage and a serious reaction called lactic acidosis.
For Questions, call the Radiology Department where you are having the procedure:
- Thornton Hospital in La Jolla - 858-657-6641
- UC San Diego Medical Center in Hillcrest - 619-543-2280
To Reschedule or Cancel, call 619-543-3405 as soon as possible.
If you call after hours, please leave your name, Medical Record (MR) number, telephone number and a message. Your call will be returned as soon as possible.
Computed Tomography Division
UC San Diego Medical Center
200 West Arbor Drive
San Diego, CA 619-543-6893