What to Expect When You Are Scheduled for a CT Scan
What is a CT Scan?
A CT scan, also known as a CAT scan, is short for computerized tomography or computerized axial tomography.
A CT scan uses radiation, sometimes in conjunction with an imaging contrast, to get detailed pictures of the organs inside your body. The radiation that passes through your body is recorded, digitized by the machine, and then sent to a computer that records and displays the information.
Is it dangerous?
While all radiation has some risks, your doctor has decided the small risk is offset by the need to get more information to make a proper diagnosis. I have provided a link below that explains the radiation risks in having a CT scan.
If you are given contrast dye, either orally or by IV injection, there is a small risk of an allergic reaction. Even in the unlikely event you experience a reaction, it will most likely be minor. The most common allergic reactions are nausea and hives.
If you are over 50 or have a medical condition like diabetes and are scheduled to receive intravenous contrast, you will be required to have blood drawn before the exam. This is done to ensure you are healthy enough to receive contrast. There will be a nurse or doctor close by during the exam to check on you, if needed.
Have you ever had a CT exam?
Before the CT scan
IV contrast preparation
As stated above, if your doctor orders an exam requiring IV contrast, you may need to have blood drawn and analyzed. Your doctor's staff will tell you where and when to have this done. The lab or hospital which draws your blood will send the results to the facility doing the CT exam. You will be instructed not to eat on the day of your examination.
Oral contrast preparation
If you are having an abdominal or pelvic examination, you may be required to drink oral contrast prior to the test. Your doctor will tell you when and where to pick up the contrast. When you arrive to get the contrast, you will be given specific directions on when to start fasting and when to drink the contrast.
Note: If you have any difficulty drinking the contrast, be sure to tell the nurse or CT technician before the exam.
What will happen when I arrive?
After you check in, you may be taken to a private area to get changed into a gown. You will be asked to remove any clothing, jewelry, watches, or piercings that may interfere with the scan.
You will be asked more routine medical questions. If you are having a pelvic or abdominal scan using contrast, you will be asked when you last had something to eat, and at what time you drank your contrast.
With an IV contrast injection, you will also be asked about previous allergic reactions. Your blood work results will be double checked if required. A nurse may insert an IV needle at this time, or it may be inserted when you lie down on the table. Some exams for the kidneys will require you to drink a bottle of water after arriving for the exam.
What happens in the exam room?
When you enter the CT room, you will see a table and a large donut-shaped machine. This "donut," called the gantry, is the part of the machine that produces the radiation and records the information produced by it.
The technician will position you on the table. If you need IV contrast, your IV may be placed now and the tubing from the contrast syringes attached. The technician will position you on the table according to what exam is being done. If you are having a scan of the head, you will probably go through the gantry head first. With the chest, abdominal area, or pelvic exams, this is usually done feet first.
After positioning you and explaining what will happen, the technician will leave the room and the scan will start.
What happens during the scan?
The machinery inside the CT gantry will begin to spin and the table will advance through the "donut hole". The speed at which the table moves is dependent on what type of CT scanner the facility has. Don't worry, you won't go too fast!
You will have an initial scan that will show the technician if you are properly positioned on the table. She will also use that initial scan to "tell" the machine exactly where to start and finish the scan. When she is done, she will start the "real" scan.
If the exam requires you to hold your breath, the machine will tell you when to start holding it and it will let you know when you can breathe normally again. If you have hearing problems, let your technician know, so other non-verbal cues can be used.
If you are receiving contrast, when the injection starts you may feel warmth spread through your body, usually starting in your throat. You may feel like you have wet your pants, but that is normal - the feeling only lasts a short time. Some people feel really hot, others feel nothing at all. You may also get a strange, metallic taste in your mouth.
If you feel any pain at all near the IV site, or feel nauseated, tell the technician immediately.
Depending on the exam, you may move in and out of the scanner several times. Some exams are quick, often less than 10 minutes. Others tests may take longer. The technician will explain this before the exam.
Tell the tech or your doctor immediately if you experience any of these symptoms after an IV injection of contrast.
Hives or itching red skin
Difficulty breathing or swallowing
Swelling of the throat
Bluish skin color
What happens when the scan is over?
After the examination, the technician will enter the room and request you sit up. Any IV will be removed, unless you are to have further procedures done that day that require an IV.
If you have had contrast, the technician will tell you to drink plenty of fluids during the day. You will also be told to watch for any unusual symptoms such as hives or swelling. If you have any symptoms or concerns after you leave, please contact your doctor.
Ask any questions you may have, then that's it. You're free to go! The technician cannot tell you what they have seen. Only a doctor is qualified to look at the images and make a diagnosis. When the images are read, your doctor will be notified of the results. This typically takes a few days.
A quick look at the CT scan procedure.
Your friendly CT technician is there to assist you.
The CT technician is there to assist you and to ensure the doctor gets quality diagnostic pictures. The technician will explain what will happen during the exam.
If you do not understand something or are afraid let the technician know! He or she will be glad to help.
If you have questions, do not be afraid to ask. The technician wants you to feel comfortable, informed and relaxed. Remember, the technicians will be able to hear you and speak to you at all times, even after they have left the room.
Addendum: Please remember, every facility has its own procedures, so your scan may not be done exactly as written. Also, I am not a doctor, and I am not qualified to give any medical advice. I am trained as a CT technician and I am on the "other side of the glass."