Medical Imaging: CT and CAT - What To Expect
Your CT scan appointment with St. Joseph's
Your appointment will take at least 1½ to 2 hours. This includes preparation, 15-30 minutes on the CT scanning table, and post-exam care and/or recovery.
After you register at the registration area, you will be asked to change into a hospital gown. You will be called into the CT suite by the technologist, who will confirm your name, date of birth and the test being done.
During your CT scan, you will be lying on a padded exam table, which will be raised and moved so that the part of your body being examined is inside the CT scanner cylinder. You will be asked to close your eyes as a laser is used to centre your body in the machine. Once your body is correctly positioned you may open your eyes.
The technologist will adjust the machine, if required, explain the steps of the procedure to you, and move to their control station to perform the test. You may be asked to hold your breath during each scan. The table of the CT scanner may gently move back and forth during the exam to obtain images of the entire part of your body being examined.
A CT scan takes only a few minutes. When the exam is complete, the table will be lowered so you can safely transfer to the floor, and you can change into your regular clothes.
Intravenous injection of contrast dye
Some CT exams require an intravenous injection of contrast dye (contrast material containing iodine) that makes blood vessels and other structures inside the body more visible on the CT. If an injection of contrast dye is required for your test, this will be explained to you by the technologist. You will be asked to complete a patient information questionnaire and sign a consent form for the injection before the start of your test. After the test, the contrast dye will be eliminated naturally through your kidneys and bowel.
Your doctor will receive a report approximately 1-2 days following the test and will explain the results to you.
Watch the video below for a demonstration of what happens during CT scan appointment.
Computerized tomography (CT) services
Computerized tomography (CT) services at St. Joseph’s include:
- Scans of the head, neck and face
- Body imaging
- Spine imaging
- Musculoskeletal imaging
- virtual colonography
- Enterography (imaging of the small intestine)
- CT cardio angiogram
For information about safe radiation doses
Before the CT scan
Be sure to tell your doctor if you:
- Are pregnant or think you might be pregnant,
- Have claustrophobia or become very nervous in confined spaces. While it is uncommon, some people may require medication to help them stay relaxed and lie still in the CT cylinder.
- Had an X-ray test using barium contrast material (such as a barium enema) within the past 4 days,
- Have taken a medication that contains bismuth, such as Pepto-Bismol, within 3-4 days before your exam
- Are allergic to the iodine dye used in the contrast material or any other substance that contains iodine. Please call 646-6100 ext. 64652 to discuss this allergy before your appointment.
- Have asthma, are allergic to any medications, or have ever had a serious allergic reaction (anaphylaxis) from any substance, such as the venom from a bee sting or from eating shellfish
- Have diabetes, especially if you take metformin (Glucophage) to control your diabetes
- Have a history of kidney problems or diabetes. Blood work may be required before your CT scan to check that your kidneys are functioning properly as the contrast dye used for a CT scan could cause kidney damage in people with poor kidney function.
What will happen at my appointment?
Please arrive and register at the Diagnostic Imaging Centre at your scheduled arrival time. After you register, you will change into a hospital gown and the nurse will give you instructions to prepare for your scan.
- An IV line will be started in a large vein in your arm to administer the contrast dye during your procedure.
- The nurse or technologist will clean three small areas on your chest and place small, sticky electrode patches on these areas to measure your heart’s electrical activity during the test using an electrocardiograph (ECG) monitor. Male patients should expect to have their chest partially shaved to help the electrodes stick.
- The nurse or technologist will also take your blood pressure and heart rate to determine if medication is needed to bring down your heart rate for the test.
- During your CT scan, you will be lying on a padded exam table. The table will be raised and moved so that the part of your body being examined is inside the CT scanner cylinder. You will be asked to close your eyes and place your arms on a pillow above your head as a laser is used to centre your body in the machine. Once your body is correctly positioned, you may open your eyes. The technologist will adjust the machine, if required, explain the steps of the procedure to you, and move to their control station to perform the test.
- The table of the CT scanner will move into the scanner and you will receive the contrast dye through your IV. It is common to feel a warm to hot sensation as the contrast circulates through your body.
- During the scan, which will take approximately 15 minutes, you will be asked to lie still, without moving. You will also be asked to hold your breath multiple times for about 15 seconds. Try practicing holding your breath before your appointment and let the technologist know if you think this may be a problem.
- When the exam is complete, the electrodes and IV will be removed, the table will be lowered so you can safely transfer to the floor, and you can change to your regular clothes.
- You will be asked to remain in the medical imaging area for 15 minutes to 1 hour after your scan, depending on the medications you received.
- After the procedure, you may resume normal activities and eat as usual. If you received medication to slow down your heart rate, you may feel dizzy, drowsy, or notice a headache. You will need a driver to take you home.