CT Scan

Overview

A computerized tomography scan (CT or CAT scan) is a non-invasive medical test that combines special X-ray equipment with computers to produce multiple images of the body’s internal organs and structures. Using the same dose of radiation as that of an ordinary X-ray machine, it produces a picture of an entire "slice" of the body. A computer then takes that data and turns it into three-dimensional images on a screen.

Unlike conventional X-ray exams, CT scans provide very detailed images of many types of tissue, as well as the lungs, bones, and blood vessels, allowing doctors to more easily detect abnormalities.

Please note, CT Scans are offered only in Ontario.

CML HealthCare Clinic, CT Scanner.
Click here to see images from other CML HealthCare locations.

FAQs

How often should the test be performed?

Your doctor will decide when and how frequently this test is required.

Why is this test performed?

Because they provide detailed, cross-sectional views of all types of tissue, CT scans can help your doctor diagnose problems such as cancers, cardiovascular disease, trauma, and musculoskeletal disorders. They can be performed on many areas of the body, including:

• the head and neck, which can reveal injuries, strokes, tumours, infections, bleeding, and blood vessel abnormalities;
• the spine, which may show tumours, fractures, weakened bones, or deformities;
• the chest, which can reveal infection, tumours, and bulges in blood vessels (aneurysms);
• the abdomen and pelvis, which may show infections, injuries, tumours, and inflammatory conditions.

CT scans can also be used to help doctors perform medical procedures or treatments that require a high degree of accuracy, such as biopsies, removal of fluid from organs, and drainage of abscesses.

Are there any risks or precautions?

Although a CT scan is considered to be safe, there is always some risk of side effects or complications due to exposure to radiation.

Although rare, other side effects or complications can include:

• Allergic reaction to the dye used for CT scans. A radiologist or technologist will ask you about your medical history and allergies to determine if you are at risk of having an allergic reaction.
• Kidney damage can be caused by the dye used in CT scans in people with poor kidney function, dehydration, or diabetes. If you have diabetes or kidney problems, talk to your doctor before having a CT scan.

If you are or may be pregnant, inform your doctor and discuss all the risks and benefits of a CT scan. CT scanning, in general, is not recommended because of the risks to the developing fetus.

What happens during the test?

Most CT scans are fast and painless. You will be asked to lie very still on a table that slides through a doughnut-shaped machine. This machine will rotate around the table to take many X-ray images at different angles. The test will take from 5 to 20 minutes, depending on the part of your body being examined.

Some people feel cold lying on the CT table. Others may feel anxious or claustrophobic inside the scanner. If this happens, you might be given a sedative to help you relax.

Sometimes a dye containing iodine is injected into the blood during a CT scan to clarify certain blood vessels and internal organs and make them more visible for the CT pictures. The dye can also be taken by mouth or through a rectal tube.

How should I prepare for this test?

Your doctor may tell you not to eat or drink fluids for four hours before the test. For some CT scans, you may be required to take a laxative or use an enema. If you need to be given a dye, you will be asked to arrive early for your scheduled appointment.

Tell your doctor or pharmacist about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking, and ask whether you need to stop taking any of them before the test. Also inform them about any medication allergies and medical conditions that you may have.

You will be asked to remove all metal objects from your body before having the scan, including jewellery, because metal interferes with the clarity of the X-ray images.

What can I expect after the test?

After the CT scan has been completed, you can return to your normal activities. However, if you took a sedative to help you relax during the scan, you should not drive until its effects wear off. If you cannot wait, get someone to take you home.

Results

The results of your CT scan can be displayed on a computer screen or permanently recorded on film. A radiologist will analyze the images and send a report to your family doctor or specialist, who will discuss the results with you. Your family doctor or specialist may also review your scans. It may take several days to prepare the complete report before it is sent to your doctor. Ask your doctor when your test results should be available.

Click here to download an CT Scan requisition form.

To schedule a CT Scan, please visit our Locations and Scheduling page.