Computerized (Axial) Tomographic Scan
(CT or CAT Scan)

The CAT scan, also known as CT (Computed Tomography) imaging, is a safe and non-invasive procedure which uses low radiation X-rays to create a computer-generated, three-dimensional image of the brain. It provides detailed information about the structure of the brain by using a series of X-ray beams passing through the head to create cross-sectional images of the brain. These may reveal abnormalities (blood clots, cysts, tumours, scar tissue, etc.) in the skull or brain which may be related to seizures. This allows physicians to examine this structure, section by section, as the test is being conducted. The CAT scan helps point to where a person's seizures originate.

The scanning period is brief, safe and painless.


Before a CAT Scan

• Dress your child in comfortable, loose fitting clothing.
   
• Remove all metal objects such as jewellery, belts, hairpins, hearing aids, glasses, or dentures, as they may degrade the clarity of the images.
   
• Your child should not eat or drink for 4-8 hours before the test if a contrast medium is going to be used.
   
  A contrast medium is a dye which that may be given to you orally or injected into your hand or arm. This fluid goes up to the brain and makes the scan easier to read.
   
  • Some people are allergic to particular contrast mediums. It is important to inform your doctor if your child has any allergies, especially to iodine. You should also inform the doctor if your child has diabetes, asthma, a heart condition, kidney problems, or thyroid condition. These conditions may indicate a higher risk of iodine reactions.
     
  • Following the injection, s/he may feel flushed, have a metallic taste in your mouth, or feel nauseated. Although these are common reactions, it is important for your child to inform the technician of them.
     
  • If your child feels any itching or shortness of breath after the administration of the contrast medium, s/he should inform the technician.
     
  • Another mild reaction which can occur following the administration of iodine is itching over various parts of the body. This lasts from several minutes to several hours and is usually treated with medication.
     
  • More serious but less common reactions may include shortness of breath, swelling of the throat or other parts of the body. These reactions should be treated immediately.
     
  • A CAT scan still provide valuable information without administering a contrast agent. If your child is at risk of reaction to the contrast agent, the physician may decide not to administer it agent during a CAT scan.
     
     

During a CAT Scan

• After the administration of the contrast agent, the technician will assist your child to the scanning table and will position his/her head and body appropriately.
  • Your child's head may be secured with straps to prevent movement, ensuring a clearer CAT scan.
     
• The technician will move to another room from which s/he can still see and hear your child, and will then proceed to move your child into the scanner machine.
   
• A series of X-rays will be taken by a camera which will rotate around your child's head.
   
• It is important that your child lies completely still as the images are acquired.
  • Any movement will blur the image.
  • Your child may be asked to hold his/her breath during the scanning procedure, to help eliminate blurring of the images, caused by the movements of breathing.
     
• During the examination, your child will hear a lot of noise from the machine and the CT table may move slightly. This will not cause any discomfort. The technician will remind your child to keep still and stay calm.
   
• If your child is feeling scared or has any questions throughout the examination, s/he can speak with the technologist via an intercom.
   
• Your child cannot have anyone in the room with him/her during the scanning process. Because the CT scanner uses X-rays, only the person being imaged should be in the CT scanner room during the procedure.
   
• A scan can be obtained in about 15-20 minutes.
   

After a CAT Scan

• Your child can return to all usual daily activities and resume his/her regular diet immediately after the scan, unless instructed otherwise by the doctor.
   
• If your child was given an injection and the injection site remains sore, call your child's physician who can provide the appropriate medication if necessary.
   
• A radiologist will interpret the images and send them to your child's doctor who will review the results with you at a follow-up appointment. Additional tests or a treatment plan will be designed accordingly.
   

Important Considerations

• If your child has allergies or has experienced discomfort because of any contrast agent previously, inform the technologist and the doctor before the examination.
   
• If your child is or may be pregnant, she should not have a CT examination.
   

Personnel

Radiologists
• interpret the CT images and send a report to the referring physician;
• administer or observe the contrast injection.
   
CT technologists
• operate computerized tomography scanner to produce cross sectional views of the body section being scanned;
• perform the examination under the supervision of the radiologist;
• may also administer the contrast injection.
   

Payment

The CAT Scan is covered by the Ontario Health Insurance Plan (OHIP).

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Last Modified: 07/17/2006 11:16:11 AM