Computerized Axial Tomography
CAT scan, CT scan
Computerized axial tomography is an X-ray procedure that generates a series of X-ray images of organs and internal structures, with each picture representing a "slice" of that internal structure. A computer then combines the "slices" to create a 2-dimensional cross-sectional view of structures inside the body. Three-dimensional images can be constructed by stacking two-dimensional images together. Every part of the body can be scanned, including the brain, eyes, chest and abdomen. One of the advantages of the CT scan over traditional radiography is that it enables us to see elements that could not otherwise be seen. That being said, computerized axial tomography highlights health problems that traditional X-rays are unable to detect.
There are several types of scans. The most common one is probably the spiral scan. The patient is placed on a table that moves horizontally while a large tube rotates around the table in a continuous movement.
What is the purpose of this test?
This test is used to confirm a diagnosis, from a pancreatic disease to a brain tumor. Results help the physician determine the best course of treatment.
The examination, which is conducted by a radiologist, takes between 15 and 90 minutes to complete, depending on the area being examined. The patient must remain still throughout the entire procedure. The device does not touch the patient and the patient does not feel anything as the X-ray beams penetrate the body. The patient is alone in the examination room for the duration of the scan. Medical personnel monitor the procedure through a large observation window. As a safety precaution, an intercom is usually at the patient's disposal.
A contrast agent is occasionally administered to highlight certain parts of the body or to outline organs so that areas of interest can be examined with greater ease. Patients are asked to lie on a table. The table passes through a doughnut-shaped device that rotates around the table, while a narrow X-ray beam takes images of the part of the body being examined. A multitude of images are taken from different angles. This device contains the X-ray tubes and the electronic sensors that send the information back to a computer.
The following recommendations are general guidelines. If you have any questions or would like additional information, contact the centre where you will be having the scan.
- Patients generally cannot eat anything for four hours prior to the examination.
- Patients cannot smoke or drink for six hours prior to the exam.
- All jewellery must be removed.
- It is recommended to wear comfortable, loose fitting clothes.
- Depending on the area being examined, you may be asked to remove dentures, hearing aids, glasses and hair clips.
- After the examination, drink plenty of fluids to flush the contrast agent from the body, when necessary.
Certain precautions must be taken prior to the scan. Persons with claustrophobia, anxiety or severe psychiatric disorders may find this particular examination difficult and may therefore be given medication to make the process more bearable. The same applies for very active children. Women who are pregnant should not have scans since X-rays are harmful to the foetus. Persons with iodine allergies must take medication before the scan to prevent reactions, since iodine is often used as a contrasting agent. Although the examination is generally risk-free, X-rays could be harmful over time.
What to know before going for this test
Before going for a blood test, examination or other, it is always a good idea for you to have a complete list of all prescription or over the counter medications and/or natural products you may be taking. If you are unsure or have any questions, your pharmacist will be able provide you with additional information.
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The patient information leaflets are provided by Vigilance Santé Inc. This content is for information purposes only and does not in any manner whatsoever replace the opinion or advice of your health care professional. Always consult a health care professional before making a decision about your medication or treatment.