Computerized tomography (CT scan) or Computer Axial Tomography (CAT) scan is an imaging procedure that uses an X-ray machine connected to a computer. The scan creates cross-sectional images or slices of the internal structures of the body. Sometimes, a contrast material or dye may also be injected into your arm or any other part of your body for a better view of a particular area. The internal structures are easily visible on the CT scan with the help of the dye.
CT scan images allow the doctor to look at the inside of the body and is usually recommended to help diagnose various conditions including:
- Abdominal and intestinal abnormalities such as tumours, infections, cysts (fluid-filled sac-like structures), and bowel disease.
- Kidney and bladder stones, urinary tract blockage, or other urinary tract diseases.
- Liver diseases and inflammation of the pancreas
- Problems of the pelvic organs
- Injuries to the skeletal structures including the shoulder, elbow, wrist, hand, hip, knee, foot and ankle.
- Enlarged adrenal glands
CT scan is also used to guide procedures such as biopsy, radiation therapy and surgery.
You will be asked to remove any jewellery or metal fastenings that are in the area to be scanned.
The scan may require a contrast dye or substance that improves the picture of certain tissues or blood vessels. This material may be swallowed, given as an enema or injected into the blood stream, depending on the part of your body that is to be scanned.
If you are undergoing an abdominal scan, you will be asked not to eat for six hours before the test.
A CT Scan is usually done by a radiology technologist.
- You will lie on a table that is attached to the CT scanner.
- The table will slide into a large donut-shaped machine which takes images while moving around your body. Each rotation will yield several thin sliced images of your body.
- You may be asked to breathe or hold your breath during the chest and abdomen scanning. You should lie still during the procedure as this increases the clarity of the images.
- The CT scan technologist will watch you through a window during the procedure. You can communicate with the technologist through an intercom.
- You should inform the technologist if you experience any problems during the scan. The entire procedure takes about 30 to 60 minutes.
You can return to your normal routine after the procedure. If a contrast dye was used, you will be instructed to drink plenty of fluids to flush out the dye from the body. In some cases, you may have to wait for an hour to make sure you feel okay after the scan.
Nursing mothers should wait for 24 hours after a scan using a contrast dye before resuming breastfeeding.
Risks and Complications
As with any procedure, a CT scan involves minor risks and complications.
- Doctors do not generally recommend CT Scans without a good medical reason as there is far more X-ray exposure than is involved in ordinary X-rays.
- Pregnant women should not have a CT scan as there is a small risk that X-rays may cause abnormality to the unborn child.
- The contrast dye used in CT Scans often contains iodine, which can cause allergic reaction in some patients.
- Also, the dye may cause some kidney damage to people who already have kidney problems.