Computed tomography (CT)
What is CT scanning ?
It is a cross-sectional examination of the body performed by using x-rays and
a computer. The patient is made to lie on a table which then moves through a small tunnel.
Pictures are then taken with the help of x-ray cameras inside the machine which are then
seen on the computer screen.
How should I prepare myself ?
A plain study of any system does not require any preparation. For an intra venous contrast study to be performed, you should be fasting for atleast 4-6 hours.
What will I experience during the procedure ?
If a plain scan of the head or any other body part has been asked for by the referring specialist, you will be asked to comfortably lie on the table while the computer scans the desired part. In case your doctor has asked for a contrast study, you will be given a substance called contrast medium, either as an intra venous injection, or to drink, or in some cases both. This contrast medium helps to show the organs better and helps in a precise diagnosis. You may be asked to hold your breath while the scanning is performed during a body or chest study.
How long does it take ?
A plain and contrast study of the head would take around 30 minutes, while body scanning would take longer depending upon the part scanned. Nowadays, spiral CT scanners are available which reduce the time of scanning and also provide greater accuracy in certain conditions.
Are there any side effects ?
This study is contraindicated in pregnancy (due to harmful effects of radiation on foetus). There is no other condition in which a CT scan study is contra indicated. In case an intra venous injection is given, it should be well tolerated by you. In the event of an allergy reaction, nausea, itching, a skin rash or similar mild reaction may occur. In rare cases, there could be hypersensitivity reactions. Patients with a history of allergy to drugs, foods, history of allergy to contrast media, bronchial asthma, gout, and thyroid disorders are at a slightly greater risk to developing a contrast reaction. Two types of contrast are available - non-ionic and ionic type contrast; generally the risk is minimum with non-ionic contrast media.