What is CT?
CT stands for Computed Tomography (sometimes referred to as a CAT scan). A CT scan produces hundreds of thin slice cross-sectional pictures of the body part being examined, using x-rays and advanced computer processing. It is roughly analogous to looking at a loaf of bread by picking up each slice and looking at it individually. Some examinations require an injection of iodinated contrast material to be given during the scan, while others can be performed without an injection.
Since contrast is excreted by the kidneys, if your kidney function is not good, you should not have IV contrast. We have guidelines when it is safe to use IV contrast, and that is why you may have been asked to have a blood-test before the exam, in order for us to assess your kidney function. Young, non-diabetic patients without a history of kidney disease need not have kidney function checked. If it is anticipated that an exam should be performed with an injection of contrast material, the patient may be given pre-medication to reduce the possibility of a reaction to the contrast material. If you have allergies or may be pregnant, be sure to inform your physician and the technologist prior to the exam. The scanning process itself lasts only 10-30 seconds.
How Is CT Performed?
With the latest multi-detector CT scanners, most examinations take less than 10–15 minutes. Almost all scans can be obtained while simply holding your breath. You will be asked to lie on a comfortable table, which will slide into the opening of the machine, and you will move through the opening as your body is being scanned. If intravenous contrast material is required for your exam, a temporary IV will be placed in your arm by a nurse. For abdominal scans you will be asked to drink a dilute barium solution, beginning approximately two hours before the procedure.