A CT or CAT (Computerised Axial Tomography) scan is a special type of x-ray that takes pictures of different cross-sections of a body part by moving the x-ray machine around the patient. Ordinary x-rays, like chest x-rays, give two-dimensional pictures while the CT scan obtains very detailed three-dimensional pictures.
Inpatients are taken to the CT scan department in a wheelchair or on a stretcher. Outpatients can simply go to the CT scan department at their scheduled appointment time.
Contrast media (dye) may be used, depending on the test needed. A dye is a chemical substance through which x-rays cannot pass and it can outline certain body structures. Although it is called a dye, it will not change the colour of the body. If intravenous contrast is required, it cannot be given through the Hickman line, so an IV will be started in the hand or arm, and removed once the test is finished. If an IV dye is used, you will be asked if you have any allergies, as some dyes may cause a reaction. However, reactions are not common.
The IV contrast dye may cause a warm, flushing feeling and may also give a salty taste in the mouth. If an abdominal CT scan is being done, an oral contrast agent, gastrograffin, will need to be swallowed the night before and on the morning of the CT scan.
The CT scan procedure is not painful, but you must lie very still for up to 15-20 minutes at a time. The procedure may seem frightening because of the size of the machine and because you are alone in the room for several minutes at a time. There is a technician in the next room the whole time, watching to see how you are doing. A nurse usually waits in the department and the nurse and technician can communicate with you via an intercom.
A CT scan takes about 1 ½ to 2 hours to complete.
If your white blood cell count is low, you will be asked to wear a mask while out of your hospital room.