The computed tomography scanning (CT Scanning) procedure has advanced rapidly since the 70’s, and has become the imaging exam of choice. Patients should keep in mind that CT scanning does not cause any pain. During a CT scan, a patient is asked to lie very still on a narrow table that slides into the center of the scanner, called the gantry. They may even be asked to hold their breath for a few seconds, to prevent blurring of the pictures. CT scanning takes anywhere from 15 minutes to 1 hour to complete, and the length of the procedure depends on the size of the area being x-rayed. Some patients may be concerned with claustrophobia, but the width of the gantry is wide enough to usually prevent feelings of claustrophobia. Aftercare is generally not required following a CT scan. The technologist will continue to keep an eye on the patient for possible adverse contrast reactions immediately following the exam.
Contrast Agents: Contrast agents, or “dyes”, are often used in CT scanning to demonstrate certain anatomic details that, otherwise, may not be visible. If contrast agents are used in the CT exam, these will be administered (by mouth, injected into a vein, by enema, or given in all three ways) several minutes before the study begins.
The CT Image: CT scanning allows for a more three-dimensional effect. Clear-cut sections of the body can be located and imaged as cross-sectional views, and various densities of tissue can be easily distinguished. Standard findings on a CT exam show bone, the densest tissue, as white areas. Tissues and fluid will show as various shades of gray, and fat will appear dark gray or black. The radiologist can determine if tissues and organs appear normal by the different gradations of the gray scale. Radiologists can also differentiate among types of tumors throughout the body by viewing details of their makeup.
Preparing for the CT Scan
Be sure to remind your patients of these simple steps prior to their scheduled CT scan:
- Wear comfortable, loose-fitting clothing to the exam. (Hospital gowns may be provided during the scan.)
- Metal objects including jewelry, eyeglasses, dentures and hair accessories should be left at home or removed prior to exam. Hearing aids and removable dental work may also need to be removed.
- If contrast material will be used during the exam, patients may be asked to avoid eating or drinking anything four to six hours prior to the scan.
- Be sure to inform the physician of all medications or about any allergies, especially to contrast materials (such as iodine or even shellfish). Bring a list of current medications (prescriptions, over the counter medications, and vitamins.)
- Inform the doctor of any recent illnesses or medical conditions, or history of heart disease, asthma, diabetes, kidney disease, or thyroid problems. Any of these conditions may increase the risk of an unusual adverse effect.
- Women should always inform their physician or technologist if there is any possibility that they are pregnant. Pregnant women or those who could possibly be pregnant should not have a CT scan unless the diagnostic benefits outweigh the risks.
The most common concern with CT Scanning is the radiation exposure. It is true that the radiation exposure from a CT scan can be higher than from a regular x-ray. However, not having the procedure can be more risky than having it. People considering a CT scan must weigh the risks and benefits.
If you have any questions about the CT scanning procedure, or the equipment itself, do not hesitate to call or drop me a line.