What is Computed Tomography (CT)?
Computed tomography (CT) is a special type of x-ray exam that produces detailed pictures of structures inside the body. CT uses a narrow x-ray beam that is directed through the body and recorded by sensitive detectors. This information is analyzed by a computer to produce a cross-section picture or "slice" of the area being studied. Dense tissues, such as bone, appear white on CT images. Less dense tissues, such as brain tissue or muscle, appear in shades of gray. Air-filled spaces, such as in the bowel or lungs, appear black.
During a CT scan, the area being studied is positioned inside a ring or "gantry" that is part of the CT scanner. The ring can tilt and the x-ray scanning devices within it can rotate to obtain the views needed. CT scanning can be used to obtain information about almost any body part.
A dye that contains iodine (contrast material) is often injected into the blood (intravenously) during a CT scan. The dye makes blood vessels and certain structures or organs inside the body more visible on the CT images. If an abdominal CT scan is performed, a contrast material is usually given by mouth (orally).
How do I prepare for my CT scan?
Tell your doctor if you have any allergies, especially to iodine or x-ray contrast, since for some CT exams an iodine dye (or contrast) is given intravenously. If you are allergic, medication will be prescribed for you to take prior to the testing.
If you have a history of kidney problems or diabetes, a blood test (creatinine) will be done before the CT scan to check that your kidneys are functioning properly. The intravenous contrast material used during a CT scan can cause kidney damage in people with poor kidney function.
Tell the technologist if you are on Metformin for diabetes control.
Tell your doctor if you are or suspect you might be pregnant.
You may be asked not to eat or drink for four to six hours prior to your exam.
What can I expect during my CT scan?
A registered technologist will discuss the procedure with you and answer any questions you might have. A radiologist will review your medical history and then tailor the CT study specifically for your medical problems.
For most abdominal exams, you will be given a cup of contrast to drink thirty to sixty minutes prior to the exam. For some exams, intravenous contrast will be injected into a vein in your arm before or during the procedure.
The technologist will position you on the exam table in a donut shaped gantry. At times during the exam the table will move, you may be asked to hold your breath, and you will hear the sound of the x-ray tube circling your body. At all times, the technologist will be able to see you and communicate with you on a two-way intercom. Most procedures take approximately thirty minutes.
The technologist will show your examination to the radiologist, and additional images will be obtained if needed.
What will happen following my CT scan?
After your CT scan, you may resume your normal activities, diet, and medications unless instructed otherwise by the technologist or your doctor. Any contrast given for your exam will be eliminated in a day or two.
Your examination will be reviewed by the radiologist after the exam has been completed. If you choose OnSite Results, your preliminary results will be given to you before you leave our office. Your physician will be sent a detailed final report by fax or mail.