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About Your Computed Tomography (CT) Exam

Computed Tomography, or CT, is a diagnostic imaging modality that produces a series of cross-sectional images of your body. Recent advances in CT technology have made this type of imaging a valuable tool in the detection of many conditions.

The following prep instructions pertain to all patients having a CT scan. Where noted, special instructions are for patients receiving a contrast agent. A contrast agent is a substance that enhances the images taken during the CT scan.

Before Your CT

When to Arrive

All patients who are having an abdominal or pelvic CT scan should arrive 60 minutes before your scheduled appointment. This is to allow time for you to drink oral contrast (if necessary) and to ensure that the fluid completely coats your digestive tract. The oral contrast helps to highlight body areas for the CT scan. The radiologist will determine if you need oral contrast. For all other CT exams you will need to arrive 30 minutes prior to your scheduled appointment.

Diabetic Patients

All insulin-dependent patients with diabetes who are scheduled for a CT scan should continue to take their insulin as prescribed. Drink extra fruit juices to make up for the two hour period when you will fast from solid foods.

Patients with diabetes should inform their doctor when an oral contrast is going to be part of the CT exam. Tell your doctor that instructions for after the exam were to stop taking medications for 48 hours after the exam.

Food and Drink

For all CT scan patients, you should not eat solid foods for 2 hours prior to your test. You may drink plenty of fluids such as water, broth, clear soups, juice, or black decaf coffee or tea. We encourage you to drink plenty of fluids before your CT exam.

What to Wear

You should dress in comfortable clothing. It might be necessary for you to change into a hospital gown if there is metal in your clothing, such as a zipper, that covers the area of your body that will be examined. If you are wearing jewelry or anything that might interfere with the scan, we will ask you to remove it and store it with your other belongings. It is best that you leave valuable items at home.

Intravenous Contrast Preparation

Many patients receive an intravenous (I/V) contrast agent for their CT exam. If the radiologist has determined that an I/V contrast agent will enhance your CT scan results, the CT technologist will place an I/V in your arm or hand prior to the exam.

During Your CT

You will meet the CT technologist when you are taken into the exam room. The technologist will explain everything that will happen during the scan. You will be helped onto the table and positioned correctly. If you have difficulty staying very still, there is a strap that can help you remain in place. Even slight movement blurs the CT images.

The CT technologist controls the scanner from an adjacent room where they can still see and hear you. You will be moved slightly after each scan, although you may not notice this.

When the CT scan is complete, the technologist will make sure that all of the information the doctor will need has been collected.

Your time in the CT scan room will vary between 10 and 20 minutes for a single exam, depending on the type of exam. Some patients receive multiple exams during the same appointment.

After Your CT

Once all of the required images have been produced, the technologist will help you off the table. You may leave the CT department immediately and resume your normal diet. Drink plenty of fluids for the next two days unless instructed otherwise. Speak with your doctor if you have difficulty moving your bowels following a CT scan that used oral contrast agent.

Some patients experience an adverse reaction to the contrast agent, but this rarely happens. Contact your doctor if you develop a skin rash, difficulty breathing, nausea, or vomiting. If your symptoms are severe, call 911 or go to the nearest emergency room.

The technologist cannot discuss the results of the scan with you. The CT scan will be reviewed by a radiologist and the results will be sent to your doctor, who will discuss them with you.


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