Computed Tomography (CT) Procedures

About CT

cardiac ctComputed tomography, commonly known as CT or CAT scan, is a painless, non-invasive diagnostic tool that uses a specialized form of X-ray coupled with computer technology to produce cross-sectional images (slices) of soft tissue, organs, bone and blood vessels in any area of your body. CT has revolutionized medical imaging by providing more detailed information than conventional X-rays, making it possible to diagnose and manage certain diseases earlier and more accurately and, ultimately, to provide better care for patients.

Note: (Text in Italics concerns CT scans with contrast)

Uses of CT

CT scans are used to check the size and structure of an organ or other soft tissue and to determine if it is infected, solid or filled with fluid. The scans are used to diagnose tumors, cancers, spinal injuries, heart disease, vascular conditions, brain disorders and various other abnormalities within the body. For example, when someone has abdominal pain, CT can help determine if the cause is acute appendicitis, bowel obstruction or kidney stones.

CT scans also are used to rapidly diagnose traumatic injuries and to guide a number of minimally invasive procedures, such as needle biopsies, catheter placement, fluid drainage and duct and vessel stenting.

How CT Works

CT uses X-rays to detect and record the radiation absorbed by different tissues. During a CT scan, an X-ray tube focuses a precise beam of energy on a section of the body. A computer analyzes the readings from the X-ray at thousands of different points and converts the information into images radiologists and other doctors use to analyze internal organs and tissue.

Our Team

At Emory, we have access to some of the most advanced CT technology available. However, state-of-the-art equipment is only part of the story. While you may only have direct contact with the technologist who performs your exam, it is important to know there is a multidisciplinary team of specialized physicians, medical physicists and scientists responsible for making sure your exam is performed to the highest possible standards. This team interprets your exam results and works closely with your doctor to develop an accurate diagnosis and the most appropriate treatment plan for you.

teaching imageOur radiologists also teach at Emory University School of Medicine and participate in cutting-edge, university-based research. As a result, they are uniquely qualified to provide the best, most up-to-date treatments and techniques with skill and confidence. And because they work within particular specialties - and even subspecialties - their training and exposure to specific diseases and conditions are unmatched in the community. Our faculty members have even been responsible for defining some national benchmarks for CT procedures. This level of skill and training translates into more accurate results and fewer re-exams, saving valuable time and resources for everyone involved.

Safeness of CT Procedures

Although, there is no conclusive evidence that radiation from diagnostic X-rays causes cancer, some studies of large populations exposed to radiation from other sources have demonstrated slight increases in cancer risk. The estimated risk of cancer over a person's lifetime from a single CT scan has been estimated to be a fraction of this risk (0.03%-0.05%).

We are all exposed to small amounts of radiation from environmental sources such as soil, rocks, building materials, air, water and cosmic radiation. The estimated radiation from a single abdominal CT is comparable to the background radiation from environmental sources that you would be exposed to over a 20-month period. For more information about radiation, go to or

For exams requiring contrast dye (produces a clearer image), if you have had an allergic reaction to the contrast dye used in a prior CT study or have kidney disease, please let your doctor or our imaging staff know PRIOR to your CT exam. We can provide medication to prevent this rare event. The risk of a severe allergic reaction from the contrast dye is approximately one in 10,000 people.

If you are or think you may be pregnant, please discuss this with your doctor as pregnant women should undergo CT only if medically necessary. Usually, pregnant women can undergo alternative imaging tests such as sonography or magnetic resonance imaging instead. If you are breastfeeding and receive intravenous contrast dye for your exam, you should discard your milk for up to 24 hours following the exam before breastfeeding again. Please discuss any specific instructions about breastfeeding with your doctor or the imaging center staff. For more information, please visit

Preparing for Your CT Scan

Download CT/MRI Preparation Instructions (PDF)

CT procedures generally are covered by insurance plans, but you or your physician may be required to obtain authorization from or provide documentation of medical necessity to your insurance provider prior to your exam.

You should call Fast Track Admissions prior to your exam date to pre-register. You may call up to 30 days in advance of your exam.

  • For exams scheduled at Emory University Hospital, call 404-686-5270 or 1-800-640-9293.
  • For exams scheduled at Emory University Hospital Midtown, call 404-686-1573
  • Fast Track Admissions also may be required for exams scheduled at The Emory Clinic. Please call 404-778-XRAY or ask your scheduler at the time you make your appointment.

Leading up to your exam:

  • Follow your doctor's instructions regarding any changes in how you take your regular medications and any eating and drinking restrictions.
  • If available, please bring any previous X-ray, CT and MRI (magnetic resonance imaging) results and images with you to the imaging center.
  • Metal objects, such as jewelry and hairpins, may interfere with the CT scan and should be removed prior to the exam or left at home. 
  • We may ask that you not eat or drink for several hours prior to your scheduled exam.
  • For some exams, we may ask you to take a contrast dye orally the night before your procedure.
  • If you are breastfeeding at the time of a procedure that includes the administration of contrast dye, it may be prudent to pre-pump milk for use until the contrast is safely out of your body, usually up to 24 hours.

The actual exam takes only a few minutes, but you should expect to be at the imaging center for one to two hours.

The Day of Your CT Scan

Plan to arrive 30 minutes before your appointment time. If you do not wish to change your clothes for the procedure, please wear a loose workout suit or other loose type of clothing that has absolutely no metal of any kind, including zippers or metal-backed buttons. For women, workout bras are ideal. You will need to remove your bra prior to the exam if it contains any metal.

Once at the imaging center, we will ask you to complete a screening questionnaire regarding:

  • Your medical history
  • Any medications you take
  • Any medication allergies you have
  • Whether you are pregnant, breastfeeding or trying to get pregnant (if you are unsure if you are pregnant, we may either reschedule or ask that you take a urine pregnancy test prior to your exam)
  • Whether you have any metal objects on or in your body

We will ask you to remove any metal-containing items, such as jewelry (including body piercings), hairpins, hearing aids, glasses, wigs with metal clips and some nonpermanent dentures. We will also ask you to remove all objects from your pockets.

The CT Procedure

For Exams without Contrast:

We will ask you to lie still on a table that passes slowly through the "donut" portion of the scanner. Your technologist will leave the room before the imaging begins. The technologist will monitor you during the short scanning process and give any necessary directions, such as holding your breath momentarily, through the intercom. You will also be able to talk to your technologist through the intercom during the exam.

When the exam is complete, we will take you out of the scanner and ask you to remain in the waiting room while we review the images for completeness. Occasionally, additional images are required. 

As we want to compile all of your information before issuing a report, our technologists are instructed not to tell you preliminary results during your study.

For Exams with Contrast:

For some types of scans, before the procedure indicated above, you will be required to receive a contrast dye ahead of time. Screenings with contrast dye are provided as contrast highlights specific areas in your chest and provides a clearer image (NIH). In these cases, you may drink the contrast. For many other CT exams, we will administer contrast into a vein while the CT scan is performed. This intravenous contrast method requires that we place an IV or needle in your arm vein prior to the CT exam; if you have a special venous catheter, we may be able to use it for the contrast. 

If you are given intravenous contrast, you may feel a sensation of warmth or the urge to empty your bladder while it is being administered. This will go away within in a minute or two. It is important to remain as still as possible during this time so that the images we take are not blurry or unclear. There is also a small risk that the contrast dye can extravasate out of the vein it is being injected into and cause some swelling in the arm at the site of the IV. Usually, this event is not serious, with supportive treatment, such as an ice pack, without further care needed.

Following Your CT Scan

Following your exam, you should feel fine and may immediately return to your normal activities unless the technologist or your doctor tells you otherwise.

If you received contrast dye, it is helpful to drink plenty of water to help flush the contrast dye from your body. There is a very small risk of an allergic reaction to the contrast dye. Kidney damage as a result of the contrast dye is rare, but it is more common in patients with diabetes or known kidney problems. Please make sure your technologist and doctor know if you have these or other similar conditions.Call your doctor immediately if any of the following occur:

  • Hives or any other rash
  • Itching
  • Nausea
  • Swollen or itchy eyes
  • Tightness in the throat
  • Trouble breathing

Although rare, these signs and symptoms may indicate a delayed allergic reaction that requires treatment with medication.

It is essential for you to monitor your condition after you leave the center. In this way, you can alert your doctor to any problems right away. 

Your referring doctor will contact you once the results of your CT exam are available and ready for review. Your physician should have your results within four business days.

Scheduling a CT Procedure

For more information, call Emory HealthConnection℠ at 404-778-7777 or 1-800-75-EMORY from 7:30 a.m. to 6 p.m. EST (Monday-Friday).