Computer Tomography (CT)

CT scans are much more detailed than regular X-Rays and can identify many conditions that can escape detection on other imaging tests.

A CT Scan, “Computerized Tomogram” or CAT scan is a non-invasive medical test that helps physicians diagnose and treat medical conditions, that may not be visible on other types of medical studies by using advanced x-ray technology to take pictures of your body.

  • A CT scanner is a doughnut shaped machine (known as the gantry) that uses advanced x-ray technology to take pictures of your body.
  • Immediately after it scans your body, a computer in the scanner reconstructs the data into cross-sectional pictures of your body, called slices or sections.
  • CT technology allows radiologists the ability to see more than what a regular x-ray would provide.  
  • Advanced scanner technology provides images of exceptional quality and lowest possible radiation dose. Lower dose means increased safety for you.
  • Higher quality images mean more information for the radiologist to diagnose.   
  • Following diagnosis a plan can be determined for treatment for your medical condition.

  • The patient lies still on a table that can move up or down, and slide into and out from the center of the ring.
  • Within the machine, an x-ray tube on a rotating gantry moves around the patient’s body to produce the images, making clicking and whirring noises as the arm moves.
  • The technologist will be able to see and speak to the patient, the patient will be alone in the room during the exam.
  • Immediately after it scans the patient, a computer in the scanner reconstructs the data into cross-sectional pictures of the body, called slices or sections.
  • CT technology allows radiologists the ability to see more than what a regular x-ray would provide.  
  • Advanced scanner technology provides images of exceptional quality and lowest possible radiation dose.
  • CT scanning works very much like other x-ray examinations.
  • Very small, controlled amounts of x-ray radiation are passed through the body, while different tissues absorb the radiation at different rates.
  • With plain x-rays, when special film is exposed to the absorbed x-rays, an image of the inside of the body is captured. With CT, the film is replaced by an array of detectors, which measure the x-ray profile.
  • Inside the CT scanner is a rotating gantry that has an x-ray tube mounted on one side and an arc-shaped detector mounted on the opposite side.
  • During each full rotation, as the fan-shaped x-ray beam is emitted through the patient’s body, an image of a thin section is acquired.
  • The detector records about 1,000 images-or profiles-of the expanded x-ray beam with each rotation.
  • The profiles are then reconstructed by a dedicated computer into two-dimensional images of the sections that were scanned.
  • Multiple computers are typically used to control the entire CT system.
  • You might think of it as looking into a loaf of bread by cutting the bread into thin slices.
  • When the image slices are reassembled by computer, the result is a very detailed, multidimensional view of the body’s interior.
  • You may be asked not to eat or drink anything for several hours beforehand, especially if a contrast material is going to be used in your exam.
  • You should inform your physician of any medications you are taking and if you have any allergies. If you have a known allergy to contrast material, your doctor may prescribe medications to reduce the risk of an allergic reaction.
  • Inform your doctor of any recent illnesses or other medical conditions, such as a history of heart disease, asthma, diabetes, kidney disease, or thyroid problems.
  • Any of these conditions may increase the risk of an unusual adverse effect.
  • If you think you may be allergic to IV contrast material or have experienced a prior reaction to IV contrast material, please notify your referring physician prior to scheduling your CT scan appointment.
  • If you have a known allergy to contrast material, your doctor may prescribe medications to reduce the risk of an allergic reaction.
  • You should wear comfortable, loose-fitting clothing to your exam.
  • Certain exams may require you to wear a gown, which will be provided.
  • Metal objects including jewelry, eyeglasses, dentures, and hairpins may affect the CT images and should be left at home or removed prior to your exam.
  • You may also be asked to remove hearing aids and removable dental work.
  • That shouldn’t be a problem. A CT Scanner is an open machine not a tunnel like an MRI scanner.
  • You are not enclosed in the scanner and, as a result, you see completely around yourself.
  • Some abdominal CT scans require the administration of water or oral contrast material to allow the radiologist to evaluate your bowel and also to separate bowel from other important structures.
  • Oral contrast materials may be made with barium or iodine.  Barium-based contrast material is a thick white flavored drink similar to a milk shake. Iodine-based contrast material is a concentrate mixed with water or juice.
  • For optimal imaging, approximately one liter of oral contrast material should be consumed during the hour prior to your scan. If you are having a CT scan of your abdomen or pelvis, you will need to arrive 1 hour before your appointment.
  • In some medical conditions and types of study, you may be asked to drink one bottle of barium sulfate at bedtime the night before the study.
  • Women should always inform their physician and the CT technologist if there is any possibility that they are pregnant.
  • Your physician and the radiologist will determine if IV contrast material will be needed for your CT scan.
  • IV contrast material containing iodine is used to highlight organs and blood vessels that are otherwise difficult to visualize.
  • If IV contrast material is required for your CT scan, a small IV will be placed in your arm or hand prior to the CT scan.
  • A CT Technologist will take you into the CT Scanner room. Here, you will be positioned on the table which will move into the gantry or doughnut of the CT Scanner.  
  • At this point, the CT technologist will exit the room.
  • Through an intercom system, you and the technologist will always be able to speak with one another.
  • Once your scan is completed, you may resume your regular diet and activities.
  • We recommend that you drink plenty of non-alcoholic, decaffeinated fluids, such as water or juice, to help your body flush out any IV or oral contrast material.
  • After your CT scan, a subspecialized radiologist will read the images and dictate a report that will be sent to your doctor, who will contact you with the results.