Computerized Tomography (CT)

Dr. Tom St. Amour

Section Chief

What Is A CT Scan?

A CT Scan is a special kind of x-ray that produces pictures of a cross section of a part of the body. “CT” stands for Computerized Tomography. Tomography comes from the Greek word tomos, which means slice or section, and graphia meaning recording.

CT Scanner-with-person

CT Scan Images

  • Detect many conditions regular x-rays cannot
  • Replace exploratory surgery and other diagnostic procedures, saving patient discomfort and inconvenience
  • Used to monitor patient’s progress during and after treatment
  • Distinguish bone, tissue, fat, gas, fluid, etc.
  • Determine if a growth is solid or fluid-filled
  • Determine if an organ’s size and shape are normal

How Do CT Scans Work?

  1. X-ray tube focuses a narrow beam of x-rays across the body
  2. X-ray energy is absorbed differently by different body structures
  3. Receptors detect the number of x-rays remaining after the x-rays have passed through the body
  4. Information is then relayed to a computer and stored there
  5. The x-ray tube rotates around the body, scanning it
  6. Thousands of readings are taken by receptors and recorded in computer
  7. Computer analyzes receptors’ readings at thousands of different points
  8. Information converted into image on video screen

What Does a CT Scanner Look Like?

The CT scanner is typically a large, box-like or circular machine with a short tunnel in the center. You will lie on the examination table that slides in and out of this tunnel. Rotating around you, the x-ray tube and electronic x-ray detectors are located opposite each other in a ring, called a gantry. The computer workstation that processes the imaging information is located in a separate control room, where the Radiological Technologist operates the scanner and monitors your examination in direct visual contact with the ability to hear and talk to you with the use of a speaker and microphone.

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Risks vs Benefits

As with any x-ray procedure, radiation is a risk. However, CT scans are designed to obtain the most information with the least possible radiation exposure.

  • CT scan images give more detailed results than many other diagnostic techniques.
  • CT scans often detect the smallest abnormalities, allowing treatment to begin early, when chances for cure are greater.
  • X-rays used in CT scans should have no immediate side effects.

Preparing For Your CT Scan

Wear comfortable, loose fitting clothing to your appointment. You want to be comfortable while you wait and during the test. You may be asked to change into a gown or scrub pants for your procedure. Since schedules are tight, unexpected delays may happen; bring something to do while you wait.

  1. You should not eat or drink anything for 4 hours prior to your appointment time as intravenous contrast may be used.
  2. You may be requested to have a lab test performed prior to your appointment to check to see how your kidneys are functioning; especially if you are diabetic.
  3. Leave glasses, earrings, jewelry and hairpins at home, or remove before procedure.
  4. Head and Neck Scans: In addition items listed above, you also need to remove all removable metal from your mouth.

Abdomen and Pelvis CT Scan

  • You will usually be asked to drink 1 quart of sugar free Crystal-Lite / contrast to “highlight” your intestines on your scan.
    • The time between when you finish your drink and when you are scanned depends on your symptoms (average wait time is 30 minutes).
    • You may also be asked to drink more as you are being positioned on the table.
  • You may receive Intravenous Contrast. This “highlights” vasculature in area scanned making certain abnormalities easier to see.

NOTE:  If you have had a PREVIOUS REACTION to intravenous contrast (X-ray dye), call and speak with our representative about your reaction prior to coming in. Depending on the reaction, we can call your doctor and have you “pre-medicated” 24 hours prior to your appointment with an antihistamine and steroid.

NOTE:  Breastfeeding mothers – pump and discard your breast milk for 24 hours after having IV contrast, as this could be passed through your breast milk.

Types of Scans

• Head/Brain
• Sinus
• Ears
• Eyes
• Neck
• Chest/Thorax
• Abdomen
• Pelvis
• Spine

What To Expect After The Scan

IV Contrast

  • Your body will excrete IV contrast through your urine
  • Contrast will not discolor your urine or cause you pain
  • Contrast will be gone in 24 hours

NOTE:  Drink plenty of fluids to help your body get rid of the contrast.

Who Interprets My Results & How Do I Receive Them?

The Radiological Physician provides your referring Physician with an interpretation of your CT scan images. Your Physician can then make a diagnosis and explain the findings to you in terms of your health and treatment.

What About Payment?

Radiology Consultants will file all insurance as a courtesy to you. Depending on the Contractual Agreement with your Insurance Company, you may owe a co-payment and/or deductible at the time of service.

*Please bring your Insurance Card with you *

Please visit our BILLING PAGE for specific information on Insurance, Self-Pay, Motor Vehicle Accident, Cash, Debit or Major Credit Card payment options.

Pregnant Patients

Please notify the Radiological Physician and/or Technologist if there is a possibility you are pregnant. Radiation is potentially harmful to a developing baby during pregnancy.

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Source: Radiology Info. org