CT Scan

1 What is a CT Scan?

A computerized tomography (CT) scan combines a series of X-ray images that are taken from different angles and uses computer processing to create cross-sectional images, or slices, of the bones, blood vessels and soft tissues inside your body. CT scan image gives more detailed information than plain X-rays do.

A CT scan has many uses, but is particularly well-suited to quickly examine individuals who may have internal injuries from car accidents or any other kind of trauma. A CT scan can be used to visualize almost all parts of the body and is also used to make a diagnosis of a disease or injury as well as to plan medical, surgical or radiation treatment.

2 Reasons for Procedure

Your doctor may recommend a CT scan for the following reasons:

  • To help diagnose muscle and bone disorders such as bone tumors and fractures.
  • To pinpoint the location of a tumor, infection or a blood clot.
  • To guide certain procedures, such as surgery, biopsy, and radiation therapy.
  • To detect and monitor diseases and conditions, such as heart disease, lung nodule, and liver masses.
  • To monitor the effectiveness of certain treatments, such as cancer medication.
  • To detect internal injuries and internal bleeding.

3 Potential Risks

A CT scan is accompanied by various potential risks, including:

  • Radiation exposure: You will be briefly exposed to ionizing radiation during a CT scan. The amount of radiation you will be exposed to is greater than that which you would be exposed to if you would get a plain X-ray because the CT scan gathers more detailed information.
  • CT scans have not been shown to bring about any long-term harm, although there may be a very small potential to increase your risk of cancer. CT scans have many more benefits that outweigh this potential risk.
  • Doctors use the lowest possible doses of radiation to obtain the desired medical information. Also, newer, faster machines and techniques require less radiation than was previously used. Talk with your doctor about the risks and benefits of your CT scan.
  • Harm to babies: It is very important to inform your doctor if you are pregnant. Although the radiation from your CT scan is unlikely to cause harm to your baby, your doctor can recommend another type of testing methods, such as an ultrasound or MRI, to avoid exposing your baby to the radiation.
  • Reactions to contrast material: In some cases, your doctor can recommend you receive a special dye called contrast material through a vein in your arm before your CT scan. Although rare, the contrast material can lead to medical problems or allergic reactions. 
  • Mold reactions are quite mild and result in a rash or itchiness. In rare circumstances, an allergic reaction can be serious, even life-threatening. Tell your doctor if you have ever had a reaction to contrast material.

4 Preparing for your Procedure

In preparing for your CT scan, you must follow your doctor’s orders. 

Depending on which part of your body is being scanned, you may be asked to do the following:

  • Take off some of your clothing and wear a hospital gown.
  • Remove any metallic objects such as jewelry, a belt, dentures, and eyeglasses, which might interfere with the image produced.
  • Refrain from eating or drinking for a couple of hours before your scan.
  • Contrast material: A special dye known as contrast material is needed for some CT scans, this dye helps in the highlighting of the areas of the body being examined.
  • The contrast material blocks X-rays and appears white on images, which could emphasize blood vessels, intestines or other structures.

Contrast material might be given to you in the following ways:

  • By mouth: If your esophagus or stomach is being scanned, you may need to swallow a liquid that contains contrast material. This drink may have an unpleasant taste.
  • By injection: Contrast agents can be injected into a vein located in your arm to help your gallbladder, urinary tract, liver or blood vessels stand out on the images. You may also experience a feeling of warmth during the injection or a metallic taste in your mouth.
  • By enema: A contrast material may be inserted into your rectum to help visualize your intestines. This procedure can make you feel bloated and quite uncomfortable.

5 What to Expect

Read on to learn more about what to expect before, during, and after your CT scan.

You can have a CT scan done in either a hospital or an outpatient facility. CT scan is painless, and with the development of new machines, only take a few minutes to complete. The whole procedure usually last about 30 minutes

During the scan, CT scanners are shaped like a large doughnut standing on its side. You lie on a narrow, motorized table that slides you through the opening into a tunnel. Straps and pillows may also be used to help you stay in position.

During a head scan, the table may be fitted with a special cradle that holds your head still. While the table moves you into the scanner, detectors, and the X-ray tube rotate around you. Each rotation yields several images of thin slices of your body. You may hear buzzing, clicking and whirring noises.

A technologist in a separate room is able to see and hear you. You will be able to communicate with the technologist via intercom. The technologist may ask you to hold your breath at certain intervals to avoid blurry images.

After a CT Scan

After the exam, you can return to your normal activities. If you were given a contrast material, you may receive special instructions. In certain cases, you may be asked to wait for a short period of time before leaving to ensure that you feel well after the exam. After the scan, you will likely be told to drink a lot of fluids to help your kidneys remove the contrast material from your body.

6 Procedure Results

CT images are stored as electronic data files and in most cases viewed on a computer screen. A radiologist interprets these images and proceeds results to send a report to your doctor.

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