What is CT Scan?
A computerized tomography scan (CT or CAT scan) uses computers and rotating X-ray machines to create cross-sectional images of the body. These images provide more detailed information than normal X-ray images. They can show the soft tissues, blood vessels, and bones in various parts of the body.
Why is CT Scan performed?
The purpose of CT Scan is to diagnose diseases and evaluate injuries. Your doctor may recommend a CT scan to help:
- Diagnose muscle and bone disorders, such as bone tumors and fractures
- Pinpoint the location of a tumor, infection or blood clot
- Guide procedures such as surgery, biopsy and radiation therapy
- Detect and monitor diseases and conditions such as cancer, heart disease, lung nodules and liver masses
- Monitor the effectiveness of certain treatments, such as cancer treatment
- Detect internal injuries and internal bleeding
What should I know before receiving CT Scan?
CT scans may not be a good idea during pregnancy. Tell your doctor if you’re pregnant. Although the radiation from a CT scan is unlikely to injure your baby, your doctor may recommend another type of exam, such as ultrasound or MRI, to avoid exposing your baby to radiation. At the low doses of radiation used in CT imaging, no negative effects have been observed in humans.
Some people may have discomfort from lying on the hard table.
Contrast given through an IV may cause a slight burning feeling, a metallic taste in the mouth, and a warm flushing of the body. These sensations are normal and usually go away within a few seconds.
There are very few risks associated with a CT scan. Though CT scans expose you to more radiation than typical X-rays, the risk of cancer caused by radiation is very small if you only have one scan. Your risk for cancer may increase over time if you have multiple X-rays or CT scans. The risk of cancer is increased in children receiving CT scans, especially to the chest and abdomen.
Some people have an allergic reaction to the contrast material. Most contrast material contains iodine, so if you’ve had an adverse reaction to iodine in the past, make sure to notify your doctor. Your doctor may give you allergy medication or steroids to counteract any potential side effects if you’re allergic to iodine but must be given contrast.
How to prepare for CT Scan?
Certain exams require a special dye, called contrast, to be delivered into your body before the test starts. Contrast helps certain areas show up better on the x-rays.
Let your health care provider know if you have ever had a reaction to contrast. You may need to take medicines before the test in order to avoid another reaction.
Contrast can be given several ways, depending on the type of CT being performed.
- It may be delivered through a vein (IV) in your hand or forearm.
- You might drink the contrast before your scan. When you drink the contrast depends on the type of exam being done. The contrast liquid may taste chalky, although some are flavored. The contrast passes out of your body through your stools.
- Rarely, the contrast may be given into your rectum using an enema.
If contrast is used, you may also be asked not to eat or drink anything for 4 to 6 hours before the test.
Before receiving IV contrast, tell your health care provider if you take the diabetes medication metformin (Glucophage). People taking this medicine may need to stop temporarily. Also let your provider know if you have any problems with your kidneys. The IV contrast can worsen kidney function.
Find out if the CT machine has a weight limit if you weigh more than 135 kilograms. Too much weight can damage the scanner.
You will need to remove jewelry and wear a hospital gown during the study.
What happens during CT Scan?
You can have a CT scan done in a hospital or an outpatient facility. CT scans are painless and, with newer machines, take only a few minutes. The whole procedure typically takes about 30 minutes.
When it comes time to have the CT scan, you’ll be asked to change into a hospital gown and to remove any metal objects. Metal can interfere with the CT scan results. These items include jewelry, glasses, and dentures. Your doctor will then ask you to lie face up on a table that slides into the CT scanner. They’ll leave the exam room and go into the control room where they can see you and hear you. You’ll be able to communicate with them via an intercom.
While the table slowly moves you into the scanner, the X-ray machine will rotate around you. Each rotation produces numerous images of thin slices of your body. You may hear clicking, buzzing, and whirring noises during the scan. The table will move a few millimeters at a time until the exam is finished. The entire procedure may take anywhere from 20 minutes to one hour.
It’s very important to lie still while CT images are being taken because movement can result in blurry pictures. Your doctor may ask you to hold your breath for a short period during the test to prevent your chest from moving up and down. If a young child needs a CT scan, the doctor may recommend a sedative to keep the child from moving.
What happens after CT Scan?
Once the CT scan is over, the images are sent to a radiologist for examination. A radiologist is a doctor who specializes in diagnosing and treating conditions using imaging techniques, such as CT scans and X-rays. Your doctor will follow-up with you to explain the results.
If you have any questions about the CT Scan, please consult with your doctor to better understand your instructions.
Explanation of results
What do my results mean?
CT scan results are considered normal if the radiologist didn’t see any tumors, blood clots, fractures, or other abnormalities in the images. If any abnormalities are detected during the CT scan, you may need further tests or treatments, depending on the type of abnormality found.
Depending on the laboratory and hospital, the normal range for CT Scan may vary. Please discuss with your doctor any questions you may have about your test results.
Hello Health Group does not provide medical advice, diagnosis or treatment.
CT scan. https://www.mayoclinic.org/tests-procedures/ct-scan/about/pac-20393675. Accessed June 15, 2018.
CT (Computed Tomography) Scan. https://www.healthline.com/health/ct-scan. Accessed June 15, 2018.
CT scan. https://medlineplus.gov/ency/article/003330.htm. Accessed June 15, 2018.
Review Date: October 12, 2018 | Last Modified: October 12, 2018