Computed Tomography: How to Prepare for a CT Scan

What Is a CT Scan?

A CT scan is similar to an X-ray in that it can show different views and structures inside your body. Some people may confuse a CT scan and an MRI scan, both are common imaging techniques, but an MRI uses magnetic energy instead of radiation like the cat scan. CT scans are more detailed than an average X-ray—taking anywhere from a couple dozen to hundreds of X-ray images, according to Radiologyinfo.org. These X-rays are layered and computerized to give doctors a 3-D view of your body.

A CT scan allows a radiologist to see things an X-ray can’t show, like certain body structures that overlap or appear clear on an X-ray.

Why It’s a CT Scan Done?

A CT scan is done to get highly detailed images of the inside of the body—commonly used to diagnose and monitor different conditions, including:

• Tumors
• Infections
• Injuries
• Internal bleeding

Additionally, CT scans are useful for guiding medical procedures, such as biopsies and surgeries, and for evaluating the effectiveness of ongoing treatments.

How Do You Prepare Before a CT Scan?

There are very few preparations needed for a CT scan, and your doctor will be able to give you specific instructions if there are any. According to the CDC, women who are pregnant or breastfeeding should inform the medical staff before a CT scan. Additionally, they note that you should fast from food and drink for a few hours before your scan.

If you are scheduled for a CT scan, consider the following steps from the CDC:

• Arrive early so you have time to check in
• You may or may not be asked to change into a hospital gown
• Remove metal objects (such as a belt or jewelry). You should also remove your dentures and eyeglasses, because they may interfere with image results
• Drink only clear liquids (like water, juice, or tea) in the two hours leading up to your appointment (this is especially important for abdominal CT scans)

Contrast Material

Contrast material (also known as contrast dye) is an iodinated contrast substance used in medical imaging to enhance the visibility of internal structures or organs. Barium is another type of contrast that is used for computed tomography (CAT scans). The iodinated contrast material helps to highlight specific areas inside the body — allowing doctors to get a better view. This is particularly useful in identifying tumors, problems with blood vessels, and areas of inflammation or infection, according to the CDC.

CT scanners may require contrast material to improve the visualization of blood vessels, organs, tumors, and other abnormalities that may not be clearly visible with standard imaging techniques.

Contrast dye can be given in a few different ways, according to the CDC, including:

• By drinking a barium solution
• Through an intravenous line (IV) placed in your arm or hand
• By enema (commonly used for abdominal CT scans)

CT Scan Risks

A CT scan does use radiation to gather imaging, so there are some risks involved. According to the CDC, these risks include:

• Radiation exposure, which carries a small risk of potentially harmful effects, particularly with repeated scans.
• Allergic reactions to iodinated contrast or barium, which can range from mild to severe.
• Risk of kidney damage in patients with pre-existing kidney conditions due to the use of contrast material, including barium and iodinated contrast given through intravenous lines.
• Potential for adverse reactions to sedatives, anesthesia, barium, or iodinated contrast used during the procedure.
• Rare risk of developing cancer from the cumulative effects of radiation exposure over time, especially in young children and individuals with high cumulative radiation exposure.

What to Expect During a CT Scan?

CT scans are fairly common, according to Radiologyinfo.org. But if you’ve never had one before, you may be wondering what to expect. Here are some insights from Radiologyinfo.org:

1. ​​Preparation: You may be asked to avoid eating or drinking for a few hours before the scan, especially if iodinated contrast or barium will be used. It's important to follow any specific instructions provided by your healthcare provider.
2. Clothing: You may be required to change into a hospital gown, as clothing with metal components can interfere with the CT scan.
3. Contrast material: If iodinated contrast material is needed for the scan, it may be administered orally, intravenously, or through other routes.
4. Positioning: You will be positioned on a movable table that slides into the CT scanner, which resembles a large, donut-shaped machine. It's important to remain still during the scan to ensure clear images.
5. Monitoring: A technologist will operate the CT scanner from an adjacent room and will be able to communicate with you through an intercom. They will monitor the scan to ensure that the images are high quality.
6. Duration: A CT scan typically takes only a few minutes, but the entire process, including preparation and post-scan observation, may take one to two hours or more, depending on the area that is being scanned.

After a CT Scan

According to the CDC, after your CT scan, you may be able to resume normal activities unless you were given a sedative or anesthesia. If this is the case, you will need some time to recover before leaving and will need someone to drive you home.

Lab Tests Near Me

A CT scan usually needs to be ordered by a physician. If you need a CT scan, you can find a provider who can order one for you using Solv.