What Are CT (CAT) Scans?
A computed tomography scan (CT scan), also called computed axial tomography scan (CAT scan), is a type of imaging test. It uses computers and a rotating X-ray machine to take cross-sectional pictures of the body. CT scans give doctors more detailed images than X-rays can provide. Unlike X-rays, they can show organs, soft tissues, and blood vessels in addition to bones.
How Do We Prepare for a CT Scan?
To help ease any fears, talk to your child about how the test is done and why it's needed. You can describe the room and the equipment that will be used, and reassure your child that you'll be close by. For older kids, explain how keeping still helps the scan get good pictures, be done quickly, and not need to be repeated.
Kids won't feel anything during the scan, but explain that they might hear whirring and buzzing sounds as the machine works. The room may feel cool due to air conditioning used to maintain the equipment.
Your child may be asked to remove all clothing and accessories and change into a hospital gown because buttons, zippers, clasps, or jewelry can affect the images.
For some types of CT scans, kids might get a contrast solution, which helps highlight the area being scanned. If so:
- They might get it through an intravenous line (IV) placed in their hand or arm. Placing the IV will feel like a quick pinprick, but the solution is painless as it goes into the vein.
- They might drink an oral contrast fluid before the scan. Some kids don't like the taste, but it can be flavored to make it more appealing.
Infants and young kids might need sedation if they can’t lie still for the scan, which is common. They’ll get these medicines through an IV line.
Kids who will get sedation or a contrast solution might need to not eat or drink anything for a few hours before the scan to make sure that their stomach is empty.
How Is the Test Done?
A radiographer or radiology technologist does the scan. Your child will lie on their back, side, or stomach on a table, which slowly moves into a large, donut-shaped machine. The machine circles the body, taking many pictures from various angles. These pictures are sent to a computer that records them. It can also put them together to form a three-dimensional (3D) image.
The technician will position your child, then step behind a wall or into another room to operate the machine, viewing your child through a window. The technician will speak to your child through an intercom. You might stay in the CT scan room until the test begins, then join the technician in the outer room. Or you might go to a waiting room. If you stay with the technician, you'll wear a lead apron to protect certain parts of your body.
When the procedure begins, the table moves through the CT machine. Older kids will be asked to hold their breath and stay still for a few seconds at a time to prevent blurred images.
Depending on the type of CT scan, the test can take from several minutes to 45 minutes. A child’s actual exposure time to radiation is much less.
After the scan, your child will wait a few minutes as the technician reviews the images. If they're blurred, parts of the CT scan may need to be redone. If your child got sedation, it will take a little while for the medicine to wear off.
Are There Any Risks From CT Scans?
CT scans are painless. A CT scan involves more exposure to radiation than a regular X-ray does, but the risk is small. Radiologists use the minimum amount of radiation needed to get the best results.
If your daughter is pregnant, tell the technician or doctor before the scan to see if another test would be better. There's a small chance that the radiation could harm the developing baby. But if the CT scan is necessary, precautions can protect the baby.
Contrast solutions are generally safe, with a low risk of allergic reactions. They may contain iodine, which might cause problems for kids with an iodine allergy and some other illnesses. Tell your doctor if your child has a medicine, dye, or food allergy. A patient who’s at risk for an allergic reaction to the contrast solution may need medicines like antihistamines or steroids to help prevent a serious reaction.
If your child got sedation, there's a slight chance that the medicines could slow breathing. If there are any problems with the sedation, the CT scan staff is prepared to treat them right away.
When Are Test Results Ready?
The images are checked by a radiologist (a doctor who's trained in reading and interpreting X-ray and CT scan images). They’ll send the results to your doctor, who will go over the results with you.
Results are usually ready in 1–2 days. In an emergency, the results of a CT scan can be available quickly. In most cases, results can't be given to the patient or family at the time of the test.
FAQs
Late adverse reactions after intravascular iodinated contrast medium include symptoms such as nausea, vomiting, headache, itching, skin rash, musculoskeletal pain, and fever.
How long do you feel sick after CT scan with contrast? ›
If contrast dye is used, you may feel some effects when the dye is injected into the IV line. These effects include a warm, flushing sensation, a salty or metallic taste in the mouth, a brief headache, or nausea. These effects usually last only for a few moments.
Can you drive home after a CT scan with contrast? ›
There should be no ill-side effects and you will be able to drive. The only thing we recommend is that you drink plenty of liquids/water after your test is complete (if given contrast). This is so that the contrast dye can be quickly flushed from your body and you do not become dehydrated.
What should I avoid after a CT scan with contrast? ›
If you are given contrast by mouth, you may experience diarrhea after the procedure. Otherwise, there is no special type of care required after a CT scan of the chest. You may resume your usual diet and activities unless your physician advises you differently.
What are the dangers of contrast dye? ›
Allergic-like reactions include nausea, vomiting, hives, bronchospasm, angioedema, and other anaphylactoid responses. Physiologic reactions include cardiac arrhythmias, depressed myocardial contractility, cardiogenic pulmonary edema, and seizures. Preexisting conditions may increase the risk of certain adverse events.
Is CT contrast dye bad for you? ›
In most cases contrast dyes used in tests, such as CT (computerized tomography) and angiograms, have no reported problems. About 2 percent of people receiving dyes can develop CIN. However, the risk for CIN can increase for people with diabetes, a history of heart and blood diseases, and chronic kidney disease (CKD).
Why do I feel weird after CT scan? ›
The CT scan is a very safe procedure. Some people who have an injection of iodinated contrast material may feel nauseous for a short time afterwards. On rare occasions, a person may have an allergic reaction to this substance.
Why no caffeine after CT scan with contrast? ›
Caffeine alters the distribution of the radiopharmaceutical throughout your body, specifically to your heart. Decaf coffee still has trace amounts of caffeine so it is safer to avoid it all together.
Why does CT contrast make me sick? ›
The risks are related to allergic and non-allergic reactions to the injected contrast. Minor reactions to the IV contrast used for CT scan may include nausea, vomiting, headache or dizziness, which are usually of short duration and usually require no treatment.
What's the difference between a CT scan and a CAT scan? ›
A CT scan and a CAT scan are the same thing. CT stands for computerized tomography and CAT stands for computerized axial tomography. The original name for this scan was an EMI scan, named after the company that created the technology.
Some people refer to this as “dye” although it's not like the dye you might use at home. These contrast media are liquid solutions that contain iodine and show up on x-ray. It is removed from the body through the kidneys, but will not change the color of your urine. What does the IV contrast feel like?
What should you not do before a CT scan? ›
For four hours prior to your exam, please do not eat solid foods. You may drink fluids such as water, juice, or black decaffeinated coffee or tea. Some CT scan exams, particularly abdominal CT scans, may require that you drink water or an oral contrast so we may better visualize structures within the abdominal area.
What are the disadvantages of CT contrast? ›
Risks of CT Scan
If contrast dye is used, there is a risk for allergic reaction to the dye. Patients who are allergic to or sensitive to medications, contrast dye, iodine, or shellfish should notify their physician. Patients with kidney failure or other kidney problems should notify their physician.
Is diarrhea common after CT scan with contrast? ›
Possible side effects of an abdominal CT scan
However, if they become more severe, you should call your doctor right away. Side effects of barium contrast can include: abdominal cramping. diarrhea.
How much does a CT scan cost? ›
On average, a CT scan can cost anywhere between $300 and $6,750. Some of the factors that can impact the price of a CT scan include: Part of the body being scanned. Service provider.
How long does it take for CT scan dye to leave the body? ›
The plasma half-life of intravenously administered iodinated contrast medium is approximately two hours, with nearly 100% of the media cleared from the bloodstream within 24 hours.
How long does the dye last in your body after a CT scan? ›
Contrast agents are safe to use during scans, and your body naturally rids you of them within a day or two when you urinate or have a bowel movement.
How long do side effects of CT scan dye last? ›
Delayed adverse reactions to radiographic contrast media are usually cutaneous (reported incidence varies from 1% to 23%) and include rash, skin redness, and skin swelling, sometimes associated with nausea, vomiting, and dizziness, that begin 1 hour or longer (usually 6–12 hours) after the administration of the ...
What are the symptoms of contrast toxicity? ›
The most common symptoms are fatigue, brain fog, skin pain, skin discoloration, bone pain, muscle fasciculations, and pins and needles, but a long list of additional symptoms is reported herein. The time of onset of symptoms ranges from immediate to 1 month after gadolinium-based contrast agent (GBCA) administration.
