What is Pediatric CT?
Computed tomography (CT) is an X-ray technique that produces more detailed images of your internal organs than a conventional X-ray can. The CT computer displays detailed picture images of organs, bones and other tissues. This procedure is also called CT scanning, computerized tomography, or computerized axial tomography (CAT).
In children as well as adults CT scanning may be preferred to the customary X-ray exam. It may be performed in newborns and infants as well as older children and adolescents. CT scans may be done with or without contrast materials that are taken by mouth or injected into a vein. These contrast-enhanced exams often depict a particular organ, tissue or blood vessel more clearly.
What are some common uses of the procedure?
A CT scan may be recommended in order to detect a wide range of abnormalities or diseases in any part of your child's body. Some of the common reasons for requesting a CT scan:
- Complications from infections such as pneumonia.
- Birth defects.
- Head injuries.
- Abdominal pain.
- Infectious or inflammatory disorders.
How should my child be prepared for the CAT scan?
If intravenous contrast material is to be used in the exam, the CT staff will need to know whether your child has had a reaction to contrast material in the past; is allergic to iodine or seafood; or has kidney disease. The purpose of asking about allergies is to avoid a possibly serious allergic reaction.
Your child may eat and drink as usual and take needed medication as long as no contrast is to be given and no sedative (calming medication) or anesthesia is planned. If either of these situations applies, you may be advised about dietary restrictions or receive other instructions. With sedation or anesthesia your child probably will not be allowed to eat for three to six hours, depending on age, before scanning.
For a head or neck scan you will have to remove your child's glasses, any removable dental braces or dentures and any jewelry. For a scan of any other part of the body, all metal objects should be removed from the area being examined.
What does the equipment look like?
The CT scanner is a large rectangular unit with a hole in its center, resembling a gigantic doughnut. Your child will lie on a motorized table set on tracks, which can move up or down and slide into and out of the central opening. Both the tube that emits the X-ray beam and the detectors that record radiation passing through the body are built into the scanner and are not visible to the patient.
The computer that processes the CT images is in a remote location. The CT staff will be in a nearby room from which they control the scanner. Your child will be in constant sight via closed-circuit television or through a window into the CT room. Speakers and microphones inside the scanner will permit the technologist to hear and speak to your child as scanning proceeds.
How is the CAT scan performed?
After receiving oral or intravenous contrast material, if needed, and a sedative, if judged necessary, your child will lie down on the scanner couch and be made as comfortable as possible. The head is supported in a cushion using soft straps to maintain alignment. The exact body position depends on what area is being scanned. You should encourage your child to report any discomfort during positioning because it is important to keep very still during the exam.
Once the child is correctly positioned the CT staff will leave the room to begin the scan. For the first scans the couch will move through the scanner to determine its correct starting position for the rest of the scans. The table then will move more slowly as the actual CT scan is performed.
In adults, breath holding is an important way of obtaining high-quality CT images. Most children older than six years are able to hold their breath long enough to complete the scan although they may need coaching and practice. Younger children may be able to hold their breath when asked but are not as reliable as older children and may not be able to hold their breath long enough to complete the scan. Irregular breathing can affect the quality of a CT scan, especially one done to evaluate the chest or upper abdomen. It is often better to have young children breathe quietly and regularly during the scan. The technologist will help to decide about this.
After the study is completed you may be asked to wait for a short time while the radiologist checks the scans to make sure they are clear enough to be easily interpreted. Occasionally it is necessary to have a few pictures repeated.
What will my child experience during the procedure?
With CT scans there are slight buzzing, clicking or whirring sounds coming from the machine during the procedure. Your child will need to lie quietly on his or her back. Foam cushions and Velcro straps are placed on the forehead and arms to prevent movement.
A CT scan may take as little as two seconds or as long as several minutes depending on the information needed. If you are allowed to remain in the room during the scan you must wear a lead-lined garment to avoid exposure to radiation. If you suspect you may be pregnant it would be better for someone else to be with your child.
If contrast material is injected into a vein, your child will feel warm all over but only for a brief time. There will likely be minor pain when the needle is placed into the vein; it is like getting a shot. When the exam is completed and your child, if sedated, is fully awake, you will be free to return home.
General anesthesia may be used in young children who are unable to hold still. In this case you will be permitted to stay until your child has fallen asleep. There may be a somewhat longer wait after the exam to be sure that your child is fully alert.