CAT Scan FAQs

1. What is a CAT scan or CT scan?

A CAT Scan or CT Scan is a computerized axial tomography scan that is an x-ray procedure combining many x-ray images with the aid of a computer to generate cross-sectional views and, if needed, three-dimensional images of the internal organs and structures of the body. Computerized axial tomography is more commonly known by its abbreviated names, CT scan or CAT scan. A CT scan is used to define normal and abnormal structures in the body and/or assist in procedures by helping to accurately guide the placement of instruments or treatments.

A large donut-shaped x-ray machine takes x-ray images at many different angles around the body. These images are processed by a computer to produce cross-sectional pictures of the body. In each of these pictures the body is seen as an x-ray “slice” of the body, which is recorded on a film. This recorded image is called a tomogram. “Computerized Axial Tomography” refers to the recorded tomogram “sections” at different levels of the body.

Imagine the body as a loaf of bread and you are looking at one end of the loaf. As you remove each slice of bread, you can see the entire surface of that slice from the crust to the center. The body is seen on CT scan slices in a similar fashion from the skin to the central part of the body being examined. When these levels are further “added” together, a three-dimensional picture of an organ or abnormal body structure can be obtained.

2. What will my child (or adult) experience when he/she has a CT scan?

CT exams are generally painless, fast and easy. With helical CT, the amount of time that the patient needs to lie still is reduced.

Though the scanning itself causes no pain, your child may experience some discomfort from having to remain still for several minutes.

If an intravenous contrast material is used, your child will feel a slight pin prick when the IV is inserted, usually into the hand or arm. The child may have a warm, flushed sensation during the injection of the contrast materials and a metallic taste in his/her mouth that lasts for a few minutes. Occasionally, a patient will develop itching and hives, which can be relieved with medication, if necessary. If your child becomes light-headed or experiences difficulty breathing, you should notify the technologist or nurse, as it may indicate a more severe allergic reaction. If your child experiences any kind of reaction to the intravenous contrast, it is important that you and/or your child remember to tell health care providers in the future.

If the contrast material is swallowed, your child may find the taste mildly unpleasant even if mixed with soda or juice; however, most patients can easily tolerate the oral contrast. Your child can expect to experience a sense of abdominal fullness and an increasing need to expel the liquid in the rare situation where the contrast material is given by enema. In this case, encourage your child to be patient, as the mild discomfort will not last long.

When your child enters the scanner, special lights may be used to ensure that he/she is properly positioned. With modern CT scanners, your child will hear only slight buzzing, clicking and whirring sounds as the CT scanner revolves around him/her during the imaging process.

The technologist will leave the room to perform the CT scan. However, the technologist will be able to see, hear and speak with your child at all times. A parent may be allowed in the room but will be required to wear a lead apron to prevent radiation exposure. The radiation dose directly outside of the CT scanner itself is very low. If you suspect you may be pregnant, however, it would be better for someone else to be with your child.

Some imaging facilities may use general anesthesia or conscious sedation in young children who are unable to hold still. In this case you may be permitted to stay in the exam room until your child has fallen asleep. There may be a somewhat longer wait after the exam to be sure that your child is reasonably alert.

Generally, after a CT exam, your child can return to his/her normal activities. If your child received some form of sedation for the exam, you and your child will stay in the department for a recovery period and will be given instructions on any limitations in activity for the day. (Quoted material above was sourced from www.radiologyinfo.org.

3. Why do you need to have a CT scan of your ear?

If you are trying to find out if you are a candidate for canalplasty (atresia repair), only a CAT Scan or CT Scan can reveal the best detailed image of the bony structures within the inner ear. In order for a canalplasty surgeon or an ENT to verify that you are a candidate, he/she must be able to see if the inner ear bones are in tact, where and how they are positioned, if any of them are malformed, and what is missing. All of these details are very important for the surgeon to know in order to make the decision for surgery on a patient. Only a CT Scan can capture enough detail in its image in order to see what exists of the boney structures.

4. How old should my child be before having a CT scan taken?

It is suggested by many medical professionals to wait as long as you possibly can before subjecting a child to a CT Scan. Sometimes, if a child has cranial issues, deformities, or is non-responsive at birth, a medical professional may request a CT Scan of your child immediately following birth in order to rule out any related syndromes, disorders, or various issues of concern or risk. Only in these cases should a CT scan be given to a child. It is possible to ask your child’s doctor if the CT scan can wait a bit longer and if it is absolutely necessary right this minuted. Try and wait to have a CT scan closer to planning for surgery, if a CT scan is required for the surgery you are considering having.

5. How much risk do CAT scans present?

CT scans should not be abused (over used) and definitely should not be used to just take a look inside of something (head and ear cavities) just to see what is going on. For example, “around 62 million scans [today in the US] are performed per year, [when] compared with only 3 million in 1980. Moreover, the researchers estimate that a third of those CT scans are entirely unnecessary—many of them now performed by cautious doctors on worried people with no symptoms at all.” A CT scan should only be taken if the family is beginning to plan for that child’s surgery. The same risk applies to adults, but the risk is not as severe in an adult as it is in a child. For example, just imagine a CT scan being taken of a child who weighs only 8 lbs being given the same amount of radiation exposure that an adult who weighs 175 lbs receives when having a CT taken. “For children, the risk of developing a fatal cancer is somewhere around 1 in 500 or 1 in 1,000—the older you get, the lower the risk becomes. So if someone is 90, for instance, there is virtually no cancer risk. For an adult, the risk is around 1 in 2,000.”Just be cautious. As a parent, you can protect your child and as an adult you can protect yourself. Only have a CT scan when absolutely necessary and do not have multiples taken, especially within the same year when there are no serious issues that require the CT scans in the first place. (Quoted material above was sourced from the article: “Doctor Says Get a CT Scan. Should You?” By, Matthew Shulman, November 28, 2007, US News).

6. Are there any “safer” CT scans today?

It depends. To compare how much radiation is emitted from a regular x-ray and from a CT scan, say for example, the chest area, “… a typical chest CT means around a 175-times-greater dose of radiation than a similar chest X-ray—that’s like 20 sets of mammograms. That range can be between 20 and 200 times higher depending on which part of the body is being scanned [and how young the patient is, weight wise].” However, technology is changing and there are now options for CT scans that emit a little less radiation than other CT scans. For example, there are CT scans that now emit different amounts of radiation based on weight. Some children’s hospitals have these CT scans so that an 8 lb child does not receive the same amount of radiation as a 175 lb adult. You can ask your doctor for help locating a CT scan that is adjustable to weight.

There is also another CT scan that is smaller called the MiniCAT scan. The MiniCAT is a miniature CAT scan made by a company called Xoran Technologies, Inc. designed for high resolution but lower or minimal radiation exposure for younger children. This CAT scan is accepted by most surgeons (maybe not all) and may be available in some of their offices. It is very important to note that when planning for canalplasty surgery, the MiniCAT scan is not accepted by all doctors and or surgeons because there just may not be enough detail that the surgeon is looking for. In this case, if you had the MiniCAT scan used on your child and then you find out that the surgeon was unable to clearly read it due to lack of detail, you now would have to subject your child to another CT scan with the use of a regular CT scan unit. Your child now has received two scans, still exposing him/her to radiation exposure. It is strongly advised to ask your surgeon which type of CT scan he/she would like of your child. Often times, the surgeon him/herself will order the CT themselves to avoid any complications. If you are interested in finding a location near you for a Mini-CT you can call Xoran’s toll Free Number at (800) 709-6726 or visit their website at http://www.xorantech.com. I am sure their customer service hot line can also explain the differences of a Mini-CT vs. a typical CT scanning device. (Quoted material above was sourced from the article: “Doctor Says Get a CT Scan. Should You?” By, Matthew Shulman, November 28, 2007, US News).