Alternatives to CT
Medical imaging has changed the practice of medicine, and many diagnoses are made or confirmed on the basis of imaging tests. Computed tomography (CT) is a valuable and readily available way to diagnose a variety of conditions, which explains its popularity and increased use over the last 20 years. Recent evidence indicates that CT performed in children carries a small but real increased risk of cancer later in life, and that this risk is larger for younger patients. This does not mean that CT should never be performed; it is often the best test in many situations and can provide valuable and even life-saving information. However, in many cases there are other ways to obtain the same medical diagnostic information without exposing a child to radiation by using ultrasound (US) or magnetic resonance imaging (MRI).
- Ultrasound is particularly valuable in children, since their smaller size and lesser body fat allows for high quality and high resolution imaging. Instead of passing x-rays through the body, US uses pulses of sound to create images. Images are obtained by placing an US transducer (also called a probe) on the child using a special gel that allows the sound waves to get through the skin. US can image almost any area of the body; the only limitations are that US cannot “see” through bone or air. US can also provide information about blood flow, and thus can help evaluate the function of organs as well as their anatomy. A criticism of US is that it is very dependent upon the skill and care of the person performing the examination. Questions you can ask your imaging provider include whether or not the sonographers performing the examination are credentialed, is the ultrasound department credentialed, and whether or not the interpreting physicians have special training and education in ultrasound.
- Magnetic resonance imaging creates images of the body by using magnets and radio waves, and does not expose patients to radiation. The main disadvantage of MRI in children is the need for the patient to be very still, as even small amounts of motion will ruin the image. This means that younger children often need sedation, which requires specialized equipment and staff training not available from all imaging providers. Newer and faster MRI techniques are helping to lessen problems from patient motion, and coaching and distraction techniques can help even very young children successfully complete an MRI exam. Again, questions to ask your imaging provider include whether or not the technologists are registered, is the facility accredited for MRI, and are the physicians involved specifically trained in sedating and imaging children.
US and MRI are non-radiation methods of imaging that provide important diagnostic medical information. Depending upon the clinical situation, CT may still be the best and most reasonable study. Properly performed, the potential risks of CT can be minimized, and the small potential risk worth the information obtained. In some situations, US or MRI may be equally viable imaging options, without imposing the even small risk of problems later in life. If you think that US or MRI might be an option for your child, you should ask your child’s clinical or imaging physician. Information about CT is available on this website. Other resources that you may find useful are:
- Information on accredited US and MRI facilities by the American College of Radiology can be found at: http://www.acr.org/MainMenuCategories/PatientInfo.aspx
- Information on accredited US facilities by the American Institute for Ultrasound in Medicine can be found at: http://www.aium.org/accreditation/intro.asp
- Information about US examinations can be found from the Society of Radiologists in Ultrasound (http://www.sru.org/services2.asp), and from the America Institute for Ultrasound in Medicine (http://www.aium.org/patient/aboutExam/abdomen.asp).