The use of computed tomography or CT scans is decreasing, whereas the use of alternate diagnostic imaging methods is increasing in hospitalized children, found a study published this month in Pediatrics.

It appears medical providers are opting for other methods due to concerns over ionizing radiation, which may affect lifetime cancer risks for pediatric patients.

Researchers looked over 150,000 hospitalizations from 33 pediatric centers who submitted data from 2004-2012 to the Pediatric Health Information System. They examined trends among the 10 diagnosis codes associated with the highest CT use during admission in 2004, including CT, ultrasound or US, and MRI. Five of the diagnosis codes were neurological and three were abdominal in nature.

The decrease in imaging utilization was most noted for patients with a diagnosis of seizure where CT utilization decreased by almost 50 percent, and MRI utilization decreased by more than 10 percent. US use increased for all diagnoses codes besides the neurological ones, with the greatest increase noted in appendectomy and gastroenteritis. The study's authors could not draw conclusions on whether shifts in imaging may affect the quality of care based on the results of their study.

What's the background behind this shift? In the past two decades, previous studies investigating the frequency of CT scan use in children documented a large increase from the mid-90's. Since 2001, other studies have led to increased awareness of the potential risks of exposure to ionizing radiation to children. Children's exposure to ionizing radiation from the usual doses used in CT scans has been associated with one additional cancer per 10,000 exposed children.

Due to this concern, the Society for Pediatric Radiology led the formation of the Alliance for Radiation Safety in Pediatric Imaging in 2006. (See my related blog, How much radiation is too much for my child?)  The alliance's initial focus was to decrease radiation doses when imaging children. Around the same time, several investigations identified situations in which CT imaging was not helpful in the management of children, such as those with very low risk of brain injury, new-onset seizures, or with low risk for appendicitis based on clinical scoring. A clinical score is a numerical score based on the presence of a combination of specific findings on a patient's history, physical examination, or laboratory results,
which statistically identifies the patient's likelihood of having appendicitis.

The effects of the decrease in use of CT on clinical outcomes of appendicitis was reported by another group of investigators in a study from JAMA Pediatrics last month. Appendicitis remains the most common surgical emergency in children. The investigators looked at trends in use of US and CT for children with appendicitis, and studied simultaneous changes in important clinical outcomes such as changes in the proportion of negative appendectomy (finding a normal appendix at surgery), perforated ("burst" or ruptured) appendicitis, and Emergency Department revisits.

Although appendicitis is more accurately diagnosed by CT, US rapidly became the imaging modality of choice when the medical community and the public became aware of the hazards of medical radiation exposure. US, however, has limitations -- it is highly dependent on the technical skill of the ultrasonographer. It can also be challenging in overweight patients, or patients who have significant abdominal pain. With these known disadvantages of US, the investigators expected negative outcomes with increased frequency of negative appendectomies, appendiceal perforations, or cases of missed appendicitis as measured by ED revisits.

The researchers reviewed the PHIS database for children who presented to the ED with the diagnosis of appendicitis or who underwent surgery for appendicitis (appendectomy) in 35 pediatric centers from 2010- 2013. Information was gleaned from 52,153 children with appendicitis. The use of ultrasound increased 46 percent, whereas use of CT decreased 48 percent. Surprisingly, despite the limitations of US, the percentage of negative appendectomy declined slightly (from 4.7 percent in 2010 to 3.6 percent in 2013) during the study period, and there was no change in the percentage of cases with perforated appendicitis or with ED three day return visits.

CT is an important tool for arriving at the correct diagnosis and guiding medical decision-making for many conditions in children. These studies suggest a shift to safer imaging modalities in children, with no adverse effects on outcome of appendicitis as found in one study.

What does this mean for your kids?

If your child ever needs an imaging modality to evaluate a medical condition, actively participate in the decision regarding which option to choose. Ask about the pros and cons of each modality so you can make an informed decision.

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