Between 1995 and 2008, the number of pediatric visits to an emergency department (ED) that included computed tomography (CT) increased fivefold, according to study results published online ahead of print by the journal Radiology. The researchers, led by David B. Larson, MD, MBA, Director of Quality Improvement in the Department of Radiology at Cincinnati Children’s Hospital Medical Center in Ohio, say the substantial growth in CT use “is explained by increasing frequency of use, not by an increase in the number of pediatric visits to the ED.”
Larson and colleagues also reported that about 90% of the visits associated with CT in children were made to nonpediatric-focused EDs (ie, those in which the average patient was older than 10). Given what is understood about the increased risks of radiation exposure in children, this finding raises additional questions and concerns about whether children received a radiation dose that was scaled to their body size or an adult dose. (The study was not designed to assess that.)
Whether to order CT in a child may be a daunting proposition for a clinician, particularly if he or she does not have subspecialty training in pediatrics. Ordering an unnecessary test may needlessly expose the patient to radiation, but missing a diagnosis that results in a negative outcome is also fraught with peril.
“This is the fine line that we walk in this conversation: On the one hand, CT uses radiation, so we should use it cautiously,” Larson says. “On the other hand, the risk is very low, and we don’t want to scare people out of getting CT.”
Boom Years for CT Use
The National Cancer Institute reports that four to seven million CT exams are performed in children annually in the US, and that the use of CT (in both adults and children) has increased significantly since 1980, growing at an estimated rate of 10% per year. Larson attributes much of the increase observed in his study—an annual growth rate of about 13%—to the fact that the technology “improved significantly” during the time period examined.
“This is a time when the technology moved from basically axial scanning to helical scanning, and also from single detector to multichannel detectors,” he says. “So, that translates into a much faster scan and a much higher-resolution scan. This is especially important in children, because it means less sedation, and in the ED, it means you can come to a decision very quickly.”
Another factor driving the increased use of CT has been the ready availability of the equipment. A decade ago, major hospitals might have had a scanner, but it was not necessarily located adjacent to, let alone within, the ED. Smaller facilities may not have had a scanner, period.
“The availability of CT has increased exponentially over the past 10 years, and it has been a very reliable diagnostic tool,” says John J. Graykoski, MPAS, PA-C, President of the Society of Emergency Medicine PAs and ER PA Supervisor at Luther Midelfort Mayo Health System in Colfax, Wisconsin. “It has tremendously enhanced our ability to identify problems much earlier and with much greater accuracy than our old plain films could do.”
Speed and accuracy are particularly valuable in the emergency department, where, in the words of Michael P. Poirier, MD, Associate Professor of Pediatrics, Eastern Virginia Medical School, and Fellowship Director, Division of Emergency Medicine, Children’s Hospital of the King’s Daughters, Norfolk, Virginia, “you have one chance to get it right.”
That time pressure to make an accurate diagnosis, coupled with the ever-present fear of litigation if the wrong decision is made or a negative outcome occurs despite the clinician’s best efforts, may lead to the ordering of a CT scan that is not truly necessary. The prevailing wisdom might be “It’s better to rule out the worst-case scenario and have that reassurance than to take the chance of missing something.”
The drawback to that philosophy is that CT uses radiation—more of it than the average x-ray. The effective dose of radiation in the average CT scan of the head is equivalent to approximately 100 x-rays and in the average abdominal CT scan, 400 x-rays. Granted, these doses are from scans that are unadjusted for body weight, and in theory children should be undergoing CT with reduced radiation exposure parameters. Whether they actually are, particularly at nonpediatric facilities, is unknown.
“We hope that at all facilities, whether they are pediatric-focused or not, the dose is being tailored to the patient’s size,” Larson says, “but we don’t know. We know that it has [improved] at children’s hospitals; that study just hasn’t been done at non-children’s hospitals. I think the concern is that right now, it’s actually rather difficult to monitor that.”
At Graykoski’s facility, which is not pediatric-focused, the staff is “acutely aware of this issue.” Consultations with the radiologist prior to the ordering of scans are common, protocols are in place to limit the amount of radiation exposure in CT scans, and the newest-generation equipment, which has built-in capabilities to limit exposure, is available. “We’re trying to do everything we can to make sure that the risks associated with imaging are offset by the benefits to be realized from it,” Graykoski says.
The National Cancer Institute stresses that “the individual cancer risks associated with CT scans are small,” with lifetime risks estimated at less than 1 in 1,000. However, as the data indicate, children are increasingly being exposed to those risks, and they may be particularly vulnerable. “From age 0 to 14 especially, the DNA is rapidly replicating, and that’s when it is most vulnerable to insult from radiation,” Graykoski explains.
Furthermore, “the risk of radiation is a cumulative lifetime risk. It’s not the case that you just take a picture and in 24 hours, the side effects are gone,” he adds. Young children have the rest of their lives to accumulate radiation exposure from additional imaging tests and from natural circumstances. (The average effective dose of natural background radiation is 3 mSv per year in the United States.)
“It’s not that we have the crisis right now—this is a problem that will be growing into the future,” Graykoski says, especially if the boom in the use of this imaging modality does not abate. “And of course, our concern is for safety—we don’t want to be responsible for causing harm to any patient, especially a youngster.”
First, Do No Harm
Any clinician who is considering ordering CT for a pediatric patient may want to paraphrase a classic World War II adage. Instead of asking, “Is this trip really necessary?” the question should be, “Is this test really necessary?”
As with any type of test, the decision to order CT should be made after careful consideration of the risks and benefits, as well as how the specific test will change the clinical management of the patient. Will the child be able to go home? Will he/she require an operation? Will the child need to be admitted?
Health care providers “need to be absolutely sure that the results of that test are actually going to help them make a decision or a diagnosis,” Poirier says. “And if time will help you make a diagnosis and does not put the patient at risk, then sometimes you don’t do the test. You talk to the family, and maybe you admit the patient or maybe you have them follow up the next day.”
A classic example is a child who has experienced head trauma; perhaps he or she was stunned at the time of the event or had an episode or two of vomiting. “It used to be pretty routine that all of those kids would get CT evaluations,” Poirier says. “The recent studies have shown that those CT scans don’t change the management of those patients. It’s just unnecessary radiation.”
Instead, it may be more appropriate to watch the patient in the ED until it is clear his/her condition is not going to deteriorate, ensure the family has adequate follow-up, or even keep the child in the ED or admit him/her for overnight observation. Of course, there are geographic factors to consider as well.
“A lot has to do with the comfort level of the parents—are they comfortable waiting and watching? Is it convenient?” says Graykoski, whose facility is in west-central Wisconsin. “We have patients who are two hours away from the hospital, so it’s not the easiest thing to say, ‘Well, go home; if it gets worse, bring him back.’ A couple of hours can certainly be very serious.”
Communication is key so that parents have a full understanding of why an imaging study may or may not be in their child’s best interest. Despite reports in the mainstream media about the radiation risk of CT, none of the clinicians interviewed has yet encountered parents who refused CT because of that risk. Graykoski says he is usually the one to broach the subject with parents.
“Most parents, I think, want to hear that discussion,” he says, “but I would say the majority want the reassurance of having some of these tests done and frequently will err on the side of getting that information and ruling something out, as opposed to thinking about the future effect of radiation accumulation.”
In the pediatric emergency setting, Poirier says it is more likely that the clinicians will utilize the available information to talk families out of getting an unnecessary test. “They may come with preconceived expectations,” he says. “Maybe they were sent from the adult facility or from another provider because they ‘need’ this head CT or they ‘need’ that abdominal CT—and in fact, they don’t. We very frequently explain to them that we don’t want to expose the child to any unnecessary radiation, and therefore, we don’t think this test is necessary.”
How significant a role “defensive medicine” plays in the decision-making process is unclear, although studies have shown that the fear of litigation increases utilization of all imaging, not just CT. The fear of being sued for missing a diagnosis could someday be countered by the fear of being sued for exposing a child to radiation unnecessarily—a rock/hard place debate if ever there was one.
“All you can do is apply the best information you have with your best clinical judgment and try to do what’s right for the patient,” Graykoski says, “and hope that in 20 years some lawyer doesn’t come knocking on your door, saying ‘pay up.’ But I think for all of us, our motivation and training is ‘first, do no harm,’ and we all take that very seriously.”
Will CT one day be a diagnostic modality for which informed consent is universally required? Or will advances in technology continue to occur, producing safer scanners? Larson, for one, defends the judicious use of CT, saying, “It keeps getting better and better, and the manufacturers are continuing to decrease the radiation dose. So I expect it’s going to continue to be important for a long time.”
As technology improves, other modalities may emerge as more valuable diagnostic tools in certain situations, providing alternatives to CT. “I think in the next 10 to 15 years, we’re probably going to be shifting to high-speed MRIs, which don’t have the radiation exposure,” Poirier says. “And we’re going to look back at this time, in the ’80s and ’90s, when the use of CT scans basically just exploded, and we’re going to be dealing with the consequences.”
Graykoski also points out that ultrasound “is becoming a viable alternative to CT in the case of appendicitis. The key now is training the ultrasonographers and having the quality in place to ensure that the accuracy is at a point where it should be.”
Clinicians should also remember that the radiologist is another partner and a valuable human asset in patient care. He or she should be reviewing the orders, particularly the indication for the request, and may follow up if the order doesn’t make sense.
“Try to avoid becoming defensive and understand that the radiologist usually views himself/herself as a last stand in confirming that this is an appropriate examination,” Larson advises. “Often, the radiologist can offer alternative imaging or talk the clinician through a case that is on the margin in terms of whether CT is indicated.”
Deciding whether to order CT in a child is about striking an appropriate balance. “On the one hand, we might say, ‘If you don’t need the CT, don’t get it,’ or ‘If there is a reasonable alternative, then go with that reasonable alternative,’” Larson says. “On the other hand, if there is a serious or life-threatening illness or injury, or a case where you really need that information, then the parent and the clinician should absolutely just get the CT and not give it a second thought.”
Poirier thinks there is a place for observation and for ruling out life-threatening and dangerous diagnoses, “but there’s also a place for having an unknown and letting time help you decide, with close follow-up and appropriate observation. And therefore, sometimes you are able to avoid performing one of these tests. You’re going to get the same information; you’re just going to get it a little later. That’s the art of medicine—knowing when to order it and knowing when not to.”
“The bottom line is that medical science is a human science, and there are no absolutes,” Graykoski says. “You can do your best, but you cannot predict the future. We graduate and get a stethoscope; we don’t get a crystal ball.”