July 2011

CT in the ER — Radiologists and Emergency Physicians Often See Radiation Risks and Benefits Differently
By Thomas G. Dolan
Radiology Today
Vol. 12 No. 7 P. 16

In a study published this past January in Radiology, researchers cited data from the Centers for Disease Control and Prevention showing that the use of CT increased from 2.7 million scans performed nationwide in 1995 to 16.2 million in 2007. In a subsequent article published online in April, it was reported that, during approximately the same time period, CT procedures involving children increased from 330,000 to 1.65 million. It was also found that during this time, the use of imaging technology in emergency departments (EDs) increased an average of 16% annually.

These data raise questions about unnecessary radiation exposure and increased cancer risk. However, among the four authorities interviewed for this article, there is little consensus on what, if anything, should be done differently when it comes to CT scans, especially in the ED.

“Other studies have shown that in children’s hospitals and university settings, the uses of ultrasound and MR have increased while that of CT has actually decreased,” says Donald P. Frush, MD, FACR, chair of the ACR Pediatric Imaging Commission and chief of pediatric radiology at Duke University Medical Center in Durham, N.C. “The data has varied. It depends what you are looking for.”

David B. Larson, MD, an assistant professor of radiology at Cincinnati Children’s Hospital Medical Center in Ohio, says fast, useful images are a major reason for CT’s growth. “One of the primary drivers is the improvement in the technology. You get high resolution available very quickly,” says Larson, who was a coauthor of the articles in Radiology.

He says other possible reasons are that ED personnel are seeing more serious cases than in the past. And notably, CT scans cost less but have a high margin of profitability.

Frush adds that the recent trend of physicians including patients in the decision-making process, especially parents, has apparently led to parents asking for CT scans rather than being cautious about the possible harmful effects of radiation. Stephen Amis, Jr, MD, FACR, chair of radiology at Albert Einstein College of Medicine and Montefiore Medical Center in Bronx, N.Y., and past president of the ACR, adds that “most people say they don’t care about radiation. They demand the CT scan.”

ED Pressure
Perhaps the most compelling factor driving the increased use of CT is the pressure on emergency physicians to make quick, accurate diagnoses, according to the sources interviewed for this article.

“They [doctors] are driven by the huge number of people who come to the emergency room,” Amis says. “They have to quickly evaluate the person and get him out the door or admitted to the hospital. The CT scan takes about 15 seconds. These physicians are under the pressure of the Emergency Medical Treatment and Labor Act passed in 1986, which basically says that if a patient comes to an emergency room, it’s incumbent the physician finds nothing is wrong. If a serious disease or condition shows up afterwards, the physician can be fined big time. And that’s accompanied by the greater fear of a malpractice suit.”

It does not appear that any particular disease or condition is causing the increase in CT scans. For instance, Larson says that over the past four years, CT scans for abdominal pain in children have increased 15% to 25%, but there has not been a rash of food poisonings or other factors leading to a corresponding increase in scans for stomach disorders.

“There are more elements of research to be done,” Larson says. “It appears that higher dosages of radiation are ahead. But the most important questions are not contained in the data, whether it’s a good thing or bad. We don’t know. It’s a very subjective question. What we conclude is that it’s something we should keep our eye on it so if, at some point, we are overutilizing it [we can cut back]. Now, however, if we presume it is a risk, it’s a theoretical risk and very low.”

When asked whether the actual increases in radiation exposure represent more than a theoretical risk, Larson says, “Personally, I don’t take a position either way. Either theoretically or actually, the actual risk is low. Estimates [of cancers caused by medical radiation exposure] range from one case in several thousand to one in 10,000 leading to cancer death. So I don’t believe there’s a reason to encourage people not to take this procedure.”

Frush acknowledges that the numbers showing a general increase in CT scans deserve attention. “And these numbers should make us more attentive to what we are doing to justify the examination so we only perform those which are clinically warranted,” he says.

Frush adds that the exams should be individualized as much as possible, taking into consideration various factors such as age, gender, and the size of the area being imaged.

But he also says the increased use of CTs has often been justified for its aid in correctly diagnosing, in a timely fashion, conditions such as appendicitis, spinal trauma, and blood clots in the lungs.

When to Worry
At what point should people be concerned about radiation exposure from CT exams?

“I don’t believe we know that for certain,” Frush says. “Some believe the threshold is lower than others, and there is no agreement as to what the lowest level of risk is, for there are different numbers promoted by different parties. Now we need to make sure we have the proper utilization so that the public and patients know what that is. But I believe the benefits generally far outweigh the risks. Almost all chest x-rays, whether one or several, are far from the risk threshold. And one or two exams of even very young children should not be a concern to parents.”

Frush adds that even a CT scan that does not reveal evidence of a medical problem “should not be considered needless radiation. Such information can be extremely helpful in terms of management decisions, and it might be tremendously reassuring to the patient. People need to understand that if stress reduction is a component of that exam, that it was not a wasted one.”

Howard Blumstein, MD, FAAEM, president of the American Academy of Emergency Medicine and vice chair of emergency medicine at Wake Forest University in Winston-Salem, N.C., says there are two key areas of discussion when it comes to CT in the ED: the damaging effects of radiation and efforts to address that exposure.

“Just 15 to 20 years ago, we were told the risk of getting cancer from a CT scan ranged from one in 1,000 to one in 2,000. Now we are told the risk from dying of cancer ranges from one in 100 to one in 200. But I don’t know of any expert opinion that tells you how to figure it out. Certainly there are differences between giving a CT exam to a 100-year-old and a baby who will carry a lifelong risk. There are only crude estimates based on studies of victims from the atomic blasts in Japan in World War II and at Chernobyl.”

Blumstein adds that research does show a dramatic increase in imaging exams, saying, “What troubles me is that the risk estimates keep getting worse and worse.”

To address exposure concerns, Blumstein points to the joint project among the American Board of Medical Specialties, the American Board of Radiology, the ACR, and the American Medical Association to produce a guidance document on 15 or 16 measures to minimize the amount of radiation used in imaging. (A public comment period on the document concluded as this issue was in production.) Some of the measures, Blumstein continues, are not controversial, and he has no trouble accepting them. These include putting imaging studies into formats other practitioners can use, a hospital utilizing a CT scan it has already done on a patient instead of ordering another, and special protocols for children so they do not receive adult dosages.

Different Viewpoints
Blumstein says he does not like the idea of radiologists forcing their findings on emergency doctors. “We don’t think it’s appropriate for one group of specialists to approve practice standards for others,” he says. “It’s like determining how to build a better airplane and not talking to the pilots. If you read their measures, they don’t take into account a lot of the measures involved in ordering these exams.”

Blumstein’s complaint involves inclusivity, not whether the recommendations are wrong. “For instance, they ask questions about whether it’s appropriate to get a CT scan for headaches, but for a large number of patients, this would be appropriate, whereas the guidelines say it’s not. I am thinking of hydrocephalus, or buildup of pressure in the brain, where such scans would be absolutely appropriate.”

Instead, he has stronger criticism for the manner in which the Centers for Medicare & Medicaid Services (CMS) has recently commented that EDs have been ordering too many head CTs.

“For the past several years, CMS has been correcting the data of individual hospitals,” says Blumstein. “CMS is attempting to improve monetary efficiency, so they’ve started posting their dry run data on their website. And, lo and behold, one of their recent issues has to do with the use of brain scans. CMS said that 35% of the scans for traumatic headache were inappropriate. This is even worse than the optimization project. Their calculations are totally unfair. I think they’re crazy.

“Radiation does appear to be more dangerous than we used to think it was, but the pressures to reduce them are unfair,” he continues. “The question is how to reconcile the two. I do believe the medical community as a whole, and not just emergency rooms, order too many CT scans. Sometimes a patient in emergency may not want a CT scan but a doctor not in my department orders one, which means it’s a bit unfair to focus just on emergency doctors.”

Utilizing imaging modalities that do not expose patients to ionizing radiation are one way to reduce exposure, but MRI and ultrasound are not always available or appropriate for the imaging need.

“It depends on what you are looking at,” Blumstein says. “They may or may not be appropriate substitutes. Gallbladder always gets an ultrasound. In a perfect world, the right test would always be administered. But there are a number of other realities that make the world less than perfect. Many hospitals have CT scans available 24/7 but not ultrasound, and sometimes radiologists at hospitals prefer CT to ultrasound for whatever reason. My feeling is that I treat my patient as I would myself.”

When asked whether he would submit to a CT scan, Blumstein says, “If I have a patient I think needs it and I get the same condition myself, absolutely. I’m not trying to say never do a CT scan. It’s up to the physician. I think sometimes physicians think about the potential benefits and not the risks. They don’t balance the two out.”

Legal Threats
Amis expresses empathy for the pressure ED doctors are under with the huge press of patients who need to be diagnosed quickly as well as the threats of fines and/or lawsuits for missing serious conditions, but he offers a different perspective.

“In 2007, we started a blue ribbon panel of the National Council on Radiation Protection and Measurements and attempted to convene the leadership of emergency medicine and radiology to confront the problem of increased radiation. But there was not much common ground. We’ve developed more extensive guidelines, and are still developing them, for the best way to image. But since they’re being developed by radiologists, it appears that most of what we offer is considered not appropriate by emergency room physicians. The consensus is not working.”

There are some measures Amis believes can and should be taken. The first is decision-support software on hospital computers to help determine whether a particular imaging exam is indicated. In addition, software or some other method of tracking a patient’s previous imaging would be valuable. Electronic medical records and other imaging IT vendors are working on ways to track and share patients’ imaging histories, but as Amis pointed out, implementation of a nationwide CT database “is still a long, long time away.”

Nevertheless, Amis maintains there is enough information out there showing that, beyond conflicting reports, theory, and rough estimates, too many people are being subjected to too much radiation. Amis mentioned research showing that some patients in one study group received up to 132 CT scans, which he calls a “ridiculous” number.

Moreover, Amis maintains that the analyses of the radiation fallout from Chernobyl and Japan are more specific to medical exams than rough extrapolations from nuclear explosions.

“The measure of an absorbed dose that can be dangerous from any source is about 50 mSv,” Amis says. “The definitive study on this issue was in an article by Brenner and Hall published in The New England Journal of Medicine in 2007. They estimated that 1.5% to 2% of all cancers are due to CT scans alone, which came to 28,000 new cases of cancer every year.

“I really strongly believe in the risks of excessive radiation,” Amis adds. “At our institution, we cut the number of CT exams by 5% last year.

“Radiology and imaging have revolutionized medicine,” Amis notes. “CT scans can be a wonderful test but only when really indicated. Every doctor should think about the risk-benefit ratio for the patient.”

— Thomas G. Dolan is a freelance writer.