In 1980, 3 million computed tomography (CT) scans were performed in the U.S. In 2007, nearly 70 million were done. “We're higher [in our use of CT scans] than almost any other industrialized country,” said Rebecca Smith-Bindman, MD, professor in residence of radiology, epidemiology/biostatistics, and obstetrics, gynecology, and reproductive medicine at the University of California, San Francisco.
“There's remarkably little research that has tried to quantify what we are getting out of this. How much of this imaging is helping patient care? How much of it may be completely unnecessary?” she added.
Recent studies, by Dr. Smith-Bindman and other researchers, have raised concerns among physicians and the public that this heavy use of CT scanning could actually lead to some negative, instead of positive, health consequences for patients.
“It's not clear that patients are having better outcomes, better health, which suggests that at least some of those tests probably didn't need to be done,” said Rita Redberg, MD, a cardiologist and professor of medicine at UCSF.
The issue of possible overuse of CT technology is currently attracting attention from payers, regulators and politicians, but may be dealt with most simply, and perhaps most effectively, by the decision making of individual physicians, experts said.
Why not to scan
Several potential negative effects of overuse have been identified. The risk of radiation-related cancer has been the most heavily publicized. A December 2009 study in Archives of Internal Medicine projected that as many as 29,000 excess cases of cancer could result from CT scans performed in 2007.
The risk would result not only from the number of scans being performed, but also from the dose of radiation in each, which can vary widely (an average of 13-fold) by facility, according to a study by Dr. Smith-Bindman published in the same issue of Archives.
“The radiation from those studies in general is going up. Now you have a much higher proportion of patients exposed, a higher proportion of tests. The result is a pretty dramatic increase in the radiation exposure that the population experiences,” Dr. Smith-Bindman said.
Not all experts are convinced that this radiation exposure is likely to have negative health effects. Researchers' assumptions about the relationship between radiation and cancer are drawn from atomic bomb blasts, said Bruce Hillman, MD, professor of radiology at the University of Virginia in Charlottesville.
“What radiation physicists have done is to back-project that correlation to zero level of radiation and make the assumption that radiation is cumulative and if you get lots of CT scans, even though each one is a small dose, that that's an accumulated risk…and also that radiation at any level increases your chances even very slightly of getting a cancer down the line. That's what we live by, even though there's little direct data to support that,” he said.
The risk of cancer would vary depending on the body part and the age of the patient being scanned. “Younger patients are going to be more sensitive to exposure. Certain organs with rapidly dividing cells are going to be more sensitive to radiation,” Dr. Hillman said, citing testicles, thyroids and breasts as examples.
Regardless of interpretation of radiation risk, there are other reasons to be concerned about excessive use of scanning. “I don't think there's any question that the biggest risk of doing an unnecessary CT scan is an incidental finding that will lead to more invasive treatment,” said Howard Brody, MD, a family physician and director of the Institute for Medical Humanities at the University of Texas Medical Branch in Galveston.
However, the risk of these “incidentalomas” has not captured the public's attention as radiation risk has. “If you try to explain to the patient, ‘You could get cancer from the radiation,’ right away the patient knows what you're talking about. If you try to explain, ‘You know I might find an incidental finding and then this might happen and that might happen and this might happen and then you might be harmed,’ it's really hard for the patient to grasp that,” Dr. Brody said.
Unnecessary follow up and patient harm can also result from scans that come back with false-positive results. Then there's the consequence that drives payers to be interested in the issue—unneeded exams obviously contribute to skyrocketing national health care costs.
“When you order an inappropriate exam, there's nothing good that can happen of it,” said Dr. Hillman. “The general estimate is that as many as a third of all imaging exams do not contribute to the care or the outcome of the patient. There's no data to support that number, but certainly it's a sizable fraction.”
Why so many?
A number of factors push physicians toward ordering scans when they're not needed, the experts said. For one, imaging has become a standard part of medical culture. “It's become expected that you're going to get an imaging test. The patient wants it, the referring doctor wants it, the specialist wants it,” said Dr. Smith-Bindman.
Patient desire for imaging often results from a misunderstanding of the quantity/quality equation, according to Dr. Brody. “A lot of our patients are just used to the idea that more is always better, that if my doctor orders lots of tests…that means my doctor really cares about me and I'm really getting the very best medical care,” he said.
Direct-to-consumer advertising by the manufacturers of scanners encourages this assumption, said Dr. Hillman. “What in the world is GE, what in the world is Siemens doing showing their CT scanners on television? They do that because they know that patients greatly influence physicians.”
Manufacturers aren't the only ones who gain financially from CT scans. “Imaging is extraordinarily profitable. It's profitable for the institution, for the emergency department, for the hospital, for the radiologists, for the urologists that own their own machines,” said Dr. Smith-Bindman.
Not scanning, on the other hand, can be costly in a different way, especially for hospitalists who need to maintain high productivity. “It's a whole lot easier to first do the test, and find out if there is a problem and then contact the appropriate specialist, than to first contact the specialist, have the specialist see the patient, and then get the CT,” Dr. Smith-Bindman said.
“Sometimes it's just easier to say, ‘I guess I'll get an imaging exam, because it would just take me too long to continue to listen to this very hard-to-understand story or actually do a physical exam,’” described Dr. Hillman.
The simplest solution to the problem of overtesting is for physicians to slow down and think, the experts said.
“There are times that we'd do just as well with clinical assessment—a good history and physical without an imaging test,” said Dr. Redberg. “It's important for any particular test to think about: Do I really need the information from this test? How is it going to change my plan? How will it lead to a different or better outcome?”
For doctors not certain of the answers to those questions, there may be an expert nearby who can help, said Dr. Hillman, who takes issue with the description of generalist physicians “ordering” a CT. “It's gotten to be too much ordering and too little consultation. If there's ever a concern about that ratio—the long-term downstream risk of getting an imaging examination versus the benefit to the patient—a formal consultation, not just sending in the form, but a conversation either by email, or on the telephone or in person, with an expert, a radiologist, is really what ought to occur.”
There are also lots of alternative tests, other than CTs, that may be worth considering—treadmill testing or echocardiograms for cardiac issues, MRIs for some conditions. “Ultrasound scans are grossly underutilized in this country because physicians mostly can't read them as they can with the images on CT scans,” said Dr. Hillman, noting that the ultrasounds are also less cost-effective for radiologists.
Radiologists can present a potential solution to the problem of incidentalomas. “A good radiologist will tell the physicians these exist, but will also tell him or her that these have no importance to the patient,” said Dr. Hillman. “They should work with radiologists who understand that overcalling things is just as serious a problem or perhaps more serious a problem than missing things.”
In some cases, it may also be appropriate for physicians to share some of the decision making with patients, especially if they're on the fence about whether a patient needs the scan. “I might say, ‘Here are the pros of getting a scan. Here's the downside. Which do you think is more important?’ If…some patients request a CT scan and some don't, and they know what they're getting into, because we've informed them properly, that's an ideal decision-making mode,” said Dr. Brody.
Properly informing patients about the risks of scanning is a responsibility of the physician ordering the test, he noted. “We have to be upfront and warn our own patients and be part of the disclosure process in the office, not just put it all off on the radiology department,” Dr. Brody said.
There are some aspects of the CT problem that hospitalists likely can't take on themselves, for example the variation in radiation doses. In some highly publicized recent incidents, patients were found to have received much higher doses of radiation than was appropriate. In response, a recent California law requires radiation doses to be recorded in patients' medical records, but Dr. Smith-Bindman doesn't think the situation will be resolved so simply.
“The manufacturers have made it nearly impossible to get this information out of the machines and into the medical record,” she said. “I'm not sure how most practices in the state are going to respond. They're in a state of panic because these data are very much hidden.”
She'd like to see either regulation or guidelines setting out acceptable doses for routine studies, and recently proposed a metric to the National Quality Forum that would help practices voluntarily review the doses they use for routine CT study types. “Alternatively, the FDA could get involved in setting standards, but they are very reticent about getting involved in legislating medicine. But they do [have standards] for mammography, so there is a precedent of their getting involved in quality improvement around the conduct of imaging.”
The FDA did recently offer some recommendations to CT scanner manufacturers on how to reduce the risk of patients receiving excess radiation, particularly from brain perfusion scans. The agency's suggested changes include making dose-related information clearer and more accessible.
As for the issue of the quantity of scans, physicians need to take the lead by trying to make cuts before it's done more aggressively by payers, said Dr. Brody. “They're going to be forced to take action. It will be a much less surgical and much less precise way to cut costs and everyone will suffer,” he said.
Debate about direction
Although CT rates remain high, growth has slowed in recent years. “The rate of rise of CT scanning has leveled off. CT scanning was far outpacing general medical inflation from the year 2000 through 2005, but actually was lower than general medical inflation in 2008,” said Dr. Hillman.
The recession may have had an effect on scanning rates, and reduced reimbursement for the technical fees for scanning, enacted by Medicare in 2005 and cut even further in 2010, may also have decreased physicians' eagerness to scan, Dr. Hillman speculated.
He also suspects that fears of radiation, which he thinks have been excessive, have influenced scanning rates. “Some patients now, when their physician says ‘CT scan’, even if they need it, they may actually say, ‘No thanks, Doc,’” Dr. Hillman said. “Right now the pendulum has swung, I think, way too far, in that people are very afraid of what amounts to very low risk compared to the benefits of a needed exam.”
Yet, from Dr. Brody's perspective, that pendulum is still on the other side. “It would take us so long before we got anywhere near [underusing medical technology]. The pendulum in medicine is so far the other way.”
Experts in both camps could likely agree, however, on Dr. Hillman's overarching piece of advice. “Ordering CT scans should always be a consideration of how much risk there is against the value of the information that you're going to get by ordering the scan,” he said.