Diagnosing the Diagnostics

New findings on radiation exposure from imaging tests

The standard procedure for physicians when diagnosing illness is to confirm its presence with state-of-the-art tests. In today’s technologically advanced world of medicine, those tests often include imaging studies that utilize radiation. Now, after a recent study on the levels of exposure to radiation from such tests in the U.S., a change in protocols may be needed.

“We decided to research this topic because of the rise in medical imaging,” says Brahmajee K. Nallamothu, M.D. (Fellowship 2004), an author of the study who is a U-M associate professor of internal medicine and a staff cardiologist at the VA Ann Arbor Healthcare System. As a clinical researcher, Nallamothu recognized the need to examine the use of these tests on patients throughout their lifetime.

“Rarely do patients undergo a single examination,” he says. “If you have chest pain, for example, it’s likely that you’re going to get more than one test, such as a stress test and possibly a cardiac catheterization. We approached the research by asking: If a single test in one person has a certain associated risk and is raising concerns, how many of these tests are occurring or being repeated in the same patient over longer periods of time?”

“There are a number of studies showing that many physicians aren’t even aware of this issue,” adds Reza Fazel (M.D. 2001, Residency 2004), lead author of the study and a cardiologist at Emory University. The study also included colleagues at Yale, Columbia, Mayo and Johns Hopkins, and was published in the New England Journal of Medicine in August.

In the study, nearly 1 million adults age 18-64 from five health care markets across the U.S. were identified from UnitedHealthcare claims data. The utilization data from this group from 2005-07 was used to estimate cumulative effective doses of radiation from imaging procedures. Exposures were estimated using the concept of effective dose, which is expressed in millisieverts and reflects how harmful a given exposure is to the body.

Computed tomography (CT) scans were among the procedures exposing patients to the largest amounts of radiation. CT scans constituted only 16 percent of all procedures, but accounted for nearly 50 percent of the total exposure to patients.

Even before this study, the U-M was leading the charge to improve safety by justifying the use of each procedure, seeking alternative methods that might be safer, and minimizing radiation exposure during imaging.

Fazel and Nallamothu recommend that patients take an active role in reducing their risk by understanding why their physician is recommending a procedure, asking if there are safer alternatives, and requesting that the facility providing the imaging be certified for safe operating procedures.

Nallamothu stresses that imaging tests are a vital, lifesaving part of medical care. “Our study isn’t about eliminating imaging tests,” he says. “It’s about using them better — that is, only when necessary and in the best manner possible to reduce the risks to patients.”
—NICK CHARLES

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A New View of the Safest Hospitals for Surgery

A new U-M study overturns a long-held convention that the safest hospitals are those with the lowest complication rates. The study found that after major surgery, complications happen in about one out of six patients, a rate that remained fairly consistent among the 186 participating hospitals. It was what happened after the complication that mattered.

“The general assumption has been that high-mortality hospitals simply have higher complications rates,” says John D. Birkmeyer, M.D., the George D. Zuidema Professor of Surgery and chair of surgical outcomes research at the Medical School. Birkmeyer, along with lead author Amir Ghaferi, M.D., a surgical resident, and Assistant Professor of Surgery Justin Dimick, M.D., found that low-mortality hospitals are those with teams that are most proficient in rescuing patients from potentially catastrophic complications. Despite similar patterns in complications, patients treated at high-mortality hospitals were nearly twice as likely to die after a serious post-surgical complication.

The study used data on 84,730 patients undergoing general and vascular surgery at hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program. The mortality rate varied dramatically, from 3.5 percent at the best hospitals to 6.9 percent at the very high-mortality hospitals. Birkmeyer says the study shows that “Rather than focusing only on what the surgeon does in the operating room, we need to focus on what’s happening on the wards and in the intensive care unit afterward.”
—RK

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Health Briefs

When tissue or blood type incompatibilities prevent a willing friend or family member from donating a kidney to a transplant patient, new U-M software seeks to match that pair with other pairs in the same situation. The match enables the donor from the first pair to donate to the recipient from the second pair, and the donor from the second pair to donate to the recipient from the first pair.

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Cheerleading is the leading cause of catastrophic injury among young female athletes today, according to Amy Miller Bohn, M.D., assistant professor of family medicine. Data show that injury rates rose from nearly 5,000 in 1980 to close to 28,000 in recent years. Bohn says cheerleading is now a competitive sport with increased difficulty and risk for serious injury, and that more safety measures and supervision are needed.

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Medical School researchers will lead a $10.25 million collaboration among 15 academic medical centers and the Nephcure and Halpin foundations to study rare kidney diseases that lead to kidney failure and the need for dialysis. Known collectively as nephrotic syndrome, the diseases, while rare, contribute to nearly 12 percent of kidney failures at an annual cost of more than $3 billion.
—RK

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