A study by University of North Carolina at Chapel Hill researchers found that 31 radiologists who reviewed the CT scans used in a medical malpractice lawsuit didn't agree with the conclusions reached by four paid medical expert witnesses in the case.

This suggests that the use of radiologists who are blinded to both the medical outcome and the litigation in such cases may be a more objective way of determining whether the standard of care has been met, says Dr. Richard C. Semelka, lead author of the study and professor of radiology in the UNC School of Medicine.

"Our study shows that a new paradigm for determination of standard of care in malpractice cases is required, in order to stem the tide of increasing overuse of tests and to minimize the perceived risks of litigation among physicians," Semelka says. "Fear of litigation, and the practice of defensive medicine because of that fear, is the primary driving force behind overuse and waste in the U.S. health care system."

Publication of the study, in the August 2010 issue of the American Journal of Roentgenology, arrives as a fierce debate over medical malpractice reform that began more than 20 years ago and continues to rage in the U.S. It follows closely on the heels of a survey of physicians, published in June in the Archives of Internal Medicine, in which 91 percent of respondents said they believed that "physicians order more tests and procedures than needed to protect themselves from malpractice suits."

On the opposite side of the issue, plaintiffs' attorneys and other advocates for patients who have been injured by medical malpractice have argued with equal force and considerable success against many measures that have been proposed. One of those proposed measures is a cap on damages awards, to rein in the costs of malpractice litigation and discourage the practice of "defensive medicine."

In the study, Semelka and study co-authors sent images from six CT studies to 31 radiologists for interpretation. The cases were selected to simulate a typical hospital emergency department caseload. Two of the cases were major trauma cases. One of those had been the subject of a malpractice lawsuit that was settled out of court while the other was a similar case that hadn't been litigated.

One case was used as a control. The radiologists were blinded to both the clinical outcome of the cases and to the litigation, and each was paid $100 to review and interpret the CT images.

In the control case, all 31 radiologists correctly identified the findings. In the major trauma case that hadn't been litigated, 30 of the 31 correctly identified the findings.

In the case that had been litigated, there were three separate findings by the expert witnesses of vertebrae injuries that the radiologist in the lawsuit was alleged to have missed. None of the 31 reviewing radiologists in the study identified those injuries in two of those three findings, including the injury that was considered critical in the litigation. In the third finding, 19 of the 31 reviewing radiologists identified the same injuries as the expert witnesses.

"This result illustrates an intrinsic flaw in the current medicolegal system that specifically affects radiologists," the study concludes. "This finding prompts questions about the current method of determining standard of care in legal cases, that is, use of paid medical expert witnesses.

Our findings suggest that use of radiologists blinded to clinical outcome may be a more objective method of evaluating legal cases."

Co-authors of the study were Andrew F. Ryan and Shannon Yonkers, of UNC, and Dr. Larissa Braga, from the University of Nebraska Medical Center.