PACS reduces emergency department misdiagnosis rate

Use of PACS in the hospital emergency department improves diagnostic performance by the emergency staff, according to a study published in the May Journal of Accident and Emergency Medicine (2000;17[3]:180-184).

The study found a significant decrease in the overall rate of misdiagnosis by emergency physicians when PACS was used in the accident and emergency (A&E) department of Hammersmith Hospital in West London, one of the largest hospital trusts in the U.K. Failure to interpret radiographic images correctly had been a cause of diagnostic error and litigation.

"Misdiagnosis in the A&E is apparently a common and potentially serious problem," said Dr. Gwyn Weatherburn, lead author and a research fellow in the Health Economics Research Group at Brunel University, Middlesex, UK. "Previous studies have found the misdiagnosis rate by A&E staff ranges from 0.6% to 7%."

Weatherburn conducted her study in two parts:

?First, while the hospital was still using conventional film-based radiology;
?Second, after a GE hospital-wide PACS was installed.

For each part of the study, the diagnoses of radiographic images made by A&E clinicians were compared with those made by radiologists, to determine the incidence of false-negative findings by emergency physicians.

The management of patients with such findings was then studied to identify those for whom a change of treatment was required. The data for the two periods, film versus PACS, were then compared. While the overall rate of misdiagnosis across all A&E radiography patients was low in both periods, there was a 50% reduction in misdiagnosis when PACS was used (1.5% for film and 0.7% for PACS), Weatherburn said.

In Hammersmith's A&E, as in many U.S. hospital emergency departments, radiographic images are often used to determine initial diagnosis and patient treatment management. Emergency physicians are frequently unable to obtain immediate support from radiologists and therefore have to rely on their own interpretation of images.

"This means that junior members of Hammersmith's medical staff with limited radiologic training or experience may have to interpret images without access to a radiologist's report 16 hours per day during the week and 24 hours a day on weekends," Weatherburn said.

Weatherburn attributed the positive influence of PACS to the various tools it makes available to clinicians that allow them to manipulate soft-copy images, including variation of the gray scale and contrast, and zooming to increase the resolution of image details through magnification.