Originally published in MedPage Today
by Chris Emery, MedPage Today Contributing Writer
Emergency physicians and radiologists overwhelmingly choose computed tomography (CT) imaging to diagnose pulmonary embolism, a potentially deadly blockage of lung arteries, a new study found.
Ninety percent of radiologists and 96% of emergency physicians use CT as their first-line choice for the diagnosis of pulmonary embolism, according to a report published online Dec. 22 in the American Journal of Roentgenology.
Other diagnostic techniques were used less regularly, with magnetic resonance imaging (MRI) used infrequently and ventilation-perfusion scintigraphy typically used in patients with renal failure or allergies to the iodine-based contrast material used for CT.
“The results of this study indicate that by a large margin, both emergency physicians and radiologists prefer CT in the diagnosis of pulmonary embolism,” Saurabh Jha, MBBS, of the Hospital of the University of Pennsylvania, and colleagues wrote.
A pulmonary embolism (PE) is a blockage in a lung artery, usually caused by a blood clot that travels to the lungs from a vein in the legs.
At least 100,000 cases of PE occur each year in the U.S., making it the third most common cause of death in hospitalized patients, according to the National Institutes of Health. About 30% of patients who have PE that goes untreated will die from the condition, typically within a few hours of the blockage occurring.
In recent years, advances in CT technology have altered the way many conditions, including PE, are diagnosed, and CT appears to be replacing catheter angiography as the standard diagnostic method, the authors wrote.
However, some situations — such as pregnancy or allergies to the contrast dyes used in PE — call for other techniques.
“The purpose of this study was to assess the imaging and general approaches to the diagnosis of pulmonary embolism in the usual and exceptional circumstances faced by emergency department physicians,” the authors wrote.
They surveyed 62 radiologists and 52 emergency room physicians at Pennsylvania hospitals using questionnaires about diagnostic strategies for the detection of PE, in both common situations and special clinical circumstances.
The respondents cited test accuracy as one of the major determinants of their choice, followed by overall access to CT, availability of 24-hour interpretation and capability for alternative diagnosis.
They found that in cases where women were pregnant and radiation exposure of greater concern, the approaches taken depended on medical personnel preference.
Emergency physicians favored ultrasound, while radiologists preferred nuclear medicine studies (ventilation–perfusion scintigraphy or perfusion-only scintigraphy).
While the use of MRI to diagnose PE was rare, the authors predicted that the technique will become more common.
“The potential benefits of MRI, even without exogenous contrast administration, are yet to be realized,” they wrote. “However, because emergency physicians have indicated that patient safety is a primary concern with regard to imaging, a role for MRI is likely to emerge.”
The researchers cautioned that they used surveys to collect the data used in the study, which could have biased the results.