Doctors may be using imaging tests too often to evaluate patients who possibly have pulmonary embolisms, according to a new study based on medical records from 5,940 emergency room patients. Details of the study from Harvard University researchers and others are published in the Archives of Internal Medicine and highlighted by MedPage Today. Among the conclusions: 32% of the CT scans or other imaging procedures used as part of an effort to diagnose pulmonary embolisms weren't necessary, and would have been considered "avoidable" based on a measure endorsed by the National Quality Forum, according to the story. Why weren't the tests needed? That's because 67% of the patients in the study hadn't yet had D-dimer testing. What's more, the D-dimer test had been done already and had negative results in 33% of the patients, the article notes. Story