Recently, relatively small studies have suggested that contrast enhanced spiral computed tomography (CT) scanning is a useful diagnostic test for pulmonary embolism, with sensitivity as high as 80 percent and specificity as high as 95 percent. Spiral CT is widely available and much less invasive than pulmonary angiography. If spiral CT could be established as a useful diagnostic test, pulmonary embolism would be diagnosed more effectively and more patients would receive proper treatment.