When a test is too good: how CT pulmonary angiograms find pulmonary emboli that do not need to be found

For decades clinicians have been taught that pulmonary embolism—defined by the National Institutes of Health as a “sudden blockage in a lung artery”—always matters and to be vigilant because amissed embolism can be fatal.When a patient presents with shortness of breath, pleuritic chest pain, tachycardia, or signs of right heart strain, clinicians are trained to think “pulmonary embolism.” Because these symptoms and signs are neither sensitive nor specific, scoring systems (such as the Wells criteria) have been developed to help clinicians decide which patients to scan, although in practice, many clinicians simply proceed with imaging to confirm or refute the diagnosis. Explosion in use of CT imaging