WHY do a lung scan—a question asked by physicians in many types of practices, and with good reason. If a lung scan is being considered to confirm or exclude the diagnosis of pulmonary embolism, the question can be answered with some certainty, but not unequivocally, because published studies of efficacy of lung scan are few. If the lung scan is being considered as an aid in diagnosis of a patient with pulmonary disease other than pulmonary embolism, the information being sought must be well defined, since such diseases produce generalized abnormalities of both perfusion and ventilation, and scanning studies do not result in specific diagnoses. Such disclaimers, however, do not negate the value of the technique of lung scanning; they merely advise circumspection in its use.
Diagnosis and Prevention
It is not the purpose of this article to discuss the therapy for thromboembolic disease, but the stage must be set
Shoop JD. Why Do a Lung Scan?. JAMA. 1974;229(5):567-570. doi:10.1001/jama.1974.03230430059033