Digital subtraction radiography was used in 84 patients with suspected pulmonary embolism to obtain information about localized changes in ventilation of the lungs. Preliminary experiences in patients with carcinoma of the lung, emphysema and acute inflammatory diseases have also been obtained. Digital subtraction radiography is a simple, rapid and inexpensive method to obtain information about ventilation in the lungs. It is completely non-invasive and requires only minimal cooperation of the patient. The sensitivity appears to be as good as that of 133Xe radionuclide ventilation studies.
