Pulmonary embolic disease: the roles of angiography and lung scanning in diagnosis.

The definitive diagnosis of pulmonary embolism remains difficult despite recent advances in nuclear medicine and angiography. In 10% of a selected series of 145 patients a negative chest x-ray and a positive lung scan was associated with no arteriographic evidence of pulmonary emboli. A normal perfusion lung scan excludes significant pulmonary embolism. When pulmonary arteriography is necessary, a biplane selective pulmonary angiogram should be performed and subselective injections may be required. Pulmonary arteriography is less of a threat to a patient suspected of having pulmonary embolic disease than inappropriate treatment.