A comparative study of intravenous digital subtraction angiography and ventilation-perfusion scans in suspected pulmonary embolism.

We observed 102 patients suspected of having pulmonary emboli (PE) who underwent ventilation-perfusion (V/Q) lung scintigraphy and IV digital subtraction angiography (DSA). Only five DSA studies were inadequate for interpretation. In 81 of the remaining 97 patients (83.5 percent) the results of both studies correlated regarding the probability of PE. In 50 patients the results of both studies were highly suggestive of PE; in 31 patients DSA and V/Q were normal or classified as low probability of PE. There was disagreement in 3/97; in 13/97 one or both studies were nondiagnostic. The clinical data of these 16 patients are given. Conventional catheter pulmonary angiography was indicated in 11/102 patients to establish a firm diagnosis of PE. The results of V/Q and DSA correlated in 83 percent (49/59) of patients without chronic obstructive pulmonary disease (COPD) and in 84 percent (32/38) of the patients with COPD.