Pulmonary scintigrams were analyzed in conjunction with matched pulmonary angiograms for perfusion patterns, relation of perfusion to ventilation, and changes, with time, in the perfusion pattern. Eighty percent of the patients with lobar defects seen on scan and 30% with segmental or subsegmental defects had angiographic evidence of pulmonary embolism.
Patients with lobar defects and pulmonary embolism had a lower incidence of findings on chest roentgenograms than did the other groups. Of the 20 patients with mismatched abnormalities of perfusion and ventilation, 19 had pulmonary emboli; none of the five patients with matched perfusion and ventilation had emboli.
A rapidly changing perfusion pattern was found in ten patients with acute pulmonary embolism while a fixed pattern was found in five patients who did not have emboli. The data indicate that a large perfusion defect and a ventilation-perfusion mismatch correlate strongly with pulmonary embolism.
McNeil BJ, Holman BL, Adelstein SJ. The Scintigraphic Definition of Pulmonary Embolism. JAMA. 1974;227(7):753–756. doi:10.1001/jama.1974.03230200011002
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