Relative accuracy of two diagnostic schemes for detection of pulmonary embolism by ventilation-perfusion scintigraphy.

Abstract

Two diagnostic schemes for detection of pulmonary embolism by ventilation-perfusion (V-P) scintigraphy were compared for relative accuracy by 2 groups of observers interpreting 70 V-P scintiscans. Observers in Group B, who used criteria recently proposed had a significantly smaller average number of indeterminate interpretations (41%) than did the observers in Group A (55%), who used a simpler scheme (P < 0.05). In addition, Group B showed a slight improvement in positive predictive value without a deterioration in the negative predictive value compared with Group A. Along with this improvement in diagnostic performance, Group B achieved a significant reduction in interobserver variability compared with Group A for patients without pulmonary embolism (P < 0.05). There was no significant difference in interobserver variability between the 2 groups for patients with pulmonary embolism. The diagnostic scheme introduced represents a useful improvement for the diagnosis of pulmonary embolism by V-P imaging.