Reduced-dose CT: effect on reader evaluation in detection of pulmonary embolism.

Objective: The purpose of this study was to evaluate the effect of reduction in radiation dose on CT detection of pulmonary embolism.

Subjects And Methods: Emergency department patients were evaluated for pulmonary embolism with standard and simulated reduced-dose CT angiography. Simulated lower-dose CT angiograms obtained at 90, 45, 22, and 10 mAs(eff) were reconstructed by mathematical addition of noise to the standard dose (180 mAs(eff)) data from the images of 18 patients with and 20 patients without pulmonary embolism.