Evaluation of observer performance in detecting blood vessels on simulated angiographic images

This paper presents methods for evaluating the effects of technical factors on observers' detection of small blood vessels in angiographic images. A fixed set of physical parameters was used to generate computer-simulated angiographs that contained blood vessels of various diameters. Observers' judgments about each set of images permitted estimation of the receiver operating characteristic (ROC) curves for vessel detection and of the probability of correctly locating the vessels. Both parametric and nonparametric methods were used to characterize the ROC curves. Three different, but theoretically related, measures of vessel detectability varied systematically with changes in the blood vessel's diameter, reflecting changes in observer performance.