MIXTURE DISTRIBUTION AND RECEIVER OPERATING CHARACTERISTIC ANALYSIS OF BEDSIDE CHEST IMAGING WITH SCREEN-FILM AND COMPUTED RADIOGRAPHY

Rationale and Objectives. The authors demonstrated the use of mixture distribution analysis as an alternative to receiver operating characte ristic (ROC) analysis in a clinical study, where independent verificat ion of the imaging diagnosis is not always feasible. Methods. ROC and mixture distribution analyses were applied to the blind readings of fo ur radiologists on a stratified, random sample of 95 screen-film radio graphs and 95 computed radiographs of the chest obtained from a medica l intensive care unit. The imaging diagnosis established by an expert panel was used as the truth for the ROC analysis, and agreement of rat ings was used for the mixture distribution analysis. Results. Both met hods yielded similar values for the proportion of correct diagnoses. C onclusion. Mixture distribution analysis may be useful for comparing i maging techniques in situations where the true imaging diagnosis canno t be established with a method independent of that being evaluated.