The authors demonstrated the use of mixture distribution analysis as an alternative to receiver operating characteristic (ROC) analysis in a clinical study, where independent verification of the imaging diagnosis is not always feasible. ROC and mixture distribution analyses were applied to the blind readings of four radiologists on a stratified, random sample of 95 screen-film radiographs and 95 computed radiographs of the chest obtained from a medical intensive care unit. The imaging diagnosis established by an expert panel was used as the truth for the ROC analysis, and agreement of ratings was used for the mixture distribution analysis. Both methods yielded similar values for the proportion of correct diagnoses. Mixture distribution analysis may be useful for comparing imaging techniques in situations where the true imaging diagnosis cannot be established with a method independent of that being evaluated.