Comparison of real and computer-simulated clustered microcalcifications on digital mammograms. ROC study

The authors propose a model to simulate clustered microcalcifications on digital mammograms. The simulation model is based on the gray-level, size and number of microcalcifications per cluster. All the parameters describing the individual microcalcifications and clusters were randomly sampled from the values of the real clustered microcalcifications (extracted in a feature analysis process) present in the mammogram, the exception being the center of the cluster, that was interactively positioned to ensure the location of all the microcalcifications inside the breast. Subsequently, a database of clustered microcalcifications was created. These clusters of microcalcifications from this database were tested from indistinguishability from real ones. Two radiologists and one physicist were asked to indicate wether the microcalcifications were either real or simulated. The responses of the readers were evaluated with an ROC analysis, and the area under the curve was calculated. The average ROC area was 0.54/spl plusmn/0.05, indicating that there was no statistical difference between real and simulated clustered microcalcifications.