DOES INTENSITY WINDOWING IMPROVE THE DETECTION OF SIMULATED CALCIFICATIONS IN DENSE MAMMOGRAMS

This study attempts to determine whether intensity windowing (IW) impr oves detection of simulated calcifications in dense mammograms. Cluste rs of five simulated calcifications were embedded in dense mammograms digitized at 50-mu m pixels, 12 bits deep. Film images with no windowi ng applied were compared with film images with nine different window w idths and levels applied. A simulated cluster was embedded in a realis tic background of dense breast tissue, with the position of the cluste r varied. The key variables involved in each trial included the positi on of the cluster, contrast level of the cluster, and the IW settings applied to the image. Combining the ten IW conditions, four contrast l evels and four quadrant positions gave 160 combinations. The trials we re constructed by pairing 160 combinations of key variables with 160 b ackgrounds. The entire experiment consisted of 800 trials. Twenty stud ent observers were asked to detect the quadrant of the image in which the mass was located. There was a statistically significant improvemen t in detection performance for clusters of calcifications when the win dow width was set at 1024 with a level of 3328, and when the window wi dth was set at 1024 with a level of 3456. The selected IW settings sho uld be tested in the clinic with digital mammograms to determine wheth er calcification detection performance can be improved. Copyright (C) 1997 by W.B. Saunders Company.