Interpretation of calcifications in screen film, digitized, and wavelet-enhanced monitor-displayed mammograms: A receiver operating characteristic study

Rationale and Objectives. The acceptance of filmless digital mammography is currently limited by digitization and display drawbacks, as well as bias coward hard-copy interpretation In the current study, we evaluated a wavelet-based image enhancement method for the filmless interpretation of breast calcifications. Methods. A set of 100 mammograms (58 with calcification clusters) was digitized at 105 mu m and 4,096 gray levels per pixel and was processed with nonlinear filters and wavelets. Standard receiver operating characteristic analysis was performed by four radiologists, who independently read the films, the unprocessed digital images, and unprocessed and wavelet-enhanced digital images presented simultaneously. Results. Statistical differences were observed between screen/film and unprocessed digitized mammography displayed on monitors. Differences were not significant when wavelet enhancement was included in the monitor display. Interobserver variation in the digitized reading was greater than in film reading, but the wavelet enhancement reduced the difference. Conclusion. Wavelet-enhanced digital mammograms may assist radiologists in diagnosing calcifications directly from computer monitors and may compensate for current technologic limitations. A study with a larger database is needed before this method is accepted for clinical use.