An improved computer-assisted diagnostic scheme using wavelet transform for detecting clustered microcalcifications in digital mammograms

Rationale and Objectives. We evaluated the potential usefulness of a computer-assisted diagnostic (CAD) scheme incorporating the wavelet transform for detecting clustered microcalcifications in mammograms. Methods. A wavelet transform technique was applied to the detection of clustered microcalcifications, We examined several wavelets to study their effectiveness in detecting subtle microcalcifications. We used a database consisting of 39 mammograms containing 41 clusters of microcalcifications. The performance of the wavelet-based CAD scheme was evaluated using free-response receiver operating characteristic analysis. Results. The CAD scheme with the wavelet transform was useful in detecting some of the subtle microcalcifications that were not detected by our previous scheme, which was based on the difference-image technique. When the two schemes were combined, the overall performance was improved to a sensitivity of approximately 95%,with a false-positive rate of 1.5 clusters per image. Conclusion. The wavelet transform approach can improve the detection of subtle clustered microcalcifications.