Evaluation of a multiscale enhancement protocol for digital mammography

Wehave,carried out a receiver ,operating characteristics (ROC) study for the enhancement ,of mammographic ,features in digitized mammograms. ,The study evaluated the ,benefits of multi-scale enhancement methods ,in terms ,of diagnostic performance,of radiologists. The ,enhancement ,protocol relied on multi-scale ,expansions ,and non-linear enhancement functions. Dyadic spline wavelet functions (first derivative of a cubic spline) were used together with a sigmoidal non-linear enhancement function [1], [2]. We designed a computer interface on a softcopy display and performed an ROC study with three radiologists, who specialized in mammography. Clinical cases were obtained from a national mammography database of digitized radiographs prepared by the University of South Florida (USF) and Harvard Medical School. Our study focused on dense mammograms, i.e. mammograms of density 3 and 4 on the American College of Radiology (ACR) breast density rating, which are the most difficult cases in screening, were selected. To compare the performance of radiologists with and without using multi-scale enhancement, two groups of 30 cases each were diagnosed. Each group contained 15 cases of cancerous and 15 cases of normal mammograms. Conventional ROC analysis was applied, and the resulting ROC curves ,indicated ,improved ,diagnostic performance ,when ,radiologists used ,multi-scale non-linear enhancement. Keywords: Multi-scale analysis, ROC analysis, contrast enhancement, digital mammography, softcopy display.