Influence of monitor characteristics on the signals detection present in the mammographic phantom image - art. no. 69171H

Abstract

The objective of this study was to compare the detection of microcalcifications and fibers on phantom images based on monitor readings versus analog image readings. 180 films were obtained with 3 different mammographic equipment under different exposure conditions and digitized using the Lumiscan75 scanner. It was used the ALVIM statistical phantom (4,5cm) and 2 acrylic plates of 1cm (6,5cm) over it. the software named QuallM was developed to manager the images and the database which storages the specialist's readings allowing them digital tools manipulation. the images were displayed on 4 monitors: CRT Philips 19 (2,9Mpixels/8bits), CRT Philips 22 (3,0Mpixels/8bits), LCD Clinton (3,0Mpixels/10bits) and LCD Barco (5,5,0Mpixels/14bits). the same images group wets also displayed on the appropriated view box to mammograms (3200cd/m(2)) and the readings performance was taken as reference parameter. the software generates on real time Kappa values to microcalcifications and fibers detection, histogram, ROC curve and true/false positive parameters. Barco monitor readings produced superior results when compared with all the others suggesting that there weren't losses in the digitalizing process. Clinton monitor readings were similar the view box results and superior on both Philips monitors when compared the detection of objects on phantom images (6,5cm). the specialist performance results using Philips 22 were only comparable to view box and Clinton for images of 4,5cm. It was possible to verify that the monitors' spatial and contrast resolutions have influenced on the readings performance of specialists, suggesting these characteristics are relevant at lesions detection performance in mammographic exams.