Reproducibility of Computer-Aided Detection Marks in Digital Mammography
Seung Ja Kim, Woo Kyung Moon, Nariya Cho, Joo Hee Cha, Sun Mi Kim, Jung-Gi Im · Korean Journal of Radiology · 2007
Objective: To evaluate the performance and reproducibility of a computeraided detection (CAD) system in mediolateral oblique (MLO) digital mammograms taken serially, without release of breast compression.Materials and Methods: A CAD system was applied preoperatively to the fullfield digital mammograms of two MLO views taken without release of breast compression in 82 patients (age range: 33 83 years; mean age: 49 years) with previously diagnosed breast cancers.The total number of visible lesion components in 82 patients was 101: 66 masses and 35 microcalcifications.We analyzed the sensitivity and reproducibility of the CAD marks.Results: The sensitivity of the CAD system for first MLO views was 71% (47/66) for masses and 80% (28/35) for microcalcifications.The sensitivity of the CAD system for second MLO views was 68% (45/66) for masses and 17% (6/35) for microcalcifications.In 84 ipsilateral serial MLO image sets (two patients had bilateral cancers), identical images, regardless of the existence of CAD marks, were obtained for 35% (29/84) and identical images with CAD marks were obtained for 29% (23/78).Identical images, regardless of the existence of CAD marks, for contralateral MLO images were 65% (52/80) and identical images with CAD marks were obtained for 28% (11/39).The reproducibility of CAD marks for the true positive masses in serial MLO views was 84% (42/50) and that for the true positive microcalcifications was 0% (0/34).Conclusion: The CAD system in digital mammograms showed a high sensitivity for detecting masses and microcalcifications.However, reproducibility of microcalcification marks was very low in MLO views taken serially without release of breast compression.Minute positional change and patient movement can alter the images and result in a significant effect on the algorithm utilized by the CAD for detecting microcalcifications.computer-aided detection (CAD) system can assist the radiologist in the early detection of breast cancer by highlighting suspicious areas seen on mammography (1, 2).Reproducibility is one of the important factors for determining the quality of a CAD system.Recent CAD studies involving repeated scanning of film mammograms of breast cancer patients showed 39 53% reproducibility, markedly decreased from the 95 99% claimed by the manufacturers of the CAD systems (3, 4).It is likely that variability of marks is primarily caused by small shifts in the film position between sequential digitizations (5).Recently, the CAD system has been applied to full-field digital mammography and results for breast cancer detection were reported to be similar to those obtained using an analog system (6).When CAD is used with full-field digital mammography, it