ROC analysis comparing screen film mammography and digital mammography

Purpose: To compare the diagnosis performances of radiologists on screen fi lm versus digital mammography. Material and methods: Two sets of 123 mammograms, screen film mammography a nd storage phosphor digital mammography, are studied comparatively with ROC analysis. Results: Phantom study show that conventional method give better scores for usual tension but the detectability of smaller microcalcification is equiv alent. To obtain with digital technic the same conventional score you have to increase the radiation dose. Roc Curves, simulated "detection" mode show ed that radiologists performed with higher accurancy with concentional syst em but this difference is weekly statistically significant. ROC Curves, sim ulated "diagnostic" mode showed the same results wit no statistically signi ficant difference but when the decision to go to the biopsie is the gold st andard. ROC Curves were ssentially equivalent for both film screen and digi tal mammography system. The readers consistently considered the digital mam mograms to be less suspicious for cancer findings. The agrement study as pr oposed by the FDA indicate that probability of a positive digital mammogram s given a positive screen film is 75% (threshold value 90%) and the probabi lity of a negative digital mammograms given a negative analog film is 85% ( threshold value 85%). Conclusion: Analysis of specific discrepanciers indic ate that spatial resolution is an essential limitant factor for digital met hod but high resolution phosphor plate are interesting in imaging treated b reast, radioluscent lesion, fatty benign tumor, hamartoma, intramammary lym ph node, breast with prosthesis.