Image quality of digital direct flat-panel mammography versus an analog screen-film technique using a low-contrast phantom.

Objective: The objective of our study was to compare the detectability and distinguishability of simulated soft-tissue opacities of 50 variants of an anthropomorphic breast phantom in mammograms acquired with a digital direct flat-panel detector versus an analog system; we also compared the image settings "analog film," "digital film," and "digital monitor."

Materials And Methods: The studies were performed on digital (Lorad Selenia) and analog (Mammomat 3) mammography systems. Four hundred fifty silicone cubes devised with different randomly distributed columns, holes, or both columns and holes (diameter, 3-7 mm; height, 0.5-4.0 mm) were used as test bodies. One experimental series was performed with a silicone scatter body and one with a silicone and an anthropomorphic ground-meat scatter body. All x-rays were obtained at identical settings and exposures. Four radiologists rated the films and monitor-displayed images independently of each other in randomized order on a standardized electronic questionnaire.

Results: The digital monitor technique generally scored better than digital film viewing and analog readings. The McNemar test for multiple paired comparisons mostly yielded a p value of < 0.0005. The smallest volume category counted as the most valid test scenario for all raters, where the percentage of correct positive findings ranged between 30% and 58% (analog technique), 43% and 68% (digital film viewing), and 55% and 66% (monitor viewing). The corresponding accuracy rates were 77-93%, 75-95%, and 81-85%, respectively, with kappa values of 0.2-0.5 (analog) and 0.3-0.6 (digital) for comparing the gold standard with raters' evaluations.

Conclusion: Digital flat-panel mammography is superior to the analog screen-film method for the detection of simulated opacities.