Performance in digital mammography with and without film prior mammograms
KeywordsScreening Programme Screen Programme Recall Rate Digital Mammography Breast Screening
In the transition to digital mammography the prior mammograms are in film format. There are difficulties making comparisons between digital current and film prior mammograms due to differences in image appearance and display brightness. This study investigates cancer detection performance in digital mammography with and without film prior mammograms.
Two radiologists and two radiography advanced practitioners read a set of 160 (41% malignant) difficult digital mammography cases twice, once with film prior mammograms and once without. Participants noted whether they would recall each case in the NHS breast screening programme.
The number of false negative cases (that is, missed cancers) did not differ between conditions. There was a trend towards a larger number of false positive cases (that is, normal cases that were recalled) when prior mammograms were not available (24% increase, P = 0.058). If this trend continued throughout the NHS Breast Screening Programme, then discarding prior mammograms would correspond to an increase in recall rate from 4.6% to 5.3%, and 12,414 extra women recalled annually for assessment.
Initial results indicate that film prior mammograms may be beneficial to cancer detection performance in digital mammography, and therefore should be displayed. Completion of the study with four extra participants will allow firmer conclusions to be drawn.
This article is published under license to BioMed Central Ltd.