Figure 1.

Study design overview. The arrow at A represents the date at which a facility introduced digital mammography. Mammograms performed at this facility were then classified according to the one year period relative to this date during which they were performed. For instance, the mammogram at B represents a screening examination performed in the period two years after the introduction of digital mammography. For this mammogram, utilization was then evaluated in the one year interval before and one year interval after the mammogram was performed.