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Figure 1. Quantitative assessment of breast density with a computerized thresholding method (35). The computer interface is demonstrated. With this technique, the digitized mammogram is displayed. The red line marks the skin edge and is controlled by the bar labeled "Edge Threshold" in the threshold panel. The green line marks the breast parenchyma and is controlled by the bar labeled "Density Threshold." The user can move either bar to select the appropriate skin line and the area of breast tissue. The user draws a line to denote the boundary of the pectoralis muscle and that area is excluded. Two other masks can be used to exclude markers, et cetera. The total, dense area, and percentage of density are then calculated. In this example, the breast is 26.5% dense. (Image courtesy of Martin Yaffe, University of Toronto).
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