Fig. 1

a–d Scatter plots of ipsilateral vs. contralateral changes for cases, or matched side for controls, in volumetric percent density (VPD) (a), dense volume (DV) (b), by tumor size in cases only VPD (c) and DV (d). Ipsilateral change is on the x-axis, and contralateral change is on the y-axis. The 45° line represents equal changes in both breasts. Subjects with a smaller decrease in density of the ipsilateral breast relative to contralateral are below the 45° line. *Correlation coefficients: a cases VPD = 0.57 (0.43, 0.61), controls VPD = 0.72 (0.70, 0.75); b cases DV = 0.48 (0.44, 0.53), DV controls = 0.62 (0.59, 0.65); c cases VPD <= 2 cm = 0.61 (0.56, 0.65), 2–5 cm = 0.50 (0.40, 0.58), and > 5 cm = 0.51 (0.31, 0.67); d cases DV <= 2 cm = 0.52 (0.46, 0.56), 2–5 cm = 0.48 (0.39, 0.57), and > 5 cm = 0.15 (0.01, 0.30)