Long-term in vivo imaging of amyloid plaque growth kinetics in Tg2576 mouse model of AD. (a) A young and an old cohort were investigated from 12 to 14 and 18 to 20 months of age, respectively, at a weekly imaging intervals. (b) Time series of 3D volume-rendered images acquired with two-photon fluorescence microscopy showing amyloid plaques and cerebral amyloid angiopathy (CAA). The length of one side of the squares equals 100 μm. (c) Mean volumes of all plaques over time (open circles). The black line indicates a fitted sigmoid function (R2 0.983). Error bars show the 95% confidence intervals (CI). (d) Integrated volume of all plaques over time (open circles). The black line indicates a fitted sigmoid function (R2 0.988). In addition, the temporal development of the plaque density is depicted (gray line) which can be fitted to an exponential function of one phase association (R2 0.975). (e) Integrated volume of the cerebral amyloid angiopathy (open circles) with the corresponding fit of a sigmoid function (R2 0.952).