Pharmacokinetic analysis of DCE-MRI curves. (A, C) Average signal versus time
curves (normalized to the pre-contrast series) from pixels of predominantly blue (necrotic), green
(hypoxic), and red (perfused) areas from tumors B (744 mm3) and D (1230 mm3).
(B, D) Corresponding histograms of Akep values in the three types of
tissues as identified by unsupervised PR analysis of DCE-MRI data. Note that in these types of
quantification the tumor areas that show no contrast uptake, as well as pixels falling outside of
the highest quartile for well-perfused, hypoxic, or necrotic weights W, respectively,
were excluded.