MKI67 and glioma: Further quantitative analysis of high-grade glioma heterogeneity using the entropy metric revealed considerably higher intratumoral heterogeneity for Ki67+ maps predicted by kio (1.11 ± 0.31) than for those predicted by standard MRIs (0.05 ± 0.01, p = 0.009, n = 27) and other water-exchange DCE-MRI-derived pharmacokinetic metrics (0.05 ± 0.01, p = 0.009, n = 27).