Figure 11. Maps of (a) K^trans and (b) k_fp on a patient with a glioblastoma multiforme. Note the standard conventional 2-compartment model (a) shows apparent areas of extremely high permeability in the region of feeding and draining blood vessels. Small blood vessels throughout the brain also appear as areas of high permeability. In the modified model (b), contributions from intravascular contrast are explicity modelled. This image of k_fp is therefore free of these pseudopermeability effects. Elevated areas of k_fp can be seen within the tumour and in the choroid plexus and peripineal organs where the blood–brian barrier is not intact.