Quantitative characterization of hemodynamic properties and vasculature dysfunction of high‐grade gliomas

Abstract

Aberrations in tumor and peritumoral vasculature may not be distinguishable by cerebral blood flow (CBF) or cerebral blood volume (CBV) alone. The relationships between CBF and CBV were examined to estimate vasculature‐specific hemodynamic characteristics. Twenty glioma patients were studied with dynamic susceptibility T₂*‐weighted MRI [(dynamic contrast‐enhanced magnetic resonance imaging (DSC‐MRI)] before and during week 1 and 3 of radiotherapy (RT). CBF and CBV were calculated from DSC‐MRI, and relationships between the two were evaluated: the physiological measure of mean transit time (MTT) = CBV/CBF; empirical fitting using the power law CBV = constant × (CBF)^β. Three different tissue types were assessed: the Gd‐enhancing tumor volume (GEV); non‐enhanced abnormal tissue located beyond GEV but within the abnormal hyperintense region on FLAIR images (NEV); normal tissue in the hemisphere contralateral to the tumor (CNT). The effects of tissue types, CBV magnitudes (low, medium and high), before and during RT, on MTT and β were analyzed by analysis of variance (ANOVA). The MTT and β for the three tissue types were significantly different (p < 0.009). MTT increased from CNT (1.60 s) to NEV (1.93 s) to GEV (2.28 s) (p < 0.0005). β was significantly greater in GEV (1.079) and NEV (1.070) than in CNT (1.025). β increased with increasing CBV magnitude while MTT was independent of CBV magnitude. There was a significant decrease in MTT of NEV and GEV during week 3 of RT compared with pre‐RT values for all CBV magnitudes. There was a significant increase in β during RT in the tumor and peritumor. Progressive abnormalities in vasculature and hemodynamic characteristics of the vascular bed were delineated, with significant disorder in the tumor but mild abnormality in peritumoral tissue. Copyright © 2007 John Wiley & Sons, Ltd.