Comparative study of methods for determining vascular permeability and blood volume in human gliomas

Purpose To characterize human gliomas using T 1 ‐weighted dynamic contrast‐enhanced MRI (DCE‐MRI), and directly compare three pharmacokinetic analysis techniques: a conventional established technique and two novel techniques that aim to reduce erroneous overestimation of the volume transfer constant between plasma and the extravascular extracellular space (EES) ( K trans ) in areas of high blood volume. Materials and Methods Eighteen patients with high‐grade gliomas underwent DCE‐MRI. Three kinetic models were applied to estimate K trans and fractional blood plasma volume ( v p ). We applied the Tofts and Kermode (TK) model without arterial input function (AIF) estimation, the TK model modified to include v p and AIF estimation (mTK), and a “first pass” variant of the TK model (FP). Results K TK values were considerably higher than K mTK and K FP values ( P < 0.001). K mTK and K FP were more comparable and closely correlated (ρ = 0.744), with K mTK generally higher than K FP ( P < 0.001). Estimates of v p ( mTK ) and v p ( FP ) also showed a significant difference ( P < 0.001); however, these values were very closely correlated (ρ = 0.901). K TK parameter maps showed “pseudopermeability” effects displaying numerous vessels. These were not visualized on K mTK and K FP maps but appeared on the corresponding v p maps, indicating a failure of the TK model in commonly occurring vascular regions. Conclusion Both of the methods that incorporate a measured AIF and an estimate of v p provide similar pathophysiological information and avoid erroneous overestimation of K trans in areas of significant vessel density, and thus allow a more accurate estimation of endothelial permeability. J. Magn. Reson. Imaging 2004;20:748–757. © 2004 Wiley‐Liss, Inc.