Vascular permeability: quantitative measurement with double-echo dynamic MR imaging--theory and clinical application.

Double-echo dynamic magnetic resonance (MR) imaging was used to evaluate both vascularity and permeability of tissues simultaneously. Vascularity was evaluated on the basis of the T2*-shortening effect due to the intravascular fraction of the contrast agent and permeability on the basis of the T1-shortening effect due to the extravascular fraction. Meningioma was characterized on the basis of higher vascularity and neurinoma on the basis of higher permeability. The proposed method enables better tissue characterization.