We describe a new method to allow simultaneous mapping of endothelial permeability and blood volume in intracranial lesions. The technique is based on a tumor leakage profile during the first pass (fp) of contrast bolus calculated from the time-dependent plasma-contrast concentration function (PCCF) in three-dimensional (3D) T1-weighted dynamic studies. The performance of the method has been evaluated by comparing results with those obtained from more conventional methods in patients with primary brain neoplasms. The new permeability maps (k(fp)) are visually compatible with those calculated using a conventional multicompartment model (k(tran)). Quantitatively, the new maps are free from overestimation of k(tran) due to first-pass effects. The new blood volume maps, which segment out the contamination of contrast leakage, agree closely with maps derived from susceptibility studies. The new method is fast, robust, and easy to perform. The method is suitable for use in clinical environments and is likely to be of benefit where longitudinal assessment of treatment response is required.