The aim of this prospective study was to characterize intracranial tumors on the basis of the degree of blood-brain-barrier (BBB) disruption and tumor blood flow (TBF). We studied 28 patients with brain tumors by MRI. BBB disruption was demonstrated by a pathological increase of signal intensity in T1-weighted spin-echo images (1.5 T, TR = 600 ms, TE = 10 ms, alpha = 90 degrees) after intravenous gadolinium-DTPA injection. TBF flow was assessed by an MRI-method based on the signal intensity decrease in T2-weighted gradient-echo images (TR = 25 ms, TE = 20 ms, alpha = 10 degrees) immediately after gadolinium-DTPA bolus injection. Typical constellations include intake BBB and low TBF in low-grade intraaxial tumors (astrocytoma I/II), disrupted BBB and heterogeneous TBF in high-grade intraaxial tumors (glioblastomas and metastases), and disrupted BBB and high TBF in extraaxial tumors (meningeomas). This study demonstrates the quasi-simultaneous assessment of the blood-brain-barrier and tumor blood flow. The results support the concept that additional uncorrelated information is obtained from the assessment of regional cerebral blood flow that may be helpful for the differential diagnosis of brain tumors.