P.M. Parizel et al. Characterization of brain tumors - 1 - Characterization of brain tumors P. M. Parizel 1 , J. Van Goethem 1 , L. van den Hauwe 1 , R. Salgado 1 , E. Vandervliet 1 , A. Leemans 2 1 Department of Radiology Universitair Ziekenhuis Antwerpen University of Antwerp, Belgium 2 Vision Laboratory Department of Physics University of Antwerp, Belgium Neuroradiology plays an essential part in the clinical management of patients with brain tumors [1]. Magnetic resonance imaging (MRI) and, to a lesser extent, computed tomography (CT) are the cornerstones for the diagnosis, definition of extent, detection of spread and follow-up of residual or recurrent tumor [2]. The purpose of this presentation is to discuss basic and advanced neuroradiological techniques that have been developed in the examination and management of patients with brain tumors. Until recently, neuroradiological techniques were used to characterize cerebral neoplasms by: • Definition of the exact tumor location (intra- or extra-axial, supra- or infratentorial) [3,4,5]; • Demonstration of anatomy in various planes; • Display of differences in tissue density (MDCT); • Display of differences in MRI signal intensity between normal and abnormal brain tissue; • Use of contrast media to demonstrate tumor vascularity (cerebral arteriography) or to detect breakdown of the blood brain barrier. Recent technological advances have opened new windows in our ability to detect and characterize tumors [6]. These new advances include rapid/ultrafast imaging, metabolic and functional imaging. Metabolic imaging aims to identify molecular biological factors that are potentially able to guide clinical management decisions; these techniques include MR spectroscopy and cerebral perfusion mapping. Functional MRI concerns the changes in cerebral hemodynamics that accompany brain function (activation); this latter topic lies outside the scope of this paper.