ABSTRACT
Perfusion MR imaging (MRI) is currently an evolving technology that has become a popular alternative to ionizing radiation techniques, such as nuclear medicine and computed tomography based perfusion, for the study of cerebral hemodynamics and blood flow. These techniques have been inspirational regarding brain perfusion, but are now mainly limited by the absorbed radiation dose restrictions, especially concerning repeated exams, as well as the low spatial resolution compared to MRI. "Perfusion" is defined as the steady-state delivery of blood to an element of tissue, such as the capillary blood flow. Perfusion MRI techniques can be classified according to the contrast mechanism used, into exogenous and endogenous. Although a number of limitations in the different endogenous or exogenous contrast perfusion methods remain, the acquired parameters are of great importance and the inclusion of perfusion MRI in the clinical routine is expected to improve diagnostic accuracy and understanding of tumor pathophysiology.
