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Abstract
MR imaging is now a well established tool for evaluation of brain tumors but conventional MR technique continues to have important limitations. These limitations include inability to reliably distinguish exact limits of tumor extension and discriminate between recurrent tumor and radiation necrosis (Wong et al., 2000).
As novel therapies for patients with brain tumors are being developed the role of imaging has begun to shift to provide information on tumor physiology, as well as anatomy. Perfusion methods are ideally suited to such physiological imaging (Covarrubias et al.,2004).
MR perfusion imaging refers to several recently developed techniques used to non invasively measure Cerebral perfusion via assessment of various hemodynamic measurements such as cerebral blood volume, cerebral blood flow and mean transit time (Petrella and Provenzale, 2000).
Multiple studies have shown that perfusion MR techniques can non invasively estimate tumor grade preoperatively. This can in turn help guide stereotactic biopsy by directing the surgeon to the most aggressive portions of the tumor. MR perfusion also holds promise in providing, better delineation of tumor margins than conventional techniques which can similarly assist in surgical and radiation planning. MR perfusion is also useful in the follow up of brain tumor by allowing differentiation between radiation effects and recurrent tumor. Perfusion changes also hold promise as surrogate markers of response to therapy in clinical trials of newer antiangiogenic pharmaceuticals (Covarrubias et al.,2004).
The aim of this work is to demonstrate the value of perfusion weighted magnetic resonance as an emerging technique for imaging of brain tumors.