Role of Susceptibility Weighted Imaging (SWI) in Assessment of Intra Axial Brain Neoplasms in Adults

Abstract

everal magnetic resonance (MR) imaging methods have been introduced for the evaluation of brain gliomas. It is important to grade the tumors prior to therapeutic intervention because prognosis and appropriate therapy vary according to tumor grade. Among the viable imaging techniques, SWI is MR imaging technique that provides more information on venous vasculature, hemorrhage and iron deposition within the brain. Therefore the value of SWI in detecting ITSS which result from neovascularity, intralesional bleeding and necrosis and using this information to grade gliomas has been researched intensely. This method was based on the theory that intratumoral hemorrhage and microvascularity correlate with histopathologic tumor grade. We investigated several methods for assessment of ITSS and found that all of them could accurately differentiate HGGs from LGGs, but failed to distinguish WHO grade III and WHO grade IV tumors, except for the number of ITSS, which was the only parameter that could differentiate WHO grades II,III, and IV tumors, making it the best method for grading of gliomas on SWI. Occasional false results can, however, result from oligodendrogliomas which may show dense ITSS despite being WHO grade II lesions, and from infrequent cases of HGGs which fail to demonstrate ITSS.