MRI Based Response Assessment and Diagnostics in Glioma

Gliomas are primary brain tumors in adults and are categorized by the World Health Organization (WHO) as grade I and II (low-grade gliomas), grade III (anaplastic) and IV (glioblastoma). Glioblastoma encompass 15% of all brain and central nervous system tumors and almost half of all primary brain tumors. Astrocytoma and glioblastoma are categorized by the mutational status of the gene encoding for isocitrate dehydrogenase (IDH): IDH-mutant (IDHmt) and IDH wild-type (IDHwt). By definition, oligodendroglioma is both 1p19q codeleted and IDHmt. While the exact diagnosis and tumor grade is determined by assessment of molecular markers and histology, Magnetic Resonance Imaging (MRI) can give information on the diagnosis as well. General features that can help predict glioma grade are presence or lack of contrast-enhancement and necrosis. More advanced measures such as Apparent Diffusion Coefficient (ADC) derived from Diffusion Weighted Imaging (DWI) and regional cerebral blood volume (rCBV) from perfusion imaging can also have added value and are therefore often included in clinical glioma scanning protocols