Glioma is the most common type of primary tumors in the brain,histologically varying from low grade to high grade.Physiological regional heterogeneity also has been well documented in glioma.Hypercellularity,pleomorphism,vascular endothelial proliferation,mitotic activity,and necrosis are important histopathological characteristics,which determine tumor grading and its malignancy.Advanced MR imaging currently provides in vivo physiological and metabolic information including chemical composition,cerebral blood volume,perfusion,vascular permeability,and water mobility,which reflect those pathophysiological features of brain glioma to some extent.To date,MR spectroscopy,diffusion weighted imaging,perfusion weighted imaging and other new MRI techniques have many advantages on tumor grading,monitoring malignant transformation,predicting prognosis,and differentiating between tumor recurrence and malignant progression.
