Brain tumors represent a vast group of lesions, originating from different neuronal cells with different degrees of aggressiveness. Despite some technological advances either pre or post-treatment, these tumors may share similar imaging findings and properties, rendering diagnosis/prognosis, an ambiguous process. Gadolinium-enhanced magnetic resonance imaging remains the gold standard for providing detailed morphologic information, but presents several limitations due to the overlap of findings, in cases such as progressive tumor and post-radiation related effects. Tumor cellularity, vascularity, proliferative activity, metabolic and functional profiles are a few of many characteristics that may further support tumor classification, but cannot be assessed by conventional imaging alone. We review the aforementioned factors and indicate how they improve tumor characterization and grading in order to design the optimal treatment strategy and better evaluate post treatment efficacy.