Fig. 1.
Biophysical features characterized by conventional and advanced physiologic MRI techniques. Shown are 6 MRI techniques that are commonly employed in neuro-oncologic imaging, along with their respective corresponding tumor phenotypes. T2-weighted (T2W) signal is typically used to define vasogenic edema. T1-weighted post-contrast enhancement (T1 + C) shows areas of disrupted blood-brain barrier (BBB). Dynamic susceptibility contrast (DSC) MRI measures of relative cerebral blood volume (rCBV) define microvascular volume as an indicator of tumor-related angiogenesis. Dynamic contrast-enhanced (DCE) MRI measures of vascular permeability (Ktrans). Diffusion-weighted imaging apparent diffusion coefficient (ADC) correlates with cellular density and proliferative indices and can aid in distinguishing tumor from vasogenic edema. Diffusion tensor imaging (DTI) fractional anisotropy (FA) measures the integrity of white matter tracts, which can be used to identify regions of tumor infiltration.