The Multidimensional MRI TR&D plans to investigate novel microstructure imaging technologies, and biophysical models to better characterize brain tumor type and grade. The proposed technology will enable investigation into the heterogeneity of tumor microstructure, which has important treatment implications not only during surgery, but also for biopsy guidance and drug delivery. We propose to utilize q-space trajectory imaging (QTI), a generalized form of diffusion MRI method that dynamically changes the gradient orientation during acquisition of each diffusion-weighted image to better measure the true complexity of water molecular motion, increasing our ability to recover information about tissue microstructure. This will be augmented with additional measurement dimensions by including numerous T1 and T2 weightings to obtain a joint correlation-based marker of tissue microstructure. These new image contrasts are expected to enable novel quantitative measures of tumor microstructure that are relevant for clinical assessment. Our recent results in human brain tumors show that QTI can better capture tumor characteristics, distinguishing different tumor microstructures that cannot be differentiated using traditional methods such as diffusion tensor imaging (DTI) or diffusion spectrum imaging (DSI).