Vascular Magnetic Resonance Imaging in Brain Tumors During Antiangiogenic Therapy--Are We There Yet?

Abnormal tumor vasculature is a potent mediator of treatment resistance because it results in heterogeneous perfusion, hypoxia, increased interstitial fluid pressure, and incomplete penetration of cytotoxic chemotherapies. Targeting this abnormal tumor vasculature is a promising therapeutic strategy, but results with antiangiogenic drugs in brain cancer have been mixed. Vasculature's response to treatment is a dynamic physiological process that can change rapidly throughout treatment, so it requires noninvasive techniques to serially monitor these changes in order to improve outcome. We review the role of vascular magnetic resonance imaging to measure tumor response to treatment and highlight opportunities and future avenues for expanding these promising techniques.