“…It uses nuclear magnetic resonance, the intrinsic magnetic properties of protons, to produce gray-scale images in multiple planes. 25,26 The signal generated and the resulting images are based on proton density in tissues, and T1 and T2 relaxation times, which describe recovery and delay of nuclear magnetism after perturbations with an oscillating radiofrequency magnetic field. Gadolinium, an inert contrast material, may be infused intravenously to identify vascular structures and regions of breakdown in the blood-brain barrier.…”