Introduction to MRI Physics.

Magnetic resonance imaging (MRI) is an imaging technique derived from radiofrequency (RF) signals of proton that are magnetized by a strong magnetic field. These protons typically originate from water, fat, or metabolites. The application of RF pulses is used to excite the magnetization, whereas pulsed magnetic field gradients are used to provide spatial localization. This chapter describes the fundamental principles giving rise to MR images. Furthermore, the connection between relaxation and image contrast is discussed.