The spectrum of electromagnetic waves. The concept of penetrability of RF. The thermal effect. The phenomenon of magnetic resonance. The Larmor theorem. The relaxation time T1. The relaxation time T2. Pulse sequences. The RM parameters (TR, TE, FA). The Spin Echo sequence and the contrast as a function of the TR and TE. The Inversion Recovery sequence and the contrast in function of the TR, TI and TE. The Gradient Echo sequence and the contrast as a function of the TR, FA and TE. The spatial encoding of the RM signal. The single volume technique; the angle-frequency technique; the phase-frequency technique. Multislice acquisition. The K space.