BIOMEDIZINISCHE

MAGNETRESONANZ

 Introduction
In spatially selective excitation, we restrict the generated MR signals to a two-dimensional plane or slab, which we call slice, within a patient by applying an RF excitation pulse and a slice selection gradient at the same time. The duration and amplitude of an RF pulse determines the amount of the resulting rotation of the magnetization within the slice called flip angle. We take discrete RF and gradient pulses of finite duration (6 ms) and sample them every 10 us. RF pulses are complex, having both amplitude and phase for each discrete sample. For on-resonance magnetization, flip angles of amplitude modulated RF pulses such as SINC and Gaussian are directly proportional to the time integral of the B1 fields of each sample. T1 and T2 times are assumed to be 600 and 100 ms respectively and off-resonance frequency is from -200 Hz to 200 Hz for all simulations.