Sweep-diagram analysis of selective adiabatic pulses

In the conventional perspective of adiabatic fast passage (AFP), the slice profile is considered to be the result of energy deposited in a sweep of instantaneous frequency through a specific bandwidth. We introduce an efficient and powerful technique for analyzing selective adiabatic pulses. One need only draw the excitation trajectory at all offset frequencies of interest. The drawings predict the final orientation of the magnetization vectors at the end of a selective adiabatic pulse. AFP pulses' insensitivity to RF variations is obvious when viewed in a sweep diagram. Furthermore, the sweep-diagram technique has facilitated the design of several new AFP pulses. Here, we illustrate the design of two selective 2π pulses, a selective and nonselective 0 pulse, and a selective spin-echo pulse.