Fig. 1.
Variable refocusing flip-angle (FA) profile in the 3D pseudo-steady state (PSS) readout module. The refocusing FA rapidly decreases from around 180° to the minimum (αmin), then remains constant for the specified number of echoes in the center of the k-space (αcen); at the same time, PSS conditions can be established due to the balance of T1 and T2 relaxation. Thereafter, the refocusing FA increases gradually and linearly until the end of the echo train to obtain a higher-level signal at the periphery, as well as the center of the k-space, with the following FA settings: αmin = 120°, αcen = 120°, αmax = 180°.