FIG. 1.
Examples of (a) COMP T2prep and (b) the proposed adiabatic tan/tanh mBIR-4 T2prep for MWF mapping of the brain at 3T. In the COMP design, multiple 90x180y90x composite pulses were used to refocus the transverse magnetization at fixed regular intervals (echo spacing (ESP) = 5 ms in this example) to produce spin echoes that underwent T2 relaxation. The proposed mBIR-4 design consisted of three frequency-modulated adiabatic RF pulses with larger amplitudes and longer duration to achieve more robust T2 weighting in the presence of increased field inhomogeneities at 3T.
