Fig 2. A, The NAA-nulling sequence comprising a BIR4 adiabatic 180° (every second) acquisition followed by a TI = 940 ms to null the NAA signal intensity. WET and a 13 (100-µs rectangular pulses, 2-ms delays at 3T) for a 90° readout with acquisition commencing immediately. Each even transient is subtracted from every odd. Because the TR is long, 10 seconds, and TE 0, minimal T1 or T2 weighting is incurred by the NAA. B, An alternative approach in which the lipids (not the NAA) are nulled with TI = 155 ms. All other pulses and sequence parameters are shared with A. Note that all pulses in either sequence are non-spatial-selective and that the gradient "blips," Gx, Gy, and Gz (all 5 mT/m), therefore, are just crushers. RF indicates radio-frequency.