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. Author manuscript; available in PMC: 2016 Jan 31.
Published in final edited form as: Magn Reson Med. 2014 Mar 6;73(2):704–710. doi: 10.1002/mrm.25172

Figure 2.

Figure 2

Normalized MTFs of spiral in/out trajectories. MTFs are normalized to on-resonance (0 cycles) case. a) Center-frequency offset. Until ~0.5 cycles of phase are accrued, the cosine function never reaches its first zero, resulting in a relatively benign amplitude modulation in k-space; however, important frequencies are lost as the amount of off-resonance increases. b) Off-resonance due to concomitant fields. MTFs for off-resonance due to concomitant fields shows good performance can be expected up to about 1 cycle of accrued phase. c) The effect of decay during the readout. Differing amounts of T2 decay are simulated with 0.5 cycles of off-resonance phase accrual. Severe shaping of the MTF is only seen when the T2 time constant approaches the readout length (10 ms).