Kimberly D. Brewer1,2, Chris V. Bowen2,3, Steven D. Beyea2,3
1Department of Physics, Dalhousie University, Halifax, Nova Scotia, Canada; 2Institute for Biodiagnostics (Atlantic), National Research Council of Canada, Halifax, Nova Scotia, Canada; 3Departments of Physics, Radiology and Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
Pulse sequences using reverse spiral trajectories (i.e. Spiral-In) are commonly used to avoid signal loss and distortion in regions with susceptibility field gradients (SFGs). Although there have been theories postulated as to why Spiral-In is superior to Spiral-Out, none of them explain why Spiral-In continues to recover more signal in SFG regions, even when acquired with an acquisition window that begins after that of Spiral-Out. We explored this phenomenon further through use of a phantom that produces well-known field patterns as well as computer simulations.
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