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. Author manuscript; available in PMC: 2016 Oct 25.
Published in final edited form as: J Magn Reson Imaging. 2015 Jul 14;43(1):28–44. doi: 10.1002/jmri.24997

FIGURE 9.

FIGURE 9

Subsampling in combination with efficient constrained reconstruction allows for improved time resolution in comparison to Nyquist sampling; a spiral-based acquisition as depicted in Protocol 2 is used. Images reconstructed using (a) Nyquist sampling and online gridding reconstruction result in time resolution of 78 msec/frame, while (b) sub-Nyquist sampling and online gridding reconstruction allows for significantly improved time resolution, at the expense of aliasing artifacts. Offline constrained reconstruction addresses this tradeoff by resolving the aliasing at the native time resolution of 12 msec/frame. Note the apparent advantage of the increase in time resolution of (c) vs. (a) in terms of crispness along the time axis. The task was to repeatedly count numbers “one-two-three-four-five” at a rapid pace (the subject spoke ~4 times faster than his normal speech pace).