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Off‐centered spiral trajectories
Author(s) -
Tsai ChiMing,
Man LaiChee,
Nishimura Dwight G.
Publication year - 2000
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/(sici)1522-2594(200003)43:3<446::aid-mrm17>3.0.co;2-d
Subject(s) - spiral (railway) , computer science , trajectory , sampling (signal processing) , residual , waveform , computer vision , data acquisition , contrast (vision) , artificial intelligence , algorithm , mathematics , physics , telecommunications , radar , filter (signal processing) , astronomy , operating system , mathematical analysis
The quality of spiral images depends on the accuracy of the k ‐space sampling locations. Although newer gradient systems can provide more accurate gradient waveforms, the sampling positions can be significantly distorted by timing misregistration between data acquisition and gradient systems. Even after the timing of data acquisition is tuned, minor residual errors can still cause shading artifacts which are problematic for quantitative MR applications such as phase‐contrast flow quantitation. These timing errors can ideally be corrected by measuring the actual k ‐space trajectory, but trajectory measurement requires additional data acquisition and scan time. Therefore, off‐centered spiral trajectories which are more robust against timing errors are proposed and applied to the phase‐contrast method. The new trajectories turn shading artifacts into a slowly varying linear phase in reconstructed images without affecting the magnitude of images. Magn Reson Med 43:446–451, 2000. © 2000 Wiley‐Liss, Inc.