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Abstract #3813

EPI gradient trajectory noise measurement and simulation of related artifacts

Niklas Wehkamp1, Qingping Chen1, Patrick Hucker1, Johannes Fischer1, Sebastian Littin1, Jon-Fredrik Nielsen2, and Maxim Zaitsev1
1Division of Medical Physics, Department of Diagnostic and Interventional Radiology, University Medical Center Freiburg, Freiburg, Germany, 2Functional MRI Laboratory, Department of Radiology, University of Michigan, Ann Arbor, MI, United States

Synopsis

Keywords: System Imperfections, System Imperfections: Measurement & Correction, field camera, field probes, stability, trajectory, simulation, MRzero, Pulseq

Motivation: Analyze the origin of "cloudy ghost" artifacts observed during quality assurance in temporal-fluctuation-noise-images from 10-minute Echo-planar imaging, to understand and improve consistency of fMRI-based neuroimaging.

Goal(s): Determine gradient behavior differences between two 3T MRI systems and link them to the observed “cloudy ghost” artifacts.

Approach: We measured the gradient trajectory of a standard Echo-planar Imaging sequence with a dynamic field camera at two MRI systems and simulated artifacts based on individual components of the measured trajectory.

Results: A simulation routine based on Pulseq and the MRzero framework was developed, that can partially reproduce the observed artifacts from measured zero and first-order trajectory deviations.

Impact: Enhance understanding of gradient related artifact sources in fMRI neuroimaging studies. Our open-source simulation routine allows to partially reproduce artifacts from dynamic zero and first-order trajectory deviations. The improved understanding lays the groundwork for development of more reliable future MRI-systems.

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Keywords