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Abstract #1823

Velocity-Encoding Navigator for First-Order Motion Compensation in Diffusion MRI

Bo Li1 and Thomas Ernst1
1Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland, Baltimore, Baltimore, MD, United States

Synopsis

Keywords: Motion Correction, Diffusion/other diffusion imaging techniques, velocity navigatorUncorrected head rotations during diffusion weighted imaging (DWI) can induce gradient imbalances that may shift the echo outside of the k-space window and cause signal dropouts. Therefore, we developed a rotational velocity navigator (~10ms duration) that is acquired immediately after each excitation and estimates the rotational velocities perpendicular to the diffusion gradient. The accuracy of estimated velocities was 4.1°/s relative to an optical tracking system (“gold standard”). Ultimately, the rotational velocities can predict the gradient moment error in first order, and a gradient blip can be applied to recenter the echo in k-space.

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Keywords