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Echo-Planar-Based Time-of-Flight Imaging Using a Modified Interleaved Flyback Trajectory
Simon Blömer1,2, Tony Stöcker1,2, Rüdiger Stirnberg1
1German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
Purpose:
A modified interleaved flyback (miFB) approach is introduced, designed to mitigate flow artifacts caused by alternating readout polarities in Echo Planar Imaging (EPI), while preserving acquisition efficiency.
Methods:
We propose reconstructing odd and even echoes of 3D-EPI separately. To this end, the respective missing lines are acquired in interleaved shots with inverted polarity and an additional gradient pre-lobe. Thereby, high scan efficiency is maintained compared to unsampled flyback gradients. Our miFB approach is additionally combined with gradient moment smoothing and compared to the interleaved dual-echo with acceleration (IDEA) method in phantom and in vivo scans at 7 Tesla.
Results:
Our results demonstrate a significant reduction in ghosting and signal dropout using the miFB approach, yielding comparable image quality to non-EPI acquisitions while reducing acquisition time by approximately half.
Conclusion:
The miFB approach offers a substantial reduction in flow artifacts, allowing for decreased acquisition times in TOF-MRA.
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