scholarly journals A plug‐and‐play, lightweight, single‐axis gradient insert design for increasing spatiotemporal resolution in echo planar imaging‐based brain imaging

2021 ◽  
Author(s):  
Edwin Versteeg ◽  
Tijl A. Velden ◽  
Carel C. Leeuwen ◽  
Martino Borgo ◽  
Erik R. Huijing ◽  
...  
Keyword(s):  
Brain Imaging ◽  
Echo Planar Imaging ◽  
Planar Imaging ◽  
Spatiotemporal Resolution ◽  
Plug And Play ◽  
Echo Planar

scholarly journals Segmented K-Space Blipped-Controlled Aliasing in Parallel Imaging (Skipped-CAIPI) for High Spatiotemporal Resolution Echo Planar Imaging

2020 ◽  
Author(s):  
Rüdiger Stirnberg ◽  
Tony Stöcker
Keyword(s):  
High Resolution ◽  
Parallel Imaging ◽  
Echo Planar Imaging ◽  
Planar Imaging ◽  
Signal To Noise ◽  
Spatiotemporal Resolution ◽  
High Spatiotemporal Resolution ◽  
Selective Approach ◽  
Echo Planar ◽  
Phase Encode

AbstractPurposeA segmented k-space blipped-CAIPI (skipped-CAIPI) sampling strategy for echo planar imaging (EPI) is proposed, which allows for a flexible choice of EPI factor and phase encode bandwidth independent of the controlled aliasing (CAIPIRINHA) pattern.Theory and MethodsWith previously proposed approaches, exactly two EPI trajectories were possible given a specific CAIPIRINHA pattern: either with slice gradient blips (blipped-CAIPI), or following a shot-selective approach (higher resolution). Recently, interleaved multi-shot segmentation along shot-selective CAIPI trajectories has been applied for high-resolution anatomical imaging. For more flexibility and a broader range of applications, we propose segmentation along any blipped-CAIPI trajectory. Thus, all EPI factors and phase encode bandwidths available with traditional segmented EPI can be combined with controlled aliasing.ResultsTemporal signal-to-noise ratios of moderate-to-high-resolution time series acquisitions at varying undersampling factors demonstrate beneficial sampling alternatives to blipped-CAIPI or shot-selective CAIPI. Rapid high-resolution scans furthermore demonstrate SNR-efficient and motion-robust structural imaging with almost arbitrary EPI factor and minimal noise penalty.ConclusionsSkipped-CAIPI sampling increases protocol flexibility for high spatiotemporal resolution EPI. In terms of signal-to-noise ratio and efficiency, high-resolution functional or structural scans benefit vastly from a free choice of the CAIPIRINHA pattern. Even at moderate resolutions, the independence of sampling pattern, echo time and image matrix size is valuable for optimized functional protocol design. Although demonstrated with 3D-EPI, skipped-CAIPI is also applicable with simultaneous multislice EPI.

scholarly journals Magnetic resonance advection imaging of cerebrovascular pulse dynamics

2016 ◽  
Vol 37 (4) ◽  
pp. 1223-1235 ◽  
Author(s):  
Henning U Voss ◽  
Jonathan P Dyke ◽  
Karsten Tabelow ◽  
Nicholas D Schiff ◽  
Douglas J Ballon
Keyword(s):  
Magnetic Resonance ◽  
Pulse Wave ◽  
Pulse Signal ◽  
Echo Planar Imaging ◽  
Imaging Data ◽  
Planar Imaging ◽  
Spatiotemporal Resolution ◽  
Data Set ◽  
Wave Velocities ◽  
Echo Planar

We analyze the pulsatile signal component of dynamic echo planar imaging data from the brain by modeling the dependence between local temporal and spatial signal variability. The resulting magnetic resonance advection imaging maps depict the location of major arteries. Color direction maps allow for visualization of the direction of blood vessels. The potential significance of magnetic resonance advection imaging maps is demonstrated on a functional magnetic resonance imaging data set of 19 healthy subjects. A comparison with the here introduced pulse coherence maps, in which the echo planar imaging signal is correlated with a cardiac pulse signal, shows that the magnetic resonance advection imaging approach results in a better spatial definition without the need for a pulse reference. In addition, it is shown that magnetic resonance advection imaging velocities can be estimates of pulse wave velocities if certain requirements are met, which are specified. Although for this application magnetic resonance advection imaging velocities are not quantitative estimates of pulse wave velocities, they clearly depict local pulsatile dynamics. Magnetic resonance advection imaging can be applied to existing dynamic echo planar imaging data sets with sufficient spatiotemporal resolution. It is discussed whether magnetic resonance advection imaging might have the potential to evolve into a biomarker for the health of the cerebrovascular system.

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