Three dimensional echo-planar imaging at 7 Tesla

By Benedikt A. Poser, Peter J. Koopmans, Thomas Witzel, Lawrence L. Wald, Markus Barth. NeuroImage, 2010

309 citations recorded by the source corpus.

Functional MRI (fMRI) most commonly employs 2D echo-planar imaging (EPI). The advantages for fMRI brought about by the increasingly popular ultra-high field strengths are best exploited in high-resolution acquisitions, but here 2D EPI becomes unpractical for several reasons, including the very long volume acquisitions times. In this study at 7 T, a 3D EPI sequence with full parallel and partial Fourier imaging capability along both phase encoding axes was implemented and used to evaluate the sensitivity of 3D and corresponding 2D EPI acquisitions at four different spatial resolutions ranging from small to typical voxel sizes (1.5–3.0mm isotropic). Whole-brain resting state measurements (N=4) revealed a better, or at least comparable sensitivity of the 3D method for gray and white matter. The larger vulnerability of 3D to physiological effects was outweighed by the much shorter volume TR, which moreover allows whole brain coverage at high resolution within fully acceptable limits for event-related fMRI: TR was only 3.07s for 1.5 mm, 1.88 s for 2.0mm, 1.38 s for 2.5 mm and 1.07s for 3.0 mm isotropic resolution. In order to investigate the ability to detect and spatially resolve BOLD activation in the visual cortex, functional 3D EPI experiments (N=8) were performed at 1mm isotropic resolution with parallel imaging acceleration of 3×3, resulting in a TR of only 3.2s for whole-brain coverage. From our results, and several other practical advantages of 3D over 2D EPI found in the present study, we conclude that 3D EPI provides a useful alternative for whole-brain fMRI at 7 Tesla, not only when high-resolution data are required.

Subfields: Radiation, Radiology, Nuclear Medicine and Imaging

View Paper: https://www.semanticscholar.org/paper/ea1d1374ea52d974fd7f756d56955b8fcde3a6fa

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Citations in the corpus

Pushing spatial and temporal resolution for functional and diffusion MRI in the Human Connectome Project (2013, methodology): “Three dimensional (3D) echo volume imaging (EVI) (Mansfield et al., 1994), Segmented Multi-shot 3D EPI (Poser et al., 2010; Wielopolski et al., 1995), Echo shifting approaches such as PRESTO (Golay et al., 2000; Liu et al., 1993), the simultaneous image refocused (SIR) scheme (Feinberg et al.,…”
Methods for cleaning the BOLD fMRI signal (2016, unknown): “…2D EPI acquisitions, in recent years multi-shot 3D EPI acquisitions are becoming increasingly popular at 3 T and 7 T to achieve high spatial resolution with larger SNR values than their 2D counterparts (Jorge et al., 2013; Narsude et al., 2016; Poser et al., 2010; van der Zwaag et al., 2012).”
Multiplexed Echo Planar Imaging for Sub-Second Whole Brain FMRI and Fast Diffusion Imaging (2010, background): “As such, it was shown that 3D acquisition times could be reduced to levels near or faster than what is obtained with 2D multi-slice imaging, greatly improving the performance of 3D functional images over 2D [15,39].”
Evaluation of slice accelerations using multiband echo planar imaging at 3 Tesla (2013, unknown): “Multi-shot segmented EVI along with parallel imaging can significantly alleviate these problems (Poser et al., 2010; Posse et al., 2012;Wielopolski et al., 1995).”