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Slice accelerated diffusion‐weighted imaging at ultra‐high field strength
Author(s) -
Eichner Cornelius,
Setsompop Kawin,
Koopmans Peter J.,
Lützkendorf Ralf,
Norris David G.,
Turner Robert,
Wald Lawrence L.,
Heidemann Robin M.
Publication year - 2014
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.24809
Subject(s) - aliasing , isotropy , specific absorption rate , computer science , diffusion mri , image quality , field strength , image resolution , nuclear magnetic resonance , magnetic resonance imaging , acceleration , physics , artificial intelligence , optics , magnetic field , image (mathematics) , undersampling , telecommunications , medicine , classical mechanics , quantum mechanics , antenna (radio) , radiology
Purpose Diffusion magnetic resonance imaging (dMRI) data with very high isotropic resolution can be obtained at 7T. However, for extensive brain coverage, a large number of slices is required, resulting in long acquisition times (TAs). Recording multiple slices simultaneously (SMS) promises to reduce the TA. Methods A combination of zoomed and parallel imaging is used to achieve high isotropic resolution dMRI data with a low level of distortions at 7T. The blipped‐CAIPI (controlled aliasing in parallel imaging) approach is used to acquire several slices simultaneously. Due to their high radiofrequency (RF) power deposition and ensuing specific absorption rate (SAR) constraints, the commonly used multiband (MB) RF pulses for SMS imaging are inefficient at 7T and entail long repetition times, counteracting the usefulness of SMS acquisitions. To address this issue, low SAR multislice Power Independent of Number of Slices RF pulses are employed. Results In vivo dMRI results with and without SMS acceleration are presented at different isotropic spatial resolutions at ultra high field strength. The datasets are recorded at a high angular resolution to detect fiber crossings. Conclusion From the results and compared with earlier studies at these resolutions, it can be seen that scan time is significantly reduced, while image quality is preserved. Magn Reson Med 71:1518–1525, 2014. © 2013 Wiley Periodicals, Inc .