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High‐resolution human diffusion tensor imaging using 2‐D navigated multishot SENSE EPI at 7 T
Author(s) -
Jeong HaKyu,
Gore John C.,
Anderson Adam W.
Publication year - 2012
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.24320
Subject(s) - aliasing , computer science , diffusion mri , iterative reconstruction , computer vision , image resolution , nuclear magnetic resonance , acceleration , artificial intelligence , physics , magnetic resonance imaging , undersampling , medicine , classical mechanics , radiology
The combination of parallel imaging with partial Fourier acquisition has greatly improved the performance of diffusion‐weighted single‐shot EPI and is the preferred method for acquisitions at low to medium magnetic field strength such as 1.5 or 3 T. Increased off‐resonance effects and reduced transverse relaxation times at 7 T, however, generate more significant artifacts than at lower magnetic field strength and limit data acquisition. Additional acceleration of k‐space traversal using a multishot approach, which acquires a subset of k‐space data after each excitation, reduces these artifacts relative to conventional single‐shot acquisitions. However, corrections for motion‐induced phase errors are not straightforward in accelerated, diffusion‐weighted multishot EPI because of phase aliasing. In this study, we introduce a simple acquisition and corresponding reconstruction method for diffusion‐weighted multishot EPI with parallel imaging suitable for use at high field. The reconstruction uses a simple modification of the standard sensitivity‐encoding (SENSE) algorithm to account for shot‐to‐shot phase errors; the method is called image reconstruction using image‐space sampling function (IRIS). Using this approach, reconstruction from highly aliased in vivo image data using 2‐D navigator phase information is demonstrated for human diffusion‐weighted imaging studies at 7 T. The final reconstructed images show submillimeter in‐plane resolution with no ghosts and much reduced blurring and off‐resonance artifacts. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.