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Tilted‐CAIPI for highly accelerated distortion‐free EPI with point spread function (PSF) encoding
Author(s) -
Dong Zijing,
Wang Fuyixue,
Reese Timothy G.,
Manhard Mary Katherine,
Bilgic Berkin,
Wald Lawrence L.,
Guo Hua,
Setsompop Kawin
Publication year - 2019
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.27413
Subject(s) - distortion (music) , computer science , diffusion mri , point spread function , image quality , artificial intelligence , phase (matter) , computer vision , iterative reconstruction , encoding (memory) , optics , physics , algorithm , magnetic resonance imaging , image (mathematics) , telecommunications , medicine , amplifier , bandwidth (computing) , quantum mechanics , radiology
Purpose To develop a method for fast distortion‐ and blurring‐free imaging. Theory: EPI with point‐spread‐function (PSF) mapping can achieve distortion‐ and blurring‐free imaging at a cost of long acquisition time. In this study, an acquisition/reconstruction technique, termed “tilted‐CAIPI,” is proposed to achieve >20× acceleration for PSF‐EPI. The proposed method systematically optimized the k‐space sampling trajectory with B 0 ‐inhomogeneity‐informed reconstruction, to exploit the inherent signal correlation in PSF‐EPI and take full advantage of coil sensitivity. Susceptibility‐induced phase accumulation is regarded as an additional encoding that is estimated by calibration data and integrated into reconstruction. Self‐navigated phase correction was developed to correct shot‐to‐shot phase variation in diffusion imaging. Methods Tilted‐CAIPI was implemented at 3T, with incorporation of partial Fourier and simultaneous multislice to achieve further accelerations. T 2 ‐weighted, T 2 * ‐weighted, and diffusion‐weighted imaging experiments were conducted to evaluate the proposed method. Results The ability of tilted‐CAIPI to provide highly accelerated imaging without distortion and blurring was demonstrated through in vivo brain experiments, where only 8 shots per simultaneous slice group were required to provide high‐quality, high‐SNR imaging at 0.8–1 mm resolution. Conclusion Tilted‐CAIPI achieved fast distortion‐ and blurring‐free imaging with high SNR. Whole‐brain T 2 ‐weighted, T 2 * ‐weighted, and diffusion imaging can be obtained in just 15–60 s.