title: Hybrid-Space SENSE Reconstruction for Simultaneous Multi-Slice MRI.
abstract: Simultaneous Multi-Slice (SMS) magnetic resonance imaging (MRI) is a rapidly evolving technique for increasing imaging speed. Controlled aliasing techniques utilize periodic undersampling patterns to help mitigate the loss in signal-to-noise ratio (SNR) in SMS MRI. To evaluate the performance of different undersampling patterns, a quantitative description of the image SNR loss is needed. Additionally, eddy current effects in echo planar imaging (EPI) lead to slice-specific Nyquist ghosting artifacts. These artifacts cannot be accurately corrected for each individual slice before or after slice-unaliasing. In this work, we propose a hybrid-space sensitivity encoding (SENSE) reconstruction framework for SMS MRI by adopting a three-dimensional representation of the SMS acquisition. Analytical SNR loss maps are derived for SMS acquisitions with arbitrary phase encoding undersampling patterns. Moreover, we propose a matrix-decoding correction method that corrects the slice-specific Nyquist ghosting artifacts in SMS EPI acquisitions. Brain images demonstrate that the proposed hybrid-space SENSE reconstruction generates images with comparable quality to commonly used split-slice-generalized autocalibrating partially parallel acquisition reconstruction. The analytical SNR loss maps agree with those calculated by a Monte Carlo based method, but require less computation time for high quality maps. The analytical maps enable a fair comparison between the performances of coherent and incoherent SMS undersampling patterns. Phantom and brain SMS EPI images show that the matrix-decoding method performs better than the single-slice and slice-averaged Nyquist ghosting correction methods under the hybrid-space SENSE reconstruction framework.
authors.forename: Kangrong
authors.initials: K
authors.lastname: Zhu
authors.forename: Robert F
authors.initials: RF
authors.lastname: Dougherty
authors.forename: Hua
authors.initials: H
authors.lastname: Wu
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Middione
authors.forename: Atsushi M
authors.initials: AM
authors.lastname: Takahashi
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.forename: John M
authors.initials: JM
authors.lastname: Pauly
authors.forename: Adam B
authors.initials: AB
authors.lastname: Kerr
mesh_terms: D016477:Artifacts; D001921:Brain; D017352:Echo-Planar Imaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D019047:Phantoms, Imaging; D059629:Signal-To-Noise Ratio