Accelerated Simultaneous Multi-Slice (SMS) fMRI using spiral acquisition and low rank plus sparse (L+S) image reconstruction

Andrii Y Petrov^{1}, Michael Herbst^{1,2}, and V Andrew Stenger^{1}

The fMRI data can be structured as the space-time matrix M, where each column is a temporal frame, and decomposed into low-rank (L) and sparse (S) components by solving the following optimization problem:

$$ min \parallel L \parallel_*+\lambda \parallel S \parallel_1, s.t. M=W(L+S) $$

where $$$\parallel L \parallel _*$$$ and $$$\parallel S \parallel_1$$$ are the nuclear-norm and $$$l_1$$$ norms of $$$L$$$ and $$$S$$$, $$$\lambda=1/\sqrt{n_1 n_2}$$$ is the nuclear norm vs $$$l_1$$$ norm weight. The decomposition results in matrix $$$L$$$ and matrix $$$S$$$, where $$$L$$$ represents a highly-stuctured information, such as tissue, or slowly-changing periodic information, such as cardic pulsation or respiratory movement. $$$S$$$ captures less-structured information, such as new localized dynamic information. $$$L+S$$$ results in matrix $$$M$$$ that represents background information with overlaid localized dynamic components.

In this work we demonstrated that a spiral SMS acquisition combined with L+S reconstruction can accelerate fMRI acquisition by a factor of x4. We have also shown that L+S algorithm is able to produce slice aliasing corrected images and successfully decompose them into L and S components comparable with the those obtained from the fully sampled data. Future work will be to add coil sensitivity encoding for higher acceleration than SMS with parallel imaging alone. We will also add blipped-spiral acquisitors for improved k_{z}-t sampling^{6}.

1. Feinberg, D.A., Moeller, S., Smith, S.M., et al. Multiplexed echo planar imaging for sub-second whole brain fMRI and fast diffusion imaging. PLoS One . 2010; 5 (12), e15710.

2. Larkman DJ, Hajnal JV, Herlihy AH, Coutts GA, Young IR, Ehnholm G. Use of multicoil arrays for separation of signal from multiple slices simultaneously excited. J Magn Reson Imaging. 2001;13(2):313-7.

3. Setsompop K, Gagoski BA, Polimeni JR, Witzel T, Wedeen VJ, Wald LL. Blipped-controlled aliasing in parallel imaging for simultaneous multislice echo planer imaging with reduced g-factor penalty. Magn Reson Med. 2011. Epub 2011/08/23.

4. Griswold, M.A., Jakob, P.M., Heidemann, R.M., et al. Generalized autocalibrating partially parallel acquisitions (GRAPPA). 612 Magn. Reson. Med. 2002; 47 (6): 1202–1210.

5. Pruessmann KP, Weiger M, Scheidegger MB, Boesiger P. SENSE: Sensitivity encoding for fast MRI. Magnetic Resonance in Medicine. 1999;42:952-62.

6. Zahneisen B, Poser BA, Ernst T, Stenger AV. Simultaneous Multi-Slice fMRI using spiral trajectories. Neuroimage. 2014;92:8-18.

Proc. Intl. Soc. Mag. Reson. Med. 24 (2016)

3258