Accelerated spin-echo functional MRI using multisection excitation by simultaneous spin-echo interleaving (MESSI) with complex-encoded generalized slice dithered enhanced resolution (cgSlider) simultaneous multislice echo-planar imaging

SoHyun Han; Congyu Liao; Mary Kate Manhard; Daniel Joseph Park; Berkin Bilgic; Merlin J Fair; Fuyixue Wang; Anna I Blazejewska; William A Grissom; Jonathan R Polimeni; Kawin Setsompop

doi:10.1002/mrm.28108

Accelerated spin-echo functional MRI using multisection excitation by simultaneous spin-echo interleaving (MESSI) with complex-encoded generalized slice dithered enhanced resolution (cgSlider) simultaneous multislice echo-planar imaging

Magn Reson Med. 2020 Jul;84(1):206-220. doi: 10.1002/mrm.28108. Epub 2019 Dec 16.

Authors

SoHyun Han^{1

2}, Congyu Liao^{1

2}, Mary Kate Manhard^{1

2}, Daniel Joseph Park¹, Berkin Bilgic^{1

2}, Merlin J Fair^{1

2}, Fuyixue Wang^{1

3}, Anna I Blazejewska^{1

2}, William A Grissom⁴, Jonathan R Polimeni^{1

2

5}, Kawin Setsompop^{1

2

5}

Affiliations

¹ Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts.
² Department of Radiology, Harvard Medical School, Boston, Massachusetts.
³ Medical Engineering & Medical Physics, Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts.
⁴ Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA.
⁵ Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts.

Abstract

Purpose: Spin-echo functional MRI (SE-fMRI) has the potential to improve spatial specificity when compared with gradient-echo fMRI. However, high spatiotemporal resolution SE-fMRI with large slice-coverage is challenging as SE-fMRI requires a long echo time to generate blood oxygenation level-dependent (BOLD) contrast, leading to long repetition times. The aim of this work is to develop an acquisition method that enhances the slice-coverage of SE-fMRI at high spatiotemporal resolution.

Theory and methods: An acquisition scheme was developed entitled multisection excitation by simultaneous spin-echo interleaving (MESSI) with complex-encoded generalized slice dithered enhanced resolution (cgSlider). MESSI uses the dead-time during the long echo time by interleaving the excitation and readout of 2 slices to enable 2× slice-acceleration, while cgSlider uses the stable temporal background phase in SE-fMRI to encode/decode 2 adjacent slices simultaneously with a "phase-constrained" reconstruction method. The proposed cgSlider-MESSI was also combined with simultaneous multislice (SMS) to achieve further slice-acceleration. This combined approach was used to achieve 1.5-mm isotropic whole-brain SE-fMRI with a temporal resolution of 1.5 s and was evaluated using sensory stimulation and breath-hold tasks at 3T.

Results: Compared with conventional SE-SMS, cgSlider-MESSI-SMS provides 4-fold increase in slice-coverage for the same repetition time, with comparable temporal signal-to-noise ratio. Corresponding fMRI activation from cgSlider-MESSI-SMS for both fMRI tasks were consistent with those from conventional SE-SMS. Overall, cgSlider-MESSI-SMS achieved a 32× encoding-acceleration by combining R_inplane × MB × cgSlider × MESSI = 4 × 2 × 2 × 2.

Conclusion: High-quality, high-resolution whole-brain SE-fMRI was acquired at a short repetition time using cgSlider-MESSI-SMS. This method should be beneficial for high spatiotemporal resolution SE-fMRI studies requiring whole-brain coverage.

Keywords: GSlider; Hadamard encoding; functional imaging; slice interleaving; spin echo.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Brain / diagnostic imaging
Brain Mapping*
Echo-Planar Imaging*
Image Processing, Computer-Assisted
Magnetic Resonance Imaging
Signal-To-Noise Ratio

Abstract

Publication types

MeSH terms

Grants and funding