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Investig Magn Reson Imaging. 2017 Dec;21(4):210-222. English. Original Article. https://doi.org/10.13104/imri.2017.21.4.210
Martin T , Wang Y , Rashid S , Shao X , Moeller S , Hu P , Sung K , Wang DJ .
Department of Radiological Sciences, University of California Los Angeles, California, USA.
Philips, MR Clinical Science NA, Florida, USA.
Laboratory of FMRI Technology (LOFT), Stevens Neuroimaging and Informatics Institute, University of Southern California, California, USA. jwang71@gmail.com
Center of Magnetic Resonance Research, University of Minnesota, Minnesota, USA.
Abstract

Purpose

To develop a novel combination of controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) with integrated SSFP (CAIPI-iSSFP) for accelerated SSFP imaging without banding artifacts at 3T.

Materials and Methods

CAIPI-iSSFP was developed by adding a dephasing gradient to the balanced SSFP (bSSFP) pulse sequence with a gradient area that results in 2π dephasing across a single pixel. Extended phase graph (EPG) simulations were performed to show the signal behaviors of iSSFP, bSSFP, and RF-spoiled gradient echo (SPGR) sequences. In vivo experiments were performed for brain and abdominal imaging at 3T with simultaneous multi-slice (SMS) acceleration factors of 2, 3 and 4 with CAIPI-iSSFP and CAIPI-bSSFP. The image quality was evaluated by measuring the relative contrast-to-noise ratio (CNR) and by qualitatively assessing banding artifact removal in the brain.

Results

Banding artifacts were removed using CAIPI-iSSFP compared to CAIPI-bSSFP up to an SMS factor of 4 and 3 on brain and liver imaging, respectively. The relative CNRs between gray and white matter were on average 18% lower in CAIPI-iSSFP compared to that of CAIPI-bSSFP.

Conclusion

This study demonstrated that CAIPI-iSSFP provides up to a factor of four acceleration, while minimizing the banding artifacts with up to a 20% decrease in the relative CNR.

Copyright © 2019. Korean Association of Medical Journal Editors.