title: Integrated SSFP for functional brain mapping at 7T with reduced susceptibility artifact.
abstract: Balanced steady-state free precession (bSSFP) offers an alternative and potentially important tool to the standard gradient-echo echo-planar imaging (GE-EPI) for functional MRI (fMRI). Both passband and transition band based bSSFP have been proposed for fMRI. The applications of these methods, however, are limited by banding artifacts due to the sensitivity of bSSFP signal to off-resonance effects. In this article, a unique case of the SSFP-FID sequence, termed integrated-SSFP or iSSFP, was proposed to overcome the obstacle by compressing the SSFP profile into the width of a single voxel. The magnitude of the iSSFP signal was kept constant irrespective of frequency shift. Visual stimulation studies were performed to demonstrate the feasibility of fMRI using iSSFP at 7T with flip angles of 4° and 25°, compared to standard bSSFP and gradient echo (GRE) imaging. The signal changes for the complex iSSFP signal in activated voxels were 2.48±0.53 (%) and 2.96±0.87 (%) for flip angles (FA) of 4° and 25° respectively at the TR of 9.88ms. Simultaneous multi-slice acquisition (SMS) with the CAIPIRIHNA technique was carried out with iSSFP scanning to detect the anterior temporal lobe activation using a semantic processing task fMRI, compared with standard 2D GE-EPI. This study demonstrates the feasibility of iSSFP for fMRI with reduced susceptibility artifacts, while maintaining robust functional contrast at 7T.
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Kaibao
authors.initials: K
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; Beijing Institute for Brain Disorders, Beijing 100053, China. Electronic address: rxue@bcslab.ibp.ac.cn.
authors.forename: Rong
authors.initials: R
authors.lastname: Xue
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Zhentao
authors.initials: Z
authors.lastname: Zuo
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Zhongwei
authors.initials: Z
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.affiliation: Department of Neurology, University of California Los Angeles, Los Angeles 90095, United States.
authors.forename: Thomas
authors.initials: T
authors.lastname: Martin
authors.affiliation: Department of Neurology, University of California Los Angeles, Los Angeles 90095, United States.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; The Innovation Center of Excellence on Brain Science, Chinese Academy of Sciences, China. Electronic address: linchen@bcslab.ibp.ac.cn.
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; Department of Psychology, University of Minnesota, Minneapolis, MN 55455, United States.
authors.forename: Sheng
authors.initials: S
authors.lastname: He
authors.affiliation: Department of Neurology, University of California Los Angeles, Los Angeles 90095, United States; Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, United States.
authors.forename: Danny J J
authors.initials: DJJ
authors.lastname: Wang
mesh_terms: D000328:Adult; D000465:Algorithms; D016477:Artifacts; D001931:Brain Mapping / Q000379:methods*; D003198:Computer Simulation; D017352:Echo-Planar Imaging / Q000379:methods*; D004574:Electromagnetic Fields; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008606:Mental Processes / Q000502:physiology; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000502:physiology; D055815:Young Adult
keywords: Integrated SSFP (iSSFP); Semantic; Susceptibility artifact; Ultrahigh magnetic field; fMRI