Dynamic‐flip‐angle ECG‐gating with nuisance signal regression improves resting‐state BOLD functional connectivity mapping by reducing cardiogenic noise. Issue 3 (24th April 2019)

• Record Type: Journal Article
• Authors: Hu, Chenxi; Tokoglu, Fuyuze; Scheinost, Dustin; Qiu, Maolin; Shen, Xilin; Peters, Dana C.; Galiana, Gigi; Constable, R. Todd
• Is Part Of: Magnetic resonance in medicine. Volume 82:Issue 3(2019)
• Page Start: 911
• Page End: 923
• Publication Date: 2019-04-24
• Subjects: dynamic flip angle -- ECG‐gating -- nuisance signal regression -- resting‐state fMRI -- subcortical–cortical -- subcortical–subcortical; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.27775
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : Purpose: To investigate an ECG‐gated dynamic‐flip‐angle BOLD sequence with improved robustness against cardiogenic noise in resting‐state fMRI. Methods: ECG‐gating minimizes the cardiogenic noise but introduces T1 ‐dependent signal variation, which is minimized by combination of a dynamic‐flip‐angle technique and retrospective nuisance signal regression (NSR) using signals of white matter, CSF, and global average. The technique was studied with simulations in a wide range of T1 and B1 fields and phantom imaging with pre‐programmed TR variations. Resting‐state fMRI of 20 healthy subjects was acquired with non‐gated BOLD (NG), ECG‐gated constant‐flip‐angle BOLD (GCFA), ECG‐gated BOLD with retrospective T1 ‐correction (GRC), and ECG‐gated dynamic‐flip‐angle BOLD (GDFA), all processed by the same NSR method. GDFA was compared to alternative methods over temporal SNR (tSNR), seed‐based connectivity, and whole‐brain voxelwise connectivity based on intrinsic connectivity distribution (ICD). A previous large‐cohort data set ( N = 100) was used as a connectivity gold standard. Results: Simulations and phantom imaging show substantial reduction of the T1 ‐dependent signal variation with GDFA alone, and further reduction with NSR. The resting‐state study shows improved tSNR in the basal brain, comparing GDFA to NG, after both processed with NSR. Furthermore, GDFA significantly improved subcortical–subcortical and cortical–subcortical connectivity for several representative seeds and significantly improved ICD in the brainstem, thalamus, striatum, and prefrontal cortex, compared to the other 3 approaches. Conclusion: GDFA with NSR improves mapping of the resting‐state functional connectivity of the basal–brain regions by reducing cardiogenic noise.