title: Quantifying fluctuations of resting state networks using arterial spin labeling perfusion MRI.
abstract: Blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) has been widely used to investigate spontaneous low-frequency signal fluctuations across brain resting state networks. However, BOLD only provides relative measures of signal fluctuations. Arterial Spin Labeling (ASL) MRI holds great potential for quantitative measurements of resting state network fluctuations. This study systematically quantified signal fluctuations of the large-scale resting state networks using ASL data from 20 healthy volunteers by separating them from global signal fluctuations and fluctuations caused by residual noise. Global ASL signal fluctuation was 7.59% ± 1.47% relative to the ASL baseline perfusion. Fluctuations of seven detected resting state networks vary from 2.96% ± 0.93% to 6.71% ± 2.35%. Fluctuations of networks and residual noise were 6.05% ± 1.18% and 6.78% ± 1.16% using 4-mm resolution ASL data applied with Gaussian smoothing kernel of 6mm. However, network fluctuations were reduced by 7.77% ± 1.56% while residual noise fluctuation was markedly reduced by 39.75% ± 2.90% when smoothing kernel of 12 mm was applied to the ASL data. Therefore, global and network fluctuations are the dominant structured noise sources in ASL data. Quantitative measurements of resting state networks may enable improved noise reduction and provide insights into the function of healthy and diseased brain.
authors.affiliation: Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA, USA wdai@bidmc.harvard.edu.
authors.forename: Weiying
authors.initials: W
authors.lastname: Dai
authors.affiliation: Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors.forename: Gopal
authors.initials: G
authors.lastname: Varma
authors.affiliation: Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors.forename: Rachel
authors.initials: R
authors.lastname: Scheidegger
authors.affiliation: Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Alsop
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply* / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D012146:Rest / Q000502:physiology; D013113:Spin Labels; D055815:Young Adult
chemical_list: D013113:Spin Labels
keywords: Arterial spin labeling; functional MRI; functional connectivity; perfusion; resting-state fluctuations