title: Reproducibility of BOLD signal change induced by breath holding.
abstract: Blood oxygen level dependent (BOLD) contrast is influenced by some physiological factors such as blood flow and blood volume that can be a source of variability in fMRI analysis. Previous studies proposed to use the cerebrovascular response data to normalize or calibrate BOLD maps in order to reduce variability of fMRI data both among brain areas in single subject analysis and across subjects. Breath holding is one of the most widely used methods to investigate the vascular reactivity. However, little is known about the robustness and reproducibility of this procedure. In this study we investigated three different breath holding periods. Subjects were asked to hold their breath for 9, 15 or 21 s in three separate runs and the fMRI protocol was repeated after 15 to 20 days. Our data show that the BOLD response to breath holding after inspiration results in a complex shape due to physiological factors that influence the signal variation with a timing that is highly reproducible. Nevertheless, the reproducibility of the magnitude of the cerebrovascular response to CO(2), expressed as amplitude of BOLD signal and number of responding voxels, strongly depends on duration of breath holding periods. Breath holding period of 9 s results in high variability of the magnitude of the response while longer breath holding durations produce more robust and reproducible BOLD responses.
authors.affiliation: Department of Morphological-Biomedical Sciences, Section of Human Anatomy and Histology, University of Verona, Verona, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Magon
authors.forename: Gianpaolo
authors.initials: G
authors.lastname: Basso
authors.forename: Paolo
authors.initials: P
authors.lastname: Farace
authors.forename: Giuseppe Kenneth
authors.initials: GK
authors.lastname: Ricciardi
authors.forename: Alberto
authors.initials: A
authors.lastname: Beltramello
authors.forename: Andrea
authors.initials: A
authors.lastname: Sbarbati
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D010100:Oxygen / Q000097:blood; D015203:Reproducibility of Results; D015656:Respiratory Mechanics
chemical_list: D010100:Oxygen