title: Approximation error method can reduce artifacts due to scalp blood flow in optical brain activation imaging.
abstract: Diffuse optical tomography can image the hemodynamic response to an activation in the human brain by measuring changes in optical absorption of near-infrared light. Since optodes placed on the scalp are used, the measurements are very sensitive to changes in optical attenuation in the scalp, making optical brain activation imaging susceptible to artifacts due to effects of systemic circulation and local circulation of the scalp. We propose to use the Bayesian approximation error approach to reduce these artifacts. The feasibility of the approach is evaluated using simulated brain activations. When a localized cortical activation occurs simultaneously with changes in the scalp blood flow, these changes can mask the cortical activity causing spurious artifacts. We show that the proposed approach is able to recover from these artifacts even when the nominal tissue properties are not well known.
authors.affiliation: University College London, Department of Computer Science, Gower Street, London WC1E 6BT, United Kingdom. j.heiskala@cs.ucl.ac.uk
authors.forename: Juha
authors.initials: J
authors.lastname: Heiskala
authors.forename: Ville
authors.initials: V
authors.lastname: Kolehmainen
authors.forename: Tanja
authors.initials: T
authors.lastname: Tarvainen
authors.forename: Jari P
authors.initials: JP
authors.lastname: Kaipio
authors.forename: Simon R
authors.initials: SR
authors.lastname: Arridge
mesh_terms: D000328:Adult; D000465:Algorithms; D016477:Artifacts; D001783:Blood Flow Velocity / Q000502:physiology; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D003198:Computer Simulation; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008297:Male; D008954:Models, Biological; D010092:Oximetry / Q000379:methods*; D010101:Oxygen Consumption / Q000502:physiology; D015203:Reproducibility of Results; D012535:Scalp / Q000098:blood supply / Q000502:physiology*; D012680:Sensitivity and Specificity; D019265:Spectroscopy, Near-Infrared / Q000379:methods*