title: Robust estimation of HDR in fMRI using H(infinity) filters.
abstract: Estimation and detection of the hemodynamic response (HDR) are of great importance in functional MRI (fMRI) data analysis. In this paper, we propose the use of three H (infinity) adaptive filters (finite memory, exponentially weighted, and time-varying) for accurate estimation and detection of the HDR. The H (infinity) approach is used because it safeguards against the worst case disturbances and makes no assumptions on the (statistical) nature of the signals [B. Hassibi and T. Kailath, in Proc. ICASSP, 1995, vol. 2, pp. 949-952; T. Ratnarajah and S. Puthusserypady, in Proc. 8th IEEE Workshop DSP, 1998, pp. 1483-1487]. Performances of the proposed techniques are compared to the conventional t-test method as well as the well-known LMSs and recursive least squares algorithms. Extensive numerical simulations show that the proposed methods result in better HDR estimations and activation detections.
authors.affiliation: Department of Electrical Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark. spu@elektro.dtu.dk
authors.forename: S
authors.initials: S
authors.lastname: Puthusserypady
authors.forename: T
authors.initials: T
authors.lastname: Ratnarajah
authors.forename: Rui
authors.initials: R
authors.lastname: Jue
authors.forename: T
authors.initials: T
authors.lastname: Ratnarajah
mesh_terms: D000465:Algorithms; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D005071:Evoked Potentials / Q000502:physiology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*
chemical_list: D010100:Oxygen