title: Deconvolution with simple extrapolation for improved cerebral blood flow measurement in dynamic susceptibility contrast magnetic resonance imaging during acute ischemic stroke.
abstract: Magnetic resonance (MR) perfusion imaging is a clinical technique for measuring brain blood flow parameters during stroke and other ischemic events. Ischemia in brain tissue can be difficult to accurately measure or visualize when using MR-derived cerebral blood flow (CBF) maps. The deconvolution techniques used to estimate flow can introduce a mean transit time-dependent bias following application of noise stabilization techniques. The underestimation of the CBF values, greatest in normal tissues, causes a decrease in the image contrast observed in CBF maps between normally perfused and ischemic tissues; resulting in ischemic areas becoming less conspicuous. Through application of the proposed simple extrapolation technique, CBF biases are reduced when missing high-frequency signal components in the MR data removed during deconvolution noise stabilization are restored. The extrapolation approach was compared with other methods and showed a statistically significant increase in image contrast in CBF maps between normal and ischemic tissues for white matter (P<.05) and performed better than most other methods for gray matter. Receiver operator characteristic curve analysis demonstrated that extrapolated CBF maps better-detected penumbral regions. Extrapolated CBF maps provided more accurate CBF estimates in simulations, suggesting that the approach may provide a better prediction of outcome in the absence of treatment.
authors.affiliation: Biomedical Engineering, University of Calgary, Alberta, Canada T2N 1N4.
authors.forename: Matthew Ethan
authors.initials: ME
authors.lastname: MacDonald
authors.forename: Michael Richard
authors.initials: MR
authors.lastname: Smith
authors.forename: Richard
authors.initials: R
authors.lastname: Frayne
mesh_terms: D001921:Brain / Q000473:pathology; D002545:Brain Ischemia / Q000473:pathology; D002560:Cerebrovascular Circulation; D003198:Computer Simulation; D003287:Contrast Media / Q000494:pharmacology; D004058:Diffusion; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007511:Ischemia / Q000473:pathology*; D007700:Kinetics; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010477:Perfusion; D012372:ROC Curve; D020521:Stroke / Q000473:pathology*
chemical_list: D003287:Contrast Media