title: A general model to calculate the spin-lattice (T1) relaxation time of blood, accounting for haematocrit, oxygen saturation and magnetic field strength.
abstract: Many MRI techniques require prior knowledge of the T1-relaxation time of blood (T1bl). An assumed/fixed value is often used; however, T1bl is sensitive to magnetic field (B0), haematocrit (Hct), and oxygen saturation (Y). We aimed to combine data from previous in vitro measurements into a mathematical model, to estimate T1bl as a function of B0, Hct, and Y. The model was shown to predict T1bl from in vivo studies with a good accuracy (± 87 ms). This model allows for improved estimation of T1bl between 1.5-7.0 T while accounting for variations in Hct and Y, leading to improved accuracy of MRI-derived perfusion measurements.
authors.affiliation: Developmental Imaging and Biophysics Section, Institute of Child Health, University College London, London, UK p.hales@ucl.ac.uk.
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Hales
authors.affiliation: Clinical Neurosciences Section, Institute of Child Health, University College London, London, UK.
authors.forename: Fenella J
authors.initials: FJ
authors.lastname: Kirkham
authors.affiliation: Developmental Imaging and Biophysics Section, Institute of Child Health, University College London, London, UK.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Clark
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D000818:Animals; D002417:Cattle; D002648:Child; D003627:Data Interpretation, Statistical; D004574:Electromagnetic Fields; D006400:Hematocrit; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods* / Q000706:statistics & numerical data*; D018810:Magnetic Resonance Angiography / Q000379:methods* / Q000706:statistics & numerical data*; D008875:Middle Aged; D008959:Models, Neurological; D008962:Models, Theoretical; D009010:Monte Carlo Method; D010100:Oxygen / Q000097:blood*; D015203:Reproducibility of Results; D013113:Spin Labels; D055815:Young Adult
chemical_list: D013113:Spin Labels; D010100:Oxygen
keywords: ASL; MRI; cerebral blood flow measurement; mathematical modelling; perfusion weighted MRI