title: Quantitative T1 mapping under precisely controlled graded hyperoxia at 7T.
abstract: Increasing the concentration of oxygen dissolved in water is known to increase the recovery rate (R1 = 1/T1) of longitudinal magnetization (T1 relaxation). Direct T1 changes in response to precise hyperoxic gas challenges have not yet been quantified and the actual effect of increasing arterial oxygen concentration on the T1 of brain parenchyma remains unclear. The aim of this work was to use quantitative T1 mapping to measure tissue T1 changes in response to precisely targeted hyperoxic respiratory challenges ranging from baseline end-tidal oxygen (PetO2) to approximately 500 mmHg. We did not observe measureable T1 changes in either gray matter or white matter parenchymal tissue. The T1 of peripheral cerebrospinal fluid located within the sulci, however, was reduced as a function of PetO2. No significant T1 changes were observed in the ventricular cerebrospinal fluid under hyperoxia. Our results indicate that care should be taken to distinguish actual T1 changes from those which may be related to partial volume effects with cerebrospinal fluid, or regions with increased fluid content such as edema when examining hyperoxia-induced changes in T1 using methods based on T1-weighted imaging.
authors.affiliation: 1 Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Alex A
authors.initials: AA
authors.lastname: Bhogal
authors.affiliation: 1 Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Jeroen Cw
authors.initials: JC
authors.lastname: Siero
authors.affiliation: 1 Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Jaco
authors.initials: J
authors.lastname: Zwanenburg
authors.affiliation: 1 Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Luijten
authors.affiliation: 2 Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Marielle Ep
authors.initials: ME
authors.lastname: Philippens
authors.affiliation: 1 Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Hans
authors.initials: H
authors.lastname: Hoogduin
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D018496:Hyperoxia / Q000134:cerebrospinal fluid / Q000378:metabolism; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010100:Oxygen / Q000008:administration & dosage / Q000378:metabolism*; D010101:Oxygen Consumption; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution
chemical_list: D010100:Oxygen
keywords: Brain imaging; cerebral hemodynamics; cerebrospinal fluid; magnetic resonance imaging; neurophysiology