title: Comparison of normal tissue R1 and R*2 modulation by oxygen and carbogen.
abstract: Magnetic resonance imaging has shown promise for evaluating tissue oxygenation. In this study differences in the tissue longitudinal relaxation rate (R(1)) and effective transverse relaxation rate (R(*)(2)), induced by inhalation of pure oxygen and carbogen, were evaluated in 10 healthy subjects. Significant reductions in R(1) were demonstrated following both oxygen and carbogen inhalation in the spleen (both P < 0.001), liver (P = 0.002 air vs. oxygen; P = 0.001 air vs. carbogen), skeletal muscle (both P < 0.001), and renal cortex (P = 0.005 air vs. oxygen; P = 0.008 air vs. carbogen). No significant change in R(*)(2) occurred following pure oxygen in any organ. However, a significant increase in R(*)(2) was observed in the spleen (P < 0.001), liver (P = 0.001), skeletal muscle (P = 0.026), and renal cortex (P = 0.001) following carbogen inhalation, an opposite effect to that observed in many studies of tumor pathophysiology. Changes in R(1) and R(*)(2) were independent of the gas administration order in the spleen and skeletal muscle. These findings suggest that the R(1) and R(*)(2) responses to hyperoxic gases are independent biomarkers of oxygen physiology.
authors.affiliation: Imaging Science and Biomedical Engineering, University of Manchester, Manchester, UK. james.o'connor@manchester.ac.uk
authors.forename: James P B
authors.initials: JP
authors.lastname: O'Connor
authors.forename: Josephine H
authors.initials: JH
authors.lastname: Naish
authors.forename: Alan
authors.initials: A
authors.lastname: Jackson
authors.forename: John C
authors.initials: JC
authors.lastname: Waterton
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Watson
authors.forename: Sue
authors.initials: S
authors.lastname: Cheung
authors.forename: David L
authors.initials: DL
authors.lastname: Buckley
authors.forename: Deirdre M
authors.initials: DM
authors.lastname: McGrath
authors.forename: Giovanni A
authors.initials: GA
authors.lastname: Buonaccorsi
authors.forename: Samantha J
authors.initials: SJ
authors.lastname: Mills
authors.forename: Caleb
authors.initials: C
authors.lastname: Roberts
authors.forename: Gordon C
authors.initials: GC
authors.lastname: Jayson
authors.forename: Geoff J M
authors.initials: GJ
authors.lastname: Parker
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000465:Algorithms; D002245:Carbon Dioxide / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008657:Metabolic Clearance Rate; D009928:Organ Specificity; D010100:Oxygen / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D010363:Pattern Recognition, Automated / Q000379:methods*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution
chemical_list: D002245:Carbon Dioxide; C011700:carbogen; D010100:Oxygen