Comparison of normal tissue R1 and R*2 modulation by oxygen and carbogen.
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.
O'Connor
James P B
JP
Imaging Science and Biomedical Engineering, University of Manchester, Manchester, UK. james.o'connor@manchester.ac.uk
Naish
Josephine H
JH
Jackson
Alan
A
Waterton
John C
JC
Watson
Yvonne
Y
Cheung
Sue
S
Buckley
David L
DL
McGrath
Deirdre M
DM
Buonaccorsi
Giovanni A
GA
Mills
Samantha J
SJ
Roberts
Caleb
C
Jayson
Gordon C
GC
Parker
Geoff J M
GJ
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
D002245:Carbon Dioxide; C011700:carbogen; D010100:Oxygen