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Organ‐specific effects of oxygen and carbogen gas inhalation on tissue longitudinal relaxation times
Author(s) -
O'Connor James P.B.,
Jackson Alan,
Buonaccorsi Giovanni A.,
Buckley David L.,
Roberts Caleb,
Watson Yvonne,
Cheung Sue,
McGrath Deirdre M.,
Naish Josephine H.,
Rose Chris J.,
Dark Paul M.,
Jayson Gordon C.,
Parker Geoff J.M.
Publication year - 2007
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.21357
Subject(s) - carbogen , inhalation , oxygen , chemistry , kidney , room air distribution , spleen , renal cortex , blood flow , medicine , anesthesia , physics , organic chemistry , thermodynamics
Molecular oxygen has been previously shown to shorten longitudinal relaxation time ( T 1 ) in the spleen and renal cortex, but not in the liver or fat. In this study, the magnitude and temporal evolution of this effect were investigated. Medical air, oxygen, and carbogen (95% oxygen/5% CO 2 ) were administered sequentially in 16 healthy volunteers. T 1 maps were acquired using spoiled gradient echo sequences (TR = 3.5 ms, TE = 0.9 ms, α = 2°/8°/17°) with six acquisitions on air, 12 on oxygen, 12 on carbogen, and six to 12 back on air. Mean T 1 values and change in relaxation rate were compared between each phase of gas inhalation in the liver, spleen, skeletal muscle, renal cortex, and fat by one‐way analysis of variance. Oxygen‐induced T 1 ‐shortening occurred in the liver in fasted subjects ( P < 0.001) but not in non‐fasted subjects ( P = 0.244). T 1 ‐shortening in spleen and renal cortex (both P < 0.001) were greater than previously reported. Carbogen induced conflicting responses in different organs, suggesting a complex relationship with organ vasculature. Shortening of tissue T 1 by oxygen is more pronounced and more complex than previously recognized. The effect may be useful as a biomarker of arterial flow and oxygen delivery to vascular beds. Magn Reson Med 58:490–496, 2007. © 2007 Wiley‐Liss, Inc.