EFFECT OF OXYGEN-TENSION ON NMR SPIN-LATTICE RELAXATION RATE OF BLOOD INVIVO

  • 1 January 1984
    • journal article
    • research article
    • Vol. 19  (3) , 174-178
Abstract
Spin-lattice relaxation rate (1/T1) was measured in the left (LV) and right (RV) ventricular cavities in 4 conscious normal humans and 4 anesthetized greyhound dogs breathing spontaneously. Inspired O2 concentration (F1O2) was varied in 5 steps from 21-100%. In dogs, blood was sampled from indwelling catheters in the pulmonary artery and aorta for measurement of PO2 [partial pressure of O2]. Saturation-recovery and inversion-recovery tomographic images of the ventricular cavities were obtained supine during quiet breathing, using a whole-body NMR scanner operating at a static magnetic field strength of 0.15 Tesla. From F1O2 21-100%, 1/T1 of LV increased by 11.6% in humans and 9.6% in dogs. In dogs, 1/T1 increased by 2.8%/100 mm Hg increase in aortic PO2 (r > 0.87). There was no correlation in dogs between 1/T1 in RV and pulmonary artery PO2. The LV/RV 1/T1 ratio in dogs increased by 4%/100 mm Hg increase in the LV-RV PO2 difference, and by 8% in humans as F1O2 increased from 21 to 100%. A rise in dissolved O2 concentration increases NMR spin-lattice relaxation rates of blood in vivo to a small but signficant extent.

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