Purpose: Oxygen-17 (17O) MRS imaging, successfully used in the brain, is extended by imaging the oxygen metabolic rate in the resting skeletal muscle and used to determine the total whole-body oxygen metabolic rate in the rat. Methods: During and after inhalations of 17O2 gas, dynamic 17O MRSI was performed in rats (n = 8) ventilated with N2O or N2 at 16.4 T. Time courses of the H217O concentration from regions of interest located in brain and muscle tissue were examined and used to fit an animal-adapted 3-phase metabolic model of oxygen consumption. CBF was determined with an independent washout method. Finally, body oxygen metabolic rate was calculated using a global steady-state approach. Results: Cerebral metabolic rate of oxygen consumption was 1.97 ± 0.19 μmol/g/min on average. The resting metabolic rate of oxygen consumption in skeletal muscle was 0.32 ± 0.12 μmol/g/min and >6 times lower than cerebral metabolic rate of oxygen consumption. Global oxygen consumed by the body was 24.2 ± 3.6 mL O2/kg body weight/min. CBF was estimated to be 0.28 ± 0.02 mL/g/min and 0.34 ± 0.06 mL/g/min for the N2 and N2O ventilation condition, respectively. Conclusion: We have evaluated the feasibility of 17O MRSI for imaging and quantifying the oxygen consumption rate in low metabolizing organs such as the skeletal muscle at rest. Additionally, we have shown that CBF is slightly increased in the case of ventilation with N2O. We expect this study to be beneficial to the application of 17O MRSI to a wider range of organs, although further validation is advised.
Bibliographical noteFunding Information:
The study was sponsored by the Max Planck Society and in part by the NIH grants: R01 NS070839, R01 MH111413, R01 CA240953, U01 EB026978, and P41 EB027061 and by the Institute for Basic Science, Suwon, Republic of South Korea (IBS‐R015‐D1) to Kâmil Uludağ. Open access funding enabled and organized by Projekt DEAL.
The study was sponsored by the Max Planck Society and in part by the National Institutes of Health (NIH) grants: R01 NS070839, R01 MH111413, R01 CA240953, U01 EB026978, and P41 EB027061; and by the Institute for Basic Science, Suwon, Republic of South Korea (IBS‐R015‐D1) to Kâmil Uludağ
© 2020 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine
- O MRSI of HO
- cerebral blood flow (CBF)
- cerebral metabolic rate of oxygen (CMRO)
- mitochondrial water
- muscle resting metabolic rate of oxygen consumption
- skeletal muscle metabolism
- total body oxygen consumption (VO)