The Effect of Dissolved Oxygen on the Relaxation Rates of Blood Plasma: Implications for Hyperoxia Calibrated BOLD
The Effect of Dissolved Oxygen on the Relaxation Rates of Blood Plasma: Implications for Hyperoxia Calibrated BOLD
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DOI：
10.1002/mrm.26069
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发表时间：
2016-12-01
影响因子：
3.3
通讯作者：
Pike, G. Bruce
中科院分区：
文献类型：
--
作者：
Ma, Yuhan;Berman, Avery J. L.;Pike, G. Bruce
目的：在高氧校准的BOLD研究中，确定血浆中顺磁溶氧对血氧水平依赖(BOLD)信号变化的贡献。方法：制备牛血浆样品，氧分压(Po(2))为110~600 mm Hg。在3特斯拉条件下，用定量磁共振序列测量溶氧血浆的R-1、R-2和R-2*。结果：血浆中溶解氧的弛豫度为r(1，O2)=1.97+/-0.09×10(-4)S(-1)mm Hg(-1)，r(2，O2)=2.3+/-0.7×10(-4)mm Hg(-1)，r(2，O2)=2.3+/-0.7×10(-4)S(-1)mm Hg(-1)，r(2，O2)=2.3+/-0.7×10(-4)mm Hg(-1)，r(2，O2)=2.3+/-0.7×10(-4)mm Hg(-1)，r(2，O2)=2.3+-0.7×10(-4)mm Hg(-1)。O2)*=2.3+/-0.7x10(-4)S(-1)毫米汞柱(-1)。模拟结果表明，在高氧状态下，溶氧的横向和纵向弛豫速率对BOLD信号均无显著影响。结论：高氧状态下，血浆中溶氧对血液中R-2和R-2*的增加明显小于静脉脱氧血红蛋白对血液中R-2和R-2*的降低。溶解氧对R-1的影响预计也可以忽略不计。因此，动脉中的溶解氧应该不会对高氧校准的BOLD信号有显著影响。(C)2015年国际医学磁共振学会
Purpose: To determine the contribution of paramagnetic dissolved oxygen in blood plasma to blood-oxygenation-level-dependent (BOLD) signal changes in hyperoxic calibrated BOLD studies.Methods: Bovine blood plasma samples were prepared with partial pressures of oxygen (pO(2)) ranging from 110 to 600 mmHg. R-1, R-2, and R-2* of the plasma with dissolved oxygen were measured using quantitative MRI sequences at 3 Tesla. Simulations were performed to predict the relative effects of dissolved oxygen and deoxyhemoglobin changes in hyperoxia calibrated BOLD.Results: The relaxivities of dissolved oxygen in plasma were found to be r(1, O2) = 1.97 +/- 0.09 x 10(-4) s(-1) mmHg(-1), r(2, O2) = 2.3 +/- 0.7 x 10(-4) s(-1) mmHg(-1), and r(2, O2)* = 2.3 +/- 0.7 x 10(-4) s(-1) mmHg(-1). Simulations predict that neither the transverse nor longitudinal relaxation rates of dissolved oxygen contribute significantly to the BOLD signal during hyperoxia.Conclusion: During hyperoxia, the increases in R-2 and R-2* of blood from dissolved oxygen in plasma are considerably less than the decreases in R-2 and R-2* from venous deoxyhemoglobin. R-1 effects due to dissolved oxygen are also predicted to be negligible. As a result, dissolved oxygen in arteries should not contribute significantly to the hyperoxic calibrated BOLD signal. (C) 2015 International Society for Magnetic Resonance in Medicine