Janne d'Othée Bertrand, Rachmuth Guy, Munasinghe Jeeva, Lang Elvira V
Department of Radiology - W/CC 335, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215-5400, USA.
Acad Radiol. 2003 Aug;10(8):854-60. doi: 10.1016/s1076-6332(03)00004-7.
Ventilation with high oxygen (O2) concentrations has been shown to decrease T1 in blood and tissues of patients. This study aims to assess the effect of hyperoxygenation on the T1 relaxation time of blood and other physiologic solutions.
Varied gaseous mixtures of O2 and air between 21% and 100% O2 were created using an experimental circuit at room temperature, and used to saturate human blood, plasma, or normal saline. The samples were studied using an 8.45-Tesla magnetic resonance (MR) system and a 1.5-Tesla clinical MR scanner.
MR spectroscopy at 8.45 Tesla showed that the percentage of O2 chosen for saturation correlated negatively with T1 (R2 = 1.00 for blood, 0.99 for plasma, and 1.00 for normal saline). The reduction in T1 between solutions saturated with 21% and 100% O2 was 487 milliseconds (22% of the baseline T1 value) for blood, 391 milliseconds (15%) for plasma and 622 milliseconds (19%) for saline. Similarly, MR measurements at 1.5 Tesla showed T1 reduction with increasing O2 concentration. Conclusion. The decreasing T1 in blood depends strongly on the fraction of dissolved O2 in solution and is largely independent of the hemoglobin content.
已证实高氧（O₂）浓度通气可使患者血液和组织中的T1缩短。本研究旨在评估高氧对血液及其他生理溶液T1弛豫时间的影响。
在室温下使用实验回路制备含氧量在21%至100%之间的不同O₂与空气混合气体，并用其使人体血液、血浆或生理盐水饱和。使用8.45特斯拉磁共振（MR）系统和1.5特斯拉临床MR扫描仪对样本进行研究。
8.45特斯拉的磁共振波谱显示，用于饱和的O₂百分比与T1呈负相关（血液的R² = 1.00，血浆的R² = 0.99，生理盐水的R² = 1.00）。对于血液，用21%和100% O₂饱和的溶液之间T1缩短了487毫秒（为基线T1值的22%），血浆缩短了391毫秒（15%），生理盐水缩短了622毫秒（19%）。同样，1.5特斯拉的MR测量显示随着O₂浓度增加T1缩短。结论：血液中T1的缩短很大程度上取决于溶液中溶解O₂的比例，且在很大程度上与血红蛋白含量无关。
