在实验性缺氧期间，对3T磁场下胎羊大脑进行的血氧水平依赖性功能磁共振成像（BOLD MRI）。
BOLD MRI in the brain of fetal sheep at 3T during experimental hypoxia.
作者信息
Schoennagel Bjoern P, Yamamura Jin, Fischer Roland, Tavares de Sousa Manuela, Weyhmiller Marcela, Birkelbach Moritz, Kooijman Hendrik, Adam Gerhard, Wedegaertner Ulrike
机构信息
Department of Diagnostic and Interventional Radiology, University Medical Center, Hamburg-Eppendorf, Hamburg, Germany.
出版信息
J Magn Reson Imaging. 2015 Jan;41(1):110-6. doi: 10.1002/jmri.24555. Epub 2013 Dec 18.
PURPOSE
To calculate regional fetal brain oxygen saturation (sO2) during hypoxia in sheep.
MATERIALS AND METHODS
Eight pregnant ewes were examined at a 3T MR-scanner using blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) to measure signal intensity changes of the fetal brain during a control period and a period of induced hypoxia. Regions of interest were placed in the fetal cerebrum to assess ΔR2* from GRE signal intensity plateaus (S(control), S(hypoxia)) and the relation between ΔR2* and ΔpO2 was analyzed. A probe was placed surgically in the fetal brain to directly measure local pO2 as a reference standard. Baseline and hypoxic pO2 values were recorded and compared (ΔpO2).
RESULTS
Mean fetal brain pO2 decreased from 14.3 mmHg (95% confidence interval [CI]: 10-19) to 3.4 mmHg (95% CI: 2-5) during hypoxia (mean ΔpO2 = 10.9 mmHg and ΔR2* = -5s(-1)). A significant correlation between ΔR2* and ΔpO2 was noted (r = 0.93, P < 0.001), and conversion of pO2 into sO2 resulted in a linear regression coefficient of (-0.14 ± 0.01)s(-1)/% (r(2) = 0.91).
CONCLUSION
Measured fetal brain BOLD-MRI was compared and converted to pO2, followed by calculation of cerebral sO2.
目的
计算绵羊缺氧期间胎儿脑区的氧饱和度（sO2）。
材料与方法
对8只怀孕母羊在3T磁共振扫描仪上进行检查，使用血氧水平依赖性功能磁共振成像（BOLD-MRI）测量胎儿脑在对照期和诱导缺氧期的信号强度变化。在胎儿大脑中放置感兴趣区域，以评估来自梯度回波信号强度平台（S(对照)，S(缺氧)）的ΔR2*，并分析ΔR2*与ΔpO2之间的关系。通过手术将一个探头放置在胎儿脑中，直接测量局部pO2作为参考标准。记录并比较基线和缺氧时的pO2值（ΔpO2）。
结果
缺氧期间，胎儿脑平均pO2从14.3 mmHg（95%置信区间[CI]：10 - 19）降至3.4 mmHg（95% CI：2 - 5）（平均ΔpO2 = 10.9 mmHg，ΔR2* = -5s(-1)）。观察到ΔR2*与ΔpO2之间存在显著相关性（r = 0.93，P < 0.001），将pO2转换为sO2得到线性回归系数为(-0.14 ± 0.01)s(-1)/%（r(2) = 0.91）。
结论
对测量的胎儿脑BOLD-MRI进行比较并转换为pO2，随后计算脑sO2。
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