Department of Biomedical Engineering, University of Southern California, Los Angeles, California.
Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, California.
Magn Reson Med. 2019 Dec;82(6):2188-2198. doi: 10.1002/mrm.27871. Epub 2019 Jun 27.
To investigate the mutual agreement of T2-based and susceptibility-based methods as well as their agreement with jugular catheterization, for quantifying venous oxygen saturation (S O ) at a broad range of brain oxygenation levels.
S O measurements using T2-relaxation-under-spin-tagging (TRUST) and susceptibility-based oximetry (SBO) were performed in 13 healthy subjects under room air, hypoxia, and hypercapnia conditions. Agreement between TRUST and SBO was quantitatively evaluated. In two of the subjects, TRUST and SBO were compared against the clinical gold standard, co-oximeter measurement via internal jugular vein catheterization.
Absolute S O measurements using TRUST and SBO were highly correlated across a range of saturations from 45% to 84% (Pearson r = 0.91, P < .0001). S O -TRUST was significantly lower than S O -SBO under hypoxia and room air conditions, but the two were comparable under hypercapnia. TRUST demonstrated a larger S O increase under hypercapnia than SBO and had good agreement with jugular catheterization under hypercapnia but significantly underestimated S O under room air and hypoxia. The agreement between S O -SBO and the reference did not depend on the physiological state.
A systematic bias was observed between T2-based and susceptibility-based methods that depended on the oxygenation state. In vivo validation with jugular catheterization indicated potential underestimation of TRUST under room air and hypoxia conditions. Our findings suggested that caution should be employed in comparison of absolute S O measurements using either TRUST or SBO.
研究 T2 基础法和磁化率基础法之间的相互一致性，以及它们与颈内静脉导管测量在广泛的脑氧合水平下量化静脉血氧饱和度（S O ）的一致性。
在 13 名健康受试者在空气、低氧和高碳酸血症条件下进行 T2 弛豫标记（TRUST）和磁化率基础血氧测量（SBO）。定量评估 TRUST 和 SBO 之间的一致性。在其中两名受试者中，将 TRUST 和 SBO 与临床金标准（通过颈内静脉导管进行的内部 co-oximeter 测量）进行比较。
在 45%至 84%的饱和度范围内，使用 TRUST 和 SBO 的绝对 S O 测量值高度相关（Pearson r = 0.91，P <.0001）。在低氧和空气条件下，S O -TRUST 明显低于 S O -SBO，但在高碳酸血症条件下两者相当。TRUST 在高碳酸血症下显示出比 SBO 更大的 S O 增加，与颈内静脉导管测量具有良好的一致性，但在空气和低氧条件下明显低估了 S O 。S O -SBO 与参考值的一致性不依赖于生理状态。
在基于 T2 和基于磁化率的方法之间观察到了与氧合状态相关的系统偏差。颈内静脉导管的体内验证表明，TRUST 在空气和低氧条件下可能存在低估。我们的研究结果表明，在比较使用 TRUST 或 SBO 的绝对 S O 测量值时应谨慎。
