Bush Adam, Vu Chau, Choi Soyoung, Borzage Matthew, Miao Xin, Li Wenbo, Qin Qin, Nederveen Aart J, Coates Thomas D, Wood John C
Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA.
Department of Radiology, Stanford University, Stanford, California, USA.
Magn Reson Med. 2021 Aug;86(2):1019-1028. doi: 10.1002/mrm.28757. Epub 2021 Mar 14.
Cerebral T oximetry is a non-invasive imaging method to measure blood T and cerebral venous oxygenation. Measured T values are converted to oximetry estimates using carefully validated and potentially disease-specific calibrations. In sickle cell disease, red blood cells have abnormal cell shape and membrane properties that alter T oximetry calibration relationships in clinically meaningful ways. Previous in vitro works by two independent groups established potentially competing calibration models.
This study analyzed pooled datasets from these two studies to establish a unified and more robust sickle-specific calibration to serve as a reference standard in the field.
Even though the combined calibration did not demonstrate statistical superiority compared to previous models, the calibration was unbiased compared to blood-gas co-oximetry and yielded limits of agreement of (-10.1%, 11.6%) in non-transfused subjects with sickle cell disease. In transfused patients, this study proposed a simple correction method based on individual hemoglobin S percentage that demonstrated reduced bias in saturation measurement compared to previous uncorrected sickle calibrations.
The combined calibration is based on a larger range of hematocrit, providing greater confidence in the hematocrit-dependent model parameters, and yielded unbiased estimates to blood-gas co-oximetry measurements from both sites. Additionally, this work also demonstrated the need to correct for transfusion in T oximetry measurements for hyper-transfused sickle cell disease patients and proposes a correction method based on patient-specific hemoglobin S concentration.
脑血氧饱和度测定是一种用于测量血氧饱和度和脑静脉氧合的非侵入性成像方法。使用经过精心验证且可能针对特定疾病的校准方法，将测得的血氧饱和度值转换为血氧饱和度估计值。在镰状细胞病中，红细胞具有异常的细胞形状和膜特性，以具有临床意义的方式改变了血氧饱和度测定的校准关系。此前两个独立研究小组的体外研究建立了可能相互竞争的校准模型。
本研究分析了这两项研究的汇总数据集，以建立一个统一且更稳健的镰状细胞特异性校准方法，作为该领域的参考标准。
尽管与先前模型相比，联合校准未显示出统计学优势，但与血气共血氧测定法相比，该校准无偏差，并且在未输血的镰状细胞病患者中产生的一致性界限为（-10.1%，11.6%）。在输血患者中，本研究提出了一种基于个体血红蛋白S百分比的简单校正方法，与先前未校正的镰状细胞校准相比，该方法在饱和度测量中显示出偏差减小。
联合校准基于更大范围的血细胞比容，为依赖血细胞比容的模型参数提供了更大的可信度，并且对来自两个部位的血气共血氧测定法测量产生了无偏差估计。此外，这项工作还证明了对于大量输血的镰状细胞病患者，在血氧饱和度测定中需要对输血进行校正，并提出了一种基于患者特异性血红蛋白S浓度的校正方法。
