Alpert N M, Buxton R B, Correia J A, Katz P M, Ackerman R H
Department of Radiology, Massachusetts General Hospital, Boston 02114.
J Cereb Blood Flow Metab. 1988 Jun;8(3):403-10. doi: 10.1038/jcbfm.1988.76.
The analysis of positron emission tomography measurements of oxygen metabolism has been extended to provide a quantitative estimate of end-capillary PO2. The principle of this extension rests on the idea that the oxygen extraction fraction can be used to calculate the end-capillary oxygen saturation of the blood. The relation between oxygen saturation and PO2 is obtained through the oxygen dissociation curve. Our studies show that in addition to the local oxygen extraction fraction, arterial PO2 and pH values are needed in the calculation, whereas fairly large variations in factors such as PCO2, hematocrit, hemoglobin, and plasma protein levels have little or no effect. Rough estimates of end-capillary PO2 can be made using standard O2 dissociation nomograms. Blood gas and acid-base properties of blood have been known for decades, making it possible to account accurately for individual differences that may be encountered when studying patients. Measurements in nine normal subjects yielded a mean end-capillary PO2 value of 31.2 mm Hg. The ability to make a quantitative visualization of altered patterns of end-capillary PO2 provides an additional dimension to the investigation of stroke disease and tumor metabolism.
正电子发射断层扫描对氧代谢的测量分析已得到扩展，以提供毛细血管末端氧分压（PO2）的定量估计。这种扩展的原理基于这样一种观点，即氧摄取分数可用于计算血液的毛细血管末端氧饱和度。氧饱和度与PO2之间的关系通过氧解离曲线得出。我们的研究表明，除了局部氧摄取分数外，计算中还需要动脉PO2和pH值，而诸如二氧化碳分压（PCO2）、血细胞比容、血红蛋白和血浆蛋白水平等因素的相当大变化几乎没有影响或没有影响。可以使用标准的氧解离列线图对毛细血管末端PO2进行粗略估计。血液的血气和酸碱特性已为人所知数十年，这使得在研究患者时能够准确考虑可能遇到的个体差异。对9名正常受试者的测量得出毛细血管末端PO2的平均值为31.2毫米汞柱。对毛细血管末端PO2改变模式进行定量可视化的能力为中风疾病和肿瘤代谢的研究提供了一个新的维度。
