Department of Radiology and Nuclear Medicine, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing 100053, China.
Department of Radiology and Nuclear Medicine, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing 100053, China.
Brain Res. 2025 Jan 1;1846:149259. doi: 10.1016/j.brainres.2024.149259. Epub 2024 Oct 3.
The oxygen extraction fraction is an essential biomarker for the assessment of brain metabolism. A recently proposed method combined with quantitative susceptibility mapping and quantitative blood oxygen level-dependent magnitude enables noninvasive mapping of the oxygen extraction fraction. Our study investigated the oxygen extraction fraction mapping variations of single-delay and multi-delay arterial spin-labeling.
A total of twenty healthy participants were enrolled. The multi-echo spoiled gradient-echo, multi-delay arterial spin-labeling, and magnetization-prepared rapid gradient echo sequences were acquired at 3.0 T. The mean oxygen extraction fraction was generated under a single delay time of 1780 ms, multi-delay arterial spin-labeling of transit-corrected cerebral blood flow, and multi-delay arterial spin-labeling of arterial cerebral blood volume. The results were compared via paired t tests and the Wilcoxon test. Linear regression analyses were used to investigate the relationships among the oxygen extraction fraction, cerebral blood flow, and venous cerebral blood volume.
The oxygen extraction fraction estimate with multi-delay arterial spin-labeling yielded a significantly lower value than that with single-delay arterial spin-labeling. The average values for the whole brain under single-delay arterial spin-labeling, multi-delay arterial spin-labeling of transit-corrected cerebral blood flow, and multi-delay arterial spin-labeling of arterial cerebral blood volume were 41.5 ± 1.7 % (P < 0.05), 41.3 ± 1.9 % (P < 0.001), and 40.9 ± 1.9 % (N = 20), respectively. The oxygen extraction fraction also showed a significant inverse correlation with the venous cerebral blood volume under steady-state conditions when multi-delay arterial spin-labeling was used (r = 0.5834, p = 0.0069).
These findings suggest that the oxygen extraction fraction is significantly impacted by the arterial spin-labeling methods used in the quantitative susceptibility mapping plus the quantitative blood oxygen level-dependent model, indicating that the differences should be accounted for when employing oxygen extraction fraction mapping based on this model in diseases.
氧摄取分数是评估脑代谢的重要生物标志物。一种新提出的方法，结合定量磁化率图和定量血氧水平依赖幅度图，可实现氧摄取分数的无创性映射。本研究探讨了单延迟和多延迟动脉自旋标记的氧摄取分数映射变化。
共纳入 20 名健康志愿者。在 3.0T 上采集多回波扰相梯度回波、多延迟动脉自旋标记和磁化准备快速梯度回波序列。在单延迟时间为 1780ms 下生成平均氧摄取分数，多延迟动脉自旋标记的转铁校正脑血流和多延迟动脉自旋标记的动脉脑血容量。通过配对 t 检验和 Wilcoxon 检验比较结果。线性回归分析用于研究氧摄取分数、脑血流和静脉脑血容量之间的关系。
多延迟动脉自旋标记的氧摄取分数估计值明显低于单延迟动脉自旋标记。单延迟动脉自旋标记、多延迟动脉自旋标记的转铁校正脑血流和多延迟动脉自旋标记的动脉脑血容量下全脑的平均数值分别为 41.5±1.7%（P<0.05）、41.3±1.9%（P<0.001）和 40.9±1.9%（N=20）。当使用多延迟动脉自旋标记时，氧摄取分数与稳态下的静脉脑血容量呈显著负相关（r=0.5834，p=0.0069）。
这些发现表明，氧摄取分数受到定量磁化率图加定量血氧水平依赖模型中使用的动脉自旋标记方法的显著影响，这表明在基于该模型的疾病氧摄取分数映射中应考虑这些差异。
