Biomedical, Biological, and Chemical Engineering, University of Missouri, Columbia, Missouri.
School of Medicine, University of Missouri, Columbia, Missouri.
Acad Radiol. 2022 Feb;29 Suppl 2:S82-S90. doi: 10.1016/j.acra.2021.01.007. Epub 2021 Jan 21.
In this study, we compared hyperpolarized He and Xe images from patients with cystic fibrosis using two commonly applied magnetic resonance sequences, standard gradient echo (GRE) and balanced steady-state free precession (TrueFISP) to quantify regional similarities and differences in signal distribution and defect analysis.
Ten patients (7M/3F) with cystic fibrosis underwent hyperpolarized gas MR imaging with both He and Xe. Six had MRI with both GRE, and TrueFISP sequences and four patients had only GRE sequence but not TrueFISP. Ventilation defect percentages (VDPs) were calculated as lung voxels with <60% of the whole-lung hyperpolarized gas signal mean and was measured in all datasets. The voxel signal distributions of both Xe and He gases were visualized and compared using violin plots. VDPs of hyperpolarized 3 He and 129 Xe were compared in Bland-Altman plots; Pearson correlation coefficients were used to evaluate the relationships between inter-gas and inter-scan to assess the reproducibility.
A significant correlation was demonstrated between Xe VDP and He VDP for both GRE and TrueFISP sequences (ρ = 0.78, p<0.0004). The correlation between the GRE and TrueFISP VDP for He was ρ = 0.98 and was ρ = 0.91 for Xe. Overall, Xe (27.2±9.4) VDP was higher than He (24.3±6.9) VDP on average on cystic fibrosis patients.
In patients with cystic fibrosis, the selection of hyperpolarized Xe or He gas is most likely inconsequential when it comes to measure the overall lung function by VDP although Xe may be more sensitive to starker lung defects, particularly when using a TrueFISP sequence.
在这项研究中，我们比较了使用两种常用磁共振序列（标准梯度回波（GRE）和平衡稳态自由进动（TrueFISP））获得的囊性纤维化患者的超极化 He 和 Xe 图像，以定量分析信号分布和缺陷分析的区域相似性和差异性。
10 例囊性纤维化患者（7 男/3 女）接受了超极化气体磁共振成像检查，同时使用了 He 和 Xe。其中 6 例患者同时进行了 GRE 和 TrueFISP 序列的 MRI 检查，4 例患者仅进行了 GRE 序列但未进行 TrueFISP 序列检查。通气缺陷百分比（VDP）定义为肺体素中低于整个肺超极化气体信号均值的 60%，并在所有数据集上进行测量。使用小提琴图可视化和比较了 Xe 和 He 气体的体素信号分布。在 Bland-Altman 图中比较了超极化 3 He 和 129 Xe 的 VDP；使用 Pearson 相关系数评估了气体间和扫描间的相关性，以评估可重复性。
对于 GRE 和 TrueFISP 序列，Xe VDP 与 He VDP 之间均显示出显著相关性（ρ=0.78，p<0.0004）。He 的 GRE 和 TrueFISP VDP 之间的相关性为 ρ=0.98，而 Xe 的相关性为 ρ=0.91。总体而言，在囊性纤维化患者中，Xe（27.2±9.4）VDP 平均高于 He（24.3±6.9）VDP。
在囊性纤维化患者中，通过 VDP 测量整体肺功能时，选择超极化 Xe 或 He 气体可能并不重要，尽管 Xe 可能对更明显的肺缺陷更敏感，尤其是在使用 TrueFISP 序列时。
