Division of Radiological Physics, Department of Radiology, University of Basel Hospital, Basel, Switzerland.
Deparment of Biomedical Engineering, University of Basel, Basel, Switzerland.
Magn Reson Med. 2018 Feb;79(2):839-845. doi: 10.1002/mrm.26739. Epub 2017 May 18.
To demonstrate the feasibility of oxygen-dependent relaxometry in human lung using an inversion recovery ultra-fast steady-state free precession (IR-ufSSFP) technique.
Electrocardiogram-triggered pulmonary relaxometry with IR-ufSSFP was performed in 7 healthy human subjects at 1.5 T. The data were acquired under both normoxic and hyperoxic conditions. In a single breath-hold of less than 9 seconds, 30 transient state IR-ufSSFP images were acquired, yielding longitudinal (T1) and transversal (T2) relaxometry parameter maps using voxel-wise nonlinear fitting. Possible spatial misalignments between consecutive IR-ufSSFP parameter maps were corrected using elastic image registration. Furthermore, dynamic relaxometry oxygen wash-in and wash-out scans were performed in one volunteer. From this, T -related wash-in and wash-out time constants (τ , τ ) were calculated voxel-wise on registered maps using an exponential fitting model.
For healthy lung, observed T1 values were 1399 ± 77 and 1290 ± 76 ms under normoxic and hyperoxic conditions, respectively. Oxygen-related reduction of T1 was statistically significant in every volunteer. No statistically significant change, however, was observed in T2, with normoxic and hyperoxic T2 values of 55 ± 16 and 56 ± 17 ms, respectively. The observed average τ was 87.0 ± 28.7 seconds, whereas the average τ was 73.5 ± 21.6 seconds.
IR-ufSSFP allows fast, steady-state, and dynamic oxygen-dependent relaxometry of the human lung. Magn Reson Med 79:839-845, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
利用反转恢复超快稳态自由进动（IR-ufSSFP）技术在人体肺部演示氧依赖弛豫率的可行性。
在 1.5T 下，对 7 名健康志愿者进行了心电图触发的肺部弛豫率测定，采用 IR-ufSSFP 技术。在正常氧合和高氧合两种条件下采集数据。在不到 9 秒的单次屏气中，采集 30 个瞬态 IR-ufSSFP 图像，使用体素非线性拟合得到纵向（T1）和横向（T2）弛豫率参数图。使用弹性图像配准校正连续 IR-ufSSFP 参数图之间可能的空间错位。此外，在一名志愿者中进行了动态弛豫率氧摄取和洗脱扫描。由此，使用指数拟合模型在注册的图谱上对每个体素计算 T 相关的摄取和洗脱时间常数（τ ，τ ）。
对于健康肺，在正常氧合和高氧合条件下，观察到的 T1 值分别为 1399±77 和 1290±76ms。每个志愿者的 T1 与氧相关的降低均具有统计学意义。然而，T2 没有观察到统计学上的显著变化，正常氧合和高氧合的 T2 值分别为 55±16 和 56±17ms。观察到的平均τ为 87.0±28.7 秒，而平均τ为 73.5±21.6 秒。
IR-ufSSFP 允许快速、稳态和动态氧依赖人体肺部弛豫率测定。磁共振医学 79：839-845，2018。© 2017 国际磁共振学会。
