Advanced Imaging Research Center, Oregon Health & Science University, Portland, Oregon, USA.
Montreal Neurological Institute, McGill University, Montréal, Québec, Canada.
J Neuroimaging. 2021 Nov;31(6):1111-1118. doi: 10.1111/jon.12912. Epub 2021 Aug 6.
To compare transcapillary wall water exchange, a putative marker of cerebral metabolic health, in brain T white matter (WM) lesions and normal appearing white and gray matter (NAWM and NAGM, respectively) in individuals with progressive multiple sclerosis (PMS) and healthy controls (HC).
Dynamic-contrast-enhanced 7T MRI data were obtained from 19 HC and 23 PMS participants. High-resolution pharmacokinetic parametric maps representing tissue microvascular and microstructural properties were created by shutter-speed (SS) paradigm modeling to obtain estimates of blood volume fraction (v ), water molecule capillary efflux rate constant (k ), and the water capillary wall permeability surface area product (P S ≡ v *k ). Linear regression models were used to investigate differences in (i) k and P S between groups in NAWM and NAGM, and (ii) between WM lesions and NAWM in PMS.
High-resolution parametric maps were produced to visualize tissue classes and resolve individual WM lesions. Normal-appearing gray matter k and P S were significantly decreased in PMS compared to HC (p ≤ .01). Twenty-one T WM lesions were analyzed in 10 participants with PMS. k was significantly decreased in WM lesions compared to PMS NAWM (p < .0001).
Transcapillary water exchange is reduced in PMS NAGM compared to HC and is further reduced in PMS WM lesions, suggesting pathologically impaired brain metabolism. k provides a sensitive measure of cerebral metabolic activity and/or coupling, and can be mapped at higher spatial resolution than conventional imaging techniques assessing metabolic activity.
比较毛细血管壁水交换，一种潜在的脑代谢健康标志物，在进展性多发性硬化症（PMS）患者的脑白质 T 区（WM）病变与正常表现的白质和灰质（NAWM 和 NAGM）中的差异。
从 19 名健康对照（HC）和 23 名 PMS 参与者中获得了 7T 磁共振成像（MRI）动态对比增强数据。采用快门速度（SS）范式建模，创建高分辨率药代动力学参数图，以获得血容量分数（v）、水分子毛细血管流出率常数（k）和水毛细血管壁渗透性表面积产物（P S≡v*k）的组织微血管和微观结构特性的估计值。线性回归模型用于研究（i）在 NAWM 和 NAGM 中 PMS 组之间和（ii）PMS 中 WM 病变与 NAWM 之间 k 和 P S 的差异。
生成了高分辨率参数图，以可视化组织分类并解析单个 WM 病变。与 HC 相比，PMS 的 NAGM 的 k 和 P S 明显降低（p≤0.01）。在 10 名 PMS 参与者中分析了 21 个 T WM 病变。WM 病变的 k 明显低于 PMS 的 NAWM（p<0.0001）。
与 HC 相比，PMS 的 NAGM 中的跨毛细血管水交换减少，并且在 PMS 的 WM 病变中进一步减少，这表明病理性的脑代谢受损。k 提供了一种敏感的脑代谢活性和/或偶联的测量方法，并且可以比评估代谢活性的常规成像技术以更高的空间分辨率进行映射。
