背景:脑脊液(CSF)动力学在衰老和神经系统疾病中的研究越来越多。CSF介导的废物清除模型表明,改变的CSF动力学可能在CNS中有毒废物的积累中起作用。与阿尔茨海默病和其他蛋白质病有关。因此,能够对CSF流速进行定量和体积评估的方法可能是有价值的。在这项研究中,我们证明了4D流MRI用于同时评估整个心室系统的CSF动力学的可行性。并评估与动脉搏动的关联,心室容积,和年龄。
方法:在认知未受损的队列中(N=43;年龄41-83岁),在侧脑室(LV)获得心脏分辨4D血流MRICSF速度,门罗的孔眼,第三和第四脑室(V3和V4),脑水管(CA)和椎管(SC),使用5cm/s的速度编码(Venc)。脑血流搏动性也用4D流量(venc=80cm/s)评估,和CSF体积从T1和T2加权MRI获得。多元线性回归用于评估年龄的影响,心室容积,和CSF速度的动脉搏动。
结果:在所有CSF空间中观察到心脏驱动的CSF动力学,区域平均速度范围和均方根(RMS)速度从LV中的非常低(RMS0.25±0.08;范围0.85±0.28mm/s)到CA中的相对较高(RMS6.29±2.87;范围18.6±15.2mm/s)。在回归模型中,5/6地区脑脊液流速与年龄显著相关,到2/3区域的CSF空间体积,以及3/6区域的动脉搏动。组平均波形表明在整个CSF空间中存在明显的CSF流传播延迟,特别是在SC和LV之间。
结论:我们的研究结果表明,4D血流MRI能够评估整个心室系统的脑脊液动力学,捕捉年龄的独立影响,脑脊液空间形态,和脑脊液运动的动脉搏动。
BACKGROUND: Cerebrospinal fluid (CSF) dynamics are increasingly studied in aging and neurological disorders. Models of CSF-mediated waste clearance suggest that altered CSF dynamics could play a role in the accumulation of toxic waste in the CNS, with implications for Alzheimer\'s disease and other proteinopathies. Therefore, approaches that enable quantitative and volumetric assessment of CSF flow velocities could be of value. In this study we demonstrate the feasibility of 4D flow MRI for simultaneous assessment of CSF dynamics throughout the ventricular system, and evaluate associations to arterial pulsatility, ventricular volumes, and age.
METHODS: In a cognitively unimpaired cohort (N = 43; age 41-83 years), cardiac-resolved 4D flow MRI CSF velocities were obtained in the lateral ventricles (LV), foramens of Monro, third and fourth ventricles (V3 and V4), the cerebral aqueduct (CA) and the spinal canal (SC), using a velocity encoding (venc) of 5 cm/s. Cerebral blood flow pulsatility was also assessed with 4D flow (venc = 80 cm/s), and CSF volumes were obtained from T1- and T2-weighted MRI. Multiple linear regression was used to assess effects of age, ventricular volumes, and arterial pulsatility on CSF velocities.
RESULTS: Cardiac-driven CSF dynamics were observed in all CSF spaces, with region-averaged velocity range and root-mean-square (RMS) velocity encompassing from very low in the LVs (RMS 0.25 ± 0.08; range 0.85 ± 0.28 mm/s) to relatively high in the CA (RMS 6.29 ± 2.87; range 18.6 ± 15.2 mm/s). In the regression models, CSF velocity was significantly related to age in 5/6 regions, to CSF space volume in 2/3 regions, and to arterial pulsatility in 3/6 regions. Group-averaged waveforms indicated distinct CSF flow propagation delays throughout CSF spaces, particularly between the SC and LVs.
CONCLUSIONS: Our findings show that 4D flow MRI enables assessment of CSF dynamics throughout the ventricular system, and captures independent effects of age, CSF space morphology, and arterial pulsatility on CSF motion.