Objective

To determine the feasibility of 3D TGSE PASL MRI with long inversion times to estimate CNS perfusion clearance, comparing normals to Alzheimer disease patients.

Methods

This pilot study used 3D TGSE PASL MRI with long TIs to estimate the signal clearance of labeled blood/ultra-filtrate (CSF) from brain signal averages of seven inversion times (TI) from six regions of the brain in 18 normal subjects of ages 18–70 years before and after exercise. Arterial pulse corrected signal average per TI versus TI was plotted. The slope (linear regression) indicated the clearance rate. Three subjects with mild Alzheimer disease (AD) were studied pre-exercise only.

Results

In normals, signal decay rate variance among brain regions, age groups and post-exercise failed to demonstrate statistical significance except in middle-age group pre- to post-exercise-dominant temporal lobe. We found highly statistically significant reduced signal clearance rate in the AD group.

Discussion

Signal decay in normal age groups correlates with decay of T1_blood, thus CSF paravascular flow egresses and is inseparable from venous outflow. The AD group correlates with decay rate T1_CSF, indicating a proportion of labeled blood ultra-filtered within the brain (paravascular fluid) is retained. This provides indirect evidence of reduced paravascular clearance in AD. Further development may produce an efficient biomarker identifying neurodegenerative diseases and future treatment efficacy.

中文翻译：

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利用MRI 3D TGSE PASL（动脉旋转标记）进行的先导研究可区分早期阿尔茨海默病患者与正常受试者中枢神经系统中标记质子的清除率。

目的

为了确定3D TGSE PASL MRI具有长反演时间以评估CNS灌注清除率的可行性，将正常人与阿尔茨海默病患者进行比较。

方法

这项前瞻性研究将3D TGSE PASL MRI与长TI结合使用，以从18个18岁正常受试者的大脑六个区域的七个倒置时间（TI）的大脑平均信号估计标记的血液/超滤液（CSF）的信号清除–运动前后70年。绘制了每个TI对TI的经动脉脉冲校正的信号平均值。斜率（线性回归）表示清除率。仅在运动前研究了三名患有轻度阿尔茨海默病（AD）的受试者。

结果

在正常人中，除了在运动后占主导的颞叶的中年组外，大脑区域，年龄组和运动后之间的信号衰减率方差均未显示出统计学意义。我们发现AD组的信号清除率在统计学上有显着降低。

讨论区

正常年龄组的信号衰减与T1_血液的衰减相关，因此CSF血管旁血流流出，与静脉流出密不可分。AD组与衰变率T1 _CSF相关，表明保留了在大脑内超滤的一部分标记血液（血管旁液）。这提供了减少AD中血管旁清除率的间接证据。进一步的发展可能产生识别神经退行性疾病和未来治疗功效的有效生物标志物。