A two-stage approach for measuring vascular water exchange and arterial transit time by diffusion-weighted perfusion MRI.
A two-stage approach for measuring vascular water exchange and arterial transit time by diffusion-weighted perfusion MRI.
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DOI：
10.1002/mrm.23104
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发表时间：
2012-05
影响因子：
3.3
通讯作者：
Wang, Danny J. J.
中科院分区：
文献类型：
--
作者：
St Lawrence, Keith S.;Owen, Daron;Wang, Danny J. J.
水穿过血脑屏障（BBB）的交换速率（表示为kw）的变化可能表明在可观察到大分子造影剂泄漏之前BBB功能障碍。先前提出的用于测量kw的方法是使用扩散加权（DW）动脉自旋标记（ASL）来测量标记水的血管和组织分数，因为血管-组织比与kw相关。然而，DW-ASL的准确性受到动脉血液贡献和动脉通过时间（τa）的影响。为了解决这些问题，提出了一种两阶段方法，该方法使用DW梯度强度和后标记延迟的组合来测量τa和kw。通过采集7名健康志愿者的DW-ASL数据，评估了该方法的可行性。进行重复测量和蒙特卡罗模拟，以确定kw估计值的精度和准确度。平均灰质和白色物质kw值分别为110 ± 18和126 ± 18 min-1，与正电子发射断层扫描获得的BBB渗透性测量结果相比，这是有利的。灰质和白色物质的受试者内变异系数分别为26 ± 23%和21 ± 17%，表明可以获得可重复的kw测量值。
Changes in the exchange rate of water across the blood-brain barrier (BBB), denoted kw, may indicate BBB dysfunction before the leakage of large-molecule contrast agents is observable. A previously proposed approach for measuring kw is to use diffusion-weighted (DW) arterial spin labeling (ASL) to measure the vascular and tissue fractions of labeled water, since the vascular-to-tissue ratio is related to kw. However, the accuracy of DW-ASL is affected by arterial blood contributions and the arterial transit time (τa). To address these issues, a two-stage method is proposed that uses combinations of DW gradient strengths and post-labeling delays to measure both τa and kw. The feasibility of this method was assessed by acquiring DW-ASL data from 7 healthy volunteers. Repeat measurements and Monte Carlo simulations were conducted to determine the precision and accuracy of the kw estimates. Average grey and white matter kw values were 110 ± 18 and 126 ± 18 min−1, respectively, which compare favorably to BBB permeability measurements obtained with positron emission tomography. The intra-subject coefficient of variation was 26 ± 23% in grey matter and 21 ± 17% in white matter, indicating that reproducible kw measurements can be obtained.
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影响因子：
3.3
作者：
DIXON, WT;SARDASHTI, M;STOMP, GP
通讯作者：
STOMP, GP
影响因子：
6.3
作者：
PARDRIDGE, WM;FIERER, G
通讯作者：
FIERER, G
影响因子：
2.9
作者：
PAWLIK, G;RACKL, A;BING, RJ
通讯作者：
BING, RJ
影响因子：
3.3
作者：
Ewing, JR;Cao, Y;Fenstermacher, J
通讯作者：
Fenstermacher, J
DOI：
10.1097/00004647-199611000-00019
发表时间：
1996-11-01
影响因子：
6.3
作者：
Alsop, DC;Detre, JA
通讯作者：
Detre, JA