Evaluation of systematic quantification errors in velocity-selective arterial spin labeling of the brain
Evaluation of systematic quantification errors in velocity-selective arterial spin labeling of the brain
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DOI：
10.1002/mrm.10510
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发表时间：
2003-07-01
影响因子：
3.3
通讯作者：
Alsop, DC
中科院分区：
文献类型：
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作者：
Duhamel, G;de Bazelaire, U;Alsop, DC
速度选择性（VS）序列可能会允许使用非常接近组织的标记的动脉自旋标记（ASL）灌注成像。在这项研究中，评估了脑脊液（CSF）运动，射频（RF）场缺陷的影响以及序列时正式参数对使用VS-ASL获得的外观和定量灌注值的影响。观察到与CSF运动相关的大型伪像，以中等速度的加权观察到，这些伪像，以增加成像时间的成本为代价，通过反转恢复制备来清除。由不均匀的RF场引起的不完善的重新聚焦和激发脉冲在ASL减法图像中产生了系统误差。引入了相位循环方案，以消除这些错误。通过CSF抑制和相循环获得定量灌注图像。测量了27.7 ml 100 g（-1）分钟（-1）的灰质血流，大约是使用空间选择性ASL的研究中报告的值的一半。讨论了这种低估的潜在来源。 （c）2003 Wiley-Liss，Inc。
Velocity-selective (VS) sequences potentially permit arterial spin labeling (ASL) perfusion imaging with labeling applied very close to the tissue. In this study the effects of cerebrospinal fluid (CSF) motion, radiofrequency (RF) field imperfections, and sequence timing parameters on the appearance and quantitative perfusion values obtained with VS-ASL were evaluated. Large artifacts related to CSF motion were observed with moderate velocity weighting, which were removed by inversion recovery preparation at the cost of increased imaging time. Imperfect refocusing and excitation pulses resulting from nonuniform RF fields produced systematic errors in the ASL subtraction images. A phase cycling scheme was introduced to eliminate these errors. Quantitative perfusion images were obtained with CSF suppression and phase cycling. Gray matter blood flow of 27.7 ml 100 g(-1) min(-1), approximately half the value reported in studies using spatially-selective ASL, was measured. Potential sources for this underestimation are discussed. (C) 2003 Wiley-Liss, Inc.