Liu Thomas T, Brown Gregory G
Department of Radiology, University of California San Diego, San Diego, California 92037, USA.
J Int Neuropsychol Soc. 2007 May;13(3):517-25. doi: 10.1017/S1355617707070646.
Arterial spin labeling (ASL) is a magnetic resonance imaging (MRI) method that provides a highly repeatable quantitative measure of cerebral blood flow (CBF). As compared to the more commonly used blood oxygenation level dependent (BOLD) contrast-based methods, ASL techniques measure a more biologically specific correlate of neural activity, with the potential for more accurate estimation of the location and magnitude of neural function. Recent advances in acquisition and analysis methods have improved the somewhat limited sensitivity of ASL to perfusion changes associated with neural activity. In addition, ASL perfusion measures are insensitive to the low-frequency fluctuations commonly observed in BOLD experiments and can make use of imaging sequences that are less sensitive than BOLD contrast to signal loss caused by magnetic susceptibility effects. ASL measures of perfusion can aid in the interpretation of the BOLD signal change and, when combined with BOLD, can measure the change in oxygen utilization accompanying changes in behavioral state. Whether used alone to probe neural activity or in combination with BOLD techniques, ASL methods are contributing to the field's understanding of healthy and disordered brain function.
动脉自旋标记（ASL）是一种磁共振成像（MRI）方法，可提供对脑血流量（CBF）的高度可重复定量测量。与更常用的基于血氧水平依赖（BOLD）对比的方法相比，ASL技术测量的是神经活动在生物学上更具特异性的相关指标，具有更准确估计神经功能位置和强度的潜力。采集和分析方法的最新进展改善了ASL对与神经活动相关的灌注变化的有限敏感性。此外，ASL灌注测量对BOLD实验中常见的低频波动不敏感，并且可以使用对磁化率效应引起的信号损失比BOLD对比不那么敏感的成像序列。ASL灌注测量有助于解释BOLD信号变化，并且与BOLD结合使用时，可以测量行为状态变化时伴随的氧利用变化。无论是单独用于探测神经活动还是与BOLD技术结合使用，ASL方法都有助于该领域对健康和紊乱脑功能的理解。
