Comparison of quantitative perfusion imaging using arterial spin labeling at 1.5 and 4.0 tesla
Comparison of quantitative perfusion imaging using arterial spin labeling at 1.5 and 4.0 tesla
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DOI：
10.1002/mrm.10211
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发表时间：
2002-08-01
影响因子：
3.3
通讯作者：
Detre, JA
中科院分区：
文献类型：
--
作者：
Wang, JJ;Alsop, DC;Detre, JA
高场动脉自旋标记 (ASL) 灌注 MRI 很有吸引力，因为它不仅提供了更高的信噪比 (SNR)，而且由于标记血液的弛豫时间 T 增加而在标记方面具有优势。在本研究中，我们为 ASL 信号对静态场强的依赖性提供了一个理论框架，随后进行了实验验证，其中在 4T 下进行多层脉冲 ASL (PASL) 技术，并在静息状态和运动激活期间与 1.5T 下的 PASL 和连续 ASL (CASL) 技术进行比较。静息态数据显示，分别使用 4T PASL、1.5T CASL 和 1.5T PASL 获取的差异灌注图像，灰质中的信噪比 (SNR) 为 2.3:1.4:1，灰质和白质之间的对比度噪声比 (CNR) 为 2.7:1.1:1。然而，与 1.5T 功能数据相比，使用 4T PASL 获取的功能数据并未显示出对运动皮层激活的敏感性显着提高，分数灌注信号变化减少，受试者间变异性增加。讨论了这些实验结果的可能原因，包括敏感性效应和生理噪音。
High-field arterial spin labeling (ASL) perfusion MRI is appealing because it provides not only increased signal-to-noise ratio (SNR), but also advantages in terms of labeling due to the increased relaxation time T, of labeled blood. In the present study, we provide a theoretical framework for the dependence of the ASL signal on the static field strength, followed by experimental validation in which a multislice pulsed ASL (PASL) technique was carried out at 4T and compared with PASL and continuous ASL (CASL) techniques at 1.5T, both in the resting state and during motor activation. The resting-state data showed an SNR ratio of 2.3:1.4:1 in the gray matter and a contrast-to-noise ratio (CNR) of 2.7:1.1:1 between the gray and white matter for the difference perfusion images acquired using 4T PASL, 1.5T CASL, and 1.5T PASL, respectively. However, the functional data acquired using 4T PASL did not show significantly improved sensitivity to motor cortex activation compared with the 1.5T functional data, with reduced fractional perfusion signal change and increased intersubject variability. Possible reasons for these experimental results, including susceptibility effects and physiological noise, are discussed.