Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, United Kingdom.
Wolfson Wohl Translational Cancer Research Center, Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom.
Magn Reson Med. 2018 Feb;79(2):1020-1030. doi: 10.1002/mrm.26706. Epub 2017 May 17.
A systematic method is proposed for optimizing a promising preclinical arterial spin labeling (ASL) sequence based on the use of a train of adiabatic radiofrequency pulses labeling successive boli of blood water.
The sequence optimization is performed and evaluated using brain imaging experiments in mice and in rats. It involves the investigation of several parameters, ranging from the number of adiabatic pulses and labeling duration to the properties of the adiabatic hyperbolic secant pulses (ie, amplitude and frequency modulation).
Species-dependent parameters are identified, allowing for robust fast optimization protocols to be introduced. The resulting optimized multiple boli ASL (mbASL) sequence provides with significantly higher average signal-to-noise ratios (SNR) per voxel volume than currently encountered in ASL studies (278 mm in mice and 172 mm in rats). Comparing with the commonly used flow-sensitive alternating inversion recovery technique (FAIR), mbASL-to-FAIR SNR ratios reach 203% for mice and 725% for rats.
When properly optimized, mbASL can offer a robust, high SNR ASL alternative for rodent brain perfusion studies Magn Reson Med 79:1020-1030, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
提出了一种基于使用一系列绝热射频脉冲标记连续血水质子的系统方法，用于优化有前途的临床前动脉自旋标记（ASL）序列。
使用小鼠和大鼠的脑成像实验对序列优化进行了研究和评估。它涉及对几个参数的研究，从绝热脉冲的数量和标记持续时间到绝热双曲线正割脉冲的特性（即幅度和频率调制）。
确定了与物种相关的参数，允许引入稳健的快速优化协议。所得优化的多 bolus ASL（mbASL）序列提供了比目前在 ASL 研究中遇到的更高的每个体素体积的平均信噪比（SNR）（小鼠为 278mm，大鼠为 172mm）。与常用的流动敏感交替反转恢复技术（FAIR）相比，mbASL 与 FAIR 的 SNR 比值在小鼠中达到 203%，在大鼠中达到 725%。
当适当优化时，mbASL 可以为啮齿动物脑灌注研究提供一种稳健、高 SNR 的 ASL 替代方法。磁共振医学 79：1020-1030，2018。© 2017 国际磁共振学会。
