Hirschler Lydiane, Munting Leon P, Khmelinskii Artem, Teeuwisse Wouter M, Suidgeest Ernst, Warnking Jan M, van der Weerd Louise, Barbier Emmanuel L, van Osch Matthias J P
Université Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.
Inserm, U1216, Grenoble, France.
NMR Biomed. 2018 Feb;31(2). doi: 10.1002/nbm.3855. Epub 2017 Nov 21.
The cerebral blood flow (CBF) is a potential biomarker for neurological disease. However, the arterial transit time (ATT) of the labeled blood is known to potentially affect CBF quantification. Furthermore, ATT could be an interesting biomarker in itself, as it may reflect underlying macro- and microvascular pathologies. Currently, no optimized magnetic resonance imaging (MRI) sequence exists to measure ATT in mice. Recently, time-encoded labeling schemes have been implemented in rats and humans, enabling ATT mapping with higher signal-to-noise ratio (SNR) and shorter scan time than multi-delay arterial spin labeling (ASL). In this study, we show that time-encoded pseudo-continuous arterial spin labeling (te-pCASL) also enables transit time measurements in mice. As an optimal design that takes the fast blood flow in mice into account, time encoding with 11 sub-boli of 50 ms is proposed to accurately probe the inflow of labeled blood. For perfusion imaging, a separate, traditional pCASL scan was employed. From the six studied brain regions, the hippocampus showed the shortest ATT (169 ± 11 ms) and the auditory/visual cortex showed the longest (284 ± 16 ms). Furthermore, ATT was found to be preserved in old wild-type mice. In a mouse with an induced carotid artery occlusion, prolongation of ATT was shown. In conclusion, this study shows the successful implementation of te-pCASL in mice, making it possible, for the first time, to measure ATT in mice in a time-efficient manner.
脑血流量（CBF）是神经疾病的一种潜在生物标志物。然而，已知标记血液的动脉通过时间（ATT）可能会影响CBF的定量。此外，ATT本身可能是一个有趣的生物标志物，因为它可能反映潜在的大血管和微血管病变。目前，尚无优化的磁共振成像（MRI）序列可用于测量小鼠的ATT。最近，时间编码标记方案已在大鼠和人类中实施，与多延迟动脉自旋标记（ASL）相比，能够以更高的信噪比（SNR）和更短的扫描时间进行ATT映射。在本研究中，我们表明时间编码伪连续动脉自旋标记（te-pCASL）也能够在小鼠中进行通过时间测量。作为一种考虑到小鼠快速血流的优化设计，建议采用11个50毫秒子团注的时间编码来准确探测标记血液的流入。对于灌注成像，采用了单独的传统pCASL扫描。在所研究的六个脑区中，海马体的ATT最短（169±11毫秒），听觉/视觉皮层的最长（284±16毫秒）。此外，发现老年野生型小鼠的ATT保持不变。在一只诱导颈动脉闭塞的小鼠中，显示出ATT延长。总之，本研究表明te-pCASL在小鼠中成功实施，首次使得以高效的方式测量小鼠的ATT成为可能。
