Hu Ying, Lv Fajin, Li Qi, Liu Rongbo
Department of Radiology, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu, Sichuan.
Department of Radiology.
Medicine (Baltimore). 2020 Jul 2;99(27):e20463. doi: 10.1097/MD.0000000000020463.
Investigating the effect of post-labeling delay (PLD) on regional cerebral blood flow (CBF) in adults and optimizing the PLD for arterial spin-labeling (ASL) magnetic resonance (MR) imaging are important.
Pseudo-continuous ASL imaging with a three PLDs protocol was performed in 90 healthy adult volunteers from January 2018 to February 2019. Healthy subjects were divided into youth group (mean age, 30.63 years; age range, 20-44 years), middle-aged group (mean age, 52.16 years; age range 45-59 years) and elderly group (mean age, 66.07 years; age range, 60-77 years). After preprocessing, analyses of variance (ANOVA) and volume-of-interest (VOI) were conducted to compare the CBF in each brain region. According to the trends of CBF changing with PLD and the results of ANOVA, we optimized the PLD for ASL imaging in different brain regions and age groups.
The CBF values of 87 VOIs [global gray matter (global GM) and other 86 VOIs] for each subject were obtained. Young people had less statistically significant VOIs than middle-aged and elderly people [Numbers of VOIs which had statistical significance (P < .05) in the analysis of ANOVA: 42 (youth group), 79 (middle-aged group), and 71 (elderly group)]. In youth group, the deep GM, occipital lobe and temporal lobe were more affected by PLDs than limbic system, frontal lobe and parietal lobe [VOIs with statistical significance (P < .05)/total VOIs: 8/8 (deep GM) > 8/12 (occipital lobe) > (8/14) (temporal lobe) > 5/12 (limbic system) > 11/28 (frontal lobe) > (2/12) parietal lobe]. In middle-aged group, the limbic system, deep GM and temporal lobe were more affected by PLDs than parietal lobe, frontal lobe and occipital lobe [VOIs with statistical significance (P < 0.05)/total VOIs: 12/12 (limbic system) = 8/8 (deep GM) > (13/14) (temporal lobe) > (11/12) parietal lobe > 25/28 (frontal lobe) > 9/12 (occipital lobe)]. In elderly group, the temporal lobe, parietal lobe, and frontal lobe were more affected by PLDs than occipital lobe, limbic system, and deep GM [VOIs with statistical significance (P < .05)/total VOIs: 14/14 (temporal lobe) > 12/12 (parietal lobe) > 22/28 (frontal lobe) > 9/12 (occipital lobe) > 8/12 (limbic system) > 5/8 (deep GM)]. The optimal PLD for most VOIs in youth group was 1525 ms. However, for middle-aged and elderly group, the optimal PLD for most VOIs was 2525 ms.
Young people are less affected by PLDs than middle-aged and elderly people. The middle-aged people are most affected by PLDs. In addition, the spatial distributions of PLD effect were different among the three age groups. Optimizing the PLD for ASL imaging according to age and brain regions can obtain more accurate and reliable CBF values.
研究标记后延迟（PLD）对成人局部脑血流量（CBF）的影响并优化动脉自旋标记（ASL）磁共振（MR）成像的PLD具有重要意义。
2018年1月至2019年2月，对90名健康成年志愿者进行了采用三种PLD方案的伪连续ASL成像。健康受试者分为青年组（平均年龄30.63岁；年龄范围20 - 44岁）、中年组（平均年龄52.16岁；年龄范围45 - 59岁）和老年组（平均年龄66.07岁；年龄范围60 - 77岁）。预处理后，进行方差分析（ANOVA）和感兴趣区（VOI）分析，以比较各脑区的CBF。根据CBF随PLD变化的趋势及ANOVA结果，我们针对不同脑区和年龄组优化了ASL成像的PLD。
获得了每位受试者87个VOI（全脑灰质（全脑GM）和其他86个VOI）的CBF值。年轻人中具有统计学意义的VOI数量少于中年人和老年人（ANOVA分析中具有统计学意义（P<0.05）的VOI数量：青年组42个，中年组79个，老年组71个）。在青年组中，深部GM、枕叶和颞叶比边缘系统、额叶和顶叶受PLD的影响更大[具有统计学意义（P<0.05）的VOI/总VOI：8/8（深部GM）>8/12（枕叶）>（8/14）（颞叶）>5/12（边缘系统）>11/28（额叶）>（2/12）顶叶]。在中年组中，边缘系统、深部GM和颞叶比顶叶、额叶和枕叶受PLD的影响更大[具有统计学意义（P<0.05）的VOI/总VOI：12/12（边缘系统）=8/8（深部GM）>（13/14）（颞叶）>（11/12）顶叶>25/28（额叶）>9/12（枕叶）]。在老年组中，颞叶、顶叶和额叶比枕叶、边缘系统和深部GM受PLD的影响更大[具有统计学意义（P<0.05）的VOI/总VOI：14/14（颞叶）>12/12（顶叶）>22/28（额叶）>9/12（枕叶）>8/12（边缘系统）>5/8（深部GM）]。青年组中大多数VOI的最佳PLD为1525毫秒。然而，对于中年组和老年组，大多数VOI的最佳PLD为2525毫秒。
年轻人比中年人和老年人受PLD的影响更小。中年人受PLD的影响最大。此外，PLD效应的空间分布在三个年龄组中有所不同。根据年龄和脑区优化ASL成像的PLD可以获得更准确可靠的CBF值。
