Zhao Jing, Jing Bin, Chen Feng, Liu Jiaojiao, Wang Yuanyuan, Li Hongjun
Department of Radiology, Beijing Youan Hospital, Capital Medical University, No. 8, Xi Tou Tiao, You An Men Wai, Feng Tai District, Beijing 100069, China.
School of Biomedical Engineering, Capital Medical University, No. 10, Xi Tou Tiao, You An Men Wai, Feng Tai District, Beijing 100069, China.
Magn Reson Imaging. 2017 Apr;37:56-61. doi: 10.1016/j.mri.2016.10.019. Epub 2016 Oct 27.
Regional homogeneity (ReHo), a measurement from resting-state functional magnetic imaging (rs-fMRI) to reflect local synchronization of brain activities, has been widely explored in previous studies of neurological diseases. SIV infected model for detecting the neurological changes with progression was studied.
In the study, six rhesus macaques infected by simian immunodeficiency virus (SIV) were scanned by resting-state fMRI at the following time points: before SIV inoculation (baseline), 12weeks and 24weeks post inoculation (12wpi, 24wpi). Meanwhile, the immunological parameters including serum percentage of CD4+ T cell, CD4/CD8 ratio and absolute CD4+ T cell number were measured and analyzed.
In comparison of baseline, significant decreased ReHo was found in the left superior frontal gyrus, left superior temporal gyrus, left hippocampus, right precuneus, left angular gyrus, and bilateral occipital gyrus; in contrast increased ReHo in putamen at 12wpi. Moreover, at the time of 24wpi, decreased ReHo was observed in the right postcentral gyrus, left precentral gyrus, posterior cingulated gyrus and thalamus, while ReHo was increased in the left putamen, hippocampus, left anterior cingulated cortex and precentral cortex. The correlation analysis revealed that ReHo in the superior frontal gyrus showed negative association with CD4/CD8 ratio and positive with absolute CD4+ T cell number. The correlation analysis showed that percentage of CD4+ was correlated with the ReHo values in right middle frontal gyrus, bilateral thalamus and amygdala positively; negative relationship with left putamen, left superior frontal gyrus, left superior and middle temporal gyrus.
The study first indicates that hippocampus, putamen, frontal and occipital lobe were impaired by using rs-fMRI and correlated with immunological parameters. Thus, ReHo value can be utilized as a noninvasive biomarker of spontaneous brain activity changes caused by the progression of neurological impairments.
局部一致性（ReHo）是一种基于静息态功能磁共振成像（rs-fMRI）的测量方法，用于反映大脑活动的局部同步性，在先前的神经疾病研究中已得到广泛探索。本研究采用感染猴免疫缺陷病毒（SIV）的模型来检测疾病进展过程中的神经学变化。
在本研究中，对6只感染猴免疫缺陷病毒（SIV）的恒河猴在以下时间点进行静息态fMRI扫描：SIV接种前（基线）、接种后12周和24周（12周接种后、24周接种后）。同时，测量并分析包括血清CD4+T细胞百分比、CD4/CD8比值和绝对CD4+T细胞数量在内的免疫参数。
与基线相比，在左侧额上回、左侧颞上回、左侧海马、右侧楔前叶、左侧角回和双侧枕叶发现ReHo显著降低；相反，在12周接种后壳核的ReHo增加。此外，在24周接种后，右侧中央后回、左侧中央前回、后扣带回和丘脑的ReHo降低，而左侧壳核、海马、左侧前扣带回皮质和中央前皮质的ReHo增加。相关性分析显示，额上回的ReHo与CD4/CD8比值呈负相关，与绝对CD4+T细胞数量呈正相关。相关性分析表明，CD4+百分比与右侧额中回、双侧丘脑和杏仁核的ReHo值呈正相关；与左侧壳核、左侧额上回、左侧颞上回和颞中回呈负相关。
本研究首次表明，使用rs-fMRI可发现海马、壳核、额叶和枕叶受损，且与免疫参数相关。因此，ReHo值可作为神经功能障碍进展引起的自发性脑活动变化的无创生物标志物。
