丙泊酚梯度镇静下功能核磁共振全脑功能的次序变化

Sequential brain functional changing on functional magnetic resonance imaging under propofol gradient sedation

目的不同剂量的丙泊酚在大脑中的作用部位是不同的,本研究拟动态地观察丙泊酚在脑内的作用途径,进一步探索其镇静机制。方法招募健康志愿者12例,男6例,女6例,年龄18~40岁,BMI 20~25 kg/m^2,ASA Ⅰ级。在未输注丙泊酚状态下进行一次静息态功能核磁共振(RS-fMRI)扫描,然后设定丙泊酚初始效应室浓度(Ce)为0.5 μg/ml,稳定5 min后完成一次RS-fMRI扫描。逐渐以0.5 μg/ml的增幅递增,每个Ce下均完成一次RS-fMRI扫描,直到Ramsay评分达到6分。在全脑范围内进行局部一致性(ReHo)的对比分析。结果与清醒时比较,Ce 0.5 μg/ml时小脑后叶、舌回、枕叶、颞叶等脑区ReHo值明显增加(P<0.05),前扣带回、中央前回、额叶等ReHo值明显降低(P<0.05)。与Ce 0.5 μg/ml时比较,Ce 1.0 μg/ml时额叶等脑区ReHo值明显增加(P<0.05),小脑后叶、海马旁回等ReHo值明显降低(P<0.05)。与Ce 1.0 μg/ml时比较,Ce 1.5 μg/ml时楔前叶、前扣带回、枕叶等脑区ReHo值明显增加(P<0.05),小脑前叶、梭状回、顶叶等ReHo值明显降低(P<0.05)。与Ce 1.5 μg/ml时比较,Ce 2.0 μg/ml时小脑前叶、小脑后叶、颞叶等脑区ReHo值明显增加(P<0.05),楔前叶、额叶、顶叶等ReHo值明显降低(P<0.05)。结论丙泊酚的作用部位广泛,包含皮层和皮层下中枢,表现为效应脑区分布和局部脑活动强度的动态变化。小脑、扣带回和楔前叶在丙泊酚镇静加深的过程中起关键作用。

Objective Different propofol dosages have different action-sites in the brain. This study intends to dynamically observe the role of propofol in the brain and further explore its sedation mechanism. Methods Twelve healthy volunteers were recruited in the study in the 18-40 age range, six males and six females, BMI 20-55 kg/m^2, ASA physical status Ⅰ. When no propofol infusion, a resting-state functional magnetic resonance imaging(RS-fMRI) was acquired. The initial Ce was set at 0.5 μg/ml and kept 5 min for equilibrium, then another RS-fMRI was acquired. After each scanning, a 0.5 μg/ml rising was achieved, and a RS-fMRI was acquired at each concentration until Ramsay sedation scale achieved 6. The comparative analysis of regional homogeneity(ReHo) of whole brain was performed. Results Compared with waking state, the ReHo values of posterior cerebellum lobe, lingual lobe, occipital lobe and temporal lobe were significantly increased(P < 0.05), and the ReHo values of anterior cingulate gyrus, precentral gyrus and frontal lobe were significantly decreased when Ce raised to 0.5 μg/ml(P < 0.05). Compared with Ce 0.5 μg/ml, the ReHo value of frontal lobe was significantly increased(P < 0.05), and the ReHo values of posterior cerebellum lobe and parahippocampal gyrus were significantly decreased when Ce raised to 1.0 μg/ml(P < 0.05). Compared with Ce 1.0 μg/ml, the ReHo values of precuneus gyrus, anterior cingulate gyrus and occipital lobe were significantly increased(P < 0.05), and the ReHo values of anterior cerebellum lobe, lobe, fusiform gyrus and parietal lobe were significantly decreased when Ce raised to 1.5 μg/ml(P < 0.05). Compared with Ce 1.5 μg/ml, the ReHo value of anterior/posterior cerebellum lobe and temporal lobe were significantly increased(P < 0.05), and the ReHo values of precuneus gyrus, frontal lobe and parietal lobe were significantly decreased when Ce raised to 2.0 μg/ml(P < 0.05). Conclusion The action sites of propofol are relatively broad, involving both cortex and subcortex, which are characterized by dynamic changes in the distribution of the activating brain regions and the intensity of local brain activity. The cerebellum, cingulate gyrus and precuneus play a key role in the process of propofol sedation deepening.