大鼠视觉皮层动态锰离子增强磁共振功能成像研究

Dynamic manganese-enhanced functional magnetic resonance imaging on rat visual cortex

目的应用动态锰离子增强磁共振技术行大鼠视觉皮层功能成像，为神经系统功能的研究提供方法。方法成年雄性Wistar大鼠6只，右颈外动脉插管后于连续的4个时段分别进行不同处理，第一时段（5min）不给予药物，无视觉刺激；第二时段（10min）经右颈外动脉注射甘露醇和氯化锰，无视觉刺激；第三时段（15min）仅注射氯化锰，给予视觉刺激；第四时段（5min）注射氯化锰与谷氨酸混合液，无视觉刺激。每一时段处理后立即进行大鼠头颅磁共振成像，应用SPM软件进行图像的配准和平滑处理，应用Matlab软件得出图像的配色图及等高线图：选取视觉皮层进行兴趣区（ROI）分析，观察不同处理后磁共振图像中脑内特异性增强区域并比较大鼠视觉皮层的信号强度。结果磁共振图像分析显示第一、二时段处理后大鼠脑内未发现特异性增强区域。第三时段处理后大鼠右侧视觉皮层特异性增强，第四时段处理后大鼠右侧脑内多个核团特异性增强：ROI分析显示第三时段处理后的视觉皮层信号强度（1．897±0．172）明显强于第二时段（1．549±0．163），差异有统计学意义（P〈0．05）。结论动态锰离子增强磁共振成像技术能分析大鼠视觉皮层功能活动，可做为研究神经系统功能的新方法。

Objective To map the vision cortex of rats by dynamic manganese-enhanced functional magnetic resonance imaging and provide a method for researching the nervous function. Methods Six adult male Wistar rats were chosen and the process was divided into 4 continuous phases. No agent was injected into the rats in the first phase （5 min）. Disrupting the BBB with mannitol and injecting manganese chloride were performed in the right internal carotid artery （ICA） in the second phase （10 min）. In the third phase （15 min）, manganese chloride was administrated into the. right ICA and vision stimulation was performed before the imaging process. The mixed liquor of manganese chloride and glutamate was injected into the rats in the forth phase （5 min）. MRI was performed instantly after the handles in each phase. SPM and Matlab software were employed to help analyze the imaging data. Region-of-interest （ROI） was recorded to observe the stimulated regions and compare the signal intensity in the visual cortex. Results No specific enhanced region was found in the rat brain in the first and second phases. The right visual cortex was enhanced specifically on T1W1 in the third phase. Many brain regions of the right hemisphere, the sites that agents was injected, were obviously enhanced in the forthphase. ROI analysis showed that the signal intensity in the third phrase （1.897±0.172） was significantly stronger as compared with that in the second phrase（1.549±0.163）（P〈0.05）. Conclusion The dynamic manganese-enhanced functional magnetic resonance imaging can analyze the functional activities of the vision cortex in rats and provide a new method for researching the fimction of the nervous system.