Mn^2＋在活体眼增强磁共振视路示踪成像的量效和时效关系研究  

Study of Mn^2＋-enhanced magnetic resonance imaging for optic visual pathway in vivo

作　　者：王玮玲[1] 徐辉 胡运韬[1] 马雅玲[2] 吴建国[1] 李颖[1] 张君[2] 马志中[1] 

机构地区：[1]大学第三医院眼科北京大学眼科中心,北京100083 [2]宁夏医学院附属医院眼科,银川750004 [3]大学第三医院影像中心,北京100083

出　　处：《中华实验眼科杂志》2011年第7期585-590,共6页Chinese Journal Of Experimental Ophthalmology

基　　金：北医三院林护基金（64508-01）;08北医三院种子基金（Y2208-9-13）

摘　　要：背景近年来基于Mn^2＋作为神经示踪剂的功能磁共振成像（MRI）技术使得活体示踪视神经成为可能，但其应用的最佳浓度及示踪视神经的动态过程的研究报道较少。目的探讨不同浓度Mn^2＋在活体兔眼增强磁共振视神经示踪成像的量效和时效关系。方法48只青紫兰兔经左侧眼球上方距角巩膜缘1～1．5mm处玻璃体腔内分别注入不同浓度的MnCI2溶液（0．5、1、2、5、10、15、20、40mmol／L）25μl，右眼不进行任何注射作为对照。分别于注射后4、6、8、12、24、48、96、168h用1．5T超导MRI对兔头颅进行扫描，观察兔眼玻璃体腔注射后视神经、视交叉、对侧视束、外侧膝状体和上丘视觉传导通路的MRI显像情况，计算出上述部位的信噪比（SNR），分析Mn^2＋作为MRI视路示踪剂的最佳有效浓度和最佳显像时间。结果左眼玻璃体腔内注射0．5～1mmol／LMnCl2溶液后24h可见视神经显影较右眼视神经略增强，但双侧SNR值比较差异无统计学意义（t=1．17、t=0．95，P〉0．05）。左眼玻璃体腔内注射2mmol／L的MnCl，24h后，左侧视神经的SNR值明显高于右侧，差异有统计学意义（t=8．43，P〈0．05），但左侧外侧膝状体和上丘无明显强化显影，与右侧相比差异无统计学意义（t=0．04、t=0．22，P〉0．05）。左眼玻璃体腔注射10～40mmol／LMnCl，24hMRI视神经信号最强，此后随时间延长MRI信号逐渐减弱，168h后消失。视神经MRI图像的SNR值与玻璃体腔注入Mn“浓度呈正相关，（1，=66．234＋24．269lnx，F=374．15，P=0．000，R^2=0．984）。Mn^2＋在视觉通路的转输速度为（3．32＋0．19）mm／h。结论兔玻璃体腔注射25μl5—40mmol／L的MnCl，溶液24h，MRI能够清晰地显示整个视觉传导通路的信号增强，视路信号增强的程度呈MnCl，剂量依赖性并随着时间的延长呈现先增强后衰减的动态变化过程。Background Functional magnetic resonance imaging technique based on a manganese （Mn^2＋） tracer makes labeling the optic nerve in vivo possible. However studies on the optimal concentration and dynamic change after injection of Mn^2＋ are rare. Objective This study was designed to explore the time- and dosedependent response for Mn^2＋-enhanced MRI of visual pathway after intravitreal injection of MnCI2. Methods Different concentrations of MnC12 （ 0. 5,1 , 2,5,10,15,20,40 mmol/L） with a volume of 25 pd were intravitreally injected into the left eyes of 48 pigmented rabbits and were randomly divided into eight groups according to the drug concentrations. No reagent reg was injected into the right eyes as controls. MRI was performed at 4,6,8,12,24,48,96 and 168 hours after the administration of MnC12 to examine the imaging of the optic nerve,ehiasma,optic tract,lateral geniculate body and epithalamus. The signal-noise ratio of MRI in visual pathway was calculated and the optimal concentration and best imaging time after injection of MnC12 were assessed. The use of the animals followed the Regulations for the Administration of Affair Concerning Experimental Animals by State Science and TechnologyCommission. Results The imaging of the optical nerve in the left eyes was enhanced in comparison with the right eyes 24 hours after injection of 0.5-1 mmol/L MnC12 with a significant difference in SNR value between these two groups （ t = 1. 17, t = 0.95, P〉0.05 ）. 24 hours after the injection of 2 mmol/L MnC12 into the left eyes, the SNR va｜ue of the optic nerve on the left side was higher than the right side t = 8.43 ,P〈0.05 ） , but no image of lateral geniculate body and epithalamus was found in the left side compared to the right side （ t = 0.04, t = 0.22, P〉0.05 ）. The strongest imaging signal in optical nerve was seen in 24 hours after the intravitreal injection of 10-40 mmol/L MnC12 and decayed gradually from 24 to 168 hours with a transportation speed of （3.32＋0. 19） mm/h in rabbit v

关 键 词：锰离子 磁共振成像 视神经 视觉传导通路 玻璃体注射 

分 类 号：R77[医药卫生—眼科] R44[医药卫生—临床医学]