目的 应用1氢磁共振波谱(1H MRS)脑温测量技术评价猴大脑中动脉闭塞再灌注模型不同缺血区的脑温变化.方法 制备MR兼容恒温控制系统,利用脑生理液体模修正温度-化学位移方程,检测正常猴脑脑温.制作猴大脑中动脉闭塞再灌注模型,行动脉闭塞期及再灌注后1、3、6、12、24 h MR DWI、PWI、T2 WI及1H MRS检查,计算不同缺血区的脑温.结果 修正后的温度-NAA化学位移方程为T=37+ 100(CSNAA-2.039).正常猴脑平均脑温37.16℃.动脉闭塞期,不同缺血区脑温均高于对侧半球(P<0.05),缺血半暗带(IP)脑温升高最明显.再灌注后核心坏死区脑温先迅速下降而后升高,IP和低灌注区脑温缓慢下降,逐渐恢复正常.结论 1H MRS可无创性测量脑温,可评估脑组织的缺血程度.
Objective To explore the application of temperature measurement technique by 1H magnetic resonance spectroscopy (MRS) in an ischemia monkey model.Methods A MRI-compatible thermostatic control system was developed.And the equation was corrected between brain temperature and the chemical shift of N-acetyl-L-aspartic acid (NAA) through in vitro experiment.The normal brain temperature of monkey brain was measured.And a monkey model of middle cerebral artery occlusion (MCAO) and reperfusion was established.MR diffusion weighted imaging (DWI),perfusion weighted imaging (PWI),T2 weighted imaging and 1H MRS were performed at artery occlusion stage,1h,3h,6h,12h and 24h post-recanalization.The brain temperatures of different ischemic regions were calculated by the modified brain temperature-chemical shift equation.Results The modified equation was as follows:T =37 + 100(CSNAA-2.039).The normal brain temperature was 37.16 ℃.The models were successfully established in 4 monkeys.During arterial occlusion stage,the brain temperature of different ischemic tissue was higher than the contralateral hemisphere (P < 0.05),including infarct core,ischemic penumbra (IP) and oligemic region.And the highest temperature was in IP.After recanalization,the brain temperature of infarct core decreased rapidly during an early stage and was accompanied by a subsequent increase.However,the brain temperature of IP and oligemic region decreased slowly to normal.Conclusion 1H MRS may be used to measure brain temperature noninvasively so as to gauge ischemic degree.