摘要
目的 用氢质子磁共振波谱 (1 HMRS)结合扩散加权成像连续观察大白鼠大脑中动脉线栓 (MCAO)模型2 4h内代谢物的变化规律 ,探讨1 HMRS对脑缺血性损伤和缺血再灌注后脑恢复程度的敏感性。材料与方法 共 2 9只Wistar成年鼠 ,4 .7T超导磁共振仪扫描。术前先取其中 8只作为正常组扫描 ;再将这 2 9只随机分为对照组 (只结扎左侧颈总动脉和颈外动脉 ) 7只 ,永久性大脑中动脉栓塞组 7只 ,缺血 30min再灌组 5只 ,缺血 1h再灌组 5只 ,缺血 2h再灌组 5只。检查完成后取栓塞组和再灌组的鼠脑四氮唑 (TTC)染色。结果 (1 )在正常组 ,双侧代谢物分布对称 ,胆碱类复合物 (Cho) /肌酸和磷酸肌酸 (CrandPCr)、N 乙酰天门冬氨酸 (NAA) /Cr没有明显的差异 (P >0 .0 5 ) ;在对照组 ,双侧Cho/Cr、NAA/Cr也无显著性差异 (P >0 .0 5 ) ,没有检测到乳酸 (Lac)。 (2 )本实验最早观察到MCAO后 2 2min兴趣区内出现Lac ,DWI为高信号 ,ADC值下降。缺血 2 4h内Lac持续升高 ,以 0 .5hLac水平为基数 ,6h内升高最快 ,增加了 1 .2倍 ;1 2h内增加到 1 .6 2倍 ;2 4h后为 1 .4 7倍 ,稍显降低。相反 ,NAA呈持续下降 ,0 .5～ 1h内变化不明显 ,1 .5± 0 .2h观测到NAA下降 ;2h内下降 (2 3.6± 1 3.1 ) % ;1 2h内下降 (6 8.2± 2 1 .9) % ;2
Objective To successively observe the metabolic changes in the white rat model of cerebral middle artery occlusion (MCAO) within 24 hours after ischemia with 1 hydrogen magnetic resonance spectroscopy ( 1 HMRS) and diffusion weighted imaging (DWI), and to assess the sensitivity of 1 HMRS in evaluating brain ischemic injure and recovery degree after reperfusion.Materials and Methods A total of 29 adult Wistar rats were scanned with 4.7 T MRI unit. Before the procedure, 8 from the 29 rats, used as normal group, were randomly selected and scanned. Then, the 29 rats were randomly divided into (1) control group (n=7, only left common carotid and external carotid arteries were occluded), (2) permanent MCAO group (n=7), (3) 30min reperfusion group (n=5), (4) 1h reperfusion group (n=5), and (5) 2h reperfusion group (n=5). After the examination, triphenyltetrazolium chloride (TTC) stain was made in the rats of the embolized and reperfusion groups.Results (1) In the normal group, bilateral metabolites were symmetrically distributed, and Cho/Cr, NAA/Cr showed no significant difference (P>0.05), while in the control group, no significant difference in Cho/Cr and NAA/Cr was found between two sides (P> 0.05), and Lac was not detected. (2) The earliest detection of Lac in ROI was at 22min after MCAO, which showed high intensity on DWI with a decrease of ADC. During the first 24 hours after ischemia, Lac kept going up. Take 0.5h Lac level as the base line, it rapidly increased to 1.2 times during the first 6h, to 1.62 times in 12h, and to 1.47 times in 24h. In contrast, NAA was continuously decreasing during the first 24h. Within 0.5～1h no obvious change of NAA was seen. A decrease of NAA was detected in 1.5±0.2h. NAA showed a reduction of (23.6±13.1)% in 2h, (68.2±21.9)% in 12h, and (95.5±4.3)% in 24h. Cho and Cr were relatively stable in 2h. (3) The average time of Lac decrease or disappearance was 45min in 30min reperfusion rats, and 68min in 1h reperfusion rats. On DWI, the hyperintense lesions were decreased in size. In 2h reperfusion rats, Lac kept elevated, while on DWI the lesions enlarged.Conclusion 1 HMRS is very sensitive in detecting the dynamic changes of cerebral ischemia and reperfusion in vivo, it can quantitatively reflect biochemical alteration of cerebral ischemic tissue and the occurrence and development of cerebral ischemia.
出处
《临床放射学杂志》
CSCD
北大核心
2002年第6期464-469,共6页
Journal of Clinical Radiology
基金
为"波谱与原子分子国家重点实验室"基金资助项目 (No:T15 2 0 13)
关键词
脑缺血
大脑中动脉线栓阻塞
氢质子磁共振波谱
实验研究
Cerebral ischemia Cerebral middle artery occlusion Hydrogen magnetic resonance spectroscopy
