van der Toorn A, Dijkhuizen R M, Tulleken C A, Nicolay K
Department of in vivo NMR, Bijvoet Center for Biomolecular Research, Utrecht University, The Netherlands.
NMR Biomed. 1995 Sep;8(6):245-52. doi: 10.1002/nbm.1940080604.
The relaxation properties of water and metabolites were measured in rat brain following the occlusion of the middle cerebral artery (MCA) with localized 1H MRS. The PRESS sequence was employed to select volumes of 39 microL in the ischemic and the contralateral hemisphere. T1 and T2 relaxation times and peak intensities of water, choline containing compounds (Cho), creatine and phosphocreatine (Cre) and N-acetyl aspartate (NAA) in both hemispheres were determined at 3-6 h, 1 day and 3 or 4 days after occlusion. Lactate in the ischemic hemisphere was also quantified. The relaxation properties and peak intensities of NAA, Cre and Cho remained unchanged in the ischemic volume during the first 3-6 h of ischemia as compared to the contralateral volume. Water T2 was slightly increased in the ischemic volume. After 24 h the T1 and T2 of water and Cre and the T1 of Cho had increased significantly in the ischemic volume, while the peak intensities of Cho, Cre and NAA were reduced. It appears therefore that tissue changes which occur in the early phase of ischemia have no significant effects on the relaxation behaviour of the metabolites. However, ischemic brain damage affects the relaxation behaviour and concentration of the metabolites and water at later stages.
采用局部1H磁共振波谱法，在大鼠大脑中动脉（MCA）闭塞后测量水和代谢物的弛豫特性。使用点分辨表面线圈光谱（PRESS）序列在缺血半球和对侧半球选择39微升的体积。在闭塞后3 - 6小时、1天以及3或4天，测定两个半球中水、含胆碱化合物（Cho）、肌酸和磷酸肌酸（Cre）以及N - 乙酰天门冬氨酸（NAA）的T1和T2弛豫时间及峰强度。还对缺血半球中的乳酸进行了定量分析。与对侧体积相比，在缺血的最初3 - 6小时内，缺血体积中NAA、Cre和Cho的弛豫特性及峰强度保持不变。缺血体积中的水T2略有增加。24小时后，缺血体积中水和Cre的T1和T2以及Cho的T1显著增加，而Cho、Cre和NAA的峰强度降低。因此，缺血早期发生的组织变化对代谢物的弛豫行为没有显著影响。然而，缺血性脑损伤在后期会影响代谢物和水的弛豫行为及浓度。
