Abnormality of water molecular diffusion of rats after focal cerebral ischemia / 中国组织工程研究

ABSTRACT

BACKGROUND: Some researches report that diffusion-weighted imaging (DWI) can appear abnormal signal in minutes after cerebral ischemia.OBJECTIVE: To investigate the manifestation and regularity of diffusion coefficient in middle cerebral artery occlusion (MCAO) of rats after cerebral ischemia.DESIGN: Randomized controlled study.SETTING: Neurological Department of Clinical College of ChongqingMedical University.MATERIALS: The experiment was conducted at the Radiological Department of the First Affiliated Hospital of Chongqing Medical University from April to July 2004. Totally 18 adult Wistar rats with clean grade were randomly divided into three groups: control group, sham operation group and cerebral ischemia group with 6 rats in each group.METHODS: The origin of right middle cerebral artery was blocked with filament into right internal carotid. In the sham-operated group, the filament was just inserted into the common carotid artery not into the origin of middle cerebral artery, rats in normal control group were not treated with anything after anesthesia. MRI experiments were performed on a 1.5 T GE signa Highspeed NMR spectrometer to obtain DWI and ADC values at the time-point of 7, 15, 30, 60 minutes, 3,6, 12, 24 hours, 3, 7, 15 days, 1 and 2 months after operation.MAIN OUTCOME MEASURES: Changes of ADCs in infarct hemisphere and contralateral hemisphere.RESULTS: There was no significant change in MRI T1-and T2-weighted imaging in rats at 7 minutes post-infarction, but abnormal high intensity was emerged during the period of 1 hour to 3 hours, and enlarged over time. Finally, the infarction area located the right basal ganglia and the frontal-parietal lobes at 12 hours and increased less significantly later.Focal abnormal high signal was noted in DWI 7 minutes after cerebral ischemic insult, and the ADC values was decreased at the same time,reduced gradually after significant recover at 30 minutes, dropped to the lowest level at 12 hours and again increased at 24 hours, since then all the ADC values were remained high throughout follow-up, which increased by 5 times at 2 months than that at 12 hours. Correspondingly,rADC values showed the contrary pattern of evolution.CONCLUSION: It is reflected that ADC is highly sensitive not only to onset of cerebral ischemia but also to chronic cerebral ischemia.