| Summary: | 博士 === 義守大學 === 電機工程學系 === 107 === Atherothrombosis is a major cause of ischemic stroke and is a cause of ischemic heart disease due to myocardial infarction, which is one of the most common causes of death in the world as well. Nowadays, digital subtraction angiography (DSA) is still the gold standard in clinical arterial embolization examinations. However, it is invasive and risky. This study aimed to setup a middle cerebral artery occlusion (MCAO) SD rat model via microsurgery to induce stroke and longitudinally assess the progression of stroke using magnetic resonance imaging (MRI) techniques. Various MRI techniques including turbo spin echo (TSE), time of flight magnetic resonance angiography (TOF MRA) and diffusion weighted magnetic resonance imaging (DWI) were used to evaluate the intracranial tissue injury and recovery by image characteristics of cerebral tissues after MCAO. In the meantime, the correlation, sensitivity and specificity and the imaging feature of intracranial tissue injury between MCAO hemisphere and contralateral normal hemisphere were quantitatively analyzed and compared. It is expected to provide a reference in clinical diagnosis. Furthermore, the pathological analysis of infarcted or ischemic injury brain tissue was performed using triphenyltetrazolium chloride (TTC) stain to compare the MR imaging features and pathological characteristics. Regular MRI scans including TSE, TOF MRA and DWI were scheduled at 1, 2, 3, 7, 14, 21 and 28 days after MCAO microsurgery on Spray Dawley (SD) rats for longitudinal investigations. Twenty-one MCAO SD rats were classified into three groups according to the survival time, Group I died at 2-3 days (n=2), Group II at 8-9 days (n=9), Group III survived for more than 4 weeks (n=10). TOF MRA images showed an evidence of artery occlusion with signal void in intracranial arteries at MCAO side. Experimental results of all MR imaging techniques showed that cerebral edema dissipated within one week and there was no significant change thereafter. The time-varying signal intensity of all MRI techniques in hyper signal region of MCAO hemisphere has significant changed, but there were no significant change in contralateral normal hemisphere. It was found that the SD rats’ activity and MRI features were consistent with pathological analysis. In conclusion, the adopted MCAO SD rat model in this study was demonstrated to induce stroke effectively. The MCAO animal model had been successfully established on SD rats using arterial embolization microsurgery to assess intracranial tissue injury.
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