The Study Of Myocardial First-pass MR Perfusion Imaging Combined With DE-MRI In Different Period Of Infracted Swine Model

Objectives:The infarcted swine models, produced via intervention surgery, are taken myocardial first-pass MR perfusion imaging and DE-MRI after infarction 1 week and 8 week in order to know the changes of myocardial perfusion image, perfusion curve and pathology in different period and discuss the micro-vascular and pathophysiologic changes after myocardial infarction combined with DE-MRI. We can provide much more valuable information to evaluate the survival status of myocardial after infarction.Methods:1. Twelve swine model are taken under the guiding the intervention surgery. We place the balloon in LAD and induced infarction. The angiography was obtained to insured the infarction and position.2. The infracted swine models are taken myocardial first-pass MR perfusion imaging scan after infarction 1 week and 8 week. According to the feature of perfusion image and curve, we divide the 16 segments of left ventricular in the scanning field into 3 statuses, perfusion normal, perfusion reduced and perfusion absence, and record the result in order to know the number and distribution. We also record the peak signal and time to peak from the perfusion curve of perfusion normal, perfusion reduced and perfusion absence area.3. The infracted swine models are taken DE-MRI scan after infarction 1 week and 8 week. According to the feature of DE-MEI, we divide the 16 segments of left ventricular in the scanning field into 2 statuses, MI occurred and MI not occurred, and record the result in order to know the number and distribution.4. After the MR scan finished of 8 week infracted swine model, we kill the infracted swine model and take left ventricular myocardial to produce TTC samples. According to the feature of TTC samples, we divide the 16 segments of left ventricular in the scanning field into 2 statuses, MI-occurred and MI-not-occurred, and record the result in order to know the number and distribution.Results:1. In 12 swine,10 swine were successfully made infarcted model, the succeed rate was approximately 83.33%.2. In the 10 models after infarction 1 week, there were 78 perfusion abnormal segments had found, in which there were 57 perfusion reduced segments and 21 perfusion absence segments in myocardial first-pass MR perfusion imaging. While there were 33 MI-occurred segments had found in DE-MRI. The perfusion abnormal segments> The MI-occurred segments in DE-MRI. Peak signal comparison: perfusion normal area>perfusion reduced area>perfusion absence area. Time to peak comparison:perfusion normal area<perfusion reduced area<perfusion absence area.3. In the 10 models after infarction 8 week, there were 51 perfusion abnormal segments had found, in which there were 30 perfusion reduced segments and 21 perfusion absence segments in myocardial first-pass MR perfusion imaging. While there were 33 MI-occurred segments had found in DE-MRI. The perfusion abnormal segments> The MI-occurred segments in DE-MRI. Peak signal comparison: perfusion normal area> perfusion reduced area> perfusion absence area. Time to peak comparison:perfusion normal area<perfusion reduced area< perfusion absence area.4. There were 33 MI-occurred segments had found in TTC samples. The perfusion abnormal segments> The MI-occurred segments in TTC samples. The MI-occurred segments in DE-MRI=The MI-occurred segments in TTC samples.5. In myocardial first-pass MR perfusion imaging comparison between after infarction 1 week and 8 week, the perfusion abnormal segments in 1 week scan were more than 8 week scan. The perfusion reduced segments comparison:1 week scan>8 week scan. The perfusion absence segments comparison:1 week scan=8 week scan. In the same perfusion area comparison between 1 week and 8 week, the peak signal in 1 week scan was less than 8 week scan and the time to peak in 1 week scan was equal to 8 week scan.Conclusions:1. The infracted swine model, produced via intervention surgery, can be used to do research with myocardial first-pass MR perfusion imaging and DE-MRI.2. After left anterior descending artery is blocked 1 week and 8 week, the perfusion abnormal area is more than myocardial infarction area. It means that there is ischemic myocardial existence in the surrounding area of myocardial infarction.3. After left anterior descending artery is blocked 1 week and 8 week, the perfusion reduced area in 1 week scan is more than 8 week scan while the perfusion absence area in 1 week scan is equal to 8 week scan. It means that the micro-circulation in the surrounding area of myocardial infarction can be restored as usual while myocardial infarction area can not.4. The myocardial first-pass MR perfusion imaging combined with DE-MRI can be used to evaluate the survival myocardial with ischemic after myocardial infarction.