介入栓塞法建立小猪心肌梗塞模型及MRI研究

发布时间：2018-01-14 12:08

本文关键词：介入栓塞法建立小猪心肌梗塞模型及MRI研究　出处：《重庆医科大学》2009年硕士论文　论文类型：学位论文

【摘要】： 目的:利用小型猪建立心肌梗塞(Myocardial Infarction,MI)模型,比较正常与MI小猪MRI平扫表现及MRI灌注情况,并与其病理组织学对照,探索MI的MRI表现及其病理基础,为临床应用MRI诊断MI、监测干细胞移植治疗冠心病研究提供参考。材料与方法:MI模型的建立:9头雄性贵州小型猪,经股动脉穿刺插管,将自制黑色丝线栓子推注到冠状动脉左前降支(LAD)或左回旋(LCX)远端。术前及术后第2天,分别抽血行心肌酶谱、肌钙蛋白及血常规检查。所有6头存活小猪,术前及术后1、3、5周均进行MRI平扫及灌注扫描。术中与术后第二天死亡小猪只做了术前常规及灌注扫描。术后23天死亡小猪除行术前常规及灌注扫描外,还做了术后1、3周常规及灌注扫描。术后6周处死动物行病理组织学检查。 MRI检查技术:扫描序列包括平扫T1WI、T2WI、Fiesta、Tags序列,以及Gd—DTPA增强MR首过灌注成像、MDE延迟时相扫描成像。灌注成像采用(Peffusion-Weighted Imaging,PWI)序列,TR:3.3ms,TE:1.4ms,FA:23°,采集40期图像。经耳缘静脉注入Gd—DTPA0.1mmol/kg,注射流率:3.0mml/s,注射药后即刻启动扫描。在常规扫描上比较术前和术后心脏形态、信号及收缩功能的变化。利用MRI灌注图像建立信号强度-时间曲线,测量最大灌注斜率,最大峰值及峰值时间等。结果:一、MI动物模型及病理组织学检查进行股动脉穿刺栓塞冠脉的9头小猪均形成MI,1头术中发生室颤死亡,1头术后1天死亡;1头于23天死亡。42天后处死其余动物,病理大体及切片观察均见梗塞形成。MI模型存活率为66.7%(6/9)。所有受术小猪术前、术后均行冠脉造影。术前:各猪冠脉主干及各级分支血管通畅,管腔形态、大小未见异常。术后:所有受术小猪栓塞部位以下冠脉均无显影。 MI模型实验室检查指标术后较术前均有不同程度增高。9头受术小猪术前心电图均未见异常。冠脉栓塞5～10分钟后,3头猪即在心电监护Ⅰ、aVL、V1～V5导联出现不同程度ST段抬高;其中1头随即转变成室颤,最后心跳停止。二、MRI表现及与病理组织学检查对照关系 MRI平扫:小猪术前心脏MRI扫描,心脏大小、形态、信号、功能未见异常。6头存活小猪术后(1、3、5周)均做了MRI平扫及灌注扫描。Fiesta电影扫描均可见不同程度心脏节段的搏动减弱,Taggs序列缺血局部心室壁的网格运动幅度减低,随着时间延长,逐渐明显,甚至运动消失或出现反向运动;与术前对比:左室射血分数减少,左室运动幅度减小,左室舒张期末、收缩期末肌壁厚度未见明显改变。心脏大小、形态未见明显改变。活体及离体心脏扫描梗塞灶部位、面积与病理完全一致。 MRI灌注成像:灌注用药马根维显(Gadolinium-DTPA,GD-DTPA)。受术小猪术前心肌灌注后迅速强化,各节段心肌强化均匀,首过灌注未见低灌注区,延迟灌注未见强化。6头存活小猪术后(1、3、5周)均做了灌注扫描。首过灌注均发现灌注缺损,延迟扫描均见强化;低灌注区面积、信号值随时间没有明显差异;首过灌注最大上升斜率,术后较术前降低。术后首过灌注最大上升斜率及延迟灌注发生延迟强化节段数随时间有所减少。结论:介入栓塞法能形成彻底的MI。常规MRI能发现心MI后的异常改变。MRI灌注成像能准确诊断、定位MI。MRI扫描能对MI长期跟踪随访。
[Abstract]:Objective: to establish a myocardial infarction using miniature swine (Myocardial Infarction MI) model, compared with MI normal pig MRI scan and MRI perfusion, and pathology, to explore the MRI features and pathological basis of MI, for the clinical application of MRI diagnosis of MI, monitoring of stem cell transplantation in the treatment of coronary heart disease research to provide the reference.
Materials and methods: the MI model: 9 male Guizhou miniature pigs with catheterization of femoral artery, the self-made black thread embolus injection to the left anterior descending coronary artery (LAD) or left circumflex (LCX) distal. Second days before and after operation, respectively. Blood for myocardial enzymes, troponin egg Rhizoma Bletillae blood routine examination. All 6 survived pigs were performed MRI scan and perfusion 1,3,5 weeks before and after the surgery. The intraoperative and postoperative day second death piggy only do preoperative routine and perfusion scan. Pigs except for routine preoperative perfusion scan and death 23 days after operation, but also to do the 1,3 weeks after surgery and routine perfusion scan. Animal pathology examinations were performed at 6 weeks after operation.
MRI examination: the scanning sequences included plain T1WI, T2WI, Fiesta, Tags and Gd sequences, DTPA enhanced MR first pass perfusion imaging, MDE delayed phase scanning imaging. Perfusion imaging using (Peffusion-Weighted Imaging, PWI) TR:3.3ms, TE:1.4ms, FA:23 sequence, 40 degrees, collecting images. Injection of Gd - DTPA0.1mmol/kg. By the ear vein injection rate: 3.0mml/s, immediately start scanning after injection.
The changes of cardiac morphology, signal and systolic function before and after operation were compared on routine scanning. The signal intensity time curve was established by MRI perfusion image, and the maximum perfusion slope, maximum peak value and peak time were measured.
Results: 1. MI animal model and histopathological examination
9 piglets of femoral artery puncture coronary artery embolism were formed MI, fatal ventricular fibrillation occurred in 1 head, 1 head died 1 days after the operation; 1 on the 23 day death.42 days after the rest of the animal, infarction survival rate of.MI model was 66.7% and showed pathological section observation (6/9) of all. Of pigs before operation, postoperative underwent coronary angiography. Preoperative: the porcine coronary artery trunk and branch patency, lumen size, no abnormality. After the operation: all cases had no coronary embolism following pig development.
MI model laboratory indexes after operation were increased.9 of pig head preoperative electrocardiogram showed no abnormal coronary embolism. 5~10 minutes later, 3 pigs in the ECG I, aVL, V1 ~ V5 leads with varying degrees of ST elevation; 1 of them immediately head into ventricular fibrillation, finally to stop the heart.
Two, MRI expression and comparison with histopathological examination
MRI scan: Pig preoperative cardiac MRI scan, heart size, shape, signal, no abnormal function of.6 survived after pigs (1,3,5 weeks) were done MRI plain and perfusion.Fiesta scan were showed different degrees of heart beating segment decreased, grid motion amplitude Taggs sequence local ventricular wall ischemia the decreased with the prolongation of time, gradually, even sports disappear or reverse movement; compared with the preoperative left ventricular ejection fraction decreased left ventricular motion decreases, left ventricular end diastolic and end systolic muscle wall thickness had no obvious change. The size of heart, there was no obvious morphological change in vivo and in vitro cardiac scan. The infarct area and the pathological part, exactly the same.
MRI perfusion imaging: infusion Magnevist (Gadolinium-DTPA, GD-DTPA). Preoperative myocardial perfusion of pig quickly after strengthening, segments even strengthened, first pass perfusion was low perfusion, delayed perfusion was not enhanced.6 survival after resection of head pig (1,3,5 weeks) were done first pass perfusion perfusion scan. Showed perfusion defects were seen in delayed enhancement scan; area of low perfusion area, the signal value over time have no obvious difference; first pass perfusion maximum rise slope, postoperative perfusion decreased. The maximum rise slope of the first pass and delayed perfusion occurred delayed enhancement segments decreased with time.
Conclusion: interventional embolization can form a thorough MI. routine MRI, which can detect abnormal changes after cardiac MI..MRI perfusion imaging can accurately diagnose, and MI.MRI scanning can be a long-term follow-up for MI.

【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：R445.2;R542.22;R-332

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