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目的通过冠状动脉注射坏死组织亲和性非卟啉类顺磁性对比剂(ECⅢ-60)后 MR 延时影像与病理对照的方法明确其强化区与梗死心肌的关系,并与静脉注射非特异性对比剂钆喷替酸葡甲胺(Gd-DTPA)比较,以期为 MRI 准确评价心肌活性提供可靠的病理依据。方法经导管采用闭胸法成功建立8只猪的急性心肌梗死再灌注模型。经静脉以0.2 mmol/kg 快速团注 Gd-DTPA 后行心电激发的心脏 MR 短轴面T_1WI,延时扫描至局部 Gd-DTPA 完全消失。然后再以0.0025 mmol/kg 经冠状动脉导管缓慢注入 ECⅢ-60后短轴面 T_1WI,延时成像至5 h。比较分析 ECⅢ-60增强 MRI 延时强化区和金标准病理所示梗死区的关系;并和 Gd-DTPA 增强 MRI 的对比增强效果(CR)与范围(RIS)进行比较。结果 ECⅢ-60增强 MRI 可见梗死区的信号较正常对照区明显升高(CR>3.0)并持续超过5 h,其强化区相对面积[占同层面左室面积的百分率为(11.84±3.63)%]与 TTC 染色心肌梗死面积[(11.78±3.64)%]一致(t=2.251,P>0.05),两者呈正相关,其决定系数为 r=0.999。Gd-DTPA 也能产生 CR>3.0的强化效果,但对梗死区的对比度在2 h 内逐步消失。结论坏死亲和性对比剂增强 MRI 能持续准确地反映心肌梗死,能成为冠状动脉介入术后心肌活力评估的有潜在价值的方法。
OBJECTIVE: To determine the relationship between enhanced myocardial infarction (MI) and myocardial infarction (AMI) by means of coronary angiography (MR) angiography and pathological contrast of necrotic tissue non-porphyrin paramagnetic contrast agent (ECⅢ-60) Gd-Gd-DTPA, in order to provide a reliable pathological basis for the accurate evaluation of myocardial activity by MRI. Methods Acute myocardial infarction reperfusion model of 8 pigs was successfully established by catheterization and closed chest method. After intravenous injection of 0.2 mmol / kg Gd-DTPA fast cardiac electrocardiographic heart MR T 1 WI, delayed scan to local Gd-DTPA completely disappeared. After that, the short axis T_1WI of ECⅢ-60 was infused slowly via coronary catheter at a dose of 0.0025 mmol / kg, and imaging was delayed to 5 h. The relationship between EC Ⅲ-60 enhancement MRI delayed infarction area and gold standard pathology was compared and analyzed. The contrast enhancement (CR) and range (RIS) of Gd-DTPA enhanced MRI were compared. Results The signal intensity of infarction in EC Ⅲ-60 enhanced MRI was significantly higher than that in normal control (CR> 3.0) and continued for more than 5 h. The relative area of intensified area [(11.84 ± 3.63)%) ] Was the same as the area of TTC-stained myocardial infarction [(11.78 ± 3.64)%] (t = 2.251, P> 0.05). The coefficient of determination was r = 0.999. Gd-DTPA also produced an enhancement of CR> 3.0, but the contrast to the infarct zone gradually disappeared within 2 h. Conclusion Necrosis Affinity Contrast Enhanced MRI can consistently and accurately reflect myocardial infarction and can be a potentially valuable method for assessing myocardial viability after coronary intervention.