磁共振成像对干细胞移植后梗死心肌灌注的评价

Assessment of myocardial perfusion using MR with myocardial infarction after transplanting mesenchymal stem cells

目的:应用磁共振成像(MR)评价移植骨髓间质干细胞对梗死区心肌和血管再生的改变情况。方法:抽取香猪骨髓,体外分离骨髓间质干细胞,经5-氮胞苷(5-aza)转化。结扎香猪冠状动脉左前降支,经冠状动脉左前降支和梗死区注射骨髓间质干细胞;对照组注射培养液。3周和6周后,采用TurboFLASH序列行MR首过灌注及延迟成像扫描,绘制左心室各壁心肌信号强度-时间曲线,分析病变心肌信号-时间曲线特点。结果:对照组首过不强化,延迟扫描信号强度高于正常心肌,曲线上升时间、上升斜率、峰值时间和对比增强率明显低于正常心肌,峰值信号强度仅为正常心肌的(52.5±11.0)%。干细胞移植组首过及延迟均强化,延迟扫描时病变心肌信号强度高于正常心肌,信号强度-时间曲线仅曲线上升时间延长,峰值信号强度可达正常心肌(90.5±9.2)%。结论:MR扫描灌注及延迟成像扫描安全无创,结果准确可靠,能直接反映干细胞移植后心肌再生及血流再灌注的情况。

Objective： To evaluate transplanting mesenchymal stem cells （MSCs） effect on myocardial infarction using MR. Methods： Drew out bone marrow of pig and separated MSCs in vitro, conzerting with 5- aza. After ligating left anterior descending coronary artery （LAD）, infused MSCs in LAD and infarction area; the comparison group infused with culture fluid. Turbo FLASH were performed after 3 and 6 weeks to study first-pass myocardial perfusion. Signal intensity-time curve were drawn for analyzing. Results： Hypoenhancement on first-pass and hyperenhancement on delayed phase appeared in patiens who didn＇t receive thrombolysis therapy. There were significant differences between the time of upslope, the rate of upslope, peak time of the signal intensity-time curves and contrast enhancement ratio of ischemic myocardium and normal myocardium. The peak signal intensity of ischemic myocardium was （52.5 ± 11.0） % of normal. Hyperenhancement appeared on first-pass and delayed phase in revascularized patients receiving thrombolysis therapy. Only the time of upslope prolonged. And the peak signal intensity of ischemic myocardium was （90.5 ± 9.2 ） % of normal. Conclusion： Myocardial first-pass perfusion reflects the blood supply of the myocardium. To analyze the first-pass perfusion was helpful to assess blood supply of the damaged myocardium, and to evaluate the effect of thrombolysis therapy after transplanting MSCs.