^(18)F-FDG PET显像评价急性心肌梗死后梗死区炎性反应演变及其与左心室重构的关系

Dynamic evaluation of inflammation in infarct area after acute myocardial infarction and its relationship with left ventricular remodeling by^(18)F-FDG PET imaging

目的应用^(18)F-FDG PET显像评价急性心肌梗死(AMI)后早期梗死区炎性反应及其动态演变,并分析其与左心室(简称左室)重构进展(LVRP)的关系。方法选取16头巴马小型猪(4~6月龄,雌雄各半),使用球囊封堵冠状动脉左前降支建立AMI模型。分别于建模前、AMI后1、5、8、14 d行^(18)F-FDG PET显像评价AMI后局部炎性反应,获取梗死区^(18)F-FDG SUV比值(SUVR)及摄取范围占左室的百分比(F-extent)、脾脏及骨髓SUVR;在上述时间点及AMI后28 d分别行超声心动图及99Tc m-甲氧基异丁基异腈(MIBI)SPECT心肌灌注显像评价左室容积(LVEDV和LVESV)、左室射血分数(LVEF)和心肌灌注缺损范围,分析AMI前后各时间点上述指标的动态演变。AMI后28 d LVRP程度用ΔLVESV表示[ΔLVESV(%)=(LVESV_(AMI 28 d)-LVESV_(AMI 1 d))/LVESV_(AMI 1 d)×100%]。采用重复测量方差分析、Kruskal-Wallis秩和检验、Pearson相关分析处理数据。结果12头猪成功建模并完成研究。AMI后梗死区炎性反应可持续至14 d,建模前、AMI后1、5、8及14 d梗死区SUVR分别为1.03±0.08、3.49±1.06、2.93±0.90、2.38±0.76、1.63±0.62(F=49.31,P<0.001)。建模前,AMI后1、5、8及14 d梗死区F-extent分别为0、(40.08±12.46)%、(40.00±12.76)%、(31.08±12.82)%、16.50%(7.25%,22.00%)(H=37.61,P<0.001)。但AMI前后各时间点骨髓及脾脏SUVR无明显差异(F值:0.69、0.77,均P>0.05)。AMI后1 d梗死区SUVR、F-extent均与LVRP相关(r值:0.82、0.70,P值:0.001、0.035)。结论^(18)F-FDG PET显像可评价AMI后梗死区炎性反应及其动态演变。AMI后1 d时梗死区炎性反应程度重,随后逐渐减低。AMI后1 d时^(18)F-FDG PET显像反映的梗死区炎性反应程度及范围与AMI后LVRP密切相关。

Objective To evaluate inflammation early in the infarct zone and its dynamic changes after acute myocardial infarction(AMI)using^(18)F-FDG PET imaging,and analyze its relationship with left ventricular remodeling progression(LVRP).Methods Sixteen Bama miniature pigs(4-6 months old,8 females)were selected.AMI models were established by balloon occlusion of the left anterior descending artery.^(18)F-FDG PET imaging was performed before AMI and at days 1,5,8,and 14 post-AMI to evaluate the regional inflammation response.^(18)F-FDG SUV ratio(SUVR)and the percentage of uptake area of left ventricle(F-extent)in the infarct zone,and the SUVRs of the spleen and bone marrow,were measured.Echocardiography and 99Tc m-methoxyisobutylisonitrile(MIBI)SPECT myocardial perfusion imaging(MPI)were performed at the above time points and on day 28 post-AMI to assess left ventricular end-diastolic volume(LVEDV),left ventricular end-systolic volume(LVESV),left ventricular ejection fraction(LVEF),and myocardial perfusion defect extent.The degree of LVRP at day 28 post-AMI was defined asΔLVESV(%)=(LVESV_(AMI 28 d)-LVESV_(AMI 1 d))/LVESV_(AMI 1 d)×100%.Data were analyzed using repeated measures analysis of variance,Kruskal-Wallis rank sum test and Pearson correlation analysis.Results Twelve pigs were successfully modeled and completed the study.Inflammation in the infarct zone persisted until day 14 post-AMI.The SUVR of the infarct zone pre-AMI and at days 1,5,8,and 14 post-AMI were 1.03±0.08,3.49±1.06,2.93±0.90,2.38±0.76,and 1.63±0.62,respectively(F=49.31,P<0.001).The F-extent values in the infarct zone pre-AMI and at days 1,5,8,and 14 post-AMI were 0,(40.08±12.46)%,(40.00±12.76)%,(31.08±12.82)%,and 16.50%(7.25%,22.00%),respectively(H=37.61,P=0.001).There were no significant differences in the SUVRs of bone marrow and spleen before and after AMI(F values:0.69 and 0.77,both P>0.05).At day 1 post-AMI,both SUVR and F-extent in the infarct zone were significantly correlated with LVRP(r values:0.82 and 0.70,P values:0.001 and 0.035).Conclusions^(18)F-FDG PET imaging can be used to evaluate inflammation in the infarct area and its dynamic changes after AMI.Inflammation in the infarct area is severe at day 1,and then gradually decreases.The extent and severity of inflammation visible on^(18)F-FDG PET imaging 1 d after AMI are closely related to LVRP.