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目的 探讨18F-脱氧葡萄糖(FDG) PET/CT显像与心脏磁共振成像(CMR)对Beagle犬局部放射性心脏损伤(RIHD)的诊断价值.方法 将24只1岁龄健康雄性Beagle犬按照随机数字表法分为对照组及照射后3、6和12个月组,每组各6只;其中各照射组左心室前壁行单次20 Gy调强放疗.对全部犬行18F-FDG PET/CT心肌代谢显像和CMR检查,计算18F-FDG摄取增高区平均标准摄取值(SUVmax)及面积.全部检查结束后1周处死实验犬,取心脏进行Masson染色及电子显微镜检查.采用单因素方差分析比较组间差异.结果 对照组心肌18F-FDG几乎不摄取,照射后3个月即可见犬心肌18F-FDG摄取增加,照射后3、6和12个月组的心肌SUVmax分别为5.90±1.31、4.66±2.21和3.21±0.82,与对照组(1.13±0.21)的差异有统计学意义(F=11.81,P＜0.05);照射组18F-FDG摄取增高面积随着照射后时间延长逐渐下降(F=195.74,P＜0.01).CMR示照射后6和12个月组的心肌灌注降低、进行性纤维化加重;与对照组相比,照射后6和12个月组的舒张末期容积(EDV)和收缩末期容积(ESV)增加(F=15.479和16.908,均P＜0.01),而左心室射血分数(LVEF)下降(F=63.715,P＜0.01).Masson染色发现照射后心肌纤维化进行性加重;电子显微镜检查示照射后心肌线粒体变性肿胀,线粒体数量进行性减少.结论 照射后局部心肌18 F-FDG摄取增高对于RIHD的危险性有预测价值,18F-FDG PET/CT显像能早于CMR发现RIHD.“,”Objective To investigate the value of 18F-fluorodeoxyglucose (FDG) PET/CT imaging and cardiac MRI (CMR) in the diagnosis of radiation-induced heart disease (RIHD) in Beagle models.Methods Twenty-four normal male Beagle dogs (1-year old) were randomly divided into control group and irradiated groups (3-month,6-month and 12-month after radiation).The left anterior myocardium of Beagle dogs in irradiated groups was irradiated locally with a single dose of 20 Gy X-ray.Cardiac 18F-FDG PET/CT imaging and CMR were performed on all dogs,and the mean standardized uptake value (SUVmax) and the area of lesions with increased 18F-FDG uptake were obtained.After imaging examinations were finished,dogs were sacrificed and their hearts were taken out to perform Masson staining and electron microcopy.Oneway analysis of variance was used for data analysis.Results There was basically no uptake in myocardium in control group.The myocardium showed increased uptake of 18F-FDG in the irradiated groups.The SUV of myocardium in 3-month,6-month and 12-month after radiation groups and control group were 5.90± 1.31,4.66±2.21,3.21±0.82 and 1.13±0.21,respectively (F=11.81,P＜0.05).The area with increased 18F-FDG uptake in the irradiated groups decreased progressively with the prolongation of irradiation time (F =195.74,P＜0.01).The reduction in myocardial perfusion and myocardial fibrosis were observed by CMR early at 6-month after irradiation.Compared with the control group,the 6-month and 12-month after radiation groups had increased end diastolic volume (EDV) and end systolic volume (ESV;F =15.479 and 16.908,both P＜0.01),and decreased left ventricular ejection fraction (LVEF;F=63.715,P＜0.01).The progressive aggravation of myocardial fibrosis was displayed in irradiated groups by Masson staining.The mitochondria degeneration,swelling and the count reduction in irradiated groups were observed by electron microscopy.Conclusions The increased 18F-FDG uptake in the irradiated myocardium may predict the risk of RIHD.18F-FDG PET/CT imaging can detect RIHD earlier than CMR.