摘要目的 评价双源CT(DSCT)心肌灌注碘成像诊断犬实验性急性心肌梗死的可行性和准确性.方法 6只犬开胸结扎冠状动脉左前降支(LAD)建立心肌梗死模型,另3只仅开胸而不结扎LAD作为对照组,分别于术前及术后3 h行DSCT心肌灌注碘成像扫描,然后行99Tcm-甲氧基异丁异腈(MIBI)SPECT静息态心肌灌注检查.检查结束后立即取出心脏,进行氯化三苯基四氮唑(TTC)染色,分析心肌梗死范围,观察病理学改变.将左心室壁分为17个节段,确定DSCT心肌灌注碘成像和SPECT上心肌梗死的节段数.利用t检验分析梗死区和非梗死心肌CT值的差异,以病理结果为金标准分别评价DSCT心肌灌注碘成像和SPECT心肌灌注对显示心肌梗死的敏感性、特异性,Kappa检验分析结果的一致性.结果 正常组及缺血组术前CT均未见明显心肌梗死区,缺血组术后DSCT心肌灌注碘成像与SPECT见心尖前壁、心尖间隔灌注稀疏甚至缺损;DSCT扫描见结扎冠状动脉供血区明显低密度区,增强后CT值[(34.75±16.66)HU]较术前[(123.18±15.38)HU]明显降低(t=10.526,P＜0.01).与金标准对照,DSCT心肌灌注碘成像诊断心肌梗死的敏感性、特异性、阴性预测值和阳性预测值分别为85.0%(34/40)、84.1%(95/113)、65.4%(34/52)、94.0%(95/101);Kappa值为0.63;而 SPECT诊断心肌梗死的敏感性、特异性、阴性预测值和阳性预测值分别为82.5%(33/40)、90.3%(102/113)、75.0%(33/44)、93.6%(102/109),Kappa值为0.71.结论 DSCT心肌灌注碘成像可用于检测犬急性心肌梗死,诊断准确性与静息SPECT心肌灌注成像相当.

abstractsObjective To investigate the feasibility and accuracy of dual energy CT myocardial iodine maps in detecting acute myocardial infarction in canine model. Methods Myocardial ischemia model was made by ligaturing left anterior descending coronary arteries (LAD) after thoracotomy in six dogs, while another 3 dogs undergoing thoracotomy not ligaturing LAD as control group. Before and three hours after operation, dual-source CT (DSCT) was performed, followed by resting 99Tcm-MIBI single photon emission computed tomography myocardial perfusion imaging. Then, dogs were sacrificed, and the hearts were removed, triphenyltetrazolium chloride staining and conventional HE staining were performed. CT number of non-ischemic and ischemic regions were measured and analyzed. The wall of the left ventricle in the short axis was divided into 17 segments, the segments of myocardial perfusion defect in DSCT myocardial iodine maps, SPECT, and pathology were determined. Student t test was used to analyze the difference of CT number between infarcted and non-infarcted myocardium. Kappa test was used for the accuracy of DSCT myocardial iodine maps and SPECT in detecting myocardial ischemia according to the pathological results. Results No abnormal regions were detected using DSCT myocardial iodine maps in preoperative control and infarction group. After thoracotomy, partial sparse or defective perfusion was consistently noted in six dogs' apical anterior and partition wall in both DSCT myocardial iodine maps and SPECT. In the infarcted group, the attenuation of infarction region (34.75 ± 16.66) HU was significantly decreased compared with preoperative measurements ( 123. 18 ± 15.38 ) HU ( t = 10. 526, P ＜ 0. 01 ); decreased perfusion in the infarcted region was also noted in the DSCT myocardial iodine maps and SPECT. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of DSCT myocardial iodine maps and SPECT were 85.0% (34/40) , 84. 1% (95/113) ,65.4% (34/52) ,94. 0%(95/101) ,and 82. 5% (33/40), 90. 3% ( 102/113 ) ,75.0% (33/44) ,93.6% ( 102/109 ), respectively.Kappa values were 0. 63 and 0. 71 for the agreement of DSCT myocardial iodine maps and SPECT.Conclusion DSCT myocardial iodine maps is comparable diagnostic accuracy with rest SPECT myocardial perfusion imaging in detection of acute myocardial infarction in a canine model.