Experimental study in detection of myocardial ischemia with stress dual-phase 18F-FDG myocardial PET/CT / 中华核医学与分子影像杂志

ABSTRACT

Objective To explore the value of stress dual-phase (early and delayed phases)18 FFDG myocardial PET/CT in detection of myocardial ischemia.Methods Ten swine were prepared as ischemic models and underwent 3 imaging procedurespre-model stress (8 swine),post-model rest (8 swine)and post-model stress dual-phase imaging (10 swine).To perform stress dual-phase imaging,the tested subjects were fasted for more than 12 h and underwent early-phase PET imaging at 50 min after the intravenous injection of 18F-FDG (5 MBq/kg) for 10 mins,and followed by a dobutamine stress test,and then delayed-phase PET imaging at 50 min after the stress test for another 10 mins.The post-model rest dual-phase imaging was performed in almost the same way except that there was no dobutamine-loading.18F-FDG uptake image was qualitatively analyzed and classified into 4 levels1 =no uptake,2 =diffuse uptake,3 =focal uptake,4=focal on diffuse uptake.Level 1 or 2 was considered as normal.If the focal uptake (level 3 or 4)was found on anterior wall or septum,ischemia was diagnosed.x2 test was used to determine the difference of the rate of ischemic myocardium between the two phases.18F-FDG uptake ratio of the anterior wall to posterior wall (K) of the left ventricle was calculated (K1 for early phase and K2 for delayed phase).Wilcoxon rank sum test was applied to determine the difference between K1 and K2.Results CAG showed LAD stenosis ＞70％ in all swine.In pre-model stress dual-phase imaging,no ischemia was detected at two phases (8/8 for level 1 or 2,0 for level 3 or 4).There was no significant difference between K1 and K2(1.08±0.10,1.11 ±0.10; Z =-1.48,P＞0.05).In post-model rest dual-phase imaging,the rate of ischemic myocardium was not significantly different between early and delayed phases (1/8,3/8 ; x2 =0.50,P＞0.05).There was no significant difference between K1 and K2(1.47±0.28,1.28±0.40; Z=-2.02,P＞0.05).In post-model stress dual-phase imaging,the rate of ischemic myocardium between the two phases was statistically different (4/10,10/10;x2=4.17,P＜0.05),and the difference between K1 and K2 was also significant (1.55±0.32,1.86±0.39; Z=-2.49,P＜0.05).Conclusion Stress dual-phase 18F-FDG myocardial PET/CT might be useful for the diagnosis of ischemia.