Dynamic changes in blood flow and function of the heart using 13N-NH3 PET gated myocardial perfusion imaging in Beagle dogs after local heart irradiation / 中华核医学与分子影像杂志

ABSTRACT

Objective To investigate the value of local myocardial blood flow and myocardial function parameters in monitoring the dynamic changes of radiation induced heart disease (RIHD) using 13NNH3 PET gated myocardial perfusion imaging(GMPI).Methods Six healthy male Beagle dogs underwent 13N-NH3 PET GMPI 1 week before irradiation and 3,6 and 12 months after irradiation in the anterior wall of the left ventricle with a single dose of 20 Gy.Global myocardial function parameters including left ventricular ejection fraction (LVEF),end-diastolic volume (EDV),end-systolic volume (ESV),and regional myocardial function parameters including wall motion (WM),wall thickening (WT),end-diastolic perfusion (EDP),end-systolic perfusion (ESP) before and after irradiation were compared by repeated measures analysis of variance and paired t test.Results There were no significant changes between EDV,ESV and LVEF at baseline and those at 3 months after irradiation.EDV at 6 months after irradiation still had no change,compared with baseline value and EDV at 3 months after irradiation,but ESV was increased and LVEF was decreased.Twelve months after irradiation,ESV was further expanded,LVEF was further reduced,and EDV began to increase (F values:20.974-177.846,all P＜0.05).Compared with the baseline,WM,WT,EDP and ESP were increased in 10％(2/20),20％(4/20),10％(2/20) and 15％(3/20) of myocardial segments at 3 months after irradiation (t values:14.446-672.315,all P＜0.05);those parameters were decreased in 15％(3/20),20％(4/20),15％(3/20) and 25％(5/20) of myocardial segments at 6 months after irradiation (t values:18.171-723.156,all P＜0.05),and were decreased in 35％(7/20),45％(9/20),40％(8/20) and 60％ (12/20) of myocardial segments at 12 months after irradiation (t values:14.783-711.259,all P＜0.05).Conclusions 13N-NH3 PET GMPI could be used to detect RIHD early and monitor the dynamic development of RIHD.Compared with the global left ventricular function parameters,regional myocardial function parameters (WM,WT,EDP and ESP) are more sensitive,which may be served as the early monitoring indicators for RIHD.