Exploration In Dynamic Changes In Blood Flow And Function Of Radiation Induced Heart Disease Using ¹³N-ammonia Pet Gated Myocardial Perfusion Imaging In Beagle Dogs With Local Heart Irradiation

Objective:To investigate the value of local myocardial blood flow and global and regional myocardial function parameters in monitoring the dynamic changes of radiation induced heart disease?RIHD?in¹³N-ammonia(¹³N-NH₃)PET gated myocardial perfusion imaging?GMPI?.Methods:Six one-year-old healthy male Beagle dogs underwent examinations of¹³N-NH₃ PET GMPI 1 week before and 3,6 and 12 months after irradiation in the anterior wall of the left ventricle with a single dose of 20 Gy.The results used qualitative and quantitative analysis with Myovation software and QGS/QPS software.Results:Part?Qualitative analysisCompared with baseline,myocardial perfusion increased in the irradiation area after 3months of irradiation,decreased at 6 months after irradiation and further decreased after 12months of irradiation.Part?Quantitative analysis?Global Left Ventricle functionThere was no significant changes of the EDV,ESV and LVEF between baseline and 3months after irradiation.Six months after irradiation,compared with baseline and 3 months after irradiation,there was still no significant difference in EDV,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.?Regional myocardial function?Regional motion parametersCompared with baseline,10%WM?2/20 segments of anteroseptal middle,and apex I?,20%WT?4/20 segments of anterior apical/middle,anteroseptal apical and apex A?were increased?P<0.05?at 3 months after irradiation;15%WM?3/20 segments of anterior apical,anterolateral apical and apex A?,20%WT?4/20 segments of anterior apical/basal,anterolateral middle and apex A?were decreased?P<0.05?at 6 months after irradiation;at12 months after irradiation,35%WM?7/20 segments of anterior middle,anteroseptal apical,inferoseptal middle,inferolateral middle/basal,anterolateral apical and apex A?,45%WT?9/20 segments of anterior apical/middle/basal,inferior apical,inferolateral basal,anterolateral apical/middle and apex A/I?were decreased?P<0.05?.?Regional myocardial perfusion parametersCompared with baseline,10%EDP?2/20 segments of anterior apical and apex A?and15%ESP?3/20 segments of anterior apical/middle and anterolateral apical?were increased?P<0.05?at 3 months after irradiation;15%EDP?3/20 segments of inferolateral apical,anterolateral apical and apex I?and 25%ESP?5/20 segments of inferior middle,inferolateral apical,anterolateral apical/basal and apex A?were decreased?P<0.05?at 6months after irradiation;at 12 months after irradiation40%EDP?8/20 segments of anterior apical,anteroseptal middle,inferoseptal basal,inferolateral apical/basal,anterolateral apical/middle and apex I?and 60%ESP?12/20 segments of anterior apical/middle,anteroseptal apical/basal,inferior middle,inferolateral apical/middle/basal,anterolateral apical/middle/basal and apex A?were decreased?P<0.05?.Conclusion:?¹³N-NH₃ PET GMPI can be used to detect RIHD.Compared with the global LV function,regional myocardial function is more sensitive.Regional myocardial function parameters WM,WT,EDP and ESP may be early indicators of RIHD.?Gated myocardial perfusion imaging can be used to monitor the dynamic development of RIHD,may help RIHD staging and guide clinical treatment.