Experimental study of 18F-FDG PET/CT imaging and cardiac MRI in diagnosis of radiation-induced myocardial injury in Beagle dogs / 中华核医学与分子影像杂志

ABSTRACT

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 (SUVmean) 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. One-way 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 SUVmean 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.