Aim: In this study, we explore the potential of ECG-gated 18F-FDG PET to assess LV systolic and diastolic function in a well-stablished rat model of type 2 diabetes.
Introduction: Left ventricular (LV) diastolic dysfunction, defined as a disruption of the normal filling pattern of the ventricle but normal systolic function, is one of the early signs of cardiac involvement in diabetic patients.
Methods: List-mode gated 18F-FDG PET imaging was performed on a rat model of type 2 diabetes (ZDF fa/fa) (n=6) and ZL control rats (n=6) at age of 13 weeks 15–30min after tracer-administration (37MBq) via tail vein under hyperinsulinemic-euglycemic clamp using a dedicated small animal PET system (Siemens Inveon) with ECG signal recording for 20min. List-mode data were sorted and reconstructed into tomographic images of 16 frames per cardiac cycle. PET images were resized to match human-scale pixels. Left ventricular functional parameters were calculated using standard clinical software program (Heart Function View).
Results: Hyperinsulinemic-euglycemic clamp and post mortem tissue analysis demonstrated the development of diabetes in the ZDF rats and of significant myocardial hypertrophy in ZDF rats at age of 13 weeks (994±78mg vs. 871±44mg in ZDF rats vs. ZL controls, p<0.01, respectively). The PET images analysis showed a mild but significant decrease of LV PFR in the ZDF rats (10.4±0.5 vs. 11.8±0.4EDV/s in ZDF rats vs. ZL controls, p<0.001, respectively), whereas no significantly differences concerning LVEF and cardiac output (CO) could be detected between model and control rats (LVEF: 60.0±4.5 vs. 63.7±4.1%, p=0.25 and CO: 90917±14015 vs. 85208±17511μl/min, p=0.90, respectively).
Conclusion: In a rat model of type 2 diabetes, we demonstrated the ability of ECG-gated-18F-FDG PET together with a clinical ventricular edge detection software to assess reliable LV systolic and diastolic parameters and to detect the presence of a diastolic dysfunction in the diabetic rats.