Longitudinal imaging of murine atherosclerosis with 2-deoxy-2-[¹⁸F]fluoro-D-glucose and [¹⁸F]-sodium fluoride in genetically modified Apolipoprotein E knock-out and wild type mice

In a longitudinal design, four arterial segments in mice were followed by positron emission tomography/computed tomography (PET/CT) imaging. We aimed to determine how the tracers reflected the development of atherosclerosis via the uptake of 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) for imaging inflammation and [¹⁸F]-sodium fluoride (Na[¹⁸F]F) for imaging active microcalcification in a murine model of atherosclerosis. Apolipoprotein E knock-out (ApoE) mice and C57 BL/6NtaC (B6) mice were divided into four groups. They received either normal chow (N = 7, ApoE mice and N = 6, B6 mice) for 32 weeks or a high-fat diet (N = 6, ApoEHFD mice and N = 9, B6HFD mice) for 32 weeks. The mice were scanned with [¹⁸F]FDG and Na[¹⁸F]F using a dedicated small animal PET/CT scanner at three timepoints. The tracer uptakes in four aortic segments (abdominal aorta, aortic arch, ascending aorta, and thoracic aorta) were measured and reported as SUV_max values. The uptake of [¹⁸F]FDG (SUV_max: 5.7 ± 0.5 vs 1.9 ± 0.2, 230.3%, p = < 0.0001) and Na[¹⁸F]F (SUV_max: 9.6 ± 1.8 vs 4.0 ± 0.3, 175%, p = 0.007) was significantly increased in the abdominal aorta of ApoEHFD mice at Week 32 compared to baseline abdominal aorta values of ApoEHFD mice. [¹⁸F]FDG uptake in the aortic arch, ascending aorta and the thoracic aorta of B6HFD mice at Week 32 showed a robust resemblance to the abdominal aorta uptake whereas the Na[¹⁸F]F uptake only resembled in the thoracic aorta of B6HFD mice at Week 32 compared to the abdominal aorta. The uptake of both [¹⁸F]FDG and Na[¹⁸F]F increased as the disease progressed over time, and the abdominal aorta provided a robust measure across mouse strain and diet. Therefore, it seems to be the preferred region for image readout. For [¹⁸F]FDG-PET, both B6 and ApoE mice provide valuable information and either mouse strain may be used in preclinical cardiovascular studies, whereas for Na[¹⁸F]F -PET, ApoE mice should be preferred.