Changes of aortic FDG uptake and calcification in long-term follow-up PET/CT studies of health screening subjects

Objectives To investigate the changes of aortic FDG uptake and calcification and their relation with atherogenic risk factors in long-term follow-up studies of health screening subjects.

Methods A total of 94 consecutive subjects (72 men, 22 women; age range, 47-85 years, mean age, 57.9 years at initial study) participating in a health check protocol including FDG PET/CT were evaluated retrospectively. All subjects underwent follow-up PET/CT scans 3.0 to 5.8 years (mean 4.1years) after the initial study. We measured FDG uptake (maximum standardized uptake value) and calcium score of the ascending, descending thoracic and infrarenal abdominal aorta.

Results FDG uptake of the whole aorta (FUWA) significantly increased in the follow-up study compared with the initial study (p=0.02). FUWA increased in 60 subjects and decreased in 34 subjects. Glycosylated hemoglobin(HbA1c) (p=0.05), visceral fat area (p=0.05) and subcutaneous fat area (p=0.04) were significantly higher in the increased group than in the decreased group. CSWA increased in 73 subjects and did not change in 21 subjects. Age (p=0.008), smoking habit (p=0.04) and HbA1c (p=0.03) were significantly higher, and low density lipoprotein cholesterol (p=0.01) was significantly lower in the increased group than in the changeless group. Multiple regression analysis for atherogenic risk factors associated with relative change of FUWA per year did not yield significant results, while change of CSWA per year was significantly associated with age and smoking habit. The degree of FDG uptake (p=0.05) and calcium score (p<0.0001) progression was significantly greater in the abdominal aorta than in the thoracic aorta.

Conclusions Our data demonstrates that the progression of vascular inflammation and calcification is associated with different atherogenic risk factors. Also, the progression of vascular inflammation and calcification in the abdominal aorta is significantly faster than in the thoracic aorta