Atherosclerotic 18F-FDG and MDP uptake in femoral arteries, changes with age

This study was carried out to evaluate the atherosclerotic changes that occur with age in the femoral arteries. To this end, a group of patients were investigated both by a fluorine-18 fluorodeoxyglucose (F-FDG) PET scan and by a whole-body bone scan.

We included 38 patients (25 women, 13 men, age range: 25-84 years) in this retrospective analysis. All patients underwent an F-FDG PET scan and a Tc-MDP bone scan. The mean interval time between the bone scans and F-FDG PET scans was 1.2±1.6 months. Patients randomly underwent the bone scan or the PET scan first. The patients were subdivided into four groups, with the following age ranges: 25-50, 51-60, 61-70, and 71-84 years. Regions of interest were drawn both over the femoral arteries and the adjacent background (BKG) both on F-FDG PET examinations and MDP bone scans, and the uptake values were calculated. Finally, we calculated and compared the uptake ratios of F-FDG/BKG and MDP/BKG in the four age groups. These ratios were obtained in the exact same way using equal regions of interest and equal drawing positions.

The uptake ratios of F-FDG/BKG in the femoral arteries increased with age in the four age groups (P<0.05). This ratio was the highest in the oldest age group and the lowest in the youngest age group. MDP/BKG in the four age groups also increased with age in numbers. The ratio was the highest in the oldest patients group and the lowest in the youngest patient group, although this increase with age was not statistically significant.

Our results indicate that in the femoral arteries, the uptake ratios of F-FDG/BKG reflects a progression of the inflammatory component of the atherosclerotic activity with age. MDP/BKG in the four age groups in femoral arteries, however, is considered the indicator of severity of the calcification component of atherosclerosis. Calcification in femoral arteries also increased with age, but with a slower progression.