FDG PET imaging as a potential modality for detecting atherosclerotic lesions in the major arteries

Abstract

Background: The aim of this study was to determine whether the atherosclerotic lesions in large arteries can be detected by FDG-PET, and to define the changes that occur over time in different age groups. Methods: We evaluated the presence of FDG vascular uptake in 78 consecutive subjects (48 male 30 female; age 7 - 80) who underwent whole-body PET scans for the assessment of non-cardiovascular disorders. They were divided into 4 groups according to their age, 0–20 yrs (n=11); 21–40 yrs (n=20); 41–60 yrs (n=26) and 61–80 yrs (n= 21). We recorded the presence of atherosclerotic FDG uptake in the ascending, arch, descending and abdominal aorta, also in the iliac and femoral arteries. The SUVs was calculated for the most metabolically active atherosclerotic lesions in each of the anatomic segments noted above. Results: Among 78 subjects in all 4 groups, 70 were noted to have increased uptake in at least one segment of the large vessels. The mean and SD of SUVs in four groups for the different arteries are given in the table below. SUVs were significantly different for all age groups (p<0.05) except for iliac arteries (p=0.08). In the abdominal aorta in only 6 patients FDG uptake was detected of which 4 belonged to the fourth group. Patient n = 70 Ascending Aorta Arch of Aorta Descending Aorta Iliac Artery Femoral Artery Gp1 (n = 9) 1.16 ± 0.62 1.3 ± 0.45 1.37 ± 0.48 - - Gp2 (n = 16) 1.74 ± 0.38 1.75 ± 0.18 1.98 ± 0.24 1.36 ± 0.10 1.17 ± 0.26 Gp3 (n = 24) 2.06 ± 0.54 2.10 ± 0.47 2.11 ± 0.48 1.45 ± 0.25 1.27 ± 0.23 Gp4 (n = 21) 2.23 ± 0.44 2.24 ± 0.43 2.23 ± 0.44 1.72 ± 0.54 1.57 ± 0.26 Conclusion: These data indicate that atherosclerotic changes shows FDG uptake which increases with age in the large arteries. The probable explanations for the FDG uptake are the presence of macrophages in the atherosclerotic plaques. However, the possibility of smooth muscle uptake as a possible explanation for such uptake can not be ruled out. Further studies are underway to determine the bases for the observations made in the study.