Characterization of hilar lymph node by 18F-fluoro-2-deoxyglucose positron emission tomography in healthy subjects

One hundred and seventy-nine images were collected from healthy subjects who underwent whole-body 18F-fluoro-2-d-deosyglucose positron emission tomography (FDG-PET) for health examination. Images showing visually increased FDG uptake based on a five-point visual scale in the hilar regions were included for analyses. We evaluated the sizes, standard uptake values (SUV), and lesion-to-background (L/B) ratios of the hilar lymph nodes (HLN). Fifty of 179 (28%) subjects had visually increased FDG uptake in the hilar regions with a total of 84 HLN. By a five-point visual scale, 67 out of 84 (79.8%) HLN were grade 2, 16 out of 87 (19%) were grade 3, and 1 out of 84 (1.2%) was grade 4. The average size of the HLN was 1.55 x 1.46 cm. SUV of the HLN ranged from 1.132-2.975 with an average of 1.8 +/- 0.44. L/B ratio of the HLN ranged from 1.05-2.63 with an average of 1.52 +/- 0.39. Twenty-eight % of healthy subjects who underwent whole-body FDG-PET demonstrated visually increased FDG uptake in the HLN. However, all of the 84 HLN had a size < 2 x 2 cm, SUV < 3.0 and L/B ratios < 3.