Serum Albumin Alters [18F]FDG Activity in the Liver and Blood Pool

<b>Objective</b> This study aims to investigate the correlation between the 2-deoxy-2-[ ¹⁸ F]fluoro-D-glucose ([ ¹⁸ F]FDG) activity of the liver and blood pool, and the serum albumin. <b>Methods</b> A retrospective analysis was conducted on adult patients who underwent [ ¹⁸ F]FDG positron emission tomography/computed tomography at the Nuclear Medicine Unit of a hospital in Hong Kong between January 1, 2023, and March 31, 2023. The mean standardized uptake value normalized to lean body mass (SULmean) was measured in the liver and blood pool. Pearson's correlation analyses between the SULmean of reference regions and serum albumin were performed. Multiple linear regression was used to analyze the effects of serum albumin and other parameters as the independent predictors on SULmean of the reference regions. <b>Results</b> A total of 146 patients were included, with their SULmean of the liver and blood pool showing significantly positive correlations with serum albumin ( <i>r</i> = 0.393, <i>p</i> < 0.001 and <i>r</i> = 0.207, <i>p</i> = 0.012, respectively). Multiple linear regression analyses confirmed serum albumin as an independent variable on SULmean of the liver and blood pool ( <i>p</i> < 0.001 and <i>p</i> = 0.014, respectively). <b>Conclusion</b> Serum albumin alters [ ¹⁸ F]FDG biodistribution in the liver and blood pool. The decrease in liver background activity in patients with low serum albumin may produce a higher false-positive rate of lesion detection, particularly when there is a drop of serum albumin in serial scans. Nuclear medicine physicians should be cautious of image interpretation.