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

## TL;DR

This study finds that serum albumin levels affect how [18F]FDG is distributed in the liver and blood pool during PET scans.

## Contribution

The study identifies serum albumin as a significant independent predictor of [18F]FDG activity in the liver and blood pool.

## Key findings

- Liver and blood pool SULmean showed significant positive correlations with serum albumin (r = 0.393 and r = 0.207, respectively).
- Serum albumin was confirmed as an independent variable affecting SULmean in liver and blood pool (p < 0.001 and p = 0.014).
- Low serum albumin may increase false-positive lesion detection in PET scans.

## Abstract

Objective
 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.

Methods
 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.

Results
 A total of 146 patients were included, with their SULmean of the liver and blood pool showing significantly positive correlations with serum albumin (
r
 = 0.393,
p
 < 0.001 and
r
 = 0.207,
p
 = 0.012, respectively). Multiple linear regression analyses confirmed serum albumin as an independent variable on SULmean of the liver and blood pool (
p
 < 0.001 and
p
 = 0.014, respectively).

Conclusion
 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.