Quantification of Regional Murine Ozone-Induced Lung Inflammation Using [18F]FDG MicroPET/CT Imaging

Abstract

Purpose Ozone (O3) is a highly potent and reactive air pollutant, which is formed from human-related activities. It has been linked to acute and chronic respiratory diseases in humans by inducing inflammation. Our studies have found evidence that 0.05 ppm of O3, within the threshold of air quality standards, is capable of inducing acute lung injury. This study was undertaken to examine O3-induced lung damage using [18F]FDG (Fluorodeoxyglucose) microPET/CT imaging in wild-type mice. [18F]FDG is a known PET tracer for inflammation.Methods Sequential [18F]FDG microPET/CT imaging was performed at baseline (before O3 exposure), immediately following 2 h of 0.05 ppm O3 exposure (0 h), at 24 h and at 28 h post-exposure. The images were quantified to determine spatial standard uptake values of [18F]FDG in relation to tissue density and compared with baseline values.Results Immediately after O3 exposure, we detected a 72.21 ± 0.79% increase in lung [18F]FDG uptake ratio when compared to baseline measures. At 24 h post-O3 exposure, the [18F]FDG uptake becomes highly variable (S.D. in FDG = 0.0005174 units) with a 42.54 ± 0.33% increase in lung [18F]FDG compared to baseline.Conclusion We have developed a microPET/CT imaging protocol to quantify regional lung uptake of [18F]FDG to understand lung response to O3 exposure.