High ¹⁸F-fluorodeoxyglucose uptake in positron emission tomography-computed tomography is associated with emphysema...

Pulmonary emphysema on computed tomography (CT) is a risk factor for all-cause mortality in individuals with and without airflow limitation. The aim of this study was to assess whether ¹⁸F-fluorodeoxyglucose (FDG) lung uptake on positron emission tomography (PET)/CT is associated with emphysema progression in participants who currently smoke and previously smoked.

This single-centre retrospective observational study included participants who repeatedly underwent intensive cancer screening with unenhanced chest CT and semiquantitative ¹⁸F-FDG PET/CT between January 2015 and July 2020. The 15th percentile point (Perc15) and volume-adjusted (VA)-Perc15 on CT were used to assess the degree of emphysema in the participants with at least 2 years of follow-up data. Multiple regression analysis was performed with changes in Perc15 and VA-Perc15 as dependent variables, including the median of the standardised uptake value (SUV) corrected for lean body mass and tissue fraction effects (cSUV_TF-median) as explanatory variables.

We evaluated 2112 participants (1502 male; mean±sd age 59±10 years; 395 currently smoking, 820 previously smoked; 1958 no emphysema, 152 mild emphysema, two moderate emphysema on visual CT inspection). The median follow-up duration was 1470 (interquartile range 1330-1705) days. Higher cSUV_TF-median, higher Perc15 or VA-Perc15 at baseline and older age were associated with annual decreases in Perc15 or VA-Perc15 among the participants who currently or previously smoked.

Semiquantitative FDG uptake was independently associated with longitudinal emphysema progression in both of the participants who currently and previously smoked. Semiquantitative PET/CT may provide useful information for early intervention in participants at high risk for emphysema progression.