We investigated the role of [¹⁸F]FDG positron emission tomography/computed tomography (PET/CT) in evaluating ground-glass nodules (GGNs) by visual analysis and tissue fraction correction. A total of 40 pathologically confirmed ≥1 cm GGNs were evaluated visually and semiquantitatively. [¹⁸F]FDG uptake of GGN distinct from background lung activity was considered positive in visual analysis. In semiquantitative analysis, we performed tissue fraction correction for the maximum standardized uptake value (SUV_max) of GGN. Of the 40 GGNs, 25 (63%) were adenocarcinomas, 9 (23%) were minimally invasive adenocarcinomas (MIAs), and 6 (15%) were adenocarcinomas in situ (AIS). On visual analysis, adenocarcinoma showed the highest positivity rate among the three pathological groups (88%, 44%, and 17%, respectively). Both SUV_max and tissue-fraction–corrected SUV_max (SUV_maxTF) were in the order of adenocarcinoma > MIA > AIS (p = 0.033 and 0.018, respectively). SUV_maxTF was significantly higher than SUV_max before correction (2.4 [1.9–3.0] vs. 1.3 [0.8–1.8], p < 0.001). When using a cutoff value of 2.5, the positivity rate of GGNs was significantly higher in SUV_maxTF than in SUV_max (50% vs. 5%, p < 0.001). The diagnostic sensitivity of [¹⁸F]FDG PET/CT in predicting the malignancy of lung GGN was improved by tissue fraction correction and visual analysis.

Purpose: We investigated the role of [¹⁸F]-FDG positron-emission tomography/computed tomography (PET/CT) in evaluating ground-glass nodules (GGNs) by visual analysis and tissue fraction correction.Methods: A total of 40 pathologically confirmed ≥1-cm GGNs were evaluated visually and semi-quantitatively. [¹⁸F]-FDG uptake of GGN distinct from background lung activity was considered positive in visual analysis. In semi-quantitative analysis, we performed tissue fraction correction for the maximum standardised uptake value (SUV_max) of GGN.Results: Of 40 GGNs, 25 (62.5%) were adenocarcinomas, 9 (22.5%) were minimally invasive adenocarcinomas (MIAs), and 6 (15%) were adenocarcinomas in situ (AIS). On visual analysis, adenocarcinoma showed the highest positivity rate among the three pathology groups (88.0%, 44.4%, 16.7%, respectively). Both SUV_max and tissue fraction corrected SUV_max (SUV_maxTF) were in order of adenocarcinoma > MIA > AIS (p = 0.033 and 0.018, respectively). SUV_maxTF was significantly higher than SUV_max before correction (2.4 [1.9–3.0] vs. 1.3 [0.8–1.8], p < 0.001). When using a cut-off value of 2.5, the positivity rate of GGNs was significantly higher in SUV_maxTF than in SUV_max (50.0% vs. 5.0%, p < 0.001).Conclusions: Tissue fraction correction and visual analysis increased the diagnostic sensitivity of [¹⁸F]-FDG PET/CT in predicting malignancy of lung GGN.