Tissue Fraction Correction and Visual Analysis Increase Diagnostic Sensitivity in Predicting Malignancy of Ground-Glass Nodules on [18F]-FDG PET/CT: A Bi-Centre Retrospective Study

Abstract

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 (SUVmax) 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 SUVmax and tissue fraction corrected SUVmax (SUVmaxTF) were in order of adenocarcinoma > MIA > AIS (p = 0.033 and 0.018, respectively). SUVmaxTF was significantly higher than SUVmax 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 SUVmaxTF than in SUVmax (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.

Prone position PET/CT is useful in reducing gravity-dependent opacity-related [18F]fluorodeoxyglucose uptake

“…We also measured the tissue fraction corrected SUV mean (SUV-TF mean ) via the previously described method suggested by Lambrou et al to exclude the air fraction of the lung because [ 18 F]FDG is not distributed in the air [7]. Using this method, the SUV-TF mean can be calculated by measuring the SUV mean and HU of the lung ROI [15].…”