Visual assessment of 18F-FDG metabolic spatial distribution improves the differential diagnosis of indeterminate pulmonary nodules and masses with high FDG uptake

Abstract

Purpose The aim of this study was to evaluate the value of visual analysis of 18 F-fluorodeoxyglucose ( 18 F-FDG) metabolic spatial distribution (V-FMSD) in diagnosis of indeterminate pulmonary nodules and masses with high 18 F-FDG uptake. Methods A total of 301 patients with indeterminate pulmonary nodules or masses who undergone 18 F-FDG positron emission tomography/computed tomography (PET/ CT) imaging were studied retrospectively. The characteristics of 18 F-FDG metabolic spatial distribution (FMSD) of proximal and distal regions of the lesion were visually analyzed using a 5-point scoring system. The sensitivity, specificity, accuracy and area under receiver operating characteristic curve (AUC) were compared between V-FMSD and conventional PET/CT methods for diagnosis of hypermetabolic indeterminate pulmonary nodules and masses. Results The V-FMSD results showed that 180 (92.8%) malignant lesions’ scores were ≥ 3 and 78 (72.9%) benign lesions’ scores were ≤ 2. It indicated that the FMSD in the proximal region of malignant lesions was significantly higher than that of the distal region, and the FMSD in the proximal region of benign lesions was significantly lower than that of the distal region. The specificity of V-FMSD was 72.9%, which was obviously higher than the maximum standard uptake value (SUVmax) (0%, P < 0.001) and retention index (RI) (26.2%, P < 0.001). The AUC of V-FMSD was 0.886, which was significantly larger than SUVmax (0.626, P < 0.001), RI (0.670, P < 0.001) and PET/CT (0.788, P < 0.05). Conclusions The characteristics of FMSD between pulmonary benign and malignant lesions are different. V-FMSD can be taken as a novel auxiliary marker to improve the diagnostic performance for hypermetabolic indeterminate pulmonary nodules and masses.