CT and histopathological characteristics of malignant pure ground-glass nodules less than or equal to 10 mm in diameter

Abstract Objective The aim of this study was to explore the high-resolution computed tomography (HRCT) imaging characteristics of various malignant pure ground-glass nodules (pGGNs) with a diameter ≤ 10 mm and their correlation with the clinical diagnosis of invasive adenocarcinomas (IAs). Data and Methods We retrospectively analyzed patients who underwent thoracoscopic surgery for lung cancer due to malignant pGGNs (diameter ≤ 10 mm) at the First Affiliated Hospital of Zhengzhou University between July 2019 and September 2021. Based on the pathological results, patients were classified into three groups: IAs, microinvasive adenocarcinomas (MIAs) and precursor glandular lesions (PGLs). Univariate and multivariate analyses were performed to identify the independent risk factors, and receiver operating characteristic (ROC) curve analysis was used to calculate the cutoff values. Results A total of 381 patients were enrolled. No significant differences were observed in age, sex, vacuole sign, vascular penetration, tumor-pleura distance, or normal lung tissue density among the three groups (all P > 0.05). Tumor diameter ( P = 0.001) and relative density ( P = 0.001) were independent risk factors for distinguishing PGLs from MIAs, while relative density ( P = 0.001) was the only independent risk factor for distinguishing MIAs from IAs. ROC curve analysis showed that a relative density > 320.5 HU could differentiate IAs from MIAs. Conclusion For malignant pGGNs ≤ 10 mm, MIAs can be distinguished from PGLs when the diameter exceeds 6.015 mm and relative density exceeds 209.5 HU, IAs can be distinguished from MIAs when relative density exceeds 320.5 HU. These findings provide a reference for the pathological diagnosis and surgical strategy selection of small malignant pGGNs.