Dual-layer spectral detector CT: predicting the invasiveness of pure ground-glass adenocarcinoma

To investigate the clinical application of novel dual-layer spectral detector computed tomography (CT) for differentiating the invasiveness of pure ground-glass nodules (pGGNs).A total of 42 patients with 43 pGGNs, who underwent preoperative dual-layer spectral detector CT and were identified by pathology, were evaluated retrospectively. The nodules were divided into two groups: minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (IA). Lesion inhomogeneity was observed visually on the iodine density map. Normalised iodine concentrations (NICs) in the arterial and venous phases and the effective atomic number (Zeff), electron density (ED), and the ED-Zeff ratio in the plain, arterial and venous phases were obtained. The maximum diameter and CT attenuation of the lesion in the plain phase were measured. Receiver operating characteristic (ROC) curves were used to analyse the accuracy of spectral CT quantitative parameters in predicting the invasiveness of lung adenocarcinoma manifesting as pGGNs.There were significant differences in the maximum diameter, CT attenuation value, ED and the ED-Zeff ratio in three phase, Zeff in the plain phase, and inhomogeneity between the two groups. Lesion inhomogeneity (odds ratio [OR] = 48.672, p=0.019) and the ED-Zeff ratio (OR=6.908, p=0.030) in the plain phase were independent predictors for diagnosing IA manifesting as pGGNs.Novel dual-layer spectral detector CT can indicate the invasiveness of pGGNs. Lesion inhomogeneity and the ratio of the ED to Zeff in the plain phase can serve as very specific discriminators of IA manifesting as pGGN.