Differentiating Preinvasive from Invasive Lung Adenocarcinoma Appearing as Part-Solid Ground-Glass Nodule Using CT Value and Solid-Part Diameter

To evaluate the differentiating roles of computed tomography (CT) for invasive adenocarcinomas (IACs) of the lung from preinvasive lesions or minimally invasive adenocarcinomas (MIAs) manifesting as part-solid ground-glass nodules (GGNs).
Patients and All 230 lesions were pathologically confirmed. Their size, CT parameters and morphological features were compared among the three groups. Optimal cut-off values were calculated for parameters with diagnostic value.
The diameter of the GGN lesion and the maximum diameter of the solid part, as well as CT values of the ground-glass part and the solid part differed significantly among the three groups. Cut-off maximum diameter of the solid part was 2.5 and 5.5 mm to differentiate preinvasive vs. MIA and MIA vs. IAC, respectively. Cut-off mean CT value was -581 and -464 hounsfield unit (HU) to differentiate preinvasive vs. MIA and MIA vs. IAC, respectively. Cut-off CT value of the ground-glass part was -675 and -562 HU to differentiate the same three groups. Morphological characteristics such as lobulation, spiculation and air bronchograms were all more likely to occur in invasive lesions.
The mean CT value, CT value of the ground glass part and maximum solid-part diameter of a GGN can help differentiate preinvasive from invasive lung adenocarcinomas.