differentiating preinvasive from invasive lung adenocarcinoma appearing as part-solid ground-glass nodule using ct value and solid-part diameter

Objectives: 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 methods: 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. results: 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. conclusion: 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.