We read with interest the article by Bak et al in CHEST (January 2016) on quantitative CT scanning analysis of pure ground-glass opacity nodules to predict further CT change. We would like to hear the authors’ comments regarding the following three points. First, why did the authors include three different histological tumor types in this study, namely adenocarcinoma in situ, minimally invasive adenocarcinoma, and invasive adenocarcinoma. Does this mean “ground-glass opacity nodules” were classified into these three pathological types upon examination of resected tumors? Second, although the authors provided a definition for a “central fibrotic lesion” in the Materials and Methods section, a lesion’s “solid component” was not defined anywhere in the article. We are unclear as to the confirmed pathology of the “solid component.” Were there other pathological changes such as intratumor lymphatic, vascular, or pleural alterations that were also considered a “solid component”? Finally, was the “fibrous area” always located at the “central” part of the lesion”? How was its position evaluated?