Figure 4.

Female, 57 years old. A U-HRCT target scan (A) shows a vacuole sign in the GGN. A conventional CT target reconstruction (B) shows that the vacuole sign in the nodule is unclearly separated from the surrounding ground-glass opacity. The pathological image indicates tumour infiltration into the matrix leading to the contraction of the elastic tissues of the lung, thus presenting a vacuole sign (normal lung tissue inside the nodule) on CT imaging. The pathological results confirmed the presence of invasive adenocarcinoma (C, HE staining, 200×). U-HRCT, ultra-high-resolution computed tomography; GGN, ground-glass nodule. The arrows point out the lesions.