Pulmonary malignant focal ground-glass opacity nodules and solid nodules of 3 cm or less: Comparison of multi-detector CT features

Introduction: To evaluate the different multi-detector computed tomography (MDCT) features between pulmonary malignant focal ground-glass opacity (fGGO) nodules and solid nodules of 3 cm or less in diameter. Methods: One hundred and five malignant solid nodules and 48 malignant fGGOs confirmed by pathology were retrospectively analysed with regard to the patient's demographic data, nodule size and MDCT features (shape, margin, interface, internal characteristics and adjacent structure). Differences were analysed using the Fisher exact test or Mann–Whitney U-test. Results: The male to female ratio of patients with malignant solid nodules (60:45) was higher than that with malignant fGGOs (18:30) (P 0.05) or nodule size (P > 0.05). The frequency of irregular shape (4% vs. 21%), spiculation (57% vs. 40%), vacuole sign (11% vs. 52%) and natural air bronchograms (0% vs. 24%) was significantly different between malignant solid nodules and fGGOs. No differences were found in the frequency of lobulation, cusp angle, spine-like process, interface and adjacent structure between the two groups (P > 0.05). Conclusion: Malignant fGGOs and solid nodules showed mostly similar MDCT features. For malignant fGGOs, the frequency of irregular shape, vacuole sign and natural air bronchograms was higher than that in solid nodules, but the frequency of spiculation was lower than that in solid nodules.