Abstract: Objective To explore and analyze the diagnostic efficacy of Philips 64-slice spiral CT in pulmonary nodules of different sizes, so as to promote the application of Philips 64-slice spiral CT. Methods From August 2017 to March 2022, 86 patients with large and small pulmonary nodules were selected for diagnosis and treatment in Beijing Fengtai Hospital of Integrated Traditional Chinese and Western Medicine, included 40 cases of pulmonary nodules with a diameter of ≤ 1 cm (small nodule group), 46 cases of pulmonary nodules with a diameter of 1-3 cm (large nodule group). All patients were examined by Philips 64-slice spiral CT, and the routine CT features, CT values, CT perfusion parameters, nodule malignancy rate and diagnostic value of the two groups were recorded. Results The air bronchus sign, pleural stretch sign, vacuole sign, vascular aggregation sign, lobulation sign, burr sign and other CT features in the large nodule group accounted for 80.43%, 86.96%, 89.13%, 84.78%, 89.13%, 80.43%, which were significantly higher than 30.00%, 35.00%, 45.00%, 52.50%, 35.00%, and 50.00% in the small nodule group (P<0.05). The CT values of the large nodule group were significantly higher than those of the small nodule group (P<0.05). The bronchial artery perfusion value and pulmonary artery perfusion value in the large nodule group were significantly higher than those in the small nodule group (P<0.05), and there was no significant difference in the perfusion index between the two groups (P>0.05). The malignant rate of the large nodule group was 80.43% (37/46), included 20 adenocarcinomas, 13 squamous cell carcinomas, and 4 small cell carcinomas; the malignant rate of the small nodule group was 30.00% (12/40), of which there were 6 cases of adenocarcinoma, 4 cases of squamous cell carcinoma, and 2 cases of small cell carcinoma, there were significant differences in pairwise comparison (P<0.05). Conclusion The application of Philips 64-slice spiral CT in pulmonary nodules of different sizes can reflect the pathological status of the nodules through the imaging morphological features and perfusion characteristics, and has a good diagnostic performance, it can help the qualitative diagnosis of pulmonary nodules of different sizes.

Key words: Philips 64-slice spiral CT, pulmonary nodules, morphological characteristics, perfusion characteristics, diagnostic efficacy, air bronchus sign, pleural traction sign