Benign Solid Pulmonary Nodule
– Trianglular or ovoid
– Circumscribed
– 3-9 mm in diameter
– 3D Ratio = (Greatest axial dimension)/(Greatest superoinferior dimension)
– Benign 3D Ratio > 1.78
Calcification
– Any calcification in a small nodule favors benign cause
– Central, laminar, or dense diffuse are reliably benign
Fat
– DDx: Hamartoma, lipoid granuloma, lipoma
Small, irregular subpleural opacities
– Elderly patients
– Apical regions
Radiology 2005; 237:395-400 AJR 2003; 180:955-964
Risk vs. Benefit
Mayo Clinic CT Screening Trial
< 3mm pulmonary nodule
– 0.2% malignant
4-7 mm pulmonary nodule
– 0.9% malignant
8-20 mm pulmonary nodule
– 18% malignant
>20 mm pulmonary nodule
– 50% malignant
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Suggested Reading
- MacMahon H, Naidich DP, Goo JM, et al. Guidelines for Management of Incidental Pulmonary Nodules Detected on CT Images: From the Fleischner Society 2017. Radiology 2017; 284:228-243.
- Westra SJ, Brody AS, Mahani MG, et al. The Incidental Pulmonary Nodule in a Child – Part 1: Recommendations from the SPR Thoracic Imaging Committee Regarding Characterization, Significance and Follow-Up. Pediatric Radiology 2015; 45:628-633.
- MacMahon H, Austin JHM, Gamsu G, et al. Guidelines for Management of Small Pulmonary Nodules Detected on CT Scans: A Statement from the Fleischner Society. Radiology 2005; 237:395-400.
- Naidich DP, Bankier AA, MacMahon H, et al. Recommendations for the Management of Subsolid Pulmonary Nodules Detected at CT: A Statement from the Fleischner Society. Radiology 2013; 266:304-317.
- de Hoop B, van Ginneken B, Gietema H, et al. Pulmonary perifissural nodules on CT scans: rapid growth is not a predictor of malignancy. Radiology 2012; 265:611-616.
- Takashima S, Sone S, Li F, et al. Small solitary pulmonary nodules (</= 1 cm) detected at population-based CT screening for lung cancer: reliable high-resolution CT features of benign lesions. AJR 2003; 180:955-964.
- Revel MP, Bissery A, Bienvenu M, et al. Are two-dimensional CT measurements of small noncalcified pulmonary nodules reliable? Radiology 2004; 231:453-458.
- Swensen SJ, Jett JR, Hartman T, et al. Screening for lung cancer with CT: Mayo Clinic experience. Radiology 2003; 226(3):756-761.