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Pulmonary lesions detected in population-based CT screening for lung cancer: reliable findings of benign lesions.

PURPOSE
To identify the characteristics of benign pulmonary lesions in order to reduce false-positive rates in screening computed tomography (CT) and in order to reduce frequency of follow-up high-resolution CT (HRCT).


MATERIALS AND METHODS
We evaluated 238 screening-detected benign lesions and 23 screening-detected lung cancers for 12 characteristics: spiculation, well-defined margin, concave margin, polygonal shape, notch/lobulation, solid component, ground-glass opacity (GGO), air bronchogram, cavity, bubble-like appearance, pleural indentation, and vascular convergence. We also measured the lesion diameters to set a threshold for benign lesions. We tested combinations of these characteristics to differentiate benign lesions from lung cancers.


RESULTS
By using certain combinations of the characteristics that showed statistically significant differences between benign lesions and lung cancers, benign lesions could be extracted without contamination by lung cancer in screening CT, when the combination included solid component as a positive finding. In HRCT, more than 80% of the benign lesions could be extracted without contamination by lung cancer when the combination included GGO as a negative finding.


CONCLUSION
It seems possible to reduce the frequency of follow-up HRCT to establish a diagnosis of benign lesions using certain combinations of the characteristics of benign nodules.