The relationships of the pulmonary arteries to lung lesions aid in differential diagnosis using computed tomography.

The improvement of the resolution of rapid scanning in multidetector computed tomography (CT) has an increased accuracy that allows for the demonstration of the relationship of the pulmonary arteries and lung lesions, even in the peripheral lung. The purpose of this study is to evaluate the relationship between the pulmonary arteries and lung lesions by CT, and to use this relationship to distinguish between benign and malignant lung lesions. The relationships of the lung lesions and the adjacent pulmonary artery were recorded as encasement, displacement, penetration, in the margin, and disconnection. Statistical analyses were then performed to evaluate the relationship of the pulmonary arteries to each lesion with a focus toward the possibility of malignancy and the degree of pulmonary arterial encasement in the lesion. The relationship between the pulmonary arteries and lung lesions had a statistically significant difference between benignancy and malignancy (P < 0.001). Inter-observer agreement was substantial (κ = 0.639; 95% CI: 0.518-0.719). The average degrees of pulmonary arterial encasement in benign and malignant lesions were 52.1% ± 27.3% and 71.8% ± 18.8%, respectively (P = 0.011). The ROC curve showed that the degree of pulmonary arterial encasement had a moderate discriminating ability in diagnosing lung carcinoma, and the area under the curve was 0.738. The best cutoff value was 44.4%. The relationships of the pulmonary arteries to lung lesions and the degree of pulmonary arterial encasement could be used in differentiating benignancy from malignancy not only for central lung lesions but also peripheral lung lesions.