Abstract
To evaluate the utility of the relationship between peripheral pulmonary nodules (PPN) and the drainage bronchi, thin-slice computed tomography (CT) was used to study 44 patients with PPN less than 30mm in diameter. There were 24 patients with lung cancer and 20 patients with non-malignant lesions. Thin-slice CT images were examined by an extended scale (window level : -600, window width : 1900) and a slice thickness 2mm, using a high resolution image. The patients were divided into two groups. One group included 31 (70%) cases (17 lung cancers, 14 non-malignant lesions) with a fourth- to sixth-order bronchus sign. Another group included 13 cases (seven lung cancers, six non-malignant lesions) with no bronchial appearance. Transbronchial biopsy (TBB) showed lung cancer in 14 (82%) of 17 patients in whom a bronchial appearance was seen on CT and in only two (29%) of seven patients in whom it was no seen. The difference was statistically significant (p<0.001). Conversely, in non-malignant lesions, no significant correlation was found between the TBB yield and the relationship of the lesions to the drainage bronchi. Our results suggest that the bronchus sign on thin-slice CT is valuable in predicting the success of transbronchial biopsy. The presence of a bronchial appearance on thin-slice CT may be useful in determining if the workup should include transbronchial biopsy in patients with peripheral small lesions.
