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Purpose: The purpose of our study was to assess the CT patterns and prognostic value of ground-glass attenuation in nodular bronchioloalveolar carcinoma (BAC)., Method: We retrospectively reviewed CT examinations of 22 patients with 24 nodular BACs who underwent surgery. CT and pathologic findings were analyzed and correlated with postoperative course of disease., Results: We detected five patterns of ground-glass attenuation associated with nodular BAC: pure ground-glass nodule (n = 1), ground-glass nodule with superimposed lymphangitis (n = 1), nodule with mixed areas of ground-glass attenuation and consolidation (n = 2), ground-glass halo around nodule (halo sign) (n = 3), and nodule associated with a plurisegmental area of ground-glass attenuation (n = 1). Two patients with the halo sign and a third patient with a plurisegmental area of ground-glass attenuation rapidly developed diffuse pulmonary disease by bronchogenic spread and died a few months after surgery., Conclusion: Our series demonstrates that focal BAC may progress to diffuse pulmonary involvement by bronchogenic spread. The presence of a large area of ground-glass attenuation associated with a nodular BAC might be the CT sign of an aggressive biologic behavior. In these cases there is a high likelihood for diffuse disease to develop from bronchogenic spread.

To investigate the value of computed tomography (CT) for depicting the relationship between carcinomatous solitary pulmonary nodules and the bronchial tree and predicting the results of various bronchoscopic biopsy techniques, the authors retrospectively reviewed CT scans from 27 consecutive patients with solitary pulmonary nodules associated with a positive bronchus sign. All patients underwent bronchoscopy and transbronchial biopsy. Macroscopic demonstration of the tumor-bronchi relationship was obtained in 18 patients. Five basic types of tumor-bronchus relationships were identified with CT: (a) bronchus cut off by the tumor, (b) bronchus contained within the tumor, (c) bronchus compressed by the tumor, (d) thickening and smooth narrowing of the bronchus leading to the tumor, and (e) thickening and irregular narrowing of the bronchus leading to the tumor. The diagnostic yield of transbronchial forceps biopsy and bronchial brushing was significantly higher in nodules characterized by a cut-off or contained bronchus. Transbronchial needle aspiration was performed in six patients, and results were positive in five, all of whom had a compressed or thickened bronchus. These results confirm that yield of transbronchial biopsy is determined by the type of tumor-bronchus relationship and the biopsy technique performed.

To evaluate the utility of the CT bronchus sign in making a choice between transbronchial biopsy (TBB) and transthoracic needle aspiration (TTNA) as the first diagnostic procedure in a patient with a solitary pulmonary nodule (SPN), we reviewed the results of TBB and TTNA in 26 patients who had a bronchogenic carcinoma less than 3 cm, studied with thin-section CT. The patients were divided into two groups. Group 1 included ten cases with a third- to fifth-order bronchus sign. Group 2 included two cases with a sixth-order bronchus sign and 14 cases with absence of a bronchus sign. TBB was performed in all the patients; conversely, TTNA was carried out in 22 patients. In group 1, TBB gave a diagnostic yield in eight (80 percent) of ten patients, while TTNA was positive in three (42 percent) of seven patients (p > 0.05). Conversely, in group 2, results of TBB were normal in all the patients, while TTNA gave a diagnosis in 10 (66 percent) of 15 patients (p < 0.05). We think that TBB should be considered the method of choice in diagnosing SPNs associated with a third- to fifth-order bronchus sign; conversely, TTNA is more useful than TBB in diagnosing SPNs in the presence of a more peripheral bronchus sign or with the absence of a bronchus sign. In conclusion, we suggest routine evaluation with thin-section CT of each SPN to optimize diagnostic management.

The bronchus sign on CT represents the presence of a bronchus leading directly to a peripheral pulmonary lesion. We investigated the value of this sign in predicting the results of transbronchial biopsy and brushing in 33 consecutive cases of proved peripheral bronchogenic carcinoma studied with thin-slice CT (2-mm-thick sections). The bronchus sign was seen on CT in 22 patients and was absent in 11. Transbronchial biopsy and brushing showed peripheral carcinoma in 13 (59%) of 22 patients in whom the bronchus sign was seen on CT and in only two (18%) of 11 patients in whom it was not seen. The difference is statistically significant (Fisher's exact test, p = .029). When analyzed by the order of involved bronchus, a 90% success rate of transbronchial biopsy and brushing was found in patients in whom the bronchus sign was seen at a fourth-order bronchus (p = .01). This compared with a success of 33% when the bronchus sign was seen at fifth-, sixth-, or seventh-order branches. Our results suggest that the bronchus sign at a fourth-order bronchus is valuable in predicting the success of transbronchial biopsy and brushing. The presence of the sign on CT may be useful in determining if the workup should include transbronchial biopsy and brushing or transthoracic needle aspiration in patients with peripheral lung lesions.