Virtual bronchoscopic navigation in the diagnosis of peripheral pulmonary lesions with, an ultrathin bronchoscope

Graphic data processed from thin-section chest CT images have enabled virtual bronchoscope image (VB), navigation which has also enabled short-time and accurate biopsy of small peripheral lung lesions by ultrathin bronchoscopes. However, the advantages and disadvantages of the diagnostic method have not been fully clarified. The purpose of this study was to clarify limits and problems in diagnostic procedures by virtual bronchoscopic navigation (VBN). Forty-six cases in which peripheral small lung lesions could not be recognized by conventional fluoroscopy were examined. From thin-section CT images, VB images to bronchi reaching lesions directly or as nearly as possible, were processed using workstation software (ZIO M900 Quadra). Then, transbronchial biopsy (TBB) with ultrathin bronchoscope was performed by VBN under real time CT-radiography. The correlation between diagnostic accuracy by these procedures and other factors, such as the size of the lesion, identification of the bronchus involved with the lesion on CT, and ability of forceps to biopsy the lesion were analyzed. In 27 cases, a bronchus directly involved with the lesion could be identified on CT. In 21 (77.8%), a diagnosis of lung carcinoma was established. In all cases in which the lesions were less than 10 mm, neither pulmonary artery nor the involved bronchus could be identified on CT, thus VB for the involved bronchus or accurate biopsy was not successful. Sensitivity, specificity, and diagnostic accuracy of TBB with VBN were 64.1%, 100%, and 65.9%, respectively. TBB with VBN is highly efficient for the accurate biopsy of a small lesion in the periphery of the lung, when the bronchus directly involved with the lesion is identified on CT. The existing virtual endoscopic software which has not been specified to airways is also practical for processing VB. However, this diagnostic method is limited when either the pulmonary artery or the bronchus involved with the lesion cannot be identified. (author)