[Evaluation of tracheobronchial lesions with spiral CT: comparison between virtual endoscopy and bronchoscopy]

The aim of this study is to describe the scanning parameters for virtual bronchoscopy in the evaluation of the tracheobronchial tree and to compare the results of this examination with the endoscopic findings.

27 patients with tracheobronchial neoplasms suspected at preliminary clinical and chest film findings or postoperative follow-up for malignant disease were evaluated with spiral CT of the chest and bronchoscopy. Virtual endoscopy was performed on the pulmonary volume involved by the lesion, using narrow axial images (thickness 2 mm, table index 3 mm, reconstruction index 1 mm.) so as to obtain MPR, MIP and 3D reconstructions with 3D Endo Vew program (Philips Medical System, Eindhoven, Holland). We compared these reconstructions and the findings the normal spiral CT scanning with the corresponding endoscopic examinations.

In all patients we were able to study the lobar and segmental bronchi in all patients and in 2 we also evaluated the subsegmental bronchi. 25 lesions in 23 patients were shown by virtual endoscopy (8 occlusions, 8 stenosis, 5 compressions, 3 flogosis with endobronchial mucus, 1 bronchocele) and in 4 patients the examinations were negative. The bronchoscopy was negative in 4 patients and positive in 23 patients with 25 lesions, but we had agreement in 23/27 patients (85,1%). In 2 patients virtual endoscopy showed the lesions in a different bronchus compared to bronchoscopy. In one patient we interpreted the obstruction as neoplastic instead of mucus inside the bronchi and in the last patient bronchoscopy was not performed due to his old age and the virtual endoscopy showed total obstruction of a segmental bronchus.

The results show that virtual endoscopy can study the tracheobronchial tree as far as the segmental bronchi, and sometimes also the subsegmental bronchi and the bronchi below a closed obstruction. In addition, it can evaluate the extraluminal location of the lesions. For these reasons virtual endoscopy provides a road map for bronchoscopy as a guide for transbronchial biopsy and for endobronchial treatment planning. The limitation of this technique is its inability to evaluate the mucosal surface and distinguish flogosis from neoplastic lesions by biopsy. It can be used however in the postoperative follow-up both for cancer and transplant, when immediate biopsy is not necessary.