Comparison of Real-Time Virtual and Fiberoptic Bronchoscopy in Diagnosis of Bronchogenic Carcinoma

Abstract

Virtual endoscopy is one of the most recent innovations in the spectrum of post processing techniques. Virtual bronchoscopy is a type of three dimensional reconstruction in which the observation point is placed within the airways to produce an endoscopic like display without the use of endoscope. Seventy three patients with suspected central pulmonary tumors were examined in the radiology department, Manial specialized hospital, Cairo University between October 1999 and September 2001. The patients were subjected to both virtual and fiberoptic bronchoscopy. Virtual studies were calculated and reconstructed from cross sectional images obtained from spiral CT examination of the chest, on a separate work station using a special soft ware. In all patients histopathological diagnosis was obtained either by biopsy or after surgery. A follow up study was performed in 10 patients. The study also included 10 normal subjects to orient oneself with the anatomy to facilitate picking up any the pathological lesions. Fifty cases out of the 73 were pathologically proved as bronchogenic carcinoma. An

excellent overview of the trachea and bronchi up to the 41

and 51

order was obtained in

all cases and the results of the virtual bronchoscopy and fiberoptic bronchoscopy concerning the signs of tumor infiltration including, endobronchial mass, stenosis, obstruction and external indentations were comparable. Although fiberoptic bronchoscopy has the advantage of providing direct cues to colour, vascularity and motility and can detect early tumor infiltration by picking up subtle mucosal changes, virtual bronchoscopy is considered superior in by passing any obstruction thus providing an excellent view distal to an obstructing lesion or stenotic segment which can't be traversed endoscopically. Also, it provided all information surrounding the tracheobronchial tree being reviewed in combination with the cross sectional images thus filling in any diagnostic gaps. The combination of virtual bronchoscopy with the axial CT images had upstaged 19 (38%) of our patients with bronchogenic carcinoma, and hence changed their strategy of treatment. This novel approach can provide information on the position of endotracheal or endobronchial lesions especially when axial CT cuts were negative for parenchymal masses so it is recommended in cases of lung collapse, before proceeding to flexible fiberoptic bronchoscopy. VB can be used in preoperative planning and procedure guidance before palliative stent placement in an airway constricted by a tumor or a scar as well as other interventional procedures including laser photocoagulation and brachy­ therapy. VB will never be able to supplant true endoscopy, especially in evaluation of the airway mucosa or if biopsy is needed for the diagnosis, but VB is likely to prove a valuable auxiliary tool in directing and improving patient care.