Virtual bronchoscopy for evaluation of airway disease.

The data presented above indicate that VB is a novel and extremely useful modality for airway evaluation in patients who have benign and malignant disease. VB is noninvasive, with no additional radiation exposure relative to standard CT scans of the chest. Commercial software allows for the interactivity of 2D and 3D images. The ability to examine 2D and 3D anatomic detail from multiple directions enables precise assessment of intraluminal and extraluminal pathology. The authors' experience indicates that VB is a superb modality for assessing the length of airway stenoses and ascertaining airway patency distal to these lesions (Fig. 6). As such, VB has proven to be extremely useful for determining the feasibility of endobronchial procedures such as dilations, stent placements, and laser ablation of endobronchial tumors. Ferretti et al [27] observed that VB is an excellent noninvasive means for long-term monitoring of tracheobronchial stents. Furthermore, the authors have found VB useful for guiding the bronchoscopic evaluation of patients who have intermittent hemoptysis secondary to lesions in peripheral airways. The 3D anatomic detail provided by VB has proven useful for assessing the feasibility of lung-sparing procedures in patients who have limited pulmonary reserve and for sequentially evaluating treatment response in patients who have inoperable disease. Currently, the main limitation of VB pertains to its inability to evaluate the mucosal surface of the respiratory tract reliably. Although form can be detected, mucosal color, irregularity, or friability cannot be assessed. As such, VB cannot be used for routine surveillance of patients at high risk of developing airway malignancies. The development of novel aerosolized contrast agents or spectroscopic techniques that can discriminate benign versus malignant mucosal tissues might enhance the sensitivity and specificity of VB for the detection of preinvasive cancers within the respiratory tract.