Experience of virtual bronchoscopy at a district general hospital

Intoduction: Limitations of 2-dimensional axial CT scanning (ACT) include inability to visualise endobronchial disease and assess patency distal to an airway obtruction (1). Virtual bronchoscopy (VB) is a 3-dimensional endoluminal tracheobronchial reconstruction that allows navigation through the airways (2). Current data on the exact role of VB are sparse. Aim: To review the experience of using a new imaging modality with respect to the frequency, timing, indications and value of VB compared to CCT and Fibre Optic Bronchoscopy (FOB). Methods: We at Whipps Cross Hospital reviewed the VB, ACT and FOB findings in all patients who had VB. ACT images were aquired using an IGE HiSpeed LX/i scanner with 5mm collimation. VB and multiplanar reconstructions were aquired with 3-mm collimation using a GEAdvantage Windows Workstation. Data regarding indication for VB, timing relative to FOB and information aquired compared to ACT or FOB were recorded. Results: 13 patients underwent VB in an 8-month period during which time 234 FOB were performed. VB was performed before and after FOB in 6 and 4 patients respectively. FOB was not done in 3 patients. Indications: ■ Patients initially unfit or too ill for FOB (n=6) ■ Assessment of airways distal to an obtruction (n=2) ■ Evaluation for endobronchial tuberculosis (n=1) ■ Patient on warfarin (n=2) ■ Evaluation of the larynx after trauma (n=1) ■ Poorly tolerated FOB (n=1). Additional information conveyed by VB over ACT: ■ Visualisation of airways distal to an airway obstuction in 4 patients thereby allowing consideration for stenting ■ Demontrating an endobronchial lesion in 1 patient ■ Excluding an endobronchial lesion in 1 patient unfit for FOB. In the 8 patients who had FOB and VB the findings concurred in all patients. The main advantage of FOB was making a histological diagnosis in 4 patients. Conclusion: VB is a useful complementary imaging modality in selected patients. The negative predictive value of a normal VB needs to be determined in a prospective study.