Diagnostic Effectiveness of Virtual Bronchoscopy

This study will evaluate a new technique for examining the air passages of the lungs called "virtual bronchoscopy." It involves using computed tomography (CT) images of the chest to generate a 3-dimensional model of the walls of the trachea and bronchi (airway passages). This non-invasive method lets doctors see small masses and areas of narrowing in the passages without having to do surgery or pass a tube through them. Patients with diseases of the air passages who are enrolled in an NIH clinical trial may participate in this study, which requires having a CT scan. The patient lies on a table that slowly slides into a hole in a donut-shaped X-ray machine (the scanner). Patients may have to hold their breath several times during the procedure. Some patients may be given an injection of a contrast agent through a catheter (thin tube) placed in an arm vein to improve visibility of abnormalities. Patients may also be asked to breathe oxygen through nasal prongs to allow them to hold their breath longer. The procedure usually takes 15 to 20 minutes.