Grading Airway Stenosis Down to the Segmental Level Using Virtual Bronchoscopy
Noninvasive imaging of the airways has made remarkable progress in the past decade. The introduction of multirow detector CT scanners has made it possible to acquire high-resolution images of the upper, central, and segmental airways within a short acquisition time. The CT scan data can be reformatted into three-dimensional images to create virtual bronchoscopic renderings that closely resemble the images obtained from flexible broncho-scopy. in detail
Virtual bronchoscopy has been applied increasingly for the evaluation of the airways, especially to detect benign and malignant airway stenosis. Its potential for depicting tracheobronchial stenosis has been demonstrated with single-detector helical CT scanning, but the z-axis resolution has been limited by scan collimation if complete scan acquisition of the chest was to be achieved within a single breath-hold. A previous study demonstrated that virtual bronchoscopy with multirow detector CT scanning enables the reduction of scan collimation to produce high z-axis resolution despite a short scan time. Virtual bronchoscopy was found to be highly accurate in the detection of central airway stenosis and to correlate closely with flexible bronchoscopy in grading tracheobronchial stenosis.
Preliminary evidence indicates that multirow detector CT scanning enables virtual bronchoscopic evaluation of peripheral airways such as the segmental and subsegmental bronchi if adequate scanning parameters are used. In the present study, we evaluated the diagnostic accuracy of CT virtual bronchoscopy in detecting and grading stenoses of both the central and segmental bronchi using flexible bronchoscopy as the standard of reference.
Materials and Methods
This blinded retrospective trial comprised 20 consecutive patients (age range, 50 to 81 years; mean age, 61 years; 15 men and 5 women). Eight of these patients also had been included in a previous study. Three of these eight patients had new follow-up CT scans in which both the central and segmental bronchi were evaluated for the first time. In the other five patients, the CT scan data fulfilling the inclusion criteria for the present study were evaluated for the first time at the segmental level and were reevaluated blindly for the central airways.