[Virtual endoscopy of the upper, central and peripheral airways with multirow detector CT]

Virtual endoscopy of the upper, central and peripheral airways (virtual laryngoscopy or virtual bronchoscopy) produces endoluminal images similar to those of fiberoptic endoscopy. In particular, virtual endoscopy is useful for the assessment of endoluminal tumor extent and tracheobronchial stenosis. Especially since the introduction of multirow detector CT, high-resolution virtual-endoscopic images of the airways can be reconstructed. Either surface rendering or volume rendering can be used for realistic depiction of the airways. Semitransparent color-coded volume rendering is advantageous, because adjacent structures can be displayed in addition to endoluminal views. A major advantage of virtual endoscopy over fiberoptic endoscopy is its non-invasiveness. With virtual endoscopy, even a high-grade stenosis is passable, enabling evaluation of the distal airways. Disadvantages are its inability to depict mucosal color and to perform therapeutic maneuvers. In comparison to other CT display modes, virtual endoscopy allows a more realistic assessment of tracheobronchial stenosis than axial CT slices and multiplanar reformats. Virtual endoscopy of the airways can be used complementary to fiberoptic endoscopy before tracheotomy, stent implantation or lung resection and for post-operative follow-up. In the future, virtual airway endoscopy will be increasingly applied for interactive virtual reality guidance of airway procedures such as bronchoscopy and surgery.