Virtual Laryngotracheal Endoscopy Based on Geometric Surface Modeling Using Spiral Computed Tomography Data

Abstract

This prospective study describes the clinical utility of virtual endoscopy based on geometric surface modeling of the laryngotracheal lumen. Eighteen children with dyspnea related to either subglottic angioma (n = 5) or laryngotracheal stenosis (n = 13) were included. All patients underwent video-recorded operative endoscopy, spiral computed tomography, and 3-dimensional reconstruction of the laryngotracheal lumen. Modeling was achieved by contour detection on spiral computed tomographic images and reconstruction using a geometric shape-recognition algorithm. The generated surface was used for diagnosis and measurement using interactive and automatic tools. Findings of virtual endoscopy and operative endoscopy were compared. Virtual endoscopy confirmed narrowing of the airway in all cases. In 9 cases, high-grade stenosis prevented complete operative endoscopy, but virtual endoscopy allowed accurate assessment and measurement of the stenosis. The findings of operative and virtual endoscopy were concordant in 9 cases. We conclude that surface modeling provides valuable information for preoperative evaluation of laryngotracheal narrowing. The ability to assess extraluminal anatomy provides a clearer picture of overall disease involvement. In the future, virtual endoscopy will probably be used in conjunction with operative endoscopy for therapeutic decision-making. Noninvasive virtual endoscopy could become an alternative to traditional endoscopy under general anesthesia for therapeutic follow-up.