%0 Book Section %B Medical Imaging Systems Technology %D 2005 %T Techniques in 3D Assessment of Tracheal-Stenosis by the Mean of Spiral Computed Tomography (S-CT) and Their Applications %A Erich Sorantin %A Darius Mohadjer %A Franz Lindbichler %A László Gábor Nyúl %A Kálmán Palágyi %A Bernhard Geiger %E Cornelius T Leondes %X Endotracheal intubation is the most common cause of Laryngo-Tracheal Stenoses (LTS), followed by trauma and prior airway surgery.1–3 In rare cases LTS may have resulted also from inhalation injuries, gastro-esophageal reflux disease, neoplasia and autoimmune diseases like Wegeners granulomatosis or relapsing polychondritis.1,4 In pediatric patients vascular compression of the trachea is a common cause of tracheal indentations.5 Clinical management of these conditions requires information on localization, grade, length and dynamics of the stenosis. Exact LTS information is necessary, since stenoses with a length less than 1.0 cm can be treated by an endoscopic surgery.6,7 Besides Fiberoptic Endoscopy (FE), which represents the gold standard for airway evaluation, imaging modalities like conventional radiography, fluoroscopy, tracheal tomograms, Magnetic Resonance Imaging (MRI) and above all Spiral Computed Tomography (S-CT) are an essential part of the clinical work.1,8 S-CT and the recent introduction of multislice imaging allows volumetric data acquisition of the Laryngo–Tracheal Tract (LTT) during a short time span. Decreased motion artifacts and increased spatial resolution form the basis for high quality post processing.9,10 The improved performance of today's workstations permits the use of sophisticated post processing algorithms even on standard hardware like personal computers. Thus real time 3D display and virtual endoscopic views (virtual endoscopy) are just one mouse click away. Other algorithms compute the medial axis of tubular structures like airways or vessels in 3D, which can be used for the calculation of 3D cross sectional profiles for better demonstration of caliber changes.11 Thus display of S-CT axial source images is moving rapidly to 3D display. Moreover, established network connections within and between institutions allows telemedical cooperation. Web technologies offer an easy to use way for information exchange. The objective of this paper is to present an overview on 3D display and quantification of LTS as well as to provide information how these results can be presented and shared with the referring physicians on the hospitals computer network. This article is structured in seven parts; namely: S-CT data acquisition for LTS imaging; selected 3D image post processing algorithms; 3D display; Virtual endoscopy; Objective LTS degree and length estimation using LTT 3D — cross-sectional profiles; Intranet applications; and a conclusion is drawn in the final section. %B Medical Imaging Systems Technology %I World Scientific %C Singapore %P 61 - 80 %8 2005/// %G eng