03434nas a2200193   4500008004100000245012500041210006900166260004100235300001200276520262600288100002002914700002102934700002302955700002802978700002303006700002103029700002603050856016403076       2005                        eng d00aTechniques in 3D Assessment of Tracheal-Stenosis by the Mean of Spiral Computed Tomography (S-CT) and Their Applications0 aTechniques in 3D Assessment of TrachealStenosis by the Mean of S  aSingaporebWorld Scientificc2005///  a61 - 803 aEndotracheal 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.
1 aSorantin, Erich1 aMohadjer, Darius1 aLindbichler, Franz1 aNyúl, László, Gábor1 aPalágyi, Kálmán1 aGeiger, Bernhard1 aLeondes, Cornelius, T  uhttps://home.inf.u-szeged.hu/publication/techniques-in-3d-assessment-of-tracheal-stenosis-by-the-mean-of-spiral-computed-tomography-s-ct-and-their-applications