@inbook {909, title = {New advances for imaging laryngo / trachealstenosis by post processing of spiral-CT data}, booktitle = {Digital (r)evolution in radiology}, year = {2006}, month = {2006///}, pages = {297 - 308}, publisher = {Springer-Verlag}, organization = {Springer-Verlag}, address = {Wien; New York} } @inbook {908, title = {Techniques in 3D Assessment of Tracheal-Stenosis by the Mean of Spiral Computed Tomography (S-CT) and Their Applications}, booktitle = {Medical Imaging Systems Technology}, year = {2005}, note = {doi: 10.1142/9789812701077_0003}, month = {2005///}, pages = {61 - 80}, publisher = {World Scientific}, organization = {World Scientific}, address = {Singapore}, abstract = {Endotracheal intubation is the most common cause of Laryngo-Tracheal Stenoses (LTS), followed by trauma and prior airway surgery.1{\textendash}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{\textendash}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{\textquoteright}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 {\textemdash} cross-sectional profiles; Intranet applications; and a conclusion is drawn in the final section. } } @article {896, title = {Spiral-CT-based assessment of tracheal stenoses using 3-D-skeletonization}, journal = {IEEE TRANSACTIONS ON MEDICAL IMAGING}, volume = {21}, year = {2002}, note = {UT: 000175063900007ScopusID: 0036489382doi: 10.1109/42.996344}, month = {2002///}, pages = {263 - 273}, abstract = {PURPOSE: Demonstration of a technique for three-dimensional (3-D) assessment of tracheal-stenoses, regarding site, length and degree, based on spiral computed tomography (S-CT). PATIENTS AND METHODS: S-CT scanning and automated segmentation of the laryngo-tracheal tract (LTT) was followed by the extraction of the LTT medial axis using a skeletonization algorithm. Orthogonal to the medial axis the LTT 3-D cross-sectional profile was computed and presented as line charts, where degree and length was obtained. Values for both parameters were compared between 36 patients and 18 normal controls separately. Accuracy and precision was derived from 17 phantom studies. RESULTS: Average degree and length of tracheal stenoses was found to be 60.5\% and 4.32 cm in patients compared with minor caliber changes of 8.8\% and 2.31 cm in normal controls (p << 0.0001). For the phantoms an excellent correlation between the true and computed 3-D cross-sectional profile was found (p << 0.005) and an accuracy for length and degree measurements of 2.14 mm and 2.53\% respectively could be determined. The corresponding figures for the precision were found to be 0.92 mm and 2.56\%. CONCLUSION: LTT 3-D cross-sectional profiles permit objective, accurate and precise assessment of LTT caliber changes. Minor LTT caliber changes can be observed even in normals and, in case of an otherwise normal S-CT study, can be regarded as artifacts. }, isbn = {0278-0062} } @inbook {961, title = {New advances for imaging of laryngotracheal stenosis by post processing of spiral-CT data}, booktitle = {Digital (R)Evolution in Radiology}, year = {2000}, month = {2000///}, pages = {275 - 285}, publisher = {Springer-Verlag}, organization = {Springer-Verlag}, address = {Berlin; Heidelberg; New York; London; Paris; Tokyo} }