Ebook Paediatric bronchoscopy (Vol 38): Part 2
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Ebook Paediatric bronchoscopy (Vol 38): Part 2
Chapter 9Priftis KN, Anthracopoulos MB. Eber E. Koumbourlis AC. Weed RE teds): Paediatric Bronchoscopy. Prog Respir Res. Basel. Karger 2010, vol 38. p Ebook Paediatric bronchoscopy (Vol 38): Part 2pp 95-112Virtual Bronchoscopy and Other Three-Dimensional Imaging MethodsMichael B. Anthracopoulosd • tfthymia Alexopoulotf • George c. Kagadisb’Respiratory Unit. Department ol Paediatrics. University Hospital ot Patras, and ^Department ot Medical Physic s. School ol Medicine, University of Patras. Ebook Paediatric bronchoscopy (Vol 38): Part 2Patras, and '2nd Department of Radiology, Attikon University Hospital, Medical School of Athens, Athens. GreeceAbstractFlexible bronchoscopy (FB) is tEbook Paediatric bronchoscopy (Vol 38): Part 2
he only method that permits real time direct visualization and dynamic evaluation of the tracheobronchial system. Multidelector computed tomography (MChapter 9Priftis KN, Anthracopoulos MB. Eber E. Koumbourlis AC. Weed RE teds): Paediatric Bronchoscopy. Prog Respir Res. Basel. Karger 2010, vol 38. p Ebook Paediatric bronchoscopy (Vol 38): Part 2ring. VR, and virtual bronchoscopy. V8) images of the airways. Patient breath holding in suspended inspiration is important but with the new faster scanners volume coverage during quiet breathing can achieve high quality images. I he new imaging techniques offer distinct advantages over rfi that inc Ebook Paediatric bronchoscopy (Vol 38): Part 2lude: accurate mapping of airway compression or stenosis, visualisation OÍ the airway beyond the area of obstruct! on. eval nation of smaller a irwaysEbook Paediatric bronchoscopy (Vol 38): Part 2
. and imaging of parenchymal and mediastinal abnormalities. External VR and VB can delineate congenital defects such as pulmonary underdevelopment speChapter 9Priftis KN, Anthracopoulos MB. Eber E. Koumbourlis AC. Weed RE teds): Paediatric Bronchoscopy. Prog Respir Res. Basel. Karger 2010, vol 38. p Ebook Paediatric bronchoscopy (Vol 38): Part 2luate bronchiectasis and air trapping due to small-airway disease. Newer-generation MDCT scanners can be used to assess dynamic collapse of the airways. Radiation exposure remains a concern in CT; patient- and disease-specif ic dose reduction should be implemented according to the ALARA ("as low as Ebook Paediatric bronchoscopy (Vol 38): Part 2reason ably achievable') principle. Alternative techniques such as magnetic resonance imaging should be considered.c opyrkjhr o 2010 s. Karger AÍX HarEbook Paediatric bronchoscopy (Vol 38): Part 2
dFlexible bronchoscopy (FB) is considered the gold standard for the detection and diagnosis of tracheobronchial disorders in children permitting direcChapter 9Priftis KN, Anthracopoulos MB. Eber E. Koumbourlis AC. Weed RE teds): Paediatric Bronchoscopy. Prog Respir Res. Basel. Karger 2010, vol 38. p Ebook Paediatric bronchoscopy (Vol 38): Part 2 be used to evaluate airway morphology beyond high-grade stenosis of the bronchial lumen 11; chapter 2, this vol., pp. 22-29Ị. Inclinical practice, FB is often combined with computed tomography (CT) scanning of the chest for more comprehensive evaluation of the airways and lung parenchyma.In the las Ebook Paediatric bronchoscopy (Vol 38): Part 2t 20 years, a true revolution in Cl technol ogy has made possible non invasive imaging of the air ways. Conventional stop-and-shool' CT that requiredEbook Paediatric bronchoscopy (Vol 38): Part 2
long scan limes with a single data sei per breath-hold evolved into helical (spiral) CT that reduced acquisition time and minimized misregistration duChapter 9Priftis KN, Anthracopoulos MB. Eber E. Koumbourlis AC. Weed RE teds): Paediatric Bronchoscopy. Prog Respir Res. Basel. Karger 2010, vol 38. p Ebook Paediatric bronchoscopy (Vol 38): Part 2hat employs multiple rows of detectors - currently 16- and 64 slice MDCÍ scanners are widely used, while 128 , 256 and, recently, 320 slice scanners are being actively marketed - along with other technical advancements have made true isotropic imaging of large volumes possible within a few seconds | Ebook Paediatric bronchoscopy (Vol 38): Part 22,3|. MDCT provides continuous and complete sets of raw data that are transferred to a picture-archiving and com munication system or 3-dimensional woEbook Paediatric bronchoscopy (Vol 38): Part 2
rkstation for post processing and analysis. Once the final volumetric data set is obtained, a variety of computer algorithms can be applied to generatChapter 9Priftis KN, Anthracopoulos MB. Eber E. Koumbourlis AC. Weed RE teds): Paediatric Bronchoscopy. Prog Respir Res. Basel. Karger 2010, vol 38. p Ebook Paediatric bronchoscopy (Vol 38): Part 2re explained, in alphabetical order, in the Appendix.Magnetic resonance imaging (MRI) is an attractive alternative to MDCT because of lack of patient exposure to radiation, fewer adverse reactions to intravenous contrast material (due to the use of non-iodine-based contrast materials), inherently hi Ebook Paediatric bronchoscopy (Vol 38): Part 2gher soft tissue contrast and ability to perform functional studies. Its main drawbacks are a considerablyFig. 1. Curved plane minimum intensity projeEbook Paediatric bronchoscopy (Vol 38): Part 2
ction image showing the trachea and major bronchi of a 'l-year-old girl with ring-sling syndrome. There is progressive worsening of tracheal stenosis Chapter 9Priftis KN, Anthracopoulos MB. Eber E. Koumbourlis AC. Weed RE teds): Paediatric Bronchoscopy. Prog Respir Res. Basel. Karger 2010, vol 38. p Ebook Paediatric bronchoscopy (Vol 38): Part 2 requires sedation (and in pro longed examinations general anaesthesia) of young children, inferior spatial resolution of lung parenchyma (even with the mosl current slale-ol'-the-arl MRĨ technology), higher compromise in the presence of metallic devices and a relatively high cost. With technical ev Ebook Paediatric bronchoscopy (Vol 38): Part 2olution, MR1 may one day replace CT in the evaluation of various congenital and acquired lung disorders hut currently it is not commonly used in the eEbook Paediatric bronchoscopy (Vol 38): Part 2
valuation of childhood airway disease [2].Multidetector Computed Tomography Imaging of the AirwaysThe axial images obtained With MDCT contain the entiChapter 9Priftis KN, Anthracopoulos MB. Eber E. Koumbourlis AC. Weed RE teds): Paediatric Bronchoscopy. Prog Respir Res. Basel. Karger 2010, vol 38. p Ebook Paediatric bronchoscopy (Vol 38): Part 2udad extent of disease; (c) difficulty displaying complex 3-dimensional structures and their relationship to the airway; (d) Insufficient representation of airways oriented obliquely (or, even worse, parallel) to the axial plane, and (c) generation of a very large number (MDCT scanners produce hundr Ebook Paediatric bronchoscopy (Vol 38): Part 2ed$)of images that arevery difficult to review.lnessence, 3-dimensionally rendered images are creative software solutions to the challenge of depictinEbook Paediatric bronchoscopy (Vol 38): Part 2
g 3-dimensional data - organized in a 3-dimensional matrix of volume elements (voxels)- on the 2-dimensional surface of a computer monitor composed ofChapter 9Priftis KN, Anthracopoulos MB. Eber E. Koumbourlis AC. Weed RE teds): Paediatric Bronchoscopy. Prog Respir Res. Basel. Karger 2010, vol 38. p Ebook Paediatric bronchoscopy (Vol 38): Part 2ages produced from the original reconstruction process in an orientation other than the one they were originally generated.Four basic postprocessing techniques of the volumetri-cally acquired data are used to enhance imaging of airway anatomy; 2 dimensional multiplanar reformation (MPR), 3 dimension Ebook Paediatric bronchoscopy (Vol 38): Part 2al multiplanar volume reconstruction (MPVR), 3-dimensional shaded-surface display (SSD) and 3-dimensional volume rendering (VR) |2, -1.5|.MultiplanarEbook Paediatric bronchoscopy (Vol 38): Part 2
ReformationMPRs arc 1 -voxel-thick 2-dimensional tomographic sections that are as accurate as axial images. By using dedicated algorithms, they can beChapter 9Priftis KN, Anthracopoulos MB. Eber E. Koumbourlis AC. Weed RE teds): Paediatric Bronchoscopy. Prog Respir Res. Basel. Karger 2010, vol 38. p Ebook Paediatric bronchoscopy (Vol 38): Part 2onchus or a feeding vessel). Precise cross-sectional and longitudinal images can be constructed along central and segmental bronchi, thus allowing ‘lesion oriented’ reformations. MPRs have the advantage of high computational speed, thus incorporating information from a large number of axial frames w Ebook Paediatric bronchoscopy (Vol 38): Part 2hile offering real time images almost simultaneously with the axial sections. Most importantly, they can detect focal narrowing that may be missed wheEbook Paediatric bronchoscopy (Vol 38): Part 2
n reading only the axial frames, and the}-can accu lately depict the degree and longitudinal extent of bronchial stenosis. However, the potential decrChapter 9Priftis KN, Anthracopoulos MB. Eber E. Koumbourlis AC. Weed RE teds): Paediatric Bronchoscopy. Prog Respir Res. Basel. Karger 2010, vol 38. p Ebook Paediatric bronchoscopy (Vol 38): Part 2 overlapping of thin axial cuts and careful centring of the trace of the airway lumen of interest with concomitant inspection of the axial images is essential lor their interpretation.Multiplanar Volume ReconstructionMPVR IS a 3-dimensional rendering (volume editing) technique that closely resembles Ebook Paediatric bronchoscopy (Vol 38): Part 2 2-dimensional MPR. It was initially introduced as sliding thin-slab projections’ to improve visualization ofblood vessels and airways by’stacking’sevEbook Paediatric bronchoscopy (Vol 38): Part 2
eral contiguous planar images. The method adds ‘depth’ to the anatomical display of airways and blood vessels and allows smoother and quicker visualizChapter 9Priftis KN, Anthracopoulos MB. Eber E. Koumbourlis AC. Weed RE teds): Paediatric Bronchoscopy. Prog Respir Res. Basel. Karger 2010, vol 38. p Ebook Paediatric bronchoscopy (Vol 38): Part 2 airways or lung parenchyma. For example, the minimum intensity projection takes advantage of the lowest intensity voxels to evaluate airway lumen and areas of uneven attenuation of lung parenchyma (e.g. mild air-trapping), while96Anthracopoulos Alexopoulcxi Kaq^disFig. 2. a Ihree dimensional SSD im Ebook Paediatric bronchoscopy (Vol 38): Part 2age of the patient presented in figure I that demonstrates the long segment concentric carrot like tracheal stenosis (from line A to B) down to the leEbook Paediatric bronchoscopy (Vol 38): Part 2
vel of the carina. I he abnormally wide angle (108”) bifurcation of the trachea and the normally sized main bronchi are clearly shown. An oesophagealGọi ngay
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