الفهرس 
Anatomy Of LarynxOnly 14 pages are availabe for public view
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Abstract
Conventional endoscopy allows direct visualization of mucosa and
can be used for biopsy. It is however, invasive and requires sedation, and
endoscopic assessment depends on the operator’s experience. More
importantly, it may not be possible to progress beyond a stenosis or
obstruction, thus hampering complete assessment of the lesion. In
addition, viewing is limited to the lumen, restricting transmural
evaluation. In contrast, virtual laryngoscopy is non-invasive and uses
two-dimensional computed tomography to create three-dimensional
endoscopic simulation with a number of advantages. It can be used to
view the distal aspect of obstructing lesions or stenosis which a
conventional endoscope cannot pass through. All viewing directions are
possible. With appropriate software, the transmural extent of a neoplasm
and surrounding structures can be demonstrated. (Yuling et al., 2007)
While there are several advantages of virtual laryngoscopy, there
are a number of disadvantages. It has the drawback of radiation exposure,
although excellent contour visualization is possible, mucosal irregularities
and vascularity are not depicted. In addition, it does not allow biopsy, and
cannot be used for contact examination of blood vessels unlike
endoscopy. Combining the two techniques, and viewing virtual
laryngoscopic images during endoscopy, a synergistic effect may be
obtained, thus facilitating three-dimensional interpretation. (Wang et al.,
2001 )
Virtual endoscopy is quick to perform and shows anatomical
detail similar to conventional endoscopy. With multi-detector CT and
improving computer technology, reconstructions will become quicker and detail will improve. It is particularly useful for obtaining views from
below an obstructing lesion or stenosis, or in the occasional patient who
will not tolerate examination. However, its current role is in imaging
patients with an impassable obstruction, in order to provide detail distal to
this. It also has potential for improving pre-operative planning and
staging for head and neck pathology. (Yuling et al., 2007)
In conclusion; the larynx is perhaps the area in the human body
that is visualized most often via endoscopy. Virtual laryngoscopy (VL)
would complement conventional laryngoscopy and prove to be especially
useful for examinations in patients having stenosis and congenital defects.
It would also be useful in patients who are unfit for general anesthesia. In
our opinion, VE-based visualization of the larynx and upper airway
would offer numerous benefits over conventional laryngoscopy, including
providing unconventional internal and external views of the airway
anatomy and the subglottic cavity in patients with infection,
inflammation, and neoplasia of the lumen. Although VL holds promise
for some clinical applications, the technique is limited by the quality and
speed of algorithms used for the reconstruction and navigation within the
3D laryngeal cavity.