Description

Diagnostic endoscopy of the human gastrointestinal
(GI) tract aims at satisfying distinct needs, these
being identification, characterisation and histologic
evaluation of suspicious lesions. Three exciting
approaches to achieve this combined objective are
discussed in this issue of CME Gastroenterology:
chromoendoscopy, narrow band imaging (NBI), and
confocal endomicroscopy. Chromoendoscopy is the
most widely studied technique so far and has been
thoroughly evaluated in the upper and lower GI
tracts. It relies on the contrast enhancement between
pathologic and normal mucosa by the application
of intravital dyes, usually via a spraying catheter or
through the working channel of a regular endoscope.
While increasing diagnostic accuracy in Barretts
oesophagus, its place remains a matter of ongoing
debate,as mirrored in competing classification
systems.
1
Chromoendoscopy has been used with
great benefit to unmask and delineate flat lesions. In
the case of ulcerative colitis (UC), chromoendoscopy
has been incorporated into current surveillance
guidelines for appropriately trained endoscopists
2
and its use enhances the detection of squamous
epithelial oesophageal cancer in patients at high risk.
3
Chromoendoscopy therefore is the diagnostic gold
standard in such disease entities. Chromoendoscopy
is easy to perform after adequate training and
classification systems are well established, especially
in the lower GI tract.
4
Drawbacks are that it is time
consuming and that the staining material used can
not be immediately removed so that reverting to
visualising the mucosa without dye in the same
examination is not possible, once staining has been
performed.