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It is not possible to examine the whole surface of the colon in the
endomicroscopic mode. In patients with ulcerative colitis, it is therefore
important to combine endomicroscopy with chromoendoscopy. Panchromoendoscopy
with either methylene blue or indigo carmine is a valid diagnostic tool for
improving the diagnostic yield of intraepithelial neoplasia using the
“SURFACE” recommendations. Chromoendoscopy can reveal circumscribed
lesions, and chromoscopy-guided confocal laser endomicroscopy can be
used to predict intraepithelial neoplasias with a high degree of accuracy. Targeted biopsies of relevant lesions can therefore be taken, and
rapid confirmation of neoplastic changes using confocal laser endoscopy
during colonoscopy may lead to significant improvements in the clinical
management of patients with ulcerative colitis. In 41 patients with long-term
ulcerative colitis who were in clinical remission, endomicroscopy in
conjunction with methylene blue-aided panchromoendoscopy was used for
surveillance. Chromoendoscopy with methylene blue did not lead to any
interference with the laser scanning system.
A total of 14596 confocal images from 464 different locations (369
inconspicuous areas, 95 circumscribed lesions) were compared with the
histological results from 1392 biopsies. Sixtyseven of 95 circumscribed
lesions were only visible after chromoendoscopy with methylene blue.
Different cellular structures (epithelial and blood cells), capillaries, and
connective tissue limited to the mucosal layer were identified by confocal
microscopy. Due to the pharmacokinetic properties of fluorescein,
nuclei could not be seen. However, the presence of neoplastic changes
(sensitivity 94.4 %, specificity 95.6 %, accuracy 99.3 %) and inflammation
were predictable with a high degree of accuracy.
In the first randomized trial of endomicroscopy (Kiesslich et al.,
Gastroenterology 2007), 153 patients with long-term
ulcerative colitis who were in clinical remission were randomly assigned at
a ratio of 1 : 1 to undergo either conventional colonoscopy or
panchromoendoscopy using 0.1% methylene blue in conjunction with
endomicroscopy to detect intraepithelial neoplasia or colorectal cancer.
Circumscribed lesions in the colonic mucosa detected by chromoendoscopy were
evaluated with endomicroscopy for cellular and vascular changes in
accordance with the confocal pattern classification for predicting
neoplasia. Targeted biopsies from the areas examined were taken and
histologically graded according to the World Health Organization and new
Vienna classification.
In the standard colonoscopy group, randomized biopsies every 10 cm between
the anus and cecum were taken, as well as targeted biopsies of visible
mucosal changes. The primary outcome analysis was a histological diagnosis
of neoplasia. Using chromoendoscopy in conjunction with endomicroscopy (80
patients, average examination time 42 min), significantly more
intraepithelial neoplasia was detected (19 versus 4 cases; P=0.007) than
with standard colonoscopy (73 patients, average examination time 31 min).
Endomicroscopy revealed different cellular structures (epithelial and blood
cells), capillaries, and connective tissue limited to the mucosal layer. A
total of 5580 confocal images from 134 circumscribed lesions were compared
with the histological results from 311 biopsies. The presence of neoplastic
changes was predicted with a high degree of accuracy (sensitivity 94.7 %,
specificity 98.3 %, accuracy 97.8%). |
