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Endoscopy
Figure 3: Digital Chromoendoscopy (I-Scan) and In 2003 the first randomised, controlled trial was published to test
Chromoendoscopy of a Flat Adenoma
whether chromo- and magnifying endoscopy might facilitate early
detection of intraepithelial neoplasia in patients with UC by using
A B
magnifying chromoendoscopy.
13
One hundred and sixty-five patients
with long-standing UC were randomised in a 1:1 ratio to undergo
conventional colonoscopy or colonoscopy with chromoendoscopy
using 0.1% methylene blue. Circumscript lesions in the colon were
evaluated according to a modified pit-pattern classification. In the
chromoendoscopy group, there was a significantly better correlation
between the endoscopic assessment of degree and extent of colonic
inflammation and the histopathological findings compared with the
C D
conventional colonoscopy group. More targeted biopsies were
possible, and significantly more intraepithelial neoplasias were
detected in the chromoendoscopy group (32 versus 10). Using the
modified pit-pattern classification (pit-pattern I–II: endoscopic
prediction non-neoplastic; pit pattern III–V: endoscopic prediction
neoplastic), both the sensitivity and the specificity for differentiation
between non-neoplastic and neoplastic lesions were 93%. This trial
was seen by Bernstein as an exciting development in the field of
dysplasia surveillance colonoscopy. The ability of the dye technique to
distinguish neoplastic from non-neoplastic lesions to enhance
A: High-definition white light imaging.
detection of more dysplastic lesions in flat mucosa is a potentiallyB: I-Scan V: increased vasculature is displayed with intense blue.
C: I-Scan P: pattern analysis can be achieved. Villous architecture can be identified.
major advance in dysplasia surveillance (see Figure 4).
D: Chromoendoscopy with indigo carmine leads to better visualisation of tissue detail.
Figure 4: Colitis-associated Dysplasia and Pseudo
In a large follow-up study with magnifying endoscopy in 886 patients
Polyps Characterised by Chromoendoscopy and with UC, Sada and colleagues
14
found that dysplasia and early cancer
Confocal Laser Endomicroscopy
were characterised by granular or nodular protruding mucosa or by
lowly protruding or flat mucosa, often associated with redness. Dye-
A B
spraying endoscopy was useful for detection. All lesions with intra-
epithelial neoplasias were characterised by staining pattern III–V.
Dysplasia was never found in normal-looking mucosa after staining.
Furthermore, Rutter et al. found no dysplastic tissue in 2,904 non-
targeted biopsies.
15
Taken together, these data suggest that targeted
biopsies after intravital staining will replace random biopsies in the
future. Most recently, Marion et al. found that chromoendoscopy not
C D only increased the diagnostic yield per neoplastic lesion; it also could
show that there is a significant gain for patients having at least one
intra-epithelial neoplasia.
16
In conclusion, magnifying chromoendoscopy is a new valid tool for
improving endoscopic detection of intra-epithelial neoplasia in
patients with long-standing UC. Chromoendoscopy increases the
diagnostic yield of intra-epithelial neoplasia compared with
A: An irregular area can be identified in a patient with long-standing ulcerative colitis using
conventional colonoscopy and biopsy techniques by three- to 4.5-
high-definition endoscopy.
B: Chromoendoscopy can be used to delineate the borders of the lesion. fold, which further suggests that more patients with UC could be
C: Two pseudo polyps are visible.
considered as candidates for colectomy. Differentiation of non-
D: Normal colonic crypts can be visualised in x1,000 magnification in fluorescein-aided
endomicroscopy. There is slightly enlarged cryptal lumen (white arrow) as well as normal neoplastic from neoplastic lesions is possible with a high overall
distribution of goblet cells (yellow arrow), characterising non-neoplastic tissue.
sensitivity and specificity. Thus, the old days when endoscopists were
groaning about too many random biopsies seem to be over and a new
accuracy to chromoendoscopy based on the newly visible vessel era has begun where a few smart biopsies are sufficient for
detail. A recent study dealing with post-processing filters (FICE) surveillance colonoscopy in patients with long-standing UC.
showed similar results.
12
Confocal Laser Endomicroscopy
Ulcerative Colitis Confocal laser endomicroscopy allows subsurface analysis of the
Patients with ulcerative colitis (UC) have a significantly higher risk of intestinal mucosa and in vivo histology during ongoing endoscopy (see
development of colitis-associated colorectal cancer. The growing Figure 4). The components of a confocal laser endoscope are based on
pattern of dysplastic tissue is often multifocal and flat. Thus, integration of a confocal laser microscope in the distal tip of a
significant lesions can be overlooked. Randomised biopsies are conventional video endoscope. During laser endoscopy a single line
recommended but cannot erase the fear of overlooked cancers with laser delivers an excitation wavelength of 488nm and the maximum
severe consequences for the patient. laser power output is ≤1mW at the surface of the tissue. Confocal image
24 EUROPEAN GASTROENTEROLOGY & HEPATOLOGY REVIEW
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