<s>
Narrow-band	B-Algorithm
imaging	I-Algorithm
is	O
an	O
imaging	O
technique	O
for	O
endoscopic	B-Application
diagnostic	O
medical	O
tests	O
,	O
where	O
light	O
of	O
specific	O
blue	O
and	O
green	O
wavelengths	O
is	O
used	O
to	O
enhance	O
the	O
detail	O
of	O
certain	O
aspects	O
of	O
the	O
surface	O
of	O
the	O
mucosa	O
.	O
</s>
<s>
A	O
special	O
filter	O
is	O
electronically	O
activated	O
by	O
a	O
switch	O
in	O
the	O
endoscope	B-Application
leading	O
to	O
the	O
use	O
of	O
ambient	O
light	O
of	O
wavelengths	O
of	O
415nm	O
(	O
blue	O
)	O
and	O
540nm	O
(	O
green	O
)	O
.	O
</s>
<s>
In	O
gastrointestinal	O
endoscopy	B-Application
,	O
narrow-band	B-Algorithm
imaging	I-Algorithm
has	O
found	O
use	O
in	O
the	O
identification	O
of	O
Barrett	O
's	O
esophagus	O
,	O
in	O
the	O
identification	O
of	O
pit	O
patterns	O
to	O
classify	O
colorectal	O
polyps	O
and	O
tumours	O
,	O
and	O
in	O
the	O
identification	O
of	O
atypical	O
dysplastic	O
cells	O
in	O
the	O
colon	O
of	O
patients	O
with	O
ulcerative	O
colitis	O
.	O
</s>
<s>
Also	O
,	O
in	O
cystoscopy	B-Algorithm
,	O
which	O
is	O
the	O
examination	O
of	O
the	O
urinary	O
bladder	O
with	O
an	O
endoscope	B-Application
,	O
narrow-band	B-Algorithm
imaging	I-Algorithm
is	O
useful	O
in	O
differentiating	O
between	O
benign	O
and	O
malignant	O
cells	O
.	O
</s>
<s>
Alternative	O
methods	O
to	O
improve	O
visualization	O
of	O
the	O
mucosa	O
in	O
endoscopy	B-Application
include	O
chromoendoscopy	B-Algorithm
,	O
confocal	O
microscopy	O
and	O
optical	B-Application
coherence	I-Application
tomography	I-Application
.	O
</s>
