We have developed the white light-emitting diode (LED)-illuminated
endoscopes and previously reported our preliminary experiments with the
prototype LED endoscope in the beagle [1]. Authors in
Nature noted that the white LEDs we employed have been
used for illuminating paintings in fine art museums, as they emit white light
with good color rendering and homogeneous light distribution [2]
[3]. This supports the notion that
these LEDs may also be suitable for use in gastrointestinal endoscopes, as
these instruments must be able to indicate subtle changes in the color and
mucosal structure of the gastrointestinal tract.
The prototype LED endoscopes were based on conventional endoscopes
for studies in humans (Fujifilm Corporation, Saitama, Japan), and white LEDs
were mounted on their tip ([Fig. 1]).
Fig. 1 The prototype
light-emitting diode (LED) endoscope. Two packages of white LEDs and a
charge-coupled device (CCD) were attached to the distal end of the prototype
LED endoscope.
After obtaining Institutional Review Board approval, a patient with
an early gastric carcinoma underwent endoscopy using this new endoscope.
We found that the white LEDs did not provide sufficient illumination
for distant observation in the stomach. However, our prototype LED endoscope
allowed clear visualization of the early gastric cancer by close observation.
The LED endoscope showed a flat lesion, which was located at the anterior wall
of the mid-gastric body and had ill-defined margins accompanied by slightly
reddish or focally pale mucosa ([Fig. 2 a]).
Fig. 2 An image of a
superficially depressed-type early gastric carcinoma that was obtained using
the LED endoscope and a conventional endoscope: a White
LED endoscopic view; b view with indigo carmine dye.
c Conventional endoscopic view; d
view with indigo carmine dye.
Indigo carmine chromoendoscopy emphasized the redness of the lesion
and delineated the demarcation between the cancerous and non-cancerous mucosa
([Fig. 2 b]). These findings corresponded
to those from an examination with a conventional endoscope ([Fig. 2 c, d]). We then subjected the
lesion to endoscopic submucosal dissection using a conventional endoscope.
Pathological evaluation of the excised tissue revealed that the lesion was an
intramucosal differentiated adenocarcinoma and that both its lateral and
vertical margins were free of carcinoma cells ([Fig. 3 a, b]).
Fig. 3 a Macroscopic view of
the resected specimen. The red lines indicate the carcinoma area.
b Pathological analysis of the resected tissue revealed
a well-differentiated adenocarcinoma in the mucosal layer
(× 200).
In conclusion, our observations show that our prototype
LED-illuminated endoscope can clearly visualize early gastric cancers upon
close observation.
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