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Advanced Imaging in Endoscopy
data are collected at a scan rate of 0.8 frames/second (1,024x512 pixels) targeted biopsies of relevant lesions can be performed and rapid
or 1.6 frames/second (1,024x1,024 pixels). The optical slice thickness is prediction of neoplastic changes by confocal laser endoscopy during
7µm with a lateral resolution of 0.7µm. The field of view is 500x500µm. colonoscopy may lead to significant improvements in the clinical
The range of the z-axis was 0–200µm below the surface layer. Confocal management of UC patients. Different cellular structures (epithelial
images can be generated simultaneously with endoscopic images.
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A and blood cells), capillaries and connective tissue limited to the
fluorescent contrast agent is used to achieve high-contrast images using mucosal layer could be identified by confocal microscopy. Due to the
confocal endomicroscopy. Potentially suitable agents are fluorescein, pharmacokinetic properties of fluorescein, nuclei could not be seen.
acriflavine, tetracycline or cresyl violet. The contrast agents can be However, the presence of neoplastic changes (sensitivity 94.4%;
applied systemically (fluorescein) or topically (all others) by using a specificity 95.6%; accuracy 99.3%) and inflammation could be
spraying catheter. The most common dye used to date is fluorescein. predicted with high accuracy.
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The confocal endoscope can be handled similarly to a standard Conclusion
endoscope. After the application of a contrast dye (e.g. fluorescein, The newly developed high-resolution/high-definition and magnifying
systemically), the distal tip of the endoscope is placed in gentle contact endoscopes offer features that allow more and new mucosal details to
with the mucosa and the position of the focal plane within the be seen, which can ideally be used to better recognise flat colorectal
specimen adjusted using the buttons on the endoscope control body. lesions. High-definition and high-resolution endoscopy is commonly
In every region of interest images from the surface to deeper parts of used in conjunction with chromoendoscopy or digital filters to further
the mucosal layer can be obtained and stored digitally in a specific characterise identified lesions. The analysis of mucosal surface and
folder associated with the site of collection. Targeted biopsies are vessel details can be used to predict final histology. However, most
possible due to the proximity of the working channel and the recently confocal laser endomicroscopy can be used to explore in vivo
endomicroscopic window at the distal tip of the endoscope, which histology during ongoing colonoscopy (confirmation technology).
allows the position of the confocal scanner on the tissue to be seen via
the conventional video endoscopic view. All of these newly available techniques have to be used in a distinct
clinical algorithm (recognition–characterisation–confirmation). The new
The confocal laser endoscope can be used routinely for screening detailed images seen with different kinds of endoscopic technologies
and surveillance. Suspected lesions can be examined in a targeted are the beginning of a new era where sophisticated optical analysis will
fashion by placing the endomicroscopic window onto the lesion. lead to fewer but more targeted biopsies. n
Confocal images can be graduated according to cellular and vascular
changes. The images correlated well with conventional histology after
Ralf Kiesslich is Head of the Endoscopic Unit in the First
targeted biopsies. In the first prospective trial 13,020 confocal images
Department of Medicine of the Johannes Gutenberg
from 390 different locations (256 inconspicuous areas; 134 University (JGU) in Mainz. His main research interests
circumscript lesions) were compared with histological data from
are new imaging modalities and new treatment options
in gastrointestinal (GI) endoscopy. Dr Kiesslich serves on
1,038 biopsies. Subsurface analysis during confocal laser endoscopy
the Council of the German Society of Gastroenterology,
allowed detailed analysis of cellular structures. The presence of and he is leading the section of research on GI
neoplastic changes could be predicted by using the new developed
endoscopy. He is also a member of the Editorial Boards
of Gut, Endoscopy and Digestive Diseases. He has
confocal pattern classification with high accuracy (sensitivity 97.4%;
published extensively in high-ranking journals and has received several prizes, such as
specificity 99.4%; accuracy 99.2%).
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the Don Wilson Award from the American Society of Gastrointestinal Endoscopy
(ASGE) and the Martin Guelzow Award from the German Society of Gastroenterology.
Dr Kiesslich graduated from JGU in 1996, and in the same year completed his
In addition, a combination of chromoendoscopy and confocal laser
doctorate at JGU. He joined the First Department of Medicine at JGU in 2000 after
endoscopy facilitates surveillance in UC. Chromoendoscopy unmasks finishing his internship at St Hildegardis Hospital in Mainz. He is board-certified in
circumscript lesions and confocal laser endomicroscopy can be used
internal medicine and gastroenterology.
to predict intra-epithelial neoplasias with high accuracy. Thus,
1. Nelson DB, Block KP, Bosco JJ, et al., High resolution and lesions of the colorectal mucosa, Gastrointest Endosc, aided chromoendoscopy for the detection of
high magnification endoscopy. Guidelines: Technology 2008;68(4 Suppl.):S3–47. intraepithelial neoplasia and colon cancer in ulcerative
Status Evaluation Report, Gastrointest Endosc, 2000;52: 8. Rembacken BJ, Fujii T, Cairns A, et al., Flat and depressed colitis, Gastroenterology, 2003;124:880–88.
864–6. colonic neoplasms: a prospective study of 1000 14. Sada M, Igarashi M, Yoshizawa S, et al., Dye spraying and
2. Rex DK, Helbig CC, High yields of small and flat adenomas colonoscopies in the UK, Lancet, 2000;8:1211–14. magnifying endoscopy for dysplasia and cancer surveillance
with high-definition colonoscopes using either white light 9. Machida H, Sano Y, Hamamoto Y, et al., Narrow-band in ulcerative colitis, Dis Colon Rectum, 2004;47:1816–23.
or narrow band imaging, Gastroenterology, 2007;133(1):42–7. imaging in the diagnosis of colorectal mucosal lesions: a 15. Rutter MD, Saunders BP, Schofield G, et al., Pancolonic
3. Canto MI, Staining in gastrointestinal endoscopy: the pilot study, Endoscopy, 2004;36:1094–8. indigo carmine dye spraying for the detection of dysplasia
basics, Endoscopy, 1999;31:479–86. 10. Kaltenbach T, Friedland S, Soetikno R, A randomised in ulcerative colitis, Gut, 2004;53:256–60.
4. Kudo S, Tamura S, Nakajima T, et al., Diagnosis of tandem colonoscopy trial of narrow band imaging versus 16. Marion JF, Waye JD, Present DH, et al., Chromoendoscopy-
colorectal tumorous lesions by magnifying endoscopy, white light examination to compare neoplasia miss rates, targeted biopsies are superior to standard colonoscopic
Gastrointest Endosc, 1996;44:8–14. Gut, 2008;57(10):1406–12. surveillance for detecting dysplasia in inflammatory bowel
5. Konishi K, Kaneko K, Kurahashi T, et al., A comparison of 11. Aschenbeck J, Adler A, Yenerim T, et al., Narrow-Band disease patients: a prospective endoscopic trial, Am J
magnifying and nonmagnifying colonoscopy for diagnosis Versus White-Light HDTV Endoscopic Imaging for Gastroenterol, 2008;S03(9):2342–9.
of colorectal polyps: a prospective study, Gastrointest Screening Colonoscopy: A Prospective Randomized Trial. 17. Kiesslich R, Burg J, Vieth M, et al., Confocal laser
Endosc, 2002;57:48–53. Gastroenterology, 2009;136(2):410–6.e1, quiz 715. endoscopy for diagnosing intraepithelial neoplasias and
6. Soetikno RM, Kaltenbach T, Rouse RV, et al., Prevalence of 12. Pohl J, Lotterer E, Balzer C, et al., A randomized colorectal cancer, in vivo, Gastroenterology, 2004;127:706–13.
nonpolypoid (flat and depressed) colorectal neoplasms in multicenter trial on computed virtual chromoendoscopy 18. Kiesslich R, Goetz M, Lammersdorf K, et al.,
asymptomatic and symptomatic adults, JAMA, 2008;299(9): versus standard colonoscopy with targeted indigocarmine Chromoscopy-guided endomicroscopy increases the
1027–35. chromoscopy, Gut, 2009;58(1):73–8. diagnostic yield of intraepithelial neoplasia in ulcerative
7. Kudo S, Lambert R, Allen JI, et al., Nonpolypoid neoplastic 13. Kiesslich R, Fritsch J, Holtmann M, et al., Methylene blue colitis, Gastroenterology, 2007;132(3):874–82.
EUROPEAN GASTROENTEROLOGY & HEPATOLOGY REVIEW 25
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