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Int J Clin Exp Pathol 2012;5(9):956-964

Original Article
Normalized autofluorescence imaging diagnostics in upper GI tract: a new method to
improve specificity in neoplasia detection

Ekaterina Krauss, Abbas Agaimy, Alexandre Douplik, Heinz Albrecht, Helmut Neumann, Arndt Hartmann, Ralf Hohenstein, Martin Raithel,
Markus F Neurath, Jonas Mudter

Department of Medicine 1, University of Erlangen-Nuremberg, Ulmenweg 18, D-91054 Erlangen, Germany; Institute of Pathology, University of
Erlangen-Nuremberg, Krankenhausstr.12, 91054 Erlangen, Germany; Medical Photonic Engineering Group, Chair of Photonics Technologies,
Erlangen, Germany; Clinical Photonics Lab, Erlangen Graduate School in Advanced Optical Technologies (SAOT), Erlangen, Germany. *Equal
contributors.

Received August 28, 2012; Accepted October 2, 2012; Epub October 20, 2012; Published October 30, 2012

Abstract: Background and Aims: This study was performed to improve the autofluorescence imaging (AFI) in the upper GI tract by applying a
new method of normalized autofluorescence (NAFI) obtained via tri-modal imaging. Objective: NAFI may provide lower false positive rate to
achieve ultimately better specificity at acceptable sensitivity. Patients and methods: This is a prospective, controlled single-centre study. 18
patients with suspected esophagus or stomach cancer undergoing esophagogastroduodenoscopy (EGD) were enrolled between February
and May 2010. After endoscopy each patient was assigned into one of two groups: (1) non- cancer, including inflammation; (2) cancer group.
EGDs were performed using video white light endoscopy, followed by AFI/NAFI. The targeted biopsy samples were taken from the abnormal
areas as well as from adjacent mucosa. NAFI was compared versus AFI for cancer diagnostics in terms of specificity and sensitivity. Results:
NAFI detected all neoplastic lesions. WLE or NBI detected no additional neoplasia. The AFI displayed mucosal inflammation and carcinomas
of esophagus and stomach as dark red color, the normal mucosa background was displayed as light green. The NAFI didn’t differentiate
inflamed tissue from normal in majority of cases, but in tumorous mucosa, the cancer areas were detected precisely. AFI shows 100%
sensitivity but 50% specificity which correlates with previous literature data. On the other hand, NAFI demonstrated lower sensitivity (88%) but
higher specificity compared to AFI (69%). Conclusions: Measuring the NAFI instead of the AFI was found improving the specificity of cancer
diagnosis. Use of fiber-optic endoscopes to analyze AFI and possible endoscopic and histological sampling error are the main potential
limitations of this method. (IJCEP1208025).

Keywords: Autofluorescence imaging, NAFI, endoscopic tri-modal imaging, esophagogastroduodenoscopy, cancer diagnostic

Address all correspondence to:
Dr. Jonas Mudter
Department of Medicine I
University of Erlangen-Nuremberg
Ulmenweg 18, D-91054, Erlangen,
Germany.
Tel: +49 9131 8545017; Fax: +49 91318535116
E-mail: jonas.mudter@uk-erlangen.de