3518 USE OF A SHORTER WAVELENGTH AUTOFLUORESCENCE BAND IN BARRETT'S ESOPHAGUS: EFFECT OF DYSPLASIA AND INFLAMMATION.

Abstract

INTRODUCTION: Most work on autofluorescence spectroscopy has been done at emission wavelengths greater than 450 nm. The use of a shorter wavelength emission band was studied in Barrett’s esophagus to observe the effects of dysplasia and inflammation. METHODS: Endoscopically obtained tissue samples were were snap frozen inliquid Nitrogen and stored at -70 Celcius. Prior to measurements, samples were thawed over ice and moistened over phosphate buffered saline at pH 7.4 (PBS). A spectrometer with a Xenon lamp and excitation and emission spectrometers (Shimatzu RF-5301 PC Columbia,MD) was used, with a specially constructed tissue holder placed in its measuring chamber. Tissue was excited below 350 nm and the maximum intensity of an emission peak below 450 nm was measured. Emission intensity in arbitrary units (y-axis) was plotted against wavelength (x-axis). The intensities of intestinal metaplasia (n= 21 ) low grade dysplasia (n= 12) and esophagitis (n= 10)were expressed as a ratio of the corresponding emission intensity of normal squamous mucosa (n= 43) in each patient. RESULTS:The ratios of mean emission intensity ± SE were: 0.63 ± 0.06 (intestinal metaplasia); 2.07 ± 0.26 (low grade dysplasia); 0.62 ± 0.03 (esophagitis). The differences between groups (by ANOVA) were significant (p ≤ 0.0001). CONCLUSIONS: Changes in the intensity of this emission band can differentiate between low grade dysplasia (increased intensity) and inflammation (decreased intensity) when compared to normal squamous mucosa. This emission band also allows columnar epithelium to be distinguished from squamous epithelium. Further work with a hand held portable fiberoptic spectrometer is planned.