Introduction Oesophageal cancer (OAC) arises in Barrettt's oesopahgus (BE) and carries a poor prognosis. Early mucosal neoplasia arising in BE can be treated successfully with minimally invasive endotherapy. Fourier transform infrared spectroscopy (FTIR) can detect specific molecules from their unique vibrational absorption spectra in complex materials like human tissue. There is growing literature on it's medical diagnostic uses in the mid-infrared (MID-IR) range of 1800–900 cm−1.
Methods 98 biopsy specimens were obtained from 21 patients undergoing endoscopy for BE surveillance over 3 months. 30 were from squamous epithelium, at least 2 cm above the squamocolumnar junction & remainder from visible BE mucosa. At each site a biopsy was taken for MID-IR analysis. A matched biopsy was taken from the same site for histopathological grading. FTIR spectra were recorded on biopsies at room temperature with a Bruker IFS 66/S spectrometer fitted with a liquid nitrogen-cooled MCT-B detector and an Attenuated Total Reflection silicon microprism. For each spectrum, 1000 interferograms (approximately 2 min accumulation time) were averaged before Fourier transformation. Spectra were converted to second derivatives to remove baseline artefacts and improve signal resolution. An automated programme was used to quantify specific characteristic features and normalise them relative to intensities of the protein amide II band in the same spectrum. The results were used to calculate their correlation with presence of glandular mucosa in BE.
Results Normal squamous mucosa and BE could be differentiated with a sensitivity of 82% and specificity of 96% by analysing variations in the 1180–1000 cm−1 region of second derivative of spectra. Bands in this region responsible for the observed differences arise from variations in levels of glycogen or a related material within the tissues. BE tissue appear to have at least 50% lower concentrations compared to the squamous epithelium.
Conclusion FTIR spectroscopy can accurately differentiate between the columnar mucosa of BE and normal squamous oesophagus. Further work is underway to examine the accuracy of this technique in differentiating different states of dysplasia in BE. IR spectroscopy provides a fast and effective means of detecting BE ex vivo and presents an exciting avenue of future research with a view to incorporating IR spectral analysis into existing technologies to capture real time spectral data at endoscopy to help guide endotherapy to these high risk patients.
Competing interests None declared.
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