The development of optical spectroscopy in the diagnosis of colorectal disease

• Main Author: Wood, James John
• Published: University of Bristol 2015
• Subjects: 616.3
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.690896

Background: Histopathology provides the gold standard assessment of colorectal biopsies. Numerous techniques for improving lesion detection at colonoscopy and classification are emerging. This thesis applied two complementary methods of vibrational spectroscopy which can provide a unique molecular 'fingerprint'; Raman and Fourier Transform Infrared (FTIR). Hypotheses: 1. An 'in-house' constructed flbreoptic Raman probe which fits through the accessory channel of a colonoscope can classify different colorectal pathologies. 2. FTIR spectroscopy can classify colorectal pathologies within tissue sections and determine biochemical composition. Methods: Biopsy samples were collected at colonoscopy, snap frozen and later thawed for experimentation. Point Raman spectra were measured from biopsies using the probe system. Subsequent formalin fixation enabled histopathological comparison. Principal component analysis (PCA) and linear discriminant analysis (LOA) with leave one out cross validation (LOOCV) correlated Raman spectra with histopathology. FTIR spectral maps were measured across tissue sections using an infrared imaging system in transmission mode. Contiguous haemotoxylin and eosin stained sections were compared by a pathologist. Spectra from epithelia were classified using PCA, LOA and LOOCV. Reference spectra from purchased biochemicals were measured. Dot product and ordinary least squares analyses estimated the relative biochemical signal contribution.