Dhar A et al. (2006) Elastic scattering spectroscopy for the diagnosis of colonic lesions: initial results of a novel optical biopsy technique. Gastrointest Endosc 63: 257–61

Currently, it is impossible to distinguish accurately between normal and abnormal tissue with colonoscopic evaluation alone. ELASTIC SCATTERING SPECTROSCOPY (ESS) is an optical technique that has been shown to have high sensitivity and specificity in the diagnosis of breast cancer and in the detection of esophageal lesions in vivo. The technique is sensitive to morphologic changes at the cellular and subcellular level; the differential scattering of light by normal and abnormal tissue leads to the generation of different spectral signatures. Researchers in the UK have assessed ESS for the diagnosis of colonic abnormalities in 45 consecutive patients; 483 spectra were generated from 138 colonic sites.

For differentiating between normal tissue and all abnormalities, the sensitivity of ESS was 92% and the specificity was 82%. For cancer detection, sensitivity was 80% and specificity 86%; for colitis detection, sensitivity and specificity were 77% and 82% respectively. Sensitivity and specificity values of between 75% and 88% were obtained for distinguishing between various colonic abnormalities.

ESS equipment is inexpensive, compact and portable, and is compatible with white-light colonoscopy. The authors point out, however, that a combination of imaging techniques might offer more accuracy than any single method. Although ESS is currently a point measurement technique, the authors say that it should be possible to develop the technology to image larger areas.