Use of an Endoscope Compatible Probe to Detect Colonic Dysplasia with Fourier Transform Infrared (FTIR) Spectroscopy

摘要

FTIR spectroscopy is sensitive to the molecular composition of tissue and has the potential to identify pre-malignant tissue (dysplasia) as an adjunct to endoscopy. We demonstrate collection of mid-infrared absorption spectra with a silver halide (AgCl0.4Br0.6) optical fiber and use spectral pre-processing to identify optimal sub-ranges that classify colonic mucosa as normal, hyperplasia, or dysplasia. We collected spectra (n = 83) in the 950 to 1800 cm⁻¹ regime on biopsy specimens obtained from human subjects (n = 37). Subtle differences in the magnitude of the absorbance peaks at specific wavenumbers were observed. The best double binary algorithm for distinguishing normal-versus-dysplasia and hyperplasia-versus-dysplasia was determined from an exhaustive search of spectral intervals and pre-processing techniques. Partial least squares discriminant analysis was used to classify the spectra using a leave-one-subject-out cross-validation strategy. The results were compared with histology reviewed independently by two gastrointestinal pathologists. The optimal thresholds identified resulted in an overall sensitivity, specificity, accuracy, and positive predictive value of 96%, 92%, 93%, and 82%, respectively. These results indicated that mid-infrared absorption spectra collected remotely with an optical fiber can be used to identify colonic dysplasia with high accuracy, suggesting that continued development of this technique for the early detection of cancer is promising.