Multispectral light scattering endoscopic imaging of esophageal precancer

Abstract

Esophageal adenocarcinoma is the most rapidly growing cancer in America. Although the prognosis after diagnosis is unfavorable, the chance of a successful outcome increases tremendously if detected early while the lesion is still dysplastic. Unfortunately, the present standard-of-care, endoscopic surveillance, has major limitations, since dysplasia is invisible, often focal, and systematic biopsies typically sample less than one percent of the esophageal lining and therefore easily miss malignancies. To solve this problem we developed a multispectral light scattering endoscopic imaging system. It surveys the entire esophageal lining and accurately detects subcellular dysplastic changes. The system combines light scattering spectroscopy, which detects and identifies invisible dysplastic sites by analyzing light scattered from epithelial cells, with rapid scanning of the entire esophageal lining using a collimated broadband light beam delivered by an endoscopically compatible fiber optic probe. Here we report the results of the first comprehensive multispectral imaging study, conducted as part of routine endoscopic procedures performed on patients with suspected dysplasia. In a double-blind study that characterized the system’s ability to serve as a screening tool, 55 out of 57 patients were diagnosed correctly. In addition, a smaller double-blind comparison of the multispectral data in 24 patients with subsequent pathology at locations where 411 biopsies were collected yielded an accuracy of 90% in detecting individual locations of dysplasia, demonstrating the capability of this method to serve as a guide for biopsy.

Factors influencing the accuracy for tissue classification in multi spectral in-vivo endoscopy for the upper gastro-internal tract

“…Therefore, the lower accuracy of 68% in our older study 22 might be caused by the in-vivo setting. This is also a reason that current systems such as multi spectral light scattering devices 33 are only tested on the biopsies. Even if the results in this study seem to be obvious, they still show that the multi spectral imaging process can be simulated by the means of MCS.…”

Novel endoscopic optical diagnostic technologies in medical trial research: recent advancements and future prospects

“…Moreover, primary scattering centers of tissue are the extracellular matrix consisting of a collagen fiber network and intracellular structures with sizes smaller than optical wavelengths [ 125 ]. And larger intracellular structures, such as the nuclei, also scatter light, with their relative contribution on increasing the backscatter direction [ 126 ].…”

Quantitative phase and polarization imaging through an optical fiber applied to detection of early esophageal tumorigenesis

“…8,9 Fluorescence lifetime imaging has been proposed for endoscopic red-flag imaging but typically requires costly pulsed laser sources and gated detectors. 10 A number of label-free optical biopsy modalities have shown promise to improve identification of dysplasia, including optical coherence tomography (OCT), 11,12 angle-resolved lowcoherence intereferometry, 13 elastic scattering spectroscopy, 14 and Raman spectroscopy. 15 While many red-flag approaches now employ "chip-on-tip" cameras, optical biopsy is usually achieved with the introduction of an optical fiber endomicroscope through the accessory channel of the red-flag endoscope.…”

“…19 Polarimetric imaging measurements of diattenuation, retardance, and circularity can also be modified by scattering, as well as by the higher concentrations of optically anisotropic molecules, such as collagen, abundant in tumors. 20 Light scattering spectroscopy has shown promise for detecting dysplasia using phase and polarization information but interrogates only a narrow field-of-view; 14 this limitation is partially mitigated by OCT, which uses lateral scanning mechanisms and can be integrated into capsule endoscopes, 14 but interpretation of the resulting cross-sectional images remains challenging. 16 Adding phase or polarization sensitivity to chip-on-tip distal sensors is also difficult, as standard cameras do not capture this information; specialist cameras for the purpose are expensive and not easily miniaturized.…”