Optical imaging of hemoglobin oxygen saturation using a small number of spectral images for endoscopic application

Abstract

Abstract. Tissue hypoxia is associated with tumor and inflammatory diseases, and detection of hypoxia is potentially useful for their detailed diagnosis. An endoscope system that can optically observe hemoglobin oxygen saturation (StO 2 ) would enable minimally invasive, real-time detection of lesion hypoxia in vivo. Currently, point measurement of tissue StO 2 via endoscopy is possible using the commercial fiber-optic oximeter T-Stat, which is based on visible light spectroscopy at many wavelengths. For clinical use, however, imaging of StO 2 is desirable to assess the distribution of tissue oxygenation around a lesion. Here, we describe our StO 2 imaging technique based on a small number of wavelength ranges in the visible range. By assuming a homogeneous tissue, we demonstrated that tissue StO 2 can be obtained independently from the scattering property and blood concentration of tissue using four spectral bands. We developed a prototype endoscope system and used it to observe tissue-simulating phantoms. The StO 2 (%) values obtained using our technique agreed with those from the T-Stat within 10%. We also showed that tissue StO 2 can be derived using three spectral band if the scattering property is fixed at preliminarily measured values.

The future of endoscopy: Advances in endoscopic image innovations

“…To overcome this, a technique employing a combination of wavelengths with an imaging system composed of two laser diodes and a color CCD sensor it is possible to produce an oxygen saturation map based on the difference in absorption of oxy-hemoglobin and deoxy-hemoglobin accounting for hematocrit. 64,65 A proof of concept study involving 40 cases (n = 40) with established malignancies of the pharynx, oesophagus and colon illustrated a significant difference in the oxygen saturation map between the neoplastic and non- neoplastic areas in the oesophagus and colon only. These preliminary findings of functional imaging may aid diagnosis, predict response to cancer therapies including the outcomes of clinical trials pending larger scale study.…”

“…These preliminary findings of functional imaging may aid diagnosis, predict response to cancer therapies including the outcomes of clinical trials pending larger scale study. 64,65…”

“…Conventional spectroscopy for hemoglobin absorption has been limited by poor image quality, insufficient spatial information and is time‐consuming. To overcome this, a technique employing a combination of wavelengths with an imaging system composed of two laser diodes and a color CCD sensor it is possible to produce an oxygen saturation map based on the difference in absorption of oxy‐hemoglobin and deoxy‐hemoglobin accounting for hematocrit . A proof of concept study involving 40 cases ( n = 40) with established malignancies of the pharynx, oesophagus and colon illustrated a significant difference in the oxygen saturation map between the neoplastic and non‐neoplastic areas in the oesophagus and colon only.…”

“…A proof of concept study involving 40 cases ( n = 40) with established malignancies of the pharynx, oesophagus and colon illustrated a significant difference in the oxygen saturation map between the neoplastic and non‐neoplastic areas in the oesophagus and colon only. These preliminary findings of functional imaging may aid diagnosis, predict response to cancer therapies including the outcomes of clinical trials pending larger scale study …”

Novel oxygen saturation imaging endoscopy to assess anastomotic integrity in a porcine ischemia model

“…A novel endoscope system EP-0002 for gastroenterological exible endoscopy (FUJIFILM Corporation, Kanagawa, Japan) was used to capture the StO 2 images (Fig. 1) [11,12]. The EP-0002 provides the conventional observation modes of white light imaging (WLI).…”