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Spectroscopy Combined with Optical Polarization for Endoscopy

Final Report Summary - SCOPE (Spectroscopy Combined with Optical Polarization for Endoscopy)

Spectroscopic techniques for detecting reflectance spectroscopy and autofluorescence were originally proposed to be combined with contrast enhancing methods such as polarisation imaging and Laser Speckle Contrast Analysis (LASCA) imaging modalities at a prototype that could fit at a rigid endoscope for aiding diagnostics. The aim was to develop a near real-time imaging tool that could detect the spatial distributions of tissue chromophores such oxy and deoxy haemoglobin and provide spectroscopic information about the haemodynamic and metabolic tissue properties.

In order to make the proposed device more practical in clinical use and facilitate it’s transition into clinical trials and potentially into clinical practice, the development of a flexible endoscope instead of a rigid was incorporated LASCA and polarisation discrimination imaging, observe the spatiotemporal evolution of haemodynamics and to increase image specificity.

The prototype experimental set-up was tested for the first time during four uterine transplant operations in big animal models (sheep), for the purpose of evaluating transplant organ viability. Initial results suggested that this contrast enhancement method could image organ oxygenation and could provide information on physiological parameters such as heart beat rate and breathing rate.
Further improvements of the endoscope were made during the second year to increase the speed of the image acquisition and the synchronisation of the illumination sources with fast detection, which lead to more accurate detection of the haemodynamic measurements and the diagnostics of the physiological parameters.

The fellow performed experiments with tissue mimicking phantoms in order to calibrate the system and measure blood flow accurately in a controlled laboratory environment. She also used various mathematical models of analysing flow by developing more sophisticated custom made image processing software.

The fellow compared the quantitative results from ELASCA with the ones from microscopic setups, that exist in the literature and found that ELASCA measurements follow the trends of the microscopic ones having slight deviations due to the technical characteristics of the endoscopic probes.
Work and results include:

1) The development of a prototype instrument that incorporates contrast enhancing method for reflectance spectroscopy into a flexible endoscopic setup
2) Test ELASCA during uterus transplant surgery
3) Improvement of the set-up in terms of equipment synchronisation and speed of image acquisition Also post-acquisition image processing algorithms were improved
4) Performing controlled in vitro to test the accuracy of flow measurements with the flexible endoscope.
5) Comparative experiments of ELASCA with similar microscopic set up in terms of evaluation of flow speed at capillaries

Further development of this instrumentation could lead to a product with the capability to provide information on tissue morphology, biochemistry and oxygenation with high clinical utility. This improved technological instrument could be translated to the clinic using dedicated research activities for implemented into Minimally Invasive Surgery (MIS) for intraoperative imaging, for screening precancerous dysplasia, for detecting and mapping suspicious sites in the peritoneum, the liver and kidney, for visualizing of the bile duct and observing the oxygenation status of organs and evaluating transplant organ viability

This device has potentially clinical utility and could improve diagnostics of cardiovascular diseases, cancer, ischemia, effective monitoring of microcirculation at organs and could be used to assess the perfusion and viability of transplant organs. The developed flexible endoscope could facilitate the translation of these imaging modalities into the clinical environment. It has the potential to be applied to (MIS) procedures, using the multidisciplinary expertise and the technologies that currently exist and further being developed at the Hamlyn Centre for Robotic Surgery

Multidisciplinary research developing methods for diagnosis and screening is a rapidly emerging field in the international and the European research community. EU and national research agencies have a strong interest to support further research in this area in order to enhance its visibility, keep European researchers within Europe and increase its competitiveness globally. This project’s results has an impact on enhancing the competitiveness of the European Research Area in the emerging field of biomedical imaging as well as economic issues related with effective diagnosis and treatment at relatively low cost, which is highly desirable for the healthcare systems.