Fibre optic probes for hysteroscopic measurement of uterine hypoxia

Recent findings in animal models and human tissue suggest that deficient menstrual endometrial hypoxia results in heavy menstrual bleeding (HMB). There is no current method available to directly measure endometrial oxygen concentrations during hysteroscopy investigation of the underlying cause of HMB. We propose that an optical fibre-based probe delivered through the working channel of a hysteroscope can accurately assess uterine oxygenation. This probe will be designed to transmit and collect broadband white / NIR (~550 nm - 1050 nm) light using multiple fibre optics co-packaged and modified for side emission / collection of light passing through different depths of tissue. Observed spectral variations reveal haemoglobin oxygen saturation, while the controlled depth measurement allows comparison of the endometrium layer to the deeper myometrium muscular outer layer to observe the expected (or defective) relative hypoxia in the menstrual endometrium. An initial co-packaged fibre probe has been prototyped, optimising diffuse emission and collection of light into surrounding tissue. An initial investigation shows real time spectral changes, observing the variation in haemoglobin oxygenation due to pulse and breathing. Fibre probes were placed onto tissue and the separation of the fibre probes was varied, allowing the spectral properties of different tissue types at varying depths to be observed. Introducing more fibres into the probe offers better resolving of obscured tissue layers, a customised multi-fibre spectroscopy measurement instrument is in development to enable this. Thus, our probe could provide a clinical diagnostic tool to quantify tissue hypoxia in the endometrium and facilitate personalised diagnosis and management of the common, debilitating symptom of HMB.