Multispectral imaging of organ viability during uterine transplantation surgery

Abstract

Uterine transplantation surgery has been proposed as a treatment for permanent absolute uterine factor infertility (AUFI) in the case of loss of the uterus. Due to the complexity of the vasculature correct reanastomosis of the blood supply during transplantation surgery is a crucial step to ensure reperfusion and viability of the organ.While techniques such as fluorescent dye imaging have been proposed to visualise perfusion there is no gold standard for intraoperative visualisation of tissue oxygenation. In this paper results from a liquid crystal tuneable filter (LCTF)-based multispectral imaging (MSI) laparoscope are described. The system was used to monitor uterine oxygen saturation (SaO 2 ) before and after transplantation. Results from surgeries on two animal models (rabbits and sheep) are presented.A feature-based registration algorithm was used to correct for misalignment induced by breathing or peristalsis in the tissues of interest prior to analysis. An absorption spectrum was calculated at each spatial pixel location using reflectance data from a reference standard, and the relative contributions from oxy-and deoxyhaemoglobin were calculated using a least squares regression algorithm with non-negativity constraints.Results acquired during animal surgeries show that cornual oxygenation changes are consistent with those observed in point measurements taken using a pulse oximeter, showing reduced SaO 2 following reanastomosis. Values obtained using the MSI laparoscope were lower than those taken with the pulse oximeter, which may be due to the latter's use of the pulsatile arterial blood signal. Future work incorporating immunological test results will help to correlate SaO 2 levels with surgical outcomes.

Uterine transplantation: past, present and future

“…A microvascular technique was initially employed using a uterine vessel anastomosis but thrombotic complications necessitated the development of a macrovascular method, in the form of a large vessel patch. Other important considerations include the use of cervical biopsies to detect rejection and the application of multi‐spectral imaging to detect blood flow within the uterus . Following pregnancies after UTx, in rabbit, mouse, primates and sheep models, the next logical step was for further attempts in humans.…”

“…Other important considerations include the use of cervical biopsies to detect rejection 5 and the application of multi-spectral imaging to detect blood flow within the uterus. 6 Following pregnancies after UTx, in rabbit, 7 mouse, 8 primates 9 and sheep 10 models, the next logical step was for further attempts in humans.…”

Intraoperative measurement of bowel oxygen saturation using a multispectral imaging laparoscope

“…The MSI laparoscope hardware, which uses a similar construction to that shown by Zuzak [21], has been introduced previously [22,23] and is shown in Fig. 1.…”

Inference of Tissue Haemoglobin Concentration from Stereo RGB

“…Laparoscopic images contain only macroscopic structural and radiometric information, that does not directly highlight tissue function or characteristics which may be used to identify malignancy. Pathological signals such as oxy and de-oxy haemoglobin (HbO 2 , Hb) concentration, often correspond to tissue structure [18] or viability [6] and are detectable by their characteristic attenuation of light in the visible wavelength range. Detecting and displaying this information in vivo could provide a powerful tool to the surgeon, but current imaging solutions often demand modification the laparoscopic imaging hardware or protocols.…”