Quantification of bowel ischaemia using real‑time multispectral Single Snapshot Imaging of Optical Properties (SSOP)

Background. Single snapshot imaging of optical properties (SSOP) is a relatively new non-invasive, real-time, contrast-freeoptical imaging technology, which allows for the real-time quantitative assessment of physiological properties, includingtissue oxygenation (StO2). This study evaluates the accuracy of multispectral SSOP in quantifying bowel ischaemia in apreclinical experimental model. Methods. In six pigs, an ischaemic bowel segment was created by dividing the arcade branches. Five regions of interest(ROIs) were identified on the bowel loop, as follows: ROI 1: central ischaemic; ROI 2: left marginal; ROI 3: left vascularised;ROI 4: right marginal; and ROI 5: right vascularised. The Trident imaging system, specifically developed for real-time tissueoxygenation imaging using SSOP, was used to image before (T0) and after ischaemia induction. Capillary and systemiclactates were measured at each time point (T0, T15, T30, T45, T60), as well as StO2 values acquired by means of SSOP(SSOP-StO2). Results.The mean value of SSOP-StO2 in ROI 1 was 30.08 and was significantly lower when compared to marginalROIs (ROI 2 + ROI 4: 45.67p = < 0.0001), and to vascularised ROIs (ROI 3 + ROI 5: 48.08 p = < 0.0001).SSOP-StO2 was significantly correlated with normalised lactates r = − 0.5892 p < 0.0001 and with histology r =− 0.6251p = 0.0002. Conclusion Multispectral SSOP allows for a contrast-free accurate assessment of small bowel perfusion identifying physiologicaltissue oxygenation as confirmed with perfusion biomarkers.