Despite collateralization from native gastric vasculature, the stomach may be at risk for regional ischemia during revisional surgery. Laser Speckle Contrast Imaging (LSCI) provides dye-less, real-time tissue perfusion visualization with high spatial resolution, which ICG lacks. We determined relative, regional gastric perfusion using LSCI compared to Laser Doppler Imaging (LDI) in a porcine gastric tube.
ActivSightTM (Activ Surgical) is an FDA-cleared laparoscopic device combining LSCI/ICG fluorescence imaging. LSCI detects tissue blood flow by capturing coherent laser light scatter from red blood cells, with a prototype feature to quantify perfusion in relative perfusion units (RPU). A porcine gastric tube entirely reliant on the right gastroepiploic artery was created (Figure 1), and tissue perfusion measured using LSCI (ActivSightTM) and LDI (Moor Technologies).
With a single arterial supply, porcine gastric tube demonstrates linearly declining perfusion gradients with increasing distance from vascular source - gastric tip perfusion measures 71%/100% lower than base as quantified by LSCI/LDI (Figure 2A). LSCI detects perfusion more precisely as function of distance from vascular source than LDI (Pearson's .952/.682). For any given distance from vascular source, LSCI detects significant perfusion differences along mesoaxial planes with middle of tube demonstrating highest RPU followed by inner/outer curves (RPU .62/.44/.31, p=.00001) (Figure 2B). LDI did not detect significant perfusion differences between these planes (p=.684).
Gastric perfusion appears to be linearly dependent on distance from a supplying artery, suggesting regional perfusion differences. LSCI detects dye-less, real-time, spatially specific perfusion, which may provide a useful tool in revisional gastric surgery.