Integrated laser speckle contrast and multispectral imaging for in vivo multimodal assessment of small intestinal viability

Abstract

Accurate intraoperative identification of necrotic intestinal segments remains challenging owing to the limitations of invasive methods or single-parameter techniques. A multimodal system integrating laser speckle contrast and multispectral imaging was developed. The noninvasive system simultaneously acquires images of blood flow index (BFI) and tissue oxygen saturation (StO₂), which enables the assessment of tissue metabolic rate of oxygen (tMRO₂). For in vivo calculation of StO₂ in the small intestine, a linear transformation algorithm based on three hemoglobin isosbestic points was employed, and an optimal characteristic wavelength (763 nm) was selected to reduce background interference. The system was validated in the small intestinal ischemia and reperfusion model of rabbits. During occlusion, BFI and tMRO₂ rapidly declined by approximately 80 %, while StO₂ gradually decreased, ultimately by approximately 46 %. Upon reperfusion, segments with reversible damage exhibited a significant recovery. In contrast, irreversibly necrotic regions showed only transient increases before secondary decline. Although either modality alone can identify necrotic intestinal segments that are indiscernible to the human eye, the location of occluded mesenteric vessels cannot be accurately identified. The multimodal imaging approach resolved this limitation, and enabled reliable identification of potentially and irreversibly necrotic segments, as confirmed by pathological analysis. This system provides a noninvasive and cost-effective solution for intraoperative intestinal viability assessment and surgical precision.