Evaluating the identification of the extent of gastric cancer by over-1000 nm near-infrared hyperspectral imaging using surgical specimens

Significance: Determining the extent of gastric cancer (GC) is necessary for evaluating the gastrectomy margin for GC. Additionally, determining the extent of the GCthat is not exposed to the mucosal surface remains difficult. However, near-infrared(NIR) can penetrate mucosal tissues highly efficiently.Aim: We investigated the ability of near-infrared hyperspectral imaging (NIR-HSI) toidentify GC areas, including exposed and unexposed using surgical specimens, andexplored the identifiable characteristics of the GC.Approach: Our study examined 10 patients with diagnosed GC who underwentsurgery between 2020 and 2021. Specimen images were captured using NIRHSI. For the specimens, the exposed area was defined as an area wherein thecancer was exposed on the surface, the unexposed area as an area wherein thecancer was present although the surface was covered by normal tissue, and thenormal area as an area wherein the cancer was absent. We estimated the GC(including the exposed and unexposed areas) and normal areas using a supportvector machine, which is a machine-learning method for classification. The prediction accuracy of the GC region in every area and normal region was evaluated.Additionally, the tumor thicknesses of the GC were pathologically measured, andtheir differences in identifiable and unidentifiable areas were compared usingNIR-HSI.Results: The average prediction accuracy of the GC regions combined with bothareas was 77.2%; with exposed and unexposed areas was 79.7% and 68.5%,respectively; and with normal regions was 79.7%. Additionally, the areas identifiedas cancerous had a tumor thickness of <2 mm.Conclusions: NIR-HSI identified the GC regions with high rates. As a feature, theexposed and unexposed areas with tumor thicknesses of <2 mm were identifiedusing NIR-HSI.