A hyperspectral imaging dataset and Grassmann manifold method for intraoperative pixel-wise classification of metastatic colon cancer in the liver

Hyperspectral imaging (HSI) holds significant potential for transforming the field of computational pathology. However, the number of HSI-based research studies remains limited, and in many cases, the advantages of HSI over traditional RGB imaging have not been conclusively demonstrated, particularly for specimens collected intraoperatively. To address these challenges we present: (i) a database consisted of 27 HSIs of hematoxylin-eosin stained frozen sections, collected from 14 patients with colon adenocarcinoma metastasized to the liver. It is aimed to validate pixel-wise classification for intraoperative tumor resection; (ii) a novel method which combines Grassmann points with nearest subspace classifier for pixel-wise classification of HSIs. The HSIs were acquired in the spectral range of 450 nm-800 nm, with a resolution of 1 nm, resulting in images of 1384 × 1035 pixels. Pixel-wise annotations were performed by two pathologists and one medical expert. To overcome challenges such as experimental variability and the lack of annotated data, we applied Grassmann manifold (GM) approach in combination with spectral-spatial features extracted by tensor singular spectrum analysis (TSSA) method to non-overlapping patches of 230 × 258 pixels. Using only 1 % of labeled pixels per class, the GM-TSSA method achieved a micro balanced accuracy (BACC) of 0.963 and a micro F₁-score of 0.959 on the HSI dataset. The GM-TSSA approach outperformed six deep learning architectures trained with 63 % of labeled pixels. Data are available at: https://data.fulir.irb.hr/islandora/object/irb:538, and code is available at: https://github.com/ikopriva/ColonCancerHSI.