Spectral Analysis Comparison of Pushbroom and Snapshot Hyperspectral Cameras for In-Vivo Brain Tissues and Chromophores Identification

SignificanceHyperspectral imaging sensors have rapidly advanced, aiding in tumor diagnostics for in-vivo brain tumors. Linescan cameras effectively distinguish between pathological and healthy tissue, while snapshot cameras offer a potential alternative to reduce acquisition time. AimOur research compares linescan and snapshot hyperspectral cameras for in-vivo brain tissues and chromophores identification. ApproachWe compared a lines-can pushbroom camera and a snapshot camera using images from 10 patients with various pathologies. Objective comparisons were made using unnormalized and normalized data for healthy and pathological tissues. We utilized Interquartile Range (IQR) for the Spectral Angle Mapping (SAM), the Goodness-of-Fit Coefficient (GFC), and the Root Mean Square Error (RMSE) within the 659.95 to 951.42 nm range. Additionally, we assessed the ability of both cameras to capture tissue chromophores by analyzing absorbance from reflectance information. ResultsThe SAM metric indicates reduced dispersion and high similarity between cameras for pathological samples, with a 9.68% IQR for normalized data compared to 2.38% for unnormalized data. This pattern is consistent across GFC and RMSE metrics, regardless of tissue type. Moreover, both cameras could identify absorption peaks of certain chromophores. For instance, using the absorbance measurements of the linescan camera we obtained SAM values below 0.235 for four peaks, regardless of the tissue and type of data under inspection. These peaks are: one for cytochrome b in its oxidised form at{lambda} = 422 nm, two for HbO2 at{lambda} = 542 nm and{lambda} = 576 nm, and one for water at{lambda} = 976 nm. ConclusionThe spectral signatures of the cameras show more similarity with unnormalized data, likely due to snapshot sensor noise, resulting in noisier signatures post-normalization. Comparisons in this study suggest that snapshot cameras might be viable alternatives to linescan cameras for real-time brain tissues identification.