Spectral and lifetime measurements of the endogenous fluorescence variation of freshly resected human samples over time: Measuring endogenous fluorescence changes at different moment after tumor or epileptic cortex excision

Analysis of human tissue endogenous fluorescence is becoming a new modality of medical imaging. Its capacities represent the missing link between macroscopic radiological tools such as MRI and CT-scan and the surgeon view during surgical procedures. However, numerous aspects of this signal are not well known. Time dependence is one of these aspects. The aim of this work is to investigate the autofluorescence changes with time. Five ex vivo human samples were studied. Spectral and lifetime measurements were acquired each hour. Fluorescence intensity decreased slightly with time. This decrease existed for healthy and tumoral samples and did not affect the differences between them: higher fluorescence intensity for control samples compared to tumor samples. Lifetime values showed a slight decrease too for both type of tissue. This work is the first report of fresh human brain samples multimodal autofluorescence analysis with time.