Comparative Study Between a Customized Bimodal Endoscope and a Benchtop Microscope for Quantitative Tissue Diagnosis.

Area of Science:

• Biomedical Engineering
• Neuroscience
• Surgical Oncology

Background:

• Surgical removal is the standard for brain tumors, but differentiating tumor margins from healthy tissue is challenging.
• Infiltrating tumor residuals increase recurrence risk and decrease patient survival.
• Accurate intraoperative delimitation of tumor boundaries is crucial for improving surgical outcomes.

Purpose of the Study:

• To develop and validate a two-photon fluorescence fibered endomicroscope for real-time, intraoperative brain tumor diagnosis.
• To assess the endomicroscope's ability to provide reliable diagnostic information for distinguishing healthy from cancerous brain tissue.
• To confirm that the developed endoscope can replicate diagnostic indicators from an established optical database.

Main Methods:

• Development of a two-photon fluorescence fibered endomicroscope for intraoperative use.
• Construction of an optical database characterizing healthy and tumor brain tissues using endogenous fluorescence.
• Comparison of spectrally and time-resolved fluorescence signals from the endoscope with a standard multiphoton microscope using 46 fresh brain tissue samples.

Main Results:

• The endoscope demonstrated higher excitation efficiency and endogenous fluorescence signal collection ability compared to the reference setup.
• Similar molecular ratios and fluorescence lifetime distributions were obtained from both the endoscope and the reference microscope.
• The spectral discrimination ability of the bimodal endoscope was validated, confirming its reliability for tissue differentiation.

Conclusions:

• The developed bimodal fibered endoscope efficiently excites and collects signals, providing high-quality, exploitable data for intraoperative discrimination of human brain tissues.
• This technology offers a promising tool for neurosurgeons to improve tumor boundary delineation and surgical precision.
• The validated performance represents a significant preliminary step towards multimodal imaging for enhanced brain tumor surgery.