Two-photon microendoscope for label-free imaging in stereotactic neurosurgery

Area of Science:

• Biomedical Engineering
• Neuroscience
• Optical Imaging

Background:

• Minimally invasive surgical procedures require advanced imaging tools.
• Current microendoscopes have limitations in resolution and field of view for delicate brain tissue.
• Gradient refractive index (GRIN) optics offer potential for miniaturized, high-performance endoscopes.

Purpose of the Study:

• To develop and characterize a GRIN microendoscope for stereotactic surgery.
• To evaluate its performance in imaging label-free human brain tissue.
• To assess the potential of image classification for identifying specific brain structures.

Main Methods:

• Fabrication of a GRIN microendoscope (1.2 mm diameter, 186 mm length).
• Two-photon imaging at 900 nm excitation, achieving 0.86 µm lateral and 9.6 µm axial resolution.
• Imaging of human brain tissue, capturing autofluorescence and second harmonic generation (SHG).

Main Results:

• The microendoscope successfully imaged label-free human brain tissue.
• Achieved a field of view of approximately 180 µm.
• Image classification models could differentiate between subthalamic nucleus and surrounding tissue based on autofluorescence.

Conclusions:

• The GRIN microendoscope is a viable tool for minimally invasive neurosurgery.
• Label-free imaging with SHG and autofluorescence provides structural information.
• Automated image analysis shows promise for real-time surgical guidance.