Fluorescence Imaging Reveals Nerves Under Normal Operating-Room Lighting

Fluorescence imaging may improve nerve visualization, but weak signals can be obscured by operating-room lighting. To overcome this limitation, researchers have developed an imaging approach that enables visualization of labeled nerves without dimming or switching off the room lights.

Researchers at Physical Sciences Inc. and Dartmouth College developed a spatio-temporally modulated fluorescence imaging system for intraoperative nerve identification. Designed for fluorescence-guided surgery, the technology uses fluorescent agents to selectively highlight nerve tissue while distinguishing nerve-specific signals from strong background illumination in the operating room.

The system uses line-scan imaging to capture fluorescence from narrow regions sequentially, encoding the signal with a distinct spatial frequency and limiting detection to a brief time window. Image-processing algorithms then isolate signals matching these spatial and temporal patterns while suppressing background light that remains relatively constant over time and uniform across the field of view.

Researchers evaluated the system under lighting conditions representative of a standard operating room. Preliminary studies demonstrated its ability to visualize nerve structures despite strong ambient illumination. Testing progressed from live animal models to excised human nerve specimens and perfused amputated human limbs, providing a more clinically relevant assessment of the technology's potential for intraoperative nerve visualization.

Across the experiments, the system produced high-contrast fluorescence images of nerve tissue under normal operating-room illumination. The findings indicate that spatial and temporal modulation can separate relatively weak nerve fluorescence from a much brighter optical background. The work was published in the Journal of Biomedical Optics.

The approach may help remove a practical barrier to adopting fluorescence-guided nerve imaging in surgical workflows. Further clinical evaluation will be needed to determine how the technique performs during human surgical procedures. By addressing the imaging environment rather than requiring changes to room lighting, the system could make fluorescence-based nerve visualization easier to integrate into surgery.

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Physical Sciences Inc.
Dartmouth College