Optical effects on the surrounding structure during quantitative analysis using indocyanine green videoangiography: A...

Area of Science:

• Medical Imaging
• Optical Physics
• Surgical Technology

Background:

• Quantitative evaluations of intraoperative fluorescent intensity using indocyanine green (ICG) with videoangiography (VAG) are frequently reported.
• The influence of scattering and point-spread functions (PSF) on these quantitative ICG-VAG assessments remains unexplored.
• ICG administered peripherally reaches tissues intra-arterially, necessitating reliable quantitative methods.

Purpose of the Study:

• To investigate the impact of high-intensity structures on adjacent areas for more dependable intraoperative quantitative ICG-VAG evaluations.
• To analyze the optical effects influencing fluorescent intensity measurements in surgical settings.

Main Methods:

• Utilized a phantom model and a surgical fluorescent microscope for the study.
• Defined regions of interest (ROIs) around a vessel model and in adjacent areas up to 3 cm away.
• Quantified fluorescent intensity within ROIs of varying distances from the high-intensity source.

Main Results:

• A 10% intensity was detected in an ROI (6.8 mm) near the vessel phantom, despite no direct fluorescent structure.
• Fluorescent intensity decreased progressively as the ROI distance from the vessel model increased.
• Linear regression analysis yielded the formula: Y(real/A) = 29 Exp(-0.062X) + 164.3 Exp(-1.81X), relating intensity (Y) to distance (X).

Conclusions:

• The proximity of high-intensity structures and the size of the region of interest (ROI) can significantly influence quantitative ICG-VAG intensity evaluations.
• Optical effects, including scattering and PSF, must be considered during intraoperative intensity studies using surgical microscopes for accurate interpretation.