Intraoperative fluorescence perfusion assessment should be corrected by a measured subject-specific arterial input...

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Pharmacokinetics

Background:

• Intraoperative fluorescence imaging uses indocyanine green (ICG) for perfusion assessment.
• The arterial input function (AIF) describes dye concentration over time in arteries.
• AIF shape and magnitude are influenced by injection parameters and dye dispersion.

Purpose of the Study:

• To investigate how variations in ICG injection affect the AIF.
• To quantify the impact of AIF changes on fluorescence perfusion metrics.
• To evaluate the benefit of correcting fluorescence imaging data with subject-specific AIFs.

Main Methods:

• Numerical simulations of AIFs and tissue concentration curves.
• Convolution of simulated AIFs with a tissue homogeneity model.
• Modeling of six tissue types: normal/glioma brain, normal/ischemic skin, normal/osteonecrotic bone.

Main Results:

• AIF perturbations caused up to 80% error in total intensity and 200% error in time-to-peak (TTP).
• Errors were most pronounced in brain tissue, followed by skin, then bone.
• Ingress slope error reached 60% across all tissue types, impacting key imaging parameters.

Conclusions:

• AIF variations significantly alter fluorescence perfusion assessment metrics.
• Correcting with a measured, subject-specific AIF is crucial for accurate interpretation.
• Pulse dye densitometry is recommended for measuring patient-specific AIFs in intraoperative settings.