Frequency-Domain Denoising-Based in Vivo Fluorescence Imaging

TL;DR

This paper introduces a frequency-domain denoising method for in vivo NIR-II fluorescence imaging, significantly enhancing image quality, penetration depth, and enabling real-time surgical navigation with FDA-approved agents.

Contribution

The work presents a novel FDD-based imaging technique that greatly improves SBR and SNR, enabling clinical translation and real-time visualization in NIR-II fluorescence imaging.

Findings

SBR and SNR improved by over 2,500-fold and 300-fold respectively

Penetration depth doubled, with 95% reduction in contrast agent dosage

Real-time 600 Hz video visualizes contrast diffusion and vessel differentiation

Abstract

The second near-infrared window (NIR-II, 900-1,880 nm) has been pivotal in advancing in vivo fluorescence imaging due to its superior penetration depth and contrast. Yet, its clinical utility remains limited by insufficient imaging temporal-spatial resolution and the absence of U.S. Food and Drug Administration (FDA)-approved NIR-II contrast agents. This work presents a frequency-domain denoising (FDD)-based in vivo fluorescence imaging technique, which can improve signal-to-background ratio (SBR) and signal-to-noise ratio (SNR) by more than 2,500-fold and 300-fold, respectively. The great enhancement yields a doubled penetration depth and a 95% reduction in contrast agent dosage or excitation light intensity for mouse vascular imaging. Additionally, we achieved a SBR far exceeded the Rose criterion in the observation of tumor margins and vessels in mice using Indocyanine Green (ICG), demonstrating the feasibility of NIR-II surgical navigation with FDA-approved agents. Furthermore, a 600 Hz real-time video enables visualization of the entire contrast agent diffusion process within the mouse body and differentiation between arteries and veins. This innovative technique, characterized by exceptional sensitivity, efficiency, and robustness, presents a promising solution for clinical applications, particularly in NIR-II surgical navigation.