In vivo ultrasound-switchable fluorescence imaging

TL;DR

This paper demonstrates the first successful in vivo ultrasound-switchable fluorescence imaging in mice, using a stable near-infrared contrast agent to achieve high-resolution imaging of various tissues, validated by micro-CT.

Contribution

It introduces a novel in vivo USF imaging technique with a new stable contrast agent, enabling high-resolution deep tissue imaging in live animals.

Findings

Successful in vivo USF imaging in mice and pigs

The contrast agent is stable and accumulates mainly in the spleen

USF imaging results are validated by micro-CT

Abstract

Ultrasound-switchable fluorescence (USF) imaging was recently developed to overcome the limitation of the poor spatial resolution of the conventional fluorescence imaging in centimeter-deep tissue. However, in vivo USF imaging has not been achieved so far because of the lack of stable near-infrared contrast agents in a biological environment and the lack of data about their biodistributions. In this study, for the first time, we achieved in vivo USF imaging successfully in mice with high resolution. USF imaging in porcine heart tissue and mouse breast tumor via local injections were studied and demonstrated. In vivo and ex vivo USF imaging of the mouse spleen via intravenous injections was also successfully achieved. The results showed that the USF contrast agent adopted in this study was very stable in a biological environment, and it was mainly accumulated into the spleen of the mice. All the results of USF imaging were validated by a commercial micro-CT.