Multispectral optoacoustic tomography of myocardial infarction

Highlights

► Multispectral optoacoustics enables in vivo preclinical imaging of heart infarct. ► The spatial resolution is superior to previous deep-tissue optical techniques. ► Molecular contrast is provided by an exogenous inflammation-targeted agent. ► Endogenous contrast provides an anatomical reference for the molecular signal.

Abstract

Objectives

To investigate the feasibility of a high resolution optical imaging strategy for myocardial infarction.

Background

Near-infrared approaches to imaging cardiovascular disease enable visualization of disease-associated biological processes in vivo. However, even at the scale of small animals, the strong scattering of light prevents high resolution imaging after the first 1–2 mm of tissue, leading to degraded signal localization.

Methods

Multispectral optoacoustic tomography (MSOT) was used to non-invasively image myocardial infarction (MI) in a murine model of coronary artery ligation at resolutions not possible with current deep-tissue optical imaging methods. Post-MI imaging was based on resolving the spectral absorption signature of a dendritic polyglycerol sulfate-based (dPGS) near-infrared imaging agent targeted to P- and L-selectin.

Results

In vivo imaging succeeded in detection of the agent in the injured myocardium after intravenous injection. The high anatomic resolution (<200 μm) achieved by the described method allowed signals originating in the infarcted heart to be distinguished from uptake in adjacent regions. Histological analysis found dPGS signal in infarcted areas, originating from leukocytes and endothelial cells.

Conclusions

MSOT imaging of myocardial infarction provides non-invasive visualization of optical contrast with a high spatial resolution that is not degraded by the scattering of light.