Abstract
Purpose :
To develop an advanced imaging system for longitudinal visualization of the progression of choroidal neovascularization (CNV) in an age-related macular degeneration animal model using multimodal photoacoustic microscopy (PAM), optical coherence tomography (OCT), and fluorescence imaging (FI)
Methods :
Six New Zealand rabbits were used to create CNV using subretinal injection of Matrigel and vascular endothelial growth factor (VEGF). For CNV targeting, rabbits received an intravenous injection of 400 µL ultraminiature gold nanochains (GNC) conjugated with RGD peptide at a concentration of 2.5 mg/mL. The margin and location of CNV were detected by PAM, OCT, and FI imaging. PAM images were captured using the excitation wavelength of 578 nm to visualize retinal blood vessels and 650 nm to visualize CNV. All the animal experiments were implemented under a protocol approved by the UM IACUC
Results :
The GNC demonstrated great biocompatibility with high targeting efficiency in in vitro studies. We also found that GNC can be excreted via urine after intravenous injection (IV) into rabbits. All the rabbits have CNV observed by late phase leakage on fluorescein angiography. After IV administration of GNC, the margin of CNV were clearly differentiated from the surrounding retinal vessels with strong PA signal and high resolution (Figure 1). Overlay three-dimensional PAM images obtained at 578 and 650 nm demonstrate the entire structure of CNV. OCT images offer additional details about the structure of the retina and the location of CNV
Conclusions :
In this study, a new multimodal platform technology is introduced for photoacoustic microscopy (PAM), optical coherence tomography (OCT), and fluorescence molecular imaging. The study demonstrates the capability to monitor the degree and margin of choroidal neovascularization (CNV) for a period of up to 28 days, accurately distinguishing it from the surrounding vasculature. This highlights the potential utility of contrast-enhanced multimodal molecular imaging as a valuable tool for investigating ocular diseases
This abstract was presented at the 2024 ARVO Imaging in the Eye Conference, held in Seattle, WA, May 4, 2024.