Abstract
Purpose :
To demonstrate the value of the laser-scanning optical-resolution photoacoustic microscopy (LSOR-PAM) system and the conventional multimodal imaging techniques in the evaluation of laser-induced retinal injury and choroidal neovascularization (CNV) in rats.
Methods :
Different degrees of retinal injury were induced using laser photocoagulation. We compared the LSOR-PAM system with conventional imaging techniques in evaluating retinal injury with or without CNV. Six additional rats, treated with an anti-VEGF agent or immunoglobulin G, were imaged at days 7 and 14 post-laser photocoagulation, then compared with respect to the CNV lesion areas.
Results :
In the retinal injury model, the fundus autofluorescence image showed simple hyperreflection, while the lesion displayed abundant high- and low-amplitude photoacoustic signals, demonstrating different degrees of retinal pigment epithelium(RPE) injury. In the PAM B-scan image, the RPE signal was extracted. which was unattainable by optical coherence tomography (OCT). Additionally, the CNV lesion was presented in the “high-low-high” signal intensity distribution, of which the high signal corresponded to the hyperfluorescence in the fundus fluorescein angiography (FFA). Dark “antenna” signals shown in PAM, were comparable to that in ex vivo immunofluorescence imaging, which was invisible in FFA. The effect of anti-VEGF agents can be visualized by PAM, the same as conventional FFA and OCT.
Conclusions :
LSOR-PAM system can effectively and non-invasively detect laser-induced retinal injury and CNV in rats. It has potential value to be a reliable tool for fundamental investigation and clinical use in retinal diseases.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.