Histopathologic Features of Diabetic Microangiopathy Imaged Using an Adaptive Optics Scanning Laser Fluorescein Angiography

Abstract

 

Purpose

 

To describe the fluorescein angiographic features of diabetic microangiopathy lesions imaged with an adaptive optics scanning light ophthalmoscope (AOSLO) compared to their appearance on conventional fundus photography and spectral domain optical coherence tomography (SDOCT).

 

Methods

 

AOSLO images (790nm; 1° degree field of view) without fluorescein dye were collected in 15 adult diabetic retinopathy patients to identify microvascular points of interest. Patients then ingested 1gm fluorescein dye mixed in 4oz of orange juice. Simultaneous reflectance (790 nm) and fluorescence (488 nm excitation, 503-548 nm emission) AOSLO images (1° field of view) were collected between 15 and 60 minutes post-ingestion. For comparison with conventional imaging techniques, fundus imaging with and without intravenous fluorescein were performed.

 

Results

 

In the fluorescence AOSLO channel we were able to visualize microangiopathic features of diabetic microangiopathy in vivo at the level of the retinal capillary bed. A number of lesions were clearly delineated, including a variety of microaneurysms, capillary loops, IRMA, and neovascularization, which could not be seen well in the 790nm channel. These lesions typically appeared as red dots on fundus photography or bright spots on clinical fluorescein angiography. OCT appearances were typically less distinct.

 

Conclusions

 

Micro fluorescein angiography can by successfully and safely achieved using AOSLO in diabetic patients revealing anatomic features previously seen only on pathology slides. This level of clinical imaging may prove useful for evaluating the impact of treatment at a the microscopic scale.

 

 

Figure 1. A:Segment of wide field fundus photograph demonstrating microaneurysms, tortuosity, and neovascularization. B:Standard wide field fluorescein angiogram with color coded frames corresponding to micro angiographic images in figure 2. C:Corresponding SD-OCT slice through the red frame revealing microaneurysms

 

 

Figure 2. AOSLO FA images corresponding to frames in figure 1 revealing details of microangiopathy including vascular loops (A,B,C) microaneurysms(A,B,C), and capillary dropout( A, B,C).

 

Keywords: 550 imaging/image analysis: clinical • 499 diabetic retinopathy • 688 retina