Prototype Ultra-High Speed Swept Source Optical Coherence Tomography Angiography compared with Intravenous Fluorescein Angiography in Diabetic Retinopathy

Abstract

 

Purpose

 

To compare the utility of a prototype ultrahigh speed swept source optical coherence tomography (OCT) angiography with intravenous fluorescein angiography (IVFA) in patients with diabetic retinopathy (DR).

 

Methods

 

This is a prospective observational cross-sectional study. A prototype ultra high speed swept source OCT angiography was performed using 400,000 A scans per second to scan 3mm × 3mm and 6mm × 6mm areas centered at the fovea in 11 normal eyes and 29 eyes in patients with diabetes. IVFA was performed in all patients within 8 weeks of the OCT angiography. Inclusion criteria for diabetic patients included type 1 or type 2 diabetes with a clinical examination by a retinal specialist confirming the presence of DR. Two masked Boston Image Reading Center (BIRC) trained readers reviewed both IVFA and OCT angiography images independently on all patients with diabetes to identify microaneurysms and other retinal abnormalities on both images. The size of the foveal avascular zone (FAZ) and the perifoveal intercapillary area was measured in both control and diabetic patients using the BIRC image analysis software. The findings were then compared to determine the clinical utility of OCT angiography compared with IVFA.

 

Results

 

The FAZ and perifoveal intercapillary area were enlarged in patients with DR compared with controls. Ultra high speed swept source OCT angiography was able to obtain detailed maps of the retinal microvasculature and was able to identify the majority of microaneurysms noted on fluorescein angiography with localization of their exact retinal depth within a specific vascular plexus using en face imaging. OCT angiography also revealed retinal vascular abnormalities and microaneurysms not detected by IVFA.

 

Conclusions

 

Ultra high speed swept source OCT angiography appears to be of significant utility in patients with DR, and is completely non-invasive as compared with IVFA. It is able to detect the majority of microaneursyms seen by IVFA, and is also able to delineate other areas of retinal vascular abnormalities that were not seen clinically or on IVFA. OCT angiography is also more accurate for determining the FAZ and perifoveal intercapillary area. OCT angiography may be of clinical utility in the evaluation and treatment of diabetic patients.  

 

OCT angiography (left) versus IVFA (right) of the same eye with NPDR.