Biomarkers of diabetic retinopathy based on dynamic fluorescein angiography in control and diabetic patients

Abstract

Purpose : The purpose was to demonstrate that the retinal vascular permeability and volumetric blood flow mapping from dynamic fluorescein angiography and kinetic tracer modeling can detect vascular changes in diabetic patients.

Methods : A routine fluorescein angiogram (FA) was performed in two normal control subjects and three diabetic patients. A small bolus of fluorescein dye (0.5 ml of 10%) was injected to obtain videoangiograms (30°, 90 sec movie) using Heidelberg Spectralis. The images were obtained immediately after the injection to capture the initial filling of the blood vessels. The fluorescein images were loaded into MATLAB. Eye movement was corrected via a motion correction algorithm. Either plug-flow or AATH tracer kinetic model was applied to obtain retinal vascular permeability and blood flow maps from the control and diabetic patients.

Results : Control subjects had no ocular abnormality. Based on the kinetic model analysis, the control subjects had average volumetric blood flow of 11.87 ± 3.51 ml/min/100g. The average vascular permeability (extraction fraction) for the control subjects was 0.0036 ± 0.0011. The diabetic patients had no DR to mild non-proliferative DR. The patients also had signs of diabetic macular edema. For the diabetic patients, the average volumetric blood flow was 8.47 ± 1.15 ml/min/100g. The average vascular permeability from the diabetic patients increased to 0.082 ±. 0.057. There were significant differences in vascular permeability.

Conclusions : The current data demonstrated that dynamic fluorescein enhanced fluorescent imaging and tracer kinetic model can detect changes of volumetric blood flow and vascular permeability in diabetic patients. Specifically, an increase in the vascular permeability, in absence of proliferation, may be a sensitive parameter to detect vascular abnormality. This study demonstrated that the vascular permeability and blood flow may be powerful biomarkers for early detection of DR.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.