Abstract
Purpose:
1. To demonstrate the utility of ultra-widefield fluorescein angiography (UWFFA) as an objective measure of inflammatory activity in patients with uveitis. 2. To develop a method to quantify retinal vascular leakage on UWFFA in uveitis patients. 3. To correlate retinal vascular leakage analysis with inflammatory status in uveitis patients based on clinical exam.
Methods:
Uveitis patients were evaluated with UWFFA Optos® 200Tx between May 2012 and December 2013. Uveitis status was deemed as having active or inactive inflammation based on clinical examination. Images were initially graded to identify those with or without leakage. One late phase UWFFA image from each eye was transformed into a standardized projection to accurately represent the 3-dimensional globe in a 2-dimensional image. A custom designed image analysis software was developed to automatically and objectively quantify retinal vascular leakage by eliminating the retinal vessels and optic nerve, and quantified only hyperfluorescent perivascular leakage (white areas within the image); the total leakage area was then divided by the total area of the retinal surface in the standardized image.
Results:
An initial set of 254 uveitis patients and a total of 1053 eye images were reviewed. Corresponding eye exams were reviewed for each imaging session and revealed 607 eye images deemed clinically active. Of the 1053 eye images, 628 eye images exhibited vascular leakage. All 607 eye images (100%) which were clinically active were also found to have leakage. Automated leakage analysis was then performed on a subset of 164 images (93 eyes with active inflammation, 71 with inactive inflammation). Mean leakage area percentage in eyes with active inflammation was 4.4% of the total area of the retina, whereas mean leakage area of eyes with inactive inflammation was 0.9% (p < 0.0001).
Conclusions:
Retinal vascular leakage on UWFFA accurately identifies and correlates with active inflammation in patients with uveitis. Automated retinal vascular leakage analysis highly correlates with inflammatory status based on clinical examination. Based on automated retinal vascular leakage, an objective measure of inflammation may not only guide therapeutic decisions, but may also help identify subclinical inflammation and may be used as an objective endpoint of future clinical treatment trials in uveitis.