Abstract
Purpose :
To demonstrate the role of spectral-domain optical coherence tomography angiography(SD-OCTA) as a clinically relevant tool for objectively monitoring treatment response in proliferative diabetic retinopathy(PDR).
Methods :
This retrospective cohort study reviewed 5 patients with PDR and newly developed neovascularization(NV) between 7/1/2015 and 12/1/2015. Patients were imaged with SD-OCTA AngioPlexTM (ZEISS, Dublin, CA) at baseline centered on the NV with either a 3x3-mm or 6x6-mm scan. Patients then received either intravitreal bevacizumab(IVB), panretinal photocoagulation(PRP) or a combination of both based on clinical need. Patients were re-imaged with SD-OCTA at least once between 1 week and 3 months post-treatment, using the same scan pattern and scan location as baseline. En-face SD-OCTA images were exported and analyzed with ImageJ, a public-domain image processing software developed by the National Institutes of Health available at http://rsb.info.nih.gov/ij to determine lesion area, size and density. NV lesions were manually traced to determine lesion area and greatest linear diameter(GLD); the smallest box that encompassed the NV was drawn around the baseline lesion and the mean gray value of the area was also calculated at baseline and subsequent follow-up. Each measurement was made 3 times to determine intra-grader repeatability standard deviation, and the mean of the 3 measurements was used for final analysis.
Results :
Five patients (3 male), with a mean age of 43 (range 23-64), had a mean follow-up time of 5 weeks (range 1-12 weeks). Two patients were treated with IVB, 2 with PRP and 1 with a combination of both. At visit 2, NV area and GLD both decreased by 4-100%. Mean gray value decreased by 13-98%. Intra-grader coefficient of repeatability for area was 2.2% and for GLD was 0.7%. Standard deviation of the differences observed were greater than standard deviation of intra-grader repeatability in all circumstances, suggesting that the differences were due to treatment effect, not variability in the measurement.
Conclusions :
SD-OCTA provides a reliable and objective way to monitor NV lesions, and may be useful in following patients’ response to treatment. Future automated algorithms for lesion size measurement and longitudinal change analyses may further optimize SD-OCTA for applications in clinical practice.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.