Abstract
Purpose :
Optical coherence tomography angiography (OCTA) allows for the quantification of retinal capillary density. However, there has been limited evaluation of the reliability of density mapping in various retinal conditions. The aim of this study is to evaluate the factors that affect the intra-individual reliability of retinal thickness and vascular density measurements using OCTA.
Methods :
A retrospective analysis was conducted to determine the intra-individual reliability of retinal thickness and vascular density measurements of split-spectrum amplitude-decorrelation angiography (SSADA) OCTA. OCTA (Avanti RTVue XR; Optovue, Fremont, CA) images were acquired by a single operator at a tertiary care center. Patients were selected based on retinal disease and three images were acquired, each being spaced 5 minutes apart. The capillary perfusion density (CPD) analysis provided CPD values and retinal thickness measurements of the superficial and deep retinal capillaries and values were recorded. Retinal thickness and CPD measurements of the perfusion density analysis were compared between time points and differences were calculated.
Results :
Thirty-four eyes of individual patients were imaged. Eighteen patients were female and the mean age of the whole cohort was 71 years (SD:±9.7 years). Approximately 73.5% of eyes (n=25) were phakic. Non-proliferative diabetic retinopathy (NPDR), proliferative diabetic retinopathy (PDR), non-exudative age-related macular degeneration (AMD) and central retinal vein occlusion (CRVO) were present in 14.7%, 11.8%, 11.8% and 11.8% of patients, respectively and 14.7% of eyes had no retinal pathology. The average signal strength across all eyes was 56.6 ± 9.5. The average percent deviation in parafoveal thickness for the various retinal diseases across all time points was 1.16% in BRVO, 1.80% in CRVO, 0.11% in dry AMD, 0.40% in PDR, and 1.59% in patients without retinopathy. The average percent deviation in foveal capillary perfusion density was 5.87% in BRVO, 7.36% in CRVO, 1.61% in dry AMD, 4.02% in PDR, and 3.12% in patients without retinal disease.
Conclusions :
For the majority of retinal diseases, the SSADA OCTA analysis is a reliable tool for evaluation of retinal perfusion. Deviation of results from the density analysis are most substantial in patients with vein occlusions and should be kept in mind when analyzing these images in prospective studies.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.