Abstract
Purpose:
Fluorescein angiography (FA) is the gold standard for measuring the area of choroidal neovascularization (CNV). Spectral-domain optical coherence tomography (SD-OCT) is increasingly used for monitoring CNV. We developed a methodology for evaluating the area of CNV on SD-OCT and compared to FA.
Methods:
We analyzed 17 treatment naïve subjects (17 eyes) with new-onset CNV secondary to age-related macular degeneration (AMD) enrolled in clinical trials. Subjects underwent FA and SD-OCT imaging studies. At the University of Wisconsin Fundus Photograph Reading Center, OCT scans were converted to DICOM images, allowing data from all SD-OCT machines to be displayed in the same software. OCT images were segmented for the inner limiting membrane, top of the retinal pigment epithelial (RPE) lesion complex and Bruchs’ membrane layers in a display and analysis platform (Huang, et al, PLoS One. 2013 Dec 26;8(12):e82922). Reading center graders reviewed each volume scan and edited the boundary line placement if required. The central subfield thickness (CSF) and total volume of the RPE lesion complex were obtained. A projection map of the segmented OCT was generated and the area of the RPE lesion complex was delineated using Image J software and subsequently compared to the area of CNV and lesion found on FA.
Results:
A total of 17 eyes were included in this study. The mean RPE lesion complex thickness in the CSF was 97.8 ± 57.6 µm with a grid volume of 1.0 mm3. The mean RPE lesion complex area on SD-OCT was 4.1 mm2 (SD 2.5). The mean CNV area on FA was 5.4 mm2 (SD 6.9) and the mean lesion area was 6.0 mm2 (SD 6.8). The mean difference between area of RPE lesion complex on OCT and CNV area on FA was 1.29 mm2 (CI -8.97, 11.55). When compared to the lesion area on FA, the mean difference was 1.87 mm2 (CI -8.09, 11.83).
Conclusions:
The use of SD-OCT was able to provide quantitative data about the area and volume of new CNV secondary to AMD. Area measurements from OCT correlated moderately with both CNV and lesion area on FA. Further studies using co-localization between the two modalities and follow-up studies will help evaluate the use of SD-OCT in assessing CNV status. In prospective clinical trials, these findings may substantiate the growing role of SD-OCT in the management of AMD and reduce the need for more invasive testing with FA.