Sensitivity and Specificity of OCT Angiography to Detect Choroidal Neovascularization

Abstract

PurposeTo determine the sensitivity and specificity of OCT angiography (OCTA) in the detection of choroidal neovascularization (CNV) in age-related macular degeneration (AMD). DesignProspective case series. SubjectsA prospective series of 72 eyes were studied, which included eyes with treatment-naive CNV due to AMD, non-neovascular AMD, and normal controls. MethodsAll eyes underwent OCTA with a spectral domain OCT. The 3-dimensional angiogram was segmented into separate en face views including the inner retinal angiogram, outer retinal angiogram, and choriocapillaris angiogram. Detection of abnormal flow in the outer retina served as candidate CNV with OCTA. Masked graders reviewed structural OCT alone, en face OCTA alone, and en face OCTA combined with cross-sectional OCTA for the presence of CNV. Main Outcome MeasureThe sensitivity and specificity of CNV detection compared to the gold standard of fluorescein angiography and OCT was determined for structural spectral domain OCT alone, en face OCTA alone, and with en face OCTA combined with cross-sectional OCTA. ResultsOf 32 eyes with CNV, both graders identified 26 true positives with en face OCTA alone, resulting in a sensitivity of 81.3%. Four of the 6 false negatives had large subretinal hemorrhage and sensitivity improved to 94% for both graders if eyes with subretinal hemorrhage were excluded. The addition of cross-sectional OCTA along with en face OCTA improved the sensitivity to 100% for both graders. Structural OCT alone also had a sensitivity of 100%. The specificity of en face OCTA alone was 92.5% for grader A and 97.5% for grader B. The specificity of structural OCT alone was 97.5% for grader A and 85% for grader B. Cross-sectional OCTA combined with en face OCTA had a specificity of 97.5% for grader A and 100% for grader B. ConclusionsSensitivity and specificity for CNV detection with en face OCTA combined with cross-sectional OCTA approaches that of the gold standard of fluorescein angiography with OCT, and it is better than en face OCTA alone. Structural OCT alone has excellent sensitivity for CNV detection. False positives from structural OCT can be mitigated with the addition of flow information with OCTA.