What is the role of optical coherence tomography angiography (OCT-A) in the workup of choroidal neovascularization (CNV)?

Updated: Jul 27, 2020
  • Author: Lihteh Wu, MD; Chief Editor: Andrew A Dahl, MD, FACS  more...
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Optical coherence tomography angiography (OCT-A) is a noninvasive imaging modality that visualizes the vascular anatomy of the fundus by detecting motion contrast between repeated OCT B-scans at the same site. Since the only moving objects in the fundus are the erythrocytes, the images produced represent a map of blood flow. OCT-A is depth resolved and permits differentiation of the different capillary plexuses.

OCT-A has several limitations, including a limited field of view, image artifacts, and inability to demonstrate leakage. Current en face OCT-A suffers from 2 major problems: flattening of the depth information within a given layer, causing loss of the vascular interrelationships within the layer, and the need for segmentation. In many eyes with pathologic changes, accurate segmentation is not possible because the layers cannot be readily identified. [23]

Since OCT-A does not require dye injection, it is much safer than fluorescein or indocyanine green angiography. Intravenous access is unnecessary, and there is no risk of anaphylaxis. With the current technology, the sensitivity of OCT-A for CNV detection varies from 50%-100%. [24, 25]

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