Three-dimensional topographic angiography in chorioretinal vascular disease

To evaluate a new angiographic technique that offers three-dimensional imaging of chorioretinal vascular diseases.

Fluorescein (FA) and indocyanine green angiography (ICGA) were performed using a confocal scanning laser ophthalmoscope. Tomographic series with 32 images per set were taken over a depth of 4 mm at an image frequency of 20 Hz. An axial analysis was performed for each x/y position to determine the fluorescence distribution along the z-axis. The location of the onset of fluorescence at a defined threshold intensity was identified and a depth profile was generated. The overall results of fluorescence topography were displayed in a gray scale-coded image and three-dimensional relief.

Topographic angiography delineated the choriocapillary surface covering the posterior pole with exposed larger retinal vessels. Superficial masking of fluorescence by hemorrhage or absorbing fluid did not preclude detection of underlying diseases. Choroidal neovascularization (CNV) appeared as a vascular formation with distinct configuration and prominence. Chorioretinal infiltrates exhibited perfusion defects with dye pooling. Retinal pigment epithelium detachments (PEDs) demonstrated dynamic filling mechanisms. Intraretinal extravasation in retinal vascular disease was detected within a well-demarcated area with prominent retinal thickening.

Confocal topographic angiography allows high-resolution three-dimensional imaging of chorioretinal vascular and exudative diseases. Structural vascular changes (e.g., proliferation) are detected in respect to location and size. Dynamic processes (e.g., perfusion defects, extravasation, and barrier dysfunction) are clearly identified and may be quantified. Topographic angiography is a promising technique in the diagnosis, therapeutic evaluation, and pathophysiological evaluation of macular disease.