Three-dimensional angiography of classic and occult lesion types in choroidal neovascularization.

PURPOSE: To identify characteristic features of classic and occult choroidal neovascularization (CNV) by using a novel technique of topographic angiography for three-dimensional (3D) visualization.

METHODS: A confocal scanning laser ophthalmoscope (SLO, Heidelberg Retina Angiograph; Heidelberg Engineering, Dossenheim, Germany) was used to perform fluorescein (FA) and indocyanine green (ICGA) angiography in158 patients. Ninety-four eyes had predominantly classic and 64 eyes had occult lesions. With an image frequency of 20 Hz, a tomographic series of 32 images per set were taken over a depth of 4 mm. Axial analyses for each x/year position were performed, to determine the fluorescence distribution along the z-axis. After the axial location of hyperfluorescence was detected, a depth profile was generated. All results were integrated into a gray-scale-coded depth image and imaged as a 3D relief.

RESULTS: Characteristic features of classic and occult lesions were distinguished. Classic CNV appeared as a well-demarcated lesion with steep, prominent borders, often craterlike, and frequently surrounded by a halo, suggesting choroidal perfusion changes. Occult CNV was documented by 3D as a convex lesion with flat, ill-defined borders and without any surrounding halo. Topographic imaging is superior to conventional angiography regarding definition of lesion type, configuration, and extension, because masking phenomena do not interfere.

CONCLUSIONS: Topographic angiography allows a realistic 3D representation of CNV. Characteristic features based on the neovascular architecture and the differences in leakage behavior of different lesion types are clearly identified.