Abstract

SA.09.06

Simultaneous imaging of macular diseases with a combined scanning laser angiography/fundus autoflourescence and high-resolution, spectral-domain optical coherence tomography imaging system

Helb H.-M., Charbel Issa P., Fleckenstein M., Eter N., Scholl H. P. N., Holz F. G.
Department of Ophthalmology, University of Bonn, Bonn

Objective: To demonstrate a novel retinal imaging tool that combines various modes of scanning laser ophthalmoscopy with spectral-domain optical coherence tomography (OCT) for visualization of macular diseases.
Methods: Images were obtained with a combined instrument for confocal scanning laser ophthalmoscopy (SLO) and spectral domain OCT (HRA-OCT Spectralis, Heidelberg Engineering, Heidelberg, Germany). Imaging modes allow simultaneous acquisition of fluorescein angiography (FA), fundus autoflourescence (FAF), infrared (IR), as well as redfree (RF) and OCT. 40.000 A-scans with 7 µm depth and 14 µm lateral resolution are recorded per second. B-scans encompass an angle of 30 degrees at a scan width of 1.536 (or 768) A-scans, lateral resolution of 6 (or 11) µm/pixel digital at a scan rate of 26 (or 50) B-scans/sec. Combined SLO-OCT images were obtained in patients with various macular pathologies.
Results: The combination of the SLO imaging modes with OCT allowed precise spatial correlation of FA, FAF, IR or RF SLO images with OCT findings. High-definition high-transverse pixel density OCT images allowed for accurate visualization of photoreceptor and pigment epithelial morphology, as well as fine intraretinal and epiretinal structures. Three-dimensional OCT enabled comprehensive retinal coverage, reduced sampling errors, and enabled assessment of 3-dimensional pathology. Intraretinal diseases were identified by their specific location in different layers of the neurosensory ultrastructure. The microarchitecture of choroidal neovascularization is distinctly imaged, and related leakage could be identified.
Conclusions: This new technology with a merge of two diagnostic modalities will become a useful tool for elucidating disease pathogenesis and improving diagnosis and management of macular disorders. High-definition 3-dimensional imaging using high-speed ultrahigh-resolution OCT improves image quality, retinal coverage, and registration. Precise pixel-to-pixel registration of FA-images and OCT together with automated alignment will be particular helpful for longitudinal assessment e.g. following therapeutic intervention in neovascular AMD.

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