4.
Spectralis High Resolution Angiography/OCT
with Heidelberg Angiography
Carsten H. Meyer (Bonn)
To evaluate simultaneous confocal scanning laser ophthalmoscopy (cSLO) and high-speed,
high-resolution, spectral-domain optical coherence tomography (OCT) to visualize macular
pathologies.
Methods: OCT-images and simultaneous recording of fluorescein angiography, indocyanine
green (ICG) angiography, infrared, redfree, or fundus autofluorecence (FAF) images were
obtained with a novel imaging device (Spectralis HRA+OCT, Heidelberg Engineering,
Heidelberg, Germany). An optically pumped solid state laser generates the excitation wavelength
(488 nm) required for redfree, FAF and fluorescein angiography images. For ICG angiography
and infrared imaging diode laser sources at 790 and 815 nm are used. For OCT 40.000
A-scans are acquired per second with 7 μm depth and 14 μm lateral optical resolution. The B-scans with an angle of
30 degrees have a scan width up to 1.536 A-scans with a digital lateral resolution of 6 μm/pixel, a scan depth of 500 pixel
with 4 μm/pixel resolution and a scan rate up to 50 B-scans/sec. In addition volume scans can be obtained at 15, 20 and
30 degrees. An integrated eye tracking allows for live averaging of cSLO-images as well as OCT B- scans.
Results: Dry and vascular age-related macular degeneration, macular telangiectasia, retinal arterial and branch vein occlusion
were evaluated and cSLO and OCT frames correlated. Fluorescein and ICG-angiographic phenomena recorded in cSLO
images could be accurately analysed in corresponding OCT-cross sections. Abnormal FAF-signals were correlated to alterations
at the outer retinal/retinal pigment epithelial cell layer in high resolution OCT-scans. Three-dimensional OCT enabled
comprehensive retinal coverage. The imaging software accurately tracked eye movements. Averaging of live B-scans considerably
enhanced image quality.
Conclusion: The combined cSLO/OCT system allows for simultaneous recordings of topographic and tomographic images.
Particularly the pixel-to-pixel correlation between the confocal angiograms, FAF images and other imaging modes with the
OCT scans may provide a better understanding of the pathogenesis of retinal pathologies, and improve diagnosis and management
of patients with macular diseases.