Imaging of the parafoveal capillary network and its integrity analysis using fractal dimension

Biomedical Optics Express (Impact Factor: 3.65). 05/2011; 2(5):1159-68. DOI: 10.1364/BOE2.001159
Source: PubMed


Using a spectral domain OCT system, equipped with a broadband Ti:sapphire laser, we imaged the human retina with 5 µm x 1.3 µm transverse and axial resolution at acquisition rate of 100 kHz. Such imaging speed significantly reduces motion artifacts. Combined with the ultra-high resolution, this allows observing microscopic retinal details with high axial definition without the help of adaptive optics. In this work we apply our system to image the parafoveal capillary network. We demonstrate how already on the intensity level the parafoveal capillaries can be segmented by a simple structural high pass filtering algorithm. This data is then used to quantitatively characterize the capillary network of healthy and diseased eyes. We propose to use the fractal dimension as index for capillary integrity of pathologic disorders.

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Available from: Rainer A Leitgeb
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    • "Furthermore post processing algorithms to filter vessel structures out of intensity tomograms work well in the retina. This is due to the strong contrast of highly backscattering blood to the embedding transparent retinal tissue (Dittrich et al., 2009; Schmoll et al., 2011). Excellent results have been achieved by measuring the amount of signal decorrelation, which is a result of structural changes over time. "
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    • "Longitudinal assessment of the capillaries showed microaneurysm formation and disappearance as well as the formation of tiny capillary bends similar in appearance to intraretinal microvascular abnormalities. In vivo imaging of the capillary network has been also shown using an AO-SD-OCT [131–133]. The 3D information provided by OCT represents a major advantage compared to en face imaging techniques. "
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