Abstract

P 254

Comparison of quantitative image analysis results of optical coherence tomography images from Zeiss Stratus and Heidelberg Spectralis devices

Christoph Tappeiner1, Johannes Fleischhauer1, Sebastian Wolf1, Daniel Barthelmes2
1Universitäts-Augenklinik, Inselspital Bern, Bern, Switzerland, 2Universitätsklinik für Augenheilkunde, Universitätsspital Zürich (USZ), Zürich, Switzerland

Objective
To compare the results of quantitative image analysis of images from two different optical coherence tomography (OCT) devices and to evaluate the impact of media opacities on the image quality and image analysis results in both OCT devices.
Methods
Horizontally oriented macular OCT images, centered in the fovea, were acquired in 12 eyes of 6 healthy volunteers with both the Zeiss Stratus and the Heidelberg Engineering Spectralis OCT devices. Images were recorded without and while placing neutral density filters of increasing density between the OCT device and the eye to be examined. Raw data were exported from both devices and a quantitative image analysis was performed using a custom software to identify highly reflective layers within the OCT images as peaks within each single line-scan. The number of peaks and their respective reflectivities were analyzed.
Results
The quantitative image analysis gave similar results for both the Stratus and Spectralis device in the presence of clear optic media - the number of peaks detected in each line scan were identical and relation of reflectivities between the peaks were similar. Analysis of images acquired using the ND filters showed that in images recorded with the Stratus device, a linear decrease of reflectivity for all retinal layers occured while the relation of the different reflectivities was unchanged. Contrary to that, images recorded using the Spectralis device showed an increase in reflectivity of the less reflective retinal layers while the highly reflective layers retained their reflectivity leading to a change of the initial relations of the reflectivity of the different retinal layers.
Conclusions
In the presence of clear optic media, both OCT devices show similar results for quantification, while in the presence of simulated media opacities, the properties of images differ significantly between the two systems. Whenever performing quantitative OCT image analysis with the Spectralis device, the effect of the changing relations of reflectivities has to be considered.

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