Purpose of the study is to examine the vessel density of healthy adults' optical coherence tomography angiography images with two semi-manual methods and an automated quantification program.
Optical coherence tomography angiography (OCTA) is a software upgrade on conventional spectral-domain or swept-source optical coherence tomography devices that enables non-invasive, dye-free, three dimensional analysis of the retinal vessels. Vessel density is a very important parameter almost in all retinal disorders. In the recent past, automated quantification software was built into some OCTA devices which can automatically calculate the retinal vessel density as well. In this study two semi-manual techniques are used in order to analyze the vessel density of healthy subjects' OCTA images. Vessel density is also measured with a new automated quantification program, and results of the three methods are compared. OCT machines are approved in the EU and the US and are not experimental devices. The device used in this study is the commercially available Zeiss Cirrus HD OCT Angioplex 5000 that operates with spectral-domain technology.
Study Type
OBSERVATIONAL
Enrollment
39
Non-invasive, non-contact optical coherence tomography angiography scans of the retina are done per built-in device protocol using the Zeiss Cirrus HD OCT 5000 AngioPlex machine.
Semmelweis University, Department of Ophthalmology
Budapest, Hungary
Vessel density (VD) measured by Mexican Hat filtering technique
Following standard OCTA imaging with Zeiss Cirrus Angioplex, images are transferred to ImageJ and proportion of the vessels and the total image area (white pixels2/total number of pixels2) is calculated using Mexican Hat filtering technique.
Time frame: Through study completion, 1 year
Skeleton density (SD) measured by Mexican Hat filtering technique
Following standard OCTA imaging with Zeiss Cirrus Angioplex, images are transferred to ImageJ and length of blood vessels (white skeletonized pixels/total number of pixels2) is calculated using Mexican Hat filtering technique.
Time frame: Through study completion, 1 year
Vessel diameter index (VDI) measured by Mexican Hat filtering technique
Represents the average vessel caliber (two dimensional white pixels in the binarized image/one dimensional white pixels in the skeletonized image or VD/SD) using Mexican Hat filtering technique.
Time frame: Through study completion, 1 year
Vessel density (VD) measured by Shanbag tresholding technique
Following standard OCTA imaging with Zeiss Cirrus Angioplex, images are transferred to ImageJ and proportion of the vessels and the total image area (white pixels2/total number of pixels2) is calculated using Shanbag tresholding technique.
Time frame: Through study completion, 1 year
Skeleton density (SD) measured by Shanbag tresholding technique
Following standard OCTA imaging with Zeiss Cirrus Angioplex, images are transferred to ImageJ and length of blood vessels (white skeletonized pixels/total number of pixels2) is calculated using Shanbag tresholding technique.
Time frame: Through study completion, 1 year
Vessel diameter index (VDI) measured by Shanbag tresholding technique
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Represents the average vessel caliber (two dimensional white pixels in the binarized image/one dimensional white pixels in the skeletonized image or VD/SD) using Shanbag tresholding technique.
Time frame: Through study completion, 1 year
Vessel density (VD) measured by Angioplex Metrix
Following standard OCTA imaging with Zeiss Cirrus Angioplex measurement is done by built-in non-disclosed VD algorithm owned by Zeiss.
Time frame: Through study completion, 1 year
Skeleton density (SD) measured by Angioplex Metrix
Following standard OCTA imaging with Zeiss Cirrus Angioplex measurement done by built-in non-disclosed SD algorithm owned by Zeiss.
Time frame: Through study completion, 1 year
Comparison of results obtained by the three quantification techniques
Comparison of VD and SD (see above) obtained by Mexican Hat filtering technique, Shanbag tresholding technique and built-in Zeiss proprietary algorithm.
Time frame: Through study completion, 1 year