Semi-manual Vessel Density Analysis on Optical Coherence Tomography Angiography Images of Healthy Adults

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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Semi-manual Vessel Density Analysis on Optical Coherence Tomography Angiography Images of Healthy Adults

Conditions
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Healthy

Intervention / Treatment
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* Device: Optical coherence tomography angiography (Zeiss Cirrus HD OCT 5000 AngioPlex)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy patients without eye disease Exclusion Criteria: incapacity any history or clinical evidence of retinal disease or glaucoma previous ocular surgery or laser photocoagulation optical media opacities that would disturb imaging

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 99 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Healthy patients<br>Healthy volunteers without retinal disease, glaucoma, previous ocular surgery, laser photocoagulation, or optical media opacities that would disturb imaging. | Device: Optical coherence tomography angiography (Zeiss Cirrus HD OCT 5000 AngioPlex)<br>* 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.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. | 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. | 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. | 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. | 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. | Through study completion, 1 year | 
| Vessel diameter index (VDI) measured by Shanbag tresholding 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 Shanbag tresholding technique. | 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. | 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. | Through study completion, 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. | Through study completion, 1 year |