Minimising retinal vessel artefacts in optical coherence tomography images

Golzan, SM; Avolio, A; Graham, SL

Minimising retinal vessel artefacts in optical coherence tomography images

Golzan, SM

Avolio, A Graham, SL

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Publication Type:: Journal Article
Citation:: Computer Methods and Programs in Biomedicine, 2011, 104 (2), pp. 206 - 211
Issue Date:: 2011-11-01

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Field	Value	Language
dc.contributor.author	Golzan, SM https://orcid.org/0000-0002-4479-3917	en_US
dc.contributor.author	Avolio, A	en_US
dc.contributor.author	Graham, SL	en_US
dc.date.available	2011-08-28	en_US
dc.date.issued	2011-11-01	en_US
dc.identifier.citation	Computer Methods and Programs in Biomedicine, 2011, 104 (2), pp. 206 - 211	en_US
dc.identifier.issn	0169-2607	en_US
dc.identifier.uri	http://hdl.handle.net/10453/115742
dc.description.abstract	Optical coherence tomography (OCT) is commonly used to investigate the layers of the retina including retinal nerve fiber layer (RNFL) and retinal pigment epithelium (RPE). OCT images are altered by vessels on the retinal surface producing artefacts. We propose a new approach to compensate for these artefacts and enhance quality of OCT images. A total of 28 (20 normal and 8 glaucoma subjects) OCT images were obtained using Spectralis (Heidelberg, Germany). Shadows were detected along the image and compensated by the A-Scan intensity difference from surrounding non-affected areas. Images were then segmented and the area and thickness of RNFL and RPE were measured and compared. 10 subjects were tested twice to determine the effect of this on reproducibility of measurements. Shadow-suppressed images reflected the profile of the retinal layers more closely when assessed qualitatively, minimising distortion. The segmentation of RNFL and RPE thickness demonstrated a mean change of 2.4% ± 1 and 6% ± 1 from the original images. Much larger changes were observed in areas with vessels. Reproducibility of RNFL thickness was improved, specifically in the higher density vessel location, i.e. inferior and superior. Therefore, OCT images can be enhanced by an image processing procedure. Vessel artefacts may cause errors in assessment of RNFL thickness and are a source of variability, which has clinical implications for diseases such as glaucoma where subtle changes in RNFL need to be monitored accurately over time. © 2011 Elsevier Ireland Ltd.	en_US
dc.relation.ispartof	Computer Methods and Programs in Biomedicine	en_US
dc.relation.isbasedon	10.1016/j.cmpb.2011.08.005	en_US
dc.subject.classification	Medical Informatics	en_US
dc.subject.mesh	Retinal Vessels	en_US
dc.subject.mesh	Humans	en_US
dc.subject.mesh	Glaucoma	en_US
dc.subject.mesh	Tomography, Optical Coherence	en_US
dc.subject.mesh	Artifacts	en_US
dc.subject.mesh	Case-Control Studies	en_US
dc.subject.mesh	Reproducibility of Results	en_US
dc.subject.mesh	Female	en_US
dc.subject.mesh	Male	en_US
dc.title	Minimising retinal vessel artefacts in optical coherence tomography images	en_US
dc.type	Journal Article
utslib.citation.volume	2	en_US
utslib.citation.volume	104	en_US
utslib.for	1113 Opthalmology and Optometry	en_US
utslib.for	0801 Artificial Intelligence and Image Processing	en_US
utslib.for	0903 Biomedical Engineering	en_US
utslib.for	0906 Electrical and Electronic Engineering	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Graduate School of Health
pubs.organisational-group	/University of Technology Sydney/Strength - CHT - Health Technologies
utslib.copyright.status	closed_access
pubs.issue	2	en_US
pubs.publication-status	Published	en_US
pubs.volume	104	en_US

Abstract:

Optical coherence tomography (OCT) is commonly used to investigate the layers of the retina including retinal nerve fiber layer (RNFL) and retinal pigment epithelium (RPE). OCT images are altered by vessels on the retinal surface producing artefacts. We propose a new approach to compensate for these artefacts and enhance quality of OCT images. A total of 28 (20 normal and 8 glaucoma subjects) OCT images were obtained using Spectralis (Heidelberg, Germany). Shadows were detected along the image and compensated by the A-Scan intensity difference from surrounding non-affected areas. Images were then segmented and the area and thickness of RNFL and RPE were measured and compared. 10 subjects were tested twice to determine the effect of this on reproducibility of measurements. Shadow-suppressed images reflected the profile of the retinal layers more closely when assessed qualitatively, minimising distortion. The segmentation of RNFL and RPE thickness demonstrated a mean change of 2.4% ± 1 and 6% ± 1 from the original images. Much larger changes were observed in areas with vessels. Reproducibility of RNFL thickness was improved, specifically in the higher density vessel location, i.e. inferior and superior. Therefore, OCT images can be enhanced by an image processing procedure. Vessel artefacts may cause errors in assessment of RNFL thickness and are a source of variability, which has clinical implications for diseases such as glaucoma where subtle changes in RNFL need to be monitored accurately over time. © 2011 Elsevier Ireland Ltd.

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http://hdl.handle.net/10453/115742