Artifacts observed in Optical Coherence Tomography Angiograp
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A Study was conducted to determine the prevalence of different types of artifacts seen in optical coherence tomography angiography (OCTA) images of healthy and glaucoma eyes and to evaluate the characteristics associated with the increased likelihood of obtaining poor quality images.

A total of 649 eyes of 368 healthy, glaucoma suspect, and glaucoma patients were included.

Angiovue high density (HD) and non-HD optic nerve head and macula OCTA images of participants were evaluated by 4 expert reviewers for the presence of different artifacts including eye movement, defocus, shadow, decentration, segmentation error, blink and Z offset in the superficial vascular layer. Each OCTA scan was designated to have good or poor quality based on the presence of artifacts. The association of demographic and ocular characteristics with the likelihood of obtaining poor quality OCTA images was evaluated using generalized linear mixed model.

Results:
--5263 OCTA images were evaluated. Overall, 33.9% of the OCTA images had poor quality. The majority of images with acceptable quality scores (QS more than 4) had no artifacts.

--Other images had one (13.6%) or two or more artifacts (9.8%). Older age, male gender, worse visual field mean deviation, absence of eye tracking and macular scan area were associated with a higher likelihood of obtaining poor quality images.

--In images with acceptable QS, the commercially available quality measures including QS and signal strength index had the area under the receiver operating characteristic curves of 0.65 and 0.70 to detect good quality images, respectively.

OCTA artifacts are common in low-resolution images, and their occurrence is influenced by ocular and patient characteristics. To ensure that OCTA images are correctly interpreted, a systematic scan analysis should be performed. Given the high prevalence of low quality OCTA images, if an obvious and correctable artifact is present on a captured image, the images should be re-acquired.

Source: https://www.aaojournal.org/article/S0161-6420(21)00241-4/fulltext?rss=yes
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