Ghasemi Falavarjani Khalil, Al-Sheikh Mayss, Akil Handan, Sadda Srinivas R
Department of Ophthalmology, Doheny Eye Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.
Eye Research Center, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran.
Br J Ophthalmol. 2017 May;101(5):564-568. doi: 10.1136/bjophthalmol-2016-309104. Epub 2016 Jul 20.
To describe optical coherence tomography angiography (OCTA) image artefacts in eyes with and without ocular pathologies.
The OCTA images of healthy subjects and patients with age-related macular degeneration, diabetic retinopathy and retinal vascular occlusions were retrospectively reviewed. All OCTA images were obtained using a swept-source OCTA instrument (Triton, Topcon). The frequency of various image artefacts including segmentation, banding, motion, projection, masking, unmasking, doubling of the retinal vessels, blink, stretching, out-of-window and crisscross artefacts was assessed. The impact of the artefact on the grading of the images for the foveal avascular zone in deep and superficial retinal layers, capillary non-perfusion and choroidal neovascularisation (CNV) was evaluated.
OCTA images of 57 eyes of 48 subjects including 23 eyes (40.3%) with CNV, 13 eyes (22.8%) with dry age-related macular degeneration, 9 eyes (15.7%) with cystoid macular oedema due to diabetic retinopathy or retinal vein occlusion and 12 normal eyes (21.1%) were available for evaluation. At least one type of artefact was present in the images from 51 eyes (89.4%). Banding artefact, segmentation, motion, unmasking, blink, vessel doubling, masking and out-of-window artefacts were found in 51 (89.4%), 35 (61.4%), 28 (49.1%), 9 (15.8%), 5 (8.8%), 1 (1.7%), 1 eye (1.7%) and 1 eye (1.7%), respectively. Projection artefact, stretch artefact or crisscross artefact was not observed. Banding, motion and segmentation artefacts were statistically significantly more frequent in eyes with ocular pathology compared with control eyes (all p<0.001). Eyes with choroidal diseases had significantly higher rate of segmentation error in the choriocapillaris slab compared with eyes with only retinal disease (p=0.02). In nine eyes (17.6%), the artefacts were deemed severe enough by the graders to preclude accurate grading of the image.
Image artefacts occur frequently in OCTA images. The artefacts are more frequent in eyes with pathology.
描述有无眼部疾病的眼睛的光学相干断层扫描血管造影（OCTA）图像伪像。
回顾性分析健康受试者以及年龄相关性黄斑变性、糖尿病视网膜病变和视网膜血管阻塞患者的OCTA图像。所有OCTA图像均使用扫频源OCTA仪器（Topcon Triton）获得。评估包括分割、条带、运动、投影、掩蔽、解掩蔽、视网膜血管双影、眨眼、拉伸、窗口外和交叉伪像等各种图像伪像的出现频率。评估伪像对视网膜深层和浅层中心凹无血管区图像分级、毛细血管无灌注和脉络膜新生血管（CNV）的影响。
48名受试者的57只眼睛的OCTA图像可供评估，其中包括23只（40.3%）患有CNV的眼睛、13只（22.8%）干性年龄相关性黄斑变性的眼睛、9只（15.7%）因糖尿病视网膜病变或视网膜静脉阻塞导致的黄斑囊样水肿的眼睛以及12只正常眼睛（21.1%）。51只眼睛（89.4%）的图像中至少存在一种伪像。条带伪像、分割、运动、解掩蔽、眨眼、血管双影、掩蔽和窗口外伪像分别在51只（89.4%）、35只（61.4%）、28只（49.1%）、9只（15.8%）、5只（8.8%）、1只（1.7%）、1只眼睛（1.7%）和1只眼睛（1.7%）中发现。未观察到投影伪像、拉伸伪像或交叉伪像。与对照眼相比，有眼部疾病的眼睛中条带、运动和分割伪像在统计学上显著更频繁（所有p<0.001）。与仅患有视网膜疾病的眼睛相比，患有脉络膜疾病的眼睛在脉络膜毛细血管层的分割误差率显著更高（p=0.02）。在9只眼睛（17.6%）中，分级者认为伪像严重到足以妨碍对图像进行准确分级。
OCTA图像中经常出现图像伪像。这些伪像在有病变的眼睛中更频繁出现。
