Moussa Magdy, Leila Mahmoud, Moussa Omar, Hashem Ahmed Osama
Ophthalmology Department, Faculty of Medicine, Tanta University, Tanta, Egypt.
MEDIC Eye Center, Tanta, Egypt.
Clin Ophthalmol. 2021 Feb 25;15:825-834. doi: 10.2147/OPTH.S294204. eCollection 2021.
To assess the efficacy of customized slab segmentation in eliminating projection artifacts in swept-source optical coherence tomography angiography (SS-OCTA) images of Best vitelliform macular dystrophy (BVMD).
Prospective case series including different stages of BVMD. We analyzed SS-OCTA images for flow signals in the outer retina and coregistered B-scan images for distortion of the segmentation slabs defining the outer retina. We applied a customized method for slab realignment whenever BVMD lesions produced distortion of the slabs. Afterward, we checked the images to determine whether the previously noted flow signal had persisted or disappeared, described as "true flow" or "pseudoflow", respectively. Categorical variables were analyzed with X or Fisher's exact tests, while quantitative variables were analyzed with independent -test at <0.05.
The study included 39 eyes of 22 patients. We detected BVMD patterns I (dome-shaped hyperreflective lesion without neurosensory retinal detachment), II (knob-like hyperreflective lesion with localized neurosensory retinal detachment), and III (heterogeneous scattered hyperreflective material) in 49%, 23%, and 28% of eyes, respectively. Pseudoflow was evident mostly in eyes with pattern II lesions, presence of flow signal within BVMD lesions, and lesions whose height represented >80% of the retinal thickness (<0.001).
Customized slab segmentation is effective in eliminating projection artifact in SS-OCTA images of BVMD.
Projection artifact is a significant confounding factor in emerging SS-OCTA technology through production of pseudoflow signals that can lead to misinterpretation of images of BVMD lesions. The present study proposes a customized method for correction of segmentation errors to eliminate projection artifacts in SS-OCTA images of BVMD patients.
评估定制化层片分割在消除Best卵黄样黄斑营养不良（BVMD）扫频光学相干断层扫描血管造影（SS-OCTA）图像中投影伪影方面的效果。
前瞻性病例系列研究，纳入不同阶段的BVMD患者。我们分析SS-OCTA图像中视网膜外层的血流信号，并分析与之配准的B扫描图像中定义视网膜外层的层片分割的变形情况。每当BVMD病变导致层片变形时，我们应用一种定制的层片重新对齐方法。之后，我们检查图像以确定先前记录的血流信号是持续存在还是消失，分别称为“真血流”或“假血流”。分类变量采用X检验或Fisher精确检验进行分析，定量变量采用独立样本t检验进行分析，P<0.05。
该研究纳入了22例患者的39只眼。我们分别在49%、23%和28%的眼中检测到BVMD I型（无神经感觉视网膜脱离的穹顶状高反射病变）、II型（伴有局限性神经感觉视网膜脱离的瘤状高反射病变）和III型（异质性散在高反射物质）。假血流在II型病变、BVMD病变内存在血流信号以及病变高度占视网膜厚度>80%的眼中最为明显（P<0.001）。
定制化层片分割可有效消除BVMD的SS-OCTA图像中的投影伪影。
投影伪影是新兴的SS-OCTA技术中的一个重要混杂因素，它会产生假血流信号，可能导致对BVMD病变图像的错误解读。本研究提出了一种定制方法来校正分割误差，以消除BVMD患者SS-OCTA图像中的投影伪影。
