基于 OCTA 的脉络膜血流缺损定量分析中取片位置的影响
Impact of Slab Selection on Quantification of Choriocapillaris Flow Deficits by Optical Coherence Tomography Angiography.
机构信息
Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, California, USA; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA; Department of Ophthalmology, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Pusan National University School of Medicine, Yangsan, South Korea.
Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, California, USA; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
出版信息
Am J Ophthalmol. 2019 Dec;208:397-405. doi: 10.1016/j.ajo.2019.08.026. Epub 2019 Sep 5.
PURPOSE
To assess the impact of slab selection on quantitative measurements of choriocapillaris (CC) flow deficits (FDs) using optical coherence tomography angiography (OCTA).
DESIGN
Cross-sectional study.
METHODS
Using a swept-source OCTA device, en face slabs to isolate the CC were first generated using the manufacturer's default setting: a 20-μm-thick slab starting 29 μm posterior to the centerline of the automatically segmented retinal pigment epithelium (RPE) band. The inner and/or outer borders were then adjusted by 2-μm increments to generate CC slabs with a range of offsets relative to the center of the RPE band. FDs of the modified slabs were compared to that of the default slab.
RESULTS
Twenty-seven eyes of healthy subjects (mean age, 42.0 years) were prospectively enrolled. FD% increased when the slab was shifted outward by ≥4 μm and inward by 20 μm (P < .05). Fifteen eyes (55.6%) showed large hypointense regions precluding quantification when the slab was shifted inward by 20 μm. Those without hypointensity demonstrated a decrease in FD% when the slab was shifted inward by 10-18 μm (P < .05). When modulating slab thickness, CC FD% increased and decreased when the slab thickness became thinner or thicker by ≥8 μm, respectively (P < .05).
CONCLUSIONS
Quantitative CC parameters may be significantly influenced by small differences in the slab selection. Slab close to the RPE can be susceptible to segmentation errors. These findings highlight the importance of accurate, precise, and consistent slab definition to reliably generate quantitative CC metrics from OCTA.
目的
评估使用光相干断层扫描血管造影（OCTA）时，层厚选择对脉络膜毛细血管（CC）血流缺损（FD）定量测量的影响。
设计
横断面研究。
方法
使用扫频源 OCTA 设备，首先使用制造商的默认设置生成用于分离 CC 的面状层：从自动分割的视网膜色素上皮（RPE）带中心线向后 29μm 处开始，厚度为 20μm。然后，通过 2μm 的增量调整内界和/或外界，以生成与 RPE 带中心具有一定偏移范围的 CC 层。将修改后的层的 FD 与默认层进行比较。
结果
前瞻性纳入 27 只健康眼（平均年龄 42.0 岁）。当层向外偏移≥4μm 且向内偏移 20μm 时，FD%增加（P<.05）。当层向内偏移 20μm 时，15 只眼（55.6%）出现大的低信号区域，无法进行定量分析。当层向内偏移 10-18μm 时，无低信号的眼 FD%降低（P<.05）。当调节层厚度时，当层厚度变薄或变厚≥8μm 时，CC FD%分别增加和减少（P<.05）。
结论
定量 CC 参数可能会受到层选择中微小差异的显著影响。靠近 RPE 的层可能容易受到分割错误的影响。这些发现强调了准确、精确和一致的层定义对于从 OCTA 可靠地生成定量 CC 指标的重要性。
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