Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
Transl Vis Sci Technol. 2021 Nov 1;10(13):16. doi: 10.1167/tvst.10.13.16.
To evaluate the mutual effect of widening the field of view and multiple en face image averaging on the quality of optical coherence tomography angiography (OCTA) images.
This prospective, observational, cross-sectional case series included 20 eyes of 20 healthy volunteers with no history of ocular or systemic disease. OCTA imaging of a 3 × 3-mm, 6 × 6-mm, and 12 × 12-mm area centered on the fovea was performed nine times using the PLEX Elite 9000. We acquired averaged OCTA images generated from nine en face OCTA images. The corresponding areas in the three scan sizes were evaluated for the original single-scanned OCTA images and averaged OCTA images both qualitatively and quantitatively. Quantitative measurements included vessel density (VD), vessel length density (VLD), fractal dimension (FD), and contrast-to-noise ratio (CNR).
Significant differences in VD, VLD, FD, and CNR (P < 0.001) were observed due to the mutual effect of averaging and differences in scan size. Both qualitative and quantitative evaluations indicated that the quality of 6 × 6-mm averaged images was equal to or better than that of 3 × 3-mm single-scanned images. However, the quality of 12 × 12-mm averaged images did not reach that of 3 × 3-mm single-scanned images.
To some extent, multiple en face OCTA image averaging can compensate for the deterioration in image quality caused by widening the field of view.
Multiple en face OCTA image averaging can be a technique for acquiring wider field OCTA images with good quality.
评估拓宽视野和多次面平均对光学相干断层扫描血管造影（OCTA）图像质量的相互影响。
本前瞻性、观察性、横断面病例系列研究纳入了 20 名无眼部或系统性疾病史的健康志愿者的 20 只眼。使用 PLEX Elite 9000 对以黄斑为中心的 3×3mm、6×6mm 和 12×12mm 区域进行 9 次 OCTA 成像。我们从 9 个面 OCTA 图像中获取平均 OCTA 图像。在三个扫描尺寸的相应区域中，对原始单扫描 OCTA 图像和平均 OCTA 图像进行定性和定量评估。定量测量包括血管密度（VD）、血管长度密度（VLD）、分形维数（FD）和对比噪声比（CNR）。
由于平均和扫描尺寸差异的相互作用，观察到 VD、VLD、FD 和 CNR 的显著差异（P<0.001）。定性和定量评估均表明 6×6mm 平均图像的质量与 3×3mm 单扫描图像相当或更好。然而，12×12mm 平均图像的质量并未达到 3×3mm 单扫描图像的质量。
在一定程度上，多次面 OCTA 图像平均可以弥补拓宽视野导致的图像质量恶化。
Yan Q, Wang Y, Guo J, et al. (2023) Mutual effect of widening the field of view and multiple en face image averaging on optical coherence tomography angiography images: a prospective study. Transl Vis Sci Technol 12:12.
