Ophthalmology and Visual Sciences, Dalhousie University/Nova Scotia Health Authority, Halifax, Nova Scotia, Canada.
Ophthalmology and Visual Sciences, Dalhousie University/Nova Scotia Health Authority, Halifax, Nova Scotia, Canada
Br J Ophthalmol. 2020 Dec;104(12):1724-1729. doi: 10.1136/bjophthalmol-2019-315592. Epub 2020 Feb 27.
BACKGROUND/AIMS: Quantitative analysis of optical coherence tomography angiography (OCT-A) images requires a reproducible approach that accounts for sectoral loss. The objective of this study was to determine whether an index that accounts for both global (perfusion density, PD) and asymmetric loss of perfusion, rather than PD alone, more reliably measures loss of perfusion in patients with glaucoma.
We analysed macular OCT-A scans of 95 glaucoma patients and 59 control subjects. Two-dimensional projection images corresponding to the superficial vascular plexus were exported and analyses performed to calculate global PD and image asymmetry. An unsigned perfusion asymmetry index (PAI) that included PD and asymmetry (with 1:1 wt) was calculated. Perfusion density and PAI were compared with 10-2 visual field mean deviation and ganglion cell layer (GCL) thickness.
Median (IQR) visual field mean deviation was -1.73 (-3.76, 0.30) dB for the glaucoma group and 0.67 (0.16, 1.18) dB for the control group. The strength of the correlation with mean deviation was stronger for PAI (r=0.47), compared with PD (r=0.35), whereas with GCL thickness they were comparable (r=0.45 and 0.43, respectively). Compared with controls, mean PD was 12% lower in patients with glaucoma (0.27 vs 0.30), while PAI was 17% lower (0.40 vs 0.48). However, diagnostic accuracy of either PD or PAI was worse than GCL thickness.
While PAI yielded better correlation with mean deviation and GCL thickness, and a slightly improved separation between patients with glaucoma and healthy controls, diagnostic accuracy was inferior compared with GCL thickness.
背景/目的：定量分析光相干断层扫描血管造影（OCT-A）图像需要一种可重复的方法，该方法可以考虑到扇形损失。本研究的目的是确定一种既能反映整体（灌注密度，PD）又能反映灌注不对称损失的指数，而不仅仅是 PD，是否能更可靠地测量青光眼患者的灌注损失。
我们分析了 95 例青光眼患者和 59 例对照者的黄斑 OCT-A 扫描。导出与浅层血管丛对应的二维投影图像，并进行分析以计算全局 PD 和图像不对称性。计算包括 PD 和不对称性（1:1wt）的无符号灌注不对称指数（PAI）。将 PD 和 PAI 与 10-2 视野平均偏差和节细胞层（GCL）厚度进行比较。
青光眼组的中位（IQR）视野平均偏差为-1.73（-3.76，0.30）dB，对照组为 0.67（0.16，1.18）dB。与 PD（r=0.35）相比，PAI（r=0.47）与平均偏差的相关性更强，而与 GCL 厚度的相关性则相当（r=0.45 和 0.43）。与对照组相比，青光眼患者的平均 PD 降低了 12%（0.27 比 0.30），而 PAI 降低了 17%（0.40 比 0.48）。然而，PD 或 PAI 的诊断准确性均不如 GCL 厚度。
虽然 PAI 与平均偏差和 GCL 厚度的相关性更好，并且在青光眼患者和健康对照者之间的分离度略有提高，但与 GCL 厚度相比，其诊断准确性较低。
