Abstract Purpose Fractal analysis can be used to quantitatively analyze the retinal microvasculature and might be a suitable method to quantify retinal capillary changes in sickle cell disease (SCD) patients. Retinal oximetry measurements might function as a proxy for the pathophysiology of cerebrovascular diseases. Moreover, hypoxia has an important role in the pathophysiology of diabetic and other retinopathies. However, little is known about the oximetry around the macula in SCD patients. With this study, we explored the feasibility to perform these quantified measurements in SCD patients. Methods Retinal microvascular and oximetry measurements were performed in eight SCD patients and eight healthy matched controls. Oximetry pictures and non-invasive capillary perfusion maps (nCPM) were obtained by the retinal function imager. Measurements were conducted twice on two different study days. Measured variables included monofractal dimension (Dbox), relative saturation, deoxygenated hemoglobin (deoxyHb), and oxygenated hemoglobin (oxyHb) concentration. Results No statistically significant differences in vessel density were found in the different annular zones (large vessels, p = 0.66; small vessels, p = 0.66) and anatomical quadrants (large vessels, p = 0.74; small vessels, p = 0.72). Furthermore, no significant between-group differences were found in the other different anatomical quadrants and annular zones around the fovea for relative saturation levels and deoxygenated Hb. However, the oxyHb levels were significantly lower in SCD patients, compared with those in matched controls in the temporal quadrants (p = 0.04; p = 0.02) and the superior nasal quadrant (p = 0.05). Conclusions Our study demonstrated the feasibility of multispectral imaging to measure retinal changes in oxygenation in both SCD patients and matched volunteers. The results suggest that in SCD patients before any structural microvascular changes in the central retina are present, functional abnormalities can be observed with abnormal oximetry measurements.

中文翻译：

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镰状细胞病患者和匹配的健康志愿者的视网膜血氧饱和度和毛细血管图的分形分析

摘要 目的分形分析可用于定量分析视网膜微血管系统，并且可能是量化镰状细胞病（SCD）患者视网膜毛细血管变化的合适方法。视网膜血氧饱和度测量可以作为脑血管疾病病理生理学的代理。此外，缺氧在糖尿病和其他视网膜病变的病理生理学中具有重要作用。然而，人们对 SCD 患者黄斑周围的血氧饱和度知之甚少。通过这项研究，我们探讨了在 SCD 患者中进行这些量化测量的可行性。 方法对 8 名 SCD 患者和 8 名健康匹配对照进行了视网膜微血管和血氧饱和度测量。通过视网膜功能成像仪获得血氧饱和度图片和无创毛细血管灌注图（nCPM）。在两个不同的研究日进行两次测量。测量变量包括单分形维数 (Dbox)、相对饱和度、脱氧血红蛋白 (deoxyHb) 和氧合血红蛋白 (oxyHb) 浓度。 结果在不同的环形区域（大血管、p= 0.66; 小船只，p= 0.66）和解剖象限（大血管，p= 0.74; 小船只，p= 0.72）。此外，在其他不同的解剖象限和中央凹周围的环形区域中，相对饱和度和脱氧血红蛋白没有发现显着的组间差异。然而，与匹配对照者相比，SCD 患者颞象限的 oxyHb 水平显着降低（p= 0.04;p= 0.02) 和上鼻象限 (p= 0.05）。 结论我们的研究证明了多光谱成像测量 SCD 患者和匹配志愿者视网膜氧合变化的可行性。结果表明，在 SCD 患者中，在中央视网膜出现任何结构性微血管变化之前，可以通过异常的血氧饱和度测量来观察到功能异常。