Flower R W, Csaky K G, Murphy R P
The Retina Institute of Maryland, Towson, USA.
Retina. 1998;18(3):260-8. doi: 10.1097/00006982-199803000-00012.
Indocyanine green (ICG) angiograms of each of five patients with retinal pigment epithelium (RPE) detachments were made using first a Topcon fundus camera and then a Heidelberg scanning laser ophthalmoscope (SLO); for each patient, both types of angiograms were obtained on the same day. In each case, the serous fluid appeared bright throughout the fundus camera studies and dark throughout the SLO studies. This study sought to explain the disparity in the appearance of the lesions in the two kinds of images and to determine whether there was dye in the serous fluid.
Simple model eyes were constructed to demonstrate the effects of Mie light scatter and integrating sphere behavior of the sclera on ICG image formation by the fundus camera and SLO optics. Analysis was made of both the clinical angiograms and model eye images to structure an explanation for the disparate RPE detachment angiographic images.
Indocyanine green fluorescent light from choroidal vessels adjacent to the lesions and scattered by the turbid serous fluid accounted for the lesion brightness seen in the fundus camera images. The models confirmed that SLOs suppress scattered light.
The apparent fluorescence of serous fluid beneath RPE detachments in fundus camera early-phase ICG angiogram images is not attributable to the presence of dye; rather, it appears to be attributable to serous fluid light scatter of fluorescent light arising from adjacent fluorescent structures. This light scatter is a consequence of the fundus camera illumination and recording optics and is not present in SLO-generated images. The necessity of understanding such phenomena as absorption, diffraction, polarization, and scatter of light and routinely applying them to ICG angiogram interpretation is underscored when it is shown that they offer simple explanations for unusual or unexpected angiographic results, as in the case of the patients with RPE detachment discussed here.
对五名患有视网膜色素上皮（RPE）脱离的患者，先用拓普康眼底照相机，然后用海德堡扫描激光眼底镜（SLO）分别进行吲哚菁绿（ICG）血管造影；每位患者在同一天获得两种类型的血管造影图像。在每种情况下，在眼底照相机检查中，浆液在整个眼底均呈现明亮，而在SLO检查中则呈现黑暗。本研究旨在解释两种图像中病变外观的差异，并确定浆液中是否存在染料。
构建简单的模型眼，以演示米氏光散射和巩膜积分球行为对眼底照相机和SLO光学系统形成ICG图像的影响。对临床血管造影图像和模型眼图像进行分析，以构建对不同的RPE脱离血管造影图像的解释。
来自病变附近脉络膜血管并被浑浊浆液散射的吲哚菁绿荧光，是眼底照相机图像中病变亮度的原因。模型证实SLO可抑制散射光。
眼底照相机早期ICG血管造影图像中RPE脱离下方浆液的表观荧光并非由于染料的存在；相反，它似乎归因于来自相邻荧光结构的荧光的浆液光散射。这种光散射是眼底照相机照明和记录光学系统的结果，而在SLO生成的图像中不存在。当表明吸收、衍射、偏振和光散射等现象可为异常或意外的血管造影结果提供简单解释时，就像此处讨论的RPE脱离患者的情况一样，强调了理解这些现象并将其常规应用于ICG血管造影解释的必要性。
