Lang Gabriele E, Enders Christian, Loidl Max, Lang Gerhard K, Werner Jens Ulrich
Klinik für Augenheilkunde, Universitätsklinikum Ulm.
Klin Monbl Augenheilkd. 2017 Sep;234(9):1109-1118. doi: 10.1055/s-0043-112857. Epub 2017 Jun 19.
Optical coherence tomography angiography (OCTA) provides, non-invasively, a three-dimensional visualization of the microvasculature of the retina and choroid. However, image artifacts may occur in OCTA and have an impact on clinical interpretation. The aim of this article is to describe image artifacts of OCTA and to present a nomenclature. OCTA examinations were performed with the AngioPlex OCTA-technology in combination with the CIRRUS HD-OCT 5000 (Carl Zeiss Meditec, Inc., Dublin, USA) as well as with the PlexElite 9000 (Carl Zeiss Meditec, Inc., Dublin, USA). Typical artifacts identified in the OCTA images are described and their causes are explained. There are three main groups of artifacts that can be distinguished: (a) artifacts that are inherent in the OCTA technology and occur with all types of devices (projection artifacts, masking, unmasking, loss of signal); (b) artifacts caused by data and image processing algorithms and whose frequency or severity may depend on the device type used (segmentation artifacts, duplications of vessels); (c) motion artifacts that vary in frequency and severity depending on the type of device used, as different methods (e.g., eye tracker) are used to reduce them. The occurrence of artifacts is also dependent on patient cooperation, the clarity of the optical media, and the pathology of the retina. As in any other imaging method, artifacts also occur in OCTA images. Nevertheless, qualitative assessment of OCTA images is almost always possible and provides indispensable findings on the morphology and perfusion status of the retina and choroid. A good knowledge of possible artifacts, and a critical analysis of the complete OCTA data set, allows a correct interpretation and is essential for making a precise clinical diagnosis.
光学相干断层扫描血管造影（OCTA）能够非侵入性地提供视网膜和脉络膜微血管系统的三维可视化图像。然而，OCTA图像可能会出现伪像，并影响临床解读。本文旨在描述OCTA的图像伪像并提出一种命名法。使用AngioPlex OCTA技术结合CIRRUS HD - OCT 5000（美国都柏林卡尔蔡司医疗技术公司）以及PlexElite 9000（美国都柏林卡尔蔡司医疗技术公司）进行OCTA检查。描述了在OCTA图像中识别出的典型伪像并解释了其成因。可区分出三类主要伪像：（a）OCTA技术固有的、在所有类型设备中都会出现的伪像（投影伪像、掩蔽、去掩蔽、信号丢失）；（b）由数据和图像处理算法引起的伪像，其频率或严重程度可能取决于所使用的设备类型（分割伪像、血管重复）；（c）运动伪像，其频率和严重程度因所使用的设备类型而异，因为使用了不同的方法（如眼动追踪器）来减少它们。伪像的出现还取决于患者的配合、光学介质的清晰度以及视网膜的病变情况。与任何其他成像方法一样，OCTA图像中也会出现伪像。尽管如此，对OCTA图像进行定性评估几乎总是可行的，并且能提供关于视网膜和脉络膜形态及灌注状态不可或缺的信息。熟悉可能出现的伪像，并对完整的OCTA数据集进行批判性分析，有助于做出正确解读，对进行精确的临床诊断至关重要。
