School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Stockholm, Sweden.
Medical Image and Signal Processing Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
Microvasc Res. 2018 Nov;120:100-110. doi: 10.1016/j.mvr.2018.06.005. Epub 2018 Jun 27.
Nailfold capillaroscopy (NC) is a diagnostic imaging technique that is used to assess the blood capillary network in the nailfold area. NC is routinely used for patients with microcirculation problems, such as systemic sclerosis and other connective tissue diseases. Experts commonly use subjective evaluation as a reference point in images of nailfold video capillaroscopy, so it is important to reduce the inherent ambiguities in human judgment and diagnosis. Image quality is an important factor that affects measurement error and assessment time of NC images.
In this study, a new image enhancement technique was introduced and evaluated subjectively.
In total, 475 nailfold video capillaroscopy images from 18 healthy subjects and 41 systemic lupus erythematosus patients were used. The images were randomly divided into two sets, one each with 275 and 200. Eight independent observers who were familiar with the capillaroscopy technique participated in this study. The set of 275 images was evaluated by three observers with the forced-choice pairwise comparison method. Elliptic broken line (EBL) was used to count the number of capillaries. The intra- and inter-observer reliability of the original and enhanced images was evaluated on 200 images by five observers.
Except for eight images, all observers preferred the enhanced images in the visual quality comparison method. The intra-class correlation coefficient (ICC) of intra- and inter-observer reliability increased from 0.76-0.84 to 0.82-0.89, respectively, when using the enhancement method.
By improving the image quality, more capillary details will be visible, and an observer can document more details that may not be visible in the original image and can do so more efficiently.
甲襞毛细血管显微镜检查（NC）是一种用于评估甲襞区域毛细血管网络的诊断成像技术。NC 通常用于存在微循环问题的患者，如系统性硬化症和其他结缔组织疾病。专家通常将主观评估作为甲襞视频毛细血管镜图像的参考点，因此减少人类判断和诊断中的固有歧义非常重要。图像质量是影响 NC 图像测量误差和评估时间的重要因素。
本研究引入了一种新的图像增强技术并进行了主观评估。
共使用了 18 名健康受试者和 41 名系统性红斑狼疮患者的 475 个甲襞视频毛细血管显微镜检查图像。这些图像被随机分为两组，每组 275 张和 200 张。8 名熟悉毛细血管镜技术的独立观察者参与了这项研究。使用 275 张图像的组由 3 名观察者使用强制选择成对比较法进行评估。使用椭圆折线（EBL）计数毛细血管数量。五名观察者在 200 张图像上评估原始和增强图像的观察者内和观察者间可靠性。
除了 8 张图像外，所有观察者在视觉质量比较方法中都更喜欢增强后的图像。使用增强方法后，观察者内和观察者间可靠性的组内相关系数（ICC）分别从 0.76-0.84 增加到 0.82-0.89。
通过提高图像质量，可以更清楚地看到更多毛细血管细节，观察者可以记录更多原始图像中不可见的细节，并且可以更高效地进行记录。
