School of Biomedical Informatics, University of Texas Health Science Center, Houston, Texas, USA.
Invest Ophthalmol Vis Sci. 2011 Jul 1;52(7):4717-25. doi: 10.1167/iovs.10-6303.
To evaluate digital photography parameters affecting comparability with the Early Treatment Diabetic Retinopathy Study (ETDRS) film protocol for diabetic retinopathy (DR) severity grading.
ETDRS protocol photographs and four variations of digital images (uncompressed stereoscopic, compressed stereoscopic, uncompressed monoscopic, and uncompressed monoscopic wide-angle mosaic) of 152 eyes were independently evaluated by using ETDRS classifications. Digital formats were compared to film and each other for agreement on severity level, DR presence at ascending threshold, presence of the DR index lesion, and repeatability of grading. Study parameters included image resolution sufficient to distinguish small lesions, color balancing of digital images to film, documenting essential ETDRS classification retinal regions, similar magnification, and supplementary green-channel viewing.
The κ statistic was substantial or near substantial between all digital formats and film for classifying severity levels (κ = 0.59-0.62; κ(w) [linear weighted] = 0.83-0.87). The distribution of DR levels in all digital formats was not significantly different from that of the film (Bhapkar test, P = 0.09-0.44). The κ among digital formats for severity level was also substantial or near substantial (κ = 0.58-0.76, κ(w) = 0.82-0.92). Differences between digital formats and film for grading severity level, severity threshold, or index lesions were not significant. The repeatability of grading between readers using film and all digital formats was also similar.
Digital format variations compared favorably with film for DR classification. Translating film characteristics (resolution, color/contrast) and protocol (magnification, retinal regions) to digital equivalents and augmentation of full color with green-channel viewing most likely contributed to the results.
评估影响糖尿病视网膜病变（DR）严重程度分级与糖尿病眼病早期治疗研究（ETDRS）胶片协议可比性的数字摄影参数。
对 152 只眼的 ETDRS 胶片协议照片和四种数字图像（未压缩立体、压缩立体、未压缩单目和未压缩广角镶嵌）进行独立评估，使用 ETDRS 分类进行评估。将数字格式与胶片和彼此进行比较，以评估严重程度水平、递增阈值处的 DR 存在情况、DR 指数病变的存在情况以及分级的可重复性。研究参数包括足以区分小病变的图像分辨率、数字图像与胶片的颜色平衡、记录 ETDRS 分类视网膜区域的基本情况、相似的放大倍数和补充绿通道查看。
在所有数字格式与胶片之间，分类严重程度的 κ 统计值均为中等或接近中等（κ=0.59-0.62；κ（w）[线性加权]=0.83-0.87）。所有数字格式的 DR 分级分布与胶片无显著差异（Bhapkar 检验，P=0.09-0.44）。数字格式之间严重程度分级的 κ 值也为中等或接近中等（κ=0.58-0.76，κ（w）=0.82-0.92）。数字格式与胶片之间在分级严重程度、严重程度阈值或指数病变方面的差异无统计学意义。使用胶片和所有数字格式进行分级的读者之间的可重复性也相似。
数字格式在 DR 分类方面与胶片相比具有优势。将胶片特性（分辨率、颜色/对比度）和协议（放大倍数、视网膜区域）转换为数字等效物，并通过绿通道查看增加全彩色可能是导致这些结果的原因。
