Bressler Susan B, Edwards Allison R, Andreoli Christopher M, Edwards Paul Andrew, Glassman Adam R, Jaffe Glenn J, Melia Michele, Sun Jennifer K
Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Jaeb Center for Health Research, Tampa, FL, USA.
Transl Vis Sci Technol. 2015 Jan 22;4(1):5. doi: 10.1167/tvst.4.1.5. eCollection 2015 Jan.
To evaluate the reproducibility of central subfield thickness (CST) and volume measurements from optical coherence tomography (OCT) images obtained with Zeiss Stratus and Optovue RTVue, and formulate equations to convert these measurements from RTVue to 'equivalent' Stratus values.
Cross-sectional observational study from 309 eyes of 167 participants with diabetes and at least one eye with central-involved diabetic macular edema (DME; Stratus CST ≥ 250 μm) that underwent two replicate Stratus scans followed by two replicate RTVue scans centered on the fovea.
The Bland-Altman coefficient of repeatability for relative change in CST (the degree of change that could be expected from measurement variability) was not significantly different on Stratus and RTVue scans (10% and 16%, respectively). The replicate Stratus CST was within 10% of the initial Stratus measurement 93% of the time; the CST conversion equation predicted a Stratus value calculated from the observed RTVue value within 10% of the observed Stratus thickness 91% of the time. Bland-Altman limit of agreement for relative change in CST between measurements observed on different machines was 23%, comparing predicted versus actual Stratus measurement.
RTVue thickness reproducibility appears similar to Stratus. Conversion equations to transform RTVue measurements to Stratus-equivalent values within 10% of the observed Stratus RT are feasible. CST changes greater than 10% when using the same machine or 20% when switching from Stratus to RTVue, after conversion to Stratus equivalents, are likely due to a true change beyond measurement error.
Conversion equations to translate central retinal thickness measurements between OCT instruments is critical to clinical trials.
评估使用蔡司Stratus和Optovue RTVue获取的光学相干断层扫描（OCT）图像中中心子场厚度（CST）和体积测量的可重复性，并制定将这些测量值从RTVue转换为“等效”Stratus值的方程。
对167名糖尿病患者的309只眼睛进行横断面观察研究，这些患者至少有一只眼睛患有累及中心的糖尿病性黄斑水肿（DME；Stratus CST≥250μm），先进行两次重复的Stratus扫描，然后以黄斑中心凹为中心进行两次重复的RTVue扫描。
CST相对变化的Bland-Altman重复性系数（可从测量变异性预期的变化程度）在Stratus和RTVue扫描中无显著差异（分别为10%和16%）。重复的Stratus CST在93%的时间内处于初始Stratus测量值的10%以内；CST转换方程预测，根据观察到的RTVue值计算出的Stratus值在91%的时间内处于观察到的Stratus厚度的10%以内。比较预测的Stratus测量值与实际测量值，不同机器上观察到的测量值之间CST相对变化的Bland-Altman一致性界限为23%。
RTVue厚度的可重复性似乎与Stratus相似。将RTVue测量值转换为Stratus等效值且误差在观察到的Stratus测量值的10%以内的转换方程是可行的。在转换为Stratus等效值后，使用同一台机器时CST变化大于10%，或从Stratus切换到RTVue时变化大于20%，可能是由于超出测量误差的真实变化。
在OCT仪器之间转换中央视网膜厚度测量的转换方程对临床试验至关重要。
