Tanimoto Shuzou, Rodriguez-Granillo Gaston, Barlis Peter, de Winter Sebastiaan, Bruining Nico, Hamers Ronald, Knappen Michiel, Verheye Stefan, Serruys Patrick W, Regar Evelyn
Department of Cardiology, Thoraxcenter, Erasmus Medical Center Rotterdam, The Netherlands.
Catheter Cardiovasc Interv. 2008 Aug 1;72(2):228-35. doi: 10.1002/ccd.21482.
This study aims to examine observer-related variability of quantitative optical coherence tomography (OCT) derived measurements from both in vitro and in vivo pullback data.
Intravascular OCT is a new imaging modality using infrared light and offering 10 times higher image resolution (15 microm) compared to intravascular ultrasound. The quantitative analysis of in vivo intracoronary OCT imaging is complicated by the presence of blood, motion artifacts and the large quantity of information that has to be processed.
We developed a standardized, automated quantification process for intracoronary OCT pullback data with inter-observer variability assessed both in vitro by using postmortem human coronary arteries and in vivo by studying simple and complex coronary pathology and outcomes following stent implantation. The consensus between measurements by two observers was analyzed using the intraclass and interclass correlation coefficient and the reliability coefficients. Bland-Altman plots were generated to assess the relationship between variability and absolute measurements.
In vitro OCT assessment was performed in nine postmortem coronary arteries. The time needed for semiautomated contour detection of a 15-mm long coronary segment was approximately 40 min. The absolute and relative difference between lumen area measurements derived from two observers was low [0.02 +/- 0.10 mm(2); (0.3 +/- 0.5)% respectively] with excellent correlation confirmed by linear regression analysis (R(2) = 0.99; P < 0.001). Similarly, in vivo measurements demonstrated a high correlation with the main source of inter-observer variation occurring as a result of coronary dissection and motion artifact. The absolute and relative difference between measurements were 0.11 +/- 0.33 mm(2) (1.57 +/- 0.05)% for lumen area (R(2) = 0.98; P < 0.001), 0.17 +/- 0.68 mm(2) (1.44 +/- 0.08)% for stent area (R(2) = 0.94; P < 0.001), and 0.26 +/- 0.72 mm(2) (14.08 +/- 0.37)% for neointimal area (R(2) = 0.78; P < 0.001).
Highly accurate computer-assisted quantitative analysis ofintracoronary OCT pullbacks is feasible with low inter-observer variability. The presented approach allows for observer independent analysis of detailed vessel structures, and may be a valuable tool for future longitudinal studies incorporating OCT.
本研究旨在检测定量光学相干断层扫描（OCT）在体外和体内回撤数据中测量值的观察者相关变异性。
血管内OCT是一种利用红外光的新型成像方式，与血管内超声相比，其图像分辨率高10倍（15微米）。体内冠状动脉OCT成像的定量分析因血液的存在、运动伪影以及大量需要处理的信息而变得复杂。
我们为冠状动脉OCT回撤数据开发了一种标准化的自动定量分析流程，通过使用尸检人类冠状动脉在体外评估观察者间变异性，并通过研究简单和复杂冠状动脉病变以及支架植入后的结果在体内评估观察者间变异性。使用组内和组间相关系数以及可靠性系数分析两位观察者测量值之间的一致性。生成布兰德-奥特曼图以评估变异性与绝对测量值之间的关系。
在九条尸检冠状动脉上进行了体外OCT评估。半自动检测15毫米长冠状动脉节段轮廓所需时间约为40分钟。两位观察者得出的管腔面积测量值的绝对差异和相对差异都很低[分别为0.02±0.10平方毫米；（0.3±0.5）%]，线性回归分析证实相关性极佳（R² = 0.99；P < 0.001）。同样，体内测量显示相关性很高，观察者间差异的主要来源是冠状动脉夹层和运动伪影。管腔面积测量值的绝对差异和相对差异分别为0.11±0.33平方毫米（(1.57±0.05）%（R² = 0.98；P < 0.001），支架面积为0.17±0.68平方毫米（(1.44±0.08）%（R² = 0.94；P < 0.001），新生内膜面积为0.26±0.72平方毫米（(14.08±0.37）%（R² = 0.78；P < 0.001）。
冠状动脉OCT回撤的高精度计算机辅助定量分析是可行的，观察者间变异性较低。所提出的方法允许对详细的血管结构进行独立于观察者的分析，并且可能是未来纳入OCT的纵向研究的有价值工具。
