BACKGROUND Modern computed tomographic scanning can produce 4-dimensional images of the left atrial appendage (LAA). LAA function and morphology can then be measured, to plan interventions such as occlusion and to evaluate LAA flow for thrombogenic risk analysis. A current problem here is defining a reproducible boundary between the LAA and the left atrium. METHODS This study used retrospectively gated 4-dimensional computed tomographic data from 25 implantation and coronary artery imaging patients. In each patient, the LAA ostium was defined at multiple time points during the RR interval. To examine the reproducibility of the definition of the LAA ostium, 3 observers analyzed all time frames in each patient 3 times. Five nonconsecutive time frames from each patient were then compared using intraclass correlation coefficients to quantify the precision of the method across patients. The correlation of LAA volumes for each time frame of each patient was determined across the different observers (interobserver) and within each observer's own data sets (intraobserver). RESULTS The method was successful in 92% of patients. Two-way random-effect, absolute-agreement, single-measurement intraclass correlation coefficients for interobserver measurements were 0.984, 0.990, and 0.988, with intraobserver intraclass correlation coefficients of 0.989, 0.989, and 0.995. The intraclass correlation coefficient of all observations was 0.988. CONCLUSIONS Classification of the LAA ostium using a stepwise procedure identifying the coumadin ridge and 2 vascular landmarks in ECG-gated computed tomography provides a viable method of establishing a highly reproducible boundary between the atrium and LAA needed to obtain LAA metrics useful for procedure planning and measuring LAA function.

中文翻译：

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在计算机断层扫描中用于高度可重复测量左心耳容积的基于血管标志的方法。

背景技术现代计算机断层扫描可以产生左心耳（LAA）的4维图像。然后可以测量左心耳功能和形态，以计划干预措施，如闭塞，并评估左心耳流量以进行血栓形成风险分析。当前的一个问题是定义 LAA 和左心房之间的可重复边界。方法 本研究使用来自 25 名植入和冠状动脉成像患者的回顾性门控 4 维计算机断层扫描数据。在每个患者中，在 RR 间隔期间的多个时间点定义 LAA 口。为了检查 LAA 口定义的可重复性，3 名观察员对每位患者的所有时间范围进行了 3 次分析。然后使用组内相关系数比较每个患者的五个非连续时间范围，以量化该方法对患者的精确度。每个患者每个时间段的 LAA 体积的相关性在不同的观察者（观察者间）和每个观察者自己的数据集（观察者内）之间确定。结果 该方法在 92% 的患者中成功。观察者间测量的双向随机效应、绝对一致性、单测量组内相关系数为 0.984、0.990 和 0.988，观察者内组内相关系数为 0.989、0.989 和 0.995。所有观察的组内相关系数为 0.988。