Unit of Fetal Medicine and Diagnosis, Department for Women and Child Health, Careggi University Hospital, University of Florence, Florence, Italy.
Department of Obstetrics and Gynaecology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands.
Prenat Diagn. 2017 Dec;37(12):1198-1202. doi: 10.1002/pd.5163. Epub 2017 Nov 8.
The primary aim of the study was to investigate intraobserver and interobserver reproducibility of uterine artery (UtA) pulsatility index (PI) in the third trimester of pregnancy. The secondary aim of the study was to examine whether high maternal body mass index (BMI) or gestational age (GA) influence the reliability of this measurement.
Singleton pregnancies in women with known BMI were recruited between 30 and 40 weeks. UtA PI Doppler measurements were performed prospectively, independently, and blindly by 2 Fetal Medicine Foundation-accredited operators. Intraobserver and interobserver reproducibility was assessed by concordance correlation coefficient (CCC) and intraclass correlation coefficient (ICC); Bland-Altman plots were built and limits of agreement (LoA) were calculated. The analysis was performed for both raw numbers and percentiles. To estimate the intraoperator and interoperator agreement in defining normal and pathological measurements, the assessments were divided in 2 categories-UtA PI <95th percentile/ ≥95th percentile-and Cohen's kappa coefficients were calculated. Results were interpreted according to the cutoffs reported by the True Reproducibility of Ultrasound Techniques review. Correlation between maternal BMI and GA and accuracy of UtA measurements was studied with Spearman's correlation coefficient.
Measurements were available in 101 women. For intraobserver reproducibility, ICCs and CCCs were calculated for raw values and percentiles and were 0.912 and 0.835, and 0.837 and 0.716, respectively. For interobserver reproducibility, ICCs and CCCs were 0.809 and 0.732, and 0.677 and 0.576, respectively. This indicates a poor-moderate reproducibility of third trimester UtA PI. LoA were also wide (from a minimum of -0.30-0.35 to a maximum of -0.53-0.62). Cohen's kappa coefficients were 0.478 and 0.418, showing a moderate intraoperator and interoperator agreement in distinguishing between normal and pathological values. No correlation was found between maternal BMI and GA and reproducibility of the measurements.
Intraobserver and interobserver reproducibility of third trimester UtA PI as assessed by ICC, CCC, and LoA is only moderate-poor. The agreement between operators in defining pathological and normal measurements is moderate.
本研究的主要目的是探讨在妊娠晚期测量子宫动脉（UtA）搏动指数（PI）的观察者内和观察者间的可重复性。本研究的次要目的是检验高母体体重指数（BMI）或孕龄（GA）是否会影响该测量的可靠性。
在 30 至 40 孕周时，招募了已知 BMI 的单胎妊娠妇女。由 2 名获得胎儿医学基金会认证的操作人员前瞻性地、独立地、盲目地进行 UtA PI 多普勒测量。采用一致性相关系数（CCC）和组内相关系数（ICC）评估观察者内和观察者间的可重复性；绘制 Bland-Altman 图并计算界限（LoA）。对原始数值和百分位数进行了分析。为了估计操作员在定义正常和病理测量值方面的一致性，将评估分为 2 类-UtA PI <95 百分位/≥95 百分位，并计算 Cohen's kappa 系数。结果根据 True Reproducibility of Ultrasound Techniques 综述报告的截止值进行解释。使用 Spearman 相关系数研究了母体 BMI 和 GA 与 UtA 测量值的准确性之间的相关性。
101 名妇女的测量值可用。对于观察者内可重复性，原始值和百分位数的 ICC 和 CCC 分别为 0.912 和 0.835，0.837 和 0.716。对于观察者间可重复性，ICC 和 CCC 分别为 0.809 和 0.732，0.677 和 0.576。这表明妊娠晚期 UtA PI 的可重复性较差。LoA 也很宽（从最低的-0.30-0.35 到最高的-0.53-0.62）。Cohen's kappa 系数分别为 0.478 和 0.418，表明操作员在区分正常和病理值方面具有中等程度的一致性。未发现母体 BMI 和 GA 与测量值的可重复性之间存在相关性。
通过 ICC、CCC 和 LoA 评估，妊娠晚期 UtA PI 的观察者内和观察者间的可重复性仅为中等-较差。操作员在定义病理和正常测量值方面的一致性为中等。
