McCloskey Kate, Ponsonby Anne-Louise, Carlin John B, Jachno Kim, Cheung Michael, Skilton Michael R, Koleff Jane, Vuillermin Peter, Burgner David
Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia.
Cardiovasc Ultrasound. 2014 Jun 3;12:18. doi: 10.1186/1476-7120-12-18.
Aortic intima-media thickness measured by transabdominal ultrasound (aIMT) is an intermediate phenotype of cardiovascular risk. We aimed to (1) investigate the reproducibility of aIMT in a population-derived cohort of infants; (2) establish the distribution of aIMT in early infancy; (3) compare measurement by edge-detection software to that by manual sonographic calipers; and (4) assess the effect of individual and environmental variables on image quality.
Participants were term infants recruited to a population-derived birth cohort study. Transabdominal ultrasound was performed at six weeks of age by one of two trained operators. Thirty participants had ultrasounds performed by both operators on the same day. Data were collected on environmental (infant sleeping, presence of a sibling, use of sucrose, timing during study visit) and individual (post-conception age, weight, gender) variables. Two readers assessed image quality and measured aIMT by edge-detection software and a subset by manual sonographic calipers. Measurements were repeated by the same reader and between readers to obtain intra-observer and inter-observer reliability.
Aortic IMT was measured successfully using edge-detection in 814 infants, and 290 of these infants also had aIMT measured using manual sonographic calipers. The intra-reader intra-class correlation (ICC) (n = 20) was 0.90 (95% CI 0.76, 0.96), mean difference 1.5 μm (95% LOA -39, 59). The between reader ICC using edge-detection (n = 20) was 0.92 (95% CI 0.82, 0.97) mean difference 2 μm (95% LOA -45.0, 49.0) and with manual caliper measurement (n = 290) the ICC was 0.84 (95% CI 0.80, 0.87) mean difference 5 μm (95% LOA -51.8, 61.8). Edge-detection measurements were greater than those from manual sonographic calipers (mean aIMT 618 μm (50) versus mean aIMT 563 μm (49) respectively; p < 0.001, mean difference 44 μm, 95% LOA -54, 142). With the exception of infant crying (p = 0.001), no associations were observed between individual and environmental variables and image quality.
In a population-derived cohort of term infants, aIMT measurement has a high level of intra and inter-reader reproducibility. Measurement of aIMT using edge-detection software gives higher inter-reader ICC than manual sonographic calipers. Image quality is not substantially affected by individual and environmental factors.
经腹超声测量的主动脉内膜中层厚度（aIMT）是心血管风险的一种中间表型。我们旨在：（1）在一个源自人群的婴儿队列中研究aIMT的可重复性；（2）确定婴儿早期aIMT的分布情况；（3）将边缘检测软件测量结果与手动超声卡尺测量结果进行比较；（4）评估个体和环境变量对图像质量的影响。
参与者为入选源自人群的出生队列研究的足月儿。由两名经过培训的操作人员之一在婴儿6周龄时进行经腹超声检查。30名参与者在同一天由两名操作人员分别进行超声检查。收集了有关环境（婴儿睡眠状态、是否有兄弟姐妹、是否使用蔗糖、研究访视期间的时间）和个体（孕龄、体重、性别）变量的数据。两名阅片者评估图像质量，并通过边缘检测软件测量aIMT，一部分还通过手动超声卡尺测量。由同一名阅片者以及不同阅片者重复测量，以获得观察者内和观察者间的可靠性。
使用边缘检测成功测量了814名婴儿的主动脉IMT，其中290名婴儿还通过手动超声卡尺测量了aIMT。阅片者内组内相关系数（ICC）（n = 20）为0.90（95%CI 0.76，0.96），平均差异为1.5μm（95%一致性界限 -39，59）。使用边缘检测的阅片者间ICC（n = 20）为0.92（95%CI 0.82，0.97），平均差异为2μm（95%一致性界限 -45.0，49.0），而使用手动卡尺测量（n = 290）时ICC为0.84（95%CI 0.80，0.87），平均差异为5μm（95%一致性界限 -51.8，61.8）。边缘检测测量结果大于手动超声卡尺测量结果（aIMT平均值分别为618μm（50）和563μm（49）；p < 0.001，平均差异为44μm，95%一致性界限 -54，142）。除婴儿哭闹外（p = 0.001），未观察到个体和环境变量与图像质量之间存在关联。
在一个源自人群的足月儿队列中，aIMT测量具有较高的阅片者内和阅片者间可重复性。使用边缘检测软件测量aIMT比手动超声卡尺具有更高的阅片者间ICC。图像质量未受到个体和环境因素的实质性影响。
