Rueb Kuna, Mynard Jonathan, Liu Richard, Wake Melissa, Vuillermin Peter, Ponsonby Anne-Louise, Zannino Diana, Burgner David P
1 University of Amsterdam, Amsterdam, Netherlands.
2 Murdoch Childrens Research Institute, Parkville, Australia.
Vasa. 2017 Jul;46(4):275-281. doi: 10.1024/0301-1526/a000630. Epub 2017 Mar 23.
Carotid intima-media thickness (CIMT), an ultrasonographic marker of cardiovascular risk, is increasingly used in adults and children. The choice of specific images used to quantify CIMT from a cine sequence is often based on image quality rather than on a consistent point in the cardiac cycle. This methodological study quantified the imprecision that may be introduced by variation of CIMT during the cardiac cycle.
Data from four-year-olds, 11 to 12-year-olds, and adults (n=30 each age group) were selected retrospectively from two population-derived studies. Far wall CIMT of the right common carotid artery was measured at end-diastole and peak systole using standardized protocols. All images were analysed using semi-automated edge-detection software.
In all age groups CIMT varied significantly during the cardiac cycle and was largest at end-diastole. The mean difference in CIMT between end-diastole and peak systole was greater in four-year-olds (38 μm; 95 % confidence interval (CI) 33 to 43 μm) and 11 to 12-year-olds (31 μm; CI 26 to 36 μm) than in adults (18 μm; CI 16 to 22 μm). Carotid IMT increased by 8.8 % (CI 7.7 to 9.8 %), 6.9 % (CI 5.8 to 8.1 %), and 3.8 % (CI 3.1 to 4.5 %) between minimum and maximum arterial diameter in four-year-olds, 11 to 12-year-olds, and adults, respectively. The greatest variation in CIMT during the cardiac cycle was observed in children (up to 14 %).
Inconsistent timing of CIMT measurement during the cardiac cycle is an avoidable source of imprecision, especially in children, in whom inter-individual differences are smallest. As CIMT is largest at end-diastole, this is the most appropriate time point for consistent and comparable measurements to be made.
颈动脉内膜中层厚度（CIMT）是心血管风险的超声检查标志物，在成人和儿童中应用越来越广泛。从电影序列中选择用于量化CIMT的特定图像通常基于图像质量，而非心动周期中的一致时间点。本方法学研究量化了心动周期中CIMT变化可能导致的不精确性。
从两项人群研究中回顾性选取4岁、11至12岁儿童及成人（各年龄组n = 30）的数据。使用标准化方案在舒张末期和收缩期峰值测量右侧颈总动脉远侧壁的CIMT。所有图像均使用半自动边缘检测软件进行分析。
在所有年龄组中，CIMT在心动周期中变化显著，且在舒张末期最大。4岁儿童（38μm；95%置信区间（CI）33至43μm）和11至12岁儿童（31μm；CI 26至36μm）舒张末期与收缩期峰值之间CIMT的平均差异大于成人（18μm；CI 16至22μm）。4岁、11至12岁儿童及成人中，动脉直径最小与最大时CIMT分别增加8.8%（CI 7.7至9.8%）、6.9%（CI 5.8至8.1%）和3.8%（CI 3.1至4.5%）。心动周期中CIMT变化最大的是儿童（高达14%）。
心动周期中CIMT测量时间不一致是不精确性的一个可避免来源，尤其是在个体差异最小的儿童中。由于CIMT在舒张末期最大，因此这是进行一致且可比测量的最合适时间点。
