DISCUSSION
This study reports the largest multicenter data collection for development of 3DE z-scores for LV volumes and function in healthy children using the semi-automated quantification method. Seventy-nine percent of the 3D datasets were able to be analyzed at the core laboratory, similar to another multicenter study in the pediatric age group 8. Krell et al. reported having a feasibility of 74% in their smaller multicenter study. Kuebler et al reported normative LV volume and functional values in 238 pediatric subjects of different age group and body surface area 9. However, only 14% of their subjects were under the age of 5 (34/238)9. Our study is notable in that 27% (141/523) of the subjects were under 5 years and 18% were less than 3 years of age. Hence this study provides important normative 3D LV volumetric data in this very young age group. Cantinotti et al. studied 800 Italian healthy children and reported excellent overall feasibility of 91%; however, feasibility for smaller children with BSA less than 0.5 was 68% to 80% respectively 10.
Prior studies from Kuebler et al. and Cantinotti et al. have described pediatric normative LV volumes and function derived from single centers9,10. Our study is a normative data from multiple centers to improve generalizability. The curvilinear relationship between LV volumes and BSA is similar to previous studies finding of LV volumes indexed to the BSA showing a gradual increase from childhood to adolescent years 8-12.
Consistent with prior studies8,9, our ICC and RC analysis demonstrate that the intraobserver and interobserver variability for 3DE LV volumes were good to excellent. Because the variability of LV EF in a normal population is small with a mean of 59.8±3.2%, the absolute reliability within observer and between observers were assessed using the RC analysis. LV EF intraobserver and interobserver reliability was also similar to previous studies evaluating for reproducibility of this measure.13-15
3DE LV EF has been reported to be more accurate and reproducible than 2DE LV EF in adults and children because 3DE does not rely on geometric assumptions and is less affected by 2D limitations such as foreshortening 3,16-20. These factors are apparent in LV with variable regional and global geometric shapes. Thus, similar to adult centers, 3DE LV volumes and EF should be reported in clinical centers with experience in 3DE 20. The z-scores generated by this multicenter study will serve as the normative data when evaluating pediatric patients with 3DE.