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.