Real-time 3D-echocardiography of the right ventricle—paediatric reference values for right ventricular volumes using knowledge-based reconstruction: a multicentre study

BACKGROUND: Real-time 3D echocardiography is a promising method for non-invasive assessment of right ventricular performance in children with congenital heart disease. Volume quantification using knowledge-based reconstruction (KBR) enables the calculation of right ventricular dimensions by matching endocardial landmarks with a reference library of right ventricular shapes. However, paediatric reference values for volumes based on KBR are missing. Aim of this study was to establish reference values for right ventricular volumes in a large paediatric population using 3D echocardiography and KBR. METHODS: In a multicentre prospective-design study, 545 healthy children and adolescents (age range, 1 day to 216 months) underwent 3D echocardiography of the right ventricle using two different vendors (iE33, Philips or Vivid 7, GE). Volume analysis was performed by a semiautomatic quantification software (VMS, Ventripoint Diagnostics Ltd., Washington, US). Reference centiles were computed using Cole's LMS method and the gamlss package in R. For vendor comparison, 3D datasets were recorded subsequently in 20 subjects using both ultrasound devices. RESULTS: 3D datasets of 406/545 (74.5%) subjects provided an adequate image quality. Right ventricular volumes had a significant association with age, body size and sex. We created sex-specific percentiles indexed to body surface area (BSA). Intra- and interobserver-variation for all volume calculations were excellent with intraclass correlation coefficients (ICCs) between 0.973-0.998. Agreement of both vendors showed slightly higher end-diastolic and stroke volumes (bias ± standard deviation 2.2%±6.8% respectively 4.5%±8.1%) and smaller end-systolic volumes (-0.9±10.3%) using Philips datasets. CONCLUSIONS: Calculation of ventricular volumes by KBR allows reliable non-invasive assessment of right ventricular volumes with excellent intra- and interobserver variations. The calculated percentiles based on a large paediatric population serve as a reference and may facilitate the use of real-time 3D echocardiography for the analysis of right ventricular size and function.