Objectives: Quick and accurate functional assessment of the left ventricle (LV) is essential to evaluate young patients with congenital heart disease (CHD). In comparison to the gold standard cardiac magnetic resonance (CMR) real-time three-dimensional echocardiography (RT3DE) is getting more precise, is quick, cost-efficient and convenient especially in very young patients. As there are differences in quantification strategy between quantification softwares, validation should precede the calculation of reference values.
Methods: A cohort of 39 subjects (n = 17 healthy children and n = 22 patients with CHD) consecutively underwent CMR (3-T TX Achieva, 25 cardiac phases/slice) and RT3DE (IE 33, Vivid E9, four subvolumes). After quantification of end-diastolic and end-systolic volumes (EDV, ESV) using dedicated software (CMR: HDZ MR-Tools, RT3DE: 4D LV-Analysis 3.1 software [Tomtec]), results were compared using Bland-Altman statistics. In a multicenter design 376 RT3DE datasets of healthy children (188 females) were analyzed for generation of centiles.
Results: LV volumes, both EDV (EDV: 17 ± 14%, LOA (limits of agreement): −11 to 45%, r = 0.96) and ESV (ESV: 14.8 ± 23.7%, LOA −32.5 to 62.1%, r = 0.913), showed a slight but significant underestimation by RT3DE in comparison to CMR resulting in excellent agreement of ejection fraction (EF: 0.5 ± 10.7%, LOA: −20.9 to 21.8). Reproducibility was promising (intraobserver variability: EDV: 2.5 ± 10.1%, LOA: −17.7 to 22.8%, ICC [intraclass correlation coefficient] 0.959, ESV: −0.3 ± 13.4%, LOA: −27.2 to 26.6%, ICC 0.939, interobserver variability: EDV: 1.1 ± 11.5%, LOA: −21.8 to 24%, ICC 0.946, ESV: −2.1 ± 19%, LOA: −40 to 35.9%, ICC: 0.862). Quality of datasets and intensive interoperator training for RT3DE analysis was necessary to obtain this accuracy of the analyses. Mean calculation time was 5 minutes.
Conclusion: RT3DE offers quick and accurate evaluation of LV volumes with slight underestimation of volumes and is therefore appropriate for the investigation of patients with CHD. The centile curves provide a helpful tool in the clinical context of follow-up studies in the maturating heart.
