A multicenter study of three-dimensional echocardiographic evaluation of normal pediatric left ventricular volumes and function

Size and Function of the Right Atrium in Healthy Children by Three-Dimensional Echocardiography

PURPOSE

Right atrial volume (RAV) and function have proven prognostic value in the assessment of cardiac disease and may be more accurately assessed using three-dimensional echocardiography (3DE). Normal 3DE reference values for the right atrial (RA) volume and function in healthy children have not yet been published. Furthermore, current methods of indexing cardiac measurements to body surface area (BSA) alone may be insufficient. We aimed to develop reference values for 3DE-derived RAV and function in the pediatric population, to provide a comparison of regression methods using BSA, height, weight, and sex, and to compare 3DE values to two-dimensional echocardiography (2DE) derived volumes.

METHODS

We retrospectively analyzed 187 3DE datasets acquired for a multi-center study on healthy children at two international centers. 3DE volumes were measured with vendor-agnostic software (Tomtec), and 2DE endo-diastolic volume (EDV) using the area-length single-plane approach. Regression curve-fitting of height (Ht), weight (Wt), BSA, and sex were explored to optimize Pearson coefficient and homoscedasticity.

RESULTS

The relationship of 3DE RAVs to BSA alone was heteroscedastic, with a residual positive relationship on indexing (R2 = 0.2506). Optimal regression of Ln (Volume) = b0 + x*Ln (Ht) + y*Ln (Wt) + z*Sex was homoscedastic. Total RA emptying fraction (EF) did not vary across age or sex, however active and passive emptying was best fit by a spline curve with a knot at approximately BSA = 1 m2. Strong agreement with 2DE-derived EDV was present (r2 = 0.83).

CONCLUSION

We provide reference values for RA size and function in the pediatric population and provide a comparison of methods for indexing these values.

Comparing a knowledge-based 3D reconstruction algorithm to TomTec 3D echocardiogram algorithm in measuring left cardiac chamber volumes in the pediatric population

BACKGROUND

Three-dimensional echocardiography (3DE) is an emerging method for volumetric cardiac measurements; however, few vendor-neutral analysis packages exist. Ventripoint Medical System Plus (VMS3.0+) proprietary software utilizes a validated Magnetic resonance imaging (MRI) database of normal ventricular and atrial morphologies to calculate chamber volumes. This study aimed to compare left ventricular (LV) and atrial (LA) volumes obtained using VMS3.0+ to Tomtec echocardiography analysis software.

METHODS

Healthy controls (n = 98) aged 0-18 years were prospectively recruited and 3D DICOM datasets focused on the LV and LA acquired. LV and LA volumes and ejection fractions were measured using TomTec Image Arena 3D LV analysis package and using VMS3.0+. Pearson correlation coefficients, Bland-Altman's plots, and intraclass coefficients (ICC) were calculated, along with analysis time.

RESULTS

There was a very good correlation between Ventripoint Medical System (VMS) and Tomtec LV systolic (r²  = .88, ICC .89 [95% CI .81, .94]), and diastolic (r²  = .88, ICC .90 [95% CI .77, .95]) volumes, and between VMS and Tomtec LA diastolic (r²  = .75, ICC .89 [95% CI .81, .93]) and systolic (r²  = .88, ICC .91 [95% CI .78, .96]) volumes on linear regression models. Natural log transformations eliminated heteroscedasticity, and power transformations provided the best fit. The time (mins) to analyze volumes using VMS were less than using Tomtec (LV VMS 2.3 ± .5, Tomtec 3.3 ± .8, p < .001; LA: VMS 1.9 ± .4, Tomtec 3.4 ± 1.0, p < .001).

CONCLUSIONS

There was a very good correlation between knowledge-based (VMS3.0+) and 3D (Tomtec) algorithms when measuring 3D echocardiography-derived LA and LV volumes in pediatric patients. VMS was slightly faster than Tomtec in analyzing volumetric measurements.