INTRODUCTION
Accurate and reproducible
measurements of cardiac chambers are a vital component of diagnosis,
prognostication, medical management, and surgical referral in congenital
as well as acquired heart diseases in children1,
2,3,4,5. Three-dimensional volumetric echocardiography (3DE) is an
emerging alternative to two-dimensional echocardiography (2DE) which
makes fewer geometric assumptions regarding chamber shapes and may
provide benefits in accuracy and reproducibility compared to
2DE6,7,8.
It is therefore important to establish that commercially available
algorithms for 3D measurement of cardiac chambers produce comparable
results. Both TomTec 4D LV-Analysis software and Philips QLAB LV 3D
underestimate LV volumes compared to MRI and have relatively wide
inter-vendor limits of agreement in neonates and
infants9. Although left atrial (LA) 3DE volumetric
analysis packages exist, most studies have used LV
packages6,7.
Knowledge-based reconstruction (KBR) is an alternative volumetric
methodology whereby 2DE images tracked in 3D space via a magnetic
localizer are reconstructed into a 3D dataset from which volumes can be
measured, thus overcoming the temporal and spatial resolution issues of
3DE. Ventripoint Medical Systems (VMS+ 3.0, (Ventripoint Diagnostics
Ltd., Toronto ON), utilizes a piecewise smooth subdivision surface
algorithm and an MRI-derived catalogue of heart datasets to reconstruct
a unique cardiac chamber rendering for each patient. VMS software
includes specific algorithms for all four cardiac chambers and has been
previously validated for right and left ventricular volume
measurements10,11,12. 3DE data and 3D MRI datasets can
also be imported into VMS3.0 for analysis, however no validation of the
resultant chamber volumes has been made against other 3DE analysis
software.
This study aimed to compare 3DE dataset derived LA and LV volumetric
measurement using VMS3.0 and TomTec 4D LV-analysis software. We
hypothesized that VMS would offer an alternative volumetric measurement
technique for cardiac chambers using a semi-automated software algorithm
with results comparable to TomTec.