Left ventricular mass estimation by real-time 3D echocardiography favourably competes with CMR in congenital left ventricular disease.

Assessment of left ventricular mass (LVM) is important in the evaluation of patients with congenital heart disease (CHD) and cardiac magnetic resonance imaging (CMR) is the gold standard. Recent software allows LVM calculation by real-time 3-dimensional echocardiography (RT3DE). We investigated the impact of different software analysis tools on LVM determination by CMR or RT3DE in a cohort of patients with heterogeneous left ventricular (LV) disease. 37 subjects (17 patients, mean age 18.7 y; 20 controls, mean age 13.2 y) underwent CMR and RT3DE. CMR LVM and RT3DE calculations were done using two different LV-analysis software packages for each modality: CMR i) customized software "CMR HDZ", CMR ii) "CMR ISP"; RT3DE i) "Toshiba", RT3DE ii) "Tomtec", 4D LV-Analysis Version 3.1 (built 3.1.0.258661). Intra- and interobserver variabilities were calculated. Only RT3DE-derived LVM showed significant software-dependent differences. RT3DE-derived LVM (both softwares) was significantly higher than CMR-derived LVM (both softwares). The two different methods and four evaluation software packages for LVM assessment were well correlated with each other. Intra- and interobserver variability of LVM as assessed by each single modality or software was low. Despite software dependency and overestimation of RT3DE-assessed LVM by 5 to 10%, RT3DE still competes with the gold standard, CMR, even in patients with various forms of LV disease. The use of optimized software, especially for RT3DE, should improve the accuracy of LVM assessment, overcoming LVM overestimation.

Calculation of pediatric left ventricular mass: validation and reference values using real-time three-dimensional echocardiography.

BACKGROUND: Reference values for left ventricular mass (LVM) are important echocardiographic tools for the follow-up of pediatric patients with cardiac disease. Cardiac magnetic resonance (CMR) imaging is currently regarded as the gold standard. The aims of this study were to validate LVM calculated using real-time three-dimensional echocardiography (RT3DE) and to establish pediatric reference values. METHODS: For validation, 40 subjects (20 patients) consecutively underwent CMR (3-T TX Achieva, 25 cardiac phases/slice) and RT3DE (iE33 or Vivid E9, four subvolumes) in a single-center approach. The quantification of CMR data by the disk summation method as standard (mean LVM, 84.2 ± 53 g; range, 17.7-231.7 g) was compared with RT3DE. In a multicenter prospective design, 434 healthy children were investigated using standard software (LV-Analysis version 3.1). RESULTS: In comparison with CMR, RT3DE provided a slight overestimation of LVM of only 2.5 ± 11.3% (r = 0.990, intraclass correlation coefficient = 0.995), and there was low intraobserver (mean, 0.9 ± 7.1%; scatter, 13.2% to -15.0%; r = 0.996; intraclass correlation coefficient = 0.998) and interobserver (mean, 1.5 ± 9.3%; scatter, 17.2% to -20.1%; r = 0.993; intraclass correlation coefficient = 0.996) variability. Feasibility of the multicenter approach was 76%, resulting in 332 healthy children (median age, 10.0 years; range, 0-18 years; group I range, 0-6 years; group II range, 7-18 years) with data sets providing adequate image quality. LVM was correlated with sex (group II), age (r = 0.901), height (r = 0.881), weight (r = 0.876), and body surface area (r = 0.898). Unisex percentiles for 0 to 6 years of age and separated according to gender from 7 to 18 years of age were established. Mean calculation time for RT3DE was <3 min. CONCLUSIONS: In children, LVM calculation presuming excellent real-time three-dimensional echocardiographic data sets is accurate, quick, and reproducible. The percentiles provided are based on a large sample size and may be useful for clinical practice.

Knowledge-based reconstruction of right ventricular volumes using real-time three-dimensional echocardiographic as well as cardiac magnetic resonance images: comparison with a cardiac magnetic resonance standard.

BACKGROUND: Right ventricular volume quantification using real-time three-dimensional echocardiographic (RT3DE) imaging is limited by technical shortcomings of acquisition and quantification. In this study, a two-step approach was used to overcome these limitations. First, a modified acquisition technique for RT3DE imaging was applied, and second, a software tool using knowledge-based reconstruction (KBR) was used. The approach was validated against the gold standard, cardiac magnetic resonance (CMR) imaging, using CMR and RT3DE data sets from healthy children and from patients with congenital heart disease. METHODS: Sixty individuals (20 healthy persons, 40 with congenital heart defects; age range, 2.3-43.9 years; median age, 11.3 years) consecutively underwent investigation by CMR and RT3DE imaging. CMR data sets were first quantified by the method of disks (MOD) as the standard. Then CMR and RT3DE data sets were quantified using KBR software and compared with the MOD. RESULTS: CMR was more feasible than echocardiography (100% vs 88%). Compared with the MOD (CMRMOD), there were trivial volume overestimations of KBR for CMR data (CMRKBR), of end-diastolic volume (EDV) (-1.3 ± 8.6%, r = 0.984) and end-systolic volume (ESV) (-3.4 ± 13.3%, r = 0.985), resulting in a 0.7 ± 8.7% difference in ejection fraction (EF) (r = 0.882). Comparing CMRMOD and RT3DE imaging, EDV (1.1 ± 7.4%, r = 0.990) and EF (0.8 ± 9.2%, r = 0.871) were slightly underestimated by RT3DE imaging, with a slight overestimation of ESV (-1.5 ± 13.3%, r = 0.977). Intraobserver variability was excellent for KBR of CMR and RT3DE data, with interclass coefficients of correlation of 0.995 and 0.997 for EDV, 0.995 and 0.994 for ESV, and 0.915 and 0.912 for EF. Interobserver variability provided intraclass correlation coefficients of 0.992 and 0.990 for EDV, 0.997 and 0.992 for ESV, and 0.953 and 0.933 for EF. The KBR analysis required a mean time of 5 min. CONCLUSIONS: KBR is an accurate, versatile, and time-saving method for right ventricular three-dimensional volumetry; it shows excellent reproducibility for RT3DE and CMR data sets. These results suggest that this tool is clinically valuable.

Left ventricular volumetry in healthy children and adolescents: comparison of two different real-time three-dimensional matrix transducers with cardiovascular magnetic resonance.

AIMS: To assess the accuracy of different hardware and software settings for left ventricular (LV) volume quantification in children using real-time three-dimensional echocardiography (RT3DE). METHODS AND RESULTS: The impact of different matrix transducers (IE 33, X3-1 and VIVID 7, V3) and quantification software settings [TOMTEC; contour-finding activity (tCFA) values ranging from 30 to 70 U] on the accuracy of LV indices was tested in 24 healthy children/adolescents (median = 12.6 years) and 25 paediatric patients with Tetralogy-of-Fallot (TOF) (median = 7.3 years) with abnormally shaped ventricles. RT3DE was compared with cardiovascular magnetic resonance (CMR) volumetry as reference. Best agreement (Bland-Altman analysis) was achieved using a tCFA value of 30 U. Applying the V3 device, end-diastolic volume (EDV) and end-systolic volume (ESV) were underestimated by 14.8 +/- 10.6% (mean +/- SD) and 11.2 +/- 16.3%, respectively (r = 9.42, P < 0.001 and r = 0.937, P = 0.003); with the X3-1 system 24.2 +/- 11.0 and 14.6 +/- 15.2%, respectively (r = 0.951, P < 0.001 and r = 0.912, P = 0.001). Negligible differences <1% (P = n.s.) between both transducers were detected applying a tCFA value of 70 U but with significant underestimation (EDV: approximately 35%, P < 0.001; ESV: approximately 26%, P < 0.001) compared with CMR. EDV and ESV of TOF patients were underestimated by 3.2 +/- 15.4 and 8.1 +/- 22.6%, respectively. Intra- and interobserver variability was <4%. CONCLUSION: In contrast to recommendations of the manufacturer, data sets from both RT3DE transducers showed acceptable agreement to CMR for volumetric parameters only for low tCFA. Fine-tuning of software settings is mandatory to improve accuracy.