Abstract Introduction We hypothesised that real-time three-dimensional echocardiography (RT-3DE) was superior to bi-dimensional (2D) echocardiography for the estimation of left atrial volume (LAV), using electrocardiographic (ECG)-gated multidetector computed tomography angiography (MDCTA) as a volumetric gold standard. The aim was to compare maximum LAV (LAVmax) and minimum LAV (LAVmin) measured by biplane area-length method (ALM), biplane method of disk (MOD) and RT-3DE with 64-slice ECG-gated MDCTA in dogs. Animals Twenty dogs, anaesthetised for various diagnostic purposes and without evidence of cardiovascular disease. Methods Left atrial volume was estimated by ALM, MOD and RT-3DE following ECG-gated MDCTA. The results were compared with LAV from MDCTA and correlations were performed. The limits of agreement (LoA) between methods were evaluated using Bland-Altman analysis and intra class correlations. Coefficients of variation were calculated. Results Area-length method (r = 0.79 and 0.72), MOD (r = 0.81 and 0.70) and RT-3DE (r = 0.94 and 0.82) correlated with MDCTA for LAVmax and LAVmin respectively (all p<0.05). Biases for LAVmax (-0.96 mL, 95% LoA: -5.6 – 3.7) and LAVmin (-0.67 mL, 95% LoA: -5.4 – 4.1) were minimal with RT-3DE, reflecting a slight underestimation. Conversely, MOD (LAVmaxbias = 3.19 mL, 95% LoA: -5.7 – 12.1; LAVminbias = 1.96 mL, 95% LoA: -4.6 – 8.5) and ALM (LAVmaxbias = 4.05, 95% LoA: -5.7 – 13.8; LAVminbias = 2.80 mL, 95% LoA: -3.9 – 9.5) suggested LAV overestimation. Intra- and inter-observer variability were adequate. Conclusions Real-time three-dimensional echocardiography is a non-invasive, accurate and feasible method with superior accuracy to 2D methods.
- cardiac volumes
- biplane modified Simpson method
- biplane area-length method
- advanced cardiac imaging