Assessment of left atrial volume in dogs: comparisons of two-dimensional and real-time three-dimensional echocardiography with ECG-gated multidetector computed tomography angiography

Abstract

IntroductionWe hypothesized that real-time three-dimensional echocardiography (RT-3DE) was superior to two-dimensional 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 AnimalsThe study included twenty dogs, anaesthetized for various diagnostic purposes and without evidence of cardiovascular disease. MethodsLeft 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 intraclass correlations. Coefficients of variation were calculated. ResultsArea-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 to 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. Intraobserver and interobserver variability were adequate. ConclusionsReal-time three-dimensional echocardiography is a non-invasive, accurate and feasible method with superior accuracy to two-dimensional methods.