Robustness of a new three-dimensional echocardiographic algorithm for left ventricular volume and ejection fraction quantification: experts vs. novices

Abstract

We evaluated the ability of a new simplified algorithm for three-dimensional echocardiography (3DE) left ventricular (LV) measurements with minimal operator interaction to be reproducible and robust, independently of the experience. A total of 163 subjects were investigated using two-dimensional echocardiography (2DE) and 3DE. The 3D data sets were blindly analysed offline by novice investigators and experts. A subgroup of 30 patients was assessed using cardiac magnetic resonance imaging (CMRI) to compare end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) obtained by 2DE, 3DE, and CMRI. Intra-observer and inter-observer variabilities of 2DE and 3DE measurements were evaluated according to level of experience. Mean time analysis of 3DE data was 23.2 ± 6.3s for the novice and 26.1 ± 4.1 s for the expert (P = ns). Correlations (r) and mean error measurements (MEM) between 3DE analysis by experts and novices were 0.91 and -3.5 mL for EDV, 0.97 and 4.3 mL for ESV, and 0.91 and -2.6% for EF, respectively. Correlations between 3DE and CMRI were good with low variability and greater agreement when compared with those between 2DE and CMRI. For the novice, MEM was -21.3 mL for EDV, -15.0 mL for ESV, and 2.3% for EF. MEM and 95% confidence intervals were wider for 2DE vs. CMRI than for 3DE vs. CMRI in relation to both expert and novice. This new semi-automated algorithm of LV endocardial border detection based on 3DE data appears suitable for clinical use by either expert or novice investigators with greater reproducibility and time of analysis than 2DE.