Sources of variation and bias in assessing left ventricular volumes and dyssynchrony using three-dimensional echocardiography

Study aim To explore various sources of variability in the measurement of LV volumes and dyssynchrony by 3D echocardiography (3DE). Methods We studied 100 patients (58 ± 18 years, 51 men) to assess the impact of: (1) manual editing; (2) 3D data set temporal resolution; (3) LV 16- or 17-segmentation model; (4) software sensitivity for automated endocardial surface detection; and (5) image quality, on the measurement of LV end-diastolic (EDV) and end-systolic (ESV) volumes, sphericity indices (EDSI, ESSI), ejection fraction (EF) and dyssynchrony (SDI). Two- and 4-beat LV full-volume data sets were analyzed and compared. Cardiac magnetic resonance (CMR) was used as reference in 26 patients. Results Manual editing of endocardial surface improved the agreement of LV volumes with CMR, but increased SDI (SDI17: 5.6 ± 0.5% vs. 4.3 ± 0.3%; P < 0.0001). Data set temporal resolution had no significant impact on LV parameters. Adding the 17th to 16-segment LV model did not significantly increase SDI. Reducing software sensitivity in endocardial surface detection increased EDV (101 ± 46 ml vs. 118 ± 50 ml) and sphericity, decreased SDI (SDI 17: 6.7 ± 3.3% vs. 2.9 ± 3.7%) (P < 0.05 for all), and improved agreement of EDV and ESV with CMR. Impact of software sensitivity in LV endocardium detection on LV parameters was related to image quality: higher on SDI in pts with suboptimal quality (SDI 17 bias 4.5% vs. 3.2%, P < 0.05); higher on LV volumes in patients with optimal quality (EDV bias 14 ml vs. 19 ml, ESV bias 5 ml vs. 9 ml; P = 0.01). Conclusions Manual editing, software settings and image quality significantly impact on 3D LV volumes and dyssynchrony assessment.