Relationship Between Image Quality and Bias in 3D Echocardiographic Measures: Data From the SABRE (Southall and Brent Revisited) Study

Background Image-quality (IQ) compromises left ventricle assessment by 3-dimensional echocardiography (3DE). Sicker/frailer patients often have suboptimal IQ, and therefore observed associations may be biased by IQ. We investigated its effect in an observational study of older people and when IQ was modified experimentally in healthy volunteers. Methods and Results 3DE feasibility by IQ was assessed in 1294 individuals who attended the second wave of the Southall and Brent Revisited study and was compared with 2-dimensional (2D)-echocardiography feasibility in 147 individuals. Upon successful analysis, means of ejection fraction (3D-EF) and global longitudinal strain (3D-GLS) (plus 2D-EF) were compared in individuals with poor versus good IQ. In 2 studies of healthy participants, 3DE-IQ was impaired by (1) intentionally poor echocardiographic technique, and (2) use of a sheet of ultrasound-attenuating material (neoprene rubber; 2-4 mm). The feasibility was 41% (529/1294) for 3DE versus 61% (89/147) for 2D-EF, P<0.0001. Among acceptable images (n=529), good IQ by the 2015 American Society of Echocardiography/European Association of Cardiovascular Imaging criteria was 33.6% (178/529) and 71.3% (377/529) for 3D-EF and 3D-GLS, respectively. Individuals with poor IQ had lower 3D-EF and 3D-GLS (absolute) than those with good IQ (3D-EF: 52.8±6.0% versus 55.7±5.7%, Mean-Δ -2.9 [-3.9, 1.8]; 3D-GLS: 18.6±3.2% versus 19.2±2.9%, Mean-Δ -0.6 [-1.1, 0.0]). In 2 experimental models of poor IQ (n=36 for both), mean differences were (-2.6 to -3.2) for 3D-EF and (-1.2 to -2.0) for 3D-GLS. Similar findings were found for other 3DE left ventricle volumes and strain parameters. Conclusions 3DE parameters have low feasibility and values are systematically lower in individuals with poor IQ. Although 3D-EF and 3D-GLS have potential advantages over conventional echocardiography, further technical improvements are required to improve the utility of 3DE in clinical practice.