Accuracy of left ventricular volumes and ejection fraction using high-intensity echo band as a landmark: Comparison between two-dimensional echocardiography and cardiac magnetic resonance imaging.

Background: The trace line for left ventricular (LV) volumes and ejection fraction (EF) measurements in 2-dimensional echocardiography (2DE) are often based on the empirical judgment of the examiner. We evaluated whether trace lines along the inner side of the high-intensity echo band that characterized LV endocardial boundary is useful for accurate measurements, with cardiac magnetic resonance (CMR) imaging as reference.

Methods: We compared the accuracy of LV volumes [end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV)] and EF in 73 patients, using CMR imaging as a reference. Protocol 1: 10 patients were compared by two examiners using the biplane disk summation method with trace line based on the empirical judgment of the examiner (before-learning) and trace line along the inner side of the high-intensity echo band (after-learning), and inter- and intra-observer variabilities were calculated. Protocol 2: the accuracy of LV volumes and EF was compared in 73 patients using the after-learning method. Bland-Altman analysis were used to compare with 2DE and CMR. The coefficient of variation was used for inter- and intra-observer variabilities.

Results: Protocol 1: For examiner 1, EDV (-16 ml vs 1 ml, p = 0.001), ESV (-9 ml vs 1 ml, p = 0.004), and SV (-7 ml vs 0 ml, p = 0.037) after learning compared with before learning were significantly approximated CMR measurements. For examiner 2, no significant differences were noted between before and after learning. The variability in measurements was smaller for all items by both examiners. Inter-observer variability after learning was improved compared with before learning, and intra-observer variability was also better. Protocol 2: LV volumes and EF measurements after learning were almost as accurate as CMR.

Conclusions: LV volumes and EF using after-learning trace approximated CMR measurements. Having landmark on trace line may contribute to quality control.