Reproducibility of left ventricular measurements with acoustic quantification: The influence of training

Acoustic quantification (AO) of two-dimensional (2-D) echocardiograms provi des online estimation of left ventricular (LV) size and function. However, edge detection with AQ is influenced by gain settings and is therefore oper ator dependent. Our purpose was to compare AQ and conventional 2-D echo mea surements of LV size and function obtained by different operators and to ev aluate the influence of training on these measurements. A cardiac sonograph er without previous experience with the AQ system teas trained by an experi enced operator. Twenty-two normal males (age, 28 +/- 4 years) participated in the study. Images were recorded with conventional 2-D and AQ echo from t he short-axis and apical four-chamber views. During the initial training pe riod, five subjects were imaged by the sonographer under the supervision of the trainer. At the initial study session, 12 subjects were imaged indepen dently by the two operators. Following a second training period with five d ifferent subjects, the same initial 12 subjects were again imaged at a seco nd study session. LV cavity areas were traced from the conventional 2-D ech ocardiograms and measured from the AQ waveforms at end-diastole and end-sys tole. Volumes were calculated using the single-plane area-length method. Ej ection fraction (EF) was calculated from volumes. Reproducibility was deter mined by comparing the variability of AQ and conventional 2-D echo measurem ents obtained at the two sessions. A second training session reduced the op erator variability only of the short-axis end-diastolic area measurement (1 7 +/- 11% vs 6 +/- 5%, P < 0.025). We conclude that a single training sessi on may be adequate for the reproducible estimation of ventricular volumes w ith the AQ method.