Left atrial volumes assessed by three- and two-dimensional echocardiography compared to MRI estimates.
OBJECTIVE
The aim of the present study was to establish the accuracy and reproducibility of left atrial volume measurements by three-dimensional (3D) echocardiography compared to 2D biplane and monoplane measurements.


BACKGROUND
No echocardiographic technique is generally accepted as optimal for estimation of left atrial size.


METHODS
Left atrial volumes of 18 unselected cardiac patients were obtained with magnetic resonance imaging (MRI) (volumes 145 +/- 58 ml). These volumes were compared with those obtained with different echocardiographic methods: a multiplane 3D method based on 90 images acquired by apical probe rotation, a simplified 3D method using only the three standard apical views, and 2D biplane and monoplane methods based on area-length, disc summation and spherical formulas.


RESULTS
The echocardiographic methods significantly underestimated maximum left atrial volumes as obtained by MRI by 14-37% (p < 0.001). Accuracy, expressed as 1 SD of individual estimates around this systematic underestimation, was 25 to 27% for all methods, except for the 2D 2-chamber monoplane method (37%). Interobserver coefficient of variation was between 14 and 20% for all methods (n.s.).


CONCLUSIONS
All echocardiographic methods significantly underestimated left atrial volumes as obtained by MRI. A minor non-significant improvement in individual echocardiographic estimates by the 3D methods was obtained at the cost of more time consumption. In unselected patients ultrasound image quality precludes significant improvement of left atrial volume measurements by the applied 3D methods.
Rodevan
O
O
Department of Cardiology, The National Hospital-Rikshospitalet, University of Oslo, Norway.
Bjornerheim
R
R
Ljosland
M
M
Maehle
J
J
Smith
H J
HJ
Ihlen
H
H
D000368:Aged; D002306:Cardiac Volume; D019560:Echocardiography, Three-Dimensional; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results