Quantification of left ventricular volumes and ejection fraction using freehand transthoracic three-dimensional echocardiography: comparison with magnetic resonance imaging.
OBJECTIVE
Our aim was to validate 3-dimensional echocardiography (3DE) for assessment of left ventricular (LV) end-diastolic volume, end-systolic volume (ESV), stroke volume, and ejection fraction (EF) using the freehand-acquisition method. Furthermore, LV volumes by breath hold-versus free breathing-3DE acquisition were assessed and compared with magnetic resonance imaging (MRI).


METHODS
From the apical position, a fan-like 3DE image was acquired during free breathing and another, thereafter, during breath hold. In 27 patients, 28 breath hold- and 24 free breathing-3DE images were acquired. A total of 17 patients underwent both MRI and 3DE. MRI contours were traced along the outer endocardial contour, including trabeculae, and along the inner endocardial contour, excluding trabeculae, from the LV volume.


RESULTS
All 28 (100%) breath hold- and 86% of free breathing-3DE acquisitions could be analyzed. Intraobserver variation (percentual bias +/- 2 SD) of end-diastolic volume, ESV, stroke volume, and EF for breath-hold 3DE was, respectively, 0.3 +/- 10.2%, 0.3 +/- 14.6%, 0.1 +/- 18.4%, and -0.1 +/- 5.8%. For free-breathing 3DE, findings were similar. A significantly better interobserver variability, however, was observed for breath-hold 3DE for ESV and EF. Comparison of breath-hold 3DE with MRI inner contour showed for end-diastolic volume, ESV, stroke volume, and EF, a percentual bias (+/- 2 SD) of, respectively, -13.5 +/- 26.9%, -17.7 +/- 47.8%, -10.6 +/- 43.6%, and -1.8 +/- 11.6%. Compared with the MRI outer contour, a significantly greater difference was observed, except for EF.


CONCLUSIONS
3DE using the freehand method is fast and highly reproducible for (serial) LV volume and EF measurement, and, hence, ideally suited for clinical decision making and trials. Breath-hold 3DE is superior to free-breathing 3DE regarding image quality and reproducibility. Compared with MRI, 3DE underestimates LV volumes, but not EF, which is mainly explained by differences in endocardial contour tracing by MRI (outer contour) and 3DE (inner contour) of the trabecularized endocardium. Underestimation is reduced when breath-hold 3DE is compared with inner contour analysis of the MRI dataset.
Mannaerts
Herman F J
HF
Department of Cardiology and Institute for Cardiovascular Research, VU University Medical Center., Amsterdam, The Netherlands. hfj.mannaerts@vumc.nl
Van Der Heide
Johannes A
JA
Kamp
Otto
O
Papavassiliu
Theano
T
Marcus
Johannes T
JT
Beek
Aernout
A
Van Rossum
Albert C
AC
Twisk
Jos
J
Visser
Cees A
CA
D000368:Aged; D019560:Echocardiography, Three-Dimensional; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D016277:Ventricular Function, Left