Paraplane analysis from precordial three-dimensional echocardiographic data sets for rapid and accurate quantification of left ventricular volume and function: a comparison with magnetic resonance imaging

Three-dimensional echocardiography (3DE) calculates left ventricular volumes (LVV) and ejection fraction (EF) without geometric assumptions, but prolonged analysis time limits its routine use. This study was designed to validate a modified 3DE method for rapid and accurate LVV and EF calculation compared with magnetic resonance imaging (MRI). Forty subjects included 15 normal volunteers (group A) and 25 patients with segmental wall motion abnormalities and global hypokinesis caused by ischemic heart disease (group B) who underwent 3DE with precordial rotational acquisition technique (2-degree interval with electrocardiographic and respiratory gating) and MRI at 0.5 T, electrocardiogram (ECG)-triggered multislice multiphase T1-weighted fast field echo. End-diastolic and end-systolic LVV and EF were calculated from both techniques with Simpson's rule by manual endocardial tracing of equidistant parallel left ventricular short-axis slices. Slicing from the 3DE data sets were done by both 2.9-mm slice thickness (method 3DE-A) and by 8 equidistant short-axis slices (method 3DE-B); for MRI analysis, 9-mm slice thickness was used. Analysis time required for manual endocardial tracing of end-diastolic and end-systolic short-axis slices was 10 minutes for the 3DE-B method compared with 40 minutes by the 3DE-A method. For all 40 subjects the mean +/- SD of end-diastolic LVV (mL) were 181 +/- 76, 179 +/- 73, and 182 +/- 76; for end-systolic LVV (mL), 120 +/- 76, 120 +/- 75, and 122 +/- 77; and for EF (%), 39 +/- 18, 38 +/- 18, and 38 +/- 18 for MRI, 3DE-A, and 3DE-B methods, respectively. The differences between 3DE-A and 3DE-B with MRI for calculating end-diastolic and end-systolic LVV and EF were not significant for the whole group of subjects as well as for the subgroups. The 3DE-B method had excellent correlation and close limits of agreement with MRI for calculating end-diastolic and end-systolic LVV and EF: r = 0.98 (-1.3 +/- 26.6), 0.99 (-1.6 +/- 21. 2), and 0.99 (0.2 +/- 5.2), respectively. The correlation between 3DE-A and MRI were r = 0.97, 0.98, and 0.98, and the limits of agreement were -1.4 +/- 36, -0.6 +/- 26, and 0.6 +/- 8 for calculating end-diastolic and end-systolic LVV and EF, respectively. In addition, excellent correlation and close limits of agreement between 3DE-A and 3DE-B with MRI for LVV and EF calculation was also found for the subgroups. Intraobserver and interobserver variability (SEE) of MRI for calculating end-diastolic and end-systolic LVV and EF were 6.3, 4.7, and 2.1; and 13.6, 11.5, and 4.7; respectively, whereas that for 3DE-B were 3.1, 4.4, and 2.2; and 6.2, 3.8, and 3. 6; respectively. Comparable observer variability was also found for the A and B subgroups. The 3DE-A and 3DE-B methods have excellent correlation and close limits of agreement with MRI for calculating LVV and EF in both normal subjects and cardiac patients. The 3DE-B method by paraplane analysis with 8 equidistant short-axis slices has observer variability similar to MRI and reduces the 3DE analysis time to 10 minutes, therefore offering a rapid, reproducible, and accurate method for LVV and EF calculatio

Measurements and day-to-day variabilities of left ventricular volumes and ejection fraction by three-dimensional echocardiography and comparison with magnetic resonance imaging

The aim of this study was to assess day-to-day variability of left ventricular (LV) volume and ejection fraction (EF) calculated from 3-dimensional echocardiography (3-DE) and to compare the reproducibility of the measurement with magnetic resonance imaging. Forty-six subjects were examined including 15 normal volunteers (group A) and 31 patients with LV dysfunction (group B). Precordial 3-DE acquisition was performed at 2 degrees rotational intervals and repeated 1 week later. Magnetic resonance imaging was performed at 0.5 T. End-diastolic and end-systolic LV volumes were derived using Simpson's rule by manual endocardial tracing of 8 equidistant parallel LV short-axis slices with 3-DE, whereas 9-mm slices were used with magnetic resonance imaging. The mean +/- SD of end-diastolic and end-systolic LV volumes (ml) and EF (%) from magnetic resonance imaging were 182 +/- 75, 121 +/- 76, and 39 +/- 18, whereas those from 3-DE were 182 +/- 76, 121 +/- 77, and 39 +/- 18 respectively. Day-to-day measurements of end-diastolic and end-systolic LV volumes, and EF on 3-DE were not significantly different as assessed with SEE (2.7, 1.1, and 2.4, respectively). Intra- and interobserver SEE for calculating end-diastolic and end-systolic LV volumes and EF for magnetic resonance imaging were 6.3, 4.7, and 2.1 and 13.6, 11.5, and 4.7, respectively, whereas those for 3-DE were 3.1, 4.4, and 2.2 and 6.2, 3.8, and 3.6, respectively. Day-to-day variability of LV volume and EF calculation on 3-DE were small and not significantly different for normal and dysfunctional left ventricles. Observer variabilities of 3-DE were fewer than those of magnetic resonance imaging. Therefore, 3-DE is recommended for serial assessment of LV volume and EF in normal and abnormally shaped ventricle

Optimal rotational interval for 3-dimensional echocardiography data acquisition for rapid and accurate measurement of left ventricular function

Prolonged 3-dimensional echocardiography (3DE) acquisition time currently limits its routine use for calculating left ventricular volume (LVV) and ejection fraction (EF). Our goal was to reduce the acquisition time by defining the largest rotational acquisition interval that still allows 3DE reconstruction for accurate and reproducible LVV and EF calculation. Twenty-one subjects underwent magnetic resonance imaging and precordial 3DE with 2 degrees acquisition intervals. Images were processed to result in data sets containing images at 2 degrees, 4 degrees, 8 degrees, 16 degrees, 32 degrees, and 64 degrees intervals by excluding images in between. With use of the paraplane feature, 8 equidistant short-axis slices were generated from each data set. The suitability of these short-axis slices for manual endocardial tracing was scored visually by 4 independent experienced observers. The LVV and EF were calculated by using Simpson's rule from 3DE data sets with 2 degrees, 8 degrees, and 16 degrees intervals, and the results were compared with values obtained from magnetic resonance imaging. The probability of 3DE to detect LVV and EF differences was calculated. All patients were in sinus rhythm with a mean heart rate of 72 bpm (SD + or - 12). The LV short-axis images obtained with 16 degrees rotational scanning intervals allowed LV endocardial tracing in all subjects. Good correlation, close limits of agreement, and nonsignificant differences were found between values of LVV and EF calculated with 3DE at 2 degrees, 8 degrees, and 16 degrees rotational intervals and those obtained with magnetic resonance imaging. At steps of 16 degrees, 3DE had excellent correlation (r = 98, 99, and 99), close limits of agreement (+ or - 38, + or - 28.6, and + or - 4.8), and nonsignificant differences (P =.5,.8, and.2) with values obtained from magnetic resonance imaging for calculating end-diastolic LVV, end-systolic LVV, and EF, respectively. Three-dimensional echocardiography with use of 16 degrees rotational intervals could detect 15-mL differences in end-diastolic volume with a probability of 95%, 11-mL differences in end-systolic volume with a probability of 92%, and 0.02 differences in EF with a probability of 95%. The 3DE data sets reconstructed with images selected at 16 degrees intervals from data sets obtained at 2 degrees precordial rotational acquisition intervals allowed the generation of LV short-axis images with adequate quality for endocardial border tracing. Therefore precordial acquisition at 16 degrees intervals would be sufficient for the reconstruction of 3DE data sets for LV function measurement. This would reduce the acquisition time while maintaining enough accuracy for clinical decision making and would thus make 3DE more practical as a routine metho