Accuracy and reproducibility of quantitation of left ventricular function by real-time three-dimensional echocardiography versus cardiac magnetic resonance

The aim of this study was to investigate the accuracy and reproducibility of the quantification of left ventricular (LV) function by real-time 3-dimensional echocardiography (RT3DE) using current state-of-the-art hardware and software. Compared with cardiac magnetic resonance (CMR), previous generations of hardware and software for RT3DE significantly underestimated LV volumes partly because of inherent factors such as limited spatial and temporal resolution. Also, RT3DE volumes were compared with short-axis CMR data, whereas a combined short-axis and long-axis analysis is known to be superior. Twenty-four subjects (mean age 51 +/- 12 years, 17 men) in sinus rhythm and with good to excellent 2-dimensional image quality underwent RT3DE and CMR within 1 day. The acquisition of RT3DE data was done with current state-of-the-art hardware and software. Two blinded experts performed off-line LV volume analysis. Global LV volumes were determined from semiautomated border detection on the basis of endocardial speckle tracking with biplane projections using QLAB version 6.0. Volumes derived by magnetic resonance imaging were quantified from combined short-axis and long-axis series. The volume-rate on RT3DE was 33 +/- 8 Hz (range 19 to 42). Excellent correlations were found (R(2) >/= 0.97) between CMR and RT3DE for global LV end-diastolic volume, LV end-systolic volume, the LV ejection fraction, and LV phase volumes (24 phases/cardiac cycle). Bland-Altman analyses showed mean differences of -7.1 ml, -4.2 ml, 0.2%, and -5.8 ml and 95% limits of agreement of +/-19.7 ml, +/-8.3 ml, +/-6.2%, and +/-15.4 ml for global LV end-diastolic volume, LV end-systolic volume, the LV ejection fraction, and LV phase volumes, respectively. Interobserver variability was 5.2% for global LV end-diastolic volume, 6.4% for LV end-systolic volume, and 7.6% for the LV ejection fraction. In conclusion, in patients with good acoustic windows, RT3DE using state-of-the-art technology provides accurate and reproducible measurements of global LV volumes, LV volume changes over time, and the LV ejection fraction.     

Evaluation of left ventricular volumes measured by magnetic resonance imaging

Left ventricular end-diastolic and end-systolic volumes were determined in 17 patients with different levels of left ventricular function by magnetic resonance imaging (MRI). A 1.5 Tesla Magnet was used obtaining ECG triggered single and multiple slices. Calculated cardiac outputs were compared with those measured simultaneously by a classical physiological indicator dilution technique. There was good agreement between cardiac output as measured by MRI and the indicator dilution method, when the multislice technique was used (r = 0.87, p less than 0.001). A poor correlation between the two methods was seen when the single slice technique was used (r = 0.06, p greater than 0.80). The results indicate that MRI is a reliable method for left ventricular volume determination when the multislice technique is used.     

Comparison of accurate measurement of left ventricular mass in patients with hypertrophied hearts by real-time three-dimensional echocardiography versus magnetic resonance imaging

To evaluate whether left ventricular (LV) mass assessed by a new real-time, 3-dimensional echocardiographic (RT-3DE) system corresponds to cardiac magnetic resonance imaging (MRI) in patients with LV hypertrophy, RT-3DE and 2-dimensional echocardiography (2DE) were performed to calculate LV mass in 21 patients (mean age 54 +/- 15 years) who underwent MRI for the evaluation of LV hypertrophy. In 20 of 21 patients, adequate 3-dimensional data for LV mass analysis were obtained, and regression analysis showed that LV mass by RT-3DE correlated with that determined by MRI (r = 0.95, y = 28.9 + 0.85x) better than with that determined by 2DE (r = 0.70, y = 43.6 + 0.81x). RT-3DE allows the accurate measurement of LV mass in patients with hypertrophied hearts.     

Quantitation of right ventricular volumes and ejection fraction by three-dimensional echocardiography in patients: comparison with magnetic resonance imaging and radionuclide ventriculography

Three-dimensional echocardiography (3DE) provides volumetric measurements without geometric assumptions. Volume-rendered 3DE has been shown to be accurate for the measurement of right ventricular (RV) volumes in vitro and in animal studies; however, few data are available regarding its accuracy in patients. This study examined the accuracy of 3DE for quantitation of RV volumes and ejection fraction (EF) in patients, compared to magnetic resonance imaging (MRI) and radionuclide ventriculography (RNV). Twenty patients underwent MRI, gated equilibrium RNV, and 3DE using rotational acquisition from both the transesophageal and transthoracic approaches. RV volumes and EF were calculated from the 3DE data using multislice analysis (true Simpson's rule). RV volumes calculated by MRI (end-diastolic volume (EDV) 109.4 +/- 34.3 mls, end-systolic volume (ESV) 59.6 +/- 31.0 mls, and EF 47.7 +/- 17.1%) agreed closely with 3DE. For transesophageal echocardiography, EDV was 108.1 +/- 29.7 mls (r = 0.86, mean difference 1.3 +/- 17.8 mls); ESV was 62.5 +/- 23.8 mls (r = 0.85, mean difference 2.8 +/- 15.1 mls); and EF was 43.2 +/- 11.7% (r = 0.84, mean difference 4.5 +/- 9.7%). For transthoracic echocardiography, EDV was 107.7 +/- 27.5 mls (r = 0.85, mean difference 1.6 +/- 18.2 mls); ESV was 59.7 +/- 22.1 mls (r = 0.93, mean difference 3.2 +/- 19.6 mls); and EF was 45.2 +/- 11.5% (r = 0.86, mean difference 2.0 +/- 9.4%). There were close correlations, small mean differences and narrow limits of agreement between RNV-derived EF (43.4 +/- 12.1%) and both transesophageal (r = 0.95 mean difference 0.2 +/- 3.7%) and transthoracic 3DE (r = 0.95, mean difference 1.8 +/- 5.4%). Three-dimensional echocardiography is a promising new method of calculating RV volumes and EF, comparing well with MRI and RNV. The accuracy of transthoracic 3DE was comparable to that of the transesophageal approach. Three-dimensional echocardiography has the potential to be useful in the clinical assessment of RV disorders.     

Right ventricular volumes and ejection fraction estimated by two-dimensional echocardiography

The right ventricular volumes and ejection fraction (RVEF) obtained from two-dimensional echocardiography and from right ventricular angiography were compared in 20 patients with congenital heart disease. Single plane area-length method of apical four-chamber view was used to estimate echocardiographic right ventricular volumes and single plane right anterior oblique projection was used to calculate angiographic right ventricular volumes. The results showed that right ventricular volumes estimated by echocardiography correlated highly with that calculated by angiography, the correlation coefficients of end-diastolic volume, end-systolic volume and stroke volume were 0.983, 0.976, 0.973 respectively. Echocardiographic RVEF also correlated strongly with angiographic RVEF (r = 0.992, P less than 0.001), and there were no significant difference between the two methods (P greater than 0.05). Conclusion: two-dimensional echocardiography can be used to accurately estimate right ventricular volumes and ejection fraction.     

Determination of left ventricular volumes and ejection fraction by nuclear magnetic resonance imaging

To determine the ability of nuclear magnetic resonance (NMR) imaging to assess left ventricular (LV) volumes and ejection fraction (EF), we studied 24 patients within 48 hours of single-plane LV angiography. In all patients, a transverse, single-plane NMR acquisition technique was employed with LV end-diastolic (ED) and end-systolic (ES) volumes (V) calculated by a modified area-length algorithm. In nine patients, a multislice acquisition technique was employed with LVEDV and LVESV calculated by a Simpson's rule algorithm. NMR-determined LVV and EF correlated reasonably well with angiographic values (LVEDV: r = 0.75; LVESV: r = 0.90; and LVEF: r = 0.76). The single-plane NMR technique significantly underestimated LVEDV (p less than 0.01), whereas no significant difference was demonstrated for LVESV. As a result, angiographic LVEF was significantly underestimated (p less than 0.05). This underestimation is likely related to off-axis imaging and to the geometric constraints of a single-plane algorithm. In comparing multislice NMR to angiographic data, no significant difference was demonstrated for LVEDV, LVESV, or LVEF. Thus, quantitation of LVV and EF with NMR is feasible, and comparison to angiographic volumes is similar to results reported from other noninvasive imaging modalities. Improvement in current acquisition techniques and software should result in further quantitative potential.     

Unbiased and efficient estimation of left ventricular volumes by three-dimensional echocardiography with coaxial sections. Validation with magnetic resonance imaging

The objective of this study was to investigate the degree of bias with coaxial three-dimensional echocardiography in an experimental animal setup and to establish the minimum number of sections needed for estimation of left ventricular (LV) volume. Epicardial coaxial echocardiography and magnetic resonance imaging (MRI) was used to measure LV volume in 14 pigs, with chronic remodeled left ventricles induced by repeated intracoronary microembolizations. In addition, six animals underwent serial MRI at baseline, immediately after intracoronary microembolization, and after 119–165 days (mean 129 days). Coaxial echocardiography was performed by rotational acquisition of long-axis sections starting from an arbitrary angle. Planimetered MRI contours of LV endocardial borders were analyzed to investigate the relationship between the number of coaxial sections, and the precision of volume estimates. The mean ± 2SD of the differences between coaxial epicardial echocardiography with six sections and MRI were −2.5 ± 16.4 ml, 0.8 ± 13. 1 ml, and 2% ± 14% for end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF), respectively. Numerical analysis conducted on MRI contours of LV endocardial borders showed that with six coaxial sections the average coeffi-cient of error was <1% for the EDV and ESV. Three-dimensional echocardiography with six coaxial sections provides unbiased LV volume estimation with minimal geometric error. Received: February 10, 2000 / Accepted: May 23, 2000     

Lack of agreement between left ventricular volumes and ejection fraction determined by two-dimensional echocardiography and contrast cineangiography in postinfarction patients

OBJECTIVE: To assess the agreement between left ventricular (LV) volumes and ejection fraction (EF) determined by two-dimensional echocardiography (2-D echo) and by cineangiography in postinfarction patients. Design: LV end-diastolic and end-systolic volumes indexed (EDVI and ESVI) to body surface area as well as EF were determined by both methods in all patients. Setting: Multicenter trial conducted in five university hospitals. PATIENTS: 63 patients, 61 male, two female, mean age 55.5 +/- 10.4 years, suffering from a recent myocardial infarction. Eighty-one pairs of measurements were available. METHODS: The results of biplane 2-D echo measures, using apical four-chamber (4C) and two-chamber (2C) views were compared to those of a 30 degrees right anterior oblique cineangiography projection, using either the apical method of discs or the area-length 2-D echo method. Moreover, eyeball EF was estimated at 2-D echo and cineangiography, and was compared to the conventional methods. The agreement between results was assessed by the Bland and Altman method. RESULTS: The agreement between 2-D echo and cineangiography results was poor. Mean differences (MD) were -21.8 (EDVI, ml/m(2)), -9.5 (ESVI, ml/m(2)), and -0.9 (EF, %), respectively for 2-D echo method of discs versus cineangiography, and -23.2, -9.3, and -5.7 for area-length 2-D echo versus cineangiography. For EF (%), MD was -3.6 for eyeball cineangiography versus cineangiography, -1.3 for eyeball 2-D echo versus method of discs, and +0.30 for eyeball 2-D echo versus area-length 2-D echo, respectively. Two-dimensional echo is likely to underestimate LV volumes compared to cineangiography, especially for largest volumes. Even for EF, discrepancies are large, with a lack of agreement of 21%-25% between conventional methods, but agreement is better between eyeball EF and usual methods. CONCLUSIONS: Even with modern echocardiographic devices, agreement between 2-D echo and cineangiography-derived LV volumes and EF remains moderate, and both methods must not be considered interchangeable in clinical practice.     

实时三维超声心动图与磁共振对比评价左心室射血分数≥45%患者的左心室容量

目的:评价实时三维超声心动图(RT3D)测量左心室射血分数(LVEF)≥45% 成年人左心室容量的准确性和重复性.方法:选取因各种不同原因进行心脏磁共振(MRI)检查显示 LVEF ≥45%的患者37例,同时进行RT3D检查.RT3D检查采用Philips iE-33型超声心动图仪,左心室容量及左心室功能的分析通过TomTec工作站用人工描记法完成,并与MRI所得结果相比较.结果:MRI测量的左心室舒张末期容量(EDV)为:60～208.76(110.48±33.50)ml,左心室收缩末期容量(ESV)为:19～102.4(45.80±17.84 )ml,LVEF为:45.40～71.10(59.13±7.24)%.RT3D测量的EDV为:42.8～ 211.9(100.64±34.48)ml,ESV为:14.30 ～94.54(44.08 ±17.62)ml,LVEF为:35.1～73.4(56.70±7.02)%.与MRI相比,RT3D低估EDV(P＜0.01,r=0.842,y=0.867x+4.88,SEE=18.86ml),二者平均相差(-9.84±38.26) ml.RT3D同时低估ESV,二者相比差异无统计学意义(P＞0.05,r=0.846,y=0.835x+5.82,SEE=9.53 ml),二者平均相差(-1.71±19.68)ml.RT3D所测的LVEF稍小于MRI所测得的LVEF,二者相比差异有统计学意义(P＜0.05,r=0.616,y=0.597x+21.38,SEE=5.61%),平均相差(-2.42±12.5 )%.在不同观察者间及观察者自身不同时间内测量的RT3D,结果显示良好的重复性.结论:与MRI相比,RT3D测量成人患者的左心室容量及LVEF有较好的准确性和重复性.     

Left ventricular volumes and ejection fraction by single plane two-dimensional apex echocardiography

Left ventricular end-diastolic and end-systolic volumes andejection fraction were calculated by means of single plane two-dimensionalapex echocardiography (echo) in 34 consecutive patients undergoingleft ventricular cine-angiography (angio). Adequate echocardiographicstudies could be obtained in 30 patients. Of these 10 were normal,10 had valvular heart disease and 10 coronary artery disease.We consistently used the right anterior oblique equivalent viewbecause of its comparability with the cine-angiographic rightanterior oblique projection. Stop frames from the tape-recordedtwo-dimensional echocardiograms were processed with the samecomputer programme already in use for cine-angiographic measurements.Goodcorrelations were found between echo and angio for end-diastolicand end-systolic volume index (r=0.84 and r=0.85, respectively)and for ejection fraction (r = 0.91). Thus two-dimensional apexechocardiography using the right anterior oblique equivalentview offers a simple non-invasive means of calculating leftventricular volumes and ejection fraction     

Determination of left ventricular volume by two-dimensional echocardiography: comparison with magnetic resonance imaging

Left ventricular volume was determined in 12 healthy volunteersusing a newly developed two-dimensional echocardio-graphic delineationmethod. The results were compared with those of magnetic resonanceimaging, which served as the method of reference. Left ventricularend-diastolic volume was 123 ± 12 ml, echocardiographicallydefined, and 121 ± 12 ml calculated with magnetic resonanceimaging. End-systolic volume was 41 ± 7 ml on echocardiographyand 37±6 ml on magnetic resonance imaging. Left ventricularejection fraction was 67 ± 4%, echocardiographicallydefined, and 70 ± 5%, calculated with magnetic resonanceimaging. There was no statistical difference for any of themeasured parameters. Interstudy and inter-observer variabilitywas minimal. In conclusion, in healthy volunteers left ventricularvolume was accurately defined, using this newly developed two-dimensionalechocardiographic delineation method. During endocardial delineationa dynamic display is continuously available on a second window,allowing precise visual edge-detection. Moreover, correctionscan be made easily and quickly. These two advantages enhancethe accuracy of the method, even in cases of poor echogenicity.     

Comparison of two- and three-dimensional echocardiography with sequential magnetic resonance imaging for evaluating left ventricular volume and ejection fraction over time in patients with healed myocardial infarction

Echocardiographic follow-up of left ventricular (LV) volumes is difficult because of the test-retest variation of 2-dimensional echocardiography (2DE). We investigated whether the accuracy and reproducibility of real-time 3-dimensional echocardiography (RT3DE) would make this modality more feasible for serial follow-up of LV measurements. We performed 2DE and RT3DE and cardiac magnetic resonance imaging (MRI) in 50 patients with previous infarction and varying degrees of LV function (44 men; 61 +/- 11 years of age) at baseline and after 1-year follow-up. Images were obtained during breath-hold and measurements of LV volumes and ejection fraction were made offline. Over follow-up, end-diastolic volume decreased from 192 +/- 53 to 187 +/- 60 ml (p <0.01), end-systolic volume decreased from 104 +/- 51 to 95 +/- 53 ml (p <0.01), and ejection fraction increased from 48 +/- 12% to 51 +/- 12% (p <0.01). MRI showed that LV mass shrank from 183 +/- 39 to 182 +/- 37 g (p <0.01). The correlation between change in RT3DE and change in MRI was greater than the correlations of 2DE with MRI for measurement of end-diastolic volume (r = 0.47 vs 0.02, p <0.01), end-systolic volume (r = 0.44 vs 0.17, p <0.01), and ejection fraction (r = 0.58 vs -0.03, p <0.01). The change in end-diastolic volume between baseline and follow-up with RT3DE (-4 +/- 20, p <0.01) was similar to that with MRI but was unrecognized by 2DE (4 +/- 19, p = 0.09). There was good test-retest and inter- and intraobserver correlation within RT3DE for volumes, ejection fraction, and mass. In conclusion, if sequential measurement of LV volumes is used to guide management decisions, 3DE appears preferable to 2DE.     

Comparison of blood volume characteristics in anemic patients with low versus preserved left ventricular ejection fractions

Anemia is a significant co-morbidity in patients with heart failure (HF) irrespective of the ejection fraction and is routinely quantified by hemoglobin concentration. Hemodilution as a cause of anemia has been described in systolic HF. The aim of this study was to further investigate the effects of plasma volume in patients with HF by (1) assessing the prevalence of dilutional anemia in patients with anemia and preserved ejection fractions and (2) exploring the relation between hemoglobin and red cell volume in these patients. Forty-six patients with anemia (as determined by standard hemoglobin measurement), 22 with HF and low ejection fractions (HFLEF) and 24 with HF and preserved ejection fractions (HFPEF), all underwent plasma volume measurement with iodine-131-labeled albumin. Hemoglobin values did not differ between subjects with HFLEF and those with HFPEF (10.8 +/- 1.0 vs 11.0 +/- 1.0 g/dl, p = 0.55), but a red cell deficit was found in 88% of patients with HFPEF compared with 59% of those with HFLEF (p = 0.04). This was the result of a higher prevalence of an expansion of plasma volume in patients with HFLEF (100%) compared with those with HFPEF (71%). Among all patients, no correlation was found between hemoglobin and red cell volume (r = 0.09, p = 0.54), but a correlation did exist in patients with normal blood volumes (r = 0.55, p = 0.02). In conclusion, dilutional anemia caused by an expansion in plasma volume without a red cell deficit occurs more commonly in patients with HFLEF than those with HFPEF, and hemoglobin does not correlate with red cell volume in patients with anemia and HF.     

Comparison of digital intravenous ventriculography with direct left ventriculography for quantitation of left ventricular volumes and ejection fractions

Digital images of the left ventricle obtained at 30 frames/second from continuous fluoroscopy after intravenous injection of contrast medium (digital intravenous Ventriculography) were used to estimate left ventricular (LV) volumes and ejection fraction with use of several techniques for identifying the ventriculographic silhouette. The digital technique was compared with direct contrast left Ventriculography in 26 patients undergoing diagnostic cardiac catheterization. End-diastolic and end-systolic volumes calculated from digital intravenous and direct left ventriculograms were obtained with use of a standard area-length formula. Both end-diastolic volume (EDV) (r = 0.88, y = 1.06x ? 17.1 ml) and end-systolic volume (ESV) (r = 0.89, y = 0.96x + 0.43 ml) determined from digital intravenous ventriculography (mask mode images) correlated closely with those obtained by direct left ventriculography. Combining the EDV and ESV to define the relation between the 2 techniques yielded an even closer correlation (r = 0.96). There was also good correlation between the 2 techniques for measurement of ejection fraction (r = 0.81, standard error of the estimate 6.7%). Measurements from direct left Ventriculography were frequently invalidated by ventricular arrhythmias during the time of opacification of the left ventricle; this was rarely the case for digital intravenous Ventriculography. It is concluded that area-length estimates of LV volumes and ejection fraction can be accurately obtained from digital processing of fluoroscopic LV images after intravenous injection of contrast medium.     

Importance of imaging method over imaging modality in noninvasive determination of left ventricular volumes and ejection fraction: assessment by two- and three-dimensional echocardiography and magnetic resonance imaging

OBJECTIVES: This study sought to determine the concordance between biplane and volumetric echocardiography and magnetic resonance imaging (MRI) strategies and their impact on the classification of patients according to left ventricular (LV) ejection fraction (EF) (LVEF). BACKGROUND: Transthoracic echocardiography and MRI are noninvasive imaging modalities well suited for serial evaluation of LV volume and LVEF. Despite the accuracy and reproducibility of volumetric methods, quantitative biplane methods are commonly used, as they minimize both scanning and analysis times. METHODS: Thirty-five adult subjects, including 25 patients with dilated cardiomyopathies, were evaluated by biplane and volumetric (cardiac short-axis stack) cine MRI and by biplane and volumetric (three-dimensional) transthoracic echocardiography. Left ventricular volume, LVEF and LV function categories (LVEF > or =55%, >35% to <55% and < or =35%) were then determined. RESULTS: Biplane echocardiography underestimated LV volume with respect to the other three strategies (p < 0.01). There were no significant differences (p > 0.05) between any of the strategies for quantitative LVEF. Volumetric MRI and volumetric echocardiography differed by a single functional category for 2 patients (8%). Six to 11 patients (24% to 44%) differed when comparing biplane and volumetric methods. Ten patients (40%) changed their functional status when biplane MRI and biplane echocardiography were compared; this comparison also revealed the greatest mean absolute difference in estimates of EF for those subjects whose EF functional category had changed. CONCLUSIONS: Volumetric MRI and volumetric echocardiographic measures of LV volume and LVEF agree well and give similar results when used to stratify patients with dilated cardiomyopathy according to systolic function. Agreement is poor between biplane and volumetric methods and worse between biplane methods, which assigned 40% of patients to different categories according to LVEF. The choice of imaging method (volumetric or biplane) has a greater impact on the results than does the choice of imaging modality (echocardiography or MRI) when measuring LV volume and systolic function.