Assessment of Left Ventricular Volumes with Echocardiography and Cardiac Magnetic Resonance Imaging: Real-Life Evaluation of Standard versus New Semiautomatic Methods


Routine quantitative assessment of left ventricular (LV) volumes with echocardiography is hindered by time-consuming methods requiring a manual trace of the LV cavity from two apical two-dimensional planes. Thus, the aim of this study was to evaluate faster new semiautomatic echocardiographic methods that could represent a feasible alternative for the assessment of LV volumes and ejection fraction (EF) in clinical practice.


Two semiautomatic methods, the automated EF (Auto-EF) for two-dimensional echocardiography and the 4D Auto LVQ tool for three-dimensional echocardiography (3DE), were compared with the biplane modified Simpson’s method and cardiac magnetic resonance (CMR) imaging in 47 patients. To evaluate the accuracy of volumetry, additional in vitro measurements using water-filled latex balloons were performed with both modalities.


Results of balloon volumetry by echocardiography and CMR measurements were in good agreement with real balloon volumes. The mean LV EF was 45 ± 11% by Auto-EF, 45 ± 11% by 3DE, 48 ± 11% by Simpson’s method, and 54 ± 12% by CMR. Linear regression and Bland-Altman analyses showed good associations for semiautomatic methods with Simpson’s method (Auto-EF, r = 0.85, bias = 3%, limits of agreement [LOA] = 12%; 3DE, r = 0.79, bias = 3%, LOA = 14%), as well as with CMR (Auto-EF, r = 0.74, bias = 9%, LOA = 17%; 3DE, r = 0.73, bias = 9%, LOA = 17%). Intra- and interobserver variability were 6% and 12% with Auto-EF and 8% and 11% with 3DE, respectively.


Good correlations between semiautomatic echocardiographic parameters for assessment of LV volumes and EF could be observed when compared with Simpson’s method or CMR. However, intertechnique agreement analysis of absolute LV volumes revealed considerable differences, with significant underestimation of volumes and EF with respect to CMR.

Many diagnostic and treatment decisions in cardiovascular care include left ventricular (LV) function as a critical component. The indication for the implantation of an internal cardioverter-defibrillator serves as a good example.

Among the different tools for LV function analysis, transthoracic echocardiography is most widely applied. Current guidelines recommend the use of the biplane method of disks (modified Simpson’s method) for the determination of LV volumes and calculation of ejection fraction (EF). However, manual tracing of the end-diastolic and end-systolic LV cavity can be time consuming and challenging. New semiautomatic methods based on backscatter recognition of endocardial borders have been developed to overcome these limitations, namely, the automated EF (Auto-EF) for two-dimensional (2D) echocardiography and the 4D Auto LVQ tool, an algorithm for three-dimensional echocardiography (3DE). Although the feasibility of these new methods has been established in previous studies, their relative performance in clinical routine settings remains to be determined.

Therefore, we conducted a prospective study comprising two parts. The aim of the first, experimental part was to validate the accuracy of volume assessment with echocardiography and cardiac magnetic resonance (CMR) by use of water-filled latex balloons as an in vitro model. In the second, clinical part, we aimed to evaluate the performance of Auto-EF and the 4D Auto LVQ tool for the assessment of LV volumes and function during routine clinical practice and to compare the agreement of the two semiautomatic methods with the modified biplane Simpson’s method as well as with CMR. Care was taken to follow the specific guideline recommendations for LV volume quantification with either echocardiography or CMR.


In Vitro Volume Validation

Ten water-filled latex balloons of different size and shapes were used to validate the accuracy of Simpson’s method for 2D echocardiography ( Figure 1 A), 4D Auto LVQ for 3DE ( Figure 1 B), and the Extended MR Workspace software for CMR ( Figure 1 C). To determine the balloon’s volume with Simpson’s method and 3DE, we used the visible inner layer of the latex membrane as the boundary. On CMR images, the real inner layer was not detectable, so the outermost margin of the balloon was used as the boundary. Apparently internal balloon borders seen on CMR images depict an artifact known as Gibbs ringing, which represents a mathematical limitation of the Fourier transform.

Figure 1

Long axis ( upper row ) and short-axis ( lower row ) view of one example latex balloon on 2D echocardiography (A) , reconstructed 3DE (B) , and CMR imaging (C) .

Balloon volumes were assessed on the same day with all methods and then compared with their real volumes. Water-filled balloon volumes were determined by measuring their weights on a laboratory precision balance and subtracting the weights of the empty balloons, assuming that under standard conditions 1 mL equals 1 g pure water weight. The Auto-EF tool could not be tested as described because it needs a small dynamic volume change of ≥10% to work at all.

Study Population

All patients undergoing clinically indicated CMR examinations in our cardiology department within a time span of 1 month were invited to participate in this study ( n = 183). Forty-seven patients agreed to undergo additional comprehensive echocardiographic examinations. Clinical characteristics are shown in Table 1 . The patient population was heterogeneous: 15 patients had normal myocardial function without critical coronary artery disease; furthermore, 14 patients with cardiomyopathy (10 dilated, two hypertrophic, two cardiac amyloidosis), 10 patients with coronary artery disease (two with one-vessel, two with two-vessel, and six with three-vessel disease), four patients with different forms of known cardiac arrhythmia and/or conduction disorder (Wolff-Parkinson-White syndrome, premature atrial contractions, paroxysmal atrial fibrillation, premature ventricular beats), two patients after heart transplantation, one patient with an atrial septal defect, and one patient with systemic vasculitis were included. All patients were in sinus rhythm during both examinations. To minimize time-dependent variation of hemodynamic characteristics, echocardiography was commenced <30 min after CMR.

Table 1

Clinical characteristics of the study population

Parameter Value
Age (yrs) 51 ± 19
Men 45%
BMI (mg/m 2 ) 26 ± 4
Heart rate (beats/min) 67 ± 14
SBP (mm Hg) 122 ± 17
DBP (mm Hg) 75 ± 9
NYHA functional class I and II

BMI , Body mass index; DBP , diastolic blood pressure; NYHA , New York Heart Association; SBP , systolic blood pressure.

Data are expressed as mean ± SD.

Standard as well as two new methods for the assessment of LV volumes and function were conducted in the same cohort. Patients with suboptimal echocardiographic image quality were not excluded, to reflect a real-life patient population. The study was carried out prospectively after approval by the Ethics Committee of the University of Heidelberg and in concordance with the Declaration of Helsinki. Written informed consent was obtained from all persons.


All echocardiographic examinations were performed on a commercially available ultrasound machine (Vivid E9 BT 11; GE Vingmed Ultrasound AS, Horten, Norway) according to the guidelines of the American Society of Echocardiography and using a 1.5- to 4.6-MHz phased-array probe (M5S-D) for 2D imaging and an active-matrix four-dimensional volume phased-array probe (4V-D) for 3DE. Image acquisition was conducted in a breath-hold manner, and at least three consecutive heart cycles were recorded after passive end-expiration. The LV endocardium was used as the boundary for volumetric measurements. Papillary muscles and visible trabeculae were part of the blood pool. If endocardial border detection was uncertain, nonvisible parts were interpolated manually. Three different techniques were used to determine LV volumes and function:

  • 1.

    The modified biplane Simpson’s method, as recommended by the American Society of Echocardiography : End-diastolic and end-systolic endocardial borders were traced manually on frozen 2D images obtained from the apical two- and four-chamber views to derive end-diastolic volume (EDV) and end-systolic volume (ESV). The LV EF was calculated according to the formula EF = (EDV − ESV)/EDV × 100%.

  • 2.

    The Auto-EF tool (EchoPAC version 110.1.1 BT 11; GE Vingmed Ultrasound AS) : Using dynamic 2D images of the apical four- and two-chamber views, three anchor points were set within the LV cavity, two at the level of the mitral valve annulus and one at the LV apex. Endocardial borders were then detected and traced automatically by the software during a whole heart cycle to calculate EDV, ESV, and EF. When needed, corrections could be carried out manually ( Figure 2 A).

    Figure 2

    Endocardial border detection by Auto-EF (A) , 4D Auto LVQ (B) , and manual border tracing of a midventricular CMR short-axis slice (C) in end-diastole ( upper row ) and end-systole ( lower row ). All data sets are derived from the same patient, with a moderately reduced EF.

  • 3.

    Three-dimensional echocardiographic analysis using the 4D Auto LVQ tool (EchoPAC version 110.1.1 BT 11; GE Vingmed Ultrasound AS, Trondheim, Norway) : Three-dimensional data sets were acquired, comprising the whole heart in a 90° × 90° pyramidal scan volume and were recorded during breath-hold in passive end-expiration. A multibeat mode over up to six heart cycles was used to achieve high temporal resolution, with frame rates between 30 and 50 frames/sec. After data acquisition, fully automated orientation of the apical four-chamber, two-chamber, and long-axis planes was attempted. Orientation was manually adjusted if needed. Two points were then manually set in end-diastole as well as in end-systole, one at the level of the mitral valve, one at the LV apex, to define basal and apical limits of the LV cavity. Endocardial borders were detected, and values of EDV, ESV, and EF then calculated automatically by the software. Automatic endocardial border detection was manually corrected if the software excluded papillary muscles or visible trabeculae from the LV cavity ( Figure 2 B).

CMR Imaging

A whole-body CMR scanner (1.5-T Achieva; Philips Medical Systems, Best, The Netherlands) was used for image acquisition, applying a short-axis multislice cine steady-state free precession sequence with parallel imaging (8–12 slices; slice thickness, 8 mm; gap, 2 mm; ≥35 phases per cardiac cycle; balanced fast field echo; repetition time, 2.9 msec; echo time, 1.45 msec; reconstructed voxel size, 1.5 × 1.5 × 8 mm acquisition; sensitivity encoding factor, 2). According to recent guidelines, the LV cavity, defined as the border between compacted and noncompacted myocardium, was manually traced in each short-axis slice in end-diastole and end-systole ( Figure 2 C) with a commercially available software package to calculate EDV, ESV, and EF (Extended MR Workspace version; Philips Medical Systems). Papillary muscles were part of the blood pool.

Statistical Analysis

Statistic analysis was carried out with the SigmaStat version 3.5 (Systat Software, Inc, Chicago, IL), and graphs were drawn with GraphPad Prism version 5 (GraphPad Software, Inc, La Jolla, CA). To test for normal distribution, the Kolmogorov-Smirnov test was used. Significance was tested using Student’s t test or the Mann-Whitney-Wilcoxon test in case of non-normality. P values < .05 were considered statistically significant. Method comparison was conducted with linear regression analyses and Bland-Altman plots. Pearson’s correlation coefficient was used for normal distributed values and Spearman’s correlation coefficient in case of non-normality. Twenty randomly chosen data sets were reanalyzed in a blinded fashion by the same and by a second experienced sonographer to assess intra- and interobserver variability. These values are expressed as coefficients of variation and were calculated by the standard deviation of the differences between the two measurements, divided by their mean value and expressed as percentages.


In vitro measurements revealed excellent correlations when echocardiographic and CMR values were compared with the true volumes of the 10 water-filled latex balloons. The true mean volume was 218 ± 118 mL. Mean volume was 209 ± 119 mL by 3DE, 206 ± 121 mL by Simpson’s method, and 226 ± 121 mL by CMR, resulting in a bias of 8.6 mL for 3DE, 11.8 mL for Simpson’s method, and −8.7 mL for CMR ( Figures 3 A–3C).

Figure 3

Linear regression analysis and corresponding Bland-Altman plots for phantom volume assessment by the modified Simpson’s method ( red ) (A) , 3DE ( blue ) (B) , and CMR imaging ( green ) (C) .

LV volumes and EF could be assessed in all 47 patients. However, echocardiographic image quality was rated as suboptimal in 45% of these patients, whereas CMR images were generally of good quality. Mean values and standard deviations of EDV, ESV, EF, and EF assessment time for Simpson’s method, Auto-EF, 3DE, and CMR are shown in Table 2 and Figure 4 . Except for EF assessment time, differences were not significant when Auto-EF and 3DE were compared with Simpson’s method. Compared with CMR, both LV volumes and EF showed significantly lower values when determined by Auto-EF and 3DE.

Table 2

EDV and ESV, EF, and time for assessment of EF for each method

Method EDV (mL) ESV (mL) EF (%) EF assessment time (sec)
Auto-EF 113 ± 36 63 ± 28 45 ± 11 74 ± 18
3DE 122 ± 51 69 ± 40 45 ± 11 261 ± 93
Simpson’s method 118 ± 41 63 ± 33 48 ± 11 113 ± 30
CMR 184 ± 62 89 ± 52 54 ± 12 139 ± 18

Data are expressed as mean ± SD.

Figure 4

Box-and-whisker plot of LV volumes, EF, and assessment time for calculation of EF. Boxes show the first ( bottom ), second ( inner line indicates median), and third ( top ) quartile, and whiskers represent the limits of 1.5 times the interquartile range. Values below or above these limits are depicted as outliers. Results of Auto-EF are depicted in orange ; other colors as in Figure 3 . P < .01; ∗∗ P < .001; ∗∗∗ P < .0001.

Results of linear regression and Bland-Altman analysis of EDV, ESV, and EF are summarized in Table 3 . Correlation coefficients were 0.85 for Simpson’s method and Auto-EF (SEE = 6.0, P < .001) and 0.79 for Simpson’s method and 3DE (SEE = 6.9, P < .001). Corresponding Bland-Altman plots show a bias of 3% for both comparisons, with limits of agreement (LOA) of 12% for Auto-EF and 14% for 3DE ( Figures 5 A and 5B). Linear regression analysis of CMR with semiautomated echocardiographic methods revealed correlation coefficients of 0.74 for CMR and Auto-EF (SEE = 8.1, P < .001) and 0.73 for CMR and 3DE (SEE = 8.3, P < .001). In both corresponding Bland-Altman plots, a bias of 9% and LOA of 17% were calculated ( Figures 5 C and 5D).

May 31, 2018 | Posted by in CARDIOLOGY | Comments Off on Assessment of Left Ventricular Volumes with Echocardiography and Cardiac Magnetic Resonance Imaging: Real-Life Evaluation of Standard versus New Semiautomatic Methods

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