Semi-automated Border Detection Research Articles

Left Atrial Volumes and Function: Evaluation With Real-Time 3D Echocardiography in an Acute Care Setting

Background: Limited data are available about feasibility and clinical value of left atrium (LA) quantitative evaluation obtained from real time 3D (RT-3D) echocardiography in critically ills. Objectives: Aims of this study were: 1) to evaluate feasibility of RT-3D echocardiography for LA evaluation in an acute care setting and in a population including a majority of critically ills; 2) to evaluate correlation between two-dimensional (2D) and RT-3D echocardiographic LA quantitative evaluation; 3) to assess clinical consistency and prognostic value of LA measurements obtained from RT-3D images in subjects without CV diseases and in patients with AF and CHF, evaluated in the acute phase of the disease. Patients and Methods: In 382 subjects admitted in the emergency department (ED), we evaluated maximal (Volmax) and minimal (Volmin) LA volumes and LA emptying fraction (LA-EF), from RT-3D images, with a semiautomated border detection program. A follow-up was performed in order to evaluate all-cause mortality and new hospital admission for cardiovascular events. Results: The correlation between measures obtained from 2D and 3D was good (LA Volmax: r = 0.896, P < 0.001; Volmin: r = 0.906, P < 0,001; LA EF: r = 0.749, P < 0.001). Among 77 normal subjects, people aged ≥ 65 years demonstrated comparable LA dimensions with younger subjects (LA Volmax: 25 ± 11 vs 20 ± 7 mL/m 2 , Volmin: 11 ± 7 vs 8 ± 5 mL/m 2 ). Subjects with normal left ventricular ejection fraction showed LA Volmax significantly lower than patients with LV systolic dysfunction or congestive heart failure (23 ± 11 vs 29 ± 10 vs 33 ± 12 mL/m 2 , P < 0.05). Patients in atrial fibrillation showed a significantly dilated LA compared with subjects in sinus rhytm (24 ± 11 vs 37 ± 22 mL/m 2 , P < 0.05). LA dimensions were significantly higher in non-survivors (LA Volmax: 33 ± 9 vs 25 ± 9 mL/m 2 ), in patients with a new hospital admission for cardiovascular disease (LA Volmax: 34 ± 13 vs 23 ± 10 mL/m 2 ) or with a new AF episode (LA Volmax: 40 ± 12 vs 24 ± 11 mL/m 2 , all P < 0.005). Conclusions: RT-3D evaluation of LA volumes and function is feasible in a non selected series of critically ills. LA dilation was associated with a worse outcome in terms of morbidity and mortality.

Semi-automatic border detection software for the quantification of arterial lumen, intima-media and adventitia layer thickness with very-high resolution ultrasound

BackgroundThe aim was to evaluate the accuracy, precision and feasibility of semi-automatic border detection software (AMS) in comparison to manual electronic calipers (EC) in the analysis of arterial images obtained with transcutaneous very-high resolution vascular ultrasound (VHRU, 25–55 MHz). Methods100 images from central elastic and peripheral muscular arteries were obtained on two separate imaging occasions from 10 healthy subjects, and independently measured with AMS and EC. ResultsNo bias between AMS and EC was found. The intraobserver coefficients of variation (CV) for carotid lumen dimension (mean dimension 5.60 mm) was lower with AMS compared with EC (0.4 vs. 1.9%, p = 0.033; N = 20). No consistently significant differences in intra, inter or test-retest CVs were observed overall for muscular artery dimensions between AMS and EC. The intra CV for adventitial thickness (AT, mean 0.111 mm; 15.6 vs 24.8%, p = 0.011; N = 41) and inter CV for intima-media thickness (IMT, mean 0.219 mm; 14.3 vs. 21.2%, p = 0.001; N = 58) obtained with AMS in higher quality thin muscular artery images was lower compared with EC. The mean reading time was significantly lower with AMS compared with EC (71.5 s vs. 156.6 s, p < 0.001). ConclusionAMS is accurate, precise, and feasible in the analysis of arterial images obtained with VHRU. Minor, although statistically significant, differences in the precision of AMS and EC-systems were found. The precision of AMS was superior for AT and IMT in higher quality images likely related to a decrease in the technical variability imposed by the observer.

Diferencias en la infraestimación de los volúmenes del ventrículo izquierdo entre 2 sistemas de ecocardiografía 3D. Comparación con resonancia magnética

Introduction3-D echocardiography (3DE) is superior to the 2-D technique in assessing left ventricular (LV) volumes and ejection fraction (EF). This study compares two 3DE systems with cardiac magnetic resonance imaging (cMRI): single-beat 3DE with automated endocardiac border detection (Siemens SC2000;A) and 3DE with multi-beat acquisition and semi-automated endocardiac borders detection (Philips iE33;B). MethodsA 3DE with single-beat acquisition and automated border detection (A) and 3DE with multi-beat acquisition and semi-automated border detection (B) was performed on 22patients referred for a study using cMRI. ResultsThe mean volumes and EF measured by cMRI were: DTV: 211.07±85.4mL; STV: 119.2±89.25mL; EF: 48.67±20.07%. The correlation between cMRI and the two 3DE systems was excellent for the DTV (rhoA 0.912; rhoB 0.907; P<.0001), STV (rhoA 0.877; rhoB 0.945; P<.0001) and EF (rhoA 0.974; rhoB 0.951; P<.0001). The Bland-Altman analysis showed an underestimation of the LV volumes with both 3DE systems, with the difference being lower in systemA than in systemB (–40±50.2 vs –82.2±40.9mL, respectively for DTV; –16±44.4 vs –43±43.5mL, respectively for STV; P=.001). There were no differences in the measurement of EF between the 3imaging techniques. Conclusion3DE underestimates LV volumes. In our series, this underestimate was lower in the system with single-beat acquisition and automated border detection.

Measurement of Left and Right Atrial Volume in Patients Undergoing Ablation for Atrial Arrhythmias: Comparison of a Manual versus Semiautomatic Algorithm of Real Time 3D Echocardiography

Real time full-volume 3D echocardiography (3DE) allows rapid and noninvasive measurement of left (LA) and right atrial (RA) volume without geometric assumptions. Different algorithms from different commercial providers are available. Older software requires manual tracing of endocardial contours. Recently, software with semiautomatic endocardial contour-finding algorithms has become available, which considerably speeds up the procedure. Our aim was to compare, in the same dataset, both LA and RA volumes determined by an algorithm involving manual tracing to the corresponding volumes obtained by an algorithm with semiautomatic contour detection. Maximal atrial volumes were measured in 88 patients using a multiplane interpolation method algorithm based on manual planimetry of 8 slices. These volumes were compared with volumes determined by the QLAB 8.1 software using semiautomatic border detection. Linear regression showed excellent correlation between volumes determined by manual and by semiautomatic software for both LA and RA (r(2) = 0.90 and 0.89, respectively, P < 0.001). Bland-Altman analysis of manual versus semiautomatic volume determination showed narrow 95% limits of agreement (-15.9 to +12.0 mL for LA volume and -13.9 to +12.2 mL for RA volume) with a minimal bias of -1.9 ± 7.0 mL and -0.8 ± 6.5 mL, respectively, by the semiautomatic method. The semiautomatic border detection method shows excellent correlation for maximal LA and RA volume determination compared to the more time-consuming, multiplane interpolation method, with only slight underestimation. The results indicate that values of LA and RA volumes obtained by either algorithm can be compared, for example, during follow-up examinations.

Assessment of right ventricular volumes in hypoplastic left heart syndrome by real-time three-dimensional echocardiography: comparison with cardiac magnetic resonance imaging

Accurate assessment of right ventricular (RV) volumes and function is important in patients with hypoplastic left heart syndrome (HLHS). We prospectively sought to determine the reproducibility of three-dimensional (3D) echocardiography and its agreement with cardiac magnetic resonance imaging (CMR) in HLHS. Twenty-eight patients underwent CMR followed immediately by transthoracic 3D echocardiography under general anaesthesia. Semi-automated border detection software was used to determine echocardiographic RV volumes. Inter- and intra-observer variability, correlation and levels of agreement between techniques were determined. The median age was 0.37 years (0.18-9.28 years) and weight 6.24 kg (3.42-32.50 kg). Intra- and inter-observer variability was excellent for both techniques. Median (range) measurements for 3D echocardiography and CMR were; end-diastolic volume (EDV) 23.6 mL (6.5-63.2) and 30.6 mL (11.8-87.9), end-systolic volume (ESV) 12.6 mL (3.7-37.0) and 14.9 mL (5.8-33.9), stroke volume (SV) 11.2 mL (2.8-33.0) and 17.1 mL (6.0-54.1), ejection fraction (EF) 48.2% (31.2-64.9), and 56.5% (42.7-72.2). Correlation coefficients were r = 0.85, 0.84, 0.83, and 0.74, respectively (P < 0.01 for all). Volumetric data were expressed as a percentage of the echocardiographic volume to CMR volume. When compared with CMR, 3D echocardiography underestimated EDV, ESV and SV by 26.7% (SD ± 20.2), 10.6% (±28.1), and 37.5% (±20.1), respectively. The difference in volume appeared largest at low ventricular volumes. EF was 8.3% (±7.3) lower by 3D echocardiography compared with CMR. Both 3D echocardiography and CMR volumes appear highly reproducible. Measurements obtained by 3D echocardiography are significantly lower than those obtained by CMR, with wide limits of agreement such that these two methods cannot be used interchangeably.

Consolidated normal reference limits for right ventricular quantification by 3-dimensional echocardiography using a novel meta-analytic approach

Purpose: Three-dimensional echocardiography (3DE) has superior accuracy and reproducibility for quantification of right ventricular (RV) size and function. However, the lack of consolidated normative data has been a factor in limiting its widespread clinical use. Methods: We performed a comprehensive review of the literature to identify all published studies that measured RV parameters by 3DE in healthy control groups. The parameters of interest were ejection fraction (RVEF), end-diastolic volume (RVEDV), end-systolic volume (RVESV); both non-indexed and indexed to body surface area. Age- and sex-specific normative data were extracted when available. Using a novel statistical approach, we performed a random-effects meta-analysis of these normative data to generate pooled mean values, upper reference values (mean + 2SD), lower reference values (mean – 2D), and 95% confidence intervals. Results: We identified 29 studies encompassing a total of 1610 healthy individuals. Semi-automated border detection algorithms were used in most studies. The results of the normative data meta-analysis are shown in the table. Using these results, the following 3DE cutoffs are recommended to define abnormality: RVEF 124.0 mL, RVEDVi >84.3 mL/m2, RVESV >61.0 mL, and RVESVi >38.5 mL/m2. Few studies reported age-specific (N=2) and sex-specific (N=4) data. Each decade of advancing age was associated with a gradual mild decline in volumes and preserved RVEF. Female sex was associated with mildly higher RVEF and moderately lower indexed and non-indexed volumes compared to males. View this table: Meta-analysis of normal reference values Conclusions: The proposed reference limits consolidate the body of normative data for RV quantification using 3DE, and thus should facilitate the clinical adoption of this technique. Further data are needed to evaluate age- and sex-specific differences.

Non-invasive quantification of right ventricular systolic function by echocardiography: a new semi-automated approach

Right ventricular (RV) function determines long-term outcome in many cardiopulmonary diseases. However, the assessment of RV function is time-consuming and surrogate parameters derived from two-dimensional (2D) or Doppler echocardiography show poor consistency. Forty consecutive patients were examined within 30min after magnetic resonance imaging (MRI) with comprehensive echocardiography, including strain imaging and real-time three-dimensional echocardiography. A new parameter, the RV automated systolic index (RV-ASI), was obtained from the apical four-chamber view using semi-automated border detection. RV-ASI could be assessed by 2D echocardiography in 38 of 40 patients. RV ejection fraction assessed by MRI was 48±9%, while RV-ASI was 52±11% (r=0.74, SEE=6%, p<0.0001). Intra- and inter-observer variabilities were 7.5 and 8.9%, respectively. An RV-ASI cut-off value of 52% in this cohort was able to differentiate between normal and impaired RV function (AUC 0.92, sensitivity 87%, specificity 93%). In this study, the RV-ASI showed to be an easy, rapid to assess and reliable tool for quantification of right ventricular function. Furthermore, this index can complement the assessment of right ventricular mechanics by 2D strain imaging for efficient and comprehensive non-invasive evaluation of right ventricular function.

A new quantification method for mechanical dyssynchrony with three-dimensional echocardiography; segmental time and volume loss for prediction of response to cardiac resynchronisation therapy

A novel method to assess left ventricular (LV) mechanical dyssynchrony using three-dimensional echocardiography (3DE) and semi-automated border detection was investigated, which might be superior in prediction of response to cardiac resynchronisation therapy (CRT) compared to traditional measures that rely solely on segmental time-to-contraction. Twenty-eight heart failure patients underwent real-time 3DE before CRT and at 6–12 months follow-up. Analysis of 3DE was performed using TomTec Research-Arena software featuring semi-automated endocardial border detection. The following echocardiographic parameters were calculated in a 16-segment model: areas under segmental time-volume-curves (STV); delay between contraction of the earliest and latest segment (L-E); and standard deviation of segmental time-to-contraction (SDI). Response to CRT was defined as ≥10% decrease in LV end-systolic volume at follow-up. Baseline Pre-STV had a higher sensitivity than SDI for prediction of response (94 vs 67%, respectively), with equal specificity (78%) and a higher area under receiver operator characteristic curve. In contrast, L-E had a sensitivity of 83% and a specificity of 56%. Using 3DE, methods that combine segmental time-to-contraction with segmental contractility might improve LV dyssynchrony assessment compared to traditional methods based on segmental time-to-contraction alone. Pre-STV might be a better predictor of response to CRT than SDI.

Variables Influencing the Accuracy of 2‐Dimensional and Real‐time 3‐Dimensional Echocardiography for Assessment of Small Volumes, Areas, and Distances

The aim of this study was to assess the validity, accuracy, and reproducibility of real-time 3-dimensional (3D) echocardiography for small distances, areas, and volumes. Real-time 3D echocardiography using matrix technology was performed in small calibrated tissue-mimicking phantoms and compared with 2-dimensional (2D) echocardiography. In a systematic variation of variables on data acquisition and analysis including different 3D workstations (manual disk summation versus semiautomatic border detection), the relative contributions of sources of errors were determined. The clinical relevance of the in vitro findings was assessed in 5 neonates and infants. Distance calculation was valid (mean relative error ± SD, -0.15% ± 1.2%). Underestimation of areas and volumes was significant for both 2D and 3D echocardiography (area: 2D, -7.0% ± 2.9%; 3D, -6.0% ± 2.8%; volume: 2D, -13.1% ± 4.5%; 3D, -6.7% ± 2.5%; P < .05). Adjustment of compression and gain on data acquisition (difference of the means: 2D, 11.6%; 3D, 17.9%), gain on postprocessing (3D, 3.4%), and the border detection algorithm on analysis (2D, 4.8%; 3D, 16.6%) had a highly significant effect on volume and area calculations (P < .001). In vivo, compression and gain on acquisition (3D, 19.1%) and the 3D workstation on analysis (3D, 22.2%) had a highly significant impact on left ventricular volumetry (P < .001). Real-time 3D echocardiography is a reliable method for calculation of small distances, areas, and volumes comparable with the size of the neonatal and infant heart. Variables influencing boundary identification during image acquisition and analysis have a significant impact on 2D and 3D area and volume calculations. Standardized protocols are mandatory to avoid these sources of error in both clinical practice and research.

Assessment of Left Ventricular Volumes and Function by Real Time Three‐Dimensional Echocardiography in a Pediatric Population: A TomTec versus QLAB Comparison

Three-dimensional echocardiography (3DE) allows accurate calculation of ventricular volumes despite a remaining geometric assumption on the ventricular shape. Few studies involving full volume reconstruction software have been performed on children. Our aim was to compare the left ventricular (LV) volume measurements obtained with the most used 3D analysis software in a pediatric population. Fifty patients (median age: 9.5 years) without cardiac disease were included in the study. 3DE was performed with the X4-2 or X7-2 matrix probe (ie33, Philips). The LV volume analysis was performed with QLAB 6.0 (semiautomated border detection) and TomTec 4D LV (primary manual tracking with semiautomated border detection). TomTec analysis feasibility amounted to 94% whereas QLAB analysis feasibility only reached 80% (P = 0.037). The analysis time was shorter with QLAB than TomTec (5 ± 2 versus 6 ± 3 minutes, P < 0.05). The stroke volume, end diastolic and end systolic LV volume measurements performed on the 40 patients were strongly correlated (r > 0.97; P < 0.0001) with minimal bias. The LV ejection fraction was well correlated (r = 0.79; P < 0.0001). 3D LV volume quantification is feasible either by using manual or automated reconstruction software in a normal pediatric population. LV Measurements are well correlated. Differences in volume reconstruction algorithms provide specific software performance characteristics. TomTec is a more feasible method but requires a longer analysis time. Further studies are needed to validate the accuracy of the method to calculate enlarged LV volumes in patients with congenital heart diseases.

Evaluación del ventrículo izquierdo por ecocardiografia tridimensional. Comparación con la Cardio-RM

Objective Three-dimensional echocardiography (3DE) is becoming increasingly common in clinical environments. However, the quality of the images depends on the acoustic window, and it can be difficult to identify the endocardial borders. The objective of this study was to evaluate the performance of 3DE in determining the volumes and left ventricular ejection fraction in unselected patients against the gold standard, cardiac magnetic resonance (CMR). Material and methods In 47 unselected patients who underwent CMR, we performed 3DE using a real-time acquisition technique and semiautomatic border detection. Results We excluded 4 patients (8.5%) because they had an extremely deficient acoustic window. In the remaining 43 patients, including those with a suboptimal acoustic window, we obtained the following correlations between 3DE and CMR: end-diastolic volume, 0.71; end-systolic volume, 0.77; ejection fraction, 0.74. Although the end-diastolic volume was systematically underestimated, no significant differences were observed in the ejection fraction. When the 11 patients with suboptimal acoustic windows were excluded, we observed a systematic underestimation of the end-diastolic and end-systolic volumes, which paradoxically gave rise to improved correlation coefficients (0.79, 0.92, and 0.84, respectively) and a more accurate ejection fraction. Conclusions Compared to CMR, 3DE systematically underestimates the ventricular volumes but enables adequate determination of the left ventricular ejection fraction regardless of the quality of the acoustic window.

Full-volume three-dimensional echocardiographic assessment of left ventricular volume in healthy human fetuses

Objective To evaluate the feasibility and accuracy of full volume three-dimensional echocardiography(FV3DE) for quantifying the left ventricular volume in healthy fetuses. Methods Two hundred and twenty-two normal fetuses with gestational ages between 20 and 40 weeks were investigated. Full volume three-dimensional, two-dimensional (2D) and M-mode images were acquired by Philips iE33 system and data was processed offline using QLAB analysis software. Left ventricular end-systolic volume(ESV) and end-diastolic volume ( EDV) were measured using semiautomated border detection echocardiographic techniques, and compared with 2D biplane Simpson's method and M-mode Teichholz formula. Results Thirty-six fetuses with poor three-dimensional images and 5 twin pregnancies were excluded,the study subjects consisted of 181 singleton fetuses. The highest concordance correlation ( r =0.987 for EDV, r =0.988 for ESV) P <0. 001) was noted between 2D biplane Simpson's and FV3DE-derived values with a small bias (0. 332 ml for EDV,0. 135 ml for ESV). The Bland-Altman analysis showed that FV3DE had the best reproducibility than M-mode Teichholz formula and 2D biplane Simpson's method. Intra- and interobserver error of EDV were 2.85% and 4.22% for FV3DE,8.37% and 8.98% for 2D biplane Simpson's rule,30. 63% and 54. 70% for M-mode Teichholz formula. Intra- and interobserver error of ESV were 2.34% and 6. 14% for FV3DE,6. 26% and 11.7% for 2D biplane Simpson's rule,43.06% and 66.03% for M-mode Teichholz formula. Conclusions FV3DE is a novel technique that can be more accurate than conventional methods in quantification of fetal left ventricular volumes, it may provide new insight into evolving fetal cardiac structure and function. Key words: Ultrasonography,prenatal s Fetus; Cardiac volume,left

Semiautomatic Quantification of Left Ventricular Function by Two-Dimensional Feature Tracking Imaging Echocardiography. A Comparison Study with Cardiac Magnetic Resonance Imaging

To evaluate the accuracy of a semiautomatic quantification of left ventricular (LV) volumes and ejection fraction (EF) using two-dimensional (2D) feature tracking imaging (FTI). Thirty-four consecutive subjects (11 patients with dilated cardiomyopathy, 13 with hypertrophic cardiomyopathy, and 10 subjects with no cardiac disease) underwent, on the same day, trans-thoracic echocardiography (TTE) examination, FTI, and cardiac magnetic resonance imaging (MRI), as gold standard, in order to quantify LV volumes and EF. The echocardiographic quantification of LV volumes and EF was determined from four- and two-chamber views using both standard TTE Biplane Simpson's method and a semiautomatic border detection based on FTI. Furthermore, the time for data analysis for each method was measured. The time required for semiautomatic analysis of volumes and EF was significantly lower (P < 0.0001) by FTI (71 seconds) in comparison with standard biplane Simpson's method (93 seconds). LV volumes obtained by FTI were significant underestimated (P < 0.001) in comparison with MRI. Bland-Altman analysis of EDV and ESV using FTI and cardiac MRI showed a low level of agreement for EDV (mean difference = 40.8; SD = 39) and ESV (mean difference = 38.1; SD = 42). On the contrary, no significant difference between FTI and MRI in assessing the LVEF was found; furthermore, a very low bias (2 ± 12) by Bland-Altman analysis was found between FTI and cardiac MRI for the quantification of EF. Semiautomatic quantification of LV volumes using FTI allows an accurate, rapid, easy and reliable assessment of LV EF and a rough estimation of LV volumes.

149 Assessment of left ventricular volumes and function by 3D real-time transthoracic echocardiography in children: Comparison of Qlab and Tomtec full volume reconstruction

Three-dimensional echocardiography (3DE) allows calculation of ventricular volumes without geometric assumption on the ventricular shape. Real Time 3DE is validated to evaluate left ventricular (LV) volumes and function in adults. Accuracy of the two full volume reconstruction softwares Tomtec and Qlab have not been yet studied in children. To apply 3DE in a normal pediatric population and to compare the left ventricular volumes measurements between these two analysing softwares. Fifty pediatric patients (median age 10 years) with normal cardiac anatomy and function were included. 3D transthoracic echocardiography was performed with the X4-2 or X7-2 matrix probe (ie33, Philips Medical Systems, Andover, MA). Off-line left ventricular (LV) volume analysis was performed with QLAB 6.0 (Semi-automated border detection with biplane projections) and TomTec 4D LV analysis (primarily manual tracking with triplane projections and semiautomated border detection). Feasibility was 94% for both softwares. Measurements of LV stroke volume, end-diastolic and end-systolic were strongly correlated (r = 0.96; p < 0.0001). LV ejection fraction measurements were well correlated between the 2 methods (r = 0.78; p <0,0001). Mean LV ejection fraction difference was 3.9% +/- 8. No difference was found between Qlab and Tomtec observer variability. Nevertheless Tomtec inter Observer variability tends to be higher. The analysis time was shorter with QLAB (5 +/- 2 min vs. 6 +/- 3, p < 0.05). 3DE is a feasible and adequate method for LV volume quantification in a normal pediatric population. Qlab analysis is faster, easier and inter-observer variability tends to be smaller. Further studies are needed to validate the accuracy of the method to calculate enlarged LV volumes in patients with congenital heart diseases.

Evaluation of the left ventricle with three-dimensional echocardiography: Comparison with cardiac magnetic resonance

ObjectiveThree-dimensional echocardiography (3DE) is becoming increasingly common in clinical environments. However, the quality of the images depends on the acoustic window, and it can be difficult to identify the endocardial borders. The objective of this study was to evaluate the performance of 3DE in determining the volumes and left ventricular ejection fraction in unselected patients against the gold standard, cardiac magnetic resonance (CMR). Material and methodsIn 47 unselected patients who underwent CMR, we performed 3DE using a real-time acquisition technique and semiautomatic border detection. ResultsWe excluded 4 patients (8.5%) because they had an extremely deficient acoustic window. In the remaining 43 patients, including those with a suboptimal acoustic window, we obtained the following correlations between 3DE and CMR: end-diastolic volume, 0.71; end-systolic volume, 0.77; ejection fraction, 0.74. Although the end-diastolic volume was systematically underestimated, no significant differences were observed in the ejection fraction. When the 11 patients with suboptimal acoustic windows were excluded, we observed a systematic underestimation of the end-diastolic and end-systolic volumes, which paradoxically gave rise to improved correlation coefficients (0.79, 0.92, and 0.84, respectively) and a more accurate ejection fraction. ConclusionsCompared to CMR, 3DE systematically underestimates the ventricular volumes but enables adequate determination of the left ventricular ejection fraction regardless of the quality of the acoustic window.

Right ventricle three-dimensional echography in corrected tetralogy of fallot: accuracy and variability

To evaluate right ventricular (RV) volume and ejection fraction (EF) in adult normal subjects and repaired tetralogy of Fallot (ToF) with 3D trans-thoracic echocardiography (3DE) and a semi-automatic border detection algorithm. Fourteen healthy volunteers and 20 patients with repaired ToF (mean age 31 +/- 14) underwent 3DE and MRI within the same day. Right ventricular end-systolic volume (ESV) and end-diastolic volume (EDV) and EF were measured by two observers using 3DE and compared with MRI measurements. Intra- and interobserver variability of 3DE and agreement between both methods were evaluated using Bland-Altman analysis. Over or underestimation of 3DE in comparison to MRI was assessed using paired t-test. Intra- and interobserver variability of 3DE was excellent with intraclass coefficient of correlation (ICC) ranging from 0.85 to 0.99 and from 0.85 to 0.98, respectively. Three-dimensional echocardiography underestimated ESV and EDV (P < 0.001) but agreement between 3DE and MRI was excellent (ICC = 0.88 and 0.87, respectively). Ejection fraction was 47.7 +/- 7.8 with 3DE and 47.9 +/- 6.7 with MRI, agreement between both methods was good (ICC = 0.72). Three-dimensional echocardiography combined to semi-automated quantification software shows fair agreement with MRI for RV volumes and EF measurement in patients with repaired ToF and adequate intra- and interobserver variability. These results suggest applicability for serial follow-up of patients with right heart congenital disease. However, the accuracy of 3DE echo diminishes with larger RV volumes, in part due to current difficulty to include the entire RV in the imaged sector. Technical progress in transducers beam geometry is likely to address this issue.

Left atrial volume measurement with automated border detection by 3-dimensional echocardiography: comparison with magnetic resonance imaging

ObjectiveLeft atrial size is an important marker for adverse cardiovascular events. There is general consensus that left atrial volume index (LAVI) is the best measurement of size. The current LAVI measurement techniques are laborious. Semi-automated measurement with a 3-dimensional echocardiography (3DE) system may be a practical clinical alternative to measure LAVI, but it has not been adequately evaluated against Magnetic Resonance Imaging (MRI) gold standard. The aim of this study was to compare the accuracy of a commercially available 3D algorithm for measurement of LAVI against LAVI obtained from MRI and Area Length Method (ALM).DesignIn 27 consecutive subjects referred for cardiac MRI (age 54 ± 13 years, 63% male), LAVI was measured using 3 imaging modalities: 3DE, ALM, MRI and the results were correlated. ALM was measured using standard American Society of Echocardiography guidelines. The time required to measure LAVI by 3DE and ALM were compared.ResultsThere was a significant correlation in systolic and diastolic LA volumes and left atrial ejection fraction between 3DE and MRI (r = 0.86 for systole, r = 0.76 for diastole, r = 0.88 for ejection fraction, P < 0.0001 for all). There was also significant correlation of diastolic volumes between 3DE and ALM (r = 0.77, P < 0.0001). The time to obtain LAVI was shorter using 3DE versus ALM (56 ± 8 vs 135 ± 55 seconds, P < 0.0001).ConclusionThree-dimensional echocardiography with semiautomatic border detection is a practical alternative for obtaining the left atrial volume in a time-efficient manner compared to the current standard.

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 (R2 > or = 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.

Real-time three-dimensional echocardiography in aortic stenosis: a novel, simple, and reliable method to improve accuracy in area calculation

The aim of the study was to validate a novel formula for aortic area, based on the principle of continuity equation (CE), that substitutes Doppler-derived stroke volume (SV) by SV directly measured with real-time three-dimensional (RT3D) echo and semi-automated border detection. RT3D has proved outstanding accuracy for left ventricular volume calculation. So far, however, neither this potential has been applied to haemodynamic assessment, nor RT3D has succeeded in the evaluation of aortic valve disease. Aortic area was measured in 41 patients with aortic stenosis using Gorlin's equation, Hakki's formula, Doppler CE, two-dimensional Simpson's volumetric method, and by the novel RT3D method. RT3D has the best linear association and absolute agreement with Gorlin of all non-invasive methods r = 0.902, intraclass correlation coefficient (ICC) = 0.846, better than CE (r = 0.646, ICC = 0.626) and two-dimensional volumetric method (r = 0.627, ICC = 0.378). Linear and Passing-Bablok regression show that RT3D fits better to Gorlin (r(2) = 0.814) than CE (r(2) = 0.417) and two-dimensional method (r(2) = 0.393). Its accuracy is comparable to Hakki's formula, routinely employed in catheter laboratories. Inter- and intraobserver agreements (ICC) were, respectively, 0.732 and 0.985, better than CE (0.662, 0.857). RT3D also grades most efficiently the severity of aortic stenosis as mild, moderate, or severe (weighted kappa = 0.932). RT3D underestimates aortic area (95% CI 0.084-0.193). ROC curves, however, show that the optimal cutoff point to consider aortic stenosis severity remains close to 1 cm(2) (1.06 cm(2)). RT3D is more accurate than CE and than two-dimensional volumetric methods to calculate area and to grade the severity of aortic stenosis. Area obtained by three-dimensional echo is slightly underestimated, but its range is clinically negligible.

Abstract 1961: Multi-Modality Comparison of Volumetric Quantification of Right Ventricular Volumes Using a Novel Semi-Automated Border Detection Software

Background. Right ventricular volumes (RVV) and ejection fraction (RVEF) measurements are challenging due to the complex shape of the right ventricle (RV). Current methods are tedious and have limited ability to take into account the base of the RV and right ventricular outflow tract. Novel semi-automated border detection software, RV analysis (RVA) was recently developed (TomTec) to overcome these limitations. Our goal was to determine whether there are inter-modality differences between real-time 3D echocardiographic (RT3DE), cardiac computed tomography (CCT) and cardiac magnetic resonance (CMR) data using the same RVA. Methods. We acquired transthoracic RT3DE images of the RV (Philips iE33 w/X4 probe) from the apical window using a full-volume mode in 12 patients referred for CMR imaging (1.5T Siemens scanner) and CCT (Toshiba) on the same day. CMR and CCT images were obtained in a stack of short-axis slices from RV base to apex, four-chamber and coronal views, and reformatted to obtain Cartesian volume data. All three types of images were analyzed to obtain end-systolic and end-diastolic volumes (ESV, EDV) and EF using RV analysis software (RVA). RT3DE and CCT were compared to CMR values as the reference standard, using linear regression and Bland-Altman analyses. Results. Analysis of RT3DE, CCT and CMR data were feasible in all patients. RT3DE and CCT RVV and RVEF correlated well with CMR (Table). CCT overestimated RVV whereas RT3DE underestimated RVV. Both CCT and RT3DE slightly underestimated RVEF compared to CMR. Conclusion. This new technique for volumetric RV surface detection applied to RT3DE and CCT data provides accurate RVV and RVEF measurements in agreement with CMR.