Cardiac Magnetic Resonance Reference Research Articles

Multiparametric Cardiac Magnetic Resonance Imaging to Discriminate Endomyocardial Biopsy-Proven Chronic Myocarditis From Healed Myocarditis

BackgroundDetecting ongoing inflammation in myocarditis patients has prognostic relevance, but there are limited data on the detection of chronic myocarditis and its differentiation from healed myocarditis. ObjectivesThis study sought to assess the performance of cardiac magnetic resonance (CMR) for the detection of ongoing inflammation and the discrimination of chronic myocarditis from healed myocarditis. MethodsConsecutive patients with persistent symptoms (>30 days) suggestive of myocarditis were prospectively enrolled from a single tertiary center. All patients underwent a multiparametric 1.5-T CMR protocol including biventricular strain, T1/T2 mapping, and late gadolinium enhancement (LGE). Endomyocardial biopsy was chosen for the reference standard diagnosis. ResultsAmong 452 consecutive patients, 103 (median age: 50 years; 66 men) had evaluable CMR and cardiopathologic reference diagnosis: 53 (51%) with chronic lymphocytic myocarditis and 50 (49%) with healed myocarditis. T2 mapping as a single parameter showed the best accuracy in detecting chronic myocarditis, if abnormal in ≥3 segments (92%; 95% CI: 85-97), and provided the best discrimination from healed myocarditis, as defined by the area under the receiver-operating characteristic curve (0.87 [95% CI: 0.79-0.93]; P < 0.001), followed by radial peak systolic strain rate of the left ventricle (0.86) and the right ventricle (0.84); T1 mapping (0.64), extracellular volume fraction (0.62), and LGE (0.57). Specificity increased when T2 mapping was combined with elevation of either troponin or C-reactive protein. ConclusionsA multiparametric CMR protocol allows detection of ongoing myocardial inflammation and discrimination of chronic myocarditis from healed myocarditis, with segmental T2 mapping and biventricular strain analysis showing higher diagnostic accuracy compared with T1 mapping, extracellular volume fraction, and LGE. The use of biomarkers (troponin or C-reactive protein) may improve specificity.

Three-Dimensional Echocardiographic Deconstruction: Feasibility of Clinical Evaluation from Two-Dimensional Views Derived from a Three-Dimensional Data Set

Three-dimensional echocardiography (3DE) makes it possible to capture the entire heart in a single data set that theoretically could be used to extract any two-dimensional (2D) views and potentially replace the standard practice of serial 2D acquisitions. The aim of this study was to test the hypothesis that the quality of 3DE-derived 2D images is sufficient to allow the visualization of the left ventricular (LV), right ventricular (RV), and left atrial (LA) endocardium, on par with images from conventional two-dimensional echocardiography (2DE), and potentially more accurate quantification of chamber size and function. First, the investigators prospectively studied 36 patients who underwent 2DE in 14 standard views, and full-volume data sets from 3DE, from which the same views were extracted offline. The ability to visualize the LV endocardium, RV free wall, and LA endocardium was scored. LV linear dimensions, LV volumes, and LV ejection fraction (LVEF), LA volume, and RV basal dimension were measured and compared between both types of images. Thereafter, 40 patients who underwent 2DE, 3DE, and cardiac magnetic resonance (CMR) imaging on the same day were retrospectively studied. LV volumes and LVEF derived from 2DE and 3DE were compared side by side against the CMR reference. Intertechnique agreement in visualization scores was 87% for LV segments, 86% for the RV free wall, and 83% for the LA endocardium. The correlations between 2DE- and 3DE-derived measurements were 0.95, 0.97, and 0.97 for LV volumes and LVEF, respectively, and 0.88 for RV basal dimension. Three-dimensional echocardiography-derived measurements of LV volumes and LVEF were more similar to those on CMR than those obtained on conventional 2DE. The feasibility of segmental assessment of cardiac chambers using 3DE-derived 2D views is similar to that using conventional 2DE. This approach provides similar quantitative information, including more accurate LV volumes and LVEF measurements compared with CMR, and thus promises to significantly shorten the duration of the echocardiographic examination.

Left Heart Chamber Volumetric Assessment by Automated Three-Dimensional Echocardiography in Heart Transplant Recipients.

BackgroundRecently, a new automated software (Heart Model) was developed to obtain three-dimensional (3D) left heart chamber volumes. The aim of this study was to verify the feasibility and accuracy of the automated 3D echocardiographic algorithm in heart transplant (HTx) patients. Conventional manual 3D transthoracic echocardiographic (TTE) tracings and cardiac magnetic resonance (CMR) images were used as a reference for comparison.MethodsThis study enrolled 103 healthy HTx patients prospectively. In protocol 1, left ventricular end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), left atrial max volume (LAVmax), LA minimum volume (LAVmin) and LV ejection fraction (LVEF) were obtained using the automated 3D echocardiography (3DE) and compared with corresponding values obtained through the manual 3DE. In protocol 2, 28 patients’ automated 3DE measurements were compared with CMR reference values. The impacts of contour edit and surgical technique were also tested.ResultsHeart Model was feasible in 97.1% of the data sets. In protocol 1, there was strong correlation between 3DE and manual 3DE for all the parameters (r = 0.77 to 0.96, p<0.01). Compared to values obtained through manual measurements, LV volumes and LVEF were overestimated by the automated algorithm and LA volumes were underestimated. All the biases were small except for that of LAVmin. After contour adjustment, the biases reduced and all the limits of agreement were clinically acceptable. In protocol 2, the correlations for LV and LA volumes were strong between automated 3DE with contour edit and CMR (r = 0.74 to 0.93, p<0.01) but correlation for LVEF remained moderate (r = 0.65, p < 0.01). Automated 3DE overestimated LV volumes but underestimated LVEF and LA volumes compared with CMR. The limits of agreement were clinically acceptable only for LVEDV and LAVmax.ConclusionSimultaneous quantification of left heart volumes and LVEF with the automated Heart Model program is rapid, feasible and to a great degree it is accurate in HTx recipients. Nevertheless, only LVEDV and LAVmax measured by automated 3DE with contour edit seem applicable for clinical practice when compared with CMR. Automated 3DE for HTx recipients is a worthy attempt, though further verification and optimization are needed.

Feasibility and Accuracy of a Fully Automated Right Ventricular Quantification Software With Three-Dimensional Echocardiography: Comparison With Cardiac Magnetic Resonance.

Background: A novel, fully automated right ventricular (RV) software for three-dimensional quantification of RV volumes and function was developed. The direct comparison of the software performance with cardiac magnetic resonance (CMR) was limited. Therefore, the aim of this study was to test the feasibility, accuracy, and reproducibility of a fully automated RV quantification software against CMR imaging as a reference.Methods: A total of 170 patients who underwent both CMR and three-dimensional echocardiography were enrolled. RV end-diastolic volume (RVEDV), RV end-systolic volume (RVESV), and RV ejection fraction (RVEF) were obtained using fully automated three-dimensional RV quantification software and compared with a CMR reference. For inter-technical agreement, Spearman correlation and Bland–Altman analysis were used.Results: The fully automated RV quantification software was feasible in 149 patients. RVEDV and RVESV were underestimated, and RVEF was overestimated compared with CMR values. RV measurements obtained from the manual editing method correlated better with CMR values than that without manual editing (RVEDV, 0.924 vs. 0.794: RVESV, 0.955 vs. 0.854; RVEF, 0.941 vs. 0.781 respectively, all p < 0.0001) with less bias and narrower limit of agreement (LOA). The bias and LOA for RV volumes and EF using the automated software without and with manual editing were greater in patients with severely impaired RV function or low frame rate than those with normal and mild impaired RV function, or high frame rate. The fully automated RV three-dimensional measurements were highly reproducible.Conclusion: The novel fully automated RV software shows good feasibility and reproducibility, and the measurements had a high correlation with CMR values. These findings support the routine application of the novel 3D automated RV software in clinical practice.

Real time three-dimensional echocardiographic quantification of left atrial volume in orthotopic heart transplant recipients: Comparisons with cardiac magnetic resonance imaging.

The accuracy of real time three-dimensional echocardiography (RT-3DE) in evaluating left atrial volume (LAV) of heart transplant recipients against cardiac magnetic resonance (CMR) has not been reported. The aim of this study was to compare LAV with RT-3DE with respect to CMR in heart transplant recipients. Thirty-one heart transplant recipients who received echocardiogram and CMR examination on the same day were prospectively enrolled. The maximal LAV, minimal LAV by RT-3DE, and two-dimensional echocardiography (2DE) were compared with CMR measurements. Inter-technique comparisons included Pearson's correlation coefficient and Bland-Altman analysis. Reproducibility of 2DE and RT-3DE technique was assessed by intra-class correlation coefficient (ICC). RT-3DE-derived LAV values showed higher correlation with CMR than 2DE measurements in heart transplant recipients (r=.93 vs r=.76 for maximal LAV; r=.91 vs r=.81 for minimal LAV). Two-dimensional echocardiography underestimated maximal LAV by 10±31mL and minimal LAV by 26±26mL. Although RT-3DE underestimated minimal LAV 15±19mL, no significant difference between RT-3DE and CMR was observed in maximal LAV (RT-3DE: 86±22mL; CMR: 89±23mL, P=.079), with a negligible bias of 3mL. Inter-observer and intra-observer agreement were excellent for 2DE and RT-3DE parameters. Compared with CMR reference, RT-3DE-derived LAV measurements are more accurate than 2DE-based analysis in heart transplant recipients, especially with regard to the assessment of maximal LAV. RT-3DE may be a valid alternative to CMR for quantification LAV in heart transplant recipients.

Development of novel machine learning model for right ventricular quantification on echocardiography-A multimodality validation study.

PurposeEchocardiography (echo) is widely used for right ventricular (RV) assessment. Current techniques for RV evaluation require additional imaging and manual analysis; machine learning (ML) approaches have the potential to provide efficient, fully automated quantification of RV function.MethodsAn automated ML model was developed to track the tricuspid annulus on echo using a convolutional neural network approach. The model was trained using 7791 image frames, and automated linear and circumferential indices quantifying annular displacement were generated. Automated indices were compared to an independent reference of cardiac magnetic resonance (CMR) defined RV dysfunction (RVEF < 50%).ResultsA total of 101 patients prospectively underwent echo and CMR: Fully automated annular tracking was uniformly successful; analyses entailed minimal processing time (<1 second for all) and no user editing. Findings demonstrate all automated annular shortening indices to be lower among patients with CMR‐quantified RV dysfunction (all P < .001). Magnitude of ML annular displacement decreased stepwise in relation to population‐based tertiles of TAPSE, with similar results when ML analyses were localized to the septal or lateral annulus (all P ≤ .001). Automated segmentation techniques provided good diagnostic performance (AUC 0.69–0.73) in relation to CMR reference and compared to conventional RV indices (TAPSE and S′) with high negative predictive value (NPV 84%–87% vs 83%–88%). Reproducibility was higher for ML algorithm as compared to manual segmentation with zero inter‐ and intra‐observer variability and ICC 1.0 (manual ICC: 0.87–0.91).ConclusionsThis study provides an initial validation of a deep learning system for RV assessment using automated tracking of the tricuspid annulus.

Machine Learning–Based Three-Dimensional Echocardiographic Quantification of Right Ventricular Size and Function: Validation Against Cardiac Magnetic Resonance

Three-dimensional echocardiography (3DE) allows accurate and reproducible measurements of right ventricular (RV) size and function. However, widespread implementation of 3DE in routine clinical practice is limited because the existing software packages are relatively time-consuming and skill demanding. The aim of this study was to test the accuracy and reproducibility of new machine learning- (ML-) based, fully automated software for three-dimensional quantification of RV size and function. Fifty-six unselected patients with a wide range of RV size and function and image quality, referred for clinically indicated cardiac magnetic resonance (CMR) imaging, underwent a transthoracic 3DE exam on the same day. End-systolic and end-diastolic RV volumes (ESV, EDV) and ejection fraction (EF) were measured using the ML-based algorithm and compared with CMR reference values using Bland-Altman and linear regression analyses. RV function quantification by echocardiography was feasible in all patients. The automatic approach was accurate in 32% patients with analysis time of 15±1seconds and 100% reproducible. Endocardial contour editing was necessary after the automated postprocessing in the remaining 68% patients, prolonging analysis time to 114±71seconds. With these minimal adjustments, RV volumes and EF measurements were accurate in comparison with CMR reference (biases: EDV, -25.6±21.1mL; ESV, -7.4±16mL; EF, -3.3%±5.2%) and showed excellent reproducibility reflected by coefficients of variation <7% and intraclass correlations ≥0.95 for all measurements. The new ML-based 3DE algorithm provided accurate and completely reproducible RV volume and EF measurements in one-third of unselected patients without any boundary editing. In the remaining patients, quick minimal editing resulted in reasonably accurate measurements with excellent reproducibility. This approach provides a promising solution for fast three-dimensional quantification of RV size and function.

Three-dimensional full automated software in the evaluation of the left ventricle function: from theory to clinical practice.

Left ventricular systolic function evaluation is an essential part of all transthoracic echocardiographic (TTE) studies. 3D echocardiography (3DE) is superior to 2D and is recommended as the method of choice. However, since it is time consuming and requires training, it is rarely performed. Different automatic analysis software tries to overcome these limitations but they need to be accurate and reproducible before they can be used clinically. The aim of this study was to test the accuracy and reproducibility of new 3D automatic quantitative software in everyday clinical practice. 69 patients referred to our Echo Lab for a clinically indicated echocardiographic examination were included. All patients underwent a full TTE with 3D image acquisition. Left ventricular volumes and ejection fraction (LVEF) were obtained using Heart Model software, and compared with conventional 3D volumetric data. Automated analysis was performed using three different sliders setting, with or without regional editing if necessary. 20 patients underwent a cardiac magnetic resonance (CMR) study the same day of the echo and automated measurements were also compared with a CMR reference. Intra- and inter-technique comparisons including linear regression with Pearson correlation coefficients and Bland-Altman analyses were calculated. Mean age of the patients was 59years, with 49.3% male. The automated 3DE model demonstrated excellent correlation with the conventional 3DE measurements of LVEF, using three different sliders settings (r = 0.906; r = 0.898 and r = 0.940). Correlations with CMR values were very good as well (r = 0.888; r = 0.869; r = 0.913). Similarly, no significant differences were noted between the values of EDV and ESV, measured with the automated model or CMR, with excellent correlation (EDV: r = 0.892, r = 0.842, 0.910; ESV: r = 0.925, r = 0.860, r = 0.907). Finally, volumes calculated with the automated software were significantly greater than those obtained manually, but they showed a very good correlation (EDV: r = 0.875, r = 0.856, r = 0.891; ESV: r = 0.929, r = 0.879, r = 949). 3D automatic software for LV quantification is feasible and shows excellent correlations with both CMR and 3D echocardiography, considered the gold standard. No clinically relevant differences were noted when applying different border settings. This technique holds promise to facilitate the integration of 3D TTE into clinical practice.

Transthoracic 3D Echocardiographic Left Heart Chamber Quantification Using an Automated Adaptive Analytics Algorithm

ObjectivesThe goal of this study was to test the feasibility and accuracy of an automated algorithm that simultaneously quantifies 3-dimensional (3D) transthoracic echocardiography (TTE)-derived left atrial (LA) and left ventricular (LV) volumes and left ventricular ejection fraction (LVEF). Conventional manual 3D TTE tracings and cardiac magnetic resonance (CMR) images were used as a reference for comparison. BackgroundCardiac chamber quantification from 3D TTE is superior to 2D TTE measurements. However, integration of 3D quantification into clinical practice has been limited by time-consuming workflow and the need for 3D expertise. A novel automated software was developed that provides LV and LA volumetric quantification from 3D TTE datasets that reflect real-life manual 3-dimensional echocardiography measurements and values comparable to CMR. MethodsA total of 159 patients were studied in 2 separate protocols. In protocol 1, 94 patients underwent 3D TTE imaging (EPIQ, iE33, X5-1, Philips Healthcare, Andover, Massachusetts) covering the left atrium and left ventricle. LA and LV volumes and LVEF were obtained using the automated software (HeartModel, Philips Healthcare) with and without contour correction, and compared with the averaged manual 3D volumetric measurements from 3 readers. In protocol 2, automated measurements from 65 patients were compared with a CMR reference. The Pearson correlation coefficient, Bland-Altman analysis, and paired Student t tests were used to assess inter-technique agreement. ResultsCorrelations between the automated and manual 3D TTE measurements were strong (r = 0.87 to 0.96). LVEF was underestimated and automated LV end-diastolic, LV end-systolic, and LA volumes were overestimated compared with manual measurements. Agreement between the automated analysis and CMR was also strong (r = 0.84 to 0.95). Test–retest variability was low. ConclusionsAutomated simultaneous quantification of LA and LV volumes and LVEF is feasible and requires minimal 3D software analysis training. The automated measurements are not only comparable to manual measurements but also to CMR. This technique is highly reproducible and timesaving, and it therefore promises to facilitate the integration of 3D TTE-based left-heart chamber quantification into clinical practice.

Right Ventricular Volumes and Systolic Function by Cardiac Magnetic Resonance and the Impact of Sex, Age, and Obesity in a Longitudinally Followed Cohort Free of Pulmonary and Cardiovascular Disease: The Framingham Heart Study.

Cardiac magnetic resonance is uniquely well suited for noninvasive imaging of the right ventricle. We sought to define normal cardiac magnetic resonance reference values and to identify the main determinants of right ventricular (RV) volumes and systolic function using a modern imaging sequence in a community-dwelling, longitudinally followed cohort free of clinical cardiovascular and pulmonary disease. The Framingham Heart Study Offspring cohort has been followed since 1971. We scanned 1794 Offspring cohort members using steady-state free precession cardiac magnetic resonance and identified a reference group of 1336 adults (64±9 years, 576 men) free of prevalent cardiovascular and pulmonary disease. RV trabeculations and papillary muscles were considered cavity volume. Men had greater RV volumes and cardiac output before and after indexation to body size (all P<0.001). Women had higher RV ejection fraction than men (68±6% versus 64±7%; P<0.0001). RV volumes and cardiac output decreased with advancing age. There was an increase in raw and height-indexed RV measurements with increasing body mass index, but this trend was weakly inverted after indexation of RV volumes to body surface area. Sex, age, height, body mass index, and heart rate account for most of the variability in RV volumes and function in this community-dwelling population. We report sex-specific normative values for RV measurements among principally middle-aged and older adults. RV ejection fraction is greater in women. RV volumes increase with body size, are greater in men, and are smaller in older people. Body surface area seems to be appropriate for indexation of cardiac magnetic resonance-derived RV volumes.

Determination of Right Ventricular Volume by Combining Echocardiographic Distance Measurements.

The position of the right ventricle (RV), often partly behind the sternum, implies difficulties to image the RV free wall using transthoracic echocardiography (TTE) and consequently limits the possibilities of stroke volume calculations. The aim of this study was to evaluate whether the volume of the right ventricle (RV) can be determined by combining TTE distance measurements that do not need the RV free wall to be fully visualized. The RV volume was approximated by an ellipsoid composed of three distances. Distance measurements, modeled RV stroke volumes (RVSV), and RV ejection fraction (RVEF) were compared to reference values obtained from cardiac magnetic resonance (CMR) imaging for 12 healthy volunteers. Inter-modality comparisons showed that distance measurements were significantly underestimated in TTE compared to CMR. The modeled RV volumes using TTE distance measurements were underestimated compared to reference CMR volumes. There was, however, for TTE an agreement between modeled RVSV and left ventricular stroke volumes determined by biplane Simpson's rule. Similar agreement was shown between modeled RVSV based on CMR distance measurements and the CMR reference. Regarding RVEF, further studies including patients with a wider range of RVEF are needed to evaluate the method. In conclusion, the ellipsoid model of the RV provides good estimates of RVSVs, but volumes based on distance measurements from different modalities cannot be used interchangeably.

Real-Time 3D Echocardiographic Quantification of Left Atrial Volume: Multicenter Study for Validation With CMR

We studied in a multicenter setting the accuracy and reproducibility of 3-dimensional echocardiography (3DE)-derived measurements of left atrial volume (LAV) using new, dedicated volumetric software, side by side with 2-dimensional echocardiography (2DE), using cardiac magnetic resonance (CMR) imaging as a reference. Increased LAV is associated with adverse cardiovascular outcomes. Although LAV measurements are routinely performed using 2DE, this methodology is limited because it is view dependent and relies on geometric assumptions regarding left atrial shape. Real-time 3DE is free of these limitations and accordingly is an attractive alternative for the evaluation of LAV. However, few studies have validated 3DE-derived LAV measurements against an accepted independent reference standard, such as CMR imaging. We studied 92 patients with a wide range of LAV who underwent CMR (1.5-T) and echocardiographic imaging on the same day. Images were analyzed to obtain maximal and minimal LAV: CMR images using standard commercial tools, 2DE images using a biplane area-length technique, and 3DE images using Tomtec LA Function software. Intertechnique comparisons included linear regression and Bland-Altman analyses. Reproducibility of all 3 techniques was assessed by calculating the percentage of absolute differences in blinded repeated measurements. Kappa statistics were used to compare 2DE and 3DE classification of normal/enlarged against the CMR reference. 3DE-derived LAV values showed higher correlation with CMR than 2DE measurements (r = 0.93 vs. r = 0.74 for maximal LAV; r = 0.88 vs. r = 0.82 for minimal LAV). Although 2DE underestimated maximal LAV by 31 ± 25 ml and minimal LAV by 16 ± 32 ml, 3DE resulted in a minimal bias of -1 ± 14 ml for maximal LAV and 0 ± 21 ml for minimal LAV. Interobserver and intraobserver variability of 2DE and 3DE measurements of maximal LAV were similar (7% to 12%) and approximately 2 times higher than CMR (4% to 5%). 3DE classified enlarged atria more accurately than 2DE (kappa: 0.88 vs. 0.71). Compared with CMR reference, 3DE-derived LAV measurements are more accurate than 2DE-based analysis, resulting in fewer patients with undetected atrial enlargement.

Ascending Aortic and Main Pulmonary Artery Areas Derived From Cardiovascular Magnetic Resonance as Reference Values for Normal Subjects and Repaired Tetralogy of Fallot

Cardiac magnetic resonance (CMR) imaging is an important clinical tool for serial follow-up of patients with congenital heart disease, but normative data for great vessel dimensions in pediatric subjects are scarce. We investigated the ascending aortic (AO) and main pulmonary artery dimensions in normal children and young adults in comparison with a cohort of patients with repaired tetralogy of Fallot (TOF). Subjects were prospectively enrolled for cardiac magnetic resonance after a standardized protocol in 14 participating centers of the German Competence Network for Congenital Heart Defects. All studies were performed in 1.5-T scanners and used single-slice multiphase acquisitions steady-state free precession and velocity-encoded cine. AO and main pulmonary artery areas were measured. The cohort consisted of 483 subjects: 105 normal controls (55 men; 50 women; and median age, 14 years) and 378 patients with repaired TOF (210 men; 168 women; and median age, 16 years). Among TOF, 35 (9%) had pulmonary atresia, 98 (26%) had a palliative procedure before repair, the mean age at repair was 2.9 years, and 82 (23%) used a transannular patch repair. Great vessel areas correlated well with body surface area and age in controls and reference Z-score values were derived. Z scores for ascending AO areas were larger in TOF compared with controls (mean Z score =1.95, P=0.001). In TOF, pulmonary atresia (P=0.003), male sex (P=0.01) and previous palliations (P=0.046) were associated with larger AO areas. Main pulmonary artery area Z scores in surgically modified TOF were smaller on an average than controls (mean Z score =-0.293 P=0.001) but not small to the same extent as the AO was large. This study provides cardiac magnetic resonance reference Z scores for great vessel areas in normal children and adolescents in comparison with a large contemporary cohort of repaired TOF. Male sex, pulmonary atresia, and previous palliations emerged as predictors for larger AO dimensions in TOF.

Assessment of Right Ventricular Function Using Echocardiographic Speckle Tracking of the Tricuspid Annular Motion: Comparison with Cardiac Magnetic Resonance

Assessment of right ventricular (RV) function is difficult due to the complex shape of this chamber. Tricuspid annular plane systolic excursion (TAPSE) measured with M-mode echocardiography is frequently used as an index of RV function. However, its accuracy may be limited by ultrasound beam misalignment. We hypothesized that two-dimensional (2D) speckle tracking echocardiography (STE) could provide more accurate estimates of RV function. Accordingly, STE was used to quantify tricuspid annular displacement (TAD), from which RV longitudinal shortening fraction (LSF) was calculated. These STE derived indices were compared side-by-side with M-mode TAPSE measurements against cardiac magnetic resonance (CMR) derived RV ejection fraction (EF). Echocardiography (Philips iE33, four-chamber view) and CMR (Siemens, 1.5 T) were performed on the same day in 63 patients with a wide range of RV EF (23-70% by CMR). TAPSE was measured using M-mode echocardiography. TAD and RV LSF were obtained using STE analysis (QLAB CMQ, Philips). TAPSE, TAD and RV LSF values were compared with RV EF obtained from CMR short axis stacks. STE analysis required <15 seconds and was able to track tricuspid annular motion in all patients as verified visually. Correlation between RV EF and TAD (0.61 free-wall, 0.65 septal) was similar to that with M-mode TAPSE (0.63). However, STE-derived RV LSF showed a higher correlation with CMR EF (r = 0.78). RV LSF measurement by STE is fast and easy to obtain and provides more accurate evaluation of RV EF than the traditional M-mode TAPSE technique, when compared to CMR reference. (Echocardiography 2012;29:19-24).

Clinical Value of Real-Time Three-Dimensional Echocardiography for Right Ventricular Quantification in Congenital Heart Disease: Validation With Cardiac Magnetic Resonance Imaging

The objective of this study was to test the feasibility, accuracy, and reproducibility of the assessment of right ventricular (RV) volumes and ejection fraction (EF) using real-time three-dimensional echocardiographic (RT3DE) imaging in patients with congenital heart disease (CHD), using cardiac magnetic resonance (CMR) as a reference. RT3DE data sets and short-axis cine CMR images were obtained in 62 consecutive patients (mean age, 26.9 +/- 10.4 years; 65% men) with various CHDs. RV volumetric quantification was done using semiautomated 3-dimensional border detection for RT3DE images and manual tracing of contours in multiple slices for CMR images. Adequate RV RT3DE data sets could be analyzed in 50 of 62 patients (81%). The time needed for RV acquisition and analysis was less for RT3DE imaging than for CMR (P < .001). Compared with CMR, RT3DE imaging underestimated RV end-diastolic and end-systolic volumes and EF by 34 +/- 65 mL, 11 +/- 55 mL, and 4 +/- 13% (P < .05) with 95% limits of agreement of +/-131 mL, +/-109 mL, and +/-27%, as shown by Bland-Altman analyses, with highly significant correlations (r = 0.93, r = 0.91, and r = 0.74, respectively, P < .001). Interobserver variability was 1 +/- 15%, 6 +/- 17%, and 8 +/- 13% for end-diastolic and end-systolic volumes and EF, respectively. In the majority of unselected patients with complex CHD, RT3DE imaging provides a fast and reproducible assessment of RV volumes and EF with fair to good accuracy compared with CMR reference data when using current commercially available hardware and software. Further studies are warranted to confirm our data in similar and other patient populations to establish its use in clinical practice.

Multimodality Comparison of Quantitative Volumetric Analysis of the Right Ventricle

We undertook volumetric analysis of the right ventricle (RV) by real-time 3-dimensional echocardiography (RT3DE), cardiac magnetic resonance (CMR), and cardiac computed tomography (CCT) on images obtained in RV-shaped phantoms and in patients with a wide range of RV geometry. Assessment of the RV by 2-dimensional (2D) echocardiography remains challenging due to its unique geometry and limitations of the current analysis techniques. RT3DE, CMR, and CCT, which can quantify RV volumes, promise to overcome the limitations of 2D echocardiography. Images were analyzed using RV Analysis software. Volumes measured in vitro were compared with the true volumes. The human protocol included 28 patients who underwent RT3DE, CMR, and CT on the same day. Volumetric analysis of CMR images was used as a reference, against which RT3DE and CCT measurements were compared using linear regression and Bland-Altman analyses. To determine the reproducibility of the volumetric analysis, repeated measurements were performed for all 3 imaging modalities in 11 patients. The in vitro measurements showed that: 1) volumetric analysis of CMR images yielded the most accurate measurements; 2) CCT measurements showed slight (4%) but consistent overestimation; and 3) RT3DE measurements showed small underestimation, but considerably wider margins of error. In humans, both RT3DE and CCT measurements correlated highly with the CMR reference (r=0.79 to 0.89) and showed the same trends of underestimation and overestimation noted in vitro. All interobserver and intraobserver variability values were <14%, with those of CMR being the highest. Volumetric quantification of RV volume was performed on CMR, CCT, and RT3DE images. Eliminating analysis-related intermodality differences allowed fair comparisons and highlighted the unique limitations of each modality. Understanding these differences promises to aid in the functional assessment of the RV.

Real-Time 3-Dimensional Echocardiography

One of the most significant developments of the last decade in ultrasound imaging of the heart was the evolution of 3-dimensional (3D) imaging from slow and labor-intense offline reconstruction to real-time volumetric imaging. This imaging modality provides valuable clinical information that empowers echocardiographers with new levels of confidence in the diagnosis of heart disease. We have previously described the technological milestones in the development of real-time 3D echocardiographic (RT3DE) imaging and its major advantages over conventional 2-dimensional echocardiography (2DE) and reviewed the published literature that supported the use of this new methodology in clinical practice.1 Since 2006, the growing availability of RT3DE technology, its ease of use, and its multiple attractive features have sparked significant interest in the research community, resulting in a large number of publications, most of which have endorsed RT3DE imaging for clinical use by demonstrating its unique capabilities in different scenarios. In parallel, the clinical acceptance of this new tool has broadened significantly. The most recent clinically significant addition is matrix-array transesophageal echocardiography (TEE), which provides images of unprecedented quality that aid surgeons and interventional cardiologists in planning and guiding procedures and evaluating their outcomes. The purpose of the present article is to review the most recent RT3DE literature and provide readers with an update on the latest developments and the current status of this noninvasive imaging tool. Because different potential applications of RT3DE imaging have been explored to various extents, they are described here separately, and each is discussed with an emphasis on the scientifically established facts, along with the known stumbling blocks and difficulties. A firmly established advantage of 3D imaging over cross-sectional slices of the heart is the improvement in the accuracy of the evaluation of left ventricular (LV) volumes and ejection fraction (EF) by eliminating the need for geometric modeling, which …

Real-Time 3-Dimensional Echocardiographic Quantification of Left Ventricular Volumes: Multicenter Study for Validation With Magnetic Resonance Imaging and Investigation of Sources of Error

We sought to study: 1) the accuracy and reproducibility of real-time 3-dimensional echocardiographic (RT3DE) analysis of left ventricular (LV) volumes in a multicenter setting, 2) interinstitutional differences in relationship with the investigators' specific experience, and 3) potential sources of volume underestimation. Reproducibility and accuracy of RT3DE evaluation of LV volumes has not been validated in multicenter studies, and LV volumes have been reported to be underestimated compared to cardiac magnetic resonance (CMR) standard. A total of 92 patients with a wide range of ejection fractions underwent CMR and RT3DE imaging at 4 different institutions. Images were analyzed to obtain LV end-systolic volume (ESV) and end-diastolic volume (EDV). Reproducibility was assessed using repeated analyses. The investigation of potential sources of error included: phantom imaging, intermodality analysis-related differences, and differences in LV boundary identification, such as inclusion of endocardial trabeculae and mitral valve plane in the LV volume. The RT3DE-derived LV volumes correlated highly with CMR values (EDV: r = 0.91; ESV: r = 0.93), but were 26% and 29% lower consistently across institutions, with the magnitude of the bias being inversely related to the level of experience. The RT3DE measurements were less reproducible (4% to 13%) than CMR measurements (4% to 7%). Minimal changes in endocardial surface position (1 mm) resulted in significant differences in measured volumes (11%). Exclusion of trabeculae and mitral valve plane from the CMR reference eliminated the intermodality bias. The RT3DE-derived LV volumes are underestimated in most patients because RT3DE imaging cannot differentiate between the myocardium and trabeculae. To minimize this difference, tracing the endocardium to include trabeculae in the LV cavity is recommended. With the understanding of these intermodality differences, RT3DE quantification of LV volume is a reliable tool that provides clinically useful information.

Dual Triggering Improves the Accuracy of Left Ventricular Volume Measurements by Contrast-enhanced Real-time 3-Dimensional Echocardiography

Real-time 3-dimensional echocardiographic continuous imaging (CIM) with contrast underestimates left ventricular (LV) volumes. We studied the effects of dual-triggered (DT) acquisition on the accuracy of LV volume measurements for patients with poor acoustic windows. Real-time 3-dimensional echocardiographic imaging was performed in 20 patients during LV opacification (Definity) on the same day as cardiac magnetic resonance imaging. Both CIM and DT data were analyzed using custom software to calculate end-systolic volume (ESV) and end-diastolic volume (EDV), which were compared with the cardiac magnetic resonance reference. CIM correlated well with the cardiac magnetic resonance reference (EDV: r = 0.89; ESV: r = 0.93), but underestimated EDV and ESV by 17% and 19%, respectively. In contrast, DT resulted in higher correlation (EDV: r = 0.95; ESV: r = 0.96) and smaller biases (9% and 6%, respectively). In conclusion, because the accuracy of LV volume measurements depends on the acquisition strategy of contrast-enhanced real-time 3-dimensional echocardiographic images, the use of DT instead of the conventional CIM acquisition is recommended.

Evaluation of New Software for Angiographic Determination of Right Ventricular Volumes

The scope of the study was to evaluate a recent software for angiographic volume determination as compared to cardiovascular magnetic resonance imaging. A new right ventricular analysis software closes a diagnostic gap in quantitative angiography. Cardiovascular magnetic resonance imaging short axis multi slice summation is a validated reference standard. Right ventricular angiograms were acquired in frontal and lateral projection in 15 pediatric and 17 adult patients. Additional angiograms were acquired in RAO30 degrees /LAO60 degrees projections in 10 adult patients. The tested models comprised area length with different regressions, multi-slice with different regressions, Boak, and pyramid method. Original regressions were used to calculate angiographic right ventricular volume. Right ventricular reference volumes were determined by multi-slice summation from cardiac magnetic resonance short-axis images. Mean inter-observer difference was -1 ml (95% confidence: -35-34 ml) and mean intra-observer difference was 0 ml (95% confidence: -22-22 ml). There was no significant difference (4 ml, 95% confidence: -22-30 ml) between geometric calibration and calibration by a sphere. The area length and multi-slice models demonstrated the best agreement with the cardiac magnetic resonance reference. Performance was best for the Onnasch Lange models. The evaluated software provides acceptably accurate volume estimates for the majority of ventricles. In a few cases larger errors may occur, however. The area length and multi-slice models preferably with Onnasch Lange regressions may be recommended. Inter- and intra-observer agreement were excellent. Geometric calibration using data from DICOM header files may be used.