Knowledge-based Reconstruction Research Articles

Value of echocardiography using knowledge-based reconstruction in determining right ventricular volumes in pulmonary sarcoidosis: comparison with cardiac magnetic resonance imaging

Abstract Background Right ventricular (RV) dysfunction in sarcoidosis is associated with adverse outcomes. Assessment of RV function by conventional transthoracic echocardiography (TTE) is challenging due to the complex RV geometry. Knowledge-based reconstruction (KBR) combines TTE measurements with three-dimensional coordinates to determine RV volumes. Purpose The aim of this study was to investigate the accuracy of TTE-KBR compared to the gold standard cardiac magnetic resonance imaging (CMR) in determining RV dimensions in pulmonary sarcoidosis. Methods Pulmonary sarcoidosis patients prospectively received same-day TTE and TTE-KBR. If performed, CMR within three months after TTE-KBR was used as reference standard. Outcome parameters included RV end-diastolic volume (RVEDV), end-systolic volume (RVESV), stroke volume (RVSV) and ejection fraction (RVEF). Results 282 patients underwent same day TTE and TTE-KBR. In total, 122 patients received a CMR within 90 days of TTE and were included. TTE-KBR measured RVEDV and RVESV showed strong correlation with CMR measurements (R=0.73, R=0.76), while RVSV and RVEF correlated weakly (R=0.46, R=0.46). Bland-Altman analyses (mean bias ±95% limits of agreement), showed good agreement for RVEDV (ΔRVEDVKBR-CMR, 5.67±55.4mL), while RVESV, RVSV and RVEF showed poor agreement (ΔRVESVKBR-CMR, 21.6±34.1mL; ΔRVSVKBR-CMR, −16.1±42.9mL; ΔRVEFKBR-CMR, −12.9±16.4%). Image quality, time to CMR and learning curve showed no impact. Conclusions TTE-KBR is convenient and shows good agreement with CMR for RVEDV. However, there is poor agreement for RVESV, RVSV and RVEF. The use of TTE-KBR does not seem to provide additional value in the determination of RV dimensions in pulmonary sarcoidosis patients. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): ZonMW (The Netherlands Organisation for Health Research and Development) Figure 1. Correlation plotsFigure 2. Bland-Altman plots

Value of echocardiography using knowledge-based reconstruction in determining right ventricular volumes in pulmonary sarcoidosis: comparison with cardiac magnetic resonance imaging.

Right ventricular (RV) dysfunction in sarcoidosis is associated with adverse outcomes. Assessment of RV function by conventional transthoracic echocardiography (TTE) is challenging due to the complex RV geometry. Knowledge-based reconstruction (KBR) combines TTE measurements with three-dimensional coordinates to determine RV volumes. The aim of this study was to investigate the accuracy of TTE-KBR compared to the gold standard cardiac magnetic resonance imaging (CMR) in determining RV dimensions in pulmonary sarcoidosis. Pulmonary sarcoidosis patients prospectively received same-day TTE and TTE-KBR. If performed, CMR within 90 days after TTE-KBR was used as reference standard. Outcome parameters included RV end-diastolic volume (RVEDV), end-systolic volume (RVESV), stroke volume (RVSV) and ejection fraction (RVEF). 281 patients underwent same day TTE and TTE-KBR. In total, 122 patients received a CMR within 90 daysof TTE and were included. TTE-KBR measured RVEDV and RVESV showed strong correlation with CMR measurements (R = 0.73, R = 0.76), while RVSV and RVEF correlated weakly (R = 0.46, R = 0.46). Bland-Altman analyses (mean bias ± 95% limits of agreement), showed good agreement for RVEDV (ΔRVEDVKBR-CMR, 5.67 ± 55.4mL), while RVESV, RVSV and RVEF showed poor agreement (ΔRVESVKBR-CMR, 21.6 ± 34.1mL; ΔRVSVKBR-CMR, -16.1 ± 42.9mL; ΔRVEFKBR-CMR, -12.9 ± 16.4%). The image quality and time between CMR and TTE-KBR showed no impact on intermodality differences and there was no sign of a possible learning curve. TTE-KBR is convenient and shows good agreement with CMR for RVEDV. However, there is poor agreement for RVESV, RVSV and RVEF. The use of TTE-KBR does not seem to provide additional value in the determination of RV dimensions in pulmonary sarcoidosis patients.

Real-time 3D-echocardiography of the right ventricle-paediatric reference values for right ventricular volumes using knowledge-based reconstruction: a multicentre study.

Real-time 3D echocardiography is a promising method for non-invasive assessment of right ventricular performance in children with congenital heart disease. Volume quantification using knowledge-based reconstruction (KBR) enables the calculation of right ventricular dimensions by matching endocardial landmarks with a reference library of right ventricular shapes. However, paediatric reference values for volumes based on KBR are missing. Aim of this study was to establish reference values for right ventricular volumes in a large paediatric population using 3D echocardiography and KBR. In a multicentre prospective-design study, 545 healthy children and adolescents (age range, 1 day to 216 months) underwent 3D echocardiography of the right ventricle using two different vendors (iE33, Philips or Vivid 7, GE). Volume analysis was performed by a semiautomatic quantification software (VMS, Ventripoint Diagnostics Ltd., Washington, US). Reference centiles were computed using Cole's LMS method and the gamlss package in R. For vendor comparison, 3D datasets were recorded subsequently in 20 subjects using both ultrasound devices. 3D datasets of 406/545 (74.5%) subjects provided an adequate image quality. Right ventricular volumes had a significant association with age, body size and sex. We created sex-specific percentiles indexed to body surface area (BSA). Intra- and interobserver-variation for all volume calculations were excellent with intraclass correlation coefficients (ICCs) between 0.973-0.998. Agreement of both vendors showed slightly higher end-diastolic and stroke volumes (bias ± standard deviation 2.2%±6.8% respectively 4.5%±8.1%) and smaller end-systolic volumes (-0.9±10.3%) using Philips datasets. Calculation of ventricular volumes by KBR allows reliable non-invasive assessment of right ventricular volumes with excellent intra- and interobserver variations. The calculated percentiles based on a large paediatric population serve as a reference and may facilitate the use of real-time 3D echocardiography for the analysis of right ventricular size and function.

Knowledge-based reconstruction for measurement of right ventricular volumes on cardiovascular magnetic resonance images in a mixed population.

Follow-up of right ventricular performance is important for patients with congenital heart disease. Cardiac magnetic resonance imaging is optimal for this purpose. However, observer-dependency of manual analysis of right ventricular volumes limit its use. Knowledge-based reconstruction is a new semiautomatic analysis tool that uses a database including knowledge of right ventricular shape in various congenital heart diseases. We evaluated whether knowledge-based reconstruction is a good alternative for conventional analysis. To assess the inter- and intra-observer variability and agreement of knowledge-based versus conventional analysis of magnetic resonance right ventricular volumes, analysis was done by two observers in a mixed group of 22 patients with congenital heart disease affecting right ventricular loading conditions (dextro-transposition of the great arteries and right ventricle to pulmonary artery conduit) and a group of 17 healthy children. We used Bland-Altman analysis and coefficient of variation. Comparison between the conventional method and the knowledge-based method showed a systematically higher volume for the latter group. We found an overestimation for end-diastolic volume (bias -40 ± 24 mL, r = .956), end-systolic volume (bias -34 ± 24 mL, r = .943), stroke volume (bias -6 ± 17 mL, r = .735) and an underestimation of ejection fraction (bias 7 ± 7%, r = .671) by knowledge-based reconstruction. The intra-observer variability of knowledge-based reconstruction varied with a coefficient of variation of 9% for end-diastolic volume and 22% for stroke volume. The same trend was noted for inter-observer variability. A systematic difference (overestimation) was noted for right ventricular size as assessed with knowledge-based reconstruction compared with conventional methods for analysis. Observer variability for the new method was comparable to what has been reported for the right ventricle in children and congenital heart disease with conventional analysis.

Two-dimensional knowledge-based volumetric reconstruction of the right ventricle documents short-term improvement in pulmonary hypertension.

Data are scarce about short-term right ventricular changes in pulmonary hypertension. Two-dimensional knowledge-based reconstruction of the right ventricle with 2D echocardiography (2DKBR) has been shown to be a valid alternative to Cardiac MRI. In this longitudinal study 25 pulmonary hypertension patients underwent 2DKBR of the right ventricle, assessment of NT-proBNP levels and functional class at baseline and after a mean follow-up of 6.1months. Patients were followed up clinically for a further mean of 8.2months. The majority of patients had connective tissue disease (CTD) associated pulmonary arterial hypertension (n=15) or chronic thromboembolic pulmonary hypertension (CTEPH; n=6). A total of 15 patients underwent an intervention, either new targeted therapy, escalation of targeted therapy or pulmonary endarterectomy. A total of 10 clinically stable patients were routinely followed up without any change in therapy. There were significant improvements in the right ventricular end-diastolic volume index (111±29mL/m² vs 100±36mL/m²; P=.038), end-systolic volume index (72±23mL/m² vs 61±25mL/m²; P=.001), and ejection fraction (35±10% vs 40±9%; P=.030). Changes in NT-proBNP levels correlated strongest with changes in end-systolic volume index (r=-.77; P=<.0001). Four patients experienced clinical worsening during extended follow-up, dilatation of the right ventricle was associated with clinical worsening. In a CTD and CTEPH dominated patient population significant reverse remodeling and improvement of ejection fraction occurred despite a short follow-up and was paralleled by significant changes in NT-proBNP levels. Further right ventricular dilatation was associated with worse clinical outcome. 2DKBR is a feasible substitute for Cardiac MRI to follow-up right ventricular indices in pulmonary hypertension.

22 Single centre experience of incorporating knowledge-based reconstruction for right ventricular volumetry into clinical practice

Knowledge-based reconstruction (KBR) is a new technique for calculating the volume of cardiac chambers accurately. The technique can be applied to 3D datasets (eg, MRI scans), but can also be used with conventional 2D echocardiography by tracking the probe position and orientation in 3D space. It is particularly useful for assessing the volume of the right ventricle without having to undergo an MRI scan. We acquired a KBR system in March 2015, and have been putting it into practice. We have performed 69 studies in 45 patients over an 18 month period, ages between 5 and 70 years average 18.9 years, 28 patients (62%) were between 5–12 years and 37 patients (82%) were below 18 years of age. Indications mainly for post surgical Tetralogy of Fallot variants or post pulmonary valve dilation resulting in free pulmonary regurgitation or mixed valve disease with resulting significant right ventricular volume loading . In a subset we have performed analysis on 13 patients who underwent pulmonary valve replacement, giving pre- and post- surgical RV volume and function analysis, all 13 patients had Cardiac MRI pre surgery, that was comparable to the pre-surgical KBR analysis. Conclusion Knowledge based reconstruction of right and left ventricle volumetric data can be preformed with good reliability and good alternative to MRI.

Trifecta St. Jude medical® aortic valve in pulmonary position

ABSTRACTIntroduction: To evaluate an aortic pericardial valve for pulmonary valve (PV) regurgitation after repair of congenital heart defects.Methods: From July 2012 to June 2016 71 patients, mean age 24 ± 13 years (four to years) underwent PV implantation of aortic pericardial valve, mean interval after previous repair = 21 ± 10 years (two to 47 years). Previous surgery at mean age 3.2 ± 7.2 years (one day to 49 years): tetralogy of Fallot repair in 83% (59/71), pulmonary valvotomy in 11% (8/71), relief of right ventricular outflow tract (RVOT) obstruction in 6% (4/71). Pre-operative echocardiography and MRI showed severe PV regurgitation in 97% (69/71), moderate in 3% (2/71) with associated RVOT obstruction. MRI and knowledge-based reconstruction 3D volumetry (KBR-3D-volumetry) showed mean PV regurgitation = 42 ± 9% (20–58%), mean indexed RV end-diastolic volume = 169 ± 33 (130–265) ml m–2 BSA and mean ejection fraction (EF) = 46 ± 8% (33–61%). Cardio-pulmonary exercise showed mean peak O2/uptake = 24 ± 8 ml kg–1 min–1 (14–45 ml kg–1 min–1), predicted max O2/uptake 66 ± 17% (26–97%). Pre-operative NYHA class was I in 17% (12/71) patients, II in 70% (50/71) and III in 13% (9/71).Results: Mean cardio-pulmonary bypass duration was 95 ± 30ʹ (38–190ʹ), mean aortic cross-clamp in 23% (16/71) 46 ± 31ʹ (8–95ʹ), with 77% (55/71) implantations without aortic cross-clamp. Size of implanted PV: 21 mm in seven patients, 23 mm in 33, 25 mm in 23, and 27 mm in eight. The z-score of the implanted PV was −0.16 ± 0.80 (−1.6 to 2.5), effective orifice area indexed (for BSA) of native PV was 1.5 ± 0.2 (1.2 to –2.1) vs. implanted PV 1.2 ± 0.3 (0.76 to –2.5) (p = ns). In 76% (54/71) patients surgical RV modelling was associated. Mean duration of mechanical ventilation was 6 ± 5 h (0–26 h), mean ICU stay 21 ± 11 h (12–64 h), mean hospital stay 6 ± 3 days (three to 19 days). In mean follow-up = 25 ± 14 months (six to 53 months) there were no early/late deaths, no need for cardiac intervention/re-operation, no valve-related complications, thrombosis or endocarditis. Last echocardiography showed absent PV regurgitation in 87.3% (62/71) patients, trivial/mild degree in 11.3% (8/71), moderate degree in 1.45% (1/71), mean max peak velocity through RVOT 1.6 ± 0.4 (1.0–2.4) m s–1. Mean indexed RV end-diastolic volume at MRI/KBR-3D-volumetry was 96 ± 20 (63–151) ml m–2 BSA, lower than pre-operatively (p < 0.001), and mean EF = 55 ± 4% (49–61%), higher than pre-operatively (p < 0.05). Almost all patients (99% = 70/71) remain in NYHA class I, 1.45% = 1/71 in class II.Conclusion: (a) Aortic pericardial valve is implantable in PV position with an easy and reproducible surgical technique; (b) valve size adequate for patient BSA can be implanted with simultaneous RV remodelling; (c) medium-term outcomes are good with maintained PV function, RV dimensions significantly reduced and EF significantly improved; (d) adequate valve size will allow later percutaneous valve-in-valve implantation.

Knowledge-based 3D reconstruction of the right ventricle: comparison with cardiac magnetic resonance in adults with congenital heart disease.

AimAssessment of right ventricular (RV) function is a challenge, especially in patients with congenital heart disease (CHD). The aim of the present study is to assess whether knowledge-based RV reconstruction, used in the everyday practice of an echo-lab for adult CHD in a tertiary referral center, is accurate when compared to cardiac magnetic resonance (CMR) examination.Subjects and methodsAdult patients who would undergo CMR for assessment of the RV were asked to undergo an echo of the heart for further knowledge-based reconstruction (KBR). Echocardiographic images were acquired in standard views using a predefined imaging protocol. RV volumes and ejection fraction (EF) calculated using knowledge-based technology were compared with the CMR data of the same patient.ResultsNineteen consecutive patients with congenital right heart disease were studied. Median age of the patients was 28 years (range 46 years). Reconstruction was possible in 16 out of 19 patients (85%). RV volumes assessed with this new method were smaller than with CMR. Indexed end diastolic volumes were 114±17 ml vs 121±19 ml, P<0.05 and EFs were 45±8% vs 47±9%, P<0.05 respectively. The correlation between the methods was good with an intraclass correlation of 0.84 for EDV and 0.89 for EF, P value <0.001 in both cases.ConclusionKBR enables reliable measurement of RVs in patients with CHDs and can be used in clinical practice for analysis of volumes and EFs.

Accuracy and Test-Retest Reproducibility of Two-Dimensional Knowledge-Based Volumetric Reconstruction of the Right Ventricle in Pulmonary Hypertension.

BackgroundRight heart function is the key determinant of symptoms and prognosis in pulmonary hypertension (PH), but the right ventricle has a complex geometry that is challenging to quantify by two-dimensional (2D) echocardiography. A novel 2D echocardiographic technique for right ventricular (RV) quantitation involves knowledge-based reconstruction (KBR), a hybrid of 2D echocardiography–acquired coordinates localized in three-dimensional space and connected by reference to a disease-specific RV shape library. The aim of this study was to determine the accuracy of 2D KBR against cardiac magnetic resonance imaging in PH and the test-retest reproducibility of both conventional 2D echocardiographic RV fractional area change (FAC) and 2D KBR.MethodsTwenty-eight patients with PH underwent same-day echocardiography and cardiac magnetic resonance imaging. Two operators performed serial RV FAC and 2D KBR acquisition and postprocessing to assess inter- and intraobserver test-retest reproducibility.ResultsBland-Altman analysis (mean bias ± 95% limits of agreement) showed good agreement for end-diastolic volume (3.5 ± 25.0 mL), end-systolic volume (0.9 ± 19.9 mL), stroke volume (2.6 ± 23.1 mL), and ejection fraction (0.4 ± 10.2%) measured by 2D KBR and cardiac magnetic resonance imaging. There were no significant interobserver or intraobserver test-retest differences for 2D KBR RV metrics, with acceptable limits of agreement (interobserver end-diastolic volume, −0.9 ± 21.8 mL; end-systolic volume, −1.3 ± 25.8 mL; stroke volume, −0.2 ± 24.2 mL; ejection fraction, 0.7 ± 14.4%). Significant test-retest variability was observed for 2D echocardiographic RV areas and FAC.ConclusionsTwo-dimensional KBR is an accurate, novel technique for RV volumetric quantification in PH, with superior test-retest reproducibility compared with conventional 2D echocardiographic RV FAC.

Knowledge-based iterative reconstruction technique: effect of different reconstruction settings on noise reduction and image quality in hepatic contrast-enhanced CT at different radiation dose levels

Objective To evaluate the effects of different reconstruction settings of knowledge-based iterative reconstruction technique (IMR) on noise reduction and image quality in hepatic contrast-enhanced CT(CECT) at different radiation dose levels. Methods Patients who underwent hepatic CECT because of their diseases were enrolled in this prospective study. According to random number table, patients were randomly assigned to two groups (standard dose group, SD-group, n=29; low dose group, LD-group, n=25).All patients underwent both non-enhanced CT and triphasic CECT scan including hepatic arterial phase (HAP), portal-venous phase (PVP) and delayed phase. PVP images of SD-group were acquired with tube voltage of 120 kVp and tube current-time products of 250 mAs, and 80 kVp and 500 mAs for LD-group. PVP images were reconstructed with both filtered back projection (FBP) and IMR techniques. Settings applied in IMR reconstructions consisted of body routine (BR) and body soft tissue (BST) with three levels (L1 to L3), and image series included: L1BR, L2BR, L3BR, L1BST, L2BST and L3BST. Subjective assessment of image quality including low contrast detectability (LCD), image distortion (ID) and diagnostic confidence (DC) as well as objective image quality including image noise, signal to noise ratio (SNR) and contrast to noise ratio (CNR) were compared between groups. Effective radiation dose was recorded. Objective image quality and subjective image quality were compared by using Friedman H test and ANOVA, respectively. In addition, Student t test was used to compare effective radiation doses between groups. Results In SD-group, IMR settings of L2BST, L3BST scored highest in LCD with median score of 4; L3BST and L2BST scored lowest in ID with median score of 3, while FBP and L1BR scored highest with median score of 4; L1BR, L2BR and L1BST scored highest in DC with median score of 4, while L3BST scored lowest with median score of 3. In LD-group, the distribution of all reconstruction settings scores in LCD and ID were similar to those in SD-group; however, L1BST scored highest with median score of 4, and FBP scored lowest with median score of 2 in DC. There were statistical differences in LCD, ID and DC among all the reconstruction settings for both groups (P<0.05). In terms of FBP technique, the image noise, SNR and CNR were (9.8±2.0)HU, 13.3±3.3 and 6.0±1.9 in SD-group, and (16.2±4.1)HU, 12.9±3.3 and 6.6± 2.3 in LD-group, respectively. In SD-group, image noise exhibited a trend of decrease from L1BR to L3BST[from (4.5±0.9) HU to (3.2±0.2)HU], while SNR, CNR trended to increase (SNR: from 21.4±1.4 to 24.6±4.6; CNR: from 9.4±2.2 to 10.9±2.9, respectively). The image noise, SNR and CNR in LD-group showed the same trends as SD-group [image noise: from (5.8±0.2)HU to (3.9±0.6)HU; SNR: from 26.3±4.5 to 33.1±6.9; CNR: from 13.6±4.0 to 17.4±5.1, respectively]. In both groups, there were statistically differences in image noise, SNR and CNR among all IMR settings and FBP (F values were 15.50 to 131.39, P<0.01). The effective radiation dose of the LD-group was significantly lower than that of the SD-group [(4.19±0.22) versus (7.32±0.58) mSv, t=15.27, P<0.01). Conclusions IMR can reduce image noise and improve image quality in hepatic CECT at both standard and low dose levels. L1BR, L2BR and L1BST are the most optimized reconstruction settings for the standard dose protocol, while L1BST performs best for the low dose protocol. Key words: Liver; Tomography, X-ray computed; Radiation dosage

Right Ventricular Assessment in Adult Congenital Heart Disease Patients with Right Ventricle–to–Pulmonary Artery Conduits

There is little data on right ventricular (RV) remodeling patterns in complex congenital heart disease (CHD) patients with right ventricle to pulmonary artery (PA) conduits, and novel RV imaging modalities have not been explored in this population. Knowledge of the RV remodeling process is an important first step to future understanding and tracking of the RV response to pressure and volume overload in this diverse population. Three-dimensional knowledge-based reconstruction (3DKBR) derived from two-dimensional transthoracic echocardiography (TTE-3DKBR) is a novel approach to RV assessment. The aims of this study were twofold: (1) to assess the feasibility and accuracy of 3DKBR in patients with CHD with RV to PA conduits and (2) to characterize the three-dimensional shape of the RV across the spectrum of CHD with RV to PA conduits. Seventeen patients with tetralogy of Fallot, pulmonary atresia with ventricular septal defect, or truncus arteriosus (mean age, 29±8years; 24% women) and a conduit referred for cardiac magnetic resonance imaging (CMR) were prospectively recruited and underwent TTE-3DKBR. TTE-3DKBR echocardiographic image acquisition was performed using a standard ultrasound scanner linked to a Ventripoint Medical Systems unit. The surface RV volumetric reconstruction was performed by transmitting two-dimensional data points to an online database and comparing these with a lesion-specific catalog to derive the RV reconstruction. Parameters analyzed were end-diastolic volume (EDV), end-systolic volume, and ejection fraction. Intertechnique agreement was assessed using Pearson's correlation analysis, coefficients of variation, and Bland-Altman analysis. Three-dimensional shape comparisons of RV surface reconstructions were performed via automated validation testing of CMRs from 43 patients (mean age, 30±8years; 32% women) with RV to PA conduits (tetralogy of Fallot, n=15; pulmonary atresia, n=19; and truncus arteriosus, n=9) distinct from patients in the 3DKBR comparison. There was good correlation and agreement between the two modalities: EDV, R=0.77, P=.0004; end-systolic volume, R=0.93, P<.0001; ejection fraction, R=0.75, P<.0005. On Bland-Altman analyses, CMR EDV was slightly larger TTE-3DKBR, while EF was slightly higher by 3DKBR. Qualitative and quantitative assessment both demonstrated RV shape diversity based on surface reconstructions. This study demonstrates that TTE-3DKBR is an alternative technology that can be used to assess the RV in patients with complex CHD with a conduit. A novel method was used to compare RV shapes in this important population, and our results draw specific attention to the fact that the RV both within and outside diagnostic groups has very different unpredictable shapes and should not be treated equally. Our findings should set into motion future work focused on indices of RV shape and their impact on overall RV function and clinical outcomes, hence defining optimal timing of conduit revision, which at the current time is very unclear.

0523: Feasibility and accuracy of left ventricular volumes and ejection fraction measured by different echocardiographic methods in congenital heart diseases involving the right ventricle

In CHD with RV volumetric or barometric overload, LV shape is altered. Little is known about the accuracy in this population of left ventricular (LV) volumes and ejection fraction (EF) measurement by standard echocardiographic methods using geometrical assumption: Teicholz, biplane Simpson and real-time 3D echocardiography (RT-3DE). Three-dimensional knowledge-based reconstruction (3D-KR) derived from two-dimensional echocardiographic imaging is a novel technique that has no geometrical assumption. The aim of our study is to assess the accuracy of several echocardiographic methods for measuring LV volumes and EF compared to cardiac magnetic resonance (CMR) measurements (gold standard) in this population. 68 patients (mean age 13,3±4 years) with Congenital Heart Diseases (CHD) involving the RV and referred for cardiac MRI, were included. Among them, 13 patients had barometric overload, 37 patients had volumetric overload, and 18 patients had mixed overload. Echocardiographic images acquisition was performed using a standard ultrasound scanner linked to a Ventripoint Medical Systems unit. Analyzed parameters were end-diastolic volume (EDV), end-systolic volume (ESV), and LVEF measured by Teicholz, Simpson’s modified formula and RT-3DE (GE Vingmed QVG Auto-4D). The method of disks was used for CMR LV volumes. Intra-observer, inter-observer, and inter-technique variability was assessed using intraclass correlation coefficient (CC), Pearson’s CC, coefficients of variation, and Bland-Altman analysis. Feasibility was 98% for Teicholz Method and 3D-KR, 71% for Simpson’s modified formula, and 73% for RT-3DE. We found globally poor correlation and agreement for volumes and EF between the different methods and MRI. The agreement was better when RV volumes were lower than 120 ml/m2 (and thus, LV shape was less altered). LV volumes and EFs cannot be measured accurately by echocardiography in patients with dilated right ventricles.

0241: Knowledge-based 3D reconstruction compared to MRI for evaluation of right ventricular volumes and function in congenital heart diseases affecting the right ventricle

Right ventricular (RV) volume and ejection fraction (RVEF) measurements are essential in the management of children with congenital heart disease. Cardiac Magnetic resonance imaging (MRI) is considered the reference method for RV volumes and RVEF measurements. Three-dimensional knowledge-based reconstruction (3D-KR) derived from two-dimensional echocardiographic imaging is a novel technique. The aim of this study was to assess the feasibility and reliability of this technique in children with diverse CHD involving the right ventricle. 103 children (range age 0,1 to 18 years) referred for cardiac MRI, were included. Among them, 33 patients had barometric overload, 40 patients had volumetric overload, 18 patients had mixed overload, and 12 had Fontan circulation. Echocardiographic image acquisition was performed using a standard ultrasound probe linked to a Ventripoint Medical Systems unit. Parameters analysed were end-diastolic volume (EDV), end-systolic volume (ESV), and RVEF. The method of disk was used for CMR RV volumes. Intra-observer, inter-observer, and inter-technique variability was assessed using coefficients of variation (COV), and Bland-Altman analysis. Feasibility of 3D-KR was 100%. Echocardiographic RV volumes correlated well with CMR (EDV, CC=0.96; ESV, ICC=0.93; RVEF, ICC=0.75). For inter-observer analyses, COV were 8% for EDV, 15% for ESV, and 17% for EF. For intra-observer analyses, COV were 4% for EDV, 7% for ESV, and 9% for EF. The correlation of volumes and RVEF with MRI was slightly worse in the group with mixed overload compared with patients with volumetric or barometric overload. 3D-RVEF was overestimated compared with MRI whereas the volumes tend to be underestimated. 3D-KR is feasible in children. It provides accurate and reproducible measurements of RV volumes. This new technique can be used as an accurate routine tool to assess RV function in CHD with pure barometric or volumetric overload. Abstract 0241 - Figure: RV-EDV Right Ventricular End Diastolic Volume

Feasibility and accuracy of left ventricular volumes and ejection fraction measured by different echocardiographic methods in congenital heart diseases involving the right ventricle

In CHD with RV volumetric or barometric overload, LV shape is altered. Little is known about the accuracy in this population of left ventricular (LV) volumes and ejection fraction (EF) measurement by standard echocardiographic methods using geometrical assumption: Teicholz, biplane Simpson and real-time 3D echocardiography (RT-3DE). Three-dimensional knowledge-based reconstruction (3D-KR) derived from two-dimensional echocardiographic imaging is a novel technique that has no geometrical assumption. The aim of our study is to assess the accuracy of several echocardiographic methods for measuring LV volumes and EF compared to cardiac magnetic resonance (CMR) measurements (gold standard) in this population. 68 patients (mean age 13,3 ± 4 years) with Congenital Heart Diseases (CHD) involving the RV and referred for cardiac MRI, were included. Among them, 13 patients had barometric overload, 37 patients had volumetric overload, and 18 patients had mixed overload. Echocardiographic images acquisition was performed using a standard ultrasound scanner linked to a Ventripoint Medical Systems unit. Analyzed parameters were end-diastolic volume (EDV), end-systolic volume (ESV), and LVEF measured by Teicholz, Simpson's modified formula and RT-3DE (GE Vingmed QVG Auto-4D). The method of disks was used for CMR LV volumes. Intra-observer, inter-observer, and inter-technique variability was assessed using intraclass correlation coefficient (CC), Pearson's CC, coefficients of variation, and Bland-Altman analysis. Feasibility was 98% for Teicholz Method and 3D-KR, 71% for Simpson's modified formula, and 73% for RT-3DE. We found globally poor correlation and agreement for volumes and EF between the different methods and MRI. The agreement was better when RV volumes were lower than 120 mL/m 2 (and thus, LV shape was less altered). LV volumes and EFs cannot be measured accurately by echocardiography in patients with dilated right ventricles.

Knowledge-based 3D reconstruction compared to MRI for evaluation of right ventricular volumes and function in congenital heart diseases affecting the right ventricle

Right ventricular (RV) volume and ejection fraction (RVEF) measurements are essential in the management of children with congenital heart disease. Cardiac magnetic resonance imaging (MRI) is considered the reference method for RV volumes and RVEF measurements. Three-dimensional knowledge-based reconstruction (3D-KR) derived from two-dimensional echocardiographic imaging is a novel technique. The aim of this study was to assess the feasibility and reliability of this technique in children with diverse CHD involving the right ventricle. 103 children (range age 0.1 to 18 years) referred for cardiac MRI, were included. Among them, 33 patients had barometric overload, 40 patients had volumetric overload, 18 patients had mixed overload, and 12 had Fontan circulation. Echocardiographic image acquisition was performed using a standard ultrasound probe linked to a Ventripoint Medical Systems unit. Parameters analysed were end-diastolic volume (EDV), end-systolic volume (ESV), and RVEF. The method of disk was used for CMR RV volumes. Intra-observer, inter-observer, and inter-technique variability was assessed using coefficients of variation (COV), and Bland-Altman analysis. ( Fig. 1 ) Feasibility of 3D-KR was 100%. Echocardiographic RV volumes correlated well with CMR (EDV, CC = 0.96; ESV, ICC = 0.93; RVEF, ICC = 0.75). For inter-observer analyses, COV were 8% for EDV, 15% for ESV, and 17% for EF. For intra-observer analyses, COV were 4% for EDV, 7% for ESV, and 9% for EF. The correlation of volumes and RVEF with MRI was slightly worse in the group with mixed overload compared with patients with volumetric or barometric overload. 3D-RVEF was overestimated compared with MRI whereas the volumes tend to be underestimated. 3D-KR is feasible in children. It provides accurate and reproducible measurements of RV volumes. This new technique can be used as an accurate routine tool to assess RV function in CHD with pure barometric or volumetric overload.

Evaluation of knowledge-based reconstruction for magnetic resonance volumetry of the right ventricle in tetralogy of Fallot.

Cardiac magnetic resonance using the Simpson method is the gold standard for right ventricular volumetry. However, this method is time-consuming and not without sources of error. Knowledge-based reconstruction is a novel post-processing approach that reconstructs the right ventricular endocardial shape based on anatomical landmarks and a database of various right ventricular configurations. To assess the feasibility, accuracy and labor intensity of knowledge-based reconstruction in repaired tetralogy of Fallot (TOF). The short-axis cine cardiac MR datasets of 35 children and young adults (mean age 14.4 ± 2.5years) after TOF repair were studied using both knowledge-based reconstruction and the Simpson method. Intraobserver, interobserver and inter-method variability were assessed using Bland-Altman analyses. Knowledge-based reconstruction was feasible and highly accurate as compared to the Simpson method. Intra- and inter-method variability for knowledge-based reconstruction measurements showed good agreement. Volumetric assessment using knowledge-based reconstruction was faster when compared with the Simpson method (10.9 ± 2.0 vs. 7.1 ± 2.4min, P < 0.001). In patients with repaired tetralogy of Fallot, knowledge-based reconstruction is a feasible, accurate and reproducible method for measuring right ventricular volumes and ejection fraction. The post-processing time of right ventricular volumetry using knowledge-based reconstruction was significantly shorter when compared with the routine Simpson method.

Right Ventricular Assessment in Adult Congenital Heart Disease Patients With a RV to PA Conduit: Validation of a 3D Knowledge Based Reconstruction Method

Assessment of right ventricular (RV) volumes and function is important in congenital heart disease (CHD) patients with RV to pulmonary artery (PA) conduits. Cardiac magnetic resonance imaging (CMR) is considered the reference standard. Three-dimensional knowledge-based reconstruction (3DKBR) derived from two-dimensional echocardiographic imaging with magnetic tracking of the transducer position is a novel approach to RV assessment that has been validated in other CHD populations. The aims of this study were: 1) to determine patterns of RV shape across the spectrum of CHD with RV to PA conduits using CMR; 2) to assess the feasibility and accuracy of 3DKBR of the RV in CHD patients with RV to PA conduits.

Right Ventricular Strain in Pulmonary Hypertension

Since 2009, there have been ≥170 articles published in the cardiopulmonary literature on right ventricular (RV) echocardiographic strain imaging, including several in Circulation: Cardiovascular Imaging . Of particular interest has been the effort to use RV echocardiographic strain imaging to assess RV systolic function in pulmonary hypertension and the relationship of RV strain to disease severity and outcomes. In this issue of Circulation: Cardiovascular Imaging , Fine et al,1 from the Mayo Clinic echo group, report on retrospectively evaluated data on the relationship of RV strain to outcomes in the largest such study to date, encompassing 575 patients with known or suspected pulmonary hypertension without elevated pulmonary venous pressure during a median follow-up period of 16.5 months.1 The data show a strong association between reductions in mean longitudinal strain and all-cause mortality, and cardiopulmonary mortality and cardiopulmonary events. An exhaustive biostatistical analysis shows the relationship to be quantitative, stronger than that of other echo indices including tricuspid annular plane systolic excursion, independent of clinical covariates and resulting in a significant improvement in predictive value when combined with relevant clinical variables, as reflected in a significant increase in the integrated discrimination improvement index and the c-statistic for the primary end point. Thus, the results promise to improve clinical risk assessment significantly for such patients and may improve clinical decision making. Article see p 711 The apparent benefit is, in large part, a reflection of the relatively weak performance of older 2-dimensional (2D) echocardiographic indices of RV performance including fractional area change and tricuspid annular plane systolic excursion in this setting. RV imaging has been a minefield for echocardiography in adults since its inception. The complexity of ventricular shape, the thinness of the RV free wall, and the limitations in adults of transthoracic and subcostal windows in permitting full visualization …

Evaluation of knowledge-based reconstruction for magnetic resonance volumetry of the right ventricle in tetralogy of fallot

Cardiac magnetic resonance using the Simpson method is the gold standard for right ventricular volumetry. However, this method is time-consuming and not without sources of error. Knowledge-based reconstruction is a novel post-processing approach that reconstructs the right ventricular endocardial shape based on anatomical landmarks and a database of various right ventricular configurations. To assess the feasibility, accuracy and labor intensity of knowledge-based reconstruction in repaired tetralogy of Fallot (TOF). The short-axis cine cardiac MR datasets of 35 children and young adults (mean age 14.4 ± 2.5 years) after TOF repair were studied using both knowledge-based reconstruction and the Simpson method. Intraobserver, interobserver and inter-method variability were assessed using Bland-Altman analyses. Knowledge-based reconstruction was feasible and highly accurate as compared to the Simpson method. Intra- and inter-method variability for knowledge-based reconstruction measurements showed good agreement. Volumetric assessment using knowledge-based reconstruction was faster when compared with the Simpson method (10.9 ± 2.0 vs. 7.1 ± 2.4 min, P < 0.001). In patients with repaired tetralogy of Fallot, knowledge-based reconstruction is a feasible, accurate and reproducible method for measuring right ventricular volumes and ejection fraction. The post-processing time of right ventricular volumetry using knowledge-based reconstruction was significantly shorter when compared with the routine Simpson method.

Three-dimensional modeling of the right ventricle from two-dimensional transthoracic echocardiographic images: utility of knowledge-based reconstruction in pulmonary arterial hypertension

Three-dimensional modeling of the right ventricle from two-dimensional transthoracic echocardiographic images: utility of knowledge-based reconstruction in pulmonary arterial hypertension