Background: 4D flow MRI enables assessment of cardiac function and intra-cardiac blood flow dynamics from a single acquisition. However, due to the poor contrast between the chambers and... Show moreBackground: 4D flow MRI enables assessment of cardiac function and intra-cardiac blood flow dynamics from a single acquisition. However, due to the poor contrast between the chambers and surrounding tissue, quantitative analysis relies on the segmentation derived from a registered cine MRI acquisition. This requires an additional acquisition and is prone to imperfect spatial and temporal inter-scan alignment. Therefore, in this work we developed and evaluated deep learning-based methods to segment the left ventricle (LV) from 4D flow MRI directly. Methods: We compared five deep learning-based approaches with different network structures, data pre-processing and feature fusion methods. For the data pre-processing, the 4D flow MRI data was reformatted into a stack of short-axis view slices. Two feature fusion approaches were proposed to integrate the features from magnitude and velocity images. The networks were trained and evaluated on an in-house dataset of 101 subjects with 67,567 2D images and 3030 3D volumes. The performance was evaluated using various metrics including Dice, average surface distance (ASD), end-diastolic volume (EDV), end-systolic volume (ESV), LV ejection fraction (LVEF), LV blood flow kinetic energy (KE) and LV flow components. The Monte Carlo dropout method was used to assess the confidence and to describe the uncertainty area in the segmentation results. Results: Among the five models, the model combining 2D U-Net with late fusion method operating on short-axis reformatted 4D flow volumes achieved the best results with Dice of 84.52% and ASD of 3.14 mm. The best averaged absolute and relative error between manual and automated segmentation for EDV, ESV, LVEF and KE was 19.93 ml (10.39%), 17.38 ml (22.22%), 7.37% (13.93%) and 0.07 mJ (5.61%), respectively. Flow component results derived from automated segmentation showed high correlation and small average error compared to results derived from manual segmentation. Conclusions: Deep learning-based methods can achieve accurate automated LV segmentation and subsequent quantification of volumetric and hemodynamic LV parameters from 4D flow MRI without requiring an additional cine MRI acquisition. Show less
Long-term survival for univentricular heart patients with a Fontan circulation is nowadays excellent, with the majority of patients expecting to reach adulthood. Nevertheless, a general attrition... Show moreLong-term survival for univentricular heart patients with a Fontan circulation is nowadays excellent, with the majority of patients expecting to reach adulthood. Nevertheless, a general attrition rate remains present and the majority of Fontan patients will be faced with significant morbidity. However, no Fontan patient is the same and there is a need for better understanding which patients will do worse, ideally by (early) identification of adverse factors that can be optimized. In this thesis, the role of flow efficiency in the TCPC was thoroughly investigated leading to multiple new insights. A novel three-dimensional blood flow MR sequence (3D flow MRI) was developed and shown to be superior to conventional 2D and 4D flow MRI sequences which could potentially lead to a more widespread use. Adverse flow patterns associated with reduced flow efficiency were shown at multiple areas within the TCPC which were related to adverse energetics. Increased 4D flow MRI derived energetics in turn are associated with reduced exercise capacity and increased levels of liver fibrosis/venous congestion. A focus on conduit size adequacy demonstrated that the currently used 16-20mm extracardiac conduits become undersized for teenage and adolescent Fontan patients. Undersized conduits proved to be an important factor leading to reduced flow efficiency, especially during exercise conditions. Achievement of optimal blood flow in Fontan patients may ultimately lead to improved long-term outcome. Show less
Background: Aortic flow parameters can be quantified using 4D flow MRI. However, data are sparse on how different methods of analysis influence these parameters and how these parameters evolve... Show moreBackground: Aortic flow parameters can be quantified using 4D flow MRI. However, data are sparse on how different methods of analysis influence these parameters and how these parameters evolve during systole.Purpose: To assess multiphase segmentations and multiphase quantification of flow-related parameters in aortic 4D flow MRI.Study Type: Prospective.Population: 40 healthy volunteers (50% male, 28.9 +/- 5.0 years) and 10 patients with thoracic aortic aneurysm (80% male, 54 +/- 8 years).Field Strength/Sequence: 4D flow MRI with a velocity encoded turbo field echo sequence at 3 T.Assessment: Phase-specific segmentations were obtained for the aortic root and the ascending aorta. The whole aorta was segmented in peak systole. In all aortic segments, time to peak (TTP; for flow velocity, vorticity, helicity, kinetic energy, and viscous energy loss) and peak and time-averaged values (for velocity and vorticity) were calculated.Statistical Tests: Static vs. phase-specific models were assessed using Bland-Altman plots. Other analyses were performed using phase-specific segmentations for aortic root and ascending aorta. TTP for all parameters was compared to TTP of flow rate using paired t-tests. Time-averaged and peak values were assessed using Pearson correlation coefficient. P < 0.05 was considered statistically significant.Results: In the combined group, velocity in static vs. phase-specific segmentations differed by 0.8 cm/sec for the aortic root, and 0.1 cm/sec (P = 0.214) for the ascending aorta. Vorticity differed by 167 sec(-1) mL(-1) (P = 0.468) for the aortic root, and by 59 sec(-1) mL(-1) (P = 0.481) for the ascending aorta. Vorticity, helicity, and energy loss in the ascending aorta, aortic arch, and descending aorta peaked significantly later than flow rate. Time-averaged velocity and vorticity values correlated significantly in all segments.Data Conclusion: Static 4D flow MRI segmentation yields comparable results as multiphase segmentation for flow-related parameters, eliminating the need for time-consuming multiple segmentations. However, multiphase quantification is necessary for assessing peak values of aortic flow-related parameters. Show less
Sun, X.W.; Cheng, L.H.; Plein, S.; Garg, P.; Moghari, M.H.; Geest, R.J. van der 2023
Purpose: We aimed to design and evaluate a deep learning-based method to automatically predict the time-varying in-plane blood flow velocity within the cardiac cavities in long-axis cine MRI,... Show morePurpose: We aimed to design and evaluate a deep learning-based method to automatically predict the time-varying in-plane blood flow velocity within the cardiac cavities in long-axis cine MRI, validated against 4D flow. Methods: A convolutional neural network (CNN) was implemented, taking cine MRI as the input and the in-plane velocity derived from the 4D flow acquisition as the ground truth. The method was evaluated using velocity vector end-point error (EPE) and angle error. Additionally, the E/A ratio and diastolic function classification derived from the predicted velocities were compared to those derived from 4D flow. Results: For intra-cardiac pixels with a velocity > 5 cm/s, our method achieved an EPE of 8.65 cm/s and angle error of 41.27 degrees. For pixels with a velocity > 25 cm/s, the angle error significantly degraded to 19.26 degrees. Although the averaged blood flow velocity prediction was under-estimated by 26.69%, the high correlation (PCC = 0.95) of global time-varying velocity and the visual evaluation demonstrate a good agreement between our prediction and 4D flow data. The E/A ratio was derived with minimal bias, but with considerable mean absolute error of 0.39 and wide limits of agreement. The diastolic function classification showed a high accuracy of 86.9%. Conclusion: Using a deep learning-based algorithm, intra-cardiac blood flow velocities can be predicted from long-axis cine MRI with high correlation with 4D flow derived velocities. Visualization of the derived velocities provides adjunct functional information and may potentially be used to derive the E/A ratio from conventional CMR exams. Show less
Juffermans, J.F.; Assen, H.C. van; Kiefte, B.J.C. te; Ramaekers, M.J.F.G.; Palen, R.L.F. van der; Boogaard, P. van den; ... ; Westenberg, J.J.M. 2022
(1) Background: Aorta hemodynamics have been associated with aortic remodeling, but the reproducibility of its assessment has been evaluated marginally in patients with thoracic aortic aneurysm ... Show more(1) Background: Aorta hemodynamics have been associated with aortic remodeling, but the reproducibility of its assessment has been evaluated marginally in patients with thoracic aortic aneurysm (TAA). The current study evaluated intra- and interobserver reproducibility of 4D flow MRI-derived hemodynamic parameters (normalized flow displacement, flow jet angle, wall shear stress (WSS) magnitude, axial WSS, circumferential WSS, WSS angle, vorticity, helicity, and local normalized helicity (LNH)) in TAA patients; (2) Methods: The thoracic aorta of 20 patients was semi-automatically segmented on 4D flow MRI data in 5 systolic phases by 3 different observers. Each time-dependent segmentation was manually improved and partitioned into six anatomical segments. The hemodynamic parameters were quantified per phase and segment. The coefficient of variation (COV) and intraclass correlation coefficient (ICC) were calculated; (3) Results: A total of 2400 lumen segments were analyzed. The mean aneurysm diameter was 50.8 +/- 2.7 mm. The intra- and interobserver analysis demonstrated a good reproducibility (COV = 16-30% and ICC = 0.84-0.94) for normalized flow displacement and jet angle, a very good-to-excellent reproducibility (COV = 3-26% and ICC = 0.87-1.00) for all WSS components, helicity and LNH, and an excellent reproducibility (COV = 3-10% and ICC = 0.96-1.00) for vorticity; (4) Conclusion: 4D flow MRI-derived hemodynamic parameters are reproducible within the thoracic aorta in TAA patients. Show less
Aim This study explores the relationship between in vivo 4D flow cardiovascular magnetic resonance (CMR) derived blood flow energetics in the total cavopulmonary connection (TCPC), exercise... Show moreAim This study explores the relationship between in vivo 4D flow cardiovascular magnetic resonance (CMR) derived blood flow energetics in the total cavopulmonary connection (TCPC), exercise capacity and CMR-derived liver fibrosis/congestion. Background The Fontan circulation, in which both caval veins are directly connected with the pulmonary arteries (i.e. the TCPC) is the palliative approach for single ventricle patients. Blood flow efficiency in the TCPC has been associated with exercise capacity and liver fibrosis using computational fluid dynamic modelling. 4D flow CMR allows for assessment of in vivo blood flow energetics, including kinetic energy (KE) and viscous energy loss rate (EL). Methods Fontan patients were prospectively evaluated between 2018 and 2021 using a comprehensive cardiovascular and liver CMR protocol, including 4D flow imaging of the TCPC. Peak oxygen consumption (VO2) was determined using cardiopulmonary exercise testing (CPET). Iron-corrected whole liver T1 (cT1) mapping was performed as a marker of liver fibrosis/congestion. KE and EL in the TCPC were computed from 4D flow CMR and normalized for inflow. Furthermore, blood flow energetics were compared between standardized segments of the TCPC. Results Sixty-two Fontan patients were included (53% male, 17.3 +/- 5.1 years). Maximal effort CPET was obtained in 50 patients (peak VO2 27.1 +/- 6.2 ml/kg/min, 56 +/- 12% of predicted). Both KE and EL in the entire TCPC (n = 28) were significantly correlated with cT1 (r = 0.50, p = 0.006 and r = 0.39, p = 0.04, respectively), peak VO2 (r = - 0.61, p = 0.003 and r = - 0.54, p = 0.009, respectively) and % predicted peak VO2 (r = - 0.44, p = 0.04 and r = - 0.46, p = 0.03, respectively). Segmental analysis indicated that the most adverse flow energetics were found in the Fontan tunnel and left pulmonary artery. Conclusions Adverse 4D flow CMR derived KE and EL in the TCPC correlate with decreased exercise capacity and increased levels of liver fibrosis/congestion. 4D flow CMR is promising as a non-invasive screening tool for identification of patients with adverse TCPC flow efficiency. Show less
Purpose To assess errors associated with EPI-accelerated intracardiac 4D flow MRI (4DEPI) with EPI factor 5, compared with non-EPI gradient echo (4DGRE). Methods Three 3T MRI experiments were... Show morePurpose To assess errors associated with EPI-accelerated intracardiac 4D flow MRI (4DEPI) with EPI factor 5, compared with non-EPI gradient echo (4DGRE). Methods Three 3T MRI experiments were performed comparing 4DEPI to 4DGRE: steady flow through straight tubes, pulsatile flow in a left-ventricle phantom, and intracardiac flow in 10 healthy volunteers. For each experiment, 4DEPI was repeated with readout and blip phase-encoding gradient in different orientations, parallel or perpendicular to the flow direction. In vitro flow rates were compared with timed volumetric collection. In the left-ventricle phantom and in vivo, voxel-based speed and spatio-temporal median speed were compared between sequences, as well as mitral and aortic transvalvular net forward volume. Results In steady-flow phantoms, the flow rate error was largest (12%) for high velocity (>2 m/s) with 4DEPI readout gradient parallel to the flow. Voxel-based speed and median speed in the left-ventricle phantom were <= 5.5% different between sequences. In vivo, mean net forward volume inconsistency was largest (6.4 +/- 8.5%) for 4DEPI with nonblip phase-encoding gradient parallel to the main flow. The difference in median speed for 4DEPI versus 4DGRE was largest (9%) when the 4DEPI readout gradient was parallel to the flow. Conclusions Velocity and flow rate are inaccurate for 4DEPI with EPI factor 5 when flow is parallel to the readout or blip phase-encoding gradient. However, mean differences in flow rate, voxel-based speed, and spatio-temporal median speed were acceptable (<= 10%) when comparing 4DEPI to 4DGRE for intracardiac flow in healthy volunteers. Show less
Objectives Degenerative thoracic aortic aneurysm (TAA) patients are known to be at risk of life-threatening acute aortic events. Guidelines recommend preemptive surgery at diameters of greater than... Show moreObjectives Degenerative thoracic aortic aneurysm (TAA) patients are known to be at risk of life-threatening acute aortic events. Guidelines recommend preemptive surgery at diameters of greater than 55 mm, although many patients with small aneurysms show only mild growth rates and more than half of complications occur in aneurysms below this threshold. Thus, assessment of hemodynamics using 4-dimensional flow magnetic resonance has been of interest to obtain more insights in aneurysm development. Nonetheless, the role of aberrant flow patterns in TAA patients is not yet fully understood. Materials and Methods A total of 25 TAA patients and 22 controls underwent time-resolved 3-dimensional phase contrast magnetic resonance imaging with 3-directional velocity encoding (ie, 4-dimensional flow magnetic resonance imaging). Hemodynamic parameters such as vorticity, helicity, and wall shear stress (WSS) were calculated from velocity data in 3 anatomical segments of the ascending aorta (root, proximal, and distal). Regional WSS distribution was assessed for the full cardiac cycle. Results Flow vorticity and helicity were significantly lower for TAA patients in all segments. The proximal ascending aorta showed a significant increase in peak WSS in the outer curvature in TAA patients, whereas WSS values at the inner curvature were significantly lower as compared with controls. Furthermore, positive WSS gradients from sinotubular junction to midascending aorta were most prominent in the outer curvature, whereas from midascending aorta to brachiocephalic trunk, the outer curvature showed negative WSS gradients in the TAA group. Controls solely showed a positive gradient at the inner curvature for both segments. Conclusions Degenerative TAA patients show a decrease in flow vorticity and helicity, which is likely to cause perturbations in physiological flow patterns. The subsequent differing distribution of WSS might be a contributor to vessel wall remodeling and aneurysm formation. Show less
The thesis summarizes the results on the prevalence and evolution of neo-aortic root pathology and surgical cardiovascular outcomes in patients after arterial switch operation (ASO) for... Show moreThe thesis summarizes the results on the prevalence and evolution of neo-aortic root pathology and surgical cardiovascular outcomes in patients after arterial switch operation (ASO) for transposition of the great arteries. Furthermore, thoracic aortic blood flow hemodynamics were investigated in relation to post-ASO geometry and root pathology with advanced non-invasive four-dimensional flow cardiovascular magnetic resonance imaging techniques. Show less
Juffermans, J.F.; Westenberg, J.J.M.; Boogaard, P.J. van den; Roest, A.A.W.; Assen, H.C. van; Palen, R.L.F. van der; Lamb, H.J. 2020
Background Hemodynamic aorta parameters can be derived from 4D flow MRI, but this requires lumen segmentation. In both commercially available and research 4D flow MRI software tools, lumen... Show moreBackground Hemodynamic aorta parameters can be derived from 4D flow MRI, but this requires lumen segmentation. In both commercially available and research 4D flow MRI software tools, lumen segmentation is mostly (semi-)automatically performed and subsequently manually improved by an observer. Since the segmentation variability, together with 4D flow MRI data and image processing algorithms, will contribute to the reproducibility of patient-specific flow properties, the observer's lumen segmentation reproducibility and repeatability needs to be assessed.Purpose To determine the interexamination, interobserver reproducibility, and intraobserver repeatability of aortic lumen segmentation on 4D flow MRI.Study Type Prospective and retrospective.Population A healthy volunteer cohort of 10 subjects who underwent 4D flow MRI twice. Also, a clinical cohort of six subjects who underwent 4D flow MRI once.Field Strength/Sequence 3T; time-resolved three-directional and 3D velocity-encoded sequence (4D flow MRI).Assessment The thoracic aorta was segmented on the 4D flow MRI in five systolic phases. By positioning six planes perpendicular to a segmentation's centerline, the aorta was divided into five segments. The volume, surface area, centerline length, maximal diameter, and curvature radius were determined for each segment.Statistical Tests To assess the reproducibility, the coefficient of variation (COV), Pearson correlation coefficient (r), and intraclass correlation coefficient (ICC) were calculated.Results The interexamination and interobserver reproducibility and intraobserver repeatability were comparable for each parameter. For both cohorts there was very good reproducibility and repeatability for volume, surface area, and centerline length (COV = 10-32%, r = 0.54-0.95 and ICC = 0.65-0.99), excellent reproducibility and repeatability for maximal diameter (COV = 3-11%, r = 0.94-0.99, ICC = 0.94-0.99), and good reproducibility and repeatability for curvature radius (COV = 25-62%, r = 0.73-0.95, ICC = 0.84-0.97).Data Conclusion This study demonstrated no major reproducibility and repeatability limitations for 4D flow MRI aortic lumen segmentation.Level of Evidence 3Technical Efficacy Stage 2 Show less
Background:There is an emerging body of evidence that supports the potential clinical value of left ventricular (LV) intracavity blood flow kinetic energy (KE) assessment using four-dimensional... Show moreBackground:There is an emerging body of evidence that supports the potential clinical value of left ventricular (LV) intracavity blood flow kinetic energy (KE) assessment using four-dimensional flow cardiovascular magnetic resonance imaging (4D flow CMR). The aim of this systematic review is to summarize studies evaluating LV intracavity blood flow KE quantification methods and its potential clinical significance.Methods:A systematic review search was carried out on Medline, Pubmed, EMBASE and CINAHL.Results:Of the 677 articles screened, 16 studies met eligibility. These included six (37%) studies on LV diastolic function, another six (37%) studies on heart failure or cardiomyopathies, three (19%) studies on ischemic heart disease or myocardial infarction and finally, one (6%) study on valvular heart disease, namely, mitral regurgitation. One of the main strengths identified by these studies is high reproducibility of LV blood flow KE hemodynamic assessment (mean coefficient of variability = 6 +/- 2%) for the evaluation of LV diastolic function.Conclusions:The evidence gathered in this systematic review suggests that LV blood flow KE has great promise for LV hemodynamic assessment. Studies showed increased diagnostic confidence at no cost of additional time. Results were highly reproducible with low intraobserver variability. Show less
Background Patients with transposition of the great arteries (TGA) have an altered aortic geometry after an arterial switch operation (ASO), with neo-aortic root dilatation as an important... Show moreBackground Patients with transposition of the great arteries (TGA) have an altered aortic geometry after an arterial switch operation (ASO), with neo-aortic root dilatation as an important complication. Geometry-related aortic hemodynamics have been assumed to contribute to pathology of the ascending aorta (AAo).Purpose To evaluate aortic flow displacement (FD) and regional wall shear stress (WSS) in relation to ascending neo-aortic geometry in children after ASO.Study Type Prospective.Population Twenty-eight TGA patients after ASO and 10 healthy volunteers.Field Strength/Sequence 3.0T/4D flow (segmented fast-spoiled echo pulse), noncontrast-enhanced MR angiography (Dixon), and anatomic images (SSFP).Assessment Aortic diameters and body surface area-indexed aortic dimensions (Z-scores), normalized FD and planar ascending aortic WSS.Statistical Tests Mann-Whitney and chi-square tests for differences in FD magnitude, WSS, and FD directionality between groups, respectively. Spearman rank correlation to assess the degree of association between aortic geometry, FD and WSS parameters. Shapiro-Wilk test to evaluate distribution normality on the absolute differences in octant location between FD and WSS.Results TGA patients showed a significantly dilated proximal AAo and relatively small mid-AAo dimensions at the level of the pulmonary arteries (Z-scores neo-aortic root: 4.38 +/- 1.96 vs. 1.52 +/- 0.70, P < 0.001; sinotubular junction: 3.48 +/- 2.67 vs. 1.38 +/- 1.30, P = 0.010; mid-AAo: 0.32 +/- 3.06 vs. 1.69 +/- 1.24, P = 0.001). FD magnitude was higher in TGA patients (neo-aortic root: 0.048 +/- 0.027 vs. 0.021 +/- 0.006, P < 0.001; sinotubular junction: 0.054 +/- 0.037 vs. 0.029 +/- 0.013, P < 0.05) and was related to the neo-aortic Z-score. Clear areas of higher WSS at the right and anterior aortic wall regions along the distal AAo were detected in TGA patients, most pronounced in those with relatively smaller mid-AAo diameters.Data Conclusion TGA-specific geometry related to the ASO, evidenced by neo-aortic root dilatation and a sudden change in vessel diameter at mid-AAo level, leads to more aortic flow asymmetry in the proximal AAo and WSS distribution with higher WSS at the right and anterior aortic wall regions along the distal AAo.Technical Efficacy Stage: 3J. Magn. Reson. Imaging 2020;51:1105-1116. Show less
Background The prevalence of valvular aortic stenosis (AS) increases as the population ages. Echocardiographic measurements of peak jet velocity (V-peak), mean pressure gradient (P-mean), and... Show moreBackground The prevalence of valvular aortic stenosis (AS) increases as the population ages. Echocardiographic measurements of peak jet velocity (V-peak), mean pressure gradient (P-mean), and aortic valve area (AVA) determine AS severity and play a pivotal role in the stratification towards valvular replacement. A multimodality imaging approach might be needed in cases of uncertainty about the actual severity of the stenosis. Purpose To compare four-dimensional phase-contrast magnetic resonance (4D PC-MR), two-dimensional (2D) PC-MR, and transthoracic echocardiography (TTE) for quantification of AS. Study Type Prospective. Population Twenty patients with various degrees of AS (69.3 +/- 5.0 years). Field Strength/Sequences 4D PC-MR and 2D PC-MR at 3T. Assessment We compared V-peak, P-mean, and AVA between TTE, 4D PC-MR, and 2D PC-MR. Flow eccentricity was quantified by means of normalized flow displacement, and its influence on the accuracy of TTE measurements was investigated. Statistical Tests Pearson's correlation, Bland-Altman analysis, paired t-test, and intraclass correlation coefficient. Results 4D PC-MR measured higher V-peak (r = 0.95, mean difference + 16.4 +/- 10.7%, P <0.001), and P-mean (r = 0.92, mean difference + 14.9 +/- 16.0%, P = 0.013), but a less critical AVA (r = 0.80, mean difference + 19.9 +/- 20.6%, P = 0.002) than TTE. In contrast, unidirectional 2D PC-MR substantially underestimated AS severity when compared with TTE. Differences in V-peak between 4D PC-MR and TTE showed to be strongly correlated with the eccentricity of the flow jet (r = 0.89, P <0.001). Use of 4D PC-MR improved the concordance between V-peak and AVA (from 0.68 to 0.87), and between PG(mean) and AVA (from 0.68 to 0.86). Data Conclusion 4D PC-MR improves the concordance between the different AS parameters and could serve as an additional imaging technique next to TTE. Future studies should address the potential value of 4D PC-MR in patients with discordant echocardiographic parameters. Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019. Show less
Kamphuis, V.P.; Elbaz, M.S.M.; Boogaard, P.J. van den; Kroft, L.J.M.; Geest, R.J. van der; Roos, A. de; ... ; Roest, A.A.W. 2019
Aims To non-invasively assess intraventricular viscous energy loss (EL) and proportionality to kinetic energy (KE) in Fontan patients using 4D flow magnetic resonance imaging (MRI) and compare to... Show moreAims To non-invasively assess intraventricular viscous energy loss (EL) and proportionality to kinetic energy (KE) in Fontan patients using 4D flow magnetic resonance imaging (MRI) and compare to healthy controls.Methods and results Thirty Fontan patients and 15 controls underwent 4D flow MRI. Ventricular EL was computed and normalized by end-diastolic volume (EDV). EL over the cardiac cycle (ELcycle) relative to the average kinetic energy (KEcycle) was quantified using a dimensionless index, ELindex (ELcycle/KEcycle). EL was significantly elevated in Fontan patients compared to controls (ELcycle/EDV: 3.7 vs. 2.6J/m(3), P=0.001). Fontan patients with inflow of blood entering a ventricle, which leaves that ventricle through a ventricular septal defect to the aorta, defined as discordant inflow-to-outflow showed significantly higher EL compared to patients with inflow of blood into the same ventricle from which the blood is ejected into the aorta, defined as concordant inflow-to-outflow (ELcycle/EDV: 6.8 vs. 3.2J/m(3), P=0.001). EL was not significantly different in Fontan patients with a systemic left vs. a systemic right ventricle (ELcycle/EDV: 3.5 vs. 3.6J/m(3), P=0.91). ELindex was significantly elevated in Fontan patients compared to controls (ELindex: 0.4 vs. 0.2, P<0.001). Highest ELindex was found in Fontan patients with discordant inflow-to-outflow compared to concordant inflow-to-outflow (0.5 vs. 0.3, P=0.01).Conclusion Fontan patients show disproportionate intraventricular EL relative to KE. Intraventricular EL is elevated in these patients compared to healthy controls, and highest EL is found in patients with discordant inflow-to-outflow. Show less
This thesis provides insight in the impact of congenital and acquired heart diseases on electrophysiology and hemodynamics in the heart, that could help understand the often complex... Show moreThis thesis provides insight in the impact of congenital and acquired heart diseases on electrophysiology and hemodynamics in the heart, that could help understand the often complex pathophysiological mechanisms involved in cardiovascular diseases and might aid in the early detection of patients prone to cardiovascular deterioration. The first part of this thesis shows the value of the electrocardiogram and vectorcardiogram in the assessment of patients with right-sided acquired and congenital heart defects. The 3D vectorcardiographic VG and SA could be valuable in the assessment of patients with right ventricular volume or pressure overload. The second part of this thesis shows significant steps towards clinical utility of 4D flow MRI. Valvular flow quantification with 4D flow MRI, especially in combination with automated valve tracking, has great potential as a future clinical standard. The third part of this thesis provides important insights in intraventricular hemodynamics in Fontan patients. In time to come, knowledge on intraventricular hemodynamics could aid in determining follow-up frequency and the ideal timing of initiation of heart failure management, perhaps even on an individual patient’s level. Moreover, these findings can create a platform for further research in the field of intraventricular hemodynamics in healthy subjects and different patient groups. Show less
Palen, R.L.F. van der; Roest, A.A.W.; Boogaard, P.J. van den; Roos, A. de; Blom, N.A.; Westenberg, J.J.M. 2018
