scholarly journals Comprehensive Assessment of Left Intraventricular Hemodynamics Using a Finite Element Method: An Application to Dilated Cardiomyopathy Patients

2021 ◽  
Vol 11 (23) ◽  
pp. 11165
Author(s):  
Pamela Franco ◽  
Julio Sotelo ◽  
Cristian Montalba ◽  
Bram Ruijsink ◽  
Eric Kerfoot ◽  
...  

In this paper, we applied a method for quantifying several left intraventricular hemodynamic parameters from 4D Flow data and its application in a proof-of-concept study in dilated cardiomyopathy (DCM) patients. In total, 12 healthy volunteers and 13 DCM patients under treatment underwent short-axis cine b-SSFP and 4D Flow MRI. Following 3D segmentation of the left ventricular (LV) cavity and registration of both sequences, several hemodynamic parameters were calculated at peak systole, e-wave, and end-diastole using a finite element approach. Sensitivity, inter- and intra-observer reproducibility of hemodynamic parameters were evaluated by analyzing LV segmentation. A local analysis was performed by dividing the LV cavity into 16 regions. We found significant differences between volunteers and patients in velocity, vorticity, viscous dissipation, energy loss, and kinetic energy at peak systole and e-wave. Furthermore, although five patients showed a recovered ejection fraction after treatment, their hemodynamic parameters remained low. We obtained several hemodynamic parameters with high inter- and intra-observer reproducibility. The sensitivity study revealed that hemodynamic parameters showed a higher accuracy when the segmentation underestimates the LV volumes. Our approach was able to identify abnormal flow patterns in DCM patients compared to volunteers and can be applied to any other cardiovascular diseases.

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Jeesoo Lee ◽  
Nadia El hangouche ◽  
Liliana Ma ◽  
Michael Scott ◽  
Michael Markl ◽  
...  

Introduction: 4D flow MRI can assess transvalvular velocity, but validation against continuous wave (CW) Doppler echo is limited in high-velocity regurgitation and stenosis situations. We sought to compare 4D flow MRI and echo peak velocity using a pulsatile echo-MRI flow phantom. Materials and Methods: An MRI-compatible flow phantom with restrictive orifice situated was driven by a left ventricular assist device at 50 bpm (figure 1A). Three orifice shapes were tested: circular, elliptical and 3D-printed patient-specific mitral regurgitant orifice model of prolapse with areas of 0.5, 0.41 and 0.35 cm 2 , respectively. CW Doppler was acquired with peak velocity extracted from the profile. Retrospectively-gated 4D flow MRI was performed (spatial resolution = 2 mm isotropic, temporal resolution = 36 ms, encoding velocity = 400 cm/s). Maximal velocity magnitude was extracted volumetrically (figure 1B). An echo-mimicking profile was also obtained with a “virtual” ultrasound beam in the 4D flow data to simulate CW Doppler (figure 1C). Bland-Altman analysis was used to assess the agreement of temporal peak velocities. Results: 4D flow MRI demonstrated a centrally directed jet for the circular and elliptical orifices and an oblique jet for the prolapse orifice (figure 1B). Peak velocities were in excellent agreement between 4D flow MRI vs. echo for the circular (peak: 5.13 vs. 5.08 m/s, bias = 0.06 ± 0.66 m/s, figure 1D) and the elliptical orifice (peak: 4.95 vs. 4.79 m/s, bias = 0.07 ± 0.87 m/s, figure 1E). The prolapse orifice velocity was underestimated somewhat by MRI by ~10% (peak: 4.41 vs. 4.90 m/s, bias=0.26±1.18, figure 1F). Conclusion: 4D flow MRI can quantify high velocities like echo for simple geometries while underestimating for more complex geometry, likely due to partial volume effects. Further investigation is warranted to systematically investigate the effects of 4D flow MRI spatial and temporal resolution as well as the jet angle on velocity quantification accuracy.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Philip A. Corrado ◽  
Jacob A. Macdonald ◽  
Christopher J. François ◽  
Niti R. Aggarwal ◽  
Jonathan W. Weinsaft ◽  
...  

Abstract Background Acute myocardial infarction (AMI) alters left ventricular (LV) hemodynamics, resulting in decreased global LV ejection fraction and global LV kinetic energy. We hypothesize that anterior AMI effects localized alterations in LV flow and developed a regional approach to analyze these local changes with 4D flow MRI. Methods 4D flow cardiac magnetic resonance (CMR) data was compared between 12 anterior AMI patients (11 males; 66 ± 12yo; prospectively acquired in 2016–2017) and 19 healthy volunteers (10 males; 40 ± 16yo; retrospective from 2010 to 2011 study). The LV cavity was contoured on short axis cine steady-state free procession CMR and partitioned into three regions: base, mid-ventricle, and apex. 4D flow data was registered to the short axis segmentation. Peak systolic and diastolic through-plane flows were compared region-by-region between groups using linear models of flow with age, sex, and heart rate as covariates. Results Peak systolic flow was reduced in anterior AMI subjects compared to controls in the LV mid-ventricle (fitted reduction = 3.9 L/min; P = 0.01) and apex (fitted reduction = 1.4 L/min; P = 0.02). Peak diastolic flow was also lower in anterior AMI subjects compared to controls in the apex (fitted reduction = 2.4 L/min; P = 0.01). Conclusions A regional method to analyze 4D LV flow data was applied in anterior AMI patients and controls. Anterior AMI patients had reduced regional flow relative to controls.


2018 ◽  
Vol 34 (6) ◽  
pp. 905-920 ◽  
Author(s):  
Vivian P. Kamphuis ◽  
Jos J. M. Westenberg ◽  
Roel L. F. van der Palen ◽  
Pieter J. van den Boogaard ◽  
Rob J. van der Geest ◽  
...  

2021 ◽  
Vol 22 (Supplement_2) ◽  
Author(s):  
MM Bissell ◽  
L Mills ◽  
DGW Cave ◽  
R Foley ◽  
JP Greenwood ◽  
...  

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): NIHR Background Pulmonary artery stenosis (PAS) occurs commonly in patients with tetralogy of fallot (ToF). Cardiac function and especially left ventricular longitudinal strain has been identified as an important prognostic factor for long term survival in ToF. The clinical relevance of unilateral PAS to long-term bi-ventricular function is poorly understood. Purpose We sought to evaluate the effect of resolving unilateral pulmonary artery obstruction on right and left ventricular performance. Methods We prospectively included 40 patients with TOF between 2016 and 2020, 20 who underwent unilateral PAS stenting and as comparison 20 who underwent surgical pulmonary valve replacement (PVR). MRI data was acquired during routine clinical care before and around 6-12 months after the procedure. 4 PAS patients attended additional research scans acquiring ventricular 4D flow MRI data. 4D flow MRI data was compared to the average kinetic energy curve of 10 age-matched healthy volunteers. Results Of the 20 patients undergoing PAS, 2 also underwent percutaneous PVR and were excluded from the comparison analysis. All patients in the PAs group showed an improvement in branch PA flow differential post procedure. Patients undergoing PAS were younger than those undergoing PVR (median 12 vs 19 years, p < 0.001). Other baseline anatomical and functional parameters including right ventricular (RV) volume indexed to body surface are (RVEDV/BSA) were comparable (pre PAS median 151 [122,170] vs pre PVR 162 [140,191]; p = 0.217). While in the PVR group the right ventricular volumes reduced in both end-diastole and end-systole, in the PAS group RV function improved due to reduced end-systolic volume with largely stable end-diastolic volumes. Changes in the left ventricle (LV) were even more interesting. In the PVR group ejection fraction improved due to an increase in end-diastolic volume with no improvement in ventricular longitudinal strain. In contrast, in the PAS group LV ejection fraction improved by a reduction in end-systolic volume and the PAS group showed a small but significant improvement in LV longitudinal strain. In addition, ¾ patients undergoing 4D flow MRI assessment showed LV kinetic energy curve more similar to the healthy volunteer averaged  LV kinetic energy curve after PAS. The 4th patient already had a near normal LV kinetic energy curve prior to PAS. Conclusion Unilateral PAS does not alter RV end-diastolic volumes but improves RV function. LV ejection fraction improvement is similar to that seen after PVR, but importantly PAS also improved LV longitudinal strain. This suggests that PAS might positively influence long term morbidity and mortality risk in ToF patients, but a larger multi-centre long term follow-up study is needed to confirm this.


2019 ◽  
pp. 42-49
Author(s):  
E. Yu. Glazkova ◽  
O. Yu. Dariy ◽  
S. A. Aleksandrova ◽  
V. N. Makarenko ◽  
M. I. Berseneva ◽  
...  

Objective. To assess phase-contrast MRI in the evaluation of left ventricular hemodynamics changes in various forms of hypertrophic cardiomyopathy.Materials and methods. 11 patients were examined: without pathology of the cardiovascular system (n = 3), with apical (n = 3), diffuse-septal (n = 2) and focal-basal (n = 3) types of hypertrophic cardiomyopathy. All patients underwent MRI of the heart with an additional phase-contrast sequence of the left ventricular area. Postprocessing carried out in the 4D FLOW application (Siemens).Results. Data were obtained on the geometry and dynamics of vortex diastolic flows in the left ventricular of all patients. In patients with hypertrophic cardiomyopathy, an increase in the distance to the center of the vortex and a decrease in the normalized area and peak velocity of the vortex is determined. The diffuse-septal type is characterized by a minimal vortex peak velocity; apical type - by the maximum vortex sphericity index. For patients with a focalbasal type of hypertrophic cardiomyopathy the maximum changes in blood flow are determined in late diastole (absence of vortexes).Conclusion. 4D FLOW Phase-contrast MRI allows identifying and assessing LV vortical flow. Quantitative analysis can be used to characterize the remodeling of LV blood flow of various types of hypertrophic cardiomyopathy.


Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Victoria Stoll ◽  
Aaron Hess ◽  
Eylem Levelt ◽  
Jonatan Eriksson ◽  
Petter Dyverfeldt ◽  
...  

Introduction: Heart failure (HF) due to dilated cardiomyopathy (DCM) is a complex syndrome in which numerous cellular, mechanical and flow processes/interactions become deranged. Insights into derangement of left ventricular intra-cardiac flow patterns and kinetic energy (KE) are now afforded by the use of 4D flow CMR. Previous studies have found derangements of intra-ventricular flow components and KE within DCM patients compared to healthy volunteers. Hypothesis: We hypothesised that increasing derangement in 4D flow measures would relate to: 1) decreased mechanical cardiac function, as assessed by myocardial strain, 2) increased levels of biochemical remodelling markers and 3) worsening patient symptoms and functional capacity. Methods: 26 idiopathic DCM patients (69% male, mean age 55±2 yr, LVEF 35±2%) and 10 controls (70% male, mean age 57±4yr, LVEF 68±1.2%) were assessed with 3T CMR. Results: The LV volume was divided into 4 functional components; direct flow (DF), delayed ejection flow (DEF), retained inflow (RI) and residual volume (RV). Compared to controls DCM’s had significantly decreased DF (11±1% vs 38±2%) and increased RV (51±2% vs 31±1%) (fig a). The KE at end diastole differed significantly for all flow components between groups (fig b). Circumferential strain was significantly impaired in DCM’s vs controls (-9.9±0.8% vs -19.7±0.5%, p<0.0001). DF KE correlated positively to the 6 minute walk test (6MWT) and strain, and negatively to the Minnesota HF questionnaire and BNP (fig c). Conclusions: DCM patients demonstrated less efficient blood flow patterns and deranged KE profiles. The greater the derangement of flow parameters from normal, the worse the myocardial strain, BNP, 6MWT and patient symptoms. This study suggests that flow parameter derangements are novel biomarkers of disease severity in DCM, correlating with established markers of prognosis such as BNP and 6MWT and may become useful in monitoring novel therapies and predicting prognosis.


Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Yue Ma ◽  
Alireza Vali ◽  
Maria Aristova ◽  
Ramez Abdalla ◽  
Sameer Ansari ◽  
...  

Introduction: Hemodynamic alterations of intracranial atherosclerotic disease (ICAD) patients may be associated with increased risk of stroke. Dual- venc 4D Flow MRI can provide time-resolved 3D hemodynamics with large velocity dynamic range, but clinical utility is limited by labor intensive analysis. We developed an automated tool to simplify analysis, rapidly extract and visualize hemodynamic parameters, bringing 4D Flow MRI closer to clinical practice. Purpose: To demonstrate clinical feasibility of a new automated tool for extracting hemodynamic parameters based on 4D Flow MRI, and evaluate intracranial hemodynamics in individual ICAD patients relative to normative reference values. Methods: Intracranial dual- venc 4D Flow MRI was acquired in 59 healthy subjects (32M, 48±15Y) and 16 ICAD patients (12M, 62±14Y). An in-house Matlab tool was used to quantify velocity and flow in each Circle of Willis vessel. Hemodynamic measures from the controls were used to derive normative parameter estimates using polynomial fit as a function of age. A hemodynamic profile for each patient included computing percent difference of peak velocity (PV) and flow rate (FR) in each vessel compared to reference values (Fig.1a-c), and showing results in a diagram (Fig.1d). Results: Fig.1e shows results for ICAD patients. 93.8% of stenotic vessels showed normal FR suggesting intracranial hemodynamic compensation. 62.5% of stenotic vessels showed abnormal PV and 75% of patients showed increased PV in at least one vessel in affected hemisphere. Among 3 patients with compensatory collateral circulation, 2 patients had more than 3 vessels with increased PV. This suggests PV is a more sensitive marker of stenosis than FR. Conclusions: We demonstrate the feasibility of an automated tool used with 4D Flow MRI to interrogate intracranial hemodynamics in ICAD patients. It has considerable promise for identifying new noninvasive biomarkers for individualized stroke risk stratification.


2017 ◽  
Vol 48 (1) ◽  
pp. 121-131 ◽  
Author(s):  
Julia Geiger ◽  
Amir A. Rahsepar ◽  
Kenichiro Suwa ◽  
Alex Powell ◽  
Ahmadreza Ghasemiesfe ◽  
...  

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