Four-dimensional-flow Magnetic Resonance Imaging of the Aortic Valve and Thoracic Aorta

Jamalidinan, Fatemehsadat; Hassanabad, Ali Fatehi; François, Christopher J.; García, Julio

doi:10.1016/j.rcl.2020.02.008

Cited by 18 publications

(12 citation statements)

References 56 publications

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“…BAV disease includes heterogeneous morphological phenotypes of fused cusps and raphe ( Sievers and Schmidtke, 2007 ) which can lead to different pathological and clinical outcomes ( Masri et al, 2017 ). At a population level, BAV is associated with increased risk of aortic dilation ( Jamalidinan et al, 2020 ), requiring surgical intervention in 30–50% of individuals ( Branchetti et al, 2014 ). Despite this, there is still variability in the clinical management guidelines ( Baumgartner et al, 2017 ; Borger et al, 2018 ) for BAV aortopathy and strategies among cardiovascular surgeons vary substantially ( Verma et al, 2013 ).…”

Section: Introductionmentioning

confidence: 99%

Hemodynamic Assessment in Bicuspid Aortic Valve Disease and Aortic Dilation: New Insights From Voxel-By-Voxel Analysis of Reverse Flow, Stasis, and Energetics

Geeraert

Jamalidinan

Burns

et al. 2022

Front. Bioeng. Biotechnol.

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Objectives: Clinical management decisions surrounding ascending aorta (AAo) dilation in bicuspid aortic valve (BAV) disease benefit from personalized predictive tools. 4D-flow MRI may provide patient-specific markers reflective of BAV-associated aortopathy. This study aims to explore novel 4D-flow MRI parametric voxel-by-voxel forward flow, reverse flow, kinetic energy and stasis in BAV disease. We hypothesize that novel parametric voxel-by-voxel markers will be associated with aortic dilation and referral for surgery and can enhance our understanding of BAV hemodynamics beyond standard metrics.Methods: A total of 96 subjects (73 BAV patients, 23 healthy controls) underwent MRI scan. Healthy controls had no known cardiovascular disease. Patients were clinically referred for AAo dilation assessment. Indexed diameters were obtained by dividing the aortic diameter by the patient’s body surface area. Patients were followed for the occurrence of aortic surgery. 4D-flow analysis was performed by a single observer in five regions: left ventricular outflow tract (LVOT), AAo, arch, proximal descending aorta (PDAo), and distal descending aorta (DDAo). In each region peak velocity, kinetic energy (KE), forward flow (FF), reverse flow (RF), and stasis were measured on a voxel-by-voxel basis. T-tests (or non-parametric equivalent) compared flow parameters between cohorts. Univariate and multivariate analyses explored associations between diameter and parametric voxel-by-voxel parameters.Results: Compared to controls, BAV patients showed reduced stasis (p < 0.01) and increased RF and FF (p < 0.01) throughout the aorta, and KE remained similar. In the AAo, indexed diameter correlated with age (R = 0.326, p = 0.01), FF (R = −0.648, p < 0.001), RF (R = −0.441, p < 0.001), and stasis (R = −0.288, p < 0.05). In multivariate analysis, FF showed a significant inverse association with AAo indexed diameter, independent of age. During a median 179 ± 180 days of follow-up, 23 patients (32%) required aortic surgery. Compared to patients not requiring surgery, they showed increased KE and peak velocity in the proximal aorta (p < 0.01), accompanied by increased RF and reduced stasis throughout the entire aorta (p < 0.01).Conclusion: Novel voxel-by-voxel reverse flow and stasis were altered in BAV patients and are associated with aortic dilation and surgical treatment.

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Section: Introductionmentioning

confidence: 99%

Hemodynamic Assessment in Bicuspid Aortic Valve Disease and Aortic Dilation: New Insights From Voxel-By-Voxel Analysis of Reverse Flow, Stasis, and Energetics

Geeraert

Jamalidinan

Burns

et al. 2022

Front. Bioeng. Biotechnol.

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“…4,5 Four-dimensional flow MRI (4 D flow MRI) is a novel imaging technique capable of measuring complex blood flow in the three principal directions and as a function of time, allowing for accurate quantification of blood flow in patients with VHD. 6,7 A particular benefit of 4 D flow MRI is the retrospective selection of analysis planes at any location within the 3 D data volume to perform blood flow quantification, although analysis planes are typically static and don't follow the motion of the heart valves. Valve tracking have showed to improve the characterization and quantification of eccentric regurgitation using 4 D flow MRI.…”

Section: Introductionmentioning

confidence: 99%

Aortic and mitral flow quantification using dynamic valve tracking and machine learning: Prospective study assessing static and dynamic plane repeatability, variability and agreement

García

Beckie

Hassanabad

et al. 2021

JRSM Cardiovascular Disease

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Background Blood flow is a crucial measurement in the assessment of heart valve disease. Time-resolved flow using magnetic resonance imaging (4 D flow MRI) can provide a comprehensive assessment of heart valve hemodynamics but it relies in manual plane analysis. In this study, we aimed to demonstrate the feasibility of automate the detection and tracking of aortic and mitral valve planes to assess blood flow from 4 D flow MRI. Methods In this prospective study, a total of n = 106 subjects were enrolled: 19 patients with mitral disease, 65 aortic disease patients and 22 healthy controls. Machine learning was employed to detect aortic and mitral location and motion in a cine three-chamber plane and a perpendicular projection was co-registered to the 4 D flow MRI dataset to quantify flow volume, regurgitant fraction, and a peak velocity. Static and dynamic plane association and agreement were evaluated. Intra- and inter-observer, and scan-rescan reproducibility were also assessed. Results Aortic regurgitant fraction was elevated in aortic valve disease patients as compared with controls and mitral valve disease patients ( p < 0.05). Similarly, mitral regurgitant fraction was higher in mitral valve patients ( p < 0.05). Both aortic and mitral total flow were high in aortic patients. Static and dynamic were good (r > 0.6, p < 0.005) for aortic total flow and peak velocity, and mitral peak velocity and regurgitant fraction. All measurements showed good inter- and intra-observer, and scan-rescan reproducibility. Conclusion We demonstrated that aortic and mitral hemodynamics can efficiently be quantified from 4 D flow MRI using assisted valve detection with machine learning.

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“…Therefore, we believe CMR is not yet a method of choice for hemodynamic severity assessment in clinical practice. There might be a promising role for CMR 4D-flow (82)(83)(84), which can assess not only velocities (with the potential advantage of less underestimation than standard 2D through plane phase-contrast CMR), but also pressure and energy losses along the stenosis and into the aorta, and assessment of shear stress. Four-dimensional flow, however, still remains experimental and is not easily applicable to routine clinical practice due to long post-processing times.…”

Section: Other Modalitiesmentioning

confidence: 99%

Multimodality Imaging for Discordant Low-Gradient Aortic Stenosis: Assessing the Valve and the Myocardium

Guzzetti

Annabi

Clavel

2020

Front. Cardiovasc. Med.

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Aortic stenosis (AS) is a disease of the valve and the myocardium. A correct assessment of the valve disease severity is key to define the need for aortic valve replacement (AVR), but a better understanding of the myocardial consequences of the increased afterload is paramount to optimize the timing of the intervention. Transthoracic echocardiography remains the cornerstone of AS assessment, as it is universally available, and it allows a comprehensive structural and hemodynamic evaluation of both the aortic valve and the rest of the heart. However, it may not be sufficient as a significant proportion of patients with severe AS presents with discordant grading (i.e., an AVA ≤ 1 cm2 and a mean gradient <40 mmHg) which raises uncertainty about the true severity of AS and the need for AVR. Several imaging modalities (transesophageal or stress echocardiography, computed tomography, cardiovascular magnetic resonance, positron emission tomography) exist that allow a detailed assessment of the stenotic aortic valve and the myocardial remodeling response. This review aims to provide an updated overview of these multimodality imaging techniques and seeks to highlight a practical approach to help clinical decision making in the challenging group of patients with discordant low-gradient AS.

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Four-dimensional-flow Magnetic Resonance Imaging of the Aortic Valve and Thoracic Aorta

Cited by 18 publications

References 56 publications

Hemodynamic Assessment in Bicuspid Aortic Valve Disease and Aortic Dilation: New Insights From Voxel-By-Voxel Analysis of Reverse Flow, Stasis, and Energetics

Hemodynamic Assessment in Bicuspid Aortic Valve Disease and Aortic Dilation: New Insights From Voxel-By-Voxel Analysis of Reverse Flow, Stasis, and Energetics

Aortic and mitral flow quantification using dynamic valve tracking and machine learning: Prospective study assessing static and dynamic plane repeatability, variability and agreement

Multimodality Imaging for Discordant Low-Gradient Aortic Stenosis: Assessing the Valve and the Myocardium

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