4-D Flow MRI-Based Computational Analysis of Blood Flow in Patient-Specific Aortic Dissection

Pirola, Selene; Guo, Baolei; Menichini, Claudia; Saitta, Simone; Fu, Weiguo; Dong, Zhihui; Xu, Xiao Yun

doi:10.1109/tbme.2019.2904885

Cited by 63 publications

(57 citation statements)

References 39 publications

(61 reference statements)

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“…In a recent study of 139 patients after TEVAR, chronic vs. acute DAD, rather than TBAD vs. rTAAD, impacted the procedure success. Nevertheless, since choice of indication in asymptomatic patients and TEVAR procedure remains challenging, the results may improve if 4D flow MRI data are used to predict post TEVAR hemodynamics and subsequently monitor the results . Thus, hemodynamic mapping throughout the stages of disease progression, as well as pre‐ and post‐surgery, will be an important next step in the understanding and improvement of risk‐stratification.…”

Section: Discussionmentioning

confidence: 99%

Parametric Hemodynamic 4D Flow MRI Maps for the Characterization of Chronic Thoracic Descending Aortic Dissection

Jarvis

Pruijssen

Son

et al. 2019

Magnetic Resonance Imaging

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Background: Systematic evaluation of complex flow in the true lumen and false lumen (TL, FL) is needed to better understand which patients with chronic descending aortic dissection (DAD) are predisposed to complications. Purpose: To develop quantitative hemodynamic maps from 4D flow MRI for evaluating TL and FL flow characteristics. Study Type: Retrospective. Population: In all, 20 DAD patients (age = 60 AE 11 years; 12 male) (six medically managed type B AD [TBAD], 14 repaired type A AD [rTAAD] now with ascending aortic graft [AAo] or elephant trunk [ET1] repair) and 21 age-matched controls (age = 59 AE 10 years; 13 male) were included. Field Strength/Sequence: 1.5T, 3T, 4D flow MRI. Assessment: 4D flow MRI was acquired in all subjects. Data analysis included 3D segmentation of TL and FL and voxelwise calculation of forward flow, reverse flow, flow stasis, and kinetic energy as quantitative hemodynamics maps. Statistical Tests: Analysis of variance (ANOVA) or Kruskal-Wallis tests were performed for comparing subject groups. Correlation and Bland-Altman analysis was performed for the interobserver study. Results: Patients with rTAAD presented with elevated TL reverse flow (AAo repair: P = 0.004, ET1: P = 0.018) and increased TL kinetic energy (AAo repair: P = 0.0002, ET1: P = 0.011) compared to controls. In addition, TL kinetic energy was increased vs. patients with TBAD (AAo repair: P = 0.021, ET1: P = 0.048). rTAAD was associated with higher FL kinetic energy and lower FL stasis compared to patients with TBAD (AAo repair: P = 0.002, ET1: P = 0.024 and AAo repair: P = 0.003, ET1: P = 0.048, respectively). Data Conclusion: Quantitative maps from 4D flow MRI demonstrated global and regional hemodynamic differences between DAD patients and controls. Patients with rTAAD vs. TBAD had significantly altered regional TL and FL hemodynamics. These findings indicate the potential of 4D flow MRI-derived hemodynamic maps to help better evaluate patients with DAD.

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Section: Discussionmentioning

confidence: 99%

Parametric Hemodynamic 4D Flow MRI Maps for the Characterization of Chronic Thoracic Descending Aortic Dissection

Jarvis

Pruijssen

Son

et al. 2019

Magnetic Resonance Imaging

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“…Geometries of P1, P2 and P2P used for simulation. The primary entry tear (PET) in each model is indicated, as well as planes on which pressure readings were taken (A1-5, B1-2 and C1-2) 3D IVPs were extracted from the 4D MRI data of P1 and P2 using an in-house MATLAB processing tool, developed in our previous studies (Pirola et al 2018(Pirola et al , 2019. From the results obtained with the 3D IVP simulation, TP and flat velocity profiles were derived using Ansys EnSight (v10.2) and an additional in-house MATLAB tool.…”

Section: Methodsmentioning

confidence: 99%

“…3 also includes the peak systolic velocity streamlines derived from the 4D MRI scan for P2. The equivalent 4D MRI data for P1 was previously reported by Pirola et al (2019). For validation of the computational methods used throughout this study, the streamlines obtained with 3D IVP for P1 and P2 were compared to their respective 4D MRI streamlines.…”

Section: Flow Patternsmentioning

confidence: 99%

The influence of inlet velocity profile on predicted flow in type B aortic dissection

Armour

Guo

Pirola

et al. 2020

Biomech Model Mechanobiol

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In order for computational fluid dynamics to provide quantitative parameters to aid in the clinical assessment of type B aortic dissection, the results must accurately mimic the hemodynamic environment within the aorta. The choice of inlet velocity profile (IVP) therefore is crucial; however, idealised profiles are often adopted, and the effect of IVP on hemodynamics in a dissected aorta is unclear. This study examined two scenarios with respect to the influence of IVP—using (a) patient-specific data in the form of a three-directional (3D), through-plane (TP) or flat IVP; and (b) non-patient-specific flow waveform. The results obtained from nine simulations using patient-specific data showed that all forms of IVP were able to reproduce global flow patterns as observed with 4D flow magnetic resonance imaging. Differences in maximum velocity and time-averaged wall shear stress near the primary entry tear were up to 3% and 6%, respectively, while pressure differences across the true and false lumen differed by up to 6%. More notable variations were found in regions of low wall shear stress when the primary entry tear was close to the left subclavian artery. The results obtained with non-patient-specific waveforms were markedly different. Throughout the aorta, a 25% reduction in stroke volume resulted in up to 28% and 35% reduction in velocity and wall shear stress, respectively, while the shape of flow waveform had a profound influence on the predicted pressure. The results of this study suggest that 3D, TP and flat IVPs all yield reasonably similar velocity and time-averaged wall shear stress results, but TP IVPs should be used where possible for better prediction of pressure. In the absence of patient-specific velocity data, effort should be made to acquire patient’s stroke volume and adjust the applied IVP accordingly.

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“…Geometrical accuracy has improved from the representation of only the dissected aorta with the upper branches 9 to the inclusion of the abdominal and visceral vessels. 21 Simplified 'static' outlet boundary conditions (BCs), such as constant pressure or prescribed flow splits, have been replaced by more physiologically-accurate 'dynamic' three-element Windkessel models (3WKs). 12 Recently, the limitation of the rigid wall assumption has also been overcome, with the implementation of fluid structure interaction (FSI) models able to simulate the motion of the aortic wall and IF.…”

Section: Introductionmentioning

confidence: 99%

“…Validation of patient-specific CFD simulations of AD is currently based on in vivo, 2D and 4D phase-contrast magnetic resonance imaging (PC-MRI) data. 21 However, these modalities, when used in a clinical setting, have poor resolution and are often subject to noise. Few studies have attempted to combine in vitro and in silico approaches for the study of AD hitherto.…”

Section: Introductionmentioning

confidence: 99%

A Combined In Vivo, In Vitro, In Silico Approach for Patient-Specific Haemodynamic Studies of Aortic Dissection

et al. 2020

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The optimal treatment of Type-B aortic dissection (AD) is still a subject of debate, with up to 50% of the cases developing late-term complications requiring invasive intervention. A better understanding of the patient-specific haemodynamic features of AD can provide useful insights on disease progression and support clinical management. In this work, a novel in vitro and in silico framework to perform personalised studies of AD, informed by non-invasive clinical data, is presented. A Type-B AD was investigated in silico using computational fluid dynamics (CFD) and in vitro by means of a state-of-the-art mock circulatory loop and particle image velocimetry (PIV). Both models not only reproduced the anatomical features of the patient, but also imposed physiologically-accurate and personalised boundary conditions. Experimental flow rate and pressure waveforms, as well as detailed velocity fields acquired via PIV, are extensively compared against numerical predictions at different locations in the aorta, showing excellent agreement. This work demonstrates how experimental and numerical tools can be developed in synergy to accurately reproduce patient-specific AD blood flow. The combined platform presented herein constitutes a powerful tool for advanced haemodynamic studies for a range of vascular conditions, allowing not only the validation of CFD models, but also clinical decision support, surgical planning as well as medical device innovation.

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4-D Flow MRI-Based Computational Analysis of Blood Flow in Patient-Specific Aortic Dissection

Cited by 63 publications

References 39 publications

Parametric Hemodynamic 4D Flow MRI Maps for the Characterization of Chronic Thoracic Descending Aortic Dissection

Parametric Hemodynamic 4D Flow MRI Maps for the Characterization of Chronic Thoracic Descending Aortic Dissection

The influence of inlet velocity profile on predicted flow in type B aortic dissection

A Combined In Vivo, In Vitro, In Silico Approach for Patient-Specific Haemodynamic Studies of Aortic Dissection

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