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Iwata K, Sekine T, Matsuda J, Tachi M, Imori Y, Amano Y, Ando T, Obara M, Crelier G, Ogawa M, Takano H, Kumita S. Measurement of Turbulent Kinetic Energy in Hypertrophic Cardiomyopathy Using Triple-velocity Encoding 4D Flow MR Imaging. Magn Reson Med Sci 2024; 23:39-48. [PMID: 36517010 PMCID: PMC10838723 DOI: 10.2463/mrms.mp.2022-0051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 10/10/2022] [Indexed: 01/05/2024] Open
Abstract
PURPOSE The turbulent kinetic energy (TKE) estimation based on 4D flow MRI has been currently developed and can be used to estimate the pressure gradient. The objective of this study was to validate the clinical value of 4D flow-based TKE measurement in patients with hypertrophic cardiomyopathy (HCM). METHODS From April 2018 to March 2019, we recruited 28 patients with HCM. Based on echocardiography, they were divided into obstructed HCM (HOCM) and non-obstructed HCM (HNCM). Triple-velocity encoding 4D flow MRI was performed. The volume-of-interest from the left ventricle to the aortic arch was drawn semi-automatically. We defined peak turbulent kinetic energy (TKEpeak) as the highest TKE phase in all cardiac phases. RESULTS TKEpeak was significantly higher in HOCM than in HNCM (14.83 ± 3.91 vs. 7.11 ± 3.60 mJ, P < 0.001). TKEpeak was significantly higher in patients with systolic anterior movement (SAM) than in those without SAM (15.60 ± 3.96 vs. 7.44 ± 3.29 mJ, P < 0.001). Left ventricular (LV) mass increased proportionally with TKEpeak (P = 0.012, r = 0.466). When only the asymptomatic patients were extracted, a stronger correlation was observed (P = 0.001, r = 0.842). CONCLUSION TKE measurement based on 4D flow MRI can detect the flow alteration induced by systolic flow jet and LV outflow tract geometry, such as SAM in patients with HOCM. The elevated TKE is correlated with increasing LV mass. This indicates that increasing cardiac load, by pressure loss due to turbulence, induces progression of LV hypertrophy, which leads to a worse prognosis.
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Affiliation(s)
- Kotomi Iwata
- Department of Radiology, Nippon Medical School, Tokyo, Japan
- Both Kotomi Iwata and Tetsuro Sekine are listed as the double-first author because each of them had the same contribution in this study
| | - Tetsuro Sekine
- Department of Radiology, Nippon Medical School Musashi Kosugi Hospital, Kawasaki, Kanagawa, Japan
- Both Kotomi Iwata and Tetsuro Sekine are listed as the double-first author because each of them had the same contribution in this study
| | - Junya Matsuda
- Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan
| | - Masaki Tachi
- Department of Radiology, Nippon Medical School, Tokyo, Japan
| | - Yoichi Imori
- Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan
| | - Yasuo Amano
- Department of Radiology, Nihon University School of Medicine, Tokyo, Japan
| | - Takahiro Ando
- Department of Radiology, Nippon Medical School, Tokyo, Japan
| | | | | | - Masashi Ogawa
- Department of Radiology, Nippon Medical School, Tokyo, Japan
| | - Hitoshi Takano
- Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan
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Gill H, Fernandes J, Chehab O, Prendergast B, Redwood S, Chiribiri A, Nordsletten D, Rajani R, Lamata P. Evaluation of aortic stenosis: From Bernoulli and Doppler to Navier-Stokes. Trends Cardiovasc Med 2023; 33:32-43. [PMID: 34920129 DOI: 10.1016/j.tcm.2021.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 12/07/2021] [Accepted: 12/07/2021] [Indexed: 02/01/2023]
Abstract
Uni-dimensional Doppler echocardiography data provide the mainstay of quantative assessment of aortic stenosis, with the transvalvular pressure drop a key indicator of haemodynamic burden. Sophisticated methods of obtaining velocity data, combined with improved computational analysis, are facilitating increasingly robust and reproducible measurement. Imaging modalities which permit acquisition of three-dimensional blood velocity vector fields enable angle-independent valve interrogation and calculation of enhanced measures of the transvalvular pressure drop. This manuscript clarifies the fundamental principles of physics that underpin the evaluation of aortic stenosis and explores modern techniques that may provide more accurate means to grade aortic stenosis and inform appropriate management.
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Affiliation(s)
- Harminder Gill
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.
| | - Joao Fernandes
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Omar Chehab
- Cardiology Department, Guy's and St. Thomas's Hospital NHS Foundation Trust, London, UK
| | - Bernard Prendergast
- Cardiology Department, Guy's and St. Thomas's Hospital NHS Foundation Trust, London, UK
| | - Simon Redwood
- Cardiology Department, Guy's and St. Thomas's Hospital NHS Foundation Trust, London, UK
| | - Amedeo Chiribiri
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - David Nordsletten
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK; Department of Surgery and Biomedical Engineering, University of Michigan, 2800 Plymouth Rd, 48109, Ann Arbor, MI, USA
| | - Ronak Rajani
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK; Cardiology Department, Guy's and St. Thomas's Hospital NHS Foundation Trust, London, UK
| | - Pablo Lamata
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
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Peper ES, van Ooij P, Jung B, Huber A, Gräni C, Bastiaansen JAM. Advances in machine learning applications for cardiovascular 4D flow MRI. Front Cardiovasc Med 2022; 9:1052068. [PMID: 36568555 PMCID: PMC9780299 DOI: 10.3389/fcvm.2022.1052068] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 11/22/2022] [Indexed: 12/13/2022] Open
Abstract
Four-dimensional flow magnetic resonance imaging (MRI) has evolved as a non-invasive imaging technique to visualize and quantify blood flow in the heart and vessels. Hemodynamic parameters derived from 4D flow MRI, such as net flow and peak velocities, but also kinetic energy, turbulent kinetic energy, viscous energy loss, and wall shear stress have shown to be of diagnostic relevance for cardiovascular diseases. 4D flow MRI, however, has several limitations. Its long acquisition times and its limited spatio-temporal resolutions lead to inaccuracies in velocity measurements in small and low-flow vessels and near the vessel wall. Additionally, 4D flow MRI requires long post-processing times, since inaccuracies due to the measurement process need to be corrected for and parameter quantification requires 2D and 3D contour drawing. Several machine learning (ML) techniques have been proposed to overcome these limitations. Existing scan acceleration methods have been extended using ML for image reconstruction and ML based super-resolution methods have been used to assimilate high-resolution computational fluid dynamic simulations and 4D flow MRI, which leads to more realistic velocity results. ML efforts have also focused on the automation of other post-processing steps, by learning phase corrections and anti-aliasing. To automate contour drawing and 3D segmentation, networks such as the U-Net have been widely applied. This review summarizes the latest ML advances in 4D flow MRI with a focus on technical aspects and applications. It is divided into the current status of fast and accurate 4D flow MRI data generation, ML based post-processing tools for phase correction and vessel delineation and the statistical evaluation of blood flow.
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Affiliation(s)
- Eva S. Peper
- Department of Diagnostic, Interventional and Pediatric Radiology (DIPR), Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland,Translational Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, Bern, Switzerland,*Correspondence: Eva S. Peper,
| | - Pim van Ooij
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Amsterdam, Netherlands,Department of Pediatric Cardiology, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, Netherlands
| | - Bernd Jung
- Department of Diagnostic, Interventional and Pediatric Radiology (DIPR), Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland,Translational Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, Bern, Switzerland
| | - Adrian Huber
- Department of Diagnostic, Interventional and Pediatric Radiology (DIPR), Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Christoph Gräni
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Jessica A. M. Bastiaansen
- Department of Diagnostic, Interventional and Pediatric Radiology (DIPR), Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland,Translational Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, Bern, Switzerland
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Dirix P, Buoso S, Peper ES, Kozerke S. Synthesis of patient-specific multipoint 4D flow MRI data of turbulent aortic flow downstream of stenotic valves. Sci Rep 2022; 12:16004. [PMID: 36163357 PMCID: PMC9513106 DOI: 10.1038/s41598-022-20121-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 09/08/2022] [Indexed: 11/09/2022] Open
Abstract
We propose to synthesize patient-specific 4D flow MRI datasets of turbulent flow paired with ground truth flow data to support training of inference methods. Turbulent blood flow is computed based on the Navier-Stokes equations with moving domains using realistic boundary conditions for aortic shapes, wall displacements and inlet velocities obtained from patient data. From the simulated flow, synthetic multipoint 4D flow MRI data is generated with user-defined spatiotemporal resolutions and reconstructed with a Bayesian approach to compute time-varying velocity and turbulence maps. For MRI data synthesis, a fixed hypothetical scan time budget is assumed and accordingly, changes to spatial resolution and time averaging result in corresponding scaling of signal-to-noise ratios (SNR). In this work, we focused on aortic stenotic flow and quantification of turbulent kinetic energy (TKE). Our results show that for spatial resolutions of 1.5 and 2.5 mm and time averaging of 5 ms as encountered in 4D flow MRI in practice, peak total turbulent kinetic energy downstream of a 50, 75 and 90% stenosis is overestimated by as much as 23, 15 and 14% (1.5 mm) and 38, 24 and 23% (2.5 mm), demonstrating the importance of paired ground truth and 4D flow MRI data for assessing accuracy and precision of turbulent flow inference using 4D flow MRI exams.
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Affiliation(s)
- Pietro Dirix
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.
| | - Stefano Buoso
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Eva S Peper
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
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McLennan D, Schäfer M, Barker AJ, Mitchell MB, Ing RJ, Browne LP, Ivy DD, Morgan GJ. Abnormal flow conduction through pulmonary arteries is associated with right ventricular volume and function in patients with repaired tetralogy of Fallot: does flow quality affect afterload? Eur Radiol 2022; 33:302-311. [DOI: 10.1007/s00330-022-09017-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 05/27/2022] [Accepted: 07/04/2022] [Indexed: 11/04/2022]
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Hoeijmakers MJMM, Morgenthaler V, Rutten MCM, van de Vosse FN. Scale-Resolving Simulations of Steady and Pulsatile Flow Through Healthy and Stenotic Heart Valves. J Biomech Eng 2022; 144:1119643. [PMID: 34529056 DOI: 10.1115/1.4052459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Indexed: 11/08/2022]
Abstract
Blood-flow downstream of stenotic and healthy aortic valves exhibits intermittent random fluctuations in the velocity field which are associated with turbulence. Such flows warrant the use of computationally demanding scale-resolving models. The aim of this work was to compute and quantify this turbulent flow in healthy and stenotic heart valves for steady and pulsatile flow conditions. Large eddy simulations (LESs) and Reynolds-averaged Navier-Stokes (RANS) simulations were used to compute the flow field at inlet Reynolds numbers of 2700 and 5400 for valves with an opening area of 70 mm2 and 175 mm2 and their projected orifice-plate type counterparts. Power spectra and turbulent kinetic energy were quantified on the centerline. Projected geometries exhibited an increased pressure-drop (>90%) and elevated turbulent kinetic energy levels (>147%). Turbulence production was an order of magnitude higher in stenotic heart valves compared to healthy valves. Pulsatile flow stabilizes flow in the acceleration phase, whereas onset of deceleration triggered (healthy valve) or amplified (stenotic valve) turbulence. Simplification of the aortic valve by projecting the orifice area should be avoided in computational fluid dynamics (CFD). RANS simulations may be used to predict the transvalvular pressure-drop, but scale-resolving models are recommended when detailed information of the flow field is required.
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Affiliation(s)
- M J M M Hoeijmakers
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven 5600 MB The Netherlands; Ansys Inc., Villeurbanne 69100, France
| | | | - M C M Rutten
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven 5600 MB, The Netherlands
| | - F N van de Vosse
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven 5600 MB, The Netherlands
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7
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de Vecchi A, Faraci A, Fernandes JF, Marlevi D, Bellsham-Revell H, Hussain T, Laji N, Ruijsink B, Wong J, Razavi R, Anderson D, Salih C, Pushparajah K, Nordsletten D, Lamata P. Unlocking the Non-invasive Assessment of Conduit and Reservoir Function in the Aorta. J Cardiovasc Transl Res 2022; 15:1075-1085. [PMID: 35199256 PMCID: PMC9622527 DOI: 10.1007/s12265-022-10221-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 02/14/2022] [Indexed: 11/06/2022]
Abstract
Aortic surgeries in congenital conditions, such as hypoplastic left heart syndrome (HLHS), aim to restore and maintain the conduit and reservoir functions of the aorta. We proposed a method to assess these two functions based on 4D flow MRI, and we applied it to study the aorta in pre-Fontan HLHS. Ten pre-Fontan HLHS patients and six age-matched controls were studied to derive the advective pressure difference and viscous dissipation for conduit function, and pulse wave velocity and elastic modulus for reservoir function. The reconstructed neo-aorta in HLHS subjects achieved a good conduit function at a cost of an impaired reservoir function (69.7% increase of elastic modulus). The native descending HLHS aorta displayed enhanced reservoir (elastic modulus being 18.4% smaller) but impaired conduit function (three-fold increase in peak advection). A non-invasive and comprehensive assessment of aortic conduit and reservoir functions is feasible and has potentially clinical relevance in congenital vascular conditions.
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Affiliation(s)
- Adelaide de Vecchi
- School of Biomedical Engineering and Imaging Sciences, King's College London, 5th Floor Becket House, Lambeth Palace Road, London, SE1 7EU, UK
| | - Alessandro Faraci
- School of Biomedical Engineering and Imaging Sciences, King's College London, 5th Floor Becket House, Lambeth Palace Road, London, SE1 7EU, UK
| | - Joao Filipe Fernandes
- School of Biomedical Engineering and Imaging Sciences, King's College London, 5th Floor Becket House, Lambeth Palace Road, London, SE1 7EU, UK
| | - David Marlevi
- Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Hannah Bellsham-Revell
- Department of Congenital Heart Disease, Evelina London Children's Hospital, Guy's & St Thomas' Hospitals, London, SE1 7EH, UK
| | - Tarique Hussain
- Pediatric Cardiology, UT Southwestern, Children's Medical Center Dallas, 1935 Medical District Dr, Dallas, TX, 75235, USA
| | - Nidhin Laji
- School of Biomedical Engineering and Imaging Sciences, King's College London, 5th Floor Becket House, Lambeth Palace Road, London, SE1 7EU, UK
| | - Bram Ruijsink
- School of Biomedical Engineering and Imaging Sciences, King's College London, 5th Floor Becket House, Lambeth Palace Road, London, SE1 7EU, UK
| | - James Wong
- School of Biomedical Engineering and Imaging Sciences, King's College London, 5th Floor Becket House, Lambeth Palace Road, London, SE1 7EU, UK
| | - Reza Razavi
- School of Biomedical Engineering and Imaging Sciences, King's College London, 5th Floor Becket House, Lambeth Palace Road, London, SE1 7EU, UK
| | - David Anderson
- Department of Congenital Heart Disease, Evelina London Children's Hospital, Guy's & St Thomas' Hospitals, London, SE1 7EH, UK
| | - Caner Salih
- Department of Congenital Heart Disease, Evelina London Children's Hospital, Guy's & St Thomas' Hospitals, London, SE1 7EH, UK
| | - Kuberan Pushparajah
- School of Biomedical Engineering and Imaging Sciences, King's College London, 5th Floor Becket House, Lambeth Palace Road, London, SE1 7EU, UK
| | - David Nordsletten
- School of Biomedical Engineering and Imaging Sciences, King's College London, 5th Floor Becket House, Lambeth Palace Road, London, SE1 7EU, UK.,Department of Biomedical Engineering and Cardiac Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Pablo Lamata
- School of Biomedical Engineering and Imaging Sciences, King's College London, 5th Floor Becket House, Lambeth Palace Road, London, SE1 7EU, UK.
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Itatani K, Sekine T, Yamagishi M, Maeda Y, Higashitani N, Miyazaki S, Matsuda J, Takehara Y. Hemodynamic Parameters for Cardiovascular System in 4D Flow MRI: Mathematical Definition and Clinical Applications. Magn Reson Med Sci 2022; 21:380-399. [PMID: 35173116 DOI: 10.2463/mrms.rev.2021-0097] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Blood flow imaging becomes an emerging trend in cardiology with the recent progress in computer technology. It not only visualizes colorful flow velocity streamlines but also quantifies the mechanical stress on cardiovascular structures; thus, it can provide the detailed inspections of the pathophysiology of diseases and predict the prognosis of cardiovascular functions. Clinical applications include the comprehensive assessment of hemodynamics and cardiac functions in echocardiography vector flow mapping (VFM), 4D flow MRI, and surgical planning as a simulation medicine in computational fluid dynamics (CFD).For evaluation of the hemodynamics, novel mathematically derived parameters obtained using measured velocity distributions are essential. Among them, the traditional and typical parameters are wall shear stress (WSS) and its related parameters. These parameters indicate the mechanical damages to endothelial cells, resulting in degenerative intimal change in vascular diseases. Apart from WSS, there are abundant parameters that describe the strength of the vortical and/or helical flow patterns. For instance, vorticity, enstrophy, and circulation indicate the rotating flow strength or power of 2D vortical flows. In addition, helicity, which is defined as the cross-linking number of the vortex filaments, indicates the 3D helical flow strength and adequately describes the turbulent flow in the aortic root in cases with complicated anatomies. For the description of turbulence caused by the diseased flow, there exist two types of parameters based on completely different concepts, namely: energy loss (EL) and turbulent kinetic energy (TKE). EL is the dissipated energy with blood viscosity and evaluates the cardiac workload related to the prognosis of heart failure. TKE describes the fluctuation in kinetic energy during turbulence, which describes the severity of the diseases that cause jet flow. These parameters are based on intuitive and clear physiological concepts, and are suitable for in vivo flow measurements using inner velocity profiles.
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Affiliation(s)
- Keiichi Itatani
- Department of Cardiovascular Surgery, Osaka City University.,Cardio Flow Design Inc
| | - Tetsuro Sekine
- Department of Radiology, Nippon Medical School Musashi Kosugi Hospital
| | - Masaaki Yamagishi
- Department of Pediatric Cardiovascular Surgery, Kyoto Prefectural University of Medicine
| | - Yoshinobu Maeda
- Department of Pediatric Cardiovascular Surgery, Kyoto Prefectural University of Medicine
| | - Norika Higashitani
- Cardio Flow Design Inc.,Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine
| | | | - Junya Matsuda
- Department of Cardiovascular Medicine, Nippon Medical School
| | - Yasuo Takehara
- Department of Fundamental Development for Advanced Low Invasive Diagnostic Imaging, Nagoya university Graduate School of Medicine
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Dillinger H, McGrath C, Guenthner C, Kozerke S. Fundamentals of turbulent flow spectrum imaging. Magn Reson Med 2021; 87:1231-1249. [PMID: 34786764 PMCID: PMC9299145 DOI: 10.1002/mrm.29001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 08/12/2021] [Accepted: 08/18/2021] [Indexed: 12/13/2022]
Abstract
PURPOSE To introduce a mathematical framework and in-silico validation of turbulent flow spectrum imaging (TFSI) of stenotic flow using phase-contrast MRI, evaluate systematic errors in quantitative turbulence parameter estimation, and propose a novel method for probing the Lagrangian velocity spectra of turbulent flows. THEORY AND METHODS The spectral response of velocity-encoding gradients is derived theoretically and linked to turbulence parameter estimation including the velocity autocorrelation function spectrum. Using a phase-contrast MRI simulation framework, the encoding properties of bipolar gradient waveforms with identical first gradient moments but different duration are investigated on turbulent flow data of defined characteristics as derived from computational fluid dynamics. Based on theoretical insights, an approach using velocity-compensated gradient waveforms is proposed to specifically probe desired ranges of the velocity autocorrelation function spectrum with increased accuracy. RESULTS Practical velocity-encoding gradients exhibit limited encoding power of typical turbulent flow spectra, resulting in up to 50% systematic underestimation of intravoxel SD values. Depending on the turbulence level in fluids, the error due to a single encoding gradient spectral response can vary by 20%. When using tailored velocity-compensated gradients, improved quantification of the Lagrangian velocity spectrum on a voxel-by-voxel basis is achieved and used for quantitative correction of intravoxel SD values estimated with velocity-encoding gradients. CONCLUSION To address systematic underestimation of turbulence parameters using bipolar velocity-encoding gradients in phase-contrast MRI of stenotic flows with short correlation times, tailored velocity-compensated gradients are proposed to improve quantitative mapping of turbulent blood flow characteristics.
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Affiliation(s)
- Hannes Dillinger
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Charles McGrath
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Christian Guenthner
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
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High-degree Norwood neoaortic tapering is associated with abnormal flow conduction and elevated flow-mediated energy loss. J Thorac Cardiovasc Surg 2021; 162:1791-1804. [PMID: 33653609 DOI: 10.1016/j.jtcvs.2021.01.111] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 01/14/2021] [Accepted: 01/25/2021] [Indexed: 11/20/2022]
Abstract
OBJECTIVE The Norwood neoaortic arch biomechanical properties are abnormal due to reduced vessel wall compliance and abnormal geometry. Others have previously described neoaortic geometric distortion by the degree of diameter reduction (tapering) and associated this with mismatched ventricular-neoaortic coupling, abnormal flow hemodynamic parameters, and worse patient outcome. Our purposes were to investigate the influence of neoaortic tapering (ie, diameter reduction) on flow-mediated viscous energy loss (EL') in post-Norwood palliated hypoplastic left heart syndrome patients, and correlate flow-geometry with single ventricle power generation. METHODS Twenty-six palliated hypoplastic left heart syndrome patients underwent comprehensive cardiac evaluation with 4-dimensional-flow magnetic resonance imaging. Patients were grouped into high- (group H, n = 13) and low- (group L, n = 13) degree neoaortic tapering using the median cutoff value of neoaortic diameter variance. EL' was calculated along standardized segments using 4-dimensional-flow magnetic resonance imaging. Flow-mediated power loss as a percentage of total power generated by the single ventricle was determined. RESULTS Group H had a higher prevalence of abnormal recirculating flow in the neoaorta and elevated neoaortic EL' in the ascending aorta (1.0 vs 0.6 mW; P = .004). Group H EL' was increased across the entire thoracic aorta (2.6 vs 1.3 mW; P = .002) and accounted for 0.7% of generated ventricular power versus 0.3% in group L (P = .024). EL' directly correlated with the degree of ascending aortic dilation (R = 0.49; P = .012). CONCLUSIONS Patients with high degree neoaortic tapering have more perturbed flow through the neoaorta and increased EL'. Flow-mediated energy loss due to abnormal flow represents irreversibly wasted power generated by the single right ventricle. In patients with high-degree neoaortic tapering, EL' was more than 2-fold greater than low-degree tapering patients. These data suggest that oversizing the Norwood neoaortic reconstruction should be avoided and that patients with distorted neoaortic geometry may warrant increased surveillance for single-ventricle deterioration.
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Iwata K, Sekine T, Tanaka I, Ando T, Orita E. Turbulent Kinetic Energy Is Different from Viscous Energy Loss. Radiographics 2020; 40:2142-2144. [PMID: 33136486 DOI: 10.1148/rg.2020200177] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kotomi Iwata
- Department of Radiology, Nippon Medical School, Tokyo, Japan; Department of Radiology, Nippon Medical School Musashikosugi Hospital, 1-396 Kosugicho, Nakaharaku, Kawasaki, Kanagawa 211-8533, Japan (T.S.)
| | - Tetsuro Sekine
- Department of Radiology, Nippon Medical School, Tokyo, Japan; Department of Radiology, Nippon Medical School Musashikosugi Hospital, 1-396 Kosugicho, Nakaharaku, Kawasaki, Kanagawa 211-8533, Japan (T.S.)
| | - Izumi Tanaka
- Department of Radiology, Nippon Medical School, Tokyo, Japan; Department of Radiology, Nippon Medical School Musashikosugi Hospital, 1-396 Kosugicho, Nakaharaku, Kawasaki, Kanagawa 211-8533, Japan (T.S.)
| | - Takahiro Ando
- Department of Radiology, Nippon Medical School, Tokyo, Japan; Department of Radiology, Nippon Medical School Musashikosugi Hospital, 1-396 Kosugicho, Nakaharaku, Kawasaki, Kanagawa 211-8533, Japan (T.S.)
| | - Erika Orita
- Department of Radiology, Nippon Medical School, Tokyo, Japan; Department of Radiology, Nippon Medical School Musashikosugi Hospital, 1-396 Kosugicho, Nakaharaku, Kawasaki, Kanagawa 211-8533, Japan (T.S.)
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12
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Di Labbio G, Ben Assa E, Kadem L. Experimental Investigation of the Effect of Heart Rate on Flow in the Left Ventricle in Health and Disease-Aortic Valve Regurgitation. J Biomech Eng 2020; 142:051005. [PMID: 31701119 DOI: 10.1115/1.4045400] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Indexed: 11/08/2022]
Abstract
There is much debate in the literature surrounding the effects of heart rate on aortic regurgitation (AR). Despite the contradictory information, it is still widely believed that an increase in heart rate is beneficial due to the disproportionate shortening of the duration of diastole relative to systole, permitting less time for the left ventricle to fill from regurgitation. This in vitro work investigates how a change in heart rate affects the left ventricular fluid dynamics in the absence and presence of acute AR. The experiments are performed on a novel double-activation left heart simulator previously used for the study of chronic AR. The intraventricular velocity fields are acquired via time-resolved planar particle image velocimetry (PIV) in a clinically relevant plane. Considering fluid dynamic factors, an increase in heart rate was observed to have a limited benefit in the case of mild AR and a detrimental effect for more severe AR. With increasing heart rate, mild AR was associated with a decrease in regurgitant volume, a negligible change in regurgitant volume per diastolic second, and a limited reduction in the fraction of retained regurgitant inflow. More severe AR was accompanied by an increase in both regurgitant volume and the fraction of retained regurgitant inflow, implying a less effective pumping efficiency and a longer relative residence time of blood in the ventricle. Globally, the left ventricle's capacity to compensate for the increase in energy dissipation associated with an increase in heart rate diminishes considerably with severity, a phenomenon which may be exploited further as a method of noninvasive assessment of the severity of AR. These findings may affect the clinical belief that tachycardia is preferred in acute AR and should be investigated further in the clinical setting.
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Affiliation(s)
- Giuseppe Di Labbio
- Department of Mechanical, Industrial & Aerospace Engineering, Concordia University, 1455 Blvd. De Maisonneuve W., Montréal, QC H3G 1M8, Canada
| | - Eyal Ben Assa
- Cardiology Division, Sackler Faculty of Medicine, Tel Aviv Sourasky Medical Center, Tel Aviv 6997801, Israel; Institute for Medical Engineering and Science, Massachusetts Institute of Technology,77 Massachusetts Avenue, Cambridge, MA 02139
| | - Lyes Kadem
- Department of Mechanical, Industrial & Aerospace Engineering, Concordia University, 1455 Blvd. De Maisonneuve W., Montréal, QC H3G 1M8, Canada
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13
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A parametric model for studying the aorta hemodynamics by means of the computational fluid dynamics. J Biomech 2020; 103:109691. [PMID: 32147240 DOI: 10.1016/j.jbiomech.2020.109691] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 01/20/2020] [Accepted: 02/21/2020] [Indexed: 11/23/2022]
Abstract
Perturbed aorta hemodynamics, as for the carotid and the coronary artery, has been identified as potential predicting factor for cardiovascular diseases. In this study, we propose a parametric study based on the computational fluid dynamics with the aim of providing information regarding aortic disease. In particular, the blood flow inside a parametrized aortic arch is computed as a function of morphological changes of baseline aorta geometry. Flow patterns, wall shear stress, time average wall shear stress and oscillatory shear index were calculated during the cardiac cycle. The influence of geometrical changes on the hemodynamics and on these variables was evaluated. The results suggest that the distance between inflow and aortic arch and the angle between aortic arch and descending trunk are the most influencing parameters regarding the WSS-related indices while the effect of the inlet diameter seems limited. In particular, an increase of the aforementioned distance produces a reduction of the spatial distribution of the higher values of the time average wall shear stress and of the oscillatory shear index independently on the other two parameters while an increase of the angle produce an opposite effect. Moreover, as expected, the analysis of the wall shear stress descriptors suggests that the inlet diameter influences only the flow intensity. As conclusion, the proposed parametric study can be used to evaluate the aorta hemodynamics and could be also applied in the future, for analyzing pathological cases and virtual situations, such as pre- and/or post-operative cardiovascular surgical states that present enhanced changes in the aorta morphology yet promoting important variations on the considered indexes.
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14
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Marlevi D, Ha H, Dillon-Murphy D, Fernandes JF, Fovargue D, Colarieti-Tosti M, Larsson M, Lamata P, Figueroa CA, Ebbers T, Nordsletten DA. Non-invasive estimation of relative pressure in turbulent flow using virtual work-energy. Med Image Anal 2020; 60:101627. [PMID: 31865280 DOI: 10.1016/j.media.2019.101627] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 10/11/2019] [Accepted: 12/05/2019] [Indexed: 10/25/2022]
Abstract
Vascular pressure differences are established risk markers for a number of cardiovascular diseases. Relative pressures are, however, often driven by turbulence-induced flow fluctuations, where conventional non-invasive methods may yield inaccurate results. Recently, we proposed a novel method for non-turbulent flows, νWERP, utilizing the concept of virtual work-energy to accurately probe relative pressure through complex branching vasculature. Here, we present an extension of this approach for turbulent flows: νWERP-t. We present a theoretical method derivation based on flow covariance, quantifying the impact of flow fluctuations on relative pressure. νWERP-t is tested on a set of in-vitro stenotic flow phantoms with data acquired by 4D flow MRI with six-directional flow encoding, as well as on a patient-specific in-silico model of an acute aortic dissection. Over all tests νWERP-t shows improved accuracy over alternative energy-based approaches, with excellent recovery of estimated relative pressures. In particular, the use of a guaranteed divergence-free virtual field improves accuracy in cases where turbulent flows skew the apparent divergence of the acquired field. With the original νWERP allowing for assessment of relative pressure into previously inaccessible vasculatures, the extended νWERP-t further enlarges the method's clinical scope, underlining its potential as a novel tool for assessing relative pressure in-vivo.
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Affiliation(s)
- David Marlevi
- Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Hälsovägen 11, 14152, Huddinge, Sweden; Department of Clinical Sciences, Karolinska Institutet, Danderyds sjukhus, Mörbygårdsvägen, Danderyd, 18288, Sweden.
| | - Hojin Ha
- Department of Medical and Health Sciences and Center for Medical Image Science and Visualization (CMIV), Linköping Unversity, Linköping, SE-58185, Sweden; Department of Mechanical and Biomedical Engineering, Kangwon National University, Chuncheon, 24341, Republic of Korea.
| | - Desmond Dillon-Murphy
- School of Biomedical Engineering and Imaging Sciences, The Rayne Institute, King's College London, London, SE1 7EH, United Kingdom.
| | - Joao F Fernandes
- School of Biomedical Engineering and Imaging Sciences, The Rayne Institute, King's College London, London, SE1 7EH, United Kingdom.
| | - Daniel Fovargue
- School of Biomedical Engineering and Imaging Sciences, The Rayne Institute, King's College London, London, SE1 7EH, United Kingdom.
| | - Massimiliano Colarieti-Tosti
- Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Hälsovägen 11, 14152, Huddinge, Sweden.
| | - Matilda Larsson
- Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Hälsovägen 11, 14152, Huddinge, Sweden.
| | - Pablo Lamata
- School of Biomedical Engineering and Imaging Sciences, The Rayne Institute, King's College London, London, SE1 7EH, United Kingdom.
| | - C Alberto Figueroa
- School of Biomedical Engineering and Imaging Sciences, The Rayne Institute, King's College London, London, SE1 7EH, United Kingdom; Department of Surgery and Biomedical Engineering, University of Michigan, 2800 Plymouth Rd, 48109, Ann Arbor, MI, USA.
| | - Tino Ebbers
- Department of Medical and Health Sciences and Center for Medical Image Science and Visualization (CMIV), Linköping Unversity, Linköping, SE-58185, Sweden.
| | - David A Nordsletten
- School of Biomedical Engineering and Imaging Sciences, The Rayne Institute, King's College London, London, SE1 7EH, United Kingdom; Department of Surgery and Biomedical Engineering, University of Michigan, 2800 Plymouth Rd, 48109, Ann Arbor, MI, USA
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15
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5D Flow Tensor MRI to Efficiently Map Reynolds Stresses of Aortic Blood Flow In-Vivo. Sci Rep 2019; 9:18794. [PMID: 31827204 PMCID: PMC6906513 DOI: 10.1038/s41598-019-55353-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 11/23/2019] [Indexed: 11/23/2022] Open
Abstract
Diseased heart valves perturb normal blood flow with a range of hemodynamic and pathologic consequences. In order to better stratify patients with heart valve disease, a comprehensive characterization of blood flow including turbulent contributions is desired. In this work we present a framework to efficiently quantify velocities and Reynolds stresses in the aorta in-vivo. Using a highly undersampled 5D Flow MRI acquisition scheme with locally low-rank image reconstruction, multipoint flow tensor encoding in short and predictable scan times becomes feasible (here, 10 minutes), enabling incorporation of the protocol into clinical workflows. Based on computer simulations, a 19-point 5D Flow Tensor MRI encoding approach is proposed. It is demonstrated that, for in-vivo resolution and signal-to-noise ratios, sufficient accuracy and precision of velocity and turbulent shear stress quantification is achievable. In-vivo proof of concept is demonstrated on patients with a bio-prosthetic heart valve and healthy controls. Results demonstrate that aortic turbulent shear stresses and turbulent kinetic energy are elevated in the patients compared to the healthy subjects. Based on these data, it is concluded that 5D Flow Tensor MRI holds promise to provide comprehensive flow assessment in patients with heart valve diseases.
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16
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Walheim J, Gotschy A, Kozerke S. On the limitations of partial Fourier acquisition in phase-contrast MRI of turbulent kinetic energy. Magn Reson Med 2018; 81:514-523. [PMID: 30265753 DOI: 10.1002/mrm.27397] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 05/04/2018] [Accepted: 05/20/2018] [Indexed: 11/11/2022]
Abstract
PURPOSE To investigate limitations of partial Fourier acquisition in phase-contrast MRI of turbulent kinetic energy (TKE). METHODS To assess the validity of partial Fourier reconstruction of TKE and phase images, computational fluid dynamics data of mean and turbulent velocities in a stenotic U-bend phantom was used. Partial Fourier acquisition with 75% k-space coverage was simulated and TKE data were reconstructed using zero-filling, homodyne reconstruction, and the method of projections onto convex sets (POCS). Results were compared to data from fully sampled k-space and 75% symmetric sampling. In addition, compressed sensing (CS) reconstruction was compared for a standard variable density sampling pattern and a variable density sampling pattern combined with 75% partial Fourier. For illustration purposes, in vivo examples of velocity magnitude and TKE maps of aortic flow reconstructed with the different methods are provided. RESULTS In accordance with theory, partial Fourier reconstruction of TKE maps from phase-contrast data results in artifacts relative to fully sampled data. It is demonstrated that neither homodyne reconstruction nor POCS can improve reconstruction of TKE data with respect to zero-filling reconstruction when compared to ground-truth (RMS error: 4.70%, 4.34%, and 2.45% for homodyne, POCS, and zero-filling reconstruction of in vivo data, respectively). CS reconstruction from data acquired with partial Fourier did not recover the resolution loss incurred by partial Fourier sampling. CONCLUSION Partial Fourier reconstruction of TKE maps from phase-contrast data does not yield a benefit over zero-filling reconstruction. In consequence, symmetric sampling is preferred over partial Fourier acquisition for a given number of phase-encodes in phase-contrast MRI.
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Affiliation(s)
- Jonas Walheim
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Alexander Gotschy
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.,Department of Cardiology, University Hospital Zurich, Zurich, Switzerland
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
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17
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Blood flow patterns and pressure loss in the ascending aorta: A comparative study on physiological and aneurysmal conditions. J Biomech 2018; 76:152-159. [DOI: 10.1016/j.jbiomech.2018.05.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 05/17/2018] [Accepted: 05/30/2018] [Indexed: 01/16/2023]
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18
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Ha H, Ziegler M, Welander M, Bjarnegård N, Carlhäll CJ, Lindenberger M, Länne T, Ebbers T, Dyverfeldt P. Age-Related Vascular Changes Affect Turbulence in Aortic Blood Flow. Front Physiol 2018; 9:36. [PMID: 29422871 PMCID: PMC5788974 DOI: 10.3389/fphys.2018.00036] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 01/10/2018] [Indexed: 02/06/2023] Open
Abstract
Turbulent blood flow is implicated in the pathogenesis of several aortic diseases but the extent and degree of turbulent blood flow in the normal aorta is unknown. We aimed to quantify the extent and degree of turbulece in the normal aorta and to assess whether age impacts the degree of turbulence. 22 young normal males (23.7 ± 3.0 y.o.) and 20 old normal males (70.9 ± 3.5 y.o.) were examined using four dimensional flow magnetic resonance imaging (4D Flow MRI) to quantify the turbulent kinetic energy (TKE), a measure of the intensity of turbulence, in the aorta. All healthy subjects developed turbulent flow in the aorta, with total TKE of 3–19 mJ. The overall degree of turbulence in the entire aorta was similar between the groups, although the old subjects had about 73% more total TKE in the ascending aorta compared to the young subjects (young = 3.7 ± 1.8 mJ, old = 6.4 ± 2.4 mJ, p < 0.001). This increase in ascending aorta TKE in old subjects was associated with age-related dilation of the ascending aorta which increases the volume available for turbulence development. Conversely, age-related dilation of the descending and abdominal aorta decreased the average flow velocity and suppressed the development of turbulence. In conclusion, turbulent blood flow develops in the aorta of normal subjects and is impacted by age-related geometric changes. Non-invasive assessment enables the determination of normal levels of turbulent flow in the aorta which is a prerequisite for understanding the role of turbulence in the pathophysiology of cardiovascular disease.
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Affiliation(s)
- Hojin Ha
- Department of Mechanical and Biomedical Engineering, Kangwon National University, Chuncheon, South Korea.,Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
| | - Magnus Ziegler
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
| | - Martin Welander
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Department of Thoracic and Vascular Surgery, Linköping University, Linköping, Sweden
| | - Niclas Bjarnegård
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Carl-Johan Carlhäll
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden.,Department of Clinical Physiology, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Marcus Lindenberger
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Department of Cardiology, Linköping University, Linköping, Sweden
| | - Toste Länne
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden.,Department of Clinical Physiology, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Tino Ebbers
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
| | - Petter Dyverfeldt
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
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19
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Serial MR, Velasco MI, Silletta EV, Zanotto FM, Dassie SA, Acosta RH. Flow-Pattern Characterization of Biphasic Electrochemical Cells by Magnetic Resonance Imaging under Forced Hydrodynamic Conditions. Chemphyschem 2017; 18:3469-3477. [PMID: 28960697 DOI: 10.1002/cphc.201700775] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Indexed: 11/06/2022]
Abstract
The fluid dynamics of a liquid|liquid system inside a four-electrode electrochemical cell were studied by velocimetry magnetic resonance imaging (MRI) and flow propagator measurements. To characterize this system fully, three different cell configurations operating at two rotational frequencies were analyzed. Quantitative information about the stability of the liquid|liquid interface and the dynamics of the organic phase were determined. The NMR spectroscopy results were in agreement with the electrochemical measurements performed by using the same experimental setup.
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Affiliation(s)
- María R Serial
- FAMAF-Universidad Nacional de Córdoba and IFEG-CONICET, 5000, Ciudad Universitaria, Córdoba, Argentina
| | - Manuel I Velasco
- FAMAF-Universidad Nacional de Córdoba and IFEG-CONICET, 5000, Ciudad Universitaria, Córdoba, Argentina
| | - Emilia V Silletta
- FAMAF-Universidad Nacional de Córdoba and IFEG-CONICET, 5000, Ciudad Universitaria, Córdoba, Argentina
| | - Franco M Zanotto
- Universidad Nacional de Córdoba, Instituto de Investigaciones en Fisicoquímica de córdoba (INFIQC)-CONICET, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, 5000, Ciudad Universitari, Córdoba, Argentina
| | - Sergio A Dassie
- Universidad Nacional de Córdoba, Instituto de Investigaciones en Fisicoquímica de córdoba (INFIQC)-CONICET, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, 5000, Ciudad Universitari, Córdoba, Argentina
| | - Rodolfo H Acosta
- FAMAF-Universidad Nacional de Córdoba and IFEG-CONICET, 5000, Ciudad Universitaria, Córdoba, Argentina
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20
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Gülan U, Saguner A, Akdis D, Gotschy A, Manka R, Brunckhorst C, Holzner M, Duru F. Investigation of Atrial Vortices Using a Novel Right Heart Model and Possible Implications for Atrial Thrombus Formation. Sci Rep 2017; 7:16772. [PMID: 29196688 PMCID: PMC5711865 DOI: 10.1038/s41598-017-17117-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 11/22/2017] [Indexed: 11/15/2022] Open
Abstract
The main aim of this paper is to characterize vortical flow structures in the healthy human right atrium, their impact on wall shear stresses and possible implications for atrial thrombus formation. 3D Particle Tracking Velocimetry is applied to a novel anatomically accurate compliant silicone right heart model to study the phase averaged and fluctuating flow velocity within the right atrium, inferior vena cava and superior vena cava under physiological conditions. We identify the development of two vortex rings in the bulk of the right atrium during the atrial filling phase leading to a rinsing effect at the atrial wall which break down during ventricular filling. We show that the vortex ring formation affects the hemodynamics of the atrial flow by a strong correlation (ρ = 0.7) between the vortical structures and local wall shear stresses. Low wall shear stress regions are associated with absence of the coherent vortical structures which might be potential risk regions for atrial thrombus formation. We discuss possible implications for atrial thrombus formation in different regions of the right atrium.
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Affiliation(s)
- Utku Gülan
- ETH Zurich, Institute of Environmental Engineering, Zurich, 8093, Switzerland.
| | - Ardan Saguner
- University Heart Center, Department of Cardiology, Zurich, 8091, Switzerland
| | - Deniz Akdis
- University Heart Center, Department of Cardiology, Zurich, 8091, Switzerland
| | - Alexander Gotschy
- University Heart Center, Department of Cardiology, Zurich, 8091, Switzerland.,Institute for Biomedical Engineering, University and ETH Zurich, Zurich, 8092, Switzerland
| | - Robert Manka
- University Heart Center, Department of Cardiology, Zurich, 8091, Switzerland
| | - Corinna Brunckhorst
- University Heart Center, Department of Cardiology, Zurich, 8091, Switzerland
| | - Markus Holzner
- ETH Zurich, Institute of Environmental Engineering, Zurich, 8093, Switzerland
| | - Firat Duru
- University Heart Center, Department of Cardiology, Zurich, 8091, Switzerland.,Center for Integrative Human Physiology, University of Zurich, Zurich, 8091, Switzerland
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21
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Giese D, Weiss K, Baeßler B, Madershahian N, Choi YH, Maintz D, Bunck AC. In vitro evaluation of flow patterns and turbulent kinetic energy in trans-catheter aortic valve prostheses. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2017; 31:165-172. [DOI: 10.1007/s10334-017-0651-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 09/04/2017] [Accepted: 09/05/2017] [Indexed: 11/24/2022]
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22
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Binter C, Gotschy A, Sündermann SH, Frank M, Tanner FC, Lüscher TF, Manka R, Kozerke S. Turbulent Kinetic Energy Assessed by Multipoint 4-Dimensional Flow Magnetic Resonance Imaging Provides Additional Information Relative to Echocardiography for the Determination of Aortic Stenosis Severity. Circ Cardiovasc Imaging 2017; 10:CIRCIMAGING.116.005486. [PMID: 28611119 DOI: 10.1161/circimaging.116.005486] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 04/21/2017] [Indexed: 12/25/2022]
Affiliation(s)
- Christian Binter
- From the Institute for Biomedical Engineering, University and ETH Zurich, Switzerland (C.B., A.G., S.K.); Department of Cardiology, University Heart Center (A.G., M.F., F.C.T., T.F.L., R.M.), Division of Internal Medicine (A.G.), and Institute of Diagnostic and Interventional Radiology (R.M.), University Hospital Zurich, Switzerland; Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Germany (S.H.S.); and Imaging Sciences and Biomedical Engineering, King’s College
| | - Alexander Gotschy
- From the Institute for Biomedical Engineering, University and ETH Zurich, Switzerland (C.B., A.G., S.K.); Department of Cardiology, University Heart Center (A.G., M.F., F.C.T., T.F.L., R.M.), Division of Internal Medicine (A.G.), and Institute of Diagnostic and Interventional Radiology (R.M.), University Hospital Zurich, Switzerland; Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Germany (S.H.S.); and Imaging Sciences and Biomedical Engineering, King’s College
| | - Simon H. Sündermann
- From the Institute for Biomedical Engineering, University and ETH Zurich, Switzerland (C.B., A.G., S.K.); Department of Cardiology, University Heart Center (A.G., M.F., F.C.T., T.F.L., R.M.), Division of Internal Medicine (A.G.), and Institute of Diagnostic and Interventional Radiology (R.M.), University Hospital Zurich, Switzerland; Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Germany (S.H.S.); and Imaging Sciences and Biomedical Engineering, King’s College
| | - Michelle Frank
- From the Institute for Biomedical Engineering, University and ETH Zurich, Switzerland (C.B., A.G., S.K.); Department of Cardiology, University Heart Center (A.G., M.F., F.C.T., T.F.L., R.M.), Division of Internal Medicine (A.G.), and Institute of Diagnostic and Interventional Radiology (R.M.), University Hospital Zurich, Switzerland; Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Germany (S.H.S.); and Imaging Sciences and Biomedical Engineering, King’s College
| | - Felix C. Tanner
- From the Institute for Biomedical Engineering, University and ETH Zurich, Switzerland (C.B., A.G., S.K.); Department of Cardiology, University Heart Center (A.G., M.F., F.C.T., T.F.L., R.M.), Division of Internal Medicine (A.G.), and Institute of Diagnostic and Interventional Radiology (R.M.), University Hospital Zurich, Switzerland; Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Germany (S.H.S.); and Imaging Sciences and Biomedical Engineering, King’s College
| | - Thomas F. Lüscher
- From the Institute for Biomedical Engineering, University and ETH Zurich, Switzerland (C.B., A.G., S.K.); Department of Cardiology, University Heart Center (A.G., M.F., F.C.T., T.F.L., R.M.), Division of Internal Medicine (A.G.), and Institute of Diagnostic and Interventional Radiology (R.M.), University Hospital Zurich, Switzerland; Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Germany (S.H.S.); and Imaging Sciences and Biomedical Engineering, King’s College
| | - Robert Manka
- From the Institute for Biomedical Engineering, University and ETH Zurich, Switzerland (C.B., A.G., S.K.); Department of Cardiology, University Heart Center (A.G., M.F., F.C.T., T.F.L., R.M.), Division of Internal Medicine (A.G.), and Institute of Diagnostic and Interventional Radiology (R.M.), University Hospital Zurich, Switzerland; Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Germany (S.H.S.); and Imaging Sciences and Biomedical Engineering, King’s College
| | - Sebastian Kozerke
- From the Institute for Biomedical Engineering, University and ETH Zurich, Switzerland (C.B., A.G., S.K.); Department of Cardiology, University Heart Center (A.G., M.F., F.C.T., T.F.L., R.M.), Division of Internal Medicine (A.G.), and Institute of Diagnostic and Interventional Radiology (R.M.), University Hospital Zurich, Switzerland; Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Germany (S.H.S.); and Imaging Sciences and Biomedical Engineering, King’s College
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23
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Donati F, Myerson S, Bissell MM, Smith NP, Neubauer S, Monaghan MJ, Nordsletten DA, Lamata P. Beyond Bernoulli: Improving the Accuracy and Precision of Noninvasive Estimation of Peak Pressure Drops. Circ Cardiovasc Imaging 2017; 10:CIRCIMAGING.116.005207. [PMID: 28093412 PMCID: PMC5265685 DOI: 10.1161/circimaging.116.005207] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 11/22/2016] [Indexed: 11/16/2022]
Abstract
BACKGROUND Transvalvular peak pressure drops are routinely assessed noninvasively by echocardiography using the Bernoulli principle. However, the Bernoulli principle relies on several approximations that may not be appropriate, including that the majority of the pressure drop is because of the spatial acceleration of the blood flow, and the ejection jet is a single streamline (single peak velocity value). METHODS AND RESULTS We assessed the accuracy of the Bernoulli principle to estimate the peak pressure drop at the aortic valve using 3-dimensional cardiovascular magnetic resonance flow data in 32 subjects. Reference pressure drops were computed from the flow field, accounting for the principles of physics (ie, the Navier-Stokes equations). Analysis of the pressure components confirmed that the spatial acceleration of the blood jet through the valve is most significant (accounting for 99% of the total drop in stenotic subjects). However, the Bernoulli formulation demonstrated a consistent overestimation of the transvalvular pressure (average of 54%, range 5%-136%) resulting from the use of a single peak velocity value, which neglects the velocity distribution across the aortic valve plane. This assumption was a source of uncontrolled variability. CONCLUSIONS The application of the Bernoulli formulation results in a clinically significant overestimation of peak pressure drops because of approximation of blood flow as a single streamline. A corrected formulation that accounts for the cross-sectional profile of the blood flow is proposed and adapted to both cardiovascular magnetic resonance and echocardiographic data.
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Affiliation(s)
- Fabrizio Donati
- From the King's College London, Division of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, The Rayne Institute, United Kingdom (F.D., N.P.S., D.A.N., P.L.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom (S.M., M.M.B., S.N.); University of Auckland, New Zealand (N.P.S.); and Department of Non Invasive Cardiology, King's College Hospital, London, United Kingdom (M.J.M.)
| | - Saul Myerson
- From the King's College London, Division of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, The Rayne Institute, United Kingdom (F.D., N.P.S., D.A.N., P.L.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom (S.M., M.M.B., S.N.); University of Auckland, New Zealand (N.P.S.); and Department of Non Invasive Cardiology, King's College Hospital, London, United Kingdom (M.J.M.)
| | - Malenka M Bissell
- From the King's College London, Division of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, The Rayne Institute, United Kingdom (F.D., N.P.S., D.A.N., P.L.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom (S.M., M.M.B., S.N.); University of Auckland, New Zealand (N.P.S.); and Department of Non Invasive Cardiology, King's College Hospital, London, United Kingdom (M.J.M.)
| | - Nicolas P Smith
- From the King's College London, Division of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, The Rayne Institute, United Kingdom (F.D., N.P.S., D.A.N., P.L.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom (S.M., M.M.B., S.N.); University of Auckland, New Zealand (N.P.S.); and Department of Non Invasive Cardiology, King's College Hospital, London, United Kingdom (M.J.M.)
| | - Stefan Neubauer
- From the King's College London, Division of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, The Rayne Institute, United Kingdom (F.D., N.P.S., D.A.N., P.L.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom (S.M., M.M.B., S.N.); University of Auckland, New Zealand (N.P.S.); and Department of Non Invasive Cardiology, King's College Hospital, London, United Kingdom (M.J.M.)
| | - Mark J Monaghan
- From the King's College London, Division of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, The Rayne Institute, United Kingdom (F.D., N.P.S., D.A.N., P.L.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom (S.M., M.M.B., S.N.); University of Auckland, New Zealand (N.P.S.); and Department of Non Invasive Cardiology, King's College Hospital, London, United Kingdom (M.J.M.)
| | - David A Nordsletten
- From the King's College London, Division of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, The Rayne Institute, United Kingdom (F.D., N.P.S., D.A.N., P.L.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom (S.M., M.M.B., S.N.); University of Auckland, New Zealand (N.P.S.); and Department of Non Invasive Cardiology, King's College Hospital, London, United Kingdom (M.J.M.)
| | - Pablo Lamata
- From the King's College London, Division of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, The Rayne Institute, United Kingdom (F.D., N.P.S., D.A.N., P.L.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom (S.M., M.M.B., S.N.); University of Auckland, New Zealand (N.P.S.); and Department of Non Invasive Cardiology, King's College Hospital, London, United Kingdom (M.J.M.).
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24
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Ha H, Lantz J, Ziegler M, Casas B, Karlsson M, Dyverfeldt P, Ebbers T. Estimating the irreversible pressure drop across a stenosis by quantifying turbulence production using 4D Flow MRI. Sci Rep 2017; 7:46618. [PMID: 28425452 PMCID: PMC5397859 DOI: 10.1038/srep46618] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 03/21/2017] [Indexed: 12/14/2022] Open
Abstract
The pressure drop across a stenotic vessel is an important parameter in medicine, providing a commonly used and intuitive metric for evaluating the severity of the stenosis. However, non-invasive estimation of the pressure drop under pathological conditions has remained difficult. This study demonstrates a novel method to quantify the irreversible pressure drop across a stenosis using 4D Flow MRI by calculating the total turbulence production of the flow. Simulation MRI acquisitions showed that the energy lost to turbulence production can be accurately quantified with 4D Flow MRI within a range of practical spatial resolutions (1-3 mm; regression slope = 0.91, R2 = 0.96). The quantification of the turbulence production was not substantially influenced by the signal-to-noise ratio (SNR), resulting in less than 2% mean bias at SNR > 10. Pressure drop estimation based on turbulence production robustly predicted the irreversible pressure drop, regardless of the stenosis severity and post-stenosis dilatation (regression slope = 0.956, R2 = 0.96). In vitro validation of the technique in a 75% stenosis channel confirmed that pressure drop prediction based on the turbulence production agreed with the measured pressure drop (regression slope = 1.15, R2 = 0.999, Bland-Altman agreement = 0.75 ± 3.93 mmHg).
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Affiliation(s)
- Hojin Ha
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Jonas Lantz
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Magnus Ziegler
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Belen Casas
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Matts Karlsson
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
- Division of Applied Thermodynamics and Fluid Mechanics, Department of Management and Engineering (IEI), Linköping University, Linköping, Sweden
| | - Petter Dyverfeldt
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Tino Ebbers
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
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25
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Ha H, Lantz J, Haraldsson H, Casas B, Ziegler M, Karlsson M, Saloner D, Dyverfeldt P, Ebbers T. Assessment of turbulent viscous stress using ICOSA 4D Flow MRI for prediction of hemodynamic blood damage. Sci Rep 2016; 6:39773. [PMID: 28004789 PMCID: PMC5177919 DOI: 10.1038/srep39773] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/28/2016] [Indexed: 11/20/2022] Open
Abstract
Flow-induced blood damage plays an important role in determining the hemodynamic impact of abnormal blood flow, but quantifying of these effects, which are dominated by shear stresses in highly fluctuating turbulent flow, has not been feasible. This study evaluated the novel application of turbulence tensor measurements using simulated 4D Flow MRI data with six-directional velocity encoding for assessing hemodynamic stresses and corresponding blood damage index (BDI) in stenotic turbulent blood flow. The results showed that 4D Flow MRI underestimates the maximum principal shear stress of laminar viscous stress (PLVS), and overestimates the maximum principal shear stress of Reynolds stress (PRSS) with increasing voxel size. PLVS and PRSS were also overestimated by about 1.2 and 4.6 times at medium signal to noise ratio (SNR) = 20. In contrast, the square sum of the turbulent viscous shear stress (TVSS), which is used for blood damage index (BDI) estimation, was not severely affected by SNR and voxel size. The square sum of TVSS and the BDI at SNR >20 were underestimated by less than 1% and 10%, respectively. In conclusion, this study demonstrated the feasibility of 4D Flow MRI based quantification of TVSS and BDI which are closely linked to blood damage.
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Affiliation(s)
- Hojin Ha
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Jonas Lantz
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Henrik Haraldsson
- University of California, San Francisco, San Francisco, California, United States
| | - Belen Casas
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Magnus Ziegler
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Matts Karlsson
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
- Division of Applied Thermodynamics and Fluid Mechanics, Department of Management and Engineering (IEI), Linköping University, Linköping, Sweden
| | - David Saloner
- University of California, San Francisco, San Francisco, California, United States
| | - Petter Dyverfeldt
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Tino Ebbers
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
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26
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von Knobelsdorff-Brenkenhoff F, Karunaharamoorthy A, Trauzeddel RF, Barker AJ, Blaszczyk E, Markl M, Schulz-Menger J. Evaluation of Aortic Blood Flow and Wall Shear Stress in Aortic Stenosis and Its Association With Left Ventricular Remodeling. Circ Cardiovasc Imaging 2016; 9:e004038. [PMID: 26917824 DOI: 10.1161/circimaging.115.004038] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Aortic stenosis (AS) leads to variable stress for the left ventricle (LV) and consequently a broad range of LV remodeling. The aim of this study was to describe blood flow patterns in the ascending aorta of patients with AS and determine their association with remodeling. METHODS AND RESULTS Thirty-seven patients with AS (14 mild, 8 moderate, 15 severe; age, 63±13 years) and 37 healthy controls (age, 60±10 years) underwent 4-dimensional-flow magnetic resonance imaging. Helical and vortical flow formations and flow eccentricity were assessed in the ascending aorta. Normalized flow displacement from the vessel center and peak systolic wall shear stress in the ascending aorta were quantified. LV remodeling was assessed based on LV mass index and the ratio of LV mass:end-diastolic volume (relative wall mass). Marked helical and vortical flow formation and eccentricity were more prevalent in patients with AS than in healthy subjects, and patients with AS exhibited an asymmetrical and elevated distribution of peak systolic wall shear stress. In AS, aortic orifice area was strongly negatively associated with vortical flow formation (P=0.0274), eccentricity (P=0.0070), and flow displacement (P=0.0021). Bicuspid aortic valve was associated with more intense helical (P=0.0098) and vortical flow formation (P=0.0536), higher flow displacement (P=0.11), and higher peak systolic wall shear stress (P=0.0926). LV mass index and relative wall mass were significantly associated with aortic orifice area (P=0.0611, P=0.0058) and flow displacement (P=0.0058, P=0.0283). CONCLUSIONS In this pilot study, AS leads to abnormal blood flow pattern and peak systolic wall shear stress in the ascending aorta. In addition to aortic orifice area, normalized flow displacement was significantly associated with LV remodeling.
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Affiliation(s)
- Florian von Knobelsdorff-Brenkenhoff
- From the Working Group Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a Joint Cooperation Between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany (F.v.K.-B., A.K., R.F.T., E.B., J.S.-M.); Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL (A.J.B., M.M.); and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (M.M.).
| | - Achudhan Karunaharamoorthy
- From the Working Group Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a Joint Cooperation Between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany (F.v.K.-B., A.K., R.F.T., E.B., J.S.-M.); Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL (A.J.B., M.M.); and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (M.M.)
| | - Ralf Felix Trauzeddel
- From the Working Group Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a Joint Cooperation Between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany (F.v.K.-B., A.K., R.F.T., E.B., J.S.-M.); Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL (A.J.B., M.M.); and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (M.M.)
| | - Alex J Barker
- From the Working Group Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a Joint Cooperation Between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany (F.v.K.-B., A.K., R.F.T., E.B., J.S.-M.); Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL (A.J.B., M.M.); and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (M.M.)
| | - Edyta Blaszczyk
- From the Working Group Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a Joint Cooperation Between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany (F.v.K.-B., A.K., R.F.T., E.B., J.S.-M.); Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL (A.J.B., M.M.); and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (M.M.)
| | - Michael Markl
- From the Working Group Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a Joint Cooperation Between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany (F.v.K.-B., A.K., R.F.T., E.B., J.S.-M.); Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL (A.J.B., M.M.); and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (M.M.)
| | - Jeanette Schulz-Menger
- From the Working Group Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a Joint Cooperation Between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany (F.v.K.-B., A.K., R.F.T., E.B., J.S.-M.); Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL (A.J.B., M.M.); and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (M.M.)
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