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Williamson PN, Docherty PD, Jermy M, Steven BM. Literature Survey for In-Vivo Reynolds and Womersley Numbers of Various Arteries and Implications for Compliant In-Vitro Modelling. Cardiovasc Eng Technol 2024; 15:418-430. [PMID: 38499933 PMCID: PMC11319390 DOI: 10.1007/s13239-024-00723-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 02/19/2024] [Indexed: 03/20/2024]
Abstract
PURPOSE In-vitro modelling can be used to investigate haemodynamics of arterial geometry and stent implants. However, in-vitro model fidelity relies on precise matching of in-vivo conditions. In pulsatile flow, velocity distribution and wall shear stress depend on compliance, and the Reynolds and Womersley numbers. However, matching such values may lead to unachievable tolerances in phantom fabrication. METHODS Published Reynolds and Womersley numbers for 14 major arteries in the human body were determined via a literature search. Preference was given to in-vivo publications but in-vitro and in-silico values were presented when in-vivo values were not found. Subsequently ascending aorta and carotid artery case studies were presented to highlight the limitations dynamic matching would apply to phantom fabrication. RESULTS Seven studies reported the in-vivo Reynolds and Womersley numbers for the aorta and two for the carotid artery. However, only one study each reported in-vivo numbers for the remaining ten arteries. No in-vivo data could be found for the femoral, superior mesenteric and renal arteries. Thus, information derived in-vitro and in-silico were provided instead. The ascending aorta and carotid artery models required scaling to 1.5× and 3× life-scale, respectively, to achieve dimensional tolerance restrictions. Modelling the ascending aorta with the comparatively high viscosity water/glycerine solution will lead to high pump power demands. However, all the working fluids considered could be dynamically matched with low pump demand for the carotid model. CONCLUSION This paper compiles available human haemodynamic information, and highlights the paucity of information for some arteries. It also provides a method for optimal in-vitro experimental configuration.
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Affiliation(s)
- P N Williamson
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
| | - P D Docherty
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand.
- Institute of Technical Medicine, Furtwangen University, Campus Villingen-Schwenningen, Jakob-Kienzle Strasse 17, 78054, Villingen-Schwenningen, Germany.
| | - M Jermy
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
| | - B M Steven
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
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Rotundu A, Nedelcu AH, Tepordei RT, Moraru MC, Chiran DA, Oancea A, Maștaleru A, Costache AD, Chirica C, Grosu C, Mitu F, Leon MM. Medical-Surgical Implications of Branching Variation of Human Aortic Arch Known as Bovine Aortic Arch (BAA). J Pers Med 2024; 14:678. [PMID: 39063932 PMCID: PMC11278178 DOI: 10.3390/jpm14070678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Revised: 06/16/2024] [Accepted: 06/21/2024] [Indexed: 07/28/2024] Open
Abstract
(1) Background: The aortic arch (AA) branching model is challenging, considering the multiple anatomical variations documented in existing research. The bovine aortic arch (BAA) is the most prevalent anatomical variation among these. This variant of AA branching has long been considered a nonsymptomatic malformation, having been discovered incidentally during imaging investigations for other causes. However, more recent studies have demonstrated that BAA shows a frequent association with coarctation of the aorta (CoA), thoracic aortic disease (TAD), and stroke. At the same time, given the current context of increasing activity in the fields of interventional and surgical procedures in the aorta and its branches, it is very important to know the medical-surgical implications of this anatomical variant. (2) Methods: We conducted a comprehensive review using PubMed and Embase, focusing specifically on randomized trials and cohort analyses that examined the medical-surgical implications of BAA. We assessed information related to studied groups, medical procedures, and study outcomes. Initially, we identified 8454 studies, and after rigorous evaluation, we narrowed down our review to 25 articles. (3) Discussions: The intervention consisted of assessing the risks associated with BAA through different imaging investigation methods such as computer tomographic angiography (CTA), magnetic resonance imaging (MRI), or ultrasonography (US). The following results were evaluated: the prevalence of the BAA, the importance of imaging investigations in establishing the diagnosis and the therapeutic management and monitoring the evolution of patients with the BAA, the association of the BAA with CoA, TAD, and stroke, and the potential risks of interventional treatment in patients with the BAA. (4) Conclusions: The prevalence of the BAA differs both between different ethnic groups and between genders. Advanced imaging methods such as CTA and 4D flow MRI allow detailed descriptions of supra-aortic vascular anatomy and information about blood flow velocities, direction, and turbulence in the AA. US remains an easy and valuable imaging investigation, with the potential to detect and correctly diagnose the BAA and its hemodynamic implications. Anatomical variations in the AA are associated with increased rates of TAD, CoA, and stroke, necessitating early diagnosis and increased supervision of patients with such incidentally observed abnormalities. In addition, there is a need to further develop and refine the surgical techniques used and personalize them to the individual characteristics of patients with the BAA.
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Affiliation(s)
- Andreea Rotundu
- Doctoral School, “Grigore T. Popa” University of Medicine and Pharmacy, 16 Universității Street, 700115 Iasi, Romania; (A.R.); (C.C.)
- Department of Medical Specialties I, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (A.O.); (A.M.); (A.-D.C.); (F.M.); (M.M.L.)
| | - Alin Horatiu Nedelcu
- Department of Morpho-Functional Science I, Discipline of Anatomy, “Grigore T. Popa” University of Medicine and Pharmacy, 16 Universitatii Street, 700115 Iasi, Romania; (R.T.T.); (M.C.M.); (D.A.C.)
- Radiology Clinic, Clinical Rehabilitation Hospital, 700661 Iasi, Romania
| | - Razvan Tudor Tepordei
- Department of Morpho-Functional Science I, Discipline of Anatomy, “Grigore T. Popa” University of Medicine and Pharmacy, 16 Universitatii Street, 700115 Iasi, Romania; (R.T.T.); (M.C.M.); (D.A.C.)
| | - Marius Constantin Moraru
- Department of Morpho-Functional Science I, Discipline of Anatomy, “Grigore T. Popa” University of Medicine and Pharmacy, 16 Universitatii Street, 700115 Iasi, Romania; (R.T.T.); (M.C.M.); (D.A.C.)
| | - Dragos Andrei Chiran
- Department of Morpho-Functional Science I, Discipline of Anatomy, “Grigore T. Popa” University of Medicine and Pharmacy, 16 Universitatii Street, 700115 Iasi, Romania; (R.T.T.); (M.C.M.); (D.A.C.)
| | - Andra Oancea
- Department of Medical Specialties I, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (A.O.); (A.M.); (A.-D.C.); (F.M.); (M.M.L.)
- Clinical Rehabilitation Hospital, 700661 Iasi, Romania
| | - Alexandra Maștaleru
- Department of Medical Specialties I, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (A.O.); (A.M.); (A.-D.C.); (F.M.); (M.M.L.)
- Clinical Rehabilitation Hospital, 700661 Iasi, Romania
| | - Alexandru-Dan Costache
- Department of Medical Specialties I, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (A.O.); (A.M.); (A.-D.C.); (F.M.); (M.M.L.)
- Clinical Rehabilitation Hospital, 700661 Iasi, Romania
| | - Costin Chirica
- Doctoral School, “Grigore T. Popa” University of Medicine and Pharmacy, 16 Universității Street, 700115 Iasi, Romania; (A.R.); (C.C.)
| | - Cristina Grosu
- Department of Neurology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
- Department of Neurology, Rehabilitation Hospital, 700661 Iasi, Romania
| | - Florin Mitu
- Department of Medical Specialties I, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (A.O.); (A.M.); (A.-D.C.); (F.M.); (M.M.L.)
- Clinical Rehabilitation Hospital, 700661 Iasi, Romania
| | - Maria Magdalena Leon
- Department of Medical Specialties I, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (A.O.); (A.M.); (A.-D.C.); (F.M.); (M.M.L.)
- Clinical Rehabilitation Hospital, 700661 Iasi, Romania
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Catalano C, Crascì F, Puleo S, Scuoppo R, Pasta S, Raffa GM. Computational fluid dynamics in cardiac surgery and perfusion: A review. Perfusion 2024:2676591241239277. [PMID: 38850015 DOI: 10.1177/02676591241239277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2024]
Abstract
Cardiovascular diseases persist as a leading cause of mortality and morbidity, despite significant advances in diagnostic and surgical approaches. Computational Fluid Dynamics (CFD) represents a branch of fluid mechanics widely used in industrial engineering but is increasingly applied to the cardiovascular system. This review delves into the transformative potential for simulating cardiac surgery procedures and perfusion systems, providing an in-depth examination of the state-of-the-art in cardiovascular CFD modeling. The study first describes the rationale for CFD modeling and later focuses on the latest advances in heart valve surgery, transcatheter heart valve replacement, aortic aneurysms, and extracorporeal membrane oxygenation. The review underscores the role of CFD in better understanding physiopathology and its clinical relevance, as well as the profound impact of hemodynamic stimuli on patient outcomes. By integrating computational methods with advanced imaging techniques, CFD establishes a quantitative framework for understanding the intricacies of the cardiac field, providing valuable insights into disease progression and treatment strategies. As technology advances, the evolving synergy between computational simulations and clinical interventions is poised to revolutionize cardiovascular care. This collaboration sets the stage for more personalized and effective therapeutic strategies. With its potential to enhance our understanding of cardiac pathologies, CFD stands as a promising tool for improving patient outcomes in the dynamic landscape of cardiovascular medicine.
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Affiliation(s)
- Chiara Catalano
- Department of Engineering, Università degli Studi di Palermo, Palermo, Italy
| | - Fabrizio Crascì
- Department of Engineering, Università degli Studi di Palermo, Palermo, Italy
- Department of Research, IRCCS-ISMETT, Palermo, Italy
| | - Silvia Puleo
- Department of Engineering, Università degli Studi di Palermo, Palermo, Italy
| | - Roberta Scuoppo
- Department of Engineering, Università degli Studi di Palermo, Palermo, Italy
| | - Salvatore Pasta
- Department of Engineering, Università degli Studi di Palermo, Palermo, Italy
- Department of Research, IRCCS-ISMETT, Palermo, Italy
| | - Giuseppe M Raffa
- Department for the Treatment and Study of Cardiothoracic Diseases and Cardiothoracic Transplantation, IRCCS-ISMETT, Palermo, Italy
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Takei Y, Miyazaki S, Suzuki K, Saito S, Oogaki H, Muraoka Y, Ogasawara T, Tezuka M, Shibasaki I, Fukuda H. Hemodynamic predictors of negative false lumen remodeling after frozen elephant trunk for acute aortic dissection. Gen Thorac Cardiovasc Surg 2024; 72:376-386. [PMID: 37948001 PMCID: PMC11127806 DOI: 10.1007/s11748-023-01984-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 10/18/2023] [Indexed: 11/12/2023]
Abstract
OBJECTIVE We evaluated the blood flow within the downstream aortic false lumen after frozen elephant trunk repair for acute aortic dissection and identified hemodynamic predictors of false lumen expansion and negative false lumen remodeling using four-dimensional flow magnetic resonance imaging. METHODS Thirty-one patients (Stanford type A, n = 28; Stanford type B, n = 3) with patent false lumen who underwent frozen elephant trunk procedures for acute aortic dissection were included in this observational study. Each patient underwent computed tomography during the follow-up period and four-dimensional flow magnetic resonance imaging within 3 postoperative months. The false lumen volumetric expansion rate was calculated using computed tomography data. The direction and the rate of flow in the lower descending aortic false lumen were analyzed. Negative false lumen remodeling was defined as a volumetric increase of > 10% from the baseline volume. RESULTS Negative false lumen remodeling had developed in 6 of the 31 patients during the observation period. Most of the false lumen flows were biphasic during systole. The range between peak and nadir flow rates was associated with the false lumen volumetric expansion rate (β coefficient = 6.77; p < 0.01, R2 = 0.43). CONCLUSIONS The range between peak and nadir flow rates may serve as a hemodynamic predictor of negative false lumen remodeling, enabling further treatment for patients at risk of expansion in the downstream aorta.
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Affiliation(s)
- Yusuke Takei
- Department of Cardiac and Vascular Surgery, Dokkyo Medical University Graduate School of Medicine, 880 Kitakobayashi, Mibu-machi, Shimotuga-gun, Tochigi, 321-0293, Japan.
| | | | | | | | - Hayato Oogaki
- Department of Radiology, Dokkyo Medical University Hospital, Mibu-machi, Tochigi, Japan
| | - Yuki Muraoka
- Department of Radiology, Dokkyo Medical University Hospital, Mibu-machi, Tochigi, Japan
| | - Takeshi Ogasawara
- Mathematics and Statistics Section, Department of Fundamental Education, Dokkyo Medical University, Mibu-machi, Tochigi, Japan
| | - Masahiro Tezuka
- Department of Cardiac and Vascular Surgery, Dokkyo Medical University Graduate School of Medicine, 880 Kitakobayashi, Mibu-machi, Shimotuga-gun, Tochigi, 321-0293, Japan
| | - Ikuko Shibasaki
- Department of Cardiac and Vascular Surgery, Dokkyo Medical University Graduate School of Medicine, 880 Kitakobayashi, Mibu-machi, Shimotuga-gun, Tochigi, 321-0293, Japan
| | - Hirotsugu Fukuda
- Department of Cardiac and Vascular Surgery, Dokkyo Medical University Graduate School of Medicine, 880 Kitakobayashi, Mibu-machi, Shimotuga-gun, Tochigi, 321-0293, Japan
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Koike H, Nishimura T, Morikawa M. Quantitative evaluation of pulmonary hypertension using 4D flow MRI: A retrospective study. Heliyon 2024; 10:e31177. [PMID: 38813238 PMCID: PMC11133668 DOI: 10.1016/j.heliyon.2024.e31177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/01/2024] [Accepted: 05/12/2024] [Indexed: 05/31/2024] Open
Abstract
Background Pulmonary hypertension (PH) is a severe vascular disorder that may affect 50 % of patients with heart failure. Currently, right-sided heart catheterization is required to definitively diagnose PH. However, this method is invasive and thus may not be appropriate for repeated, long-term monitoring of PH patients. This retrospective study's aim was to evaluate whether 4D flow magnetic resonance imaging (MRI) can be used to quantitively measure flow parameters to identify patients with PH. Methods The study cohort included 97 patients recruited from a single institution and divided into three groups based on echocardiographic estimate of pulmonary artery systolic pressure (PASP): normal group with PASP<36 mmHg, borderline PH group with PASP of 37-50 mmHg, and PH group with PASP>50 mmHg. 4D flow MRI was used to quantitively assess blood flow and velocity, regurgitation, wall shear stress (WSS) and kinetic energy in the pulmonary artery trunk, right main pulmonary artery, and left pulmonary artery. Two experienced radiologists independently analyzed the MR images, blinded to clinical details. Results We found a significant difference in WSS in the pulmonary artery trunk, right main pulmonary artery and left main pulmonary artery among the three patient groups. We also found significant differences in the kinetic energy and average through velocity in the pulmonary artery trunk and right main pulmonary artery, and significant differences in the flow rate in the right main pulmonary artery. Conclusion These data suggest that 4D flow MRI can quantitate pulmonary artery flow parameters and distinguish between patients with and without PH.
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Affiliation(s)
- Hirofumi Koike
- Department of Radiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan
| | - Takamasa Nishimura
- Department of Radiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan
| | - Minoru Morikawa
- Department of Radiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan
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Aslan S, Liu X, Wu Q, Mass P, Loke YH, Johnson J, Huddle J, Olivieri L, Hibino N, Krieger A. Virtual Planning and Patient-Specific Graft Design for Aortic Repairs. Cardiovasc Eng Technol 2024; 15:123-136. [PMID: 37985613 DOI: 10.1007/s13239-023-00701-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 11/07/2023] [Indexed: 11/22/2023]
Abstract
PURPOSE Patients presenting with coarctation of the aorta (CoA) may also suffer from co-existing transverse arch hypoplasia (TAH). Depending on the risks associated with the surgery and the severity of TAH, clinicians may decide to repair only CoA, and monitor the TAH to see if it improves as the patient grows. While acutely successful, eventually hemodynamics may become suboptimal if TAH is left untreated. The objective of this work aims to develop a patient-specific surgical planning framework for predicting and assessing postoperative outcomes of simple CoA repair and comprehensive repair of CoA and TAH. METHODS The surgical planning framework consisted of virtual clamp placement, stenosis resection, and design and optimization of patient-specific aortic grafts that involved geometrical modeling of the graft and computational fluid dynamics (CFD) simulation for evaluating various surgical plans. Time-dependent CFD simulations were performed using Windkessel boundary conditions at the outlets that were obtained from patient-specific non-invasive pressure and flow data to predict hemodynamics before and after the virtual repairs. We applied the proposed framework to investigate optimal repairs for six patients (n = 6) diagnosed with both CoA and TAH. Design optimization was performed by creating a combination of a tubular graft and a waterslide patch to reconstruct the aortic arch. The surfaces of the designed graft were parameterized to optimize the shape. RESULTS Peak systolic pressure drop (PSPD) and time-averaged wall shear stress (TAWSS) were used as performance metrics to evaluate surgical outcomes of various graft designs and implantation. The average PSPD improvements were 28% and 44% after the isolated CoA repair and comprehensive repair, respectively. Maximum values of TAWSS were decreased by 60% after CoA repair and further improved by 22% after the comprehensive repair. The oscillatory shear index was calculated and the values were confirmed to be in the normal range after the repairs. CONCLUSION The results showed that the comprehensive repair outperforms the simple CoA repair and may be more advantageous in the long term in some patients. We demonstrated that the surgical planning and patient-specific flow simulations could potentially affect the selection and outcomes of aorta repairs.
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Affiliation(s)
- Seda Aslan
- Department of Mechanical Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD, 21218, USA.
| | - Xiaolong Liu
- Department of Mechanical Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD, 21218, USA
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, USA
| | - Qiyuan Wu
- Department of Mechanical Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD, 21218, USA
| | - Paige Mass
- Division of Cardiology, Children's National Hospital, Washington, DC, USA
| | - Yue-Hin Loke
- Division of Cardiology, Children's National Hospital, Washington, DC, USA
| | | | | | - Laura Olivieri
- Division of Cardiology, Children's National Hospital, Washington, DC, USA
| | - Narutoshi Hibino
- Section of Cardiac Surgery, Department of Surgery, The University of Chicago Medicine, Chicago, IL, USA
| | - Axel Krieger
- Department of Mechanical Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD, 21218, USA
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Ali AM, Ghobashy AA, Sultan AA, Elkhodary KI, El-Morsi M. A 3D scaling law for supravalvular aortic stenosis suited for stethoscopic auscultations. Heliyon 2024; 10:e26190. [PMID: 38390109 PMCID: PMC10881376 DOI: 10.1016/j.heliyon.2024.e26190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 11/24/2023] [Accepted: 02/08/2024] [Indexed: 02/24/2024] Open
Abstract
In this study a frequency scaling law for 3D anatomically representative supravalvular aortic stenosis (SVAS) cases is proposed. The law is uncovered for stethoscopy's preferred auscultation range (70-120 Hz). LES simulations are performed on the CFD solver Fluent, leveraging Simulia's Living Heart Human Model (LHHM), modified to feature hourglass stenoses that range between 30 to 80 percent (mild to severe) in addition to the descending aorta. For physiological hemodynamic boundary conditions the Windkessel model is implemented via a UDF subroutine. The flow-generated acoustic signal is then extracted using the FW-H model and analyzed using FFT. A preferred receiver location that matches clinical practice is confirmed (right intercostal space) and a correlation between the degree of stenosis and a corresponding acoustic frequency is obtained. Five clinical auscultation signals are tested against the scaling law, with the findings interpreted in relation to the NHS classification of stenosis and to the assessments of experienced cardiologists. The scaling law is thus shown to succeed as a potential quantitative decision-support tool for clinicians, enabling them to reliably interpret stethoscopic auscultations for all degrees of stenosis, which is especially useful for moderate degrees of SVAS. Computational investigation of more complex stenotic cases would enhance the clinical relevance of this proposed scaling law, and will be explored in future research.
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Affiliation(s)
- Ahmed M Ali
- Department of Mechanical Engineering, The American University in Cairo, 11835 New Cairo, Egypt
| | - Aly A Ghobashy
- Department of Mechanical Engineering, The American University in Cairo, 11835 New Cairo, Egypt
| | - Abdelrahman A Sultan
- Department of Mechanical Engineering, The American University in Cairo, 11835 New Cairo, Egypt
| | - Khalil I Elkhodary
- Department of Mechanical Engineering, The American University in Cairo, 11835 New Cairo, Egypt
| | - Mohamed El-Morsi
- Department of Mechanical Engineering, The American University in Cairo, 11835 New Cairo, Egypt
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Takahashi Y, Kamiya K, Nagai T, Tsuneta S, Oyama-Manabe N, Hamaya T, Kazui S, Yasui Y, Saiin K, Naito S, Mizuguchi Y, Takenaka S, Tada A, Ishizaka S, Kobayashi Y, Omote K, Sato T, Shingu Y, Kudo K, Wakasa S, Anzai T. Differences in blood flow dynamics between balloon- and self-expandable valves in patients with aortic stenosis undergoing transcatheter aortic valve replacement. J Cardiovasc Magn Reson 2023; 25:60. [PMID: 37880721 PMCID: PMC10601149 DOI: 10.1186/s12968-023-00970-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 09/26/2023] [Indexed: 10/27/2023] Open
Abstract
BACKGROUND The differences in pre- and early post-procedural blood flow dynamics between the two major types of bioprosthetic valves, the balloon-expandable valve (BEV) and self-expandable valve (SEV), in patients with aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR), have not been investigated. We aimed to investigate the differences in blood flow dynamics between the BEV and SEV using four-dimensional flow cardiovascular magnetic resonance (4D flow CMR). METHODS We prospectively examined 98 consecutive patients with severe AS who underwent TAVR between May 2018 and November 2021 (58 BEV and 40 SEV) after excluding those without CMR because of a contraindication, inadequate imaging from the analyses, or patients' refusal. CMR was performed in all participants before (median interval, 22 [interquartile range (IQR) 4-39] days) and after (median interval, 6 [IQR 3-6] days) TAVR. We compared the changes in blood flow patterns, wall shear stress (WSS), and energy loss (EL) in the ascending aorta (AAo) between the BEV and SEV using 4D flow CMR. RESULTS The absolute reductions in helical flow and flow eccentricity were significantly higher in the SEV group compared in the BEV group after TAVR (BEV: - 0.22 ± 0.86 vs. SEV: - 0.85 ± 0.80, P < 0.001 and BEV: - 0.11 ± 0.79 vs. SEV: - 0.50 ± 0.88, P = 0.037, respectively); there were no significant differences in vortical flow between the groups. The absolute reduction of average WSS was significantly higher in the SEV group compared to the BEV group after TAVR (BEV: - 0.6 [- 2.1 to 0.5] Pa vs. SEV: - 1.8 [- 3.5 to - 0.8] Pa, P = 0.006). The systolic EL in the AAo significantly decreased after TAVR in both the groups, while the absolute reduction was comparable between the groups. CONCLUSIONS Helical flow, flow eccentricity, and average WSS in the AAo were significantly decreased after SEV implantation compared to BEV implantation, providing functional insights for valve selection in patients with AS undergoing TAVR. Our findings offer valuable insights into blood flow dynamics, aiding in the selection of valves for patients with AS undergoing TAVR. Further larger-scale studies are warranted to confirm the prognostic significance of hemodynamic changes in these patients.
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Affiliation(s)
- Yuki Takahashi
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Kiwamu Kamiya
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Toshiyuki Nagai
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan.
| | - Satonori Tsuneta
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Kita 14, Nishi 5, Kita-Ku, Sapporo, Hokkaido, 060-8648, Japan
| | - Noriko Oyama-Manabe
- Department of Radiology, Jichi Medical University Saitama Medical Center, 1-847 Amanuma-Cho, Omiya-Ku, Saitama-City, Saitama, 330-8503, Japan
| | - Takeshi Hamaya
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Sho Kazui
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Yutaro Yasui
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Kohei Saiin
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Seiichiro Naito
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Yoshifumi Mizuguchi
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Sakae Takenaka
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Atsushi Tada
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Suguru Ishizaka
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Yuta Kobayashi
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Kazunori Omote
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Takuma Sato
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Yasushige Shingu
- Department of Cardiovascular Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Kohsuke Kudo
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Kita 14, Nishi 5, Kita-Ku, Sapporo, Hokkaido, 060-8648, Japan
| | - Satoru Wakasa
- Department of Cardiovascular Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Toshihisa Anzai
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
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9
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Ali AM, Hafez AH, Elkhodary KI, El-Morsi M. A CFD-FFT approach to hemoacoustics that enables degree of stenosis prediction from stethoscopic signals. Heliyon 2023; 9:e17643. [PMID: 37449099 PMCID: PMC10336451 DOI: 10.1016/j.heliyon.2023.e17643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 06/20/2023] [Accepted: 06/23/2023] [Indexed: 07/18/2023] Open
Abstract
In this paper, we identify a new (acoustic) frequency-stenosis relation whose frequencies lie within the recommended auscultation threshold of stethoscopy (< 120 Hz). We show that this relation can be used to extend the application of phonoangiography (quantifying the degree of stenosis from bruits) to widely accessible stethoscopes. The relation is successfully identified from an analysis restricted to the acoustic signature of the von Karman vortex street, which we automatically single out by means of a metric we propose that is based on an area-weighted average of the Q-criterion for the post-stenotic region. Specifically, we perform CFD simulations on internal flow geometries that represent stenotic blood vessels of different severities. We then extract their emitted acoustic signals using the Ffowcs Williams-Hawkings equation, which we subtract from a clean signal (stenosis free) at the same heart rate. Next, we transform this differential signal to the frequency domain and carefully classify its acoustic signatures per six (stenosis-)invariant flow phases of a cardiac cycle that are newly identified in this paper. We then automatically restrict our acoustic analysis to the sounds emitted by the von Karman vortex street (phase 4) by means of our Q-criterion-based metric. Our analysis of its acoustic signature reveals a strong linear relationship between the degree of stenosis and its dominant frequency, which differs considerably from the break frequency and the heart rate (known dominant frequencies in the literature). Applying our new relation to available stethoscopic data, we find that its predictions are consistent with clinical assessment. Our finding of this linear correlation is also unlike prevalent scaling laws in the literature, which feature a small exponent (i.e., low stenosis percentage sensitivity over much of the clinical range). They hence can only distinguish mild, moderate, and severe cases. Conversely, our linear law can identify variations in the degree of stenosis sensitively and accurately for the full clinical range, thus significantly improving the utility of the relevant scaling laws... Future research will investigate incorporating the vibroacoustic role of adjacent organs to expand the clinical applicability of our findings. Extending our approach to more complex 3D stenotic morphologies and including the vibroacoustic role of surrounding organs will be explored in future research to advance the clinical reach of our findings.
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Affiliation(s)
- Ahmed M. Ali
- Department of Mechanical Engineering, The American University in Cairo, 11835 New Cairo, Egypt
| | - Ahmed H. Hafez
- Department of Mechanical Engineering, The American University in Cairo, 11835 New Cairo, Egypt
- Aerospace Engineering Department, Cairo University, 12511 Giza, Egypt
| | - Khalil I. Elkhodary
- Department of Mechanical Engineering, The American University in Cairo, 11835 New Cairo, Egypt
| | - Mohamed El-Morsi
- Department of Mechanical Engineering, The American University in Cairo, 11835 New Cairo, Egypt
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10
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Tsubata H, Nakanishi N, Itatani K, Takigami M, Matsubara Y, Ogo T, Fukuda T, Matsuda H, Matoba S. Pulmonary artery blood flow dynamics in chronic thromboembolic pulmonary hypertension. Sci Rep 2023; 13:6490. [PMID: 37081116 PMCID: PMC10119089 DOI: 10.1038/s41598-023-33727-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/18/2023] [Indexed: 04/22/2023] Open
Abstract
Chronic thromboembolic pulmonary hypertension is caused by incomplete resolution and organization of thrombi. Blood flow dynamics are involved in thrombus formation; however, only a few studies have reported on pulmonary artery blood flow dynamics in patients with chronic thromboembolic pulmonary hypertension. Furthermore, the effects of treatment interventions on pulmonary artery blood flow dynamics are not fully understood. The aim of the study was to evaluate pulmonary artery blood flow dynamics in patients with chronic thromboembolic pulmonary hypertension before and after pulmonary endarterectomy and balloon pulmonary angioplasty, using computational fluid dynamics. We analyzed patient-specific pulmonary artery models of 10 patients with chronic thromboembolic pulmonary hypertension and three controls using computational fluid dynamics. In patients with chronic thromboembolic pulmonary hypertension, flow velocity and wall shear stress in the pulmonary arteries were significantly decreased, and the oscillatory shear index and blood stagnation volume were significantly increased than in controls. Pulmonary endarterectomy induced redistribution of pulmonary blood flow and improved blood flow dynamics in the pulmonary artery. Balloon pulmonary angioplasty improved pulmonary blood flow disturbance, decreased blood flow stagnation, and increased wall shear stress, leading to vasodilatation of the distal portion of the pulmonary artery following balloon pulmonary angioplasty treatment.
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Affiliation(s)
- Hideo Tsubata
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajii-cho Kawaramachi-Hirokoji, Kamigyo-ward, Kyoto, 602-8566, Japan
| | - Naohiko Nakanishi
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajii-cho Kawaramachi-Hirokoji, Kamigyo-ward, Kyoto, 602-8566, Japan.
| | - Keiichi Itatani
- Department of Cardiovascular Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Masao Takigami
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajii-cho Kawaramachi-Hirokoji, Kamigyo-ward, Kyoto, 602-8566, Japan
| | - Yuki Matsubara
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajii-cho Kawaramachi-Hirokoji, Kamigyo-ward, Kyoto, 602-8566, Japan
| | - Takeshi Ogo
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Tetsuya Fukuda
- Department of Radiology, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Hitoshi Matsuda
- Department of Vascular Surgery, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Satoaki Matoba
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajii-cho Kawaramachi-Hirokoji, Kamigyo-ward, Kyoto, 602-8566, Japan
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11
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Jonnagiri R, Sundström E, Gutmark E, Anderson S, Pednekar AS, Taylor MD, Tretter JT, Gutmark-Little I. Influence of aortic valve morphology on vortical structures and wall shear stress. Med Biol Eng Comput 2023; 61:1489-1506. [PMID: 36763231 DOI: 10.1007/s11517-023-02790-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 01/19/2023] [Indexed: 02/11/2023]
Abstract
The aim of this paper is to assess the association between valve morphology and vortical structures quantitatively and to highlight the influence of valve morphology/orientation on aorta's susceptibility to shear stress, both proximal and distal. Four-dimensional phase-contrast magnetic resonance imaging (4D PCMRI) data of 6 subjects, 3 with tricuspid aortic valve (TAV) and 3 with functionally bicuspid aortic values (BAV) with right-left coronary leaflet fusion, were processed and analyzed for vorticity and wall shear stress trends. Computational fluid dynamics (CFD) has been used with moving TAV and BAV valve designs in patient-specific aortae to compare with in vivo shear stress data. Vorticity from 4D PCMRI data about the aortic centerline demonstrated that TAVs had a higher number of vortical flow structures than BAVs at peak systole. Coalescing of flow structures was shown to be possible in the arch region of all subjects. Wall shear stress (WSS) distribution from CFD results at the aortic root is predominantly symmetric for TAVs but highly asymmetric for BAVs with the region opposite the raphe (fusion location of underdeveloped leaflets) being subjected to higher WSS. Asymmetry in the size and number of leaflets in BAVs and TAVs significantly influence vortical structures and WSS in the proximal aorta for all valve types and distal aorta for certain valve orientations of BAV. Analysis of vortical structures using 4D PCMRI data (on the left side) and wall shear stress data using CFD (on the right side).
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Affiliation(s)
- Raghuvir Jonnagiri
- Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, OH, 45221, USA.
| | - Elias Sundström
- Department of Engineering Mechanics, Royal Institute of Technology, 10044, Stockholm, Sweden
| | - Ephraim Gutmark
- Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, OH, 45221, USA
| | - Shae Anderson
- Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Amol S Pednekar
- Division of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Michael D Taylor
- Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA.,Department of Pediatrics, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Justin T Tretter
- Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA.,Department of Pediatrics, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Iris Gutmark-Little
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, 45267, USA.,Division of Endocrinology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
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12
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Bhardwaj S, Craven BA, Sever JE, Costanzo F, Simon SD, Manning KB. Modeling Flow in an In Vitro Anatomical Cerebrovascular Model with Experimental Validation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.13.523948. [PMID: 36711518 PMCID: PMC9882108 DOI: 10.1101/2023.01.13.523948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Acute ischemic stroke (AIS) is a leading cause of mortality that occurs when an embolus becomes lodged in the cerebral vasculature and obstructs blood flow in the brain. The severity of AIS is determined by the location and how extensively emboli become lodged, which are dictated in large part by the cerebral flow and the dynamics of embolus migration which are difficult to measure in vivo in AIS patients. Computational fluid dynamics (CFD) can be used to predict the patient-specific hemodynamics and embolus migration and lodging in the cerebral vasculature to better understand the underlying mechanics of AIS. To be relied upon, however, the computational simulations must be verified and validated. In this study, a realistic in vitro experimental model and a corresponding computational model of the cerebral vasculature are established that can be used to investigate flow and embolus migration and lodging in the brain. First, the in vitro anatomical model is described, including how the flow distribution in the model is tuned to match physiological measurements from the literature. Measurements of pressure and flow rate for both normal and stroke conditions were acquired and corresponding CFD simulations were performed and compared with the experiments to validate the flow predictions. Overall, the CFD simulations were in relatively close agreement with the experiments, to within ±7% of the mean experimental data with many of the CFD predictions within the uncertainty of the experimental measurement. This work provides an in vitro benchmark data set for flow in a realistic cerebrovascular model and is a first step towards validating a computational model of AIS.
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Affiliation(s)
- Saurabh Bhardwaj
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Brent A. Craven
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Jacob E. Sever
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Francesco Costanzo
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, USA
| | - Scott D. Simon
- Department of Neurosurgery, Penn State Hershey Medical Center, Hershey, PA, USA
| | - Keefe B. Manning
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
- Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, USA
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13
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Bhardwaj S, Craven BA, Sever JE, Costanzo F, Simon SD, Manning KB. Modeling flow in an in vitro anatomical cerebrovascular model with experimental validation. FRONTIERS IN MEDICAL TECHNOLOGY 2023; 5:1130201. [PMID: 36908295 PMCID: PMC9996037 DOI: 10.3389/fmedt.2023.1130201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/09/2023] [Indexed: 02/25/2023] Open
Abstract
Acute ischemic stroke (AIS) is a leading cause of mortality that occurs when an embolus becomes lodged in the cerebral vasculature and obstructs blood flow in the brain. The severity of AIS is determined by the location and how extensively emboli become lodged, which are dictated in large part by the cerebral flow and the dynamics of embolus migration which are difficult to measure in vivo in AIS patients. Computational fluid dynamics (CFD) can be used to predict the patient-specific hemodynamics and embolus migration and lodging in the cerebral vasculature to better understand the underlying mechanics of AIS. To be relied upon, however, the computational simulations must be verified and validated. In this study, a realistic in vitro experimental model and a corresponding computational model of the cerebral vasculature are established that can be used to investigate flow and embolus migration and lodging in the brain. First, the in vitro anatomical model is described, including how the flow distribution in the model is tuned to match physiological measurements from the literature. Measurements of pressure and flow rate for both normal and stroke conditions were acquired and corresponding CFD simulations were performed and compared with the experiments to validate the flow predictions. Overall, the CFD simulations were in relatively close agreement with the experiments, to within ±7% of the mean experimental data with many of the CFD predictions within the uncertainty of the experimental measurement. This work provides an in vitro benchmark data set for flow in a realistic cerebrovascular model and is a first step towards validating a computational model of AIS.
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Affiliation(s)
- Saurabh Bhardwaj
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, United States
| | - Brent A. Craven
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States
- Correspondence: Brent A. Craven Keefe B. Manning
| | - Jacob E. Sever
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, United States
| | - Francesco Costanzo
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, United States
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, United States
| | - Scott D. Simon
- Department of Neurosurgery, Penn State Hershey Medical Center, Hershey, PA, United States
| | - Keefe B. Manning
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, United States
- Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, United States
- Correspondence: Brent A. Craven Keefe B. Manning
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14
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Garreau M, Puiseux T, Toupin S, Giese D, Mendez S, Nicoud F, Moreno R. Accelerated sequences of 4D flow MRI using GRAPPA and compressed sensing: A comparison against conventional MRI and computational fluid dynamics. Magn Reson Med 2022; 88:2432-2446. [PMID: 36005271 DOI: 10.1002/mrm.29404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/30/2022] [Accepted: 07/14/2022] [Indexed: 01/07/2023]
Abstract
PURPOSE To evaluate hemodynamic markers obtained by accelerated GRAPPA (R = 2, 3, 4) and compressed sensing (R = 7.6) 4D flow MRI sequences under complex flow conditions. METHODS The accelerated 4D flow MRI scans were performed on a pulsatile flow phantom, along with a nonaccelerated fully sampled k-space acquisition. Computational fluid dynamics simulations based on the experimentally measured flow fields were conducted for additional comparison. Voxel-wise comparisons (Bland-Altman analysis, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:msub><mml:mi>L</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:mrow> <mml:annotation>$$ {L}_2 $$</mml:annotation></mml:semantics> </mml:math> -norm metric), as well as nonderived quantities (velocity profiles, flow rates, and peak velocities), were used to compare the velocity fields obtained from the different modalities. RESULTS 4D flow acquisitions and computational fluid dynamics depicted similar hemodynamic patterns. Voxel-wise comparisons between the MRI scans highlighted larger discrepancies at the voxels located near the phantom's boundary walls. A trend for all MR scans to overestimate velocity profiles and peak velocities as compared to computational fluid dynamics was noticed in regions associated with high velocity or acceleration. However, good agreement for the flow rates was observed, and eddy-current correction appeared essential for consistency of the flow rates measurements with respect to the principle of mass conservation. CONCLUSION GRAPPA (R = 2, 3) and highly accelerated compressed sensing showed good agreement with the fully sampled acquisition. Yet, all 4D flow MRI scans were hampered by artifacts inherent to the phase-contrast acquisition procedure. Computational fluid dynamics simulations are an interesting tool to assess these differences but are sensitive to modeling parameters.
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Affiliation(s)
- Morgane Garreau
- University of Montpellier, CNRS, Montpellier, France.,Spin Up, ALARA Group, Strasbourg, France
| | - Thomas Puiseux
- Spin Up, ALARA Group, Strasbourg, France.,I2MC, INSERM/UPS UMR 1297, Toulouse, France
| | | | - Daniel Giese
- Magnetic Resonance, Siemens Healthcare GmbH, Erlangen, Germany
| | - Simon Mendez
- University of Montpellier, CNRS, Montpellier, France
| | - Franck Nicoud
- University of Montpellier, CNRS, Montpellier, France
| | - Ramiro Moreno
- I2MC, INSERM/UPS UMR 1297, Toulouse, France.,ALARA Expertise, ALARA Group, Strasbourg, France
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15
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Park J, Kim J, Hyun S, Lee J. Hemodynamics in a three-dimensional printed aortic model: a comparison of four-dimensional phase-contrast magnetic resonance and image-based computational fluid dynamics. MAGMA (NEW YORK, N.Y.) 2022; 35:719-732. [PMID: 35133539 DOI: 10.1007/s10334-021-00984-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 12/03/2021] [Accepted: 12/03/2021] [Indexed: 06/14/2023]
Abstract
OBJECTIVE This study aims to compare an electrocardiogram (ECG)-gated four-dimensional (4D) phase-contrast (PC) magnetic resonance imaging (MRI) technique and computational fluid dynamics (CFD) using variables controlled in a laboratory environment to minimize bias factors. MATERIALS AND METHODS Data from 4D PC-MRI were compared with computational fluid dynamics using steady and pulsatile flows at various inlet velocities. Anatomically realistic models for a normal aorta, a penetrating atherosclerotic ulcer, and an abdominal aortic aneurysm were constructed using a three-dimensional printer. RESULTS For the normal aorta model, the errors in the peak and the average velocities were within 5%. The peak velocities of the penetrating atherosclerotic ulcer and the abdominal aortic aneurysm models displayed a more extensive range of differences because of the high-speed and vortical fluid flows generated by the shape of the blood vessel. However, the average velocities revealed only relatively minor differences. CONCLUSIONS This study compared the characteristics of PC-MRI and CFD through a phantom study that only included controllable experimental parameters. Based on these results, 4D PC-MRI and CFD are powerful tools for analyzing blood flow patterns in vivo. However, there is room for future developments to improve velocity measurement accuracy.
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Affiliation(s)
- Jieun Park
- Nonlinear Dynamics Research Center, Kyungpook National University, Daegu, Republic of Korea
| | - Junghun Kim
- Bio-Medical Research Institute, Kyungpook National University and Hospital, Daegu, Korea.
| | - Sinjae Hyun
- Department of Biomedical Engineering, Mercer University, Macon, GA, 31207, USA
| | - Jongmin Lee
- Department of Radiology, Kyungpook National University and Hospital, 50, Sam-Duk 2 Ga, Jung Gu, Daegu, 700-721, Republic of Korea.
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16
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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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17
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Cherry M, Khatir Z, Khan A, Bissell M. The impact of 4D-Flow MRI spatial resolution on patient-specific CFD simulations of the thoracic aorta. Sci Rep 2022; 12:15128. [PMID: 36068322 PMCID: PMC9448751 DOI: 10.1038/s41598-022-19347-6] [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: 06/22/2022] [Accepted: 08/29/2022] [Indexed: 11/29/2022] Open
Abstract
Magnetic Resonance Imaging (MRI) is considered the gold standard of medical imaging technologies as it allows for accurate imaging of blood vessels. 4-Dimensional Flow Magnetic Resonance Imaging (4D-Flow MRI) is built on conventional MRI, and provides flow data in the three vector directions and a time resolved magnitude data set. As such it can be used to retrospectively calculate haemodynamic parameters of interest, such as Wall Shear Stress (WSS). However, multiple studies have indicated that a significant limitation of the imaging technique is the spatiotemporal resolution that is currently available. Recent advances have proposed and successfully integrated 4D-Flow MRI imaging techniques with Computational Fluid Dynamics (CFD) to produce patient-specific simulations that have the potential to aid in treatments,surgical decision making, and risk stratification. However, the consequences of using insufficient 4D-Flow MRI spatial resolutions on any patient-specific CFD simulations is currently unclear, despite being a recognised limitation. The research presented in this study aims to quantify the inaccuracies in patient-specific 4D-Flow MRI based CFD simulations that can be attributed to insufficient spatial resolutions when acquiring 4D-Flow MRI data. For this research, a patient has undergone four 4D-Flow MRI scans acquired at various isotropic spatial resolutions and patient-specific CFD simulations have subsequently been run using geometry and velocity data produced from each scan. It was found that compared to CFD simulations based on a \documentclass[12pt]{minimal}
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\begin{document}$$1.5\,{\text {mm}} \times 1.5\,{\text {mm}} \times 1.5\,{\text {mm}}$$\end{document}1.5mm×1.5mm×1.5mm, using a spatial resolution of \documentclass[12pt]{minimal}
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\begin{document}$$4\,{\text {mm}} \times 4\,{\text {mm}} \times 4\,{\text {mm}}$$\end{document}4mm×4mm×4mm substantially underestimated the maximum velocity magnitude at peak systole by \documentclass[12pt]{minimal}
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\begin{document}$$110.55\%$$\end{document}110.55%. The impacts of 4D-Flow MRI spatial resolution on WSS calculated from CFD simulations have been investigated and it has been shown that WSS is underestimated in CFD simulations that are based on a coarse 4D-Flow MRI spatial resolution. The authors have concluded that a minimum 4D-Flow MRI spatial resolution of \documentclass[12pt]{minimal}
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\begin{document}$$1.5\,{\text {mm}} \times 1.5\,{\text {mm}} \times 1.5\,{\text {mm}}$$\end{document}1.5mm×1.5mm×1.5mm must be used when acquiring 4D-Flow MRI data to perform patient-specific CFD simulations. A coarser spatial resolution will produce substantial differences within the flow field and geometry.
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Affiliation(s)
- Molly Cherry
- CDT in Fluid Dynamics, School of Computing, University of Leeds, Leeds, LS2 9JT, UK.
| | - Zinedine Khatir
- School of Engineering and the Built Environment, Birmingham City University, Birmingham, B4 7XG, UK.,School of Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, UK
| | - Amirul Khan
- School of Civil Engineering, University of Leeds, Leeds, LS2 9JT, UK
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18
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Ling Y, Schenkel T, Tang J, Liu H. Computational fluid dynamics investigation on aortic hemodynamics in double aortic arch before and after ligation surgery. J Biomech 2022; 141:111231. [PMID: 35901663 DOI: 10.1016/j.jbiomech.2022.111231] [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: 02/24/2022] [Revised: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 02/08/2023]
Abstract
Double aortic arch (DAA) malformation is one of the reasons for symptomatic vascular rings, the hemodynamics of which is still poorly understood. This study aims to investigate the blood flow characteristics in patient-specific double aortic arches using computational fluid dynamics (CFD). Seven cases of infantile patients with DAA were collected and their computed tomography images were used to reconstruct 3D computational models. A modified Carreau model was used to consider the non-Newtonian effect of blood and a three-element Windkessel model taking the effect of the age of patients into account was applied to reproduce physiological pressure waveforms. Numerical results show that blood flow distribution and energy loss of DAA depends on relative sizes of the two aortic arches and their angles with the ascending aorta. Ligation of either aortic arch increases the energy loss of blood in the DAA, leading to the increase in cardiac workload. Generally, the rising rate of energy loss before and after the surgery is almost linear with the area ratio between the aortic arch without ligation and the ascending aorta.
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Affiliation(s)
- Yunfei Ling
- Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu 610041, China; State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource & Hydropower, Sichuan University, Chengdu 610065, China
| | - Torsten Schenkel
- Department of Engineering and Mathematics, Sheffield Hallam University, Sheffield S1 1WB, United Kingdom
| | - Jiguo Tang
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource & Hydropower, Sichuan University, Chengdu 610065, China.
| | - Hongtao Liu
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource & Hydropower, Sichuan University, Chengdu 610065, China
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19
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Shahid L, Rice J, Berhane H, Rigsby C, Robinson J, Griffin L, Markl M, Roldán-Alzate A. Enhanced 4D Flow MRI-Based CFD with Adaptive Mesh Refinement for Flow Dynamics Assessment in Coarctation of the Aorta. Ann Biomed Eng 2022; 50:1001-1016. [PMID: 35624334 PMCID: PMC11034844 DOI: 10.1007/s10439-022-02980-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 05/11/2022] [Indexed: 01/28/2023]
Abstract
4D Flow MRI is a diagnostic tool that can visualize and quantify patient-specific hemodynamics and help interventionalists optimize treatment strategies for repairing coarctation of the aorta (COA). Despite recent developments in 4D Flow MRI, shortcomings include phase-offset errors, limited spatiotemporal resolution, aliasing, inaccuracies due to slow aneurysmal flows, and distortion of images due to metallic artifact from vascular stents. To address these limitations, we developed a framework utilizing Computational Fluid Dynamics (CFD) with Adaptive Mesh Refinement (AMR) that enhances 4D Flow MRI visualization/quantification. We applied this framework to five pediatric patients with COA, providing in-vivo and in-silico datasets, pre- and post-intervention. These two data sets were compared and showed that CFD flow rates were within 9.6% of 4D Flow MRI, which is within a clinically acceptable range. CFD simulated slow aneurysmal flow, which MRI failed to capture due to high relative velocity encoding (Venc). CFD successfully predicted in-stent blood flow, which was not visible in the in-vivo data due to susceptibility artifact. AMR improved spatial resolution by factors of 101 to 103 and temporal resolution four-fold. This computational framework has strong potential to optimize visualization/quantification of aneurysmal and in-stent flows, improve spatiotemporal resolution, and assess hemodynamic efficiency post-COA treatment.
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Affiliation(s)
- Labib Shahid
- Department of Mechanical Engineering, University of Wisconsin-Madison, 1111 Highland Ave, Room 2476 WIMR II, Madison, WI, 53705, USA.
| | - James Rice
- Department of Mechanical Engineering, University of Wisconsin-Madison, 1111 Highland Ave, Room 2476 WIMR II, Madison, WI, 53705, USA
| | - Haben Berhane
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, USA
| | - Cynthia Rigsby
- Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Joshua Robinson
- Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Lindsay Griffin
- Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Michael Markl
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, USA
| | - Alejandro Roldán-Alzate
- Department of Mechanical Engineering, University of Wisconsin-Madison, 1111 Highland Ave, Room 2476 WIMR II, Madison, WI, 53705, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Department of Radiology, University of Wisconsin-Madison, Madison, WI, USA
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20
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Takei Y, Shibasaki I, Suzuki K, Miyazaki S, Hirota S, Ohashi H, Saito S, Fukuda H. Hemolytic anemia caused by an excessively kinked prosthetic graft after total arch replacement detected by 4-dimensional flow magnetic resonance imaging: A case report. Medicine (Baltimore) 2022; 101:e29617. [PMID: 35866824 PMCID: PMC9302348 DOI: 10.1097/md.0000000000029617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
RATIONALE Hemolytic anemia is a rare postoperative complication of aortic surgery, which may be caused by an excessively kinked graft that causes abnormal blood flow. It has been reported that 4-dimensional flow magnetic resonance imaging (4D flow MRI) can identify abnormal flow. Herein, we report the guidance of 4D flow MRI in performing the revision procedure for a patient with hemolytic anemia by evaluating abnormal blood flow based on this method. PATIENT CONCERNS A 70-year-old woman presented with dizziness and fatigue. She had undergone total arch replacement with a frozen elephant trunk 5 years prior. We diagnosed hemolytic anemia caused by a kinked graft after total arch replacement. DIAGNOSIS Although computed tomography findings revealed 3 lesions of the kinked graft at the ascending portion and cervical branches, 4D flow MRI findings showed that only the kinked graft at the ascending portion caused hemolytic anemia due to an elevated viscous energy loss around it. INTERVENTION We performed surgery to remove the kinked section instead of revision surgery consisting of total arch replacement. OUTCOMES The patient's postoperative course was uneventful and there were no complications. Postoperative enhanced computed tomography findings showed that the repaired graft had an adequate length and smoothly curved shape. The 4D flow MRI findings revealed smooth flow in the ascending portion and decreased viscous energy loss. LESSONS Based on the 4D flow MRI findings, we adopted a less invasive approach, repairing only the ascending portion of the graft, instead of performing revision surgery comprising total arch replacement.
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Affiliation(s)
- Yusuke Takei
- Department of Cardiac and Vascular Surgery, Dokkyo Medical University Hospital, Mibu-Machi, Tochigi, Japan
- *Correspondence: Yusuke Takei, Department of Cardiac and Vascular Surgery, Dokkyo Medical University, 880 Kitakobayashi, Mibu-machi, Shimotuga-gun, Tochigi 321-0293, Japan (e-mail: )
| | - Ikuko Shibasaki
- Department of Cardiac and Vascular Surgery, Dokkyo Medical University Hospital, Mibu-Machi, Tochigi, Japan
| | | | | | - Shotaro Hirota
- Department of Cardiac and Vascular Surgery, Dokkyo Medical University Hospital, Mibu-Machi, Tochigi, Japan
| | - Hirotaka Ohashi
- Department of Cardiac and Vascular Surgery, Dokkyo Medical University Hospital, Mibu-Machi, Tochigi, Japan
| | - Shunsuke Saito
- Department of Cardiac and Vascular Surgery, Dokkyo Medical University Hospital, Mibu-Machi, Tochigi, Japan
| | - Hirotsugu Fukuda
- Department of Cardiac and Vascular Surgery, Dokkyo Medical University Hospital, Mibu-Machi, Tochigi, Japan
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21
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Kamada H, Nakamura M, Ota H, Higuchi S, Takase K. Blood flow analysis with computational fluid dynamics and 4D-flow MRI for vascular diseases. J Cardiol 2022; 80:386-396. [PMID: 35718672 DOI: 10.1016/j.jjcc.2022.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 05/16/2022] [Indexed: 10/31/2022]
Abstract
Both computational fluid dynamics (CFD) and time-resolved, three-dimensional, phase-contrast, magnetic resonance imaging (4D-flow MRI) enable visualization of time-varying blood flow structures and quantification of blood flow in vascular diseases. However, they are totally different. CFD is a method to calculate blood flow by solving the governing equations of fluid mechanics, so the obtained flow field is somewhat virtual. On the other hand, 4D-flow MRI measures blood flow in vivo, thus the flow is real. Recently, with the development and enhancement of computers, medical imaging techniques, and related software, blood flow analysis has become more accessible to clinicians and its usefulness in vascular diseases has been demonstrated. In this review, we have outlined the methods and characteristics of CFD and 4D-flow MRI, respectively. We have discussed the differences in the characteristics between both methods; reviewed the milestones achieved by blood flow analysis in various vascular diseases; and discussed the usefulness, challenges, and limitations of blood flow analysis. We have discussed the difficulties and limitations of current blood flow analysis. We have also discussed our views on future directions.
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Affiliation(s)
- Hiroki Kamada
- Department of Diagnostic Radiology, Tohoku University Hospital, Sendai, Japan.
| | - Masanori Nakamura
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya, Japan
| | - Hideki Ota
- Department of Diagnostic Radiology, Tohoku University Hospital, Sendai, Japan
| | - Satoshi Higuchi
- Department of Diagnostic Radiology, Tohoku University Hospital, Sendai, Japan
| | - Kei Takase
- Department of Diagnostic Radiology, Tohoku University Hospital, Sendai, Japan
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22
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Sadeghi R, Tomka B, Khodaei S, Daeian M, Gandhi K, Garcia J, Keshavarz-Motamed Z. Impact of extra-anatomical bypass on coarctation fluid dynamics using patient-specific lumped parameter and Lattice Boltzmann modeling. Sci Rep 2022; 12:9718. [PMID: 35690596 PMCID: PMC9188592 DOI: 10.1038/s41598-022-12894-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 04/11/2022] [Indexed: 01/28/2023] Open
Abstract
Accurate hemodynamic analysis is not only crucial for successful diagnosis of coarctation of the aorta (COA), but intervention decisions also rely on the hemodynamics assessment in both pre and post intervention states to minimize patient risks. Despite ongoing advances in surgical techniques for COA treatments, the impacts of extra-anatomic bypass grafting, a surgical technique to treat COA, on the aorta are not always benign. Our objective was to investigate the impact of bypass grafting on aortic hemodynamics. We investigated the impact of bypass grafting on aortic hemodynamics using a patient-specific computational-mechanics framework in three patients with COA who underwent bypass grafting. Our results describe that bypass grafting improved some hemodynamic metrics while worsened the others: (1) Doppler pressure gradient improved (decreased) in all patients; (2) Bypass graft did not reduce the flow rate substantially through the COA; (3) Systemic arterial compliance increased in patients #1 and 3 and didn't change (improve) in patient 3; (4) Hypertension got worse in all patients; (5) The flow velocity magnitude improved (reduced) in patient 2 and 3 but did not improve significantly in patient 1; (6) There were elevated velocity magnitude, persistence of vortical flow structure, elevated turbulence characteristics, and elevated wall shear stress at the bypass graft junctions in all patients. We concluded that bypass graft may lead to pseudoaneurysm formation and potential aortic rupture as well as intimal hyperplasia due to the persistent abnormal and irregular aortic hemodynamics in some patients. Moreover, post-intervention, exposures of endothelial cells to high shear stress may lead to arterial remodeling, aneurysm, and rupture.
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Affiliation(s)
- Reza Sadeghi
- grid.25073.330000 0004 1936 8227Department of Mechanical Engineering, McMaster University, Hamilton, Canada ON
| | - Benjamin Tomka
- grid.25073.330000 0004 1936 8227Department of Mechanical Engineering, McMaster University, Hamilton, Canada ON
| | - Seyedvahid Khodaei
- grid.25073.330000 0004 1936 8227Department of Mechanical Engineering, McMaster University, Hamilton, Canada ON
| | - MohammadAli Daeian
- grid.25073.330000 0004 1936 8227Department of Mechanical Engineering, McMaster University, Hamilton, Canada ON
| | - Krishna Gandhi
- grid.25073.330000 0004 1936 8227Department of Mechanical Engineering, McMaster University, Hamilton, Canada ON
| | - Julio Garcia
- grid.489011.50000 0004 0407 3514Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute of Alberta, Calgary, AB Canada ,grid.22072.350000 0004 1936 7697Department of Radiology, University of Calgary, Calgary, AB Canada ,grid.22072.350000 0004 1936 7697Department of Cardiac Sciences, University of Calgary, Calgary, AB Canada ,grid.413571.50000 0001 0684 7358Alberta Children’s Hospital Research Institute, Calgary, AB Canada
| | - Zahra Keshavarz-Motamed
- grid.25073.330000 0004 1936 8227Department of Mechanical Engineering, McMaster University, Hamilton, Canada ON ,grid.25073.330000 0004 1936 8227School of Biomedical Engineering, McMaster University, Hamilton, ON Canada ,grid.25073.330000 0004 1936 8227School of Computational Science and Engineering, McMaster University, Hamilton, ON Canada
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23
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Qiao Y, Luo K, Fan J. Component quantification of aortic blood flow energy loss using computational fluid-structure interaction hemodynamics. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 221:106826. [PMID: 35526507 DOI: 10.1016/j.cmpb.2022.106826] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 04/13/2022] [Accepted: 04/19/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND OBJECTIVES The aorta serves as the main tube of the human blood circulation system. Energy loss (EL) occurs when blood flows through the aorta and there may be a potential correlation between EL and aortic diseases. However, the components of blood flow EL are still not fully understood. This study aims to quantitatively reveal the EL components in healthy and diseased aortas. METHODS We construct an idealized healthy aorta and three idealized representative diseased aortas: aortic aneurysm, coarctation of the aorta, and aortic dissection. Computational hemodynamic studies are carried out by using the fluid-structure interaction simulation framework. RESULTS Four kinds of EL components: viscous friction, turbulence dissipation, wall deformation, and local lesion are firstly acquired in healthy and diseased aortas based on the high-resolution blood flow information. Viscous friction contributes most to the EL (45.69%-57.22%). EL caused by the deformation of the aortic wall ranks second (15.18%-33.12%). The proportions of turbulence dissipation and local lesion depend on individual geometric characteristics. Besides, the buffering efficiency of the healthy and diseased aorta is about 80%. CONCLUSIONS This study quantitatively reports the components of blood flow EL in healthy and diseased aortas, the finding may provide novel insights into the pathogenesis of aortic diseases.
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Affiliation(s)
- Yonghui Qiao
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China
| | - Kun Luo
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China; Shanghai Institute for Advanced Study of Zhejiang University, Shanghai, China.
| | - Jianren Fan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China; Shanghai Institute for Advanced Study of Zhejiang University, Shanghai, China
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24
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He Y, Northrup H, Le H, Cheung AK, Berceli SA, Shiu YT. Medical Image-Based Computational Fluid Dynamics and Fluid-Structure Interaction Analysis in Vascular Diseases. Front Bioeng Biotechnol 2022; 10:855791. [PMID: 35573253 PMCID: PMC9091352 DOI: 10.3389/fbioe.2022.855791] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 04/08/2022] [Indexed: 01/17/2023] Open
Abstract
Hemodynamic factors, induced by pulsatile blood flow, play a crucial role in vascular health and diseases, such as the initiation and progression of atherosclerosis. Computational fluid dynamics, finite element analysis, and fluid-structure interaction simulations have been widely used to quantify detailed hemodynamic forces based on vascular images commonly obtained from computed tomography angiography, magnetic resonance imaging, ultrasound, and optical coherence tomography. In this review, we focus on methods for obtaining accurate hemodynamic factors that regulate the structure and function of vascular endothelial and smooth muscle cells. We describe the multiple steps and recent advances in a typical patient-specific simulation pipeline, including medical imaging, image processing, spatial discretization to generate computational mesh, setting up boundary conditions and solver parameters, visualization and extraction of hemodynamic factors, and statistical analysis. These steps have not been standardized and thus have unavoidable uncertainties that should be thoroughly evaluated. We also discuss the recent development of combining patient-specific models with machine-learning methods to obtain hemodynamic factors faster and cheaper than conventional methods. These critical advances widen the use of biomechanical simulation tools in the research and potential personalized care of vascular diseases.
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Affiliation(s)
- Yong He
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, FL, United States
| | - Hannah Northrup
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
| | - Ha Le
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
| | - Alfred K. Cheung
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
- Veterans Affairs Salt Lake City Healthcare System, Salt Lake City, UT, United States
| | - Scott A. Berceli
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, FL, United States
- Vascular Surgery Section, Malcom Randall Veterans Affairs Medical Center, Gainesville, FL, United States
| | - Yan Tin Shiu
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
- Veterans Affairs Salt Lake City Healthcare System, Salt Lake City, UT, United States
- *Correspondence: Yan Tin Shiu,
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25
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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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26
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Sugiyama M, Takehara Y, Naganawa S. Does the Pulsatile Non-uniform Flow Matter in MR Flowmetry? Magn Reson Med Sci 2022; 21:365-371. [PMID: 35173117 DOI: 10.2463/mrms.rev.2021-0099] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
3D cine phase-contrast (4D flow) MRI is a sequence with great potential for non-invasive time-resolved 3D flowmetry at arbitrary vessel sections in various blood vessels. However, it is not widely known that the flowmetry with 4D flow MRI is vulnerable to pulsatile and non-uniform flow. Due to the limited spatial and temporal resolutions, averaging within the 3D voxel is occurring during the flowmetry. A simple solution is to avoid setting the measurement plane in the area where non-uniform flow is dominant, which is possible with an aid of streamline depictions generated by computational fluid dynamics (CFD) or 4D flow MRI data. Unlike 4D flow MRI, flowmetry in CFD simulation can use higher spatial and temporal resolution depending on computer performance; therefore, it is robust to fluctuating non-uniform flow. However, the performance of CFD simulations might be limited due to inlet conditions with low temporal resolution. Difficulty applying complex blood flow such as reflection flow from periphery may also limit accurate simulation. Caution should be taken when comparing the result of CFD simulation to that of 4D flow measurement.
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Affiliation(s)
- Masataka Sugiyama
- Departments of Fundamental Development for Advanced Low Invasive Diagnostic Imaging, Nagoya University, Graduate School of Medicine.,Departments of Radiology, Nagoya University, Graduate School of Medicine
| | - Yasuo Takehara
- Departments of Fundamental Development for Advanced Low Invasive Diagnostic Imaging, Nagoya University, Graduate School of Medicine.,Departments of Radiology, Nagoya University, Graduate School of Medicine
| | - Shinji Naganawa
- Departments of Radiology, Nagoya University, Graduate School of Medicine
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27
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Ferdian E, Dubowitz DJ, Mauger CA, Wang A, Young AA. WSSNet: Aortic Wall Shear Stress Estimation Using Deep Learning on 4D Flow MRI. Front Cardiovasc Med 2022; 8:769927. [PMID: 35141290 PMCID: PMC8818720 DOI: 10.3389/fcvm.2021.769927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/30/2021] [Indexed: 11/13/2022] Open
Abstract
Wall shear stress (WSS) is an important contributor to vessel wall remodeling and atherosclerosis. However, image-based WSS estimation from 4D Flow MRI underestimates true WSS values, and the accuracy is dependent on spatial resolution, which is limited in 4D Flow MRI. To address this, we present a deep learning algorithm (WSSNet) to estimate WSS trained on aortic computational fluid dynamics (CFD) simulations. The 3D CFD velocity and coordinate point clouds were resampled into a 2D template of 48 × 93 points at two inward distances (randomly varied from 0.3 to 2.0 mm) from the vessel surface (“velocity sheets”). The algorithm was trained on 37 patient-specific geometries and velocity sheets. Results from 6 validation and test cases showed high accuracy against CFD WSS (mean absolute error 0.55 ± 0.60 Pa, relative error 4.34 ± 4.14%, 0.92 ± 0.05 Pearson correlation) and noisy synthetic 4D Flow MRI at 2.4 mm resolution (mean absolute error 0.99 ± 0.91 Pa, relative error 7.13 ± 6.27%, and 0.79 ± 0.10 Pearson correlation). Furthermore, the method was applied on in vivo 4D Flow MRI cases, effectively estimating WSS from standard clinical images. Compared with the existing parabolic fitting method, WSSNet estimates showed 2–3 × higher values, closer to CFD, and a Pearson correlation of 0.68 ± 0.12. This approach, considering both geometric and velocity information from the image, is capable of estimating spatiotemporal WSS with varying image resolution, and is more accurate than existing methods while still preserving the correct WSS pattern distribution.
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Affiliation(s)
- Edward Ferdian
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
- *Correspondence: Edward Ferdian
| | - David J. Dubowitz
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Charlene A. Mauger
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Alan Wang
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Alistair A. Young
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
- Department of Biomedical Engineering, King's College London, London, United Kingdom
- Alistair A. Young
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28
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Celi S, Vignali E, Capellini K, Gasparotti E. On the Role and Effects of Uncertainties in Cardiovascular in silico Analyses. FRONTIERS IN MEDICAL TECHNOLOGY 2022; 3:748908. [PMID: 35047960 PMCID: PMC8757785 DOI: 10.3389/fmedt.2021.748908] [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] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 10/14/2021] [Indexed: 12/13/2022] Open
Abstract
The assessment of cardiovascular hemodynamics with computational techniques is establishing its fundamental contribution within the world of modern clinics. Great research interest was focused on the aortic vessel. The study of aortic flow, pressure, and stresses is at the basis of the understanding of complex pathologies such as aneurysms. Nevertheless, the computational approaches are still affected by sources of errors and uncertainties. These phenomena occur at different levels of the computational analysis, and they also strongly depend on the type of approach adopted. With the current study, the effect of error sources was characterized for an aortic case. In particular, the geometry of a patient-specific aorta structure was segmented at different phases of a cardiac cycle to be adopted in a computational analysis. Different levels of surface smoothing were imposed to define their influence on the numerical results. After this, three different simulation methods were imposed on the same geometry: a rigid wall computational fluid dynamics (CFD), a moving-wall CFD based on radial basis functions (RBF) CFD, and a fluid-structure interaction (FSI) simulation. The differences of the implemented methods were defined in terms of wall shear stress (WSS) analysis. In particular, for all the cases reported, the systolic WSS and the time-averaged WSS (TAWSS) were defined.
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Affiliation(s)
- Simona Celi
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy
| | - Emanuele Vignali
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy
| | - Katia Capellini
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy.,Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Emanuele Gasparotti
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy.,Department of Information Engineering, University of Pisa, Pisa, Italy
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29
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Chen Z, Zhao H, Zhao Y, Han J, Yang X, Throckmorton A, Wei Z, Ge S, He Y. Retrograde flow in aortic isthmus in normal and fetal heart disease by principal component analysis and computational fluid dynamics. Echocardiography 2022; 39:166-177. [PMID: 35026051 DOI: 10.1111/echo.15256] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 10/04/2021] [Accepted: 10/28/2021] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVES Reverse flow Retrograde flow (RF) of blood in the aortic isthmus can be observed in different types of fetal heart disease (FHD), including abnormalities in heart structure and function. This study sought to investigate the relationship between RF and blood flow parameters, and develop a computational fluid dynamics (CFD) model to understand the mechanisms underlying this observation. MATERIAL AND METHODS A total of 281 fetuses (gestational age [GA] 26.6±.3 weeks) with FHD and 2803 normal fetuses (GA: 26.1±.1 weeks) by fetal echocardiography collected from May 2016 to December 2018. Principal component analysis (PCA) was performed to find the relationship and the CFD model reconstructed from 3D/4D spatio-temporal image correlation (STIC) images to simulate hemodynamics. RESULTS There was a significant difference in the percentages of RF between the study (80/201 (39%)) and control (29/2803 (1%)) groups (p < 0.05). The RF occur when the aorta flow rate (left heart) is reduced to 60% by CFD stimulation. Pearson correlation analysis showed significant correlations between flow rate and wall shear stress(WSS) (r = .883, p = 0.047) variables at the AI. CONCLUSION Volumetric flow rate of AO or left heart was the main component of the cause of RF. The hemodynamics of the cardiovascular system have highly complex behavior hinge on the turbulent nature of circulating blood flow.
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Affiliation(s)
- Zhuo Chen
- Echocardiography Medical Center, Maternal-Fetal Medicine center in Fetal Heart Disease, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Hongkai Zhao
- School of Energy and Power Engineering, Beijing University of Aeronautics and Astronautics, Beijing, China
| | - Ying Zhao
- Echocardiography Medical Center, Maternal-Fetal Medicine center in Fetal Heart Disease, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Jiancheng Han
- Echocardiography Medical Center, Maternal-Fetal Medicine center in Fetal Heart Disease, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Xu Yang
- Echocardiography Medical Center, Maternal-Fetal Medicine center in Fetal Heart Disease, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Amy Throckmorton
- BioCirc Research Laboratory, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania, USA
| | - Zhenglun Wei
- Department of Biomedical Engineering, University of Massachusetts Lowell, Lowell, Massachusetts, USA
| | - Shuping Ge
- Geisinger Heart and Vascular Institute, Geisinger Medical Center, Danville, Pennsylvania, USA
| | - Yihua He
- Echocardiography Medical Center, Maternal-Fetal Medicine center in Fetal Heart Disease, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
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Armour CH, Guo B, Saitta S, Pirola S, Liu Y, Dong Z, Xu XY. Evaluation and verification of patient-specific modelling of type B aortic dissection. Comput Biol Med 2022; 140:105053. [PMID: 34847383 DOI: 10.1016/j.compbiomed.2021.105053] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 02/07/2023]
Abstract
Quantitative assessment of the complex hemodynamic environment in type B aortic dissection (TBAD) through computational fluid dynamics (CFD) simulations can provide detailed insights into the disease and its progression. As imaging and computational technologies have advanced, methodologies have been developed to increase the accuracy and physiological relevance of CFD simulations. This study presents a patient-specific workflow to simulate blood flow in TBAD, utilising the maximum amount of in vivo data available in the form of CT images, 4D-flow MRI and invasive Doppler-wire pressure measurements, to implement the recommended current best practice methodologies in terms of patient-specific geometry and boundary conditions. The study aimed to evaluate and verify this workflow through detailed qualitative and quantitative comparisons of the CFD and in vivo data. Based on data acquired from five TBAD patients, a range of essential model inputs was obtained, including inlet flow waveforms and 3-element Windkessel model parameters, which can be utilised in further studies where in vivo flow data is not available. Local and global analysis showed good consistency between CFD results and 4D-MRI data, with the maximum velocity in the primary entry tear differing by up to 0.3 m/s, and 80% of the analysed regions achieving moderate or strong correlations between the predicted and in vivo velocities. CFD predicted pressures were generally well matched to the Doppler-wire measurements, with some deviation in peak systolic values. Overall, this study presents a validated comprehensive workflow with extensive data for CFD simulation of TBAD.
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Affiliation(s)
- Chlöe H Armour
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Baolei Guo
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
| | - Simone Saitta
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK; Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Selene Pirola
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Yifan Liu
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
| | - Zhihui Dong
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China.
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK.
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Manchester EL, Pirola S, Salmasi MY, O'Regan DP, Athanasiou T, Xu XY. Evaluation of Computational Methodologies for Accurate Prediction of Wall Shear Stress and Turbulence Parameters in a Patient-Specific Aorta. Front Bioeng Biotechnol 2022; 10:836611. [PMID: 35402418 PMCID: PMC8987126 DOI: 10.3389/fbioe.2022.836611] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 03/07/2022] [Indexed: 11/21/2022] Open
Abstract
Background: Recent studies suggest that blood flow in main arteries is intrinsically disturbed, even under healthy conditions. Despite this, many computational fluid dynamics (CFD) analyses of aortic haemodynamics make the assumption of laminar flow, and best practices surrounding appropriate modelling choices are lacking. This study aims to address this gap by evaluating different modelling and post-processing approaches in simulations of a patient-specific aorta. Methods: Magnetic resonance imaging (MRI) and 4D flow MRI from a patient with aortic valve stenosis were used to reconstruct the aortic geometry and derive patient-specific inlet and outlet boundary conditions. Three different computational approaches were considered based on assumed laminar or assumed disturbed flow states including low-resolution laminar (LR-Laminar), high-resolution laminar (HR-Laminar) and large-eddy simulation (LES). Each simulation was ran for 30 cardiac cycles and post-processing was conducted on either the final cardiac cycle, or using a phase-averaged approach which utilised all 30 simulated cycles. Model capabilities were evaluated in terms of mean and turbulence-based parameters. Results: All simulation types, regardless of post-processing approach could correctly predict velocity values and flow patterns throughout the aorta. Lower resolution simulations could not accurately predict gradient-derived parameters including wall shear stress and viscous energy loss (largest differences up to 44.6% and 130.3%, respectively), although phase-averaging these parameters improved predictions. The HR-Laminar simulation produced more comparable results to LES with largest differences in wall shear stress and viscous energy loss parameters up to 5.1% and 11.6%, respectively. Laminar-based parameters were better estimated than turbulence-based parameters. Conclusion: Our findings suggest that well-resolved laminar simulations can accurately predict many laminar-based parameters in disturbed flows, but there is no clear benefit to running a HR-Laminar simulation over an LES simulation based on their comparable computational cost. Additionally, post-processing "typical" laminar simulation results with a phase-averaged approach is a simple and cost-effective way to improve accuracy of lower-resolution simulation results.
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Affiliation(s)
| | - Selene Pirola
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
| | - Mohammad Yousuf Salmasi
- Department of Surgery and Cancer, Imperial College London, St Mary's Hospital, London, United Kingdom
| | - Declan P O'Regan
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Thanos Athanasiou
- Department of Surgery and Cancer, Imperial College London, St Mary's Hospital, London, United Kingdom
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
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32
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Dai Z, Iguchi N, Takamisawa I, Takayama M, Nanasato M, Kanisawa M, Mizuno N, Miyazaki S, Isobe M. Alcohol septal ablation markedly reduces energy loss in hypertrophic cardiomyopathy with left ventricular outflow tract obstruction: A four-dimensional flow cardiac magnetic resonance study. IJC HEART & VASCULATURE 2021; 37:100886. [PMID: 34692989 PMCID: PMC8515238 DOI: 10.1016/j.ijcha.2021.100886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/23/2021] [Accepted: 09/26/2021] [Indexed: 11/16/2022]
Abstract
Background Functional follow-up modalities of hypertrophic cardiomyopathy (HCM) with left ventricular (LV) outflow tract obstruction (LVOTO) subjected to alcohol septal ablation (ASA) are limited. Methods This retrospective cohort study included patients of HCM with LVOTO who underwent ASA and four-dimensional (4D) flow cardiac magnetic resonance imaging (MRI) both before and after ASA. We analyzed energy loss in one cardiac cycle within the three-chamber plane of the LV and aortic root, and compared between pre- and post-ASA measurements. Results Of the 26 included patients, 10 (39%) were male, and median age was 71 (interquartile range 58–78) years. ASA significantly reduced not only LVOT pressure gradient (70 [19–50] to 9 [3–16], P < 0.001), but also energy loss during one cardiac cycle within the three-chamber plane of the LV and aortic root (80 [65–99] to 56 [45–70], P < 0.001). A linear association was observed between the reductions of energy loss and pressure gradient (R2 = 0.58, P < 0.001). Conclusions ASA significantly reduced energy loss within the LV and aortic root as quantified by 4D flow MRI, reflecting the decreased cardiac workload. This approach is a promising candidate for serial functional follow-up in patients undergoing ASA.
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Key Words
- 4D flow MRI
- 4D, four-dimensional
- ASA, alcohol septal ablation
- Alcohol septal ablation
- Energy loss
- HCM, hypertrophic cardiomyopathy
- Hypertrophic cardiomyopathy
- LV, left ventricle/left ventricular
- LVOT, left ventricular outflow tract
- LVOTO, left ventricular outflow tract obstruction
- Left ventricular outflow tract obstruction
- MRI, magnetic resonance imaging
- NYHA, New York Heart Association
- ROI, region of interest
- TTE, transthoracic echocardiography
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Affiliation(s)
- Zhehao Dai
- Department of Cardiology, Sakakibara Heart Institute, 3-16-1 Asahi-cho, Fuchu, Tokyo 183-0003, Japan.,Department of Cardiovascular Medicine, The University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Nobuo Iguchi
- Department of Cardiology, Sakakibara Heart Institute, 3-16-1 Asahi-cho, Fuchu, Tokyo 183-0003, Japan.,Department of Radiology, Sakakibara Heart Institute, 3-16-1 Asahi-cho, Fuchu, Tokyo 183-0003, Japan
| | - Itaru Takamisawa
- Department of Cardiology, Sakakibara Heart Institute, 3-16-1 Asahi-cho, Fuchu, Tokyo 183-0003, Japan
| | - Morimasa Takayama
- Department of Cardiology, Sakakibara Heart Institute, 3-16-1 Asahi-cho, Fuchu, Tokyo 183-0003, Japan
| | - Mamoru Nanasato
- Department of Cardiology, Sakakibara Heart Institute, 3-16-1 Asahi-cho, Fuchu, Tokyo 183-0003, Japan
| | - Mitsuru Kanisawa
- Department of Radiology, Sakakibara Heart Institute, 3-16-1 Asahi-cho, Fuchu, Tokyo 183-0003, Japan
| | - Naokazu Mizuno
- Department of Radiology, Sakakibara Heart Institute, 3-16-1 Asahi-cho, Fuchu, Tokyo 183-0003, Japan
| | - Shohei Miyazaki
- Cardio Flow Design Inc., 22-3 Ichibancho, Chiyoda-ku, Tokyo 102-0082, Japan
| | - Mitsuaki Isobe
- Sakakibara Heart Institute, 3-16-1 Asahi-cho, Fuchu, Tokyo 183-0003, Japan
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33
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Stokes C, Bonfanti M, Li Z, Xiong J, Chen D, Balabani S, Díaz-Zuccarini V. A novel MRI-based data fusion methodology for efficient, personalised, compliant simulations of aortic haemodynamics. J Biomech 2021; 129:110793. [PMID: 34715606 PMCID: PMC8907869 DOI: 10.1016/j.jbiomech.2021.110793] [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: 05/07/2021] [Revised: 08/24/2021] [Accepted: 09/30/2021] [Indexed: 01/24/2023]
Abstract
We present a novel, cost-efficient methodology to simulate aortic haemodynamics in a patient-specific, compliant aorta using an MRI data fusion process. Based on a previously-developed Moving Boundary Method, this technique circumvents the high computational cost and numerous structural modelling assumptions required by traditional Fluid-Structure Interaction techniques. Without the need for Computed Tomography (CT) data, the MRI images required to construct the simulation can be obtained during a single imaging session. Black Blood MR Angiography and 2D Cine-MRI data were used to reconstruct the luminal geometry and calibrate wall movement specifically to each region of the aorta. 4D-Flow MRI and non-invasive pressure measurements informed patient-specific inlet and outlet boundary conditions. Luminal area closely matched 2D Cine-MRI measurements with a mean error of less than 4.6% across the cardiac cycle, while physiological pressure and flow distributions were simulated to within 3.3% of patient-specific targets. Moderate agreement with 4D-Flow MRI velocity data was observed. Despite lower peak velocity, an equivalent rigid-wall simulation predicted a mean Time-Averaged Wall Shear Stress (TAWSS) 13% higher than the compliant simulation. The agreement observed between compliant simulation results and MRI data is testament to the accuracy and efficiency of this MRI-based simulation technique.
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Affiliation(s)
- Catriona Stokes
- Mechanical Engineering Department, Roberts Engineering Building, University College London, Torrington Place, London, WC1E 7JE, United Kingdom; Wellcome/EPSRC Centre for Interventional and Surgical Sciences (WEISS), Charles Bell House, London, W1W 7TY, United Kingdom.
| | - Mirko Bonfanti
- Mechanical Engineering Department, Roberts Engineering Building, University College London, Torrington Place, London, WC1E 7JE, United Kingdom; Wellcome/EPSRC Centre for Interventional and Surgical Sciences (WEISS), Charles Bell House, London, W1W 7TY, United Kingdom.
| | - Zeyan Li
- School of Life Science, Beijing Institute of Technology, Beijing, China.
| | - Jiang Xiong
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China.
| | - Duanduan Chen
- School of Life Science, Beijing Institute of Technology, Beijing, China.
| | - Stavroula Balabani
- Mechanical Engineering Department, Roberts Engineering Building, University College London, Torrington Place, London, WC1E 7JE, United Kingdom; Wellcome/EPSRC Centre for Interventional and Surgical Sciences (WEISS), Charles Bell House, London, W1W 7TY, United Kingdom.
| | - Vanessa Díaz-Zuccarini
- Mechanical Engineering Department, Roberts Engineering Building, University College London, Torrington Place, London, WC1E 7JE, United Kingdom; Wellcome/EPSRC Centre for Interventional and Surgical Sciences (WEISS), Charles Bell House, London, W1W 7TY, United Kingdom.
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34
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Yazdi SG, Docherty PD, Williamson PN, Jermy M, Kabaliuk N, Khanafer A, Geoghegan PH. In vitro pulsatile flow study in compliant and rigid ascending aorta phantoms by stereo particle image velocimetry. Med Eng Phys 2021; 96:81-90. [PMID: 34565556 DOI: 10.1016/j.medengphy.2021.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 08/05/2021] [Accepted: 08/31/2021] [Indexed: 10/20/2022]
Abstract
The aorta is a high risk region for cardiovascular disease (CVD). Haemodynamic patterns leading to CVD are not well established despite numerous experimental and numerical studies. Most overlook effects of arterial compliance and pulsatile flow. However, rigid wall assumptions can lead to overestimation of wall shear stress; a key CVD determinant. This work investigates the effect of compliance on aortic arch haemodynamics experiencing pulsatility. Rigid and compliant phantoms of the arch and brachiocephalic branch (BCA) were manufactured. Stereoscopic particle image velocimetry was used to observe velocity fields. Higher velocity magnitude was observed in the rigid BCA during acceleration. However, during deceleration, the compliant phantom experienced higher velocity. During deceleration, a low velocity region initiated and increased in size in the BCA of both phantoms with irregular shape in the compliant. At mid-deceleration, considerably larger recirculation was observed under compliance compared to rigid. Another recirculation region formed and increased in size on the inner wall of the arch in the compliant during late deceleration, but not rigid. The recirculation regions witnessed identify as high risk areas for atherosclerosis formation by a previous ex-vivo study. The results demonstrate necessity of compliance and pulsatility in haemodynamic studies to obtain highly relevant clinical outcomes.
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Affiliation(s)
- Sina G Yazdi
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Paul D Docherty
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Petra N Williamson
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Mark Jermy
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Natalia Kabaliuk
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Adib Khanafer
- Vascular, Endovascular, & Renal Transplant Unit Christchurch Hospital, Canterbury District Health Board, Riccarton Avenue, Christchurch 8053, New Zealand; Christchurch School of Medicine, University of Otago, New Zealand
| | - Patrick H Geoghegan
- Department of Mechanical, Biomedical and Design, College of Engineering and Physical Sciences Aston University, Birmingham, B4 7ET, England; Department of Mechanical and Industrial Engineering, University of South Africa, Johannesburg, South Africa.
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35
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Gao Q, Liu X, Wang H, Wu P, Jin M, Wei R, Wang W, Niu Z, Zhao S, Li F. Optimization of 4D flow MRI velocity field in the aorta with divergence-free smoothing. Med Biol Eng Comput 2021; 59:2237-2252. [PMID: 34528164 DOI: 10.1007/s11517-021-02417-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 07/14/2021] [Indexed: 10/20/2022]
Abstract
Divergence-free smoothing with wall treatment (DFSwt) method is proposed for processing with four-dimensional (4D) flow magnetic resonance imaging (MRI) data of blood flows to enhance the quality of flow field with physical constraints. The new method satisfies the no-slip wall boundary condition and applies wall function of velocity profile for better estimating the velocity gradient in the near-wall region, and consequently improved wall shear stress (WSS) calculation against the issue of coarse resolution of 4D flow MRI. In the first testing case, blood flow field obtained from 4D flow MRI is well smoothed by DFSwt method. A great consistency is observed between the post-processed 4D flow MRI data and the computational fluid dynamics (CFD) data in the interested velocity field. WSS has an apparent improvement due to the proposed near-wall treatment with special wall function comparing to the result from original 4D flow MRI data or the DFS-processed data with no wall function. The other five cases also show the same performance that smoothed velocity field and improved WSS estimation are achieved on 4D flow MRI data optimized by DFSwt. The improvements will benefit the study of hemodynamics regarding the determination of location or the potential possibility of lesions.
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Affiliation(s)
- Qi Gao
- School of Aeronautics and Astronautics, Zhejiang University, Yuquan Campus, 38 Zheda Road, Xihu District, Hangzhou, 310027, China.
| | - Xingli Liu
- Hangzhou Shengshi Technology Co., Ltd., Hangzhou, China
| | - Hongping Wang
- The State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
| | - Peng Wu
- Artificial Organ Technology Lab, Bio-manufacturing Research Centre, School of Mechanical and Electric Engineering, Soochow University, Suzhou, China
| | - Mansu Jin
- Hangzhou Shengshi Technology Co., Ltd., Hangzhou, China
| | - RunJie Wei
- Hangzhou Shengshi Technology Co., Ltd., Hangzhou, China
| | - Wei Wang
- Department of Structural Heart Disease, Chinese Academy of Medical Sciences & Fuwai Hospital; State Key Laboratory of Cardiovascular Disease, Peking Union Medical College, 167 Beilishi Road, Xicheng District, 100037, Beijing, China
| | - Zhaozhuo Niu
- Cardiac Surgery, Qingdao Municipal Hospital, Qingdao, China
| | - Shihua Zhao
- Department of Magnetic Resonance Imaging, Chinese Academy of Medical Sciences & Fuwai Hospital, Peking Union Medical College, 167 Beilishi Road, Xicheng District, 100037, Beijing, China.
| | - Fei Li
- Department of Structural Heart Disease, Chinese Academy of Medical Sciences & Fuwai Hospital; State Key Laboratory of Cardiovascular Disease, Peking Union Medical College, 167 Beilishi Road, Xicheng District, 100037, Beijing, China. .,Department of Cardiac Surgery, Peking University First Hospital, Beijing, China.
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36
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Mandell JG, Loke YH, Mass PN, Cleveland V, Delaney M, Opfermann J, Aslan S, Krieger A, Hibino N, Olivieri LJ. Altered hemodynamics by 4D flow cardiovascular magnetic resonance predict exercise intolerance in repaired coarctation of the aorta: an in vitro study. J Cardiovasc Magn Reson 2021; 23:99. [PMID: 34482836 PMCID: PMC8420072 DOI: 10.1186/s12968-021-00796-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 07/14/2021] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Coarctation of the aorta (CoA) is associated with decreased exercise capacity despite successful repair. Altered flow patterns have been identified due to abnormal aortic arch geometry. Our previous work demonstrated aorta size mismatch to be associated with exercise intolerance in this population. In this study, we studied aortic flow patterns during simulations of exercise in repaired CoA using 4D flow cardiovascular magnetic resonance (CMR) using aortic replicas connected to an in vitro flow pump and correlated findings with exercise stress test results to identify biomarkers of exercise intolerance. METHODS Patients with CoA repair were retrospectively analyzed after CMR and exercise stress test. Each aorta was manually segmented and 3D printed. Pressure gradient measurements from ascending aorta (AAo) to descending aorta (DAo) and 4D flow CMR were performed during simulations of rest and exercise using a mock circulatory flow loop. Changes in wall shear stress (WSS) and secondary flow formation (vorticity and helicity) from rest to exercise were quantified, as well as estimated DAo Reynolds number. Parameters were correlated with percent predicted peak oxygen consumption (VO2max) and aorta size mismatch (DAAo/DDAo). RESULTS Fifteen patients were identified (VO2max 47 to 126% predicted). Pressure gradient did not correlate with VO2max at rest or exercise. VO2max correlated positively with the change in peak vorticity (R = 0.55, p = 0.03), peak helicity (R = 0.54, p = 0.04), peak WSS in the AAo (R = 0.68, p = 0.005) and negatively with peak WSS in the DAo (R = - 0.57, p = 0.03) from rest to exercise. DAAo/DDAo correlated strongly with change in vorticity (R = - 0.38, p = 0.01), helicity (R = - 0.66, p = 0.007), and WSS in the AAo (R = - 0.73, p = 0.002) and DAo (R = 0.58, p = 0.02). Estimated DAo Reynolds number negatively correlated with VO2max for exercise (R = - 0.59, p = 0.02), but not rest (R = - 0.28, p = 0.31). Visualization of streamline patterns demonstrated more secondary flow formation in aortic arches with better exercise capacity, larger DAo, and lower Reynolds number. CONCLUSIONS There are important associations between secondary flow characteristics and exercise capacity in repaired CoA that are not captured by traditional pressure gradient, likely due to increased turbulence and inefficient flow. These 4D flow CMR parameters are a target of investigation to identify optimal aortic arch geometry and improve long term clinical outcomes after CoA repair.
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Affiliation(s)
- Jason G Mandell
- Division of Cardiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA.
| | - Yue-Hin Loke
- Division of Cardiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA
| | - Paige N Mass
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA
| | - Vincent Cleveland
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA
| | - Marc Delaney
- Division of Cardiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA
| | - Justin Opfermann
- Department of Mechanical Engineering, Johns Hopkins University, Latrobe Hall 223, 3400 North Charles St, Baltimore, MD, 21218, USA
| | - Seda Aslan
- Department of Mechanical Engineering, Johns Hopkins University, Latrobe Hall 223, 3400 North Charles St, Baltimore, MD, 21218, USA
| | - Axel Krieger
- Department of Mechanical Engineering, Johns Hopkins University, Latrobe Hall 223, 3400 North Charles St, Baltimore, MD, 21218, USA
| | - Narutoshi Hibino
- Section of Cardiac Surgery, Department of Surgery, University of Chicago, 5841 S Maryland Avenue, Chicago, IL, 60637, USA
- Section of Cardiac Surgery, Department of Surgery, Advocate Children's Hospital, 4440 West 95th Street, Oak Lawn, IL, 60453, USA
| | - Laura J Olivieri
- Division of Cardiology, Children's National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA
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37
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Perinajová R, Juffermans JF, Mercado JL, Aben JP, Ledoux L, Westenberg JJM, Lamb HJ, Kenjereš S. Assessment of turbulent blood flow and wall shear stress in aortic coarctation using image-based simulations. Biomed Eng Online 2021; 20:84. [PMID: 34419047 PMCID: PMC8379896 DOI: 10.1186/s12938-021-00921-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/07/2021] [Indexed: 01/23/2023] Open
Abstract
In this study, we analyzed turbulent flows through a phantom (a 180[Formula: see text] bend with narrowing) at peak systole and a patient-specific coarctation of the aorta (CoA), with a pulsating flow, using magnetic resonance imaging (MRI) and computational fluid dynamics (CFD). For MRI, a 4D-flow MRI is performed using a 3T scanner. For CFD, the standard [Formula: see text], shear stress transport [Formula: see text], and Reynolds stress (RSM) models are applied. A good agreement between measured and simulated velocity is obtained for the phantom, especially for CFD with RSM. The wall shear stress (WSS) shows significant differences between CFD and MRI in absolute values, due to the limited near-wall resolution of MRI. However, normalized WSS shows qualitatively very similar distributions of the local values between MRI and CFD. Finally, a direct comparison between in vivo 4D-flow MRI and CFD with the RSM turbulence model is performed in the CoA. MRI can properly identify regions with locally elevated or suppressed WSS. If the exact values of the WSS are necessary, CFD is the preferred method. For future applications, we recommend the use of the combined MRI/CFD method for analysis and evaluation of the local flow patterns and WSS in the aorta.
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Affiliation(s)
- Romana Perinajová
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands. .,J.M. Burgerscentrum Research School for Fluid Mechanics, Delft, The Netherlands.
| | - Joe F Juffermans
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jonhatan Lorenzo Mercado
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands
| | | | - Leon Ledoux
- Pie Medical Imaging BV, Maastricht, The Netherlands
| | - Jos J M Westenberg
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Hildo J Lamb
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Saša Kenjereš
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands.,J.M. Burgerscentrum Research School for Fluid Mechanics, Delft, The Netherlands
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Manchester EL, Pirola S, Salmasi MY, O'Regan DP, Athanasiou T, Xu XY. Analysis of Turbulence Effects in a Patient-Specific Aorta with Aortic Valve Stenosis. Cardiovasc Eng Technol 2021; 12:438-453. [PMID: 33829405 PMCID: PMC8354935 DOI: 10.1007/s13239-021-00536-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 03/18/2021] [Indexed: 10/26/2022]
Abstract
Blood flow in the aorta is often assumed laminar, however aortic valve pathologies may induce transition to turbulence and our understanding of turbulence effects is incomplete. The aim of the study was to provide a detailed analysis of turbulence effects in aortic valve stenosis (AVS). METHODS Large-eddy simulation (LES) of flow through a patient-specific aorta with AVS was conducted. Magnetic resonance imaging (MRI) was performed and used for geometric reconstruction and patient-specific boundary conditions. Computed velocity field was compared with 4D flow MRI to check qualitative and quantitative consistency. The effect of turbulence was evaluated in terms of fluctuating kinetic energy, turbulence-related wall shear stress (WSS) and energy loss. RESULTS Our analysis suggested that turbulence was induced by a combination of a high velocity jet impinging on the arterial wall and a dilated ascending aorta which provided sufficient space for turbulence to develop. Turbulent WSS contributed to 40% of the total WSS in the ascending aorta and 38% in the entire aorta. Viscous and turbulent irreversible energy losses accounted for 3.9 and 2.7% of the total stroke work, respectively. CONCLUSIONS This study demonstrates the importance of turbulence in assessing aortic haemodynamics in a patient with AVS. Neglecting the turbulent contribution to WSS could potentially result in a significant underestimation of the total WSS. Further work is warranted to extend the analysis to more AVS cases and patients with other aortic valve diseases.
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Affiliation(s)
- Emily L Manchester
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Selene Pirola
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Mohammad Yousuf Salmasi
- Department of Surgery and Cancer, St Mary's Hospital, Imperial College London, London, W2 1NY, UK
| | - Declan P O'Regan
- Hammersmith Hospital, MRC London Institute of Medical Sciences Imperial College London, London, W12 0HS, UK
| | - Thanos Athanasiou
- Department of Surgery and Cancer, St Mary's Hospital, Imperial College London, London, W2 1NY, UK
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
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Hohri Y, Itatani K, Matsuo A, Komori Y, Okamoto T, Goto T, Kobayashi T, Hiramatsu T, Miyazaki S, Nishino T, Yaku H. Estimating the Haemodynamic Streamline Vena Contracta as the Effective Orifice Area Measured from Reconstructed Multislice Phase-contrast MR Images for Patients with Moderately Accelerated Aortic Stenosis. Magn Reson Med Sci 2021; 21:569-582. [PMID: 34334586 DOI: 10.2463/mrms.mp.2021-0001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE In aortic stenosis (AS), the discrepancy between moderately accelerated flow and effective orifice area (EOA) continues to pose a challenge. We developed a method of measuring the vena contracta area as hemodynamic EOA using cardiac MRI focusing on AS patients with a moderately accelerated flow to solve the problem that AS severity can currently be determined only by echocardiography. METHODS We investigated 40 patients with a peak transvalvular velocity > 3.0 m/s on transthoracic echocardiography (TTE). The patients were divided into highly accelerated and moderately accelerated AS groups according to whether or not the peak transvalvular velocity was ≥ 4.0 m/s. From the multislice 2D cine phase-contrast MRI data, the cross-sectional area of the vena contracta of the reconstructed streamline in the Valsalva sinus was defined as MRI-EOAs. Patient symptoms and echocardiography data, including EOA (defined as TTE-EOA), were derived from the continuity equation using TTE. RESULTS All participants in the highly accelerated AS group (n = 19) showed a peak velocity ≥ 4.0 m/s in MRI. Eleven patients in the moderately accelerated AS group (n = 21) had a TTE-EOA < 1.00 cm2. In the moderately accelerated AS group, MRI-EOAs demonstrated a strong correlation with TTE-EOAs (r = 0.76, P < 0.01). Meanwhile, in the highly accelerated AS group, MRI-EOAs demonstrated positivity but a moderate correlation with TTE-EOAs (r = 0.63, P = 0.004). MRI-EOAs were overestimated compared to TTE-EOAs. In terms of the moderately accelerated AS group, the best cut-off value for MRI-EOAs was < 1.23 cm2, compatible with TTE-EOAs < 1.00 cm2, with an excellent prediction of the New York Heart Association classification ≥ III (sensitivity 87.5%, specificity 76.9%). CONCLUSION MRI-EOAs may be an alternative to conventional echocardiography for patients with moderately accelerated AS, especially those with discordant echocardiographic parameters.
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Affiliation(s)
- Yu Hohri
- Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine
| | | | - Akiko Matsuo
- Department of Cardiology, Japanese Red Cross Kyoto Daini Hospital
| | | | - Takeshi Okamoto
- Department of Radiology, Japanese Red Cross Kyoto Daini Hospital
| | - Tomoyuki Goto
- Department of Cardiovascular Surgery, Japanese Red Cross Kyoto Daini Hospital
| | - Takuma Kobayashi
- Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine
| | - Takeshi Hiramatsu
- Department of Cardiovascular Surgery, Tokyo Women's Medical University Yachiyo Medical Center
| | | | | | - Hitoshi Yaku
- Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine
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40
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Komoriyama H, Kamiya K, Nagai T, Oyama-Manabe N, Tsuneta S, Kobayashi Y, Kato Y, Sarashina M, Omote K, Konishi T, Sato T, Tsujinaga S, Iwano H, Shingu Y, Wakasa S, Anzai T. Blood flow dynamics with four-dimensional flow cardiovascular magnetic resonance in patients with aortic stenosis before and after transcatheter aortic valve replacement. J Cardiovasc Magn Reson 2021; 23:81. [PMID: 34176516 PMCID: PMC8237445 DOI: 10.1186/s12968-021-00771-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 05/04/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pre- and post-procedural hemodynamic changes which could affect adverse outcomes in aortic stenosis (AS) patients who undergo transcatheter aortic valve replacement (TAVR) have not been well investigated. Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) enables accurate analysis of blood flow dynamics such as flow velocity, flow pattern, wall shear stress (WSS), and energy loss (EL). We sought to examine the changes in blood flow dynamics of patients with severe AS who underwent TAVR. METHODS We examined 32 consecutive severe AS patients who underwent TAVR between May 2018 and June 2019 (17 men, 82 ± 5 years, median left ventricular ejection fraction 61%, 6 self-expanding valve), after excluding those without CMR because of a contraindication or inadequate imaging from the analyses. We analyzed blood flow patterns, WSS and EL in the ascending aorta (AAo), and those changes before and after TAVR using 4D flow CMR. RESULTS After TAVR, semi-quantified helical flow in the AAo was significantly decreased (1.4 ± 0.6 vs. 1.9 ± 0.8, P = 0.002), whereas vortical flow and eccentricity showed no significant changes. WSS along the ascending aortic circumference was significantly decreased in the left (P = 0.038) and left anterior (P = 0.033) wall at the basal level, right posterior (P = 0.011) and left (P = 0.010) wall at the middle level, and right (P = 0.012), left posterior (P = 0.019) and left anterior (P = 0.028) wall at the upper level. EL in the AAo was significantly decreased (15.6 [10.8-25.1 vs. 25.8 [18.6-36.2]] mW, P = 0.012). Furthermore, a significant negative correlation was observed between EL and effective orifice area index after TAVR (r = - 0.38, P = 0.034). CONCLUSIONS In severe AS patients undergoing TAVR, 4D flow CMR demonstrates that TAVR improves blood flow dynamics, especially when a larger effective orifice area index is obtained.
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Affiliation(s)
- Hirokazu Komoriyama
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Kiwamu Kamiya
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Toshiyuki Nagai
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan.
| | - Noriko Oyama-Manabe
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Kita 14, Nishi 5, Kita-ku, Sapporo, Hokkaido, 060-8648, Japan
| | - Satonori Tsuneta
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Kita 14, Nishi 5, Kita-ku, Sapporo, Hokkaido, 060-8648, Japan
| | - Yuta Kobayashi
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Yoshiya Kato
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Miwa Sarashina
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Kazunori Omote
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Takao Konishi
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Takuma Sato
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Shingo Tsujinaga
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Hiroyuki Iwano
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Yasushige Shingu
- Department of Cardiovascular and Thoracic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Satoru Wakasa
- Department of Cardiovascular and Thoracic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Toshihisa Anzai
- Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
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Oyama-Manabe N, Aikawa T, Tsuneta S, Manabe O. Clinical Applications of 4D Flow MR Imaging in Aortic Valvular and Congenital Heart Disease. Magn Reson Med Sci 2021; 21:319-326. [PMID: 34176866 DOI: 10.2463/mrms.rev.2021-0030] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
4D flow MRI allows time-resolved 3D velocity-encoded phase-contrast imaging for 3D visualization and quantification of aortic and intracardiac flow. Radiologists should be familiar with the principles of 4D flow MRI and methods for evaluating blood flow qualitatively and quantitatively. The most substantial benefits of 4D flow MRI are that it enables the simultaneous comprehensive assessment of different vessels, and that retrospective analysis can be achieved in all vessels in any direction in the field of view, which is especially beneficial for patients with complicated congenital heart disease (CHD). For aortic valvular diseases, new parameters such as wall shear stress and energy loss may provide new prognostic values for 4D flow MRI. In this review, we introduce the clinical applications of 4D flow MRI for the visualization of blood flow and quantification of hemodynamic metrics in the setting of aortic valvular disease and CHD, including intracardiac shunt and coronary artery anomaly.
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Affiliation(s)
| | - Tadao Aikawa
- Department of Radiology, Jichi Medical University Saitama Medical Center
| | - Satonori Tsuneta
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital
| | - Osamu Manabe
- Department of Radiology, Jichi Medical University Saitama Medical Center
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Circulation derived from 4D flow MRI correlates with right ventricular dysfunction in patients with tetralogy of Fallot. Sci Rep 2021; 11:11623. [PMID: 34079023 PMCID: PMC8172849 DOI: 10.1038/s41598-021-91125-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 05/21/2021] [Indexed: 11/28/2022] Open
Abstract
We used 4D-flow MRI to investigate circulation, an area integral of vorticity, in the main pulmonary artery (MPA) as a new hemodynamic parameter for assessing patients with a repaired Tetralogy of Fallot (TOF). We evaluated the relationship between circulation, right ventricular (RV) function and the pulmonary regurgitant fraction (PRF). Twenty patients with a repaired TOF underwent cardiac MRI. Flow-sensitive 3D-gradient sequences were used to obtain 4D-flow images. Vortex formation in the MPA was visualized, with short-axis and longitudinal vorticities calculated by software specialized for 4D flow. The RV indexed end-diastolic/end-systolic volumes (RVEDVi/RVESVi) and RV ejection fraction (RVEF) were measured by cine MRI. The PR fraction (PRF) and MPA area were measured by 2D phase-contrast MRI. Spearman ρ values were determined to assess the relationships between circulation, RV function, and PRF. Vortex formation in the MPA occurred in 15 of 20 patients (75%). The longitudinal circulation (11.7 ± 5.1 m2/s) was correlated with the RVEF (ρ = − 0.85, p = 0.0002), RVEDVi (ρ = 0.62, p = 0.03), and RVESVi (ρ = 0.76, p = 0.003) after adjusting for the MPA size. The short-axis circulation (9.4 ± 3.4 m2/s) in the proximal MPA was positively correlated with the MPA area (ρ = 0.61, p = 0.004). The relationships between the PRF and circulation or RV function were not significant. Increased longitudinal circulation in the MPA, as demonstrated by circulation analysis using 4D flow MRI, was related to RV dysfunction in patients with a repaired TOF.
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Wasson EM, Dubbin K, Moya ML. Go with the flow: modeling unique biological flows in engineered in vitro platforms. LAB ON A CHIP 2021; 21:2095-2120. [PMID: 34008661 DOI: 10.1039/d1lc00014d] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Interest in recapitulating in vivo phenomena in vitro using organ-on-a-chip technology has grown rapidly and with it, attention to the types of fluid flow experienced in the body has followed suit. These platforms offer distinct advantages over in vivo models with regards to human relevance, cost, and control of inputs (e.g., controlled manipulation of biomechanical cues from fluid perfusion). Given the critical role biophysical forces play in several tissues and organs, it is therefore imperative that engineered in vitro platforms capture the complex, unique flow profiles experienced in the body that are intimately tied with organ function. In this review, we outline the complex and unique flow regimes experienced by three different organ systems: blood vasculature, lymphatic vasculature, and the intestinal system. We highlight current state-of-the-art platforms that strive to replicate physiological flows within engineered tissues while introducing potential limitations in current approaches.
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Affiliation(s)
- Elisa M Wasson
- Material Engineering Division, Lawrence Livermore National Laboratory, 7000 East Ave L-222, Livermore, CA 94551, USA.
| | - Karen Dubbin
- Material Engineering Division, Lawrence Livermore National Laboratory, 7000 East Ave L-222, Livermore, CA 94551, USA.
| | - Monica L Moya
- Material Engineering Division, Lawrence Livermore National Laboratory, 7000 East Ave L-222, Livermore, CA 94551, USA.
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Rabin A, Palacio D, Saqib N, Bar-Yoseph P, Weiss D, Afifi RO. Aortic aneurysms and dissections: Unmet needs from physicians and engineers perspectives. J Biomech 2021; 122:110461. [PMID: 33901933 DOI: 10.1016/j.jbiomech.2021.110461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 03/31/2021] [Indexed: 10/21/2022]
Abstract
The treatment of aortic disease is complex, requiring cardiothoracic and vascular surgeons to make pre-, post- and intraoperative decisions directly influencing patient survival and well-being. Despite tremendous advancement in vascular surgery and endovascular techniques in the last two decades, along with the abundance of research in the field, many unmet needs and unanswered questions remain. Tight collaboration between engineers and physicians is a keystone in translating new tools, techniques, and devices into practice. Here, we have gathered our perspective, as physicians and engineers, in several pressing issues associated with the diagnosis and treatment of aortic aneurysms and dissection, referring to the current knowledge and practice, signifying unmet needs as well as future directions.
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Affiliation(s)
- Asaf Rabin
- Department of Vascular and Endovascular Surgery Unit, B. Padeh M.C, Poriya, Israel.
| | - Diana Palacio
- Cardiothoracic Imaging Division, Department of Medical Imaging, The University of Arizona Banner Medical Center, Tucson, AZ, USA
| | - Naveed Saqib
- Department of Cardiothoracic and Vascular Surgery, McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA
| | - Pinhas Bar-Yoseph
- Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Dar Weiss
- Department of Biomedical Engineering, Yale university, CT, USA
| | - Rana O Afifi
- Department of Cardiothoracic and Vascular Surgery, McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA
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Wüstenhagen C, John K, Langner S, Brede M, Grundmann S, Bruschewski M. CFD validation using in-vitro MRI velocity data - Methods for data matching and CFD error quantification. Comput Biol Med 2021; 131:104230. [PMID: 33545507 DOI: 10.1016/j.compbiomed.2021.104230] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 01/15/2021] [Accepted: 01/16/2021] [Indexed: 11/26/2022]
Abstract
Predicting blood flow velocities in patient-specific geometries with Computational Fluid Dynamics (CFD) can provide additional data for diagnosis and treatment planning but the solution can be inaccurate. Therefore, it is crucial to understand the simulation errors and calibrate the numerical model. In-vitro velocity-encoded MRI is a versatile tool to validate CFD. The comparison between CFD and in-vitro MRI velocity data, and the analysis of the simulation error are the objectives of this study. A three-step routine is presented to validate medical CFD data. First, a properly scaled model of the patient-specific geometry is fabricated to achieve high relative resolution in the MRI experiment. Second, the measured flow geometry is matched with the CFD data using one of two algorithms, Coherent Point Drift and Iterative Closest Point. The aligned data sets are then interpolated onto a common grid to enable a point-to-point comparison. Third, the global and local deviations between CFD and MRI velocity data are calculated using different algorithms to reliably estimate the simulation error. The routine is successfully tested with a patient-specific model of a cerebral aneurysm. In conclusion, the methods presented here provide a framework for CFD validation using in-vitro MRI velocity data.
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Affiliation(s)
- Carolin Wüstenhagen
- Institute of Fluid Mechanics, University of Rostock, Justus-von-Liebig-Weg 2, 18059, Rostock, Germany
| | - Kristine John
- Institute of Fluid Mechanics, University of Rostock, Justus-von-Liebig-Weg 2, 18059, Rostock, Germany
| | - Sönke Langner
- Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, Rostock University Medical Center, 18057, Rostock, Germany
| | - Martin Brede
- Institute of Fluid Mechanics, University of Rostock, Justus-von-Liebig-Weg 2, 18059, Rostock, Germany
| | - Sven Grundmann
- Institute of Fluid Mechanics, University of Rostock, Justus-von-Liebig-Weg 2, 18059, Rostock, Germany
| | - Martin Bruschewski
- Institute of Fluid Mechanics, University of Rostock, Justus-von-Liebig-Weg 2, 18059, Rostock, Germany.
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Hohri Y, Itatani K, Yamazaki S, Yaku H. Computerized virtual surgery based on computational fluid dynamics simulation for planning coronary revascularization with aortic root replacement in adult congenital heart disease: a case report. Gen Thorac Cardiovasc Surg 2020; 69:722-726. [PMID: 33130943 PMCID: PMC7981308 DOI: 10.1007/s11748-020-01517-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 10/11/2020] [Indexed: 12/16/2022]
Abstract
A 38-year-old woman presented with exertional dyspnea and chest compression. She had undergone repair of congenital supravalvular aortic stenosis at 8 years of age. Contrast-enhanced computed tomography showed re-stenosis in the ascending aorta, bilateral coronary arterial aneurysm, and a highly thickened left ventricular wall. Release of stenosis was necessary to avoid left ventricular functional deterioration; however, it could cause demand–supply mismatch in coronary flow due to substantial left ventricular hypertrophy. Sufficient statistical evidence was not available in this situation; therefore, computerized virtual surgery based on computational fluid dynamics (CFD) was performed to predict the postoperative hemodynamics. Consequently, root replacement with in situ Carrel patch coronary reconstruction was considered a better option than coronary artery graft bypass in the left-side coronary flow supply. The patient underwent root replacement with in situ Carrel patch coronary reconstruction as planned based on CFD without any complication and was discharged 15 days postoperatively.
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Affiliation(s)
- Yu Hohri
- Department of Cardiovascular Surgery, Cardiovascular Blood Flow Imaging Research Laboratory, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachi Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Keiichi Itatani
- Department of Cardiovascular Surgery, Cardiovascular Blood Flow Imaging Research Laboratory, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachi Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
| | - Sachiko Yamazaki
- Department of Cardiovascular Surgery, Cardiovascular Blood Flow Imaging Research Laboratory, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachi Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Hitoshi Yaku
- Department of Cardiovascular Surgery, Cardiovascular Blood Flow Imaging Research Laboratory, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachi Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
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47
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Computational fluid dynamics simulations of flow distribution and graft designs in apicoaortic bypass. Gen Thorac Cardiovasc Surg 2020; 69:811-818. [PMID: 33125595 DOI: 10.1007/s11748-020-01527-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 10/16/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Apicoaortic bypass has double outlets and its graft design is similar to that of a left ventricular assist device (LVAD). The left ventricular apex to the descending aorta (LV-DsAo) bypass is widely used in apicoaortic bypass. In contrast, the left ventricular apex to the ascending aorta (LV-AsAo) bypass is standard in LVAD surgery. This study aimed to evaluate the graft designs of apicoaortic bypass and their effects on flow distribution and energy loss (EL). METHODS A simulation study using computational fluid dynamics was performed on the geometry and hemodynamics data obtained from a 30-year-old patient who underwent a LV-DsAo bypass. The ratio of the cardiac output (CO) through the ascending aorta (AsAo) and apicoaortic conduit was set at 50:50, 30:70, and 10:90. Regional blood flow (RBF) and EL were calculated for the different distribution ratios. As an alternative to the LV-DsAo bypass, a virtual LV-AsAo bypass surgery was performed, and each parameter was compared with that of the LV-DsAo bypass. RESULTS At a distribution ratio of 50:50, the RBF to the head and EL were 16.4% of the total CO and 62.0 mW in the LV-DsAo bypass, and 32.3% and 81.5 mW in the LV-AsAo bypass, respectively. The RBF to the head decreased with the CO through the AsAo in the LV-DsAo bypass, but it was constant in the LV-AsAo bypass. The EL increased inversely with the CO through the AsAo in both graft designs. CONCLUSION The regional blood flow distribution was different, but the trend of the EL which increased inversely with the CO through the AsAo was similar between the LV-DsAo and LV-AsAo bypasses.
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Emendi M, Sturla F, Ghosh RP, Bianchi M, Piatti F, Pluchinotta FR, Giese D, Lombardi M, Redaelli A, Bluestein D. Patient-Specific Bicuspid Aortic Valve Biomechanics: A Magnetic Resonance Imaging Integrated Fluid-Structure Interaction Approach. Ann Biomed Eng 2020; 49:627-641. [PMID: 32804291 DOI: 10.1007/s10439-020-02571-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 07/14/2020] [Indexed: 12/15/2022]
Abstract
Congenital bicuspid aortic valve (BAV) consists of two fused cusps and represents a major risk factor for calcific valvular stenosis. Herein, a fully coupled fluid-structure interaction (FSI) BAV model was developed from patient-specific magnetic resonance imaging (MRI) and compared against in vivo 4-dimensional flow MRI (4D Flow). FSI simulation compared well with 4D Flow, confirming direction and magnitude of the flow jet impinging onto the aortic wall as well as location and extension of secondary flows and vortices developing at systole: the systolic flow jet originating from an elliptical 1.6 cm2 orifice reached a peak velocity of 252.2 cm/s, 0.6% lower than 4D Flow, progressively impinging on the ascending aorta convexity. The FSI model predicted a peak flow rate of 22.4 L/min, 6.7% higher than 4D Flow, and provided BAV leaflets mechanical and flow-induced shear stresses, not directly attainable from MRI. At systole, the ventricular side of the non-fused leaflet revealed the highest wall shear stress (WSS) average magnitude, up to 14.6 Pa along the free margin, with WSS progressively decreasing towards the belly. During diastole, the aortic side of the fused leaflet exhibited the highest diastolic maximum principal stress, up to 322 kPa within the attachment region. Systematic comparison with ground-truth non-invasive MRI can improve the computational model ability to reproduce native BAV hemodynamics and biomechanical response more realistically, and shed light on their role in BAV patients' risk for developing complications; this approach may further contribute to the validation of advanced FSI simulations designed to assess BAV biomechanics.
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Affiliation(s)
- Monica Emendi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy.,Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Francesco Sturla
- 3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Ram P Ghosh
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Matteo Bianchi
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Filippo Piatti
- 3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Francesca R Pluchinotta
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy.,Multimodality Cardiac Imaging, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy.,Department of Pediatric and Adult Congenital Heart Disease, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | | | - Massimo Lombardi
- Multimodality Cardiac Imaging, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
| | - Alberto Redaelli
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA.
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49
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Franke B, Weese J, Waechter-Stehle I, Brüning J, Kuehne T, Goubergrits L. Towards improving the accuracy of aortic transvalvular pressure gradients: rethinking Bernoulli. Med Biol Eng Comput 2020; 58:1667-1679. [PMID: 32451697 PMCID: PMC7340661 DOI: 10.1007/s11517-020-02186-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 05/01/2020] [Indexed: 10/25/2022]
Abstract
The transvalvular pressure gradient (TPG) is commonly estimated using the Bernoulli equation. However, the method is known to be inaccurate. Therefore, an adjusted Bernoulli model for accurate TPG assessment was developed and evaluated. Numerical simulations were used to calculate TPGCFD in patient-specific geometries of aortic stenosis as ground truth. Geometries, aortic valve areas (AVA), and flow rates were derived from computed tomography scans. Simulations were divided in a training data set (135 cases) and a test data set (36 cases). The training data was used to fit an adjusted Bernoulli model as a function of AVA and flow rate. The model-predicted TPGModel was evaluated using the test data set and also compared against the common Bernoulli equation (TPGB). TPGB and TPGModel both correlated well with TPGCFD (r > 0.94), but significantly overestimated it. The average difference between TPGModel and TPGCFD was much lower: 3.3 mmHg vs. 17.3 mmHg between TPGB and TPGCFD. Also, the standard error of estimate was lower for the adjusted model: SEEModel = 5.3 mmHg vs. SEEB = 22.3 mmHg. The adjusted model's performance was more accurate than that of the conventional Bernoulli equation. The model might help to improve non-invasive assessment of TPG. Graphical abstract Processing pipeline for the definition of an adjusted Bernoulli model for the assessment of transvalvular pressure gradient. Using CT image data, the patient specific geometry of the stenosed AVs were reconstructed. Using this segmentation, the AVA as well as the volume flow rate was calculated and used for model definition. This novel model was compared against classical approaches on a test data set, which was not used for the model definition.
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Affiliation(s)
- Benedikt Franke
- Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité Universitaetsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany.
| | - J Weese
- Philips Research Laboratories, Hamburg, Germany
| | | | - J Brüning
- Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité Universitaetsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - T Kuehne
- Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité Universitaetsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - L Goubergrits
- Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité Universitaetsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany.,Einstein Center Digital Future, Berlin, Germany
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50
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Yoshida S, Toda K, Miyagawa S, Yoshikawa Y, Hata H, Yoshioka D, Kainuma S, Kawamura T, Kawamura A, Nakatani S, Sawa Y. Impact of turbulent blood flow in the aortic root on de novo aortic insufficiency during continuous‐flow left ventricular‐assist device support. Artif Organs 2020; 44:883-891. [DOI: 10.1111/aor.13671] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 01/13/2020] [Accepted: 02/12/2020] [Indexed: 01/18/2023]
Affiliation(s)
| | - Koichi Toda
- Cardiovascular Surgery Osaka University Suita Japan
| | | | | | - Hiroki Hata
- Cardiovascular Surgery Osaka University Suita Japan
| | | | | | | | - Ai Kawamura
- Cardiovascular Surgery Osaka University Suita Japan
| | | | - Yoshiki Sawa
- Cardiovascular Surgery Osaka University Suita Japan
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