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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 2024:10.1007/s13239-024-00723-4. [PMID: 38499933 DOI: 10.1007/s13239-024-00723-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [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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2
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Kalita J, Show S, Biswas N, Datta A. Atherosclerosis risk assessment in human carotid artery with variation in sinus length: a numerical approach. Comput Methods Biomech Biomed Engin 2023:1-15. [PMID: 37950444 DOI: 10.1080/10255842.2023.2275546] [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: 04/10/2023] [Accepted: 10/19/2023] [Indexed: 11/12/2023]
Abstract
The mortality rates due to cardiovascular diseases are on a rise globally. One of the major cardiovascular diseases is stroke which occurs due to atherosclerotic plaques build-up in the carotid artery. The common carotid artery (CCA) bifurcates into the internal carotid artery (ICA) and external carotid artery (ECA). Sinus present at ICA is an ellipsoidal-shaped dilated region acting as a pressure receptor and blood flow regulator. Dimensions of the sinus vary from person to person, affecting the hemodynamics of the carotid artery. The current numerical study manifests a 3D flow analysis by varying the sinus length to investigate its local and global effects on the hemodynamics of the carotid artery using various biomechanical risk analysis parameters of atherosclerosis. User-defined function (UDF) dictates the pulsatile flow velocity profile imposed at the inlet. Near the outer wall (OW) of the sinus, the blood flow velocities are lower and recirculation zones are more. Though the recirculation zones for shorter sinus will be close to the inner wall (IW), interestingly, with an increase in the sinus length, the recirculation zones shift toward the OW with higher strength. These significantly decrease the x-wall shear stress (x-WSS) and time-averaged wall shear stress (TAWSS) values on the OW of the longer sinus. The other risk analysis parameters, like oscillatory shear index (OSI) and relative residence time (RRT), support the described consequences. These results reveal that sinus of increased length is more prone to developing atherosclerotic plaque.
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Affiliation(s)
- Jinmay Kalita
- Department of Mechanical Engineering, NIT Durgapur, Durgapur, India
| | - Subham Show
- Department of Mechanical Engineering, NIT Durgapur, Durgapur, India
| | - Nirmalendu Biswas
- Department of Power Engineering, Jadavpur University, Kolkata, India
| | - Aparesh Datta
- Department of Mechanical Engineering, NIT Durgapur, Durgapur, India
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3
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Johnson S, Dwivedi A, Mirza M, McCarthy R, Gilvarry M. A Review of the Advancements in the in-vitro Modelling of Acute Ischemic Stroke and Its Treatment. FRONTIERS IN MEDICAL TECHNOLOGY 2022; 4:879074. [PMID: 35756535 PMCID: PMC9214215 DOI: 10.3389/fmedt.2022.879074] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/29/2022] [Indexed: 11/13/2022] Open
Abstract
In-vitro neurovascular models of large vessel occlusions (LVOs) causing acute ischemic stroke (AIS) are used extensively for pre-clinical testing of new treatment devices. They enable physicians and engineers to examine device performance and the response of the occlusion to further advance design solutions for current unmet clinical needs. These models also enable physicians to train on basic skills, to try out new devices and new procedural approaches, and for the stroke team to practice workflows together in the comfort of a controlled environment in a non-clinical setting. Removal of the occlusive clot in its entirety is the primary goal of the endovascular treatment of LVOs via mechanical thrombectomy (MT) and the medical treatment via thrombolysis. In MT, recanalization after just one pass is associated with better clinical outcomes than procedures that take multiple passes to achieve the same level of recanalization, commonly known as first pass effect (FPE). To achieve this, physicians and engineers are continually investigating new devices and treatment approaches. To distinguish between treatment devices in the pre-clinical setting, test models must also be optimized and expanded become more nuanced and to represent challenging patient cohorts that could be improved through new technology or better techniques. The aim of this paper is to provide a perspective review of the recent advancements in the in-vitro modeling of stroke and to outline how these models need to advance further in future. This review provides an overview of the various in-vitro models used for the modeling of AIS and compares the advantages and limitations of each. In-vitro models remain an extremely useful tool in the evaluation and design of treatment devices, and great strides have been made to improve replication of physiological conditions. However, further advancement is still required to represent the expanding indications for thrombectomy and thrombolysis, and the generation of new thrombectomy devices, to ensure that smaller treatment effects are captured.
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Affiliation(s)
- Sarah Johnson
- Cerenovus (Johnson & Johnson), Galway Neuro Technology Centre, Galway, Ireland
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4
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Williamson PN, Docherty PD, Yazdi SG, Khanafer A, Kabaliuk N, Jermy M, Geoghegan PH. Review of the Development of Hemodynamic Modeling Techniques to Capture Flow Behavior in Arteries Affected by Aneurysm, Atherosclerosis, and Stenting. J Biomech Eng 2022; 144:1128816. [PMID: 34802061 DOI: 10.1115/1.4053082] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Indexed: 02/05/2023]
Abstract
Cardiovascular diseases (CVDs) are the leading cause of death in the developed world. CVD can include atherosclerosis, aneurysm, dissection, or occlusion of the main arteries. Many CVDs are caused by unhealthy hemodynamics. Some CVDs can be treated with the implantation of stents and stent grafts. Investigations have been carried out to understand the effects of stents and stent grafts have on arteries and the hemodynamic changes post-treatment. Numerous studies on stent hemodynamics have been carried out using computational fluid dynamics (CFD) which has yielded significant insight into the effect of stent mesh design on near-wall blood flow and improving hemodynamics. Particle image velocimetry (PIV) has also been used to capture behavior of fluids that mimic physiological hemodynamics. However, PIV studies have largely been restricted to unstented models or intra-aneurysmal flow rather than peri or distal stent flow behaviors. PIV has been used both as a standalone measurement method and as a comparison to validate the CFD studies. This article reviews the successes and limitations of CFD and PIV-based modeling methods used to investigate the hemodynamic effects of stents. The review includes an overview of physiology and relevant mechanics of arteries as well as consideration of boundary conditions and the working fluids used to simulate blood for each modeling method along with the benefits and limitations introduced.
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Affiliation(s)
- Petra N Williamson
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Paul D Docherty
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Sina G Yazdi
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Adib Khanafer
- Vascular, Endovascular, and Renal Transplant Unit, Christchurch Hospital, Canterbury District Health Board, Riccarton Avenue, Christchurch 8053, New Zealand; Christchurch School of Medicine, University of Otago, Dunedin 9016, New Zealand
| | - Natalia Kabaliuk
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Mark Jermy
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Patrick H Geoghegan
- School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK; Department of Mechanical and Industrial Engineering, University of South Africa, Johannesburg 2006, South Africa
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5
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Wu X, Gürzing S, Schinkel C, Toussaint M, Perinajová R, van Ooij P, Kenjereš S. Hemodynamic Study of a Patient-Specific Intracranial Aneurysm: Comparative Assessment of Tomographic PIV, Stereoscopic PIV, In Vivo MRI and Computational Fluid Dynamics. Cardiovasc Eng Technol 2021; 13:428-442. [PMID: 34750782 PMCID: PMC9197918 DOI: 10.1007/s13239-021-00583-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 10/11/2021] [Indexed: 11/20/2022]
Abstract
Introduction Wall shear stress (WSS) is associated with the growth and rupture of an intracranial aneurysm. To reveal their underlying connections, many image-based computational fluid dynamics (CFD) studies have been conducted. However, the methodological validations using both in vivo medical imaging and in vitro optical flow measurements were rarely accompanied in such studies. Methods In the present study, we performed a comparative assessment on the hemodynamics of a patient-specific intracranial saccular aneurysm using in vivo 4D Flow MRI, in silico CFD, in vitro stereoscopic and tomographic particle imaging velocimetry (Stereo-PIV and Tomo-PIV) techniques. PIV experiments and CFD were conducted under steady state corresponding to the peak systole of 4D Flow MRI. Results The results showed that all modalities provided similar flow features and overall surface distribution of WSS. However, a large variation in the absolute WSS values was found. 4D Flow MRI estimated a 2- to 4-fold lower peak WSS (3.99 Pa) and a 1.6- to 2-fold lower mean WSS (0.94 Pa) than Tomo-PIV, Stereo-PIV, and CFD. Bland-Altman plots of WSS showed that the differences between PIV-/CFD-based WSS and 4D Flow MRI-based WSS increase with higher WSS magnitude. Such proportional trend was absent in the Bland-Altman comparison of velocity where the resolutions of PIV and CFD datasets were matched to 4D Flow MRI. We also found that because of superior resolution in the out-of-plane direction, WSS estimation by Tomo-PIV was higher than Stereo-PIV. Conclusions Our results indicated that the differences in spatial resolution could be the main contributor to the discrepancies between each modality. The findings of this study suggest that with current techniques, care should be taken when using absolute WSS values to perform a quantitative risk analysis of aneurysm rupture. Supplementary Information The online version contains supplementary material available at 10.1007/s13239-021-00583-2.
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Affiliation(s)
- Xiaolin Wu
- 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
| | - Stefanie Gürzing
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands
| | - Christiaan Schinkel
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands
| | - Merel Toussaint
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands
| | - 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
| | - Pim van Ooij
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, 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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Norris NG, Merritt WC, Becker TA. Application of nondestructive mechanical characterization testing for creating in vitro vessel models with material properties similar to human neurovasculature. J Biomed Mater Res A 2021; 110:612-622. [PMID: 34617389 DOI: 10.1002/jbm.a.37314] [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: 04/19/2021] [Revised: 09/15/2021] [Accepted: 09/17/2021] [Indexed: 11/09/2022]
Abstract
Vessel models are a first step in developing endovascular medical devices. However, these models, often made from glass or silicone, do not accurately represent the mechanical properties of human vascular tissue, limiting their use to basic training and proof-of-concept testing. This study outlines methods to quantify human vascular tissue mechanical properties and synthetic biomaterials for creating representative vessel models. Human vascular tissue was assessed and compared to silicone and new UV-cured polymers (VC-A30) using the following eight mechanical tests: compressive, shear, tensile dynamic elastic modulus, Poisson's ratio, hardness, radial force, compliance, and lubricity. Half of these testing methods were nondestructive, allowing for multiple mechanical and histological characterizations of the same human tissue sample. Histological evaluation of the cellular and extracellular matrix of the human vessels verified that the dynamic moduli and Poison's ratio tests were nondestructive. Fluid absorption by VC-A30 showed statistically significant softening of mechanical properties, stabilizing after 4 days in phosphate-buffered saline (PBS). Human vasculature exhibited notably similar results to VC-A30 in five of eight mechanical tests (≤30% difference) versus two of eight for standard silicone (≤38% difference). Results show that VC-A30 provides a new option for 3D-printing translucent in vitro vascular models with anatomically relevant mechanical properties. These new vessel analogs may simulate patient-specific vessel disease states, improve surgical training models, accelerate new endovascular device developments, and ultimately reduce the need for animal models.
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Affiliation(s)
- Nicholas G Norris
- Mechanical Engineering, Northern Arizona University, Flagstaff, Arizona, USA
| | - William C Merritt
- Mechanical Engineering, Northern Arizona University, Flagstaff, Arizona, USA
| | - Timothy A Becker
- Mechanical Engineering, Northern Arizona University, Flagstaff, Arizona, USA
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7
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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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8
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Perinajová R, Juffermans JF, Westenberg JJM, van der Palen RLF, van den Boogaard PJ, Lamb HJ, Kenjereš S. Geometrically induced wall shear stress variability in CFD-MRI coupled simulations of blood flow in the thoracic aortas. Comput Biol Med 2021; 133:104385. [PMID: 33894502 DOI: 10.1016/j.compbiomed.2021.104385] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 04/02/2021] [Accepted: 04/03/2021] [Indexed: 01/16/2023]
Abstract
Aortic aneurysm is associated with aberrant blood flow and wall shear stress (WSS). This can be studied by coupling magnetic resonance imaging (MRI) with computational fluid dynamics (CFD). For patient-specific simulations, extra attention should be given to the variation in segmentation of the MRI data-set and its effect on WSS. We performed CFD simulations of blood flow in the aorta for ten different volunteers and provided corresponding WSS distributions. The aorta of each volunteer was segmented four times. The same inlet and outlet boundary conditions were applied for all segmentation variations of each volunteer. Steady-state CFD simulations were performed with inlet flow based on phase-contrast MRI during peak systole. We show that the commonly used comparison of mean and maximal values of WSS, based on CFD in the different segments of the thoracic aorta, yields good to excellent correlation (0.78-0.95) for rescan and moderate to excellent correlation (0.64-1.00) for intra- and interobserver reproducibility. However, the effect of geometrical variations is higher for the voxel-to-voxel comparison of WSS. With this analysis method, the correlation for different segments of the whole aorta is poor to moderate (0.43-0.66) for rescan and poor to good (0.48-0.73) for intra- and interobserver reproducibility. Therefore, we advise being critical about the CFD results based on the MRI segmentations to avoid possible misinterpretation. While the global values of WSS are similar for different modalities, the variation of results is high when considering the local distributions.
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Affiliation(s)
- Romana Perinajová
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology and J.M. Burgerscentrum Research School for Fluid Mechanics, Delft, the Netherlands.
| | - Joe F Juffermans
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Jos J M Westenberg
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Roel L F van der Palen
- Division of Pediatric Cardiology, Department of Pediatrics, 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 and J.M. Burgerscentrum Research School for Fluid Mechanics, Delft, the Netherlands.
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Williamson PN, Docherty PD, Yazdi SG, Khanafer A, Kabaliuk N, Jermy M. PIV Analysis of Haemodynamics Distal to the Frozen Elephant Trunk Stent Surrogate. Cardiovasc Eng Technol 2021; 12:373-386. [PMID: 33675018 DOI: 10.1007/s13239-021-00521-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 01/13/2021] [Indexed: 11/30/2022]
Abstract
PURPOSE The Frozen Elephant Trunk (FET) stent is a hybrid endovascular device that may be implemented in the event of an aneurysm or aortic dissection of the aortic arch or superior descending aorta. A Type 1B endoleak can lead to intrasaccular flow during systole and has been identified as a known failure of the FET stent graft. The purpose was to develop in-vitro modelling techniques to enable the investigation of the known failure. METHODS A silicone aortic phantom and 3D printed surrogate stent graft were manufactured to investigate the haemodynamics of a Type 1B endoleak. Physiological pulsatile flow dynamics distal to the surrogate stent graft were investigated in-vitro using Particle Image Velocimetry (PIV). RESULTS PIV captured recirculation zones and an endoleak distal to the surrogate stent graft. The endoleak was developed at the peak of systole and sustained until the onset of diastole. The endoleak was asymmetric, indicating a potential variation in the phantom artery wall thickness or stent alignment. Recirculation was identified on the posterior dorsal line during late systole. CONCLUSIONS The identification of the Type 1B endoleak proved that in-vitro modelling can be used to investigate complex compliance changes and wall motions. The recirculation may indicate the potential for long term intimal layer inflammatory issues such as atherosclerosis. These results may aid future remediation techniques or stent design. Further development of the methods used in this experiment may assist with the future testing of stents prior to animal or human trial.
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Affiliation(s)
- Petra N Williamson
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, 8041, New Zealand
| | - Paul D Docherty
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, 8041, New Zealand. .,Institute of Technical Medicine, Furtwangen University, Campus Villingen-Schwenningen, Jakob-Kienzle Strasse 17, 78054, Villingen-Schwenningen, Germany.
| | - Sina G Yazdi
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, 8041, 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, Dunedin, New Zealand
| | - Natalia Kabaliuk
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, 8041, New Zealand
| | - Mark Jermy
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, 8041, New Zealand
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10
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Yazdi SG, Docherty PD, Khanafer A, Jermy M, Kabaliuk N, Geoghegan PH, Williamson P. In-vitro particle image velocimetry assessment of the endovascular haemodynamic features distal of stent-grafts that are associated with development of limb occlusion. J R Soc N Z 2020. [DOI: 10.1080/03036758.2020.1826988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Sina G. Yazdi
- Department of Mechanical Engineering, University of Canterbury, Christchurch, New Zealand
| | - Paul D. Docherty
- Department of Mechanical Engineering, University of Canterbury, Christchurch, New Zealand
- Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
| | - Adib Khanafer
- Department of Surgery, University of Otago, Christchurch, New Zealand
| | - Mark Jermy
- Department of Mechanical Engineering, University of Canterbury, Christchurch, New Zealand
| | - Natalia Kabaliuk
- Department of Mechanical Engineering, University of Canterbury, Christchurch, New Zealand
| | - Patrick H. Geoghegan
- Department of Biomedical Engineering, School of Life & Health Sciences, Aston University, Birmingham, UK
- Department of Mechanical and Industrial Engineering, University of South Africa, Johannesburg, South Africa
| | - Petra Williamson
- Department of Mechanical Engineering, University of Canterbury, Christchurch, New Zealand
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11
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Park JH, Lee SJ. Ultrasound Deep Learning for Wall Segmentation and Near-Wall Blood Flow Measurement. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2020; 67:2022-2032. [PMID: 32746163 DOI: 10.1109/tuffc.2020.2995467] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Studies of medical flow imaging have technical limitations for accurate analysis of blood flow dynamics and vessel wall interaction at arteries. We propose a new deep learning-based boundary detection and compensation (DL-BDC) technique in ultrasound (US) imaging. It can segment vessel boundaries by harnessing the convolutional neural network and wall motion compensation in the analysis of near-wall flow dynamics. The network enables training from real and synthetic US images together. The performance of the technique is validated through synthetic US images and tissue-mimicking phantom experiments. The neural network performs well with high Dice coefficients of over 0.94 and 0.9 for lumens and walls, outperforming previous segmentation techniques. Then, the performance of the wall motion compensation is examined for compliant phantoms. When DL-BDC is applied to flow influenced by wall motion, root-mean-square errors are less than 0.07%. The technique is utilized to analyze flow dynamics and wall interaction with varying elastic moduli of the phantoms. The results show that the flow dynamics and wall shear stress values are consistent with the expected values of the compliant phantoms, and their wall motion behavior is observed with pulse wave propagation. This strategy makes US imaging capable of simultaneous measurement of blood flow and vessel dynamics in human arteries for their accurate interaction analysis. DL-BDC can segment vessel walls fast, accurately, and robustly. It enables to measure the near-wall flow precisely by determining the vessel boundary dynamics. This approach can be beneficial in flow dynamics and wall interaction analyses in various biomedical applications.
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12
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Jeong Y, Yao Y, Yim EKF. Current understanding of intimal hyperplasia and effect of compliance in synthetic small diameter vascular grafts. Biomater Sci 2020; 8:4383-4395. [PMID: 32643723 PMCID: PMC7452756 DOI: 10.1039/d0bm00226g] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Despite much effort, synthetic small diameter vascular grafts still face limited success due to vascular wall thickening known as intimal hyperplasia (IH). Compliance mismatch between graft and native vessels has been proposed to be one of a key mechanical factors of synthetic vascular grafts that could contribute to the formation of IH. While many methods have been developed to determine compliance both in vivo and in vitro, the effects of compliance mismatch still remain uncertain. This review aims to explain the biomechanical factors that are responsible for the formation and development of IH and their relationship with compliance mismatch. Furthermore, this review will address the current methods used to measure compliance both in vitro and in vivo. Lastly, current limitations in understanding the connection between the compliance of vascular grafts and the role it plays in the development and progression of IH will be discussed.
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Affiliation(s)
- YeJin Jeong
- Department of Chemical engineering, University of Waterloo, 200 University Ave W, Waterloo, ON N2L 3G1, Canada.
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Williamson P, Docherty PD, Yazdi SG, Jermy M, Khanafer A, Kabaliuk N, Geoghegan PH. PIV Analysis of Stented Haemodynamics in the Descending Aorta. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:4737-4740. [PMID: 31946920 DOI: 10.1109/embc.2019.8856823] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cardiovascular diseases (CVD) are the leading cause of death in the developed world and aortic aneurysm is a key contributor. Aortic aneurysms typically occur in the thoracic aorta and can extend into the descending aorta. The Frozen Elephant Trunk stent (FET) is one of the leading treatments for the aneurysms extending into the descending aorta. This study focuses on the in-vitro experimentation of a stented descending aorta, investigating the haemodynamics in a compliant phantom. A silicone phantom of the descending aorta was manufactured using a lost core casting method. A PVC stent was manufactured using the same mould core. Particle Image Velocimetry (PIV) was used for pulsatile studies, focusing specifically on the passive fixation at the distal end of the FET. The results showed an apparent expansion in the diastolic period that was identified to be a collapse in the lateral plane. Flow recirculation regions were identified during the collapse. The collapse was attributed to low upstream and high downstream pressures causing a vacuum effect. The findings may imply a potential risk introduced by the FET stent that requires further investigation.
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A Novel Fabrication Method for Compliant Silicone Phantoms of Arterial Geometry for Use in Particle Image Velocimetry of Haemodynamics. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9183811] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Cardiovascular diseases (CVDs) are one of the leading causes of death globally. In-vitro measurement of blood flow in compliant arterial phantoms can provide better insight into haemodynamic states and therapeutic procedures. However, current fabrication techniques are not capable of producing thin-walled compliant phantoms of complex shapes. This study presents a new approach for the fabrication of compliant phantoms suitable for optical measurement. Two 1.5× scaled models of the ascending aorta, including the brachiocephalic artery (BCA), were fabricated from silicone elastomer Sylgard-184. The initial phantom used the existing state of the art lost core manufacturing technique with simple end supports, an acrylonitrile butadiene styrene (ABS) additive manufactured male mould and Ebalta-milled female mould. The second phantom was produced with the same method but used more rigid end supports and ABS male and female moulds. The wall thickness consistency and quality of resulting stereoscopic particle image velocimetry (SPIV) were used to verify the fidelity of the phantom for optical measurement and investigation of physiological flow fields. However, the initial phantom had a rough surface that obscured SPIV analysis and had a variable wall thickness (range = 0.815 mm). The second phantom provided clear particle images and had a less variable wall thickness (range = 0.317 mm). The manufacturing method developed is suitable for fast and cost-effective fabrication of different compliant arterial phantom geometries.
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FROLOV SV, SINDEEV SV, LIEPSCH D, BALASSO A, ARNOLD P, KIRSCHKE JS, PROTHMANN S, POTLOV AYU. NEWTONIAN AND NON-NEWTONIAN BLOOD FLOW AT A 90∘-BIFURCATION OF THE CEREBRAL ARTERY: A COMPARATIVE STUDY OF FLUID VISCOSITY MODELS. J MECH MED BIOL 2018. [DOI: 10.1142/s0219519418500434] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The majority of numerical simulations assumes blood as a Newtonian fluid due to an underestimation of the effect of non-Newtonian blood behavior on hemodynamics in the cerebral arteries. In the present study, we evaluated the effect of non-Newtonian blood properties on hemodynamics in the idealized 90[Formula: see text]-bifurcation model, using Newtonian and non-Newtonian fluids and different flow rate ratios between the parent artery and its branch. The proposed Local viscosity model was employed for high-precision representation of blood viscosity changes. The highest velocity differences were observed at zones with slow recirculating flow. During the systolic peak the average difference was 17–22%, whereas at the end of diastole the difference increased to 27–60% depending on the flow rate ratio. The main changes in the viscosity distribution were observed distal to the flow separation point, where the non-Newtonian fluid model produced 2.5 times higher viscosity. A presence of such high viscosity region substantially affected the size of the flow recirculation zone. The observed differences showed that non-Newtonian blood behavior had a significant effect on hemodynamic parameters and should be considered in the future studies of blood flow in cerebral arteries.
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Affiliation(s)
- S. V. FROLOV
- Biomedical Engineering Department, Tambov State Technical University, Sovetskaya Street, 106, Tambov, Russia
| | - S. V. SINDEEV
- Biomedical Engineering Department, Tambov State Technical University, Sovetskaya Street, 106, Tambov, Russia
| | - D. LIEPSCH
- Department of Building Services Engineering, Paper and Packaging Technology and Print and Media Technology, Munich University of Applied Sciences, Lothstrasse, 34, Munich, Germany
| | - A. BALASSO
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-University, Luisenstrasse Strasse, 37, Munich, Germany
| | - P. ARNOLD
- Department of Diagnostic and Interventional Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Ismaninger Strasse, 22, Munich, Germany
| | - J. S. KIRSCHKE
- Department of Diagnostic and Interventional Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Ismaninger Strasse, 22, Munich, Germany
| | - S. PROTHMANN
- Institute of Diagnostic and Interventional Neuroradiology, HELIOS Klinikum Munchen West Steinerweg, 5, Munich, Germany
| | - A. YU. POTLOV
- Biomedical Engineering Department, Tambov State Technical University, Sovetskaya Street, 106, Tambov, Russia
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Yazdi SG, Geoghegan PH, Docherty PD, Jermy M, Khanafer A. A Review of Arterial Phantom Fabrication Methods for Flow Measurement Using PIV Techniques. Ann Biomed Eng 2018; 46:1697-1721. [DOI: 10.1007/s10439-018-2085-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 06/25/2018] [Indexed: 12/21/2022]
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17
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Docherty P, Geoghegan P, Huetter L, Jermy M, Sellier M. Regressive cross-correlation of pressure signals in the region of stenosis: Insights from particle image velocimetry experimentation. Biomed Signal Process Control 2017. [DOI: 10.1016/j.bspc.2016.09.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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