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Minderhoud SCS, Arrouby A, van den Hoven AT, Bons LR, Chelu RG, Kardys I, Rizopoulos D, Korteland SA, van den Bosch AE, Budde RPJ, Roos-Hesselink JW, Wentzel JJ, Hirsch A. Regional Aortic Wall Shear Stress Increases over Time in Patients with a Bicuspid Aortic Valve. J Cardiovasc Magn Reson 2024:101070. [PMID: 39096969 DOI: 10.1016/j.jocmr.2024.101070] [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: 11/20/2023] [Revised: 06/23/2024] [Accepted: 07/24/2024] [Indexed: 08/05/2024] Open
Abstract
BACKGROUND Aortic wall shear stress (WSS) is a known predictor of ascending aortic growth in patients with a bicuspid aortic valve (BAV). The aim of this study was to study regional WSS and changes over time in BAV patients. METHODS BAV patients and age-matched healthy controls underwent 4D flow CMR. Regional, peak systolic ascending aortic WSS, aortic valve function, aortic stiffness measures and aortic dimensions were assessed. In BAV patients, 4D flow CMR was repeated after three years follow-up and both at baseline and follow-up computed tomography angiography (CTA) was acquired. Aortic growth (volume increase of ≥5%) was measured on CTA. Regional WSS differences within patients' aorta and WSS changes over time were analysed using linear mixed-effect models and were associated with clinical parameters. RESULTS Thirty BAV patients (aged 34 years [IQR 25-41]) were included in the follow-up analysis. Additionally, another 16 BAV patients and 32 healthy controls (aged 33 years [IQR 28-48]) were included for other regional analyses. Magnitude, axial, and circumferential WSS increased over time (all p<0.001) irrespective of aortic growth. The percentage of regions exposed to a magnitude WSS >95th percentile of healthy controls increased from 21% (baseline 506/2400 regions) to 31% (follow-up 734/2400 regions) (p<0.001). WSS angle, a measure of helicity near the aortic wall, decreased during follow-up. Magnitude WSS changes over time were associated with systolic blood pressure, peak aortic valve velocity, aortic valve regurgitation fraction, aortic stiffness indexes, and normalized flow displacement (all p<0.05). CONCLUSIONS An increase of regional WSS over time was observed in BAV patients, irrespective of aortic growth. The increasing WSSs comprising a larger area of the aorta warrants further research to investigate the possible predictive value for aortic dissection.
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Affiliation(s)
- Savine C S Minderhoud
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands; Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands.
| | - Aïmane Arrouby
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands.
| | - Allard T van den Hoven
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands.
| | - Lidia R Bons
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands; Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands.
| | - Raluca G Chelu
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands; Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands.
| | - Isabella Kardys
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands.
| | - Dimitris Rizopoulos
- Department of Biostatistics, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands.
| | - Suze-Anne Korteland
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands.
| | - Annemien E van den Bosch
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands.
| | - Ricardo P J Budde
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands; Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands.
| | - Jolien W Roos-Hesselink
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands.
| | - Jolanda J Wentzel
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands.
| | - Alexander Hirsch
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands.
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Futami K, Misaki K, Uno T, Nambu I, Kamide T, Nakada M. Characterization of Maximum Wall Shear Stress Points in Unruptured Cerebral Aneurysms Using Four-dimensional Flow Magnetic Resonance Imaging. Clin Neuroradiol 2024:10.1007/s00062-024-01436-w. [PMID: 39017672 DOI: 10.1007/s00062-024-01436-w] [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: 01/27/2024] [Accepted: 06/21/2024] [Indexed: 07/18/2024]
Abstract
BACKGROUND Maximum wall shear stress (maxWSS) points of unruptured cerebral aneurysms (UCAs) may cause wall remodeling leading to rupture. We characterized maxWSS points and their inherent intra-aneurysmal flow structures in a sizable cohort of saccular UCAs using four-dimensional (4D) flow magnetic resonance imaging (MRI). METHODS After contrast administration, 50 saccular UCAs were subjected to 4D flow MRI using a 1.5 T MRI scanner. Post-processing of obtained data was performed using commercially available software. The maxWSS points and maxWSS values were evaluated. The maxWSS values were statistically compared between aneurysm groups. RESULTS The maxWSS point was located on the aneurysm apex in 9 (18.0%), body in 2 (4.0%), and neck in 39 (78.0%) UCAs. The inherent intra-aneurysmal flow structure of the maxWSS point was an inflow zone in 34 (68.0%) UCAs, an inflow jet in 8 (16.0%), and an impingement zone in 8 (16.0%). The maxWSS point on the neck had significantly higher maxWSS values than those points on the other wall areas (P = 0.008). The maxWSS values of the maxWSS points on the apex and on the impingement zone were not significantly different compared with those of the other maxWSS points. CONCLUSION The maxWSS points existed preferentially on the aneurysmal neck adjacent to the inflow zone with higher maxWSS values. The maxWSS points existed occasionally on the aneurysmal apex adjacent to the impingement zone. 4D flow MRI may be helpful to discriminate saccular UCAs with higher-risk maxWSS points that can cause wall remodeling leading to rupture.
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Affiliation(s)
- Kazuya Futami
- Department of Neurosurgery, Hokuriku Central Hospital of Japan Mutual Aid Association of Public School Teachers, 123 Nodera, Oyabe, 932-8503, Toyama, Japan.
| | - Kouichi Misaki
- Department of Neurosurgery, Kanazawa University School of Medicine, Kanazawa, Japan
| | - Takehiro Uno
- Department of Neurosurgery, Kanazawa University School of Medicine, Kanazawa, Japan
| | - Iku Nambu
- Department of Neurosurgery, Kanazawa University School of Medicine, Kanazawa, Japan
| | - Tomoya Kamide
- Department of Neurosurgery, Kanazawa University School of Medicine, Kanazawa, Japan
| | - Mitsutoshi Nakada
- Department of Neurosurgery, Kanazawa University School of Medicine, Kanazawa, Japan
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El Sayed R, Park CC, Shah Z, Nahab FB, Haussen DC, Allen JW, Oshinski JN. Assessment of Complex Flow Patterns in Patients With Carotid Webs, Patients With Carotid Atherosclerosis, and Healthy Subjects Using 4D Flow MRI. J Magn Reson Imaging 2024; 59:2001-2010. [PMID: 37706274 PMCID: PMC10937327 DOI: 10.1002/jmri.29013] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 09/15/2023] Open
Abstract
BACKGROUND Carotid webs (CaWs) are fibromuscular projections in the internal carotid artery (ICA) that cause mild luminal narrowing (<50%), but may be causative in up to one-third of seemingly cryptogenic strokes. Understanding hemodynamic alterations caused by CaWs is imperative to assessing stroke risk. Time-Average Wall Shear Stress (TAWSS) and Oscillatory Shear Index (OSI) are hemodynamic parameters linked to vascular dysfunction and thrombosis. PURPOSE To test the hypothesis: "CaWs are associated with lower TAWSS and higher OSI than mild atherosclerosis or healthy carotid bifurcation." STUDY TYPE Prospective study. POPULATION A total of 35 subjects (N = 14 bifurcations with CaW, 11F, age: 49 ± 10, 10 mild atherosclerosis 6F, age: 72 ± 9, 11 healthy 9F, age: 42 ± 13). FIELD STRENGTH/SEQUENCE 4D flow/STAR-MATCH/3D TOF/3T MRI, CTA. ASSESSMENT 4D Flow velocity data were analyzed in two ways: 1) 3D ROI in the ICA bulbar segment (complex flow patterns are expected) was used to quantify the regions with low TAWSS and high OSI. 2) 2D planes were placed perpendicular to the centerline of the carotid bifurcation for detailed analysis of TAWSS and OSI. STATISTICAL TESTS Independent-samples Kruskal-Wallis-H test with 0.05 used for statistical significance. RESULTS The percent surface area where low TAWSS was present in the ICA bulb was 12.3 ± 8.0% (95% CI: 7.6-16.9) in CaW subjects, 1.6 ± 1.9% (95% CI: 0.2-2.9) in atherosclerosis, and 8.5 ± 7.7% (95% CI: 3.6-13.4) in healthy subjects, all differences were statistically significant (ƞ2 = 0.3 [95% CI: 0.05-0.5], P-value CaW vs. healthy = 0.2). OSI had similar values in the CCA between groups (ƞ2 = 0.07 [95% CI: 0.0-0.2], P-value = 0.5), but OSI was significantly higher downstream of the bifurcation in CaW subjects compared to atherosclerosis and normal subjects. OSI returned to similar values between groups 1.5 diameters distal to the bifurcation (ƞ2 = 0.03 [95% CI: 0.0-0.2], P-value = 0.7). CONCLUSION Lower TAWSS and higher OSI are present in the ICA bulb in patients with CaW when compared to patients with atherosclerotic or healthy subjects. EVIDENCE LEVEL 2 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Retta El Sayed
- Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Georgia, USA
- Department of Radiology & Imaging Sciences, Emory University, Atlanta, Georgia, USA
| | - Charlie C. Park
- Department of Radiology & Imaging Sciences, Emory University, Atlanta, Georgia, USA
| | - Zahraw Shah
- Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Georgia, USA
| | - Fadi B. Nahab
- Department of Neurology, Emory University, Atlanta, Georgia, USA
| | - Diogo C. Haussen
- Department of Neurology, Emory University, Atlanta, Georgia, USA
| | - Jason W. Allen
- Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Georgia, USA
- Department of Radiology & Imaging Sciences, Emory University, Atlanta, Georgia, USA
- Department of Neurology, Emory University, Atlanta, Georgia, USA
| | - John N. Oshinski
- Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Georgia, USA
- Department of Radiology & Imaging Sciences, Emory University, Atlanta, Georgia, USA
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El Sayed R, Lucas CJ, Cebull HL, Nahab FB, Haussen DC, Allen JW, Oshinski JN. Subjects with carotid webs demonstrate pro-thrombotic hemodynamics compared to subjects with carotid atherosclerosis. Sci Rep 2024; 14:10092. [PMID: 38698141 PMCID: PMC11066020 DOI: 10.1038/s41598-024-60666-7] [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: 01/23/2024] [Accepted: 04/25/2024] [Indexed: 05/05/2024] Open
Abstract
Carotid artery webs (CaW) are non-atherosclerotic projections into the vascular lumen and have been linked to up to one-third of cryptogenic strokes in younger patients. Determining how CaW affects local hemodynamics is essential for understanding clot formation and stroke risk. Computational fluid dynamics simulations were used to investigate patient-specific hemodynamics in carotid artery bifurcations with CaW, bifurcations with atherosclerotic lesions having a similar degree of lumen narrowing, and with healthy carotid bifurcations. Simulations were conducted using segmented computed tomography angiography geometries with inlet boundary conditions extracted from 2D phase contrast MRI scans. The study included carotid bifurcations with CaW (n = 13), mild atherosclerosis (n = 7), and healthy bifurcation geometries (n = 6). Hemodynamic parameters associated with vascular dysfunction and clot formation, including shear rate, oscillatory shear index (OSI), low velocity, and flow stasis were calculated and compared between the subject groups. Patients with CaW had significantly larger regions containing low shear rate, high OSI, low velocity, and flow stasis in comparison to subjects with mild atherosclerosis or normal bifurcations. These abnormal hemodynamic metrics in patients with CaW are associated with clot formation and vascular dysfunction and suggest that hemodynamic assessment may be a tool to assess stroke risk in these patients.
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Affiliation(s)
- Retta El Sayed
- Department of Biomedical Engineering, Georgia Institute of Technology, Emory University, 1364 Clifton Rd, Atlanta, GA, 30322, USA
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - Carissa J Lucas
- Department of Biomedical Engineering, Georgia Institute of Technology, Emory University, 1364 Clifton Rd, Atlanta, GA, 30322, USA
| | - Hannah L Cebull
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - Fadi B Nahab
- Department of Neurology, Emory University, Atlanta, GA, USA
| | | | - Jason W Allen
- Department of Radiology and Imaging Sciences, Indiana University, Indianapolis, IN, USA
| | - John N Oshinski
- Department of Biomedical Engineering, Georgia Institute of Technology, Emory University, 1364 Clifton Rd, Atlanta, GA, 30322, USA.
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA.
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Bao J, Gan X, Feng W, Li Y, Qiu Y, Zhou M, Guo J, He L. Abnormal flow pattern of low wall shear stress and high oscillatory shear index in spontaneous vertebral artery dissection with vertebral artery hypoplasia. Front Neurosci 2023; 17:1179963. [PMID: 37389359 PMCID: PMC10303804 DOI: 10.3389/fnins.2023.1179963] [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: 03/05/2023] [Accepted: 05/26/2023] [Indexed: 07/01/2023] Open
Abstract
Introduction Spontaneous vertebral artery dissection (sVAD) might tend to develop in vertebral artery hypoplasia (VAH) with hemodynamic dysfunction and it is crucial to assess hemodynamics in sVAD with VAH to investigate this hypothesis. This retrospective study aimed to quantify hemodynamic parameters in patients with sVAD with VAH. Methods Patients who had suffered ischemic stroke due to an sVAD of VAH were enrolled in this retrospective study. The geometries of 14 patients (28 vessels) were reconstructed using Mimics and Geomagic Studio software from CT angiography (CTA). ANSYS ICEM and ANSYS FLUENT were utilized for mesh generation, set boundary conditions, solve governing equations, and perform numerical simulations. Slices were obtained at the upstream area, dissection or midstream area and downstream area of each VA. The blood flow patterns were visualized through instantaneous streamline and pressure at peak systole and late diastole. The hemodynamic parameters included pressure, velocity, time-averaged blood flow, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), endothelial cell action potential (ECAP), relative residence time (RRT) and time-averaged nitric oxide production rate (TARNO). Results Significant focal increased velocity was present in the dissection area of steno-occlusive sVAD with VAH compared to other nondissected areas (0.910 m/s vs. 0.449 vs. 0.566, p < 0.001), while focal slow flow velocity was observed in the dissection area of aneurysmal dilatative sVAD with VAH according to velocity streamlines. Steno-occlusive sVAD with VAH arteries had a lower time-averaged blood flow (0.499 cm3/s vs. 2.268, p < 0.001), lower TAWSS (1.115 Pa vs. 2.437, p = 0.001), higher OSI (0.248 vs. 0.173, p = 0.006), higher ECAP (0.328 Pa-1 vs. 0.094, p = 0.002), higher RRT (3.519 Pa-1 vs. 1.044, p = 0.001) and deceased TARNO (104.014 nM/s vs. 158.195, p < 0.001) than the contralateral VAs. Conclusion Steno-occlusive sVAD with VAH patients had abnormal blood flow patterns of focal increased velocity, low time-averaged blood flow, low TAWSS, high OSI, high ECAP, high RRT and decreased TARNO. These results provide a good basis for further investigation of sVAD hemodynamics and support the applicability of the CFD method in testing the hemodynamic hypothesis of sVAD. More detailed hemodynamic conditions with different stages of sVAD are warranted in the future.
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Affiliation(s)
- Jiajia Bao
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, China
| | - Xinling Gan
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, China
| | - Wentao Feng
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University) Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Yanbo Li
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, China
| | - Yue Qiu
- Department of Applied Mechanics, Sichuan University, Chengdu, China
| | - Muke Zhou
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, China
| | - Jian Guo
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, China
| | - Li He
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, China
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Zhu Y, Xu XY, Rosendahl U, Pepper J, Mirsadraee S. Advanced risk prediction for aortic dissection patients using imaging-based computational flow analysis. Clin Radiol 2023; 78:e155-e165. [PMID: 36610929 DOI: 10.1016/j.crad.2022.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 11/28/2022] [Accepted: 12/02/2022] [Indexed: 12/24/2022]
Abstract
Patients with either a repaired or medically managed aortic dissection have varying degrees of risk of developing late complications. High-risk patients would benefit from earlier intervention to improve their long-term survival. Currently serial imaging is used for risk stratification, which is not always reliable. On the other hand, understanding aortic haemodynamics within a dissection is essential to fully evaluate the disease and predict how it may progress. In recent decades, computational fluid dynamics (CFD) has been extensively applied to simulate complex haemodynamics within aortic diseases, and more recently, four-dimensional (4D)-flow magnetic resonance imaging (MRI) techniques have been developed for in vivo haemodynamic measurement. This paper presents a comprehensive review on the application of image-based CFD simulations and 4D-flow MRI analysis for risk prediction in aortic dissection. The key steps involved in patient-specific CFD analyses are demonstrated. Finally, we propose a workflow incorporating computational modelling for personalised assessment to aid in risk stratification and treatment decision-making.
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Affiliation(s)
- Y Zhu
- Department of Chemical Engineering, Imperial College London, London, UK
| | - X Y Xu
- Department of Chemical Engineering, Imperial College London, London, UK
| | - U Rosendahl
- Department of Cardiac Surgery, Royal Brompton and Harefield Hospitals, London, UK; National Heart and Lung Institute, Imperial College London, London, UK
| | - J Pepper
- Department of Cardiac Surgery, Royal Brompton and Harefield Hospitals, London, UK; National Heart and Lung Institute, Imperial College London, London, UK
| | - S Mirsadraee
- National Heart and Lung Institute, Imperial College London, London, UK; Department of Radiology, Royal Brompton and Harefield Hospitals, London, UK.
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Hurd ER, Iffrig E, Jiang D, Oshinski JN, Timmins LH. Flow-based method demonstrates improved accuracy for calculating wall shear stress in arterial flows from 4D flow MRI data. J Biomech 2023; 146:111413. [PMID: 36535100 PMCID: PMC9845191 DOI: 10.1016/j.jbiomech.2022.111413] [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: 06/15/2022] [Revised: 11/30/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022]
Abstract
Four-dimensional flow magnetic resonance imaging (i.e., 4D flow MRI) has become a valuable tool for the in vivo assessment of blood flow within large vessels and cardiac chambers. As wall shear stress (WSS) has been correlated with the development and progression of cardiovascular disease, focus has been directed at developing techniques to quantify WSS directly from 4D flow MRI data. The goal of this study was to compare the accuracy of two such techniques - termed the velocity and flow-based methods - in the setting of simplified and complex flow scenarios. Synthetic MR data were created from exact solutions to the Navier-Stokes equations for the steady and pulsatile flow of an incompressible, Newtonian fluid through a rigid cylinder. In addition, synthetic MR data were created from the predicted velocity fields derived from a fluid-structure interaction (FSI) model of pulsatile flow through a thick-walled, multi-layered model of the carotid bifurcation. Compared to the analytical solutions for steady and pulsatile flow, the flow-based method demonstrated greater accuracy than the velocity-based method in calculating WSS across all changes in fluid velocity/flow rate, tube radius, and image signal-to-noise (p < 0.001). Furthermore, the velocity-based method was more sensitive to boundary segmentation than the flow-based method. When compared to results from the FSI model, the flow-based method demonstrated greater accuracy than the velocity-based method with average differences in time-averaged WSS of 0.31 ± 1.03 Pa and 0.45 ± 1.03 Pa, respectively (p <0.005). These results have implications on the utility, accuracy, and clinical translational of methods to determine WSS from 4D flow MRI.
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Affiliation(s)
- Elliott R Hurd
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | - Elizabeth Iffrig
- Division of Allergy, Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
| | - David Jiang
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | - John N Oshinski
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA; Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Lucas H Timmins
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT 84112, USA.
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8
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Shen R, Tong X, Li D, Ning Z, Han H, Han Y, Yang D, Du C, Wang T, Cao J, Xu Y, Huo R, Qiao H, Zhao X. Slice-based and time-specific hemodynamic measurements discriminate carotid artery vulnerable atherosclerotic plaques. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 225:107050. [PMID: 35985150 DOI: 10.1016/j.cmpb.2022.107050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/28/2022] [Accepted: 07/28/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND OBJECTIVE Hemodynamic patterns play key roles in progression of carotid vulnerable plaques. However, most of previous studies utilized maximum or averaged value of hemodynamic measurements which is not an ideal representative of hemodynamic patterns. This study aimed to investigate the association of slice-based and time-specific hemodynamic measurements with carotid vulnerable plaque using magnetic resonance (MR) vessel wall imaging and histology. METHODS Thirty-two patients (mean age: 63.9±8.1 years; 25 males) with carotid atherosclerotic stenosis (≥50% stenosis) referred to carotid endarterectomy were recruited and underwent MR vessel wall imaging. Carotid plaque burden was evaluated on MR images and vulnerable plaque features including calcification, lipid-rich necrotic core, and intra-plaque hemorrhage (IPH) were identified by histology. The slice-based and time-specific hemodynamic measurements were extracted from computational fluid dynamics simulation of 3D carotid arterial model. Correlation coefficients between hemodynamic measurements and carotid plaque features were calculated and the logistic regressions with generalized estimating equation (GEE) were conducted. The value in discriminating carotid vulnerable plaque features was determined by receiver-operating-characteristic analysis. RESULTS Of 102 MR-histology matched slices from 32 patients, time-averaged wall shear stress (TAWSS) (r=0.263, p=0.008), oscillatory shear index (OSI) (r=-0.374, p<0.001), and peakWSS (r=0.232, p=0.019) were significantly associated with carotid IPH. The logistic regression with GEE revealed that peakWSS (OR, 1.206; 95% CI, 1.026-1.418; p, 0.023) and TAWSS (OR, 0.364, 95% CI, 0.138-0.959; p, 0.041) were significantly associated with presence of IPH after adjusting for age and BMI. In discriminating carotid IPH, the AUC of TAWSS, OSI, combined TAWSS with maximum wall thickness (MWT) and combined OSI with MWT was 0.656, 0.722, 0.761, and 0.764, respectively. CONCLUSIONS Slice-based and time-specific hemodynamic characteristics could effectively discriminate carotid IPH. Combination of hemodynamic measurements with carotid plaque burden might be a stronger indicator for carotid vulnerable plaque features than each measurement alone.
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Affiliation(s)
- Rui Shen
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Xinyu Tong
- Department of Biomedical Engineering, School of Life and Science, Beijing Institute of Technology, Beijing, China
| | - Dongye Li
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Zihan Ning
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Hualu Han
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Yongjun Han
- Department of Radiology, Aerospace Center Hospital, Beijing, China
| | - Dandan Yang
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Chenlin Du
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Tao Wang
- Department of Neurosurgery, Peking University Third Hospital, Beijing, China
| | - Jingli Cao
- China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yilan Xu
- Department of Radiology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China
| | - Ran Huo
- Department of Radiology, Peking University Third Hospital, Beijing, China
| | - Huiyu Qiao
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China.
| | - Xihai Zhao
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China.
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9
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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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10
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Futami K, Misaki K, Uno T, Nambu I, Tsutsui T, Kamide T, Nakada M. Minimum wall shear stress points and their underlying intra-aneurysmal flow structures of unruptured cerebral aneurysms on 4D flow MRI. J Neuroradiol 2022; 50:302-308. [PMID: 36084742 DOI: 10.1016/j.neurad.2022.09.001] [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: 07/18/2022] [Revised: 09/04/2022] [Accepted: 09/05/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND AND PURPOSE Minimum wall shear stress (Min-WSS) points may be associated with wall instability of unruptured cerebral aneurysms. We aimed to investigate the relationship between the locations of Min-WSS points and their underlying intra-aneurysmal flow structure patterns in unruptured cerebral aneurysms using four-dimensional (4D) flow magnetic resonance imaging (MRI). MATERIALS AND METHODS Min-WSS points and the intra-aneurysmal flow structure patterns were identified in 50 unruptured aneurysms by 4D flow MRI. RESULTS The Min-WSS points were located around a vortex core tip in 31 (62.0%) aneurysms and on an intra-bleb vortex center in 7 (14.0%). Sixteen (32.0%) aneurysms had the Min-WSS points on the aneurysmal apex, and in 24 (48.0%) were on the neck. The Min-WSS values of aneurysms with the Min-WSS points on an intra-bleb flow were significantly lower than those of the other groups (P = 0.030). Aneurysms with the Min-WSS points on the neck had significantly higher Min-WSS values than the other aneurysms (P = 0.008). CONCLUSIONS The location of the Min-WSS point was corresponding to the vortex core or center in 76% of all aneurysms. The underlying intra-aneurysmal flow structure and location of the Min-WSS point affect the Min-WSS value. Further studies are needed to characterize Min-WSS points to identify aneurysms with a higher risk of wall instability.
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Affiliation(s)
- Kazuya Futami
- Department of Neurosurgery, Hokuriku Central Hospital, 123 Nodera, Oyabe, 932-8503 Toyama, Japan.
| | - Kouichi Misaki
- Department of Neurosurgery, Graduate School of Medicine, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641 Ishikawa, Japan.
| | - Takehiro Uno
- Department of Neurosurgery, Graduate School of Medicine, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641 Ishikawa, Japan.
| | - Iku Nambu
- Department of Neurosurgery, Graduate School of Medicine, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641 Ishikawa, Japan.
| | - Taishi Tsutsui
- Department of Neurosurgery, Graduate School of Medicine, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641 Ishikawa, Japan.
| | - Tomoya Kamide
- Department of Neurosurgery, Graduate School of Medicine, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641 Ishikawa, Japan.
| | - Mitsutoshi Nakada
- Department of Neurosurgery, Graduate School of Medicine, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641 Ishikawa, Japan.
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11
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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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12
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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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13
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Hoeijmakers MJMM, Huberts W, Rutten MCM, van de Vosse FN. The impact of shape uncertainty on aortic-valve pressure-drop computations. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3518. [PMID: 34350705 PMCID: PMC9286381 DOI: 10.1002/cnm.3518] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 05/17/2021] [Accepted: 07/04/2021] [Indexed: 06/13/2023]
Abstract
Patient-specific image-based computational fluid dynamics (CFD) is widely adopted in the cardiovascular research community to study hemodynamics, and will become increasingly important for personalized medicine. However, segmentation of the flow domain is not exact and geometric uncertainty can be expected which propagates through the computational model, leading to uncertainty in model output. Seventy-four aortic-valves were segmented from computed tomography images at peak systole. Statistical shape modeling was used to obtain an approximate parameterization of the original segmentations. This parameterization was used to train a meta-model that related the first five shape mode coefficients and flowrate to the CFD-computed transvalvular pressure-drop. Consequently, shape uncertainty in the order of 0.5 and 1.0 mm was emulated by introducing uncertainty in the shape mode coefficients. A global variance-based sensitivity analysis was performed to quantify output uncertainty and to determine relative importance of the shape modes. The first shape mode captured the opening/closing behavior of the valve and uncertainty in this mode coefficient accounted for more than 90% of the output variance. However, sensitivity to shape uncertainty is patient-specific, and the relative importance of the fourth shape mode coefficient tended to increase with increases in valvular area. These results show that geometric uncertainty in the order of image voxel size may lead to substantial uncertainty in CFD-computed transvalvular pressure-drops. Moreover, this illustrates that it is essential to assess the impact of geometric uncertainty on model output, and that this should be thoroughly quantified for applications that wish to use image-based CFD models.
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Affiliation(s)
- M. J. M. M. Hoeijmakers
- Department of Biomedical EngineeringEindhoven University of TechnologyEindhovenThe Netherlands
- AnsysUtrechtThe Netherlands
| | - W. Huberts
- Department of Biomedical EngineeringEindhoven University of TechnologyEindhovenThe Netherlands
- Department of Biomedical Engineering, School for Cardiovsacular DiseasesMaastricht UniversityMaastrichtThe Netherlands
| | - M. C. M. Rutten
- Department of Biomedical EngineeringEindhoven University of TechnologyEindhovenThe Netherlands
| | - F. N. van de Vosse
- Department of Biomedical EngineeringEindhoven University of TechnologyEindhovenThe Netherlands
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14
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Annio G, Torii R, Ducci A, Muthurangu V, Tsang V, Burriesci G. Experimental Validation of Enhanced Magnetic Resonance Imaging (EMRI) Using Particle Image Velocimetry (PIV). Ann Biomed Eng 2021; 49:3481-3493. [PMID: 34181130 DOI: 10.1007/s10439-021-02811-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 06/07/2021] [Indexed: 12/27/2022]
Abstract
Flow-sensitive four-dimensional Cardiovascular Magnetic Resonance Imaging (4D Flow CMR) has increasingly been utilised to characterise patients' blood flow, in association with patiens' state of health and disease, even though spatial and temporal resolutions still constitute a limit. Computational fluid dynamics (CFD) is a powerful tool that could expand these information and, if integrated with experimentally-obtained velocity fields, would enable to derive a large variety of the flow descriptors of interest. However, the accuracy of the flow parameters is highly influenced by the quality of the input data such as the anatomical model and boundary conditions typically derived from medical images including 4D Flow CMR. We previously proposed a novel approach in which 4D Flow CMR and CFD velocity fields are integrated to obtain an Enhanced 4D Flow CMR (EMRI), allowing to overcome the spatial-resolution limitation of 4D Flow CMR, and enable an accurate quantification of flow. In this paper, the proposed approach is validated in a U bend channel, an idealised model of the human aortic arch. The flow patterns were studied with 4D Flow CMR, CFD and EMRI, and compared with high resolution 2D PIV experiments obtained in pulsatile conditions. The main strengths and limitations of 4D Flow CMR and CFD were illustrated by exploiting the accuracy of PIV by comparing against PIV velocity fields. EMRI flow patterns showed a better qualitative and quantitative agreement with PIV results than the other techniques. EMRI enables to overcome the experimental limitations of MRI-based velocity measurements and the modelling simplifications of CFD, allowing an accurate prediction of complex flow patterns observed experimentally, while satisfying mass and momentum balance equations.
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Affiliation(s)
- Giacomo Annio
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK.
| | - Ryo Torii
- Department of Mechanical Engineering, University College London, London, UK.
| | - Andrea Ducci
- Department of Mechanical Engineering, University College London, London, UK
| | - Vivek Muthurangu
- Centre for Cardiovascular Imaging and Physics, University College London, London, UK
| | - Victor Tsang
- Cardiothoracic Surgery Unit, Great Ormond Street Hospital, London, UK
| | - Gaetano Burriesci
- Department of Mechanical Engineering, University College London, London, UK.
- Ri.MED Foundation, Palermo, Italy.
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15
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Ngo MT, Lee UY, Ha H, Jin N, Chung GH, Kwak YG, Jung J, Kwak HS. Comparison of Hemodynamic Visualization in Cerebral Arteries: Can Magnetic Resonance Imaging Replace Computational Fluid Dynamics? J Pers Med 2021; 11:jpm11040253. [PMID: 33808514 PMCID: PMC8066205 DOI: 10.3390/jpm11040253] [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: 03/03/2021] [Revised: 03/23/2021] [Accepted: 03/27/2021] [Indexed: 01/04/2023] Open
Abstract
A multimodality approach was applied using four-dimensional flow magnetic resonance imaging (4D flow MRI), time-of-flight magnetic resonance angiography (TOF-MRA) signal intensity gradient (SIG), and computational fluid dynamics (CFD) to investigate the 3D blood flow characteristics and wall shear stress (WSS) of the cerebral arteries. TOF-MRA and 4D flow MRI were performed on the major cerebral arteries in 16 healthy volunteers (mean age 34.7 ± 7.6 years). The flow rate measured with 4D flow MRI in the internal carotid artery, middle cerebral artery, and anterior cerebral artery were 3.8, 2.5, and 1.2 mL/s, respectively. The 3D blood flow pattern obtained through CFD and 4D flow MRI on the cerebral arteries showed reasonable consensus. CFD delivered much greater resolution than 4D flow MRI. TOF-MRA SIG and CFD WSS of the major cerebral arteries showed reasonable consensus with the locations where the WSS was relatively high. However, the visualizations were very different between TOF-MRA SIG and CFD WSS at the internal carotid artery bifurcations, the anterior cerebral arteries, and the anterior communicating arteries. 4D flow MRI, TOF-MRA SIG, and CFD are complementary methods that can provide additional insight into the hemodynamics of the human cerebral artery.
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Affiliation(s)
- Minh Tri Ngo
- Department of Radiology and Research Institute of Clinical Medicine of Jeonbuk National University, Biomedical Research Institute of Jeonbuk National University Hospital, Jeon-ju 54907, Korea; (M.T.N.); (G.H.C.); (Y.G.K.)
| | - Ui Yun Lee
- Division of Mechanical Design Engineering, Jeonbuk National University, Jeon-ju 54896, Korea;
| | - Hojin Ha
- Department of Mechanical and Biomedical Engineering, Kangwon National University, Chuncheon 24341, Korea;
| | - Ning Jin
- Siemens Medical Solutions USA, Inc., Chicago, IL 60089, USA;
| | - Gyung Ho Chung
- Department of Radiology and Research Institute of Clinical Medicine of Jeonbuk National University, Biomedical Research Institute of Jeonbuk National University Hospital, Jeon-ju 54907, Korea; (M.T.N.); (G.H.C.); (Y.G.K.)
| | - Yeong Gon Kwak
- Department of Radiology and Research Institute of Clinical Medicine of Jeonbuk National University, Biomedical Research Institute of Jeonbuk National University Hospital, Jeon-ju 54907, Korea; (M.T.N.); (G.H.C.); (Y.G.K.)
| | - Jinmu Jung
- Division of Mechanical Design Engineering, Jeonbuk National University, Jeon-ju 54896, Korea;
- Hemorheology Research Institute, Jeonbuk National University, Jeon-ju 54896, Korea
- Correspondence: (J.J.); (H.S.K.); Tel.: +82-63-270-3998 (J.J.); +82-63-250-2582 (H.S.K.)
| | - Hyo Sung Kwak
- Department of Radiology and Research Institute of Clinical Medicine of Jeonbuk National University, Biomedical Research Institute of Jeonbuk National University Hospital, Jeon-ju 54907, Korea; (M.T.N.); (G.H.C.); (Y.G.K.)
- Correspondence: (J.J.); (H.S.K.); Tel.: +82-63-270-3998 (J.J.); +82-63-250-2582 (H.S.K.)
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16
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Ziegler M, Alfraeus J, Good E, Engvall J, de Muinck E, Dyverfeldt P. Exploring the Relationships Between Hemodynamic Stresses in the Carotid Arteries. Front Cardiovasc Med 2021; 7:617755. [PMID: 33614742 PMCID: PMC7886794 DOI: 10.3389/fcvm.2020.617755] [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] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/31/2020] [Indexed: 11/13/2022] Open
Abstract
Background: Atherosclerosis manifests as a focal disease, often affecting areas with complex hemodynamics such as the carotid bifurcation. The magnitude and regularity of the hemodynamic shear stresses acting on the vessel wall are thought to generate risk patterns unique to each patient and play a role in the pathogenesis of atherosclerosis. The involvement of different expressions of shear stress in the pathogenesis of carotid atherosclerosis highlights the need to characterize and compare the differential impact of the various expressions of shear stress in the atherosclerotic carotid bifurcation. Therefore, the aim of this study is to characterize and compare hemodynamic wall shear stresses (WSS) in the carotid arteries of subjects with asymptomatic atherosclerotic plaques. Shear stresses were also compared against vessel diameter and bifurcation angle to examine the relationships with the geometry of the carotid bifurcation. Methods: 4D Flow MRI and contrast-enhanced MRA data were acquired for 245 subjects with atherosclerotic plaques of at least 2.7 mm in conjunction with the Swedish CArdioPulmonary bioImage Study (SCAPIS). Following automatic segmentation and geometric analysis, time-resolved WSS and near-wall turbulent kinetic energy (nwTKE) were derived from the 4D Flow data. Whole-cycle parameters including time-averaged WSS and nwTKE, and the oscillatory shear index (OSI) were calculated. Pairwise Spearman rank-correlation analyses were used to investigate relationships among the hemodynamic as well as geometric parameters. Results: One hundred and seventy nine subjects were successfully segmented using automated tools and subsequently geometric and hemodynamic analyses were performed. Temporally resolved WSS and nwTKE were strongly correlated, ρ = 0.64. Cycle-averaged WSS and nwTKE were moderately correlated, ρ = 0.57. Cycle-average nwTKE was weakly correlated to OSI (ρ = -0.273), revealing that nwTKE provides information about disturbed flow on the vessel wall that OSI does not. In this cohort, there was large inter-individual variation for both WSS and nwTKE. Both WSS and nwTKE varied most within the external carotid artery. WSS, nwTKE, and OSI were weakly correlated to vessel diameter and bifurcation angle. Conclusion: The turbulent and mean component of WSS were examined together in vivo for the first time, and a strong correlation was found between them. nwTKE presents the opportunity to quantify turbulent wall stresses in vivo and gain insight into the effects of disturbed flow on the vessel wall. Neither vessel diameter nor bifurcation angle were found to be strongly correlated to the turbulent or mean component of WSS in this cohort.
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Affiliation(s)
- Magnus Ziegler
- Division of Cardiovascular Medicine, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Jesper Alfraeus
- Division of Cardiovascular Medicine, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Elin Good
- Division of Cardiovascular Medicine, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.,Department of Cardiology, Linköping University, Linköping, Sweden
| | - Jan Engvall
- Division of Cardiovascular Medicine, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.,Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Ebo de Muinck
- Division of Cardiovascular Medicine, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.,Department of Cardiology, Linköping University, Linköping, Sweden
| | - Petter Dyverfeldt
- Division of Cardiovascular Medicine, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
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17
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Hoving AM, Voorneveld J, Mikhal J, Bosch JG, Groot Jebbink E, Slump CH. In vitro performance of echoPIV for assessment of laminar flow profiles in a carotid artery stent. J Med Imaging (Bellingham) 2021; 8:017001. [PMID: 33457445 PMCID: PMC7804295 DOI: 10.1117/1.jmi.8.1.017001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 12/22/2020] [Indexed: 11/14/2022] Open
Abstract
Purpose: Detailed blood flow studies may contribute to improvements in carotid artery stenting. High-frame-rate contrast-enhanced ultrasound followed by particle image velocimetry (PIV), also called echoPIV, is a technique to study blood flow patterns in detail. The performance of echoPIV in presence of a stent has not yet been studied extensively. We compared the performance of echoPIV in stented and nonstented regions in an in vitro flow setup. Approach: A carotid artery stent was deployed in a vessel-mimicking phantom. High-frame-rate contrast-enhanced ultrasound images were acquired with various settings. Signal intensities of the contrast agent, velocity values, and flow profiles were calculated. Results: The results showed decreased signal intensities and correlation coefficients inside the stent, however, PIV analysis in the stent still resulted in plausible flow vectors. Conclusions: Velocity values and laminar flow profiles can be measured in vitro in stented arteries using echoPIV.
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Affiliation(s)
- Astrid M Hoving
- University of Twente, TechMed Centre, Robotics and Mechatronics Group, Enschede, The Netherlands
| | - Jason Voorneveld
- Erasmus MC, Thorax Center, Department of Biomedical Engineering, Rotterdam, The Netherlands
| | - Julia Mikhal
- University of Twente, TechMed Centre, BIOS Lab-on-a-Chip Group, Enschede, The Netherlands
| | - Johan G Bosch
- Erasmus MC, Thorax Center, Department of Biomedical Engineering, Rotterdam, The Netherlands
| | - Erik Groot Jebbink
- University of Twente, TechMed Centre, Multi-Modality Medical Imaging Group, Enschede, The Netherlands
| | - Cornelis H Slump
- University of Twente, TechMed Centre, Robotics and Mechatronics Group, Enschede, The Netherlands
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18
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Lu Q, Lin W, Zhang R, Chen R, Wei X, Li T, Du Z, Xie Z, Yu Z, Xie X, Liu H. Validation and Diagnostic Performance of a CFD-Based Non-invasive Method for the Diagnosis of Aortic Coarctation. Front Neuroinform 2020; 14:613666. [PMID: 33362500 PMCID: PMC7756015 DOI: 10.3389/fninf.2020.613666] [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: 10/03/2020] [Accepted: 11/13/2020] [Indexed: 11/30/2022] Open
Abstract
Purpose: The clinical diagnosis of aorta coarctation (CoA) constitutes a challenge, which is usually tackled by applying the peak systolic pressure gradient (PSPG) method. Recent advances in computational fluid dynamics (CFD) have suggested that multi-detector computed tomography angiography (MDCTA)-based CFD can serve as a non-invasive PSPG measurement. The aim of this study was to validate a new CFD method that does not require any medical examination data other than MDCTA images for the diagnosis of CoA. Materials and methods: Our study included 65 pediatric patients (38 with CoA, and 27 without CoA). All patients underwent cardiac catheterization to confirm if they were suffering from CoA or any other congenital heart disease (CHD). A series of boundary conditions were specified and the simulated results were combined to obtain a stenosis pressure-flow curve. Subsequently, we built a prediction model and evaluated its predictive performance by considering the AUC of the ROC by 5-fold cross-validation. Results: The proposed MDCTA-based CFD method exhibited a good predictive performance in both the training and test sets (average AUC: 0.948 vs. 0.958; average accuracies: 0.881 vs. 0.877). It also had a higher predictive accuracy compared with the non-invasive criteria presented in the European Society of Cardiology (ESC) guidelines (average accuracies: 0.877 vs. 0.539). Conclusion: The new non-invasive CFD-based method presented in this work is a promising approach for the accurate diagnosis of CoA, and will likely benefit clinical decision-making.
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Affiliation(s)
- Qiyang Lu
- College of Automation Science and Technology, South China University of Technology, Guangzhou, China.,Department of Radiology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Weiyuan Lin
- College of Automation Science and Technology, South China University of Technology, Guangzhou, China.,Department of Radiology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Ruichen Zhang
- Department of Information Engineering, Northwestern Polytechnical University, Xi'an, China
| | - Rui Chen
- Department of Radiology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Xiaoyu Wei
- Department of Radiology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Tingyu Li
- Department of Radiology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Zhicheng Du
- Guangdong Key Laboratory of Medicine, Department of Medical Statistics and Epidemiology, Health Information Research Center, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Zhaofeng Xie
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Zhuliang Yu
- College of Automation Science and Technology, South China University of Technology, Guangzhou, China.,School of Medicine, South China University of Technology, Guangzhou, China
| | - Xinzhou Xie
- Department of Information Engineering, Northwestern Polytechnical University, Xi'an, China
| | - Hui Liu
- Department of Radiology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,School of Medicine, South China University of Technology, Guangzhou, China
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19
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Youn SW, Lee J. From 2D to 4D Phase-Contrast MRI in the Neurovascular System: Will It Be a Quantum Jump or a Fancy Decoration? J Magn Reson Imaging 2020; 55:347-372. [PMID: 33236488 DOI: 10.1002/jmri.27430] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 12/16/2022] Open
Abstract
Considering the crosstalk between the flow and vessel wall, hemodynamic assessment of the neurovascular system may offer a well-integrated solution for both diagnosis and management by adding prognostic significance to the standard CT/MR angiography. 4D flow MRI or time-resolved 3D velocity-encoded phase-contrast MRI has long been promising for the hemodynamic evaluation of the great vessels, but challenged in clinical studies for assessing intracranial vessels with small diameter due to long scan times and low spatiotemporal resolution. Current accelerated MRI techniques, including parallel imaging with compressed sensing and radial k-space undersampling acquisitions, have decreased scan times dramatically while preserving spatial resolution. 4D flow MRI visualized and measured 3D complex flow of neurovascular diseases such as aneurysm, arteriovenous shunts, and atherosclerotic stenosis using parameters including flow volume, velocity vector, pressure gradients, and wall shear stress. In addition to the noninvasiveness of the phase contrast technique and retrospective flow measurement through the wanted windows of the analysis plane, 4D flow MRI has shown several advantages over Doppler ultrasound or computational fluid dynamics. The evaluation of the flow status and vessel wall can be performed simultaneously in the same imaging modality. This article is an overview of the recent advances in neurovascular 4D flow MRI techniques and their potential clinical applications in neurovascular disease. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3.
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Affiliation(s)
- Sung Won Youn
- Department of Radiology, Catholic University of Daegu School of Medicine, Daegu, Korea
| | - Jongmin Lee
- Department of Radiology and Biomedical Engineering, Kyungpook National University School of Medicine, Daegu, Korea
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20
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Concannon J, Hynes N, McMullen M, Smyth E, Moerman K, McHugh PE, Sultan S, Karmonik C, McGarry JP. A Dual-VENC Four-Dimensional Flow MRI Framework for Analysis of Subject-Specific Heterogeneous Nonlinear Vessel Deformation. J Biomech Eng 2020; 142:114502. [PMID: 33006370 DOI: 10.1115/1.4048649] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Indexed: 07/25/2024]
Abstract
Advancement of subject-specific in silico medicine requires new imaging protocols tailored to specific anatomical features, paired with new constitutive model development based on structure/function relationships. In this study, we develop a new dual-velocity encoding coefficient (VENC) 4D flow MRI protocol that provides unprecedented spatial and temporal resolution of in vivo aortic deformation. All previous dual-VENC 4D flow MRI studies in the literature focus on an isolated segment of the aorta, which fail to capture the full spectrum of aortic heterogeneity that exists along the vessel length. The imaging protocol developed provides high sensitivity to all blood flow velocities throughout the entire cardiac cycle, overcoming the challenge of accurately measuring the highly unsteady nonuniform flow field in the aorta. Cross-sectional area change, volumetric flow rate, and compliance are observed to decrease with distance from the heart, while pulse wave velocity (PWV) is observed to increase. A nonlinear aortic lumen pressure-area relationship is observed throughout the aorta such that a high vessel compliance occurs during diastole, and a low vessel compliance occurs during systole. This suggests that a single value of compliance may not accurately represent vessel behavior during a cardiac cycle in vivo. This high-resolution MRI data provide key information on the spatial variation in nonlinear aortic compliance, which can significantly advance the state-of-the-art of in-silico diagnostic techniques for the human aorta.
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Affiliation(s)
- J Concannon
- Biomedical Engineering, National University of Ireland Galway, Galway H91 TK33, Ireland
| | - N Hynes
- Department of Vascular and Endovascular Surgery, National University of Ireland Galway, Galway H91 TK33, Ireland
| | - M McMullen
- Department of Radiology, Galway Clinic, Doughiska, Galway H91 HHT0, Ireland
| | - E Smyth
- Department of Radiology, Galway Clinic, Doughiska, Galway H91 HHT0, Ireland
| | - K Moerman
- Biomedical Engineering, National University of Ireland Galway, Galway H91 TK33, Ireland
| | - P E McHugh
- Biomedical Engineering, National University of Ireland Galway, Galway H91 TK33, Ireland
| | - S Sultan
- Department of Vascular and Endovascular Surgery, National University of Ireland Galway, Galway H91 TK33, Ireland
| | - C Karmonik
- MRI Core, Houston Methodist Debakey Heart and Vascular Center, Houston, TX 77030
| | - J P McGarry
- Biomedical Engineering, National University of Ireland Galway, Galway H91 TK33, Ireland
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21
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Pathrose A, Ma L, Berhane H, Scott MB, Chow K, Forman C, Jin N, Serhal A, Avery R, Carr J, Markl M. Highly accelerated aortic 4D flow MRI using compressed sensing: Performance at different acceleration factors in patients with aortic disease. Magn Reson Med 2020; 85:2174-2187. [PMID: 33107141 DOI: 10.1002/mrm.28561] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 09/29/2020] [Accepted: 09/30/2020] [Indexed: 12/16/2022]
Abstract
PURPOSE To systematically assess the feasibility and performance of a highly accelerated compressed sensing (CS) 4D flow MRI framework at three different acceleration factors (R) for the quantification of aortic flow dynamics and wall shear stress (WSS) in patients with aortic disease. METHODS Twenty patients with aortic disease (58 ± 15 y old; 19 M) underwent four 4D flow scans: one conventional (GRAPPA, R = 2) and three CS 4D flows with R = 5.7, 7.7, and 10.2. All scans were acquired with otherwise equivalent imaging parameters on a 1.5T scanner. Peak-systolic velocity (Vmax ), peak flow (Qmax ), and net flow (Qnet ) were quantified at the ascending aorta (AAo), arch, and descending aorta (DAo). WSS was calculated at six regions within the AAo and arch. RESULTS Mean scan times for the conventional and CS 4D flows with R = 5.7, 7.7, and 10.2 were 9:58 ± 2:58 min, 3:40 ± 1:19 min, 2:50 ± 0:56 min, and 2:05 ± 0:42 min, respectively. Vmax , Qmax , and Qnet were significantly underestimated by all CS protocols (underestimation ≤ -7%, -9%, and -10% by CS, R = 5.7, 7.7, and 10.2, respectively). WSS measurements showed the highest underestimation by all CS protocols (underestimation ≤ -9%, -12%, and -14% by CS, R = 5.7, 7.7, and 10.2). CONCLUSIONS Highly accelerated aortic CS 4D flow at R = 5.7, 7.7, and 10.2 showed moderate agreement with the conventional 4D flow, despite systematically underestimating various hemodynamic parameters. The shortened scan time may enable the clinical translation of CS 4D flow, although potential hemodynamic underestimation should be considered when interpreting the results.
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Affiliation(s)
- Ashitha Pathrose
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Liliana Ma
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA
| | - Haben Berhane
- Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
| | - Michael B Scott
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA
| | - Kelvin Chow
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Cardiovascular MR R&D, Siemens Medical Solutions USA, Inc., Chicago, Illinois, USA
| | | | - Ning Jin
- Cardiovascular MR R&D, Siemens Medical Solutions USA, Inc., Chicago, Illinois, USA
| | - Ali Serhal
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Ryan Avery
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - James Carr
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA
| | - Michael Markl
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA
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22
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Hoeijmakers MJMM, Waechter‐Stehle I, Weese J, Van de Vosse FN. Combining statistical shape modeling, CFD, and meta-modeling to approximate the patient-specific pressure-drop across the aortic valve in real-time. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3387. [PMID: 32686898 PMCID: PMC7583374 DOI: 10.1002/cnm.3387] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 06/13/2020] [Accepted: 07/15/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Advances in medical imaging, segmentation techniques, and high performance computing have stimulated the use of complex, patient-specific, three-dimensional Computational Fluid Dynamics (CFD) simulations. Patient-specific, CFD-compatible geometries of the aortic valve are readily obtained. CFD can then be used to obtain the patient-specific pressure-flow relationship of the aortic valve. However, such CFD simulations are computationally expensive, and real-time alternatives are desired. AIM The aim of this work is to evaluate the performance of a meta-model with respect to high-fidelity, three-dimensional CFD simulations of the aortic valve. METHODS Principal component analysis was used to build a statistical shape model (SSM) from a population of 74 iso-topological meshes of the aortic valve. Synthetic meshes were created with the SSM, and steady-state CFD simulations at flow-rates between 50 and 650 mL/s were performed to build a meta-model. The meta-model related the statistical shape variance, and flow-rate to the pressure-drop. RESULTS Even though the first three shape modes account for only 46% of shape variance, the features relevant for the pressure-drop seem to be captured. The three-mode shape-model approximates the pressure-drop with an average error of 8.8% to 10.6% for aortic valves with a geometric orifice area below 150 mm2 . The proposed methodology was least accurate for aortic valve areas above 150 mm2 . Further reduction to a meta-model introduces an additional 3% error. CONCLUSIONS Statistical shape modeling can be used to capture shape variation of the aortic valve. Meta-models trained by SSM-based CFD simulations can provide an estimate of the pressure-flow relationship in real-time.
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Affiliation(s)
- M. J. M. M. Hoeijmakers
- Department of Biomedical EngineeringEindhoven University of TechnologyEindhovenThe Netherlands
- ANSYS IncVilleurbanneFrance
| | | | | | - F. N. Van de Vosse
- Department of Biomedical EngineeringEindhoven University of TechnologyEindhovenThe Netherlands
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23
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Levilly S, Castagna M, Idier J, Bonnefoy F, Le Touzé D, Moussaoui S, Paul-Gilloteaux P, Serfaty JM. Towards quantitative evaluation of wall shear stress from 4D flow imaging. Magn Reson Imaging 2020; 74:232-243. [PMID: 32889090 DOI: 10.1016/j.mri.2020.08.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 06/12/2020] [Accepted: 08/23/2020] [Indexed: 11/25/2022]
Abstract
Wall shear stress (WSS) is a relevant hemodynamic indicator of the local stress applied on the endothelium surface. More specifically, its spatiotemporal distribution reveals crucial in the evolution of many pathologies such as aneurysm, stenosis, and atherosclerosis. This paper introduces a new solution, called PaLMA, to quantify the WSS from 4D Flow MRI data. It relies on a two-step local parametric model, to accurately describe the vessel wall and the velocity-vector field in the neighborhood of a given point of interest. Extensive validations have been performed on synthetic 4D Flow MRI data, including four datasets generated from patient specific computational fluid dynamics simulations on carotids. The validation tests are focused on the impact of the noise component, of the resolution level, and of the segmentation accuracy concerning the vessel position in the context of complex flow patterns. In simulated cases aimed to reproduce clinical acquisition conditions, the WSS quantification performance reached by PaLMA is significantly higher (with a gain in RMSE of 12 to 27%) than the reference one obtained using the smoothing B-spline method proposed by Potters et al. (2015) method, while the computation time is equivalent for both WSS quantification methods.
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Affiliation(s)
- Sébastien Levilly
- Laboratoire des Sciences du Numérique de Nantes (ECN and CNRS), 1 rue de la Noë, BP 92101, 44321 Nantes Cedex 3, France.
| | - Marco Castagna
- Ecole Centrale de Nantes, LHEEA Lab (ECN and CNRS), 1 rue de la Noë, 44300 Nantes, France; Université de Nantes, CHU Nantes, CNRS UMR 6291, INSERM UMR 1087, L'institut du thorax, F-44000 Nantes, France
| | - Jérôme Idier
- Laboratoire des Sciences du Numérique de Nantes (ECN and CNRS), 1 rue de la Noë, BP 92101, 44321 Nantes Cedex 3, France
| | - Félicien Bonnefoy
- Ecole Centrale de Nantes, LHEEA Lab (ECN and CNRS), 1 rue de la Noë, 44300 Nantes, France
| | - David Le Touzé
- Ecole Centrale de Nantes, LHEEA Lab (ECN and CNRS), 1 rue de la Noë, 44300 Nantes, France
| | - Saïd Moussaoui
- Laboratoire des Sciences du Numérique de Nantes (ECN and CNRS), 1 rue de la Noë, BP 92101, 44321 Nantes Cedex 3, France
| | - Perrine Paul-Gilloteaux
- Université de Nantes, CHU Nantes, CNRS UMR 6291, INSERM UMR 1087, L'institut du thorax, F-44000 Nantes, France; Université de Nantes, CHU Nantes, Inserm, CNRS, SFR Santé, Inserm UMS 016, CNRS UMS 3556, F-44000 Nantes, France
| | - Jean-Michel Serfaty
- Université de Nantes, CHU Nantes, CNRS UMR 6291, INSERM UMR 1087, L'institut du thorax, F-44000 Nantes, France
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24
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Castle-Kirszbaum M, Maingard J, Lim RP, Barras CD, Kok HK, Chandra RV, Chong W, Asadi H. Four-Dimensional Magnetic Resonance Imaging Assessment of Intracranial Aneurysms: A State-of-the-Art Review. Neurosurgery 2020; 87:453-465. [PMID: 32140714 DOI: 10.1093/neuros/nyaa021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 12/15/2019] [Indexed: 11/14/2022] Open
Abstract
Treatment of unruptured intracranial aneurysms can reduce the risk of subarachnoid hemorrhage and its associated morbidity and mortality. However, current methods to predict the risk of rupture and optimize treatment strategies for intracranial aneurysms are limited. Assessment of intra-aneurysmal flow using 4-dimensional magnetic resonance imaging (4D MRI) is a novel tool that could be used to guide therapy. A systematic search of the literature was performed to provide a state-of-the-art review on 4D MRI assessment of unruptured intracranial aneurysms. A total of 18 studies were available for review. Eccentric flow on 4D MRI is associated with a greater aspect ratio and peak wall shear stress (WSS). WSS, vorticity, and peak velocity are greater in saccular than fusiform aneurysms. Unstable aneurysms are associated with greater WSS, peak wall stress, and flow jet angle and may exhibit wall enhancement. In comparison to computational fluid dynamics (CFD), 4D MRI has a lower spatial resolution and reports lower WSS and velocity magnitudes, but these parameters equalize when spatial resolution is matched. 4D MRI demonstrates the intra-aneurysmal hemodynamic changes associated with flow diversion, including significantly decreased flow velocity. Thus, 4D MRI is a novel, noninvasive imaging tool used for the evaluation of hemodynamics within intracranial aneurysms. Hemodynamic indices derived from 4D MRI appear to correlate well with the simulated (CFD) values and may be used to measure the success of endovascular therapies and risk factors for aneurysm growth and rupture.
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Affiliation(s)
- Mendel Castle-Kirszbaum
- NeuroInterventional Radiology Unit, Monash Health, Melbourne, Australia.,Department of Neurosurgery, Monash Health, Melbourne, Australia
| | - Julian Maingard
- NeuroInterventional Radiology Unit, Monash Health, Melbourne, Australia.,Department of Imaging, Monash Health, Melbourne, Australia.,School of Medicine, Deakin University, Victoria, Australia
| | - Ruth P Lim
- Austin Health, Melbourne, Australia.,The University of Melbourne, Melbourne, Australia
| | - Christen D Barras
- Department of Radiology, Royal Adelaide Hospital, The University of Adelaide, Australia.,South Australian Health and Medical Research Institute, Adelaide, Australia
| | - Hong Kuan Kok
- School of Medicine, Deakin University, Victoria, Australia.,Department of Radiology Northern Health, Melbourne, Australia
| | - Ronil V Chandra
- NeuroInterventional Radiology Unit, Monash Health, Melbourne, Australia.,Department of Imaging, Monash Health, Melbourne, Australia.,Monash University, Melbourne, Australia
| | - Winston Chong
- NeuroInterventional Radiology Unit, Monash Health, Melbourne, Australia.,Department of Imaging, Monash Health, Melbourne, Australia.,Monash University, Melbourne, Australia
| | - Hamed Asadi
- NeuroInterventional Radiology Unit, Monash Health, Melbourne, Australia.,Department of Imaging, Monash Health, Melbourne, Australia.,School of Medicine, Deakin University, Victoria, Australia.,Austin Health, Melbourne, Australia
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25
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Schmitter S, Adriany G, Waks M, Moeller S, Aristova M, Vali A, Auerbach EJ, Van de Moortele PF, Ugurbil K, Schnell S. Bilateral Multiband 4D Flow MRI of the Carotid Arteries at 7T. Magn Reson Med 2020; 84:1947-1960. [PMID: 32187742 DOI: 10.1002/mrm.28256] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/31/2020] [Accepted: 02/24/2020] [Indexed: 12/26/2022]
Abstract
PURPOSE Simultaneous multislab (SMSb) 4D flow MRI was developed and implemented at 7T for accelerated acquisition of the 3D blood velocity vector field in both carotid bifurcations. METHODS SMSb was applied to 4D flow to acquire blood velocities in both carotid bifurcations in sagittal orientation using a local transmit/receive coil at 7T. B 1 + transmit efficiency was optimized by B 1 + shimming. SMSb 4D flow was obtained in 8 healthy subjects in single-band (SB) and multiband (MB) fashion. Additionally, MB data were retrospectively undersampled to simulate GRAPPA R = 2 (MB2_GRAPPA2), and both SB datasets were added to form an artificial MB dataset (SumSB). The band separation performance was quantified by signal leakage. Peak velocity and total flow values were calculated and compared to SB via intraclass correlation analysis (ICC). RESULTS Clean slab separation was achieved yielding a mean signal leakage of 13% above the mean SB noise level. Mean total flow for MB2, SumSB, and MB_GRAPPA2 deviated less than 9% from the SB values. Peak velocities averaged over all vessels and subjects were 0.48 ± 0.11 m/s for SB, 0.47 ± 0.12 m/s for SumSB, 0.50 ± 0.13 m/s for MB2, and 0.53 ± 0.13 m/s for MB2_GRAPPA2. ICC revealed excellent absolute agreement and consistency of total flow for all methods compared to SB2. Peak velocity showed good to excellent agreement and consistency for SumSB and MB2 and MB2_GRAPPA2 method showed poor to excellent agreement and good to excellent consistency. CONCLUSION Simultaneous multislab 4D Flow MRI allows accurate quantification of total flow and peak velocity while reducing scan times.
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Affiliation(s)
- Sebastian Schmitter
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA.,Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin, Germany
| | - Gregor Adriany
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Matt Waks
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Steen Moeller
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Maria Aristova
- McCormick School of Engineering, Northwestern University, Evanston, USA.,Feinberg School of Medicine, Northwestern University, Chicago, USA
| | - Alireza Vali
- Feinberg School of Medicine, Northwestern University, Chicago, USA
| | - Edward J Auerbach
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | | | - Kamil Ugurbil
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Susanne Schnell
- Feinberg School of Medicine, Northwestern University, Chicago, USA
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26
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Four-Dimensional Flow Magnetic Resonance Imaging for Assessment of Velocity Magnitudes and Flow Patterns in The Human Carotid Artery Bifurcation: Comparison with Computational Fluid Dynamics. Diagnostics (Basel) 2019; 9:diagnostics9040223. [PMID: 31847224 PMCID: PMC6963916 DOI: 10.3390/diagnostics9040223] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 11/22/2019] [Accepted: 12/12/2019] [Indexed: 11/17/2022] Open
Abstract
Purpose: Knowledge of the hemodynamics in the vascular system is important to understand and treat vascular pathology. The present study aimed to evaluate the hemodynamics in the human carotid artery bifurcation measured by four-dimensional (4D) flow magnetic resonance imaging (MRI) as compared to computational fluid dynamics (CFD). Methods: This protocol used MRI data of 12 healthy volunteers for the 3D vascular models and 4D flow MRI measurements for the boundary conditions in CFD simulation. We compared the velocities measured at the carotid bifurcation and the 3D velocity streamlines of the carotid arteries obtained by these two methods. Results: There was a good agreement for both maximum and minimum velocity values between the 2 methods for velocity magnitude at the bifurcation plane. However, on the 3D blood flow visualization, secondary flows, and recirculation regions are of poorer quality when visualized through the 4D flow MRI. Conclusion: 4D flow MRI and CFD show reasonable agreement in demonstrated velocity magnitudes at the carotid artery bifurcation. However, the visualization of blood flow at the recirculation regions and the assessment of secondary flow characteristics should be enhanced for the use of 4D flow MRI in clinical situations.
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27
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Steinman DA, Migliavacca F. Editorial: Special Issue on Verification, Validation, and Uncertainty Quantification of Cardiovascular Models: Towards Effective VVUQ for Translating Cardiovascular Modelling to Clinical Utility. Cardiovasc Eng Technol 2019; 9:539-543. [PMID: 30421097 DOI: 10.1007/s13239-018-00393-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- David A Steinman
- Biomedical Simulation Laboratory (BSL), Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada.
| | - Francesco Migliavacca
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering 'Giulio Natta', Politecnico di Milano, Milan, Italy
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28
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Moerman AM, Dilba K, Korteland S, Poot DHJ, Klein S, van der Lugt A, Rouwet EV, van Gaalen K, Wentzel JJ, van der Steen AFW, Gijsen FJH, Van der Heiden K. An MRI-based method to register patient-specific wall shear stress data to histology. PLoS One 2019; 14:e0217271. [PMID: 31170183 PMCID: PMC6553699 DOI: 10.1371/journal.pone.0217271] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 04/27/2019] [Indexed: 11/18/2022] Open
Abstract
Wall shear stress (WSS), the frictional force exerted on endothelial cells by blood flow, is hypothesised to influence atherosclerotic plaque growth and composition. We developed a methodology for image registration of MR and histology images of advanced human carotid plaques and corresponding WSS data, obtained by MRI and computational fluid dynamics. The image registration method requires four types of input images, in vivo MRI, ex vivo MRI, photographs of transversally sectioned plaque tissue and histology images. These images are transformed to a shared 3D image domain by applying a combination of rigid and non-rigid registration algorithms. Transformation matrices obtained from registration of these images are used to transform subject-specific WSS data to the shared 3D image domain as well. WSS values originating from the 3D WSS map are visualised in 2D on the corresponding lumen locations in the histological sections and divided into eight radial segments. In each radial segment, the correlation between WSS values and plaque composition based on histological parameters can be assessed. The registration method was successfully applied to two carotid endarterectomy specimens. The resulting matched contours from the imaging modalities had Hausdorff distances between 0.57 and 0.70 mm, which is in the order of magnitude of the in vivo MRI resolution. We simulated the effect of a mismatch in the rigid registration of imaging modalities on WSS results by relocating the WSS data with respect to the stack of histology images. A 0.6 mm relocation altered the mean WSS values projected on radial bins on average by 0.59 Pa, compared to the output of original registration. This mismatch of one image slice did not change the correlation between WSS and plaque thickness. In conclusion, we created a method to investigate correlations between WSS and plaque composition.
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Affiliation(s)
- A. M. Moerman
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, The Netherlands
| | - K. Dilba
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, The Netherlands
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - S. Korteland
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, The Netherlands
| | - D. H. J. Poot
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
- Department of Medical Informatics, Erasmus MC, Rotterdam, The Netherlands
| | - S. Klein
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
- Department of Medical Informatics, Erasmus MC, Rotterdam, The Netherlands
| | - A. van der Lugt
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - E. V. Rouwet
- Department of Surgery, Erasmus MC, Rotterdam, The Netherlands
| | - K. van Gaalen
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, The Netherlands
| | - J. J. Wentzel
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, The Netherlands
| | | | - F. J. H. Gijsen
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, The Netherlands
| | - K. Van der Heiden
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, The Netherlands
- * E-mail:
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29
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Sáez P, Gallo D, Morbiducci U. Mechanotransmission of haemodynamic forces by the endothelial glycocalyx in a full-scale arterial model. ROYAL SOCIETY OPEN SCIENCE 2019; 6:190607. [PMID: 31312506 PMCID: PMC6599767 DOI: 10.1098/rsos.190607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 05/14/2019] [Indexed: 06/10/2023]
Abstract
The glycocalyx has been identified as a key mechano-sensor of the shear forces exerted by streaming blood onto the vascular endothelial lining. Although the biochemical reaction to the blood flow has been extensively studied, the mechanism of transmission of the haemodynamic shear forces to the endothelial transmembrane anchoring structures and, consequently, to the subcellular elements in the cytoskeleton, is still not fully understood. Here we apply a multiscale approach to elucidate how haemodynamic shear forces are transmitted to the transmembrane anchors of endothelial cells. Wall shear stress time histories, as obtained from image-based computational haemodynamics models of a carotid bifurcation, are used as a load and a continuum model is applied to obtain the mechanical response of the glycocalyx all along the cardiac cycle. The main findings of this in silico study are that: (1) the forces transmitted to the transmembrane anchors are in the range of 1-10 pN, which is in the order of magnitude reported for the different conformational states of transmembrane mechanotranductors; (2) locally, the forces transmitted to the anchors of the glycocalyx structure can be markedly different from the near-wall haemodynamic shear forces both in amplitude and frequency content. The findings of this in silico approach warrant future studies focusing on the actual forces transmitted to the transmembrane mechanotransductors, which might outperform haemodynamic descriptors of disturbed shear as localizing factors of vascular disease.
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Affiliation(s)
- P. Sáez
- Laboratori de Càlcul Numèric (LàCaN), Universitat Politècnica de Catalunya, Barcelona, Spain
- Barcelona Graduate School of Mathematics (BGSMath), Barcelona, Spain
| | - D. Gallo
- PoliTo Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Torino, Italy
| | - U. Morbiducci
- PoliTo Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Torino, Italy
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Modern Concepts in Regenerative Therapy for Ischemic Stroke: From Stem Cells for Promoting Angiogenesis to 3D-Bioprinted Scaffolds Customized via Carotid Shear Stress Analysis. Int J Mol Sci 2019; 20:ijms20102574. [PMID: 31130624 PMCID: PMC6566983 DOI: 10.3390/ijms20102574] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 05/20/2019] [Accepted: 05/22/2019] [Indexed: 02/06/2023] Open
Abstract
Ischemic stroke is associated with a tremendous economic and societal burden, and only a few therapies are currently available for the treatment of this devastating disease. The main therapeutic approaches used nowadays for the treatment of ischemic brain injury aim to achieve reperfusion, neuroprotection and neurorecovery. Therapeutic angiogenesis also seems to represent a promising tool to improve the prognosis of cerebral ischemia. This review aims to present the modern concepts and the current status of regenerative therapy for ischemic stroke and discuss the main results of major clinical trials addressing the effectiveness of stem cell therapy for achieving neuroregeneration in ischemic stroke. At the same time, as a glimpse into the future, this article describes modern concepts for stroke prevention, such as the implantation of bioprinted scaffolds seeded with stem cells, whose 3D geometry is customized according to carotid shear stress.
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Puiseux T, Sewonu A, Meyrignac O, Rousseau H, Nicoud F, Mendez S, Moreno R. Reconciling PC-MRI and CFD: An in-vitro study. NMR IN BIOMEDICINE 2019; 32:e4063. [PMID: 30747461 DOI: 10.1002/nbm.4063] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 11/16/2018] [Accepted: 12/18/2018] [Indexed: 05/25/2023]
Abstract
Several well-resolved 4D Flow MRI acquisitions of an idealized rigid flow phantom featuring an aneurysm, a curved channel as well as a bifurcation were performed under pulsatile regime. The resulting hemodynamics were processed to remove MRI artifacts. Subsequently, they were compared with CFD predictions computed on the same flow domain, using an in-house high-order low dissipative flow solver. Results show that reaching a good agreement is not straightforward but requires proper treatments of both techniques. Several sources of discrepancies are highlighted and their impact on the final correlation evaluated. While a very poor correlation (r2 = 0.63) is found in the entire domain between raw MRI and CFD data, correlation as high as r2 = 0.97 is found when artifacts are removed by post-processing the MR data and down sampling the CFD results to match the MRI spatial and temporal resolutions. This work demonstrates that, in a well-controlled environment, both PC-MRI and CFD might bring reliable and correlated flow quantities when a proper methodology to reduce the errors is followed.
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Affiliation(s)
- Thomas Puiseux
- IMAG, Univ Montpellier, CNRS, Montpellier, France
- ALARA Expertise, Strasbourg, France
| | - Anou Sewonu
- ALARA Expertise, Strasbourg, France
- I2MC, INSERM U1048, Toulouse, France
| | - Olivier Meyrignac
- I2MC, INSERM U1048, Toulouse, France
- Department of Radiology, CHU de Toulouse, Toulouse, France
| | - Hervé Rousseau
- I2MC, INSERM U1048, Toulouse, France
- Department of Radiology, CHU de Toulouse, Toulouse, France
| | | | - Simon Mendez
- IMAG, Univ Montpellier, CNRS, Montpellier, France
| | - Ramiro Moreno
- ALARA Expertise, Strasbourg, France
- I2MC, INSERM U1048, Toulouse, France
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van Ooij P, Cibis M, Rowland EM, Vernooij MW, van der Lugt A, Weinberg PD, Wentzel JJ, Nederveen AJ. Spatial correlations between MRI-derived wall shear stress and vessel wall thickness in the carotid bifurcation. Eur Radiol Exp 2018; 2:27. [PMID: 30302598 PMCID: PMC6177500 DOI: 10.1186/s41747-018-0058-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 06/29/2018] [Indexed: 11/17/2022] Open
Abstract
Background To explore the possibility of creating three-dimensional (3D) estimation models for patient-specific wall thickness (WT) maps using patient-specific and cohort-averaged WT, wall shear stress (WSS), and vessel diameter maps in asymptomatic atherosclerotic carotid bifurcations. Methods Twenty subjects (aged 75 ± 6 years [mean ± standard deviation], eight women) underwent a 1.5-T MRI examination. Non-gated 3D phase-contrast gradient-echo images and proton density-weighted echo-planar images were retrospectively assessed for WSS, diameter estimation, and WT measurements. Spearman’s ρ and scatter plots were used to determine correlations between individual WT, WSS, and diameter maps. A bootstrapping technique was used to determine correlations between 3D cohort-averaged WT, WSS, and diameter maps. Linear regression between the cohort-averaged WT, WSS, and diameter maps was used to predict individual 3D WT. Results Spearman’s ρ averaged over the subjects was − 0.24 ± 0.18 (p < 0.001) and 0.07 ± 0.28 (p = 0.413) for WT versus WSS and for WT versus diameter relations, respectively. Cohort-averaged ρ, averaged over 1000 bootstraps, was − 0.56 (95% confidence interval [− 0.74,− 0.38]) for WT versus WSS and 0.23 (95% confidence interval [− 0.06, 0.52]) for WT versus diameter. Scatter plots did not reveal relationships between individual WT and WSS or between WT and diameter data. Linear relationships between these parameters became apparent after averaging over the cohort. Spearman’s ρ between the original and predicted WT maps was 0.21 ± 0.22 (p < 0.001). Conclusions With a combination of bootstrapping and cohort-averaging methods, 3D WT maps can be predicted from the individual 3D WSS and diameter maps. The methodology may help to elucidate pathological processes involving WSS in carotid atherosclerosis. Electronic supplementary material The online version of this article (10.1186/s41747-018-0058-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Pim van Ooij
- Department of Radiology & Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.
| | - Merih Cibis
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, the Netherlands
| | - Ethan M Rowland
- Departments of Bioengineering, Imperial College London, London, UK
| | - Meike W Vernooij
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, the Netherlands.,Department of Epidemiology, Erasmus MC, Rotterdam, the Netherlands
| | - Aad van der Lugt
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, the Netherlands
| | - Peter D Weinberg
- Departments of Bioengineering, Imperial College London, London, UK
| | - Jolanda J Wentzel
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, the Netherlands
| | - Aart J Nederveen
- Department of Radiology & Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
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Callaghan FM, Grieve SM. Normal patterns of thoracic aortic wall shear stress measured using four-dimensional flow MRI in a large population. Am J Physiol Heart Circ Physiol 2018; 315:H1174-H1181. [PMID: 30028202 DOI: 10.1152/ajpheart.00017.2018] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Wall shear stress (WSS) plays a governing role in vascular remodeling and a pathogenic role in vessel wall diseases. However, little is known of the normal WSS patterns in the aorta as there is currently no practical means to routinely measure WSS and no normal ranges derived from population data exist. WSS measurements were made on the aorta of 224 subjects with normal anatomy using four-dimensional flow MRI with multiple encoding velocities and an optimized postprocessing routine. The spatial and temporal variation in WSS and oscillatory shear index was analyzed using a flat map representation of the unfolded aorta. The influence of aortic shape and velocity on WSS was evaluated using regression analysis. WSS in the thoracic aorta is dominated by axial flow. Average peak systolic WSS was 1.79 ± 0.71 Pa in the aortic arch and was significantly higher at 2.23 ± 1.04 Pa in the descending aorta, with a strong negative correlation with advancing age. The spatial distribution of WSS is highly heterogeneous, with a localized region of elevated WSS along the length of the anterior wall seen across all individuals. Our data demonstrate that accurate four-dimensional flow-derived WSS measurement is feasible, and we further provide a standardized parametric approach for presentation and analysis. We present a normal range for WSS across the lifespan, demonstrating a decrease in WSS with advancing age as well as illustrating the high degree of spatial and temporal variation. NEW & NOTEWORTHY With the use of four-dimensional flow MRI and postprocessing, accurate direct measurement of wall shear stress (WSS) was performed in a population of normal thoracic aortas ( n = 224). WSS was higher in the descending aorta compared with the aortic arch and decreased with age. A heterogeneous pattern of elevated WSS along the length of the aorta anterior wall was consistent across the population. This work provides normal data across the adult age range, permitting comparison with pathology.
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Affiliation(s)
- Fraser M Callaghan
- Sydney Translational Imaging Laboratory, Heart Research Institute, Charles Perkins Centre, University of Sydney , Sydney, New South Wales , Australia.,Sydney Medical School, University of Sydney, Camperdown, New South Wales , Australia
| | - Stuart M Grieve
- Sydney Translational Imaging Laboratory, Heart Research Institute, Charles Perkins Centre, University of Sydney , Sydney, New South Wales , Australia.,Sydney Medical School, University of Sydney, Camperdown, New South Wales , Australia.,Department of Radiology, Royal Prince Alfred Hospital, Camperdown, New South Wales , Australia.,Macquarie Medical Imaging, Macquarie University Hospital, Macquarie, New South Wales , Australia.,Sydney Adventist Hospital, Wahroonga, New South Wales , Australia
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34
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Dai Y, Lv P, Javadzadegan A, Tang X, Qian Y, Lin J. Hemodynamic analysis of carotid artery after endarterectomy: a preliminary and quantitative imaging study based on computational fluid dynamics and magnetic resonance angiography. Quant Imaging Med Surg 2018; 8:399-409. [PMID: 29928605 DOI: 10.21037/qims.2018.05.02] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background The carotid blood flow following carotid endarterectomy (CEA) is not fully understood. Computational fluid dynamics (CFD) is a promising method to study blood flow. This study is to investigate local hemodynamic characteristics after CEA via the use of unenhanced magnetic resonance angiography (MRA) and CFD. Methods Eight carotid arteries with atherosclerosis and sixteen normal carotid arteries were included in this study. Time-of-flight (TOF) and phase contrast (PC) MRA were applied for the measurement of three-dimensional artery geometries and velocity profile under CFD simulation. The hemodynamic parameters of the proximal internal carotid artery (ICA) including velocity, ICA/common carotid artery (CCA) velocity ratio, mean, maximum, minimum and gradient of wall shear stress (WSSmean, WSSmax, WSSmin and WSSG) were calculated before and after CEA. Morphologic characteristics of the carotid including bifurcation angle, tortuosity and planarity were also analyzed. Results Compared with pre-CEA, there was a significant reduction in post-CEA velocity, WSSmax, WSSmean, and WSSG, by 87.24%±13.38%, 86.86%±14.97%, 57.32%±56.71% and 69.74%±37.03% respectively, whereas WSSmin was almost unchanged. ICA/ CCA velocity ratios increased significantly after CEA. We also found that the post-CEA flow conditions were positively remodelled to approximate the conditions in normal arteries. The correlation between PC-MRA and CFD was excellent for the measurement of maximum velocity at the external carotid artery (r=0.846). Conclusions Our preliminary results indicated that major flow dynamics were restored shortly following CEA, and CFD based on MRA measurements could be useful for quantitative evaluation of hemodynamic outcomes after CEA.
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Affiliation(s)
- Yuanyuan Dai
- Department of Radiology, Zhongshan Hospital of Fudan University and Shanghai Institute of Medical Imaging, Shanghai 200032, China.,Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Peng Lv
- Department of Radiology, Zhongshan Hospital of Fudan University and Shanghai Institute of Medical Imaging, Shanghai 200032, China
| | - Ashkan Javadzadegan
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Xiao Tang
- Department of Vascular Surgery, Zhongshan Hospital of Fudan University, Shanghai 200032, China
| | - Yi Qian
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Jiang Lin
- Department of Radiology, Zhongshan Hospital of Fudan University and Shanghai Institute of Medical Imaging, Shanghai 200032, China
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Retrospective Study of Hemodynamic Changes Before and After Carotid Stenosis Formation by Vessel Surface Repairing. Sci Rep 2018; 8:5493. [PMID: 29615730 PMCID: PMC5883012 DOI: 10.1038/s41598-018-23842-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 03/13/2018] [Indexed: 12/28/2022] Open
Abstract
Prospective observation of hemodynamic changes before and after the formation of atherosclerotic stenosis in the carotid artery is difficult. Thus, a vessel surface repairing method was used for retrospective hemodynamic study before and after atherosclerotic stenosis formation in carotid artery. The three-dimensional geometry of sixteen sinus atherosclerotic stenosis carotid arteries were repaired and restored as normal arteries. Computational fluid dynamics analysis was performed to estimate wall shear stress (WSS), velocity and vortex in atherosclerosis-free areas and sinus in stenosis-repaired carotid artery. The analysis was also performed in the stenotic segment and upstream and downstream of stenosis in stenotic carotid artery. Compared to the atherosclerosis-free areas in stenosis-repaired carotid artery, sinus presented significantly lower WSS (P < 0.05), lower velocity (P < 0.05) and apparent vortex. Compared to the sinus, the WSS in the upstream of stenosis was lower (P < 0.05), while in the downstream area was similar (P = 0.87), both upstream and downstream of stenosis demonstrated similar velocity to sinus (P = 0.76 and P = 0.36, respectively) and apparent vortex. Atherosclerosis-prone areas including normal carotid sinus and upstream and downstream of stenosis in stenotic carotid artery were subjected to lower WSS and velocity as well as apparent vortex, thereby might be associated with the formation and progress of atherosclerosis.
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36
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Morbiducci U, Kok AM, Kwak BR, Stone PH, Steinman DA, Wentzel JJ. Atherosclerosis at arterial bifurcations: evidence for the role of haemodynamics and geometry. Thromb Haemost 2018; 115:484-92. [DOI: 10.1160/th15-07-0597] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 11/13/2015] [Indexed: 11/05/2022]
Abstract
SummaryAtherosclerotic plaques are found at distinct locations in the arterial system, despite the exposure to systemic risk factors of the entire vascular tree. From the study of arterial bifurcation regions, emerges ample evidence that haemodynamics are involved in the local onset and progression of the atherosclerotic disease. This observed co-localisation of disturbed flow regions and lesion prevalence at geometrically predisposed districts such as arterial bifurcations has led to the formulation of a ‘haemodynamic hypothesis’, that in this review is grounded to the most current research concerning localising factors of vascular disease. In particular, this review focuses on carotid and coronary bifurcations because of their primary relevance to stroke and heart attack. We highlight reported relationships between atherosclerotic plaque location, progression and composition, and fluid forces at vessel’s wall, in particular shear stress and its ‘easier-tomeasure’ surrogates, i.e. vascular geometric attributes (because geometry shapes the flow) and intravascular flow features (because they mediate disturbed shear stress), in order to give more insight in plaque initiation and destabilisation. Analogous to Virchow’s triad for thrombosis, atherosclerosis must be thought of as subject to a triad of, and especially interactions among, haemodynamic forces, systemic risk factors, and the biological response of the wall.
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Pagé G, Bettoni J, Salsac AV, Balédent O. Influence of principal component analysis acceleration factor on velocity measurement in 2D and 4D PC-MRI. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2018; 31:469-481. [PMID: 29357015 DOI: 10.1007/s10334-018-0673-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/28/2017] [Accepted: 01/03/2018] [Indexed: 11/24/2022]
Abstract
OBJECTIVE The objective of the study was to determine how to optimize 2D and 4D phase-contrast magnetic resonance imaging (PC-MRI) acquisitions to acquire flow velocities in millimetric vessels. In particular, we search for the best compromise between acquisition time and accuracy and assess the influence of the principal component analysis (PCA). MATERIALS AND METHODS 2D and 4D PC-MRI measurements are conducted within two in vitro vessel phantoms: a Y-bifurcation phantom, the branches of which range from 2 to 5 mm in diameter, and a physiological subject-specific phantom of the carotid bifurcation. The same sequences are applied in vivo in carotid vasculature. RESULTS For a vessel oriented in the axial direction, both 2D and axial 4D PC-MRI provided accuracy measurements regardless of the k-t PCA factor, while the acquisition time is reduced by a factor 6 for k-t PCA maximum value. The in vivo measurements show that the proposed sequences are adequate to acquire 2D and 4D velocity fields in millimetric vessels and with clinically realistic time durations. CONCLUSION The study shows the feasibility of conducting fast, high-resolution PC-MRI flow measurements in millimetric vessels and that it is worth maximizing the k-t PCA factor to reduce the acquisition time in the case of 2D and 4D axial acquisitions.
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Affiliation(s)
- Gwenaël Pagé
- BioFlow Image, University Hospital of Amiens Picardy, Université de Picardie Jules Verne, Avenue Rene Laennec, Salouël, 80480, Amiens, France.
| | - Jérémie Bettoni
- Maxillo-Facial Surgery, University Hospital of Amiens-Picardie, Amiens, France
| | - Anne-Virginie Salsac
- Biomechanics and Bioengineering Laboratory (UMR CNRS 7338), Sorbonne Universités, Université de Technologie de Compiègne-CNRS, Compiègne, France
| | - Olivier Balédent
- BioFlow Image, University Hospital of Amiens Picardy, Université de Picardie Jules Verne, Avenue Rene Laennec, Salouël, 80480, Amiens, France.,Laboratory of Image Processing, University Hospital of Amiens-Picardie, Amiens, France
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38
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Sindeev S, Arnold PG, Frolov S, Prothmann S, Liepsch D, Balasso A, Berg P, Kaczmarz S, Kirschke JS. Phase-contrast MRI versus numerical simulation to quantify hemodynamical changes in cerebral aneurysms after flow diverter treatment. PLoS One 2018; 13:e0190696. [PMID: 29304062 PMCID: PMC5755883 DOI: 10.1371/journal.pone.0190696] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 12/19/2017] [Indexed: 02/05/2023] Open
Abstract
Cerebral aneurysms are a major risk factor for intracranial bleeding with devastating consequences for the patient. One recently established treatment is the implantation of flow-diverters (FD). Methods to predict their treatment success before or directly after implantation are not well investigated yet. The aim of this work was to quantitatively study hemodynamic parameters in patient-specific models of treated cerebral aneurysms and its correlation with the clinical outcome. Hemodynamics were evaluated using both computational fluid dynamics (CFD) and phase contrast (PC) MRI. CFD simulations and in vitro MRI measurements were done under similar flow conditions and results of both methods were comparatively analyzed. For preoperative and postoperative distribution of hemodynamic parameters, CFD simulations and PC-MRI velocity measurements showed similar results. In both cases where no occlusion of the aneurysm was observed after six months, a flow reduction of about 30-50% was found, while in the clinically successful case with complete occlusion of the aneurysm after 6 months, the flow reduction was about 80%. No vortex was observed in any of the three models after treatment. The results are in agreement with recent studies suggesting that CFD simulations can predict post-treatment aneurysm flow alteration already before implantation of a FD and PC-MRI could validate the predicted hemodynamic changes right after implantation of a FD.
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Affiliation(s)
- Sergey Sindeev
- Department of Biomedical Engineering, Tambov State Technical University, Tambov, Russia
- * E-mail:
| | - Philipp Georg Arnold
- Department of Neuroradiology, Klinikum rechts der Isar of Technical University of Munich, Munich, Germany
| | - Sergey Frolov
- Department of Biomedical Engineering, Tambov State Technical University, Tambov, Russia
| | - Sascha Prothmann
- Department of Neuroradiology, Klinikum rechts der Isar of Technical University of Munich, Munich, Germany
| | - Dieter Liepsch
- Department of Building Services Engineering, Chemical Engineering for Paper and Packaging, Print and Media Technologies, Munich University of Applied Sciences, Munich, Germany
| | - Andrea Balasso
- Department of Earth and Environmental Sciences, Ludwig-Maximilian-University of Munich, Munich, Germany
| | - Philipp Berg
- Department of Fluid Dynamics and Technical Flows, University of Magdeburg, Magdeburg, Germany
| | - Stephan Kaczmarz
- Department of Neuroradiology, Klinikum rechts der Isar of Technical University of Munich, Munich, Germany
| | - Jan Stefan Kirschke
- Department of Neuroradiology, Klinikum rechts der Isar of Technical University of Munich, Munich, Germany
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Szajer J, Ho-Shon K. A comparison of 4D flow MRI-derived wall shear stress with computational fluid dynamics methods for intracranial aneurysms and carotid bifurcations - A review. Magn Reson Imaging 2017; 48:62-69. [PMID: 29223732 DOI: 10.1016/j.mri.2017.12.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 11/23/2017] [Accepted: 12/03/2017] [Indexed: 12/25/2022]
Abstract
BACKGROUND 4D flow MRI is a relatively quick method for obtaining wall shear stress (WSS) in vivo, a hemodynamic parameter which has shown promise in risk stratification for rupture of cerebrovascular diseases such as intracranial aneurysms and atherosclerotic plaques. The accuracy of such measurements is still largely unknown. OBJECTIVE To quantify the accuracy of 4D flow MRI-derived wall shear stress values for intracranial aneurysms and carotid bifurcations. METHOD We performed a review of all original research articles which compared the magnitudes of WSS derived from 4D flow MRI with corresponding values derived from computational fluid dynamics (CFD) within both intracranial aneurysms and carotid bifurcations. RESULT For intracranial aneurysms and carotid bifurcations, 4D flow MRI-derived WSS estimations are generally lower in magnitude compared to WSS derived by CFD methods. These differences are more pronounced in regions of higher WSS. However, the relative distributions of WSS derived from both methods are reasonably similar. CONCLUSION Pooled analysis suggests that WSS magnitudes obtained by 4D flow MRI are underestimated, while the relative distribution is reasonably accurate, the latter being an important factor for determining the natural history of intracranial aneurysms and other cerebrovascular diseases. 4D flow MRI shows enormous potential in providing new risk stratification parameters which could have significant impact on individualized treatment decisions and improved patient outcomes.
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Affiliation(s)
- Jeremy Szajer
- Faculty of Medicine and Health Sciences, Macquarie University, Macquarie Park, Australia.
| | - Kevin Ho-Shon
- Faculty of Medicine and Health Sciences, Macquarie University, Macquarie Park, Australia
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40
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Coolen BF, Calcagno C, van Ooij P, Fayad ZA, Strijkers GJ, Nederveen AJ. Vessel wall characterization using quantitative MRI: what's in a number? MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2017; 31:201-222. [PMID: 28808823 PMCID: PMC5813061 DOI: 10.1007/s10334-017-0644-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 07/04/2017] [Accepted: 07/18/2017] [Indexed: 12/15/2022]
Abstract
The past decade has witnessed the rapid development of new MRI technology for vessel wall imaging. Today, with advances in MRI hardware and pulse sequences, quantitative MRI of the vessel wall represents a real alternative to conventional qualitative imaging, which is hindered by significant intra- and inter-observer variability. Quantitative MRI can measure several important morphological and functional characteristics of the vessel wall. This review provides a detailed introduction to novel quantitative MRI methods for measuring vessel wall dimensions, plaque composition and permeability, endothelial shear stress and wall stiffness. Together, these methods show the versatility of non-invasive quantitative MRI for probing vascular disease at several stages. These quantitative MRI biomarkers can play an important role in the context of both treatment response monitoring and risk prediction. Given the rapid developments in scan acceleration techniques and novel image reconstruction, we foresee the possibility of integrating the acquisition of multiple quantitative vessel wall parameters within a single scan session.
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Affiliation(s)
- Bram F Coolen
- Department of Biomedical Engineering and Physics, Academic Medical Center, PO BOX 22660, 1100 DD, Amsterdam, The Netherlands. .,Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands.
| | - Claudia Calcagno
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Pim van Ooij
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Zahi A Fayad
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Gustav J Strijkers
- Department of Biomedical Engineering and Physics, Academic Medical Center, PO BOX 22660, 1100 DD, Amsterdam, The Netherlands
| | - Aart J Nederveen
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands
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41
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Cibis M, Potters WV, Gijsen FJ, Marquering H, van Ooij P, vanBavel E, Wentzel JJ, Nederveen AJ. The Effect of Spatial and Temporal Resolution of Cine Phase Contrast MRI on Wall Shear Stress and Oscillatory Shear Index Assessment. PLoS One 2016; 11:e0163316. [PMID: 27669568 PMCID: PMC5036833 DOI: 10.1371/journal.pone.0163316] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 09/07/2016] [Indexed: 11/21/2022] Open
Abstract
Introduction Wall shear stress (WSS) and oscillatory shear index (OSI) are associated with atherosclerotic disease. Both parameters are derived from blood velocities, which can be measured with phase-contrast MRI (PC-MRI). Limitations in spatiotemporal resolution of PC-MRI are known to affect these measurements. Our aim was to investigate the effect of spatiotemporal resolution using a carotid artery phantom. Methods A carotid artery phantom was connected to a flow set-up supplying pulsatile flow. MRI measurement planes were placed at the common carotid artery (CCA) and internal carotid artery (ICA). Two-dimensional PC-MRI measurements were performed with thirty different spatiotemporal resolution settings. The MRI flow measurement was validated with ultrasound probe measurements. Mean flow, peak flow, flow waveform, WSS and OSI were compared for these spatiotemporal resolutions using regression analysis. The slopes of the regression lines were reported in %/mm and %/100ms. The distribution of low and high WSS and OSI was compared between different spatiotemporal resolutions. Results The mean PC-MRI CCA flow (2.5±0.2mL/s) agreed with the ultrasound probe measurements (2.7±0.02mL/s). Mean flow (mL/s) depended only on spatial resolution (CCA:-13%/mm, ICA:-49%/mm). Peak flow (mL/s) depended on both spatial (CCA:-13%/mm, ICA:-17%/mm) and temporal resolution (CCA:-19%/100ms, ICA:-24%/100ms). Mean WSS (Pa) was in inverse relationship only with spatial resolution (CCA:-19%/mm, ICA:-33%/mm). OSI was dependent on spatial resolution for CCA (-26%/mm) and temporal resolution for ICA (-16%/100ms). The regions of low and high WSS and OSI matched for most of the spatiotemporal resolutions (CCA:30/30, ICA:28/30 cases for WSS; CCA:23/30, ICA:29/30 cases for OSI). Conclusion We show that both mean flow and mean WSS are independent of temporal resolution. Peak flow and OSI are dependent on both spatial and temporal resolution. However, the magnitude of mean and peak flow, WSS and OSI, and the spatial distribution of OSI and WSS did not exhibit a strong dependency on spatiotemporal resolution.
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Affiliation(s)
- Merih Cibis
- Biomedical Engineering Department, Erasmus MC, Rotterdam, The Netherlands
- * E-mail:
| | - Wouter V. Potters
- Radiology Department, Academic Medical Center (AMC), Amsterdam, The Netherlands
| | - Frank J. Gijsen
- Biomedical Engineering Department, Erasmus MC, Rotterdam, The Netherlands
| | - Henk Marquering
- Radiology Department, Academic Medical Center (AMC), Amsterdam, The Netherlands
- Biomedical Engineering and Physics Department, AMC, Amsterdam, The Netherlands
| | - Pim van Ooij
- Radiology Department, Academic Medical Center (AMC), Amsterdam, The Netherlands
| | - Ed vanBavel
- Biomedical Engineering and Physics Department, AMC, Amsterdam, The Netherlands
| | - Jolanda J. Wentzel
- Biomedical Engineering Department, Erasmus MC, Rotterdam, The Netherlands
| | - Aart J. Nederveen
- Radiology Department, Academic Medical Center (AMC), Amsterdam, The Netherlands
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High shear stress relates to intraplaque haemorrhage in asymptomatic carotid plaques. Atherosclerosis 2016; 251:348-354. [PMID: 27263078 DOI: 10.1016/j.atherosclerosis.2016.05.018] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 04/29/2016] [Accepted: 05/07/2016] [Indexed: 02/02/2023]
Abstract
BACKGROUND AND AIMS Carotid artery plaques with vulnerable plaque components are related to a higher risk of cerebrovascular accidents. It is unknown which factors drive vulnerable plaque development. Shear stress, the frictional force of blood at the vessel wall, is known to influence plaque formation. We evaluated the association between shear stress and plaque components (intraplaque haemorrhage (IPH), lipid rich necrotic core (LRNC) and/or calcifications) in relatively small carotid artery plaques in asymptomatic persons. METHODS Participants (n = 74) from the population-based Rotterdam Study, all with carotid atherosclerosis assessed on ultrasound, underwent carotid MRI. Multiple MRI sequences were used to evaluate the presence of IPH, LRNC and/or calcifications in plaques in the carotid arteries. Images were automatically segmented for lumen and outer wall to obtain a 3D reconstruction of the carotid bifurcation. These reconstructions were used to calculate minimum, mean and maximum shear stresses by applying computational fluid dynamics with subject-specific inflow conditions. Associations between shear stress measures and plaque composition were studied using generalized estimating equations analysis, adjusting for age, sex and carotid wall thickness. RESULTS The study group consisted of 93 atherosclerotic carotid arteries of 74 participants. In plaques with higher maximum shear stresses, IPH was more often present (OR per unit increase in maximum shear stress (log transformed) = 12.14; p = 0.001). Higher maximum shear stress was also significantly associated with the presence of calcifications (OR = 4.28; p = 0.015). CONCLUSIONS Higher maximum shear stress is associated with intraplaque haemorrhage and calcifications.
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van Ooij P, Garcia J, Potters WV, Malaisrie SC, Collins JD, Carr JC, Markl M, Barker AJ. Age-related changes in aortic 3D blood flow velocities and wall shear stress: Implications for the identification of altered hemodynamics in patients with aortic valve disease. J Magn Reson Imaging 2016; 43:1239-49. [PMID: 26477691 PMCID: PMC4836971 DOI: 10.1002/jmri.25081] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/06/2015] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To investigate age-related changes in peak systolic aortic 3D velocity and wall shear stress (WSS) in healthy controls and to investigate the importance of age-matching for 3D mapping of abnormal aortic hemodynamics in bicuspid aortic valve disease (BAV). MATERIALS AND METHODS 4D flow MRI (fields strengths = 1.5-3T; resolution = 2.2-3.9 × 1.7-2.6 × 2.2-4.0 mm(3) ; Venc = 150-250 cm/s; TE/TR/FA = 2.3-2.8/4.7-5.4msec/7-15°) was performed in 56 controls (age range: 19-78 years) and in two BAV patient groups each consisting of 10 subjects (group 1: 20-29 years, group 2: 52-57 years). Heat maps showing abnormal 3D velocity and WSS were created for the BAV patients by comparison with an age-matched and with an unmatched control group. The fraction of the aorta exposed to abnormal velocity/WSS was calculated relative to the total aortic volume/surface. RESULTS Significant inverse relationships between age and healthy velocity/WSS were found (R(2) = 0.32/0.39, P < 0.001). For BAV group 1, abnormally elevated velocity/WSS was overestimated when compared with older controls (51-60 years) than when correctly age-matched (∼25 ± 14% vs. ∼8 ± 5%). For BAV group 2, abnormally decreased velocity/WSS was overestimated when compared with younger controls (21-30 years) than when correctly age-matched (∼9 ± 7% vs. 1 ± 1%). CONCLUSION Significant correlations exist between age and peak systolic velocity and WSS. Therefore, robust age-matching is important when creating abnormal 3D aortic velocity and WSS maps for patients with BAV.
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Affiliation(s)
- Pim van Ooij
- Department of Radiology, Northwestern University, Chicago, IL, USA
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Julio Garcia
- Department of Radiology, Northwestern University, Chicago, IL, USA
| | - Wouter V. Potters
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands
| | | | | | - James C. Carr
- Department of Radiology, Northwestern University, Chicago, IL, USA
| | - Michael Markl
- Department of Radiology, Northwestern University, Chicago, IL, USA
- Department of Biomedical Engineering, Northwestern University, Chicago, IL, USA
| | - Alex J. Barker
- Department of Radiology, Northwestern University, Chicago, IL, USA
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Gharahi H, Zambrano BA, Zhu DC, DeMarco JK, Baek S. Computational fluid dynamic simulation of human carotid artery bifurcation based on anatomy and volumetric blood flow rate measured with magnetic resonance imaging. INTERNATIONAL JOURNAL OF ADVANCES IN ENGINEERING SCIENCES AND APPLIED MATHEMATICS 2016; 8:40-60. [PMID: 27546999 PMCID: PMC4987097 DOI: 10.1007/s12572-016-0161-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Blood flow patterns and local hemodynamic parameters have been widely associated with the onset and progression of atherosclerosis in the carotid artery. Assessment of these parameters can be performed noninvasively using cine phase-contrast (PC) magnetic resonance imaging (MRI). In addition, in the last two decades, computational fluid dynamics (CFD) simulation in three dimensional models derived from anatomic medical images has been employed to investigate the blood flow in the carotid artery. This study developed a workflow of a subject-specific CFD analysis using MRI to enhance estimating hemodynamics of the carotid artery. Time-of-flight (TOF) MRI scans were used to construct three-dimensional computational models. PC-MRI measurements were utilized to impose the boundary condition at the inlet and a 0-dimensional lumped parameter model was employed for the outflow boundary condition. The choice of different viscosity models of blood flow as a source of uncertainty was studied, by means of the axial velocity, wall shear stress, and oscillatory shear index. The sequence of workflow in CFD analysis was optimized for a healthy subject using PC-MRI. Then, a patient with carotid artery stenosis and its hemodynamic parameters were examined. The simulations indicated that the lumped parameter model used at the outlet gives physiologically reasonable values of hemodynamic parameters. Moreover, the dependence of hemodynamics parameters on the viscosity models was observed to vary for different geometries. Other factors, however, may be required for a more accurate CFD analysis, such as the segmentation and smoothness of the geometrical model, mechanical properties of the artery's wall, and the prescribed velocity profile at the inlet.
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Affiliation(s)
- Hamidreza Gharahi
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan, USA
| | - Byron A. Zambrano
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan, USA
| | - David C. Zhu
- Department of Radiology, Michigan State University, East Lansing, Michigan, USA
- Department of Psychology, Michigan State University, East Lansing, Michigan, USA
- Cognitive Imaging Research Center, Michigan State University, East Lansing, Michigan, USA
| | - J. Kevin DeMarco
- Department of Radiology, Michigan State University, East Lansing, Michigan, USA
| | - Seungik Baek
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan, USA
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Cibis M, Potters WV, Selwaness M, Gijsen FJ, Franco OH, Arias Lorza AM, de Bruijne M, Hofman A, van der Lugt A, Nederveen AJ, Wentzel JJ. Relation between wall shear stress and carotid artery wall thickening MRI versus CFD. J Biomech 2016; 49:735-741. [PMID: 26897648 DOI: 10.1016/j.jbiomech.2016.02.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 12/24/2015] [Accepted: 02/03/2016] [Indexed: 10/22/2022]
Abstract
Wall shear stress (WSS), a parameter associated with endothelial function, is calculated by computational fluid dynamics (CFD) or phase-contrast (PC) MRI measurements. Although CFD is common in WSS (WSSCFD) calculations, PC-MRI-based WSS (WSSMRI) is more favorable in population studies; since it is straightforward and less time consuming. However, it is not clear if WSSMRI and WSSCFD show similar associations with vascular pathology. Our aim was to test the associations between wall thickness (WT) of the carotid arteries and WSSMRI and WSSCFD. The subjects (n=14) with an asymptomatic carotid plaque who underwent MRI scans two times within 4 years of time were selected from the Rotterdam Study. We compared WSSCFD and WSSMRI at baseline and follow-up. Baseline WSSMRI and WSSCFD values were divided into 3 categories representing low, medium and high WSS tertiles. WT of each tertile was compared by a one-way ANOVA test. The WSSMRI and WSSCFD were 0.50±0.13Pa and 0.73±0.25Pa at baseline. Although WSSMRI was underestimated, a significant regression was found between WSSMRI and WSSCFD (r(2)=0.71). No significant difference was found between baseline and follow-up WSS by CFD and MRI-based calculations. The WT at baseline was 1.36±0.16mm and did not change over time. The WT was 1.55±0.21mm in low, 1.33±0.20mm in medium and 1.21±0.21mm in the high WSSMRI tertiles. Similarly, the WT was 1.49±0.21mm in low, 1.33±0.20mm in medium and 1.26±0.21mm in high WSSCFD tertiles. We found that WSSMRI and WSSCFD were inversely related with WT. WSSMRI and WSSCFD patterns were similar although MRI-based calculations underestimated WSS.
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Affiliation(s)
- Merih Cibis
- Erasmus MC, Biomedical Engineering Department, Rotterdam, The Netherlands
| | | | | | - Frank J Gijsen
- Erasmus MC, Biomedical Engineering Department, Rotterdam, The Netherlands
| | - Oscar H Franco
- Erasmus MC, Department of Epidemiology, Rotterdam, The Netherlands
| | - Andres M Arias Lorza
- Erasmus MC, Biomedical Imaging Group Rotterdam, Departments of Radiology and Medical Informatics, Rotterdam, The Netherlands
| | - Marleen de Bruijne
- Erasmus MC, Biomedical Imaging Group Rotterdam, Departments of Radiology and Medical Informatics, Rotterdam, The Netherlands; Department of Computer Science, University of Copenhagen, Denmark
| | - Albert Hofman
- Erasmus MC, Department of Epidemiology, Rotterdam, The Netherlands
| | - Aad van der Lugt
- Erasmus MC, Department of Epidemiology, Rotterdam, The Netherlands
| | | | - Jolanda J Wentzel
- Erasmus MC, Biomedical Engineering Department, Rotterdam, The Netherlands.
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Speelman L, Teng Z, Nederveen AJ, van der Lugt A, Gillard JH. MRI-based biomechanical parameters for carotid artery plaque vulnerability assessment. Thromb Haemost 2016; 115:493-500. [PMID: 26791734 DOI: 10.1160/th15-09-0712] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 12/13/2015] [Indexed: 12/18/2022]
Abstract
Carotid atherosclerotic plaques are a major cause of ischaemic stroke. The biomechanical environment to which the arterial wall and plaque is subjected to plays an important role in the initiation, progression and rupture of carotid plaques. MRI is frequently used to characterize the morphology of a carotid plaque, but new developments in MRI enable more functional assessment of carotid plaques. In this review, MRI based biomechanical parameters are evaluated on their current status, clinical applicability, and future developments. Blood flow related biomechanical parameters, including endothelial wall shear stress and oscillatory shear index, have been shown to be related to plaque formation. Deriving these parameters directly from MRI flow measurements is feasible and has great potential for future carotid plaque development prediction. Blood pressure induced stresses in a plaque may exceed the tissue strength, potentially leading to plaque rupture. Multi-contrast MRI based stress calculations in combination with tissue strength assessment based on MRI inflammation imaging may provide a plaque stress-strength balance that can be used to assess the plaque rupture risk potential. Direct plaque strain analysis based on dynamic MRI is already able to identify local plaque displacement during the cardiac cycle. However, clinical evidence linking MRI strain to plaque vulnerability is still lacking. MRI based biomechanical parameters may lead to improved assessment of carotid plaque development and rupture risk. However, better MRI systems and faster sequences are required to improve the spatial and temporal resolution, as well as increase the image contrast and signal-to-noise ratio.
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Affiliation(s)
- Lambert Speelman
- Dr. Lambert Speelman, Department of Biomedical Engineering, Ee 23.38B, P.O Box 2040, 3000 CA Rotterdam, the Netherlands, Tel.: +31 10 70 44039, Fax: +31 10 70 44720, E-mail:
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Assessment of Hemodynamic Conditions in the Aorta Following Root Replacement with Composite Valve-Conduit Graft. Ann Biomed Eng 2015; 44:1392-404. [PMID: 26369636 DOI: 10.1007/s10439-015-1453-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 09/07/2015] [Indexed: 10/23/2022]
Abstract
This paper presents the analysis of detailed hemodynamics in the aortas of four patients following replacement with a composite bio-prosthetic valve-conduit. Magnetic resonance image-based computational models were set up for each patient with boundary conditions comprising subject-specific three-dimensional inflow velocity profiles at the aortic root and central pressure waveform at the model outlet. Two normal subjects were also included for comparison. The purpose of the study was to investigate the effects of the valve-conduit on flow in the proximal and distal aorta. The results suggested that following the composite valve-conduit implantation, the vortical flow structure and hemodynamic parameters in the aorta were altered, with slightly reduced helical flow index, elevated wall shear stress and higher non-uniformity in wall shear compared to normal aortas. Inter-individual analysis revealed different hemodynamic conditions among the patients depending on the conduit configuration in the ascending aorta, which is a key factor in determining post-operative aortic flow. Introducing a natural curvature in the conduit to create a smooth transition between the conduit and native aorta may help prevent the occurrence of retrograde and recirculating flow in the aortic arch, which is particularly important when a large portion or the entire ascending aorta needs to be replaced.
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Singh N, Moody AR, Roifman I, Bluemke DA, Zavodni AEH. Advanced MRI for carotid plaque imaging. Int J Cardiovasc Imaging 2015; 32:83-9. [PMID: 26293362 PMCID: PMC4706840 DOI: 10.1007/s10554-015-0743-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 08/13/2015] [Indexed: 10/28/2022]
Abstract
Atherosclerosis is the ubiquitous underling pathological process that manifests in heart attack and stroke, cumulating in the death of one in three North American adults. High-resolution magnetic resonance imaging (MRI) is able to delineate atherosclerotic plaque components and total plaque burden within the carotid arteries. Using dedicated hardware, high resolution images can be obtained. Combining pre- and post-contrast T1, T2, proton-density, and magnetization-prepared rapid acquisition gradient echo weighted fat-saturation imaging, plaque components can be defined. Post-processing software allows for semi- and fully automated quantitative analysis. Imaging correlation with surgical specimens suggests that this technique accurately differentiates plaque features. Total plaque burden and specific plaque components such as a thin fibrous cap, large fatty or necrotic core and intraplaque hemorrhage are accepted markers of neuroischemic events. Given the systemic nature of atherosclerosis, emerging science suggests that the presence of carotid plaque is also an indicator of coronary artery plaque burden, although the preliminary data primarily involves patients with stable coronary disease. While the availability and cost-effectiveness of MRI will ultimately be important determinants of whether carotid MRI is adopted clinically in cardiovascular risk assessment, the high accuracy and reliability of this technique suggests that it has potential as an imaging biomarker of future risk.
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Affiliation(s)
- Navneet Singh
- Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, 2075 Bayview Avenue, Room AG56b, Toronto, ON, M4N 3M5, Canada
| | - Alan R Moody
- Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, 2075 Bayview Avenue, Room AG56b, Toronto, ON, M4N 3M5, Canada
| | - Idan Roifman
- Division of Cardiology, Department of Internal Medicine, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada
| | - David A Bluemke
- Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Anna E H Zavodni
- Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, 2075 Bayview Avenue, Room AG56b, Toronto, ON, M4N 3M5, Canada.
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Cibis M, Jarvis K, Markl M, Rose M, Rigsby C, Barker AJ, Wentzel JJ. The effect of resolution on viscous dissipation measured with 4D flow MRI in patients with Fontan circulation: Evaluation using computational fluid dynamics. J Biomech 2015; 48:2984-9. [PMID: 26298492 DOI: 10.1016/j.jbiomech.2015.07.039] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 07/03/2015] [Accepted: 07/30/2015] [Indexed: 10/23/2022]
Abstract
Viscous dissipation inside Fontan circulation, a parameter associated with the exercise intolerance of Fontan patients, can be derived from computational fluid dynamics (CFD) or 4D flow MRI velocities. However, the impact of spatial resolution and measurement noise on the estimation of viscous dissipation is unclear. Our aim was to evaluate the influence of these parameters on viscous dissipation calculation. Six Fontan patients underwent whole heart 4D flow MRI. Subject-specific CFD simulations were performed. The CFD velocities were down-sampled to isotropic spatial resolutions of 0.5mm, 1mm, 2mm and to MRI resolution. Viscous dissipation was compared between (1) high resolution CFD velocities, (2) CFD velocities down-sampled to MRI resolution, (3) down-sampled CFD velocities with MRI mimicked noise levels, and (4) in-vivo 4D flow MRI velocities. Relative viscous dissipation between subjects was also calculated. 4D flow MRI velocities (15.6 ± 3.8 cm/s) were higher, although not significantly different than CFD velocities (13.8 ± 4.7 cm/s, p=0.16), down-sampled CFD velocities (12.3 ± 4.4 cm/s, p=0.06) and the down-sampled CFD velocities with noise (13.2 ± 4.2 cm/s, p=0.06). CFD-based viscous dissipation (0.81 ± 0.55 mW) was significantly higher than those based on down-sampled CFD (0.25 ± 0.19 mW, p=0.03), down-sampled CFD with noise (0.49 ± 0.26 mW, p=0.03) and 4D flow MRI (0.56 ± 0.28 mW, p=0.06). Nevertheless, relative viscous dissipation between different subjects was maintained irrespective of resolution and noise, suggesting that comparison of viscous dissipation between patients is still possible.
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Affiliation(s)
- Merih Cibis
- Biomedical Engineering, Erasmus Medical Center, Rotterdam, Netherlands.
| | - Kelly Jarvis
- Radiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States; Biomedical Engineering, Northwestern University, Chicago, IL, United States
| | - Michael Markl
- Radiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States; Biomedical Engineering, Northwestern University, Chicago, IL, United States
| | - Michael Rose
- Radiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States
| | - Cynthia Rigsby
- Radiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States; Medical Imaging, Ann & Robert H Lurie Children's Hospital of Chicago, Chicago, IL, United States
| | - Alex J Barker
- Radiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States
| | - Jolanda J Wentzel
- Biomedical Engineering, Erasmus Medical Center, Rotterdam, Netherlands
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50
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van Ooij P, Powell AL, Potters WV, Carr JC, Markl M, Barker AJ. Reproducibility and interobserver variability of systolic blood flow velocity and 3D wall shear stress derived from 4D flow MRI in the healthy aorta. J Magn Reson Imaging 2015; 43:236-48. [PMID: 26140480 DOI: 10.1002/jmri.24959] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 05/13/2015] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To investigate the reproducibility and interobserver variability of 3D aortic velocity vector fields and wall shear stress (WSS) averaged over five systolic timeframes derived from noncontrast 4D flow magnetic resonance imaging (MRI). MATERIALS AND METHODS Fourteen controls underwent test-retest 4D flow MRI examinations separated by 16 ± 3 days (resolution = 3.0-3.6 × 2.3-2.6 × 2.5-2.7 mm(3) ; TE/TR/FA = 2.5/4.9 msec/7°; Venc = 150 cm/s). Two observers segmented the aorta, and WSS was calculated for both series of scans and both segmentations. Test-retest and interobserver velocity and WSS vectors were compared on a voxel-by-voxel basis in the aorta and on a regional basis by subdividing the aortas in six segments. RESULTS Test-retest: voxel-by-voxel Bland-Altman analysis revealed small differences (-0.03/-0.02 m/s/Pa), limits of agreement (LOA) of 0.25 m/s/0.29 Pa, and coefficients of variation (CV) of 20% for velocity/WSS. Voxel-by-voxel orthogonal regression analysis showed moderate agreement (slope: 1.14/1.16, intraclass correlation coefficient [ICC]: 0.76/0.67 for velocity/WSS). The regional analysis revealed a CV of 9%/8% and ICC of 0.9/0.9 for velocity/WSS. Interobserver: voxel-by-voxel difference for WSS was 0, LOA: 0.17/0.19 Pa, CV: 12/13%, slope: 1.01/1.09, ICC: 0.87/0.85 for test/retest. The CV/ICC for WSS in the regional analysis was 4%/1.0 for test and 3%/1.0 for retest. CONCLUSION Systolic velocity and WSS derived from 4D flow MRI are reproducible between consecutive visits, with low interobserver variability in healthy volunteers.
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Affiliation(s)
- Pim van Ooij
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Alexander L Powell
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Wouter V Potters
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands
| | - James C Carr
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Michael Markl
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, Illinois, USA
| | - Alex J Barker
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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