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Mendieta JB, Fontanarosa D, Wang J, Paritala PK, Muller J, Lloyd T, Li Z. MRI-based mechanical analysis of carotid atherosclerotic plaque using a material-property-mapping approach: A material-property-mapping method for plaque stress analysis. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 231:107417. [PMID: 36827823 DOI: 10.1016/j.cmpb.2023.107417] [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: 11/07/2022] [Revised: 01/23/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND AND OBJECTIVE Atherosclerosis is a major underlying cause of cardiovascular conditions. In order to understand the biomechanics involved in the generation and rupture of atherosclerotic plaques, numerical analysis methods have been widely used. However, several factors limit the practical use of this information in a clinical setting. One of the key challenges in finite element analysis (FEA) is the reconstruction of the structure and the generation of a mesh. The complexity of the shapes associated with carotid plaques, including multiple components, makes the generation of meshes for biomechanical computation a difficult and in some cases, an impossible task. To address these challenges, in this study, we propose a novel material-property-mapping method for carotid atherosclerotic plaque stress analysis that aims to simplify the process. METHODS The different carotid plaque components were identified and segmented using magnetic resonance imaging (MRI). For the mapping method, this information was used in conjunction with an in-house code, which provided the coordinates for each pixel/voxel and tissue type within a predetermined region of interest. These coordinates were utilized to assign specific material properties to each element in the volume mesh which provides a region of transition. The proposed method was subsequently compared to the traditional method, which involves creating a composed mesh for the arterial wall and plaque components, based on its location and size. RESULTS The comparison between the proposed material-property-mapping method and the traditional method was performed in 2D, 3D structural-only, and fluid-structure interaction (FSI) simulations in terms of stress, wall shear stress (WSS), time-averaged WSS (TAWSS), and oscillatory shear index (OSI). The stress contours from both methods were found to be similar, although the proposed method tended to produce lower local maximum stress values. The WSS contours were also in agreement between the two methods. The velocity contours generated by the proposed method were verified against phase-contrast magnetic resonance imaging (MRI) measurements, for a higher level of confidence. CONCLUSION This study shows that a material-property-mapping method can effectively be used for analyzing the biomechanics of carotid plaques in a patient-specific manner. This approach has the potential to streamline the process of creating volume meshes for complex biological structures, such as carotid plaques, and to provide a more efficient and less labor-intensive method.
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Affiliation(s)
- Jessica Benitez Mendieta
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane 4000, Australia
| | - Davide Fontanarosa
- School of Clinical Sciences, Queensland University of Technology, Brisbane 4000, Australia
| | - Jiaqiu Wang
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane 4000, Australia
| | - Phani Kumari Paritala
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane 4000, Australia
| | - Juanita Muller
- Department of Vascular Surgery, Princess Alexandra Hospital, Brisbane 4102, Australia
| | - Thomas Lloyd
- Department of Radiology, Princess Alexandra Hospital, Brisbane 4102, Australia
| | - Zhiyong Li
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane 4000, Australia; Faculty of Sports Science, Ningbo University, Ningbo 315211, China.
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Wang J, Paritala PK, Mendieta JB, Komori Y, Raffel OC, Gu Y, Li Z. Optical coherence tomography-based patient-specific coronary artery reconstruction and fluid–structure interaction simulation. Biomech Model Mechanobiol 2019; 19:7-20. [DOI: 10.1007/s10237-019-01191-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 06/21/2019] [Indexed: 01/14/2023]
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Nieuwstadt HA, Fekkes S, Hansen HHG, de Korte CL, van der Lugt A, Wentzel JJ, van der Steen AFW, Gijsen FJH. Carotid plaque elasticity estimation using ultrasound elastography, MRI, and inverse FEA - A numerical feasibility study. Med Eng Phys 2015; 37:801-7. [PMID: 26130603 DOI: 10.1016/j.medengphy.2015.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 06/02/2015] [Accepted: 06/07/2015] [Indexed: 12/13/2022]
Abstract
The material properties of atherosclerotic plaques govern the biomechanical environment, which is associated with rupture-risk. We investigated the feasibility of noninvasively estimating carotid plaque component material properties through simulating ultrasound (US) elastography and in vivo magnetic resonance imaging (MRI), and solving the inverse problem with finite element analysis. 2D plaque models were derived from endarterectomy specimens of nine patients. Nonlinear neo-Hookean models (tissue elasticity C1) were assigned to fibrous intima, wall (i.e., media/adventitia), and lipid-rich necrotic core. Finite element analysis was used to simulate clinical cross-sectional US strain imaging. Computer-simulated, single-slice in vivo MR images were segmented by two MR readers. We investigated multiple scenarios for plaque model elasticity, and consistently found clear separations between estimated tissue elasticity values. The intima C1 (160 kPa scenario) was estimated as 125.8 ± 19.4 kPa (reader 1) and 128.9 ± 24.8 kPa (reader 2). The lipid-rich necrotic core C1 (5 kPa) was estimated as 5.6 ± 2.0 kPa (reader 1) and 8.5 ± 4.5 kPa (reader 2). A scenario with a stiffer wall yielded similar results, while realistic US strain noise and rotating the models had little influence, thus demonstrating robustness of the procedure. The promising findings of this computer-simulation study stimulate applying the proposed methodology in a clinical setting.
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Affiliation(s)
- H A Nieuwstadt
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, The Netherlands.
| | - S Fekkes
- Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - H H G Hansen
- Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - C L de Korte
- Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - A van der Lugt
- Department of Radiology, Erasmus MC, Rotterdam, The Netherlands
| | - J J Wentzel
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, The Netherlands
| | - A F W van der Steen
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, The Netherlands; Department of Imaging Science and Technology, Delft University of Technology, Delft, The Netherlands
| | - F J H Gijsen
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, The Netherlands.
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Nieuwstadt HA, Kassar ZAM, van der Lugt A, Breeuwer M, van der Steen AFW, Wentzel JJ, Gijsen FJH. A computer-simulation study on the effects of MRI voxel dimensions on carotid plaque lipid-core and fibrous cap segmentation and stress modeling. PLoS One 2015; 10:e0123031. [PMID: 25856094 PMCID: PMC4391711 DOI: 10.1371/journal.pone.0123031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 02/16/2015] [Indexed: 11/25/2022] Open
Abstract
Background The benefits of a decreased slice thickness and/or in-plane voxel size in carotid MRI for atherosclerotic plaque component quantification accuracy and biomechanical peak cap stress analysis have not yet been investigated in detail because of practical limitations. Methods In order to provide a methodology that allows such an investigation in detail, numerical simulations of a T1-weighted, contrast-enhanced, 2D MRI sequence were employed. Both the slice thickness (2 mm, 1 mm, and 0.5 mm) and the in plane acquired voxel size (0.62x0.62 mm2 and 0.31x0.31 mm2) were varied. This virtual MRI approach was applied to 8 histology-based 3D patient carotid atherosclerotic plaque models. Results A decreased slice thickness did not result in major improvements in lumen, vessel wall, and lipid-rich necrotic core size measurements. At 0.62x0.62 mm2 in-plane, only a 0.5 mm slice thickness resulted in improved minimum fibrous cap thickness measurements (a 2–3 fold reduction in measurement error) and only marginally improved peak cap stress computations. Acquiring voxels of 0.31x0.31 mm2 in-plane, however, led to either similar or significantly larger improvements in plaque component quantification and computed peak cap stress. Conclusions This study provides evidence that for currently-used 2D carotid MRI protocols, a decreased slice thickness might not be more beneficial for plaque measurement accuracy than a decreased in-plane voxel size. The MRI simulations performed indicate that not a reduced slice thickness (i.e. more isotropic imaging), but the acquisition of anisotropic voxels with a relatively smaller in-plane voxel size could improve carotid plaque quantification and computed peak cap stress accuracy.
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Affiliation(s)
- Harm A. Nieuwstadt
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, the Netherlands
| | - Zaid A. M. Kassar
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, the Netherlands
- Department of Radiology, Erasmus MC, Rotterdam, the Netherlands
| | | | - Marcel Breeuwer
- Philips Healthcare, Best, the Netherlands
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - Anton F. W. van der Steen
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, the Netherlands
- Department of Imaging Science and Technology, Delft University of Technology, Delft, the Netherlands
| | - Jolanda J. Wentzel
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, the Netherlands
| | - Frank J. H. Gijsen
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, the Netherlands
- * E-mail:
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Nieuwstadt HA, Speelman L, Breeuwer M, van der Lugt A, van der Steen AFW, Wentzel JJ, Gijsen FJH. The Influence of Inaccuracies in Carotid MRI Segmentation on Atherosclerotic Plaque Stress Computations. J Biomech Eng 2014; 136:021015. [DOI: 10.1115/1.4026178] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 12/09/2013] [Indexed: 11/08/2022]
Abstract
Biomechanical finite element analysis (FEA) based on in vivo carotid magnetic resonance imaging (MRI) can be used to assess carotid plaque vulnerability noninvasively by computing peak cap stress. However, the accuracy of MRI plaque segmentation and the influence this has on FEA has remained unreported due to the lack of a reliable submillimeter ground truth. In this study, we quantify this influence using novel numerical simulations of carotid MRI. Histological sections from carotid plaques from 12 patients were used to create 33 ground truth plaque models. These models were subjected to numerical computer simulations of a currently used clinically applied 3.0 T T1-weighted black-blood carotid MRI protocol (in-plane acquisition voxel size of 0.62 × 0.62 mm2) to generate simulated in vivo MR images from a known underlying ground truth. The simulated images were manually segmented by three MRI readers. FEA models based on the MRI segmentations were compared with the FEA models based on the ground truth. MRI-based FEA model peak cap stress was consistently underestimated, but still correlated (R) moderately with the ground truth stress: R = 0.71, R = 0.47, and R = 0.76 for the three MRI readers respectively (p < 0.01). Peak plaque stretch was underestimated as well. The peak cap stress in thick-cap, low stress plaques was substantially more accurately and precisely predicted (error of −12 ± 44 kPa) than the peak cap stress in plaques with caps thinner than the acquisition voxel size (error of −177 ± 168 kPa). For reliable MRI-based FEA to compute the peak cap stress of carotid plaques with thin caps, the current clinically used in-plane acquisition voxel size (∼0.6 mm) is inadequate. FEA plaque stress computations would be considerably more reliable if they would be used to identify thick-cap carotid plaques with low stresses instead.
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Teng Z, Sadat U, Brown AJ, Gillard JH. Plaque hemorrhage in carotid artery disease: pathogenesis, clinical and biomechanical considerations. J Biomech 2014; 47:847-58. [PMID: 24485514 PMCID: PMC3994507 DOI: 10.1016/j.jbiomech.2014.01.013] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2014] [Indexed: 12/21/2022]
Abstract
Stroke remains the most prevalent disabling illness today, with internal carotid artery luminal stenosis due to atheroma formation responsible for the majority of ischemic cerebrovascular events. Severity of luminal stenosis continues to dictate both patient risk stratification and the likelihood of surgical intervention. But there is growing evidence to suggest that plaque morphology may help improve pre-existing risk stratification criteria. Plaque components such a fibrous tissue, lipid rich necrotic core and calcium have been well investigated but plaque hemorrhage (PH) has been somewhat overlooked. In this review we discuss the pathogenesis of PH, its role in dictating plaque vulnerability, PH imaging techniques, marterial properties of atherosclerotic tissues, in particular, those obtained based on in vivo measurements and effect of PH in modulating local biomechanics.
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Affiliation(s)
- Zhongzhao Teng
- University Department of Radiology, University of Cambridge, UK; Department of Engineering, University of Cambridge, UK.
| | - Umar Sadat
- Department of Surgery, Cambridge University Hospitals NHS Foundation Trust, UK
| | - Adam J Brown
- Department of Cardiovascular Medicine, University of Cambridge, UK
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Saba L, Gao H, Raz E, Sree SV, Mannelli L, Tallapally N, Molinari F, Bassareo PP, Acharya UR, Poppert H, Suri JS. Semiautomated analysis of carotid artery wall thickness in MRI. J Magn Reson Imaging 2013; 39:1457-67. [DOI: 10.1002/jmri.24307] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 06/18/2013] [Indexed: 01/17/2023] Open
Affiliation(s)
- Luca Saba
- Department of Radiology; Azienda Ospedaliero Universitaria (A.O.U.), di Cagliari - Polo di Monserrato; Cagliari Italy
| | - Hao Gao
- Centre for Excellence in Signal and Image Processing; Department of Electronic and Electrical, University of Strathclyde; Strathclyde UK
| | - Eytan Raz
- Department of Radiology; New York University School of Medicine; New York New York USA
| | - S. Vinitha Sree
- Visiting Scientist; Global Biomedical Technologies; Roseville California USA
| | | | | | - Filippo Molinari
- Biolab, Department of Electronics; Politecnico di Torino; Torino Italy
| | - Pier Paolo Bassareo
- Department of Cardiology; Azienda Ospedaliero Universitaria (A.O.U.), di Cagliari - Polo di Monserrato; Cagliari Italy
| | | | - Holger Poppert
- Neurologische Klinik und Poliklinik Technische Universität München; München Germany
| | - Jasjit S. Suri
- Diagnostic and Monitoring Division, AtheroPoint LLC, Roseville, California, and Department of Biomedical Engineering, Idaho State University (Aff.); Pocatello Idaho USA
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Nieuwstadt HA, Geraedts TR, Truijman MTB, Kooi ME, van der Lugt A, van der Steen AFW, Wentzel JJ, Breeuwer M, Gijsen FJH. Numerical simulations of carotid MRI quantify the accuracy in measuring atherosclerotic plaque components in vivo. Magn Reson Med 2013; 72:188-201. [PMID: 23943090 DOI: 10.1002/mrm.24905] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 06/18/2013] [Accepted: 07/05/2013] [Indexed: 12/18/2022]
Abstract
PURPOSE Atherosclerotic carotid plaques can be quantified in vivo by MRI. However, the accuracy in segmentation and quantification of components such as the thin fibrous cap (FC) and lipid-rich necrotic core (LRNC) remains unknown due to the lack of a submillimeter scale ground truth. METHODS A novel approach was taken by numerically simulating in vivo carotid MRI providing a ground truth comparison. Upon evaluation of a simulated clinical protocol, MR readers segmented simulated images of cross-sectional plaque geometries derived from histological data of 12 patients. RESULTS MR readers showed high correlation (R) and intraclass correlation (ICC) in measuring the luminal area (R = 0.996, ICC = 0.99), vessel wall area (R = 0.96, ICC = 0.94) and LRNC area (R = 0.95, ICC = 0.94). LRNC area was underestimated (mean error, -24%). Minimum FC thickness showed a mediocre correlation and intraclass correlation (R = 0.71, ICC = 0.69). CONCLUSION Current clinical MRI can quantify carotid plaques but shows limitations for thin FC thickness quantification. These limitations could influence the reliability of carotid MRI for assessing plaque rupture risk associated with FC thickness. Overall, MRI simulations provide a feasible methodology for assessing segmentation and quantification accuracy, as well as for improving scan protocol design.
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Affiliation(s)
- Harm A Nieuwstadt
- Department of Biomedical Engineering, Erasmus Medical Center, Rotterdam, the Netherlands
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Huang Y, Teng Z, Sadat U, He J, Graves MJ, Gillard JH. In vivo MRI-based simulation of fatigue process: a possible trigger for human carotid atherosclerotic plaque rupture. Biomed Eng Online 2013; 12:36. [PMID: 23617791 PMCID: PMC3651387 DOI: 10.1186/1475-925x-12-36] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Accepted: 04/15/2013] [Indexed: 11/10/2022] Open
Abstract
Background Atherosclerotic plaque is subjected to a repetitive deformation due to arterial pulsatility during each cardiac cycle and damage may be accumulated over a time period causing fibrous cap (FC) fatigue, which may ultimately lead to rupture. In this study, we investigate the fatigue process in human carotid plaques using in vivo carotid magnetic resonance (MR) imaging. Method Twenty seven patients with atherosclerotic carotid artery disease were included in this study. Multi-sequence, high-resolution MR imaging was performed to depict the plaque structure. Twenty patients were found with ruptured FC or ulceration and 7 without. Modified Paris law was used to govern crack propagation and the propagation direction was perpendicular to the maximum principal stress at the element node located at the vulnerable site. Results The predicted crack initiations from 20 patients with FC defect all matched with the locations of the in vivo observed FC defect. Crack length increased rapidly with numerical steps. The natural logarithm of fatigue life decreased linearly with the local FC thickness (R2 = 0.67). Plaques (n=7) without FC defect had a longer fatigue life compared with those with FC defect (p = 0.03). Conclusion Fatigue process seems to explain the development of cracks in FC, which ultimately lead to plaque rupture.
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Affiliation(s)
- Yuan Huang
- University Department of Radiology, University of Cambridge, Level 5, Box 218, Hills Road, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
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Teng Z, Sadat U, Wang W, Bahaei NS, Chen S, Young VE, Graves MJ, Gillard JH. Intraplaque stretch in carotid atherosclerotic plaque--an effective biomechanical predictor for subsequent cerebrovascular ischemic events. PLoS One 2013; 8:e61522. [PMID: 23626694 PMCID: PMC3634006 DOI: 10.1371/journal.pone.0061522] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 03/11/2013] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Stretch is a mechanical parameter, which has been proposed previously to affect the biological activities in different tissues. This study explored its utility in determining plaque vulnerability. METHODS One hundred and six patients with mild to moderate carotid stenosis were recruited in this study (53 symptomatic and 53 asymptomatic). High resolution, multi-sequence magnetic resonance (MR) imaging was performed to delineate various plaque components. Finite element method was used to predict high stretch concentration within the plaque. RESULTS During a two-year follow-up, 11 patients in symptomatic group and 3 in asymptomatic group experienced recurrent cerebrovascular events. Plaque stretch at systole and stretch variation during one cardiac cycle was greater in symptomatic group than those in the asymptomatic. Within the symptomatic group, a similar trend was observed in patients with recurrent events compared to those without. CONCLUSION Plaques with high stretch concentration and large stretch variation are associated with increased risk of future cerebrovascular events.
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Affiliation(s)
- Zhongzhao Teng
- University Department of Radiology, University of Cambridge, Cambridge, United Kingdom.
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Computer Simulations in Stroke Prevention: Design Tools and Virtual Strategies Towards Procedure Planning. Cardiovasc Eng Technol 2013. [DOI: 10.1007/s13239-013-0134-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Exarchos TP, Sakellarios A, Siogkas PK, Fotiadis DI, Milosevic Z, Nikolic D, Filipovic N, Marraccini P, Vozzi F, Parodi O. Patient specific multiscale modelling for plaque formation and progression. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2012:2893-6. [PMID: 23366529 DOI: 10.1109/embc.2012.6346568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We present a three-dimensional model of plaque formation and progression that was tested in a set of patients who underwent coronary Computed Tomography angiography (CTA) for anginal symptoms. The 3D blood flow is described by the Navier-Stokes equations, together with the continuity equation. Mass transfer within the blood lumen and through the arterial wall is coupled with the blood flow and is modeled by a convection-diffusion equation. The Low Density Lipoprotein (LDL) transports in lumen of the vessel and through the vessel tissue (which has a mass consumption term) are coupled by Kedem-Katchalsky equations. The inflammatory process is modeled using three additional reaction-diffusion partial differential equations. A full three-dimensional model was created. Furthermore, features potentially affecting plaque growth, such as patient risk score, circulating biomarkers, localization and composition of the initial plaque, and coronary vasodilating capability were also investigated. The proof of concept of the model effectiveness was assessed 6 months after the baseline evaluation.
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Affiliation(s)
- T P Exarchos
- Foundation for Research and Technology Hellas, Institute of Molecular Biology and Biotechnology, University of Ioannina, Ioannina, GR 45110, Greece.
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Nieuwstadt H, Akyildiz A, Speelman L, Virmani R, van der Lugt A, van der Steen A, Wentzel J, Gijsen F. The influence of axial image resolution on atherosclerotic plaque stress computations. J Biomech 2013; 46:689-95. [DOI: 10.1016/j.jbiomech.2012.11.042] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Revised: 11/02/2012] [Accepted: 11/21/2012] [Indexed: 11/28/2022]
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Parodi O, Exarchos TP, Marraccini P, Vozzi F, Milosevic Z, Nikolic D, Sakellarios A, Siogkas PK, Fotiadis DI, Filipovic N. Patient-Specific Prediction of Coronary Plaque Growth From CTA Angiography: A Multiscale Model for Plaque Formation and Progression. ACTA ACUST UNITED AC 2012; 16:952-65. [DOI: 10.1109/titb.2012.2201732] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Gao H, Long Q, Kumar Das S, Halls J, Graves M, Gillard JH, Li ZY. Study of carotid arterial plaque stress for symptomatic and asymptomatic patients. J Biomech 2011; 44:2551-7. [PMID: 21824619 DOI: 10.1016/j.jbiomech.2011.07.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 07/06/2011] [Accepted: 07/08/2011] [Indexed: 11/16/2022]
Abstract
Stroke is one of the leading causes of death in the world, resulting mostly from the sudden ruptures of atherosclerosis carotid plaques. Until now, the exact plaque rupture mechanism has not been fully understood, and also the plaque rupture risk stratification. The advanced multi-spectral magnetic resonance imaging (MRI) has allowed the plaque components to be visualized in-vivo and reconstructed by computational modeling. In the study, plaque stress analysis using fully coupled fluid structure interaction was applied to 20 patients (12 symptomatic and 8 asymptomatic) reconstructed from in-vivo MRI, followed by a detailed biomechanics analysis, and morphological feature study. The locally extreme stress conditions can be found in the fibrous cap region, 85% at the plaque shoulder based on the present study cases. Local maximum stress values predicted in the plaque region were found to be significantly higher in symptomatic patients than that in asymptomatic patients (200 ± 43 kPa vs. 127 ± 37 kPa, p=0.001). Plaque stress level, defined by excluding 5% highest stress nodes in the fibrous cap region based on the accumulative histogram of stress experienced on the computational nodes in the fibrous cap, was also significantly higher in symptomatic patients than that in asymptomatic patients (154 ± 32 kPa vs. 111 ± 23 kPa, p<0.05). Although there was no significant difference in lipid core size between the two patient groups, symptomatic group normally had a larger lipid core and a significantly thinner fibrous cap based on the reconstructed plaques using 3D interpolation from stacks of 2D contours. Plaques with a higher stenosis were more likely to have extreme stress conditions upstream of plaque throat. The combined analyses of plaque MR image and plaque stress will advance our understanding of plaque rupture, and provide a useful tool on assessing plaque rupture risk.
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Affiliation(s)
- Hao Gao
- Centre for excellence in Signal and Image Processing, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow G11XW, UK
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Bijari PB, Antiga L, Wasserman BA, Steinman DA. Scan-Rescan reproducibility of carotid bifurcation geometry from routine contrast-enhanced MR angiography. J Magn Reson Imaging 2011; 33:482-9. [PMID: 21274992 DOI: 10.1002/jmri.22440] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
PURPOSE To demonstrate the feasibility of rapid and reliable geometric characterization of normal carotid bifurcation geometry from routine 3D contrast-enhanced magnetic resonance (MR) angiograms. MATERIALS AND METHODS Repeat scans of 61 participants, acquired as part of the Atherosclerosis Risk in Communities (ARIC) Carotid MRI substudy, were digitally segmented using automated 3D level set methods, relying on an operator only to select the branch endpoints and thresholds for the 3D lumen surface initialization. Geometric factors characterizing the 3D lumen geometry were then extracted automatically. RESULTS Of 122 scans, 117 could be segmented within 5 minutes each, with 40% being of sufficiently high quality to require less than 2 minutes each. Irrespective of scan quality, geometric factors were found to be highly reproducible, with intraclass correlation coefficients (ICCs) typically above 0.9. The reconstructed lumen surfaces were reproducible to <0.3 mm on average, comparable to previous MRI-based reproducibility studies. Owing to the automated nature of the analysis, operator reliability was near-perfect (ICC >0.99), with lumen surface differences <0.1 mm. CONCLUSION The 3D geometry of the carotid bifurcation can be characterized rapidly and with a high degree of consistency, even for suboptimal image qualities. This bodes well for large-scale retrospective or prospective studies aimed at teasing out the influence of local vs. systemic risk factors for early atherosclerosis.
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Affiliation(s)
- Payam B Bijari
- Biomedical Simulation Laboratory and Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
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Sadat U, Teng Z, Young VE, Li ZY, Gillard JH. Utility of Magnetic Resonance Imaging-Based Finite Element Analysis for the Biomechanical Stress Analysis of Hemorrhagic and Non-Hemorrhagic Carotid Plaques. Circ J 2011; 75:884-9. [DOI: 10.1253/circj.cj-10-0719] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Umar Sadat
- University Department of Radiology, University of Cambridge
- Cambridge Vascular Unit, Cambridge University Hospitals NHS Foundation Trust
| | - Zhongzhao Teng
- University Department of Radiology, University of Cambridge
| | | | - Zhi Yong Li
- University Department of Radiology, University of Cambridge
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Sadat U, Teng Z, Young VE, Walsh SR, Li ZY, Graves MJ, Varty K, Gillard JH. Association between biomechanical structural stresses of atherosclerotic carotid plaques and subsequent ischaemic cerebrovascular events--a longitudinal in vivo magnetic resonance imaging-based finite element study. Eur J Vasc Endovasc Surg 2010; 40:485-91. [PMID: 20724181 DOI: 10.1016/j.ejvs.2010.07.015] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Accepted: 07/19/2010] [Indexed: 11/16/2022]
Abstract
BACKGROUND High-resolution magnetic resonance (MR) imaging has been used for MR imaging-based structural stress analysis of atherosclerotic plaques. The biomechanical stress profile of stable plaques has been observed to differ from that of unstable plaques; however, the role that structural stresses play in determining plaque vulnerability remains speculative. METHODS A total of 61 patients with previous history of symptomatic carotid artery disease underwent carotid plaque MR imaging. Plaque components of the index artery such as fibrous tissue, lipid content and plaque haemorrhage (PH) were delineated and used for finite element analysis-based maximum structural stress (M-C Stress) quantification. These patients were followed up for 2 years. The clinical end point was occurrence of an ischaemic cerebrovascular event. The association of the time to the clinical end point with plaque morphology and M-C Stress was analysed. RESULTS During a median follow-up duration of 514 days, 20% of patients (n = 12) experienced an ischaemic event in the territory of the index carotid artery. Cox regression analysis indicated that M-C Stress (hazard ratio (HR): 12.98 (95% confidence interval (CI): 1.32-26.67, p = 0.02), fibrous cap (FC) disruption (HR: 7.39 (95% CI: 1.61-33.82), p = 0.009) and PH (HR: 5.85 (95% CI: 1.27-26.77), p = 0.02) are associated with the development of subsequent cerebrovascular events. Plaques associated with future events had higher M-C Stress than those which had remained asymptomatic (median (interquartile range, IQR): 330 kPa (229-494) vs. 254 kPa (166-290), p = 0.04). CONCLUSIONS High biomechanical structural stresses, in addition to FC rupture and PH, are associated with subsequent cerebrovascular events.
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Affiliation(s)
- U Sadat
- University Department of Radiology, University of Cambridge, Cambridge, UK.
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Creane A, Maher E, Sultan S, Hynes N, Kelly DJ, Lally C. Finite element modelling of diseased carotid bifurcations generated from in vivo computerised tomographic angiography. Comput Biol Med 2010; 40:419-29. [DOI: 10.1016/j.compbiomed.2010.02.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 01/15/2010] [Accepted: 02/10/2010] [Indexed: 11/29/2022]
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Abstract
This review examines the state of the art in vessel wall imaging by magnetic resonance imaging (MRI) with an emphasis on the biomechanical assessment of atherosclerotic plaque. Three areas of advanced techniques are discussed. First, alternative contrast mechanisms, including susceptibility, magnetization transfer, diffusion, and perfusion, are presented as to how they facilitate accurate determination of plaque constituents underlying biomechanics. Second, imaging technologies including hardware and sequences, are reviewed as to how they provide the resolution and signal-to-noise ratio necessary for determining plaque structure. Finally, techniques for combining MRI data into an overall assessment of plaque biomechanical properties, including wall shear stress and internal plaque strain, are presented. The paper closes with a discussion of the extent to which these techniques have been applied to different arteries commonly targeted by vessel wall MRI.
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Affiliation(s)
- William S Kerwin
- Department of Radiology, University of Washington, Seattle, WA 98109, USA.
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