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Ntaios G, Baumgartner H, Doehner W, Donal E, Edvardsen T, Healey JS, Iung B, Kamel H, Kasner SE, Korompoki E, Navi BB, Pristipino C, Saba L, Schnabel RB, Svennberg E, Lip GYH. Embolic strokes of undetermined source: a clinical consensus statement of the ESC Council on Stroke, the European Association of Cardiovascular Imaging and the European Heart Rhythm Association of the ESC. Eur Heart J 2024; 45:1701-1715. [PMID: 38685132 PMCID: PMC11107123 DOI: 10.1093/eurheartj/ehae150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/02/2024] Open
Abstract
One in six ischaemic stroke patients has an embolic stroke of undetermined source (ESUS), defined as a stroke with unclear aetiology despite recommended diagnostic evaluation. The overall cardiovascular risk of ESUS is high and it is important to optimize strategies to prevent recurrent stroke and other cardiovascular events. The aim of clinicians when confronted with a patient not only with ESUS but also with any other medical condition of unclear aetiology is to identify the actual cause amongst a list of potential differential diagnoses, in order to optimize secondary prevention. However, specifically in ESUS, this may be challenging as multiple potential thromboembolic sources frequently coexist. Also, it can be delusively reassuring because despite the implementation of specific treatments for the individual pathology presumed to be the actual thromboembolic source, patients can still be vulnerable to stroke and other cardiovascular events caused by other pathologies already identified during the index diagnostic evaluation but whose thromboembolic potential was underestimated. Therefore, rather than trying to presume which particular mechanism is the actual embolic source in an ESUS patient, it is important to assess the overall thromboembolic risk of the patient through synthesis of the individual risks linked to all pathologies present, regardless if presumed causally associated or not. In this paper, a multi-disciplinary panel of clinicians/researchers from various backgrounds of expertise and specialties (cardiology, internal medicine, neurology, radiology and vascular surgery) proposes a comprehensive multi-dimensional assessment of the overall thromboembolic risk in ESUS patients through the composition of individual risks associated with all prevalent pathologies.
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Affiliation(s)
- George Ntaios
- Department of Internal Medicine, School of Health Sciences, University of Thessaly, Larissa University Hospital, Larissa 41132, Greece
| | - Helmut Baumgartner
- Department of Cardiology III: Adult Congenital and Valvular Heart Disease, University Hospital Muenster, Muenster, Germany
| | - Wolfram Doehner
- Department of Cardiology (Campus Virchow), Center of Stroke Research Berlin, German Centre for Cardiovascular Research (DZHK) partner site Berlin, Berlin Institute of Health-Center for Regenerative Therapies, Deutsches Herzzentrum der Charité, Charité, Berlin, Germany
| | - Erwan Donal
- Service de Cardiologie et CIC-IT 1414, CHU Rennes, Rennes, France
| | - Thor Edvardsen
- Department of Cardiology, Faculty of Medicine, Oslo University Hospital, Rikshospitalet, University of Oslo, Oslo, Norway
| | - Jeff S Healey
- Cardiology Division, McMaster University, Hamilton, Canada
| | - Bernard Iung
- Bichat Hospital, APHP and Université Paris-Cité, INSERM LVTS U1148, Paris, France
| | - Hooman Kamel
- Clinical and Translational Neuroscience Unit, Feil Family Brain and Mind Research Institute, Department of Neurology, Weill Cornell Medicine, New York, NY, USA
| | - Scott E Kasner
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Eleni Korompoki
- Department of Clinical Therapeutics, Alexandra Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Babak B Navi
- Clinical and Translational Neuroscience Unit, Feil Family Brain and Mind Research Institute, Department of Neurology, Weill Cornell Medicine, New York, NY, USA
- Department of Neurology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Christian Pristipino
- Interventional and Intensive Cardiology Unit, San Filippo Neri Hospital, ASL Roma 1, Rome, Italy
| | - Luca Saba
- Department of Radiology, Azienda Ospedaliero Universitaria (A.O.U.), di Cagliari—Polo di Monserrato, Cagliari, Italy
| | - Renate B Schnabel
- Department of Cardiology, University Heart & Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Luebeck, Germany
| | - Emma Svennberg
- Department of Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Gregory Y H Lip
- Liverpool Centre for Cardiovascular Science at University of Liverpool, Liverpool John Moores University, Liverpool Heart & Chest Hospital, Liverpool, UK
- Danish Center for Health Services Research, Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
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Saba L, Cau R, Spinato G, Suri JS, Melis M, De Rubeis G, Antignani P, Gupta A. Carotid stenosis and cryptogenic stroke. J Vasc Surg 2024; 79:1119-1131. [PMID: 38190926 DOI: 10.1016/j.jvs.2024.01.004] [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: 12/13/2023] [Revised: 12/30/2023] [Accepted: 01/04/2024] [Indexed: 01/10/2024]
Abstract
OBJECTIVES Cryptogenic stroke represents a type of ischemic stroke with an unknown origin, presenting a significant challenge in both stroke management and prevention. According to the Trial of Org 10,172 in Acute Stroke Treatment criteria, a stroke is categorized as being caused by large artery atherosclerosis only when there is >50% luminal narrowing of the ipsilateral internal carotid artery. However, nonstenosing carotid artery plaques can be an underlying cause of ischemic stroke. Indeed, emerging evidence documents that some features of plaque vulnerability may act as an independent risk factor, regardless of the degree of stenosis, in precipitating cerebrovascular events. This review, drawing from an array of imaging-based studies, explores the predictive values of carotid imaging modalities in the detection of nonstenosing carotid plaque (<50%), that could be the cause of a cerebrovascular event when some features of vulnerability are present. METHODS Google Scholar, Scopus, and PubMed were searched for articles on cryptogenic stroke and those reporting the association between cryptogenic stroke and imaging features of carotid plaque vulnerability. RESULTS Despite extensive diagnostic evaluations, the etiology of a considerable proportion of strokes remains undetermined, contributing to the recurrence rate and persistent morbidity in affected individuals. Advances in imaging modalities, such as magnetic resonance imaging, computed tomography scans, and ultrasound examination, facilitate more accurate detection of nonstenosing carotid artery plaque and allow better stratification of stroke risk, leading to a more tailored treatment strategy. CONCLUSIONS Early detection of nonstenosing carotid plaque with features of vulnerability through carotid imaging techniques impacts the clinical management of cryptogenic stroke, resulting in refined stroke subtype classification and improved patient management. Additional research is required to validate these findings and recommend the integration of these state-of-the-art imaging methodologies into standard diagnostic protocols to improve stroke management and prevention.
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Affiliation(s)
- Luca Saba
- Department of Radiology, Azienda Ospedaliero Universitaria (A.O.U.), Cagliari, Italy.
| | - Riccardo Cau
- Department of Radiology, Azienda Ospedaliero Universitaria (A.O.U.), Cagliari, Italy
| | - Giacomo Spinato
- Department of Neurosciences, Section of Otolaryngology and Regional Centre for Head and Neck Cancer, University of Padova, Treviso, Italy
| | - Jasjit S Suri
- Stroke Monitoring and Diagnostic Division, AtheroPoint™, Roseville, CA
| | - Marta Melis
- Department of Neurology, Azienda Ospedaliero Universitaria (A.O.U.), Cagliari, Italy
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Curcio N, Rosato A, Mazzaccaro D, Nano G, Conti M, Matrone G. 3D patient-specific modeling and structural finite element analysis of atherosclerotic carotid artery based on computed tomography angiography. Sci Rep 2023; 13:19911. [PMID: 37964071 PMCID: PMC10645924 DOI: 10.1038/s41598-023-46949-5] [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: 05/10/2023] [Accepted: 11/07/2023] [Indexed: 11/16/2023] Open
Abstract
The assessment of carotid plaque vulnerability is a relevant clinical information that can help prevent adverse cerebrovascular events. To this aim, in this study, we propose a patient-specific computational workflow to quantify the stress distribution in an atherosclerotic carotid artery, by means of geometric modeling and structural simulation of the plaque and vessel wall. Ten patients were involved in our study. Starting with segmentation of the lumen, calcific and lipid plaque components from computed tomography angiography images, the fibrous component and the vessel wall were semi-automatically reconstructed with an ad-hoc procedure. Finite element analyses were performed using local pressure values derived from ultrasound imaging. Simulation outputs were analyzed to assess how mechanical factors influence the stresses within the atherosclerotic wall. The developed reconstruction method was first evaluated by comparing the results obtained using the automatically generated fibrous component model and the one derived from image segmentation. The high-stress regions in the carotid artery wall around plaques suggest areas of possible rupture. In mostly lipidic and heterogeneous plaques, the highest stresses are localized at the interface between the lipidic components and the lumen, in the fibrous cap.
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Affiliation(s)
- Nicoletta Curcio
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy
| | - Antonio Rosato
- 3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Daniela Mazzaccaro
- Operative Unit of Vascular Surgery, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Giovanni Nano
- Operative Unit of Vascular Surgery, IRCCS Policlinico San Donato, San Donato Milanese, Italy
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Michele Conti
- Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy
| | - Giulia Matrone
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy.
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The MRI enhancement ratio and plaque steepness may be more accurate for predicting recurrent ischemic cerebrovascular events in patients with intracranial atherosclerosis. Eur Radiol 2022; 32:7004-7013. [PMID: 35771249 DOI: 10.1007/s00330-022-08893-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/22/2022] [Accepted: 04/18/2022] [Indexed: 12/28/2022]
Abstract
OBJECTIVES To assess the complementary value of high-resolution multi-contrast MRI (hrMRI) in identifying symptomatic patients with intracranial atherosclerosis (ICAS) who are likely to experience recurrent ischemic cerebrovascular events. METHODS In this retrospective cohort study, eighty patients with acute ischemic events attributed to ICAS who underwent hrMRI examination between January 2015 and January 2019 were included. Median follow-up for all patients was 30 months (range: 1 to 52 months) and recurrent ischemic cerebrovascular events were recorded. Cox regression analysis and time-dependent ROC were performed to quantify the association between the plaque characteristics and recurrent events. RESULTS During the follow-up, 14 patients experienced recurrent ischemic cerebrovascular events. Young males and those with diabetes and poor medication persistence were more likely to experience recurrent events. ICAS in patients with recurrence had significantly higher enhancement ratio and steepness which is defined as the ratio between the plaque height and length than those without (p < 0.001 and p = 0.015, respectively). After adjustment of clinical factors, enhancement ratio (HR, 13.13 [95% CI, 3.58-48.20], p < 0.001) and plaque steepness (HR, 110.27 [95% CI, 4.75-2560.91], p = 0.003) were independent imaging biomarkers associated with recurrent events. Time-dependent ROC indicated that integrated high enhancement ratio and steepness into clinical risk factors improved discrimination power with the ROC increased from 0.79 to 0.94 (p = 0.008). CONCLUSIONS The enhancement ratio and plaque steepness improved the accuracy over traditional clinical risk factors in predicting recurrent ischemic cerebrovascular events for patients with ICAS. KEY POINTS • High-resolution magnetic resonance imaging helps clinicians to evaluate high-risk Intracranial plaque. • The higher enhancement ratio and plaque steepness (= height/length) were the primary biomarkers associated with future ischemic cerebrovascular events. • High-resolution magnetic resonance imaging combined with clinical characteristics showed a higher accuracy for the prediction of recurrent events in patients with intracranial atherosclerosis.
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Helou B, Bel-Brunon A, Dupont C, Ye W, Silvestro C, Rochette M, Lucas A, Kaladji A, Haigron P. Influence of balloon design, plaque material composition, and balloon sizing on acute post angioplasty outcomes: An implicit finite element analysis. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3499. [PMID: 33998779 DOI: 10.1002/cnm.3499] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 05/08/2021] [Indexed: 06/12/2023]
Abstract
In this work we propose a generic modeling approach for simulating percutaneous transluminal angioplasty (PTA) endovascular treatment, and evaluating the influence of balloon design, plaque composition, and balloon sizing on acute post-procedural outcomes right after PTA, without stent implantation. Clinically-used PTA balloons were classified into two categories according to their compliance characteristics, and were modeled correspondingly. Self-defined elastoplastic constitutive laws were implemented within the plaque and artery models, after calibration based on experimental and clinical data. Finite element method (FEM) implicit solver was used to simulate balloon inflation and deflation. Besides balloon profile at max inflation, results are mainly assessed in terms of the elastic recoil ratio (ERR) and lumen gain ratio (LGR) obtained immediately after PTA. No variations in ERR nor LGR values were detected when the balloon design changed, despite the differences observed in their profile at max inflation. Moreover, LGR and ERR inversely varied with the augmentation of calcification level within the plaque (-11% vs. +4% respectively, from fully lipidic to fully calcified plaque). Furthermore, results showed a direct correlation between balloon sizing and LGR and ERR, with noticeably higher rates of change for LGR (+18% and +2% for LGR and ERR respectively for a calcified plaque and a balloon pressure increasing from 10 to 14 atm). However a larger LGR comes with a higher risk of arterial rupture. This proposed methodology opens the way for evaluation of angioplasty balloon selections towards clinical procedure optimization.
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Affiliation(s)
- Bernard Helou
- Univ Rennes, CHU Rennes, Inserm, LTSI - UMR 1099, Rennes, France
| | - Aline Bel-Brunon
- Univ Lyon, INSA-Lyon, CNRS UMR5259, LaMCoS, Villeurbanne, France
| | - Claire Dupont
- Univ Rennes, CHU Rennes, Inserm, LTSI - UMR 1099, Rennes, France
| | | | - Claudio Silvestro
- Medtronic, Aortic Peripheral & Venous (APV) Group, Santa Rosa, California, USA
| | | | - Antoine Lucas
- Univ Rennes, CHU Rennes, Inserm, LTSI - UMR 1099, Rennes, France
| | - Adrien Kaladji
- Univ Rennes, CHU Rennes, Inserm, LTSI - UMR 1099, Rennes, France
| | - Pascal Haigron
- Univ Rennes, CHU Rennes, Inserm, LTSI - UMR 1099, Rennes, France
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Evans NR, Tarkin JM, Le EP, Sriranjan RS, Corovic A, Warburton EA, Rudd JH. Integrated cardiovascular assessment of atherosclerosis using PET/MRI. Br J Radiol 2020; 93:20190921. [PMID: 32238077 DOI: 10.1259/bjr.20190921] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Atherosclerosis is a systemic inflammatory disease typified by the development of lipid-rich atheroma (plaques), the rupture of which are a major cause of myocardial infarction and stroke. Anatomical evaluation of the plaque considering only the degree of luminal stenosis overlooks features associated with vulnerable plaques, such as high-risk morphological features or pathophysiology, and hence risks missing vulnerable or ruptured non-stenotic plaques. Consequently, there has been interest in identifying these markers of vulnerability using either MRI for morphology, or positron emission tomography (PET) for physiological processes involved in atherogenesis. The advent of hybrid PET/MRI scanners offers the potential to combine the strengths of PET and MRI to allow comprehensive assessment of the atherosclerotic plaque. This review will discuss the principles and technical aspects of hybrid PET/MRI assessment of atherosclerosis, and consider how combining the complementary modalities of PET and MRI has already furthered our understanding of atherogenesis, advanced drug development, and how it may hold potential for clinical application.
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Affiliation(s)
- Nicholas R Evans
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Jason M Tarkin
- Division of Cardiovascular Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Elizabeth Pv Le
- Division of Cardiovascular Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Rouchelle S Sriranjan
- Division of Cardiovascular Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Andrej Corovic
- Division of Cardiovascular Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Elizabeth A Warburton
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - James Hf Rudd
- Division of Cardiovascular Medicine, University of Cambridge, Cambridge, United Kingdom
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Seyedsaadat SM, Rizvi A, Alzuabi M, Dugani SB, Murad MH, Huston J, Saba L, Brinjikji W. Correlation of MRI-detected vulnerable carotid plaques with clinical presentation: a systematic review and meta-analysis. J Neurosurg Sci 2019; 64:263-271. [PMID: 31738030 DOI: 10.23736/s0390-5616.19.04820-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
INTRODUCTION To determine the association between magnetic resonance imaging (MRI)-detected vulnerable Carotid Plaques and clinical presentation related to ipsilateral carotid artery territory. EVIDENCE ACQUISITION We searched three databases including Ovid MEDLINE, Ovid EMBASE, and Scopus from 2000 to 2018 for studies that evaluated vulnerable carotid plaques by MRI defined as intraplaque hemorrhage (IPH), lipid-rich necrotic core (LRNC), or thinning/rupture of the fibrous cap (TRFC). Data on study characteristics, clinical presentation, and MRI findings were extracted. Publication bias, methodologic quality, and study heterogeneity were assessed. Random-effects meta-analysis model was used to estimate incidence rate ratio (IRR) and 95% confidence intervals (CI) of MRI-detected vulnerable carotid plaque between symptomatic and asymptomatic arteries. EVIDENCE SYNTHESIS Of 2855 studies, 33 studies containing 6210 participants with 8401 assessed arteries were included. Overall, the risk of bias was moderate in 13, and low in 20 studies. The prevalence of MRI-positive IPH, TRFC, and LRNC were higher in symptomatic groups compared with the asymptomatic groups. In 11 studies that compared vulnerable carotid plaques between symptomatic and asymptomatic groups, symptomatic presentation was correlated with increased risk of IPH (IRR=1.57; 95% CI: 1.24-1.99), TRFC (IRR=2.26; 95% CI: 1.83 to 3.76), and LRNC (IRR=1.95; 95% CI: 1.28 to 2.97), respectively. CONCLUSIONS The presence of MRI-positive vulnerable carotid plaques including IPH, LRNC, and TRFC is positively associated with symptomatic clinical presentation. Therefore, carotid plaque MRI might be a useful risk stratification tool in determining the risk of ischemic stroke.
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Affiliation(s)
| | - Asim Rizvi
- Department of Radiology, Mayo Clinic, Rochester, MN, USA.,University of Texas Medical Branch, Galveston, TX, USA
| | - Muayad Alzuabi
- Evidence-based Practice Center, Mayo Clinic, Rochester, MN, USA
| | - Sagar B Dugani
- Division of Hospital Internal Medicine, Mayo Clinic, Rochester, MN, USA
| | - M Hassan Murad
- Evidence-based Practice Center, Mayo Clinic, Rochester, MN, USA
| | - John Huston
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Luca Saba
- Department of Radiology, University of Cagliari, Cagliari, Italy
| | - Waleed Brinjikji
- Department of Radiology, Mayo Clinic, Rochester, MN, USA - .,Joint Department of Medical Imaging, Toronto Western Hospital, Toronto, ON, Canada
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Teng Z, Brown AJ, Gillard JH. Carotid Intraplaque Hemorrhage: A Biomarker for Subsequent Ischemic Cerebrovascular Event? Cerebrovasc Dis 2018; 43:257-258. [PMID: 28259890 DOI: 10.1159/000462994] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Zhongzhao Teng
- Department of Radiology, University of Cambridge, Cambridge, UK
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Jiang B, He D, Zhang L, Ye M. Risk prediction of cerebrovascular events with carotid plaque magneitc resonance analysis: A meta-analysis. J Neuroradiol 2018; 46:117-123. [PMID: 29920350 DOI: 10.1016/j.neurad.2018.05.003] [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] [Received: 10/02/2017] [Revised: 01/04/2018] [Accepted: 05/25/2018] [Indexed: 10/14/2022]
Abstract
BACKGROUND AND PURPOSE It is not conclusive that magnetic resonance (MR)-based carotid atherosclerotic plaque assessment identifies high-risk features associated with cerebrovascular events. We aimed to systematically summarize the association of MR imaging (MRI)-determined intraplaque hemorrhage (IPH), lipid-rich necrotic core (LRNC), and thinning/rupture of the fibrous cap (TRFC) with subsequent ischemic events. MATERIALS AND METHODS We performed a comprehensive literature search evaluating the association of MRI-based carotid plaque composition with ischemic outcomes. We included cohort studies examining IPH, LRNC, or TRFC with mean follow-up of≥6 months and an outcome measure of ipsilateral ischemic events. A meta-analysis was done according to the Cochrane guideline. RESULTS We identified 13 studies including 1.150 patients and 1.208 analyzed carotid arteries, with mean follow-up of 21.1 months. The hazard ratios (HR) for IPH, LRNC, and TRFC as predictors of subsequent ischemic events were 4.41 (95% CI: 2.87, 6.79), 3.00 (95% CI: 1.51, 5.95), and 5.94 (95% CI: 2.66, 13.28), respectively. The predictive value of carotid plaque MRI for ischemic events was acceptable, with sensitivity of 0.80 (95% CI: 0.66, 0.90) and specificity of 0.63 (95% CI: 0.57, 0.68). However, it was limited to confirm or exclude future ischemic events in clinical context, with positive likelihood ratio (LR) of 2.2 (95% CI: 1.9, 2.5) and negative LR of 0.31 (95% CI: 0.18, 0.55). No statistically significant heterogeneity or publication bias was observed. CONCLUSION The presence of IPH, LRNC, and TRFC determined by MRI is associated with increased risk of future ischemic events, but its predictive value is moderate and should not be used for confirmation or exclusion of future ischemic events in clinical context.
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Affiliation(s)
- Binghu Jiang
- Department of radiology and Imaging Institute of Rehabilitation and Development of Brain Function, The Second Clinical Medical College of North Sichuan Medical College, Nanchong Central Hospital, 637000 Nanchong, China
| | - Dongmei He
- Department of neurology, BenQ Medical Center, Nanjing Medical University, N(o) 71, Hexi avenue, Jianye District, Nanjing 210019, China
| | - Liwen Zhang
- Department of neurology, BenQ Medical Center, Nanjing Medical University, N(o) 71, Hexi avenue, Jianye District, Nanjing 210019, China
| | - Min Ye
- Department of neurology, BenQ Medical Center, Nanjing Medical University, N(o) 71, Hexi avenue, Jianye District, Nanjing 210019, China.
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Paraskevas KI, Veith FJ, Spence JD. How to identify which patients with asymptomatic carotid stenosis could benefit from endarterectomy or stenting. Stroke Vasc Neurol 2018; 3:92-100. [PMID: 30022795 PMCID: PMC6047337 DOI: 10.1136/svn-2017-000129] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 02/06/2018] [Accepted: 02/07/2018] [Indexed: 11/23/2022] Open
Abstract
Offering routine carotid endarterectomy (CEA) or carotid artery stenting (CAS) to patients with asymptomatic carotid artery stenosis (ACS) is no longer considered as the optimal management of these patients. Equally suboptimal, however, is the policy of offering only best medical treatment (BMT) to all patients with ACS and not considering any of them for prophylactic CEA. In the last few years, there have been many studies aiming to identify reliable predictors of future cerebrovascular events that would allow the identification of patients with high-risk ACS and offer a prophylactic carotid intervention only to these patients to prevent them from becoming symptomatic. All patients with ACS should receive BMT. The present article will summarise the evidence suggesting ways to identify these high-risk asymptomatic individuals, namely: (1) microemboli detection on transcranial Doppler, (2) plaque echolucency on Duplex ultrasound, (3) progression in the severity of ACS, (4) silent embolic infarcts on brain CT/MRI, (5) reduced cerebrovascular reserve, (6) increased size of juxtaluminal hypoechoic area, (7) identification of intraplaque haemorrhage using MRI and (8) carotid ulceration. The evidence suggests that approximately 10%-15% of patents with asymptomatic stenosis might benefit from intervention; this will become more clear after publication of ongoing studies comparing stenting or endarterectomy with best medical therapy. In the meantime, no patient should be offered intervention unless there is evidence of high risk of ipsilateral stroke, from modalities such as those discussed here.
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Affiliation(s)
- Kosmas I Paraskevas
- Department of Vascular and Endovascular Surgery, Royal Free Hospital, London, UK
| | - Frank J Veith
- Department of Vascular Surgery, New York University Langone Medical Center, New York, USA
- Department of Vascular Surgery, Cleveland Clinic, Cleveland, Ohio, USA
| | - J David Spence
- Stroke Prevention & Atherosclerosis Research Centre, Robarts Research Institute, Western University, London, Canada
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11
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Cattaneo M, Wyttenbach R, Corti R, Staub D, Gallino A. The Growing Field of Imaging of Atherosclerosis in Peripheral Arteries. Angiology 2018; 70:20-34. [PMID: 29783854 DOI: 10.1177/0003319718776122] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In the past decades, peripheral arteries have represented a model for the comprehension of atherosclerosis as well as for the development of new diagnostic imaging modalities and therapeutic strategies. Peripheral arteries may represent a window to study atherosclerosis. Pathology has prominently contributed to move the clinical and research attention from the arterial lumen stenosis and angiography to morphological and functional imaging techniques. Evidence from large and prospective cohort or randomized controlled studies is still modest. Nevertheless, several emerging imaging investigations represent a potential tool for a comprehensive "in vivo" evaluation of the entire natural history of peripheral atherosclerosis. This constitutes a demanding assignment, as it would be desirable to obtain both single-lesion focused and extensive arterial system views to achieve the most accurate prognostic information. Our narrative review rests upon the fundamental pathological evidence, summarizing the rapidly growing field of imaging of atherosclerosis in peripheral arteries and presenting a selection of both currently available and emerging imaging techniques.
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Affiliation(s)
- Mattia Cattaneo
- 1 Cardiovascular Medicine Department, Ospedale Regionale di Bellinzona e Valli, San Giovanni, Bellinzona, Switzerland
| | - Rolf Wyttenbach
- 2 Radiology Department, Ospedale Regionale di Bellinzona e Valli, San Giovanni, Bellinzona, Switzerland.,3 University of Bern, Bern, Switzerland
| | - Roberto Corti
- 4 Cardiology Department, HerzKlinik Hirslanden, Zurich, Switzerland
| | - Daniel Staub
- 5 Angiology Department, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Augusto Gallino
- 1 Cardiovascular Medicine Department, Ospedale Regionale di Bellinzona e Valli, San Giovanni, Bellinzona, Switzerland.,6 University of Zurich, Zurich, Switzerland
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Hoffman AH, Teng Z, Zheng J, Wu Z, Woodard PK, Billiar KL, Wang L, Tang D. Stiffness Properties of Adventitia, Media, and Full Thickness Human Atherosclerotic Carotid Arteries in the Axial and Circumferential Directions. J Biomech Eng 2018; 139:2653366. [PMID: 28857112 DOI: 10.1115/1.4037794] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Indexed: 11/08/2022]
Abstract
Arteries can be considered as layered composite material. Experimental data on the stiffness of human atherosclerotic carotid arteries and their media and adventitia layers are very limited. This study used uniaxial tests to determine the stiffness (tangent modulus) of human carotid artery sections containing American Heart Association type II and III lesions. Axial and circumferential oriented adventitia, media, and full thickness specimens were prepared from six human carotid arteries (total tissue strips: 71). Each artery yielded 12 specimens with two specimens in each of the following six categories; axial full thickness, axial adventitia (AA), axial media (AM), circumferential full thickness, circumferential adventitia (CA), and circumferential media (CM). Uniaxial testing was performed using Inspec 2200 controlled by software developed using labview. The mean stiffness of the adventitia was 3570 ± 667 and 2960 ± 331 kPa in the axial and circumferential directions, respectively, while the corresponding values for the media were 1070 ± 186 and 1800 ± 384 kPa. The adventitia was significantly stiffer than the media in both the axial (p = 0.003) and circumferential (p = 0.010) directions. The stiffness of the full thickness specimens was nearly identical in the axial (1540 ± 186) and circumferential (1530 ± 389 kPa) directions. The differences in axial and circumferential stiffness of media and adventitia were not statistically significant.
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Affiliation(s)
- Allen H Hoffman
- Mechanical Engineering Department, Worcester Polytechnic Institute, Worcester, MA 01609
| | - Zhongzhao Teng
- Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, MA 01609.,Department of Radiology, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Jie Zheng
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110
| | - Zheyang Wu
- Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, MA 01609
| | - Pamela K Woodard
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110
| | - Kristen L Billiar
- Biomedical Engineering Department, Worcester Polytechnic Institute, Worcester, MA 01609
| | - Liang Wang
- School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Dalin Tang
- School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China.,Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, MA 01609 e-mail:
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13
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Liu X, Wu G, Xu C, He Y, Shu L, Liu Y, Zhang N, Lin C. Prediction of coronary plaque progression using biomechanical factors and vascular characteristics based on computed tomography angiography. Comput Assist Surg (Abingdon) 2017; 22:286-294. [PMID: 29032716 DOI: 10.1080/24699322.2017.1389407] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVES Coronary atherosclerotic plaques progress in a highly individual manner. Accurately predicting plaque progression will promote clinical management of atherosclerosis. The purpose of this study was to investigate the role of local biomechanics factors and vascular characteristics in coronary plaque progression and arterial remodeling. METHODS Computed tomography angiography-based three-dimensional reconstruction of the native right coronary artery was performed in vivo in twelve patients with acute coronary syndrome at baseline and 12-month follow-up. The reconstructed arteries were divided into sequential 3-mm-long segments. Wall shear stress (WSS) and von Mises stress (VMS) were computed in all segments at baseline by applying fluid-structure interaction simulations. RESULTS In total, 365 segments 3-mm long were analyzed. The decrease in minimal lumen area was independently predicted by low baseline VMS (-0.73 ± 0.13 mm2), increase in plaque burden was independently predicted by small minimal lumen area and low baseline WSS (6.28 ± 0.96%), and decrease in plaque volume was independently predicted by low baseline VMS (-0.99 ± 0.49 mm3). Negative remodeling was more likely to occur in low- (55%) and moderate-VMS (40%) segments, but expansive remodeling was more likely to occur in high-VMS (44%) segments. CONCLUSIONS Local von Mises stress, wall shear stress, minimal lumen area, and plaque burden provide independent and additive prediction in identifying coronary plaque progression and arterial remodeling.
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Affiliation(s)
- Xiujian Liu
- a Beijing Institute of Heart, Lung, and Blood Vessel Diseases , Beijing Anzhen Hospital, Capital Medical University , Beijing , China
| | - Guanghui Wu
- a Beijing Institute of Heart, Lung, and Blood Vessel Diseases , Beijing Anzhen Hospital, Capital Medical University , Beijing , China
| | - Chuangye Xu
- a Beijing Institute of Heart, Lung, and Blood Vessel Diseases , Beijing Anzhen Hospital, Capital Medical University , Beijing , China
| | - Yuna He
- a Beijing Institute of Heart, Lung, and Blood Vessel Diseases , Beijing Anzhen Hospital, Capital Medical University , Beijing , China
| | - Lixia Shu
- a Beijing Institute of Heart, Lung, and Blood Vessel Diseases , Beijing Anzhen Hospital, Capital Medical University , Beijing , China
| | - Yuyang Liu
- a Beijing Institute of Heart, Lung, and Blood Vessel Diseases , Beijing Anzhen Hospital, Capital Medical University , Beijing , China
| | - Nan Zhang
- a Beijing Institute of Heart, Lung, and Blood Vessel Diseases , Beijing Anzhen Hospital, Capital Medical University , Beijing , China
| | - Changyan Lin
- a Beijing Institute of Heart, Lung, and Blood Vessel Diseases , Beijing Anzhen Hospital, Capital Medical University , Beijing , China
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14
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Onaizah O, Poepping TL, Zamir M. A model of blood supply to the brain via the carotid arteries: Effects of obstructive vs. sclerotic changes. Med Eng Phys 2017; 49:121-130. [PMID: 28917828 DOI: 10.1016/j.medengphy.2017.08.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 05/31/2017] [Accepted: 08/18/2017] [Indexed: 10/18/2022]
Abstract
The carotid artery is one of the major supply routes of blood to the brain and a common site of vascular disease. Obstructive and sclerotic disorders within the carotid artery impact local blood flow patterns as well as overall impedance and blood supply to the brain. A lumped parameter model and an experimental in-vitro flow loop were used to study the effects of local stenosis and stiffness in the carotid artery based on a family of phantoms with different degrees of stenosis and compliance. The model also allows independent examination of the effects of downstream resistance and compliance. Mild to moderate stenosis was found to lead to minimal (∼1%) reduction in blood supply to the brain. Reduction in mean internal carotid artery (ICA) flow was statistically significant (p< 0.01) only above 70% stenosis. On the other hand, a three-fold increase in stiffness of the carotid artery, as might occur in aging, was found to lead to a modest yet statistically significant reduction (p< 0.01) in mean ICA flow. Effects of changing downstream resistance and compliance were examined. For a given pressure waveform, reduction in downstream compliance led to altered waveform shape and reduction in peak systolic flow rates where the mean flow rates were not altered. Increased downstream resistance resulted in drastic reduction in mean flow rates.
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Affiliation(s)
- O Onaizah
- Department of Medical Biophysics, The University of Western Ontario, London, Canada
| | - T L Poepping
- Department of Medical Biophysics, The University of Western Ontario, London, Canada; Department of Physics and Astronomy, The University of Western Ontario, London, Canada
| | - M Zamir
- Department of Applied Mathematics, The University of Western Ontario, London, Canada; Department of Medical Biophysics, The University of Western Ontario, London, Canada.
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15
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Choi W, Park SH, Huh HK, Lee SJ. Hemodynamic characteristics of flow around a deformable stenosis. J Biomech 2017; 61:216-223. [PMID: 28835343 DOI: 10.1016/j.jbiomech.2017.07.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 06/06/2017] [Accepted: 07/22/2017] [Indexed: 10/19/2022]
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16
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Three-dimensional black-blood T 2 mapping with compressed sensing and data-driven parallel imaging in the carotid artery. Magn Reson Imaging 2017; 37:62-69. [DOI: 10.1016/j.mri.2016.11.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 11/18/2016] [Accepted: 11/20/2016] [Indexed: 11/22/2022]
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17
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Douglas GR, Brown AJ, Gillard JH, Bennett MR, Sutcliffe MPF, Teng Z. Impact of Fiber Structure on the Material Stability and Rupture Mechanisms of Coronary Atherosclerotic Plaques. Ann Biomed Eng 2017; 45:1462-1474. [PMID: 28361184 PMCID: PMC5415591 DOI: 10.1007/s10439-017-1827-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 03/22/2017] [Indexed: 12/19/2022]
Abstract
The rupture of an atherosclerotic plaque in the coronary circulation remains the main cause of heart attack. As a fiber-oriented structure, the fiber structure, in particular in the fibrous cap (FC), may affect both loading and material strength in the plaque. However, the role of fiber orientation and dispersion in plaque rupture is unclear. Local orientation and dispersion of fibers were calculated for the shoulder regions, mid FC, and regions with intimal thickening (IT) from histological images of 16 human coronary atherosclerotic lesions. Finite element analysis was performed to assess the effect of these properties on mechanical conditions. Fibers in shoulder regions had markedly reduced alignment (Median [interquartile range] 12.9° [6.6, 18.0], p < 0.05) compared with those in mid FC (6.1° [5.5, 9.0]) and IT regions (6.7° [5.1, 8.6]). Fiber dispersion was highest in shoulders (0.150 [0.121, 0.192]), intermediate in IT (0.119 [0.103, 0.144]), and lowest in mid FC regions (0.093 [0.081, 0.105], p < 0.05). When anisotropic properties were considered, stresses were significantly higher for the mid FC (p = 0.030) and IT regions (p = 0.002) and no difference was found for the shoulder or global regions. Shear (sliding) stress between fibers in each region and their proportion of maximum principal stress were: shoulder (25.8 kPa [17.1, 41.2], 12.4%), mid FC (13.9 kPa [5.8, 29.6], 13.8%), and IT (36.5 kPa [25.9, 47.3], 15.5%). Fiber structure within the FC has a marked effect on principal stresses, resulting in considerable shear stress between fibers. Fiber structure including orientation and dispersion may determine mechanical strength and thus rupture of atherosclerotic plaques.
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Affiliation(s)
- Graeham R Douglas
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, CB2 1PZ, UK
| | - Adam J Brown
- Division of Cardiovascular Medicine, University of Cambridge, Cambridge, UK
| | - Jonathan H Gillard
- Department of Radiology, School of Clinical Medicine, University of Cambridge, Box 218, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK
| | - Martin R Bennett
- Division of Cardiovascular Medicine, University of Cambridge, Cambridge, UK
| | - Michael P F Sutcliffe
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, CB2 1PZ, UK.
| | - Zhongzhao Teng
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, CB2 1PZ, UK. .,Department of Radiology, School of Clinical Medicine, University of Cambridge, Box 218, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK.
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18
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Magnetic Resonance Imaging-Based Assessment of Carotid Atheroma: a Comparative Study of Patients with and without Coronary Artery Disease. J Stroke Cerebrovasc Dis 2017; 26:347-351. [DOI: 10.1016/j.jstrokecerebrovasdis.2016.09.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 07/24/2016] [Accepted: 09/15/2016] [Indexed: 11/21/2022] Open
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19
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Jia Q, Liu H, Li Y, Wang X, Jia J, Li Y. Combination of Magnetic Resonance Angiography and Computational Fluid Dynamics May Predict the Risk of Stroke in Patients with Asymptomatic Carotid Plaques. Med Sci Monit 2017; 23:479-488. [PMID: 28126983 PMCID: PMC5292986 DOI: 10.12659/msm.902995] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Background Atherosclerosis plaques in the carotid arteries frequently have been found in patients with stroke. However, the pathogenesis of carotid plaque from asymptomatic to cerebrovascular events is a complex process which is still not completely understood. We aimed to investigate the prognosis of asymptomatic carotid atherosclerotic plaques by use of magnetic resonance angiography (MRA) combined with computational fluid dynamics (CFD). Material/Methods We prospectively studied a cohort of 228 participants (mean age 59.21±8.48) with asymptomatic carotid atherosclerotic plaques; mean follow-up duration was 1147.56±224.84 days. Plaque morphology parameters were obtained by MRA analysis. Lumen area (LA) and total vessel area (TVA) were measured, and wall area (WA=TVA−LA) and normalized wall area index (NWI=WA/TVA) were calculated. CFD analysis was performed to evaluate hemodynamic characteristics, including wall pressure (WP) and wall shear stress (WSS). Independent risk factors for stroke were obtained by Cox regression analysis. The area under the curve (AUC) of receiver operator characteristic (ROC) and Z-statistic test were used to evaluate risk factors. Results Logistics regression analysis showed NWI (OR: 3.472, 95% CI: 2.943–4.096, P=0.11) and WSS (OR: 6.974, 95% CI: 1.070–45.453, P=0.42) were independent risk factors of stroke for patients with asymptomatic carotid plaques. The area under the ROC curve values for WSS, NWI, and WSS+NWI were 0.772, 0.798, and 0.903, respectively. Conclusions The combination of plaque morphology characteristics NWI and hemodynamic parameter WSS may predict the risk of stroke in patients with asymptomatic carotid plaques.
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Affiliation(s)
- Qian Jia
- Second Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing, China (mainland).,Department of Cardiology, School of Medicine, Nankai University, Tianjin, China (mainland)
| | - Hongbin Liu
- Second Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing, China (mainland)
| | - Yanping Li
- Second Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing, China (mainland).,Outpatient Department of North China Military Materials Procurement Bureau, Tianjin, China (mainland)
| | - Xiaoxi Wang
- Second Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing, China (mainland)
| | - Jinju Jia
- Department of Cardiology, Jizhong Energy Xingtai Mig General Hospital, Xingtai, Hebei, China (mainland)
| | - Yuying Li
- Department of Radiology, Chinese PLA General Hospital, Beijing, China (mainland)
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20
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Yuan J, Usman A, Das T, Patterson AJ, Gillard JH, Graves MJ. Imaging Carotid Atherosclerosis Plaque Ulceration: Comparison of Advanced Imaging Modalities and Recent Developments. AJNR Am J Neuroradiol 2016; 38:664-671. [PMID: 28007772 DOI: 10.3174/ajnr.a5026] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Atherosclerosis remains the leading cause of long-term mortality and morbidity worldwide, despite remarkable advancement in its management. Vulnerable atherosclerotic plaques are principally responsible for thromboembolic events in various arterial territories such as carotid, coronary, and lower limb vessels. Carotid plaque ulceration is one of the key features associated with plaque vulnerability and is considered a notable indicator of previous plaque rupture and possible future cerebrovascular events. Multiple imaging modalities have been used to assess the degree of carotid plaque ulceration for diagnostic and research purposes. Early diagnosis and management of carotid artery disease could prevent further cerebrovascular events. In this review, we highlight the merits and limitations of various imaging techniques for identifying plaque ulceration.
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Affiliation(s)
- J Yuan
- From the Department of Radiology (J.Y., A.U., J.H.G., M.J.G.), University of Cambridge, Cambridge, UK
| | - A Usman
- From the Department of Radiology (J.Y., A.U., J.H.G., M.J.G.), University of Cambridge, Cambridge, UK
| | - T Das
- Department of Radiology (T.D., A.J.P., M.J.G.), Cambridge University Hospitals National Health Service Foundation Trust, Cambridge, UK
| | - A J Patterson
- Department of Radiology (T.D., A.J.P., M.J.G.), Cambridge University Hospitals National Health Service Foundation Trust, Cambridge, UK
| | - J H Gillard
- From the Department of Radiology (J.Y., A.U., J.H.G., M.J.G.), University of Cambridge, Cambridge, UK
| | - M J Graves
- From the Department of Radiology (J.Y., A.U., J.H.G., M.J.G.), University of Cambridge, Cambridge, UK.,Department of Radiology (T.D., A.J.P., M.J.G.), Cambridge University Hospitals National Health Service Foundation Trust, Cambridge, UK
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21
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Stress analysis of fracture of atherosclerotic plaques: crack propagation modeling. Med Biol Eng Comput 2016; 55:1389-1400. [DOI: 10.1007/s11517-016-1600-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 11/28/2016] [Indexed: 12/19/2022]
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22
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Zhao XQ, Yuan C, Shah PK. Imaging to Assess the Effect of Anti-Inflammatory Therapy in Aortic and Carotid Atherosclerosis. J Am Coll Cardiol 2016; 68:1781-1784. [PMID: 27737745 DOI: 10.1016/j.jacc.2016.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 08/14/2016] [Indexed: 10/20/2022]
Affiliation(s)
- Xue-Qiao Zhao
- Department of Cardiology, University of Washington, Seattle, Washington
| | - Chun Yuan
- Department of Radiology, University of Washington, Seattle, Washington.
| | - Prediman K Shah
- Department of Medicine, Cedars-Sinai Heart Institute, West Hollywood, California
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23
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Jiang Y, Peng W, Teng Z, Gillard JH, Hong B, Liu Q, Lu J. Local blood pressure associates with the degree of luminal stenosis in patients with atherosclerotic disease in the middle cerebral artery. Biomed Eng Online 2016; 15:67. [PMID: 27349223 PMCID: PMC4924238 DOI: 10.1186/s12938-016-0202-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 06/21/2016] [Indexed: 11/10/2022] Open
Abstract
The mechanism underlying atherosclerotic ischemic events within the middle cerebral artery (MCA) is unclear. High structural stress induced by blood pressure might be a potential aetiology as plaque rupture occurs when such mechanical loading exceeds its material strength. To perform reliable analyses quantifying the mechanical loading within a plaque, the local blood pressure is needed. However, data on MCA blood pressure is currently lacking. In this study, the arterial pressure proximal to the stenotic site in the MCA was measured in 15 patients scheduled for intervention. The relationships between these local measurements and pre-intervention and intra-intervention non-invasive arm measurements were assessed. The impact of luminal stenosis on the local blood pressure was quantified. Compared with the pre-intervention arm measurement, the intra-intervention arm pressure decreased significantly by 23.9 ± 11.8 and 9.3 ± 14.7 % at diastole and systole, respectively. The pressure proximal to the stenosis was much lower than the pre-intervention arm measurement (diastole: 65.3 ± 15.7 vs 82.0 ± 9.7, p < 0.01; systole: 81.1 ± 15.9 vs 133.9 ± 18.7, p < 0.01; unit: mmHg). The systolic pressure in the MCA in patients with stenosis <70 % (n = 6) was significantly higher than the value in patients with stenosis ≥70 % (n = 9) (92.0 ± 7.3 vs 73.9 ± 16.1, p = 0.02; unit: mmHg), as was pulse pressure (22.8 ± 6.4 vs 11.1 ± 8.3, p = 0.01; unit: mmHg). However, diastolic pressure remained unaffected (69.2 ± 9.3 vs 62.8 ± 19.0, p = 0.58; unit: mmHg). In conclusion, the obtained results are helpful in understanding the local hemodynamic environment modulated by the presence of atherosclerosis. The local pressure measurements can be used for computational analysis to quantify the critical mechanical condition within an MCA lesion.
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Affiliation(s)
- Yuanliang Jiang
- Department of Radiology, Changhai Hospital, Shanghai, 200433, China
| | - Wenjia Peng
- Department of Radiology, Changhai Hospital, Shanghai, 200433, China.,Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Box 218, Cambridge, CB2 0QQ, UK
| | - Zhongzhao Teng
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Box 218, Cambridge, CB2 0QQ, UK. .,Department of Engineering, University of Cambridge, Cambridge, UK.
| | - Jonathan H Gillard
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Box 218, Cambridge, CB2 0QQ, UK
| | - Bo Hong
- Department of Neurosurgery, Changhai Hospital, Shanghai, China
| | - Qi Liu
- Department of Radiology, Changhai Hospital, Shanghai, 200433, China
| | - Jianping Lu
- Department of Radiology, Changhai Hospital, Shanghai, 200433, China.
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24
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Abstract
Atherosclerosis remains a major cause of morbidity and mortality worldwide, and a thorough understanding of the underlying pathophysiological mechanisms is crucial for the development of new therapeutic strategies. Although atherosclerosis is a systemic inflammatory disease, coronary atherosclerotic plaques are not uniformly distributed in the vascular tree. Experimental and clinical data highlight that biomechanical forces, including wall shear stress (WSS) and plaque structural stress (PSS), have an important role in the natural history of coronary atherosclerosis. Endothelial cell function is heavily influenced by changes in WSS, and longitudinal animal and human studies have shown that coronary regions with low WSS undergo increased plaque growth compared with high WSS regions. Local alterations in WSS might also promote transformation of stable to unstable plaque subtypes. Plaque rupture is determined by the balance between PSS and material strength, with plaque composition having a profound effect on PSS. Prospective clinical studies are required to ascertain whether integrating mechanical parameters with medical imaging can improve our ability to identify patients at highest risk of rapid disease progression or sudden cardiac events.
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25
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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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26
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From Ultrasonography to High Resolution Magnetic Resonance Imaging: Towards an Optimal Management Strategy for Vulnerable Carotid Atherosclerotic Plaques. EBioMedicine 2016; 3:2-3. [PMID: 26870831 PMCID: PMC4739411 DOI: 10.1016/j.ebiom.2016.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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27
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Yao B, Yang L, Wang G, Shi H, Wang S, Li H, Chen W, Chan Q. Diffusion measurement of intraplaque hemorrhage and intramural hematoma using diffusion weighted MRI at 3T in cervical artery. Eur Radiol 2015; 26:3737-43. [PMID: 26670319 DOI: 10.1007/s00330-015-4149-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 11/26/2015] [Accepted: 11/30/2015] [Indexed: 01/01/2023]
Affiliation(s)
- Bin Yao
- The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, Jiangxi, China
| | - Li Yang
- Department of Radiology, Shanghai Institute of Medical Imaging, Zhongshan Hospital, Fudan University, Shanghai, 200032, People's Republic of China
| | - Guangbin Wang
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, 250021, Shandong, People's Republic of China.
| | - Honglu Shi
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, 250021, Shandong, People's Republic of China
| | - Shanshan Wang
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, 250021, Shandong, People's Republic of China
| | - Huihua Li
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, 250021, Shandong, People's Republic of China
| | - Weibo Chen
- Philips Healthcare, Shanghai, People's Republic of China
| | - Queenie Chan
- Philips Healthcare, Shanghai, People's Republic of China
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28
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Teng Z, Feng J, Zhang Y, Sutcliffe MPF, Huang Y, Brown AJ, Jing Z, Lu Q, Gillard JH. A uni-extension study on the ultimate material strength and extreme extensibility of atherosclerotic tissue in human carotid plaques. J Biomech 2015; 48:3859-67. [PMID: 26472304 PMCID: PMC4655866 DOI: 10.1016/j.jbiomech.2015.09.037] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 09/16/2015] [Accepted: 09/24/2015] [Indexed: 12/26/2022]
Abstract
Atherosclerotic plaque rupture occurs when mechanical loading exceeds its material strength. Mechanical analysis has been shown to be complementary to the morphology and composition for assessing vulnerability. However, strength and stretch thresholds for mechanics-based assessment are currently lacking. This study aims to quantify the ultimate material strength and extreme extensibility of atherosclerotic components from human carotid plaques. Tissue strips of fibrous cap, media, lipid core and intraplaque hemorrhage/thrombus were obtained from 21 carotid endarterectomy samples of symptomatic patients. Uni-extension test with tissue strips was performed until they broke or slid. The Cauchy stress and stretch ratio at the peak loading of strips broken about 2 mm away from the clamp were used to characterize their ultimate strength and extensibility. Results obtained indicated that ultimate strength of fibrous cap and media were 158.3 [72.1, 259.3] kPa (Median [Inter quartile range]) and 247.6 [169.0, 419.9] kPa, respectively; those of lipid and intraplaque hemorrhage/thrombus were 68.8 [48.5, 86.6] kPa and 83.0 [52.1, 124.9] kPa, respectively. The extensibility of each tissue type were: fibrous cap – 1.18 [1.10, 1.27]; media – 1.21 [1.17, 1.32]; lipid – 1.25 [1.11, 1.30] and intraplaque hemorrhage/thrombus – 1.20 [1.17, 1.44]. Overall, the strength of fibrous cap and media were comparable and so were lipid and intraplaque hemorrhage/thrombus. Both fibrous cap and media were significantly stronger than either lipid or intraplaque hemorrhage/thrombus. All atherosclerotic components had similar extensibility. Moreover, fibrous cap strength in the proximal region (closer to the heart) was lower than that of the distal. These results are helpful in understanding the material behavior of atherosclerotic plaques.
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Affiliation(s)
- Zhongzhao Teng
- Department of Radiology, University of Cambridge, UK; Department of Engineering, University of Cambridge, UK.
| | - Jiaxuan Feng
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
| | - Yongxue Zhang
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
| | | | - Yuan Huang
- Department of Radiology, University of Cambridge, UK
| | - Adam J Brown
- Division of Cardiovascular Medicine, University of Cambridge, UK
| | - Zaiping Jing
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
| | - Qingsheng Lu
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
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Teng Z, Yuan J, Feng J, Zhang Y, Brown AJ, Wang S, Lu Q, Gillard JH. The influence of constitutive law choice used to characterise atherosclerotic tissue material properties on computing stress values in human carotid plaques. J Biomech 2015; 48:3912-21. [PMID: 26472305 PMCID: PMC4655867 DOI: 10.1016/j.jbiomech.2015.09.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 09/16/2015] [Accepted: 09/24/2015] [Indexed: 01/01/2023]
Abstract
Calculating high stress concentration within carotid atherosclerotic plaques has been shown to be complementary to anatomical features in assessing vulnerability. Reliability of stress calculation may depend on the constitutive laws/strain energy density functions (SEDFs) used to characterize tissue material properties. Different SEDFs, including neo-Hookean, one-/two-term Ogden, Yeoh, 5-parameter Mooney–Rivlin, Demiray and modified Mooney–Rivlin, have been used to describe atherosclerotic tissue behavior. However, the capacity of SEDFs to fit experimental data and the difference in the stress calculation remains unexplored. In this study, seven SEDFs were used to fit the stress–stretch data points of media, fibrous cap, lipid and intraplaque hemorrhage/thrombus obtained from 21 human carotid plaques. Semi-analytic solution, 2D structure-only and 3D fully coupled fluid-structure interaction (FSI) analyses were used to quantify stress using different SEDFs and the related material stability examined. Results show that, except for neo-Hookean, all other six SEDFs fitted the experimental points well, with vessel stress distribution in the circumferential and radial directions being similar. 2D structural-only analysis was successful for all seven SEDFs, but 3D FSI were only possible with neo-Hookean, Demiray and modified Mooney–Rivlin models. Stresses calculated using Demiray and modified Mooney–Rivlin models were nearly identical. Further analyses indicated that the energy contours of one-/two-term Ogden and 5-parameter Mooney–Rivlin models were not strictly convex and the material stability indictors under homogeneous deformations were not always positive. In conclusion, considering the capacity in characterizing material properties and stabilities, Demiray and modified Mooney–Rivlin SEDF appear practical choices for mechanical analyses to predict the critical mechanical conditions within carotid atherosclerotic plaques.
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Affiliation(s)
- Zhongzhao Teng
- Department of Radiology, University of Cambridge, UK; Department of Engineering, University of Cambridge, UK.
| | - Jianmin Yuan
- Department of Radiology, University of Cambridge, UK
| | - Jiaxuan Feng
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
| | - Yongxue Zhang
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
| | - Adam J Brown
- Division of Cardiovascular Medicine, University of Cambridge, UK
| | - Shuo Wang
- Department of Radiology, University of Cambridge, UK
| | - Qingsheng Lu
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
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An assessment on the incremental value of high-resolution magnetic resonance imaging to identify culprit plaques in atherosclerotic disease of the middle cerebral artery. Eur Radiol 2015; 26:2206-14. [PMID: 26376883 PMCID: PMC4902836 DOI: 10.1007/s00330-015-4008-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 07/31/2015] [Accepted: 09/03/2015] [Indexed: 11/11/2022]
Abstract
Objective Although certain morphological features depicted by high resolution, multi-contrast magnetic resonance imaging (hrMRI) have been shown to be different between culprit and non-culprit middle cerebral artery (MCA) atherosclerotic lesions, the incremental value of hrMRI to define culprit lesions over stenosis has not been assessed. Methods Patients suspected with MCA stenosis underwent hrMRI. Lumen and outer wall were segmented to calculate stenosis, plaque burden (PB), volume (PV), length (PL) and minimum luminal area (MLA). Results Data from 165 lesions (112 culprit and 53 non-culprit) in 139 individuals were included. Culprit lesions were larger and longer with a narrower lumen and increased PB compared with non-culprit lesions. More culprit lesions showed contrast enhancement. Both PB and MLA were better indicators than stenosis in differentiating lesion types (AUC were 0.649, 0.732 and 0.737 for stenosis, PB and MLA, respectively). Combinations of PB, MLA and stenosis could improve positive predictive value (PPV) and specificity significantly. An optimal combination of stenosis ≥ 50 %, PB ≥ 77 % and MLA ≤ 2.0 mm2 produced a PPV = 85.7 %, negative predictive value = 54.1 %, sensitivity = 69.6 %, specificity = 75.5 %, and accuracy = 71.5 %. Conclusions hrMRI plaque imaging provides incremental information to luminal stenosis in identifying culprit lesions. Key points • High resolution MRI provides incremental information in defining culprit MCA atherosclerotic lesions. • Both plaque burden and minimum luminal area are better indicators than stenosis. • An optimal combination includes stenosis ≥ 50 %, PB ≥ 77 % and MLA ≤ 2.0 mm2. Electronic supplementary material The online version of this article (doi:10.1007/s00330-015-4008-5) contains supplementary material, which is available to authorized users.
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Usman A, Sadat U, Graves MJ, Gillard JH. Magnetic resonance imaging of atherothrombotic plaques. J Clin Neurosci 2015; 22:1722-6. [PMID: 26254092 DOI: 10.1016/j.jocn.2015.03.060] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 03/28/2015] [Indexed: 11/27/2022]
Abstract
Atherosclerosis remains the leading cause of long term morbidity and mortality worldwide, despite significant advances in its management. Vulnerable atherothrombotic plaques are predominantly responsible for thromboembolic ischaemic events in arterial beds, such as the carotid, coronary and lower limb arteries. MRI has emerged as a non-invasive, non-irradiating and highly reproducible imaging technique which allows detailed morphological and functional assessment of such plaques. It also has the potential to monitor the efficacy of established and evolving anti-atherosclerosis drugs. It is envisaged that by careful identification and understanding of the underlying cellular and molecular mechanisms that govern atherosclerosis, novel treatment strategies can be formulated which may reduce the persistent high mortality and morbidity rates associated with this disease. MRI shows promise in achieving this goal.
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Affiliation(s)
- Ammara Usman
- University Department of Radiology, Addenbrooke's Hospital, Post Office Box 218, Level 5, Hills Road, Cambridge CB20QQ, UK.
| | - Umar Sadat
- Cambridge Vascular Unit, Cambridge University Hospitals National Health Service Foundation Trust, Cambridge, UK
| | - Martin J Graves
- University Department of Radiology, Addenbrooke's Hospital, Post Office Box 218, Level 5, Hills Road, Cambridge CB20QQ, UK
| | - Jonathan H Gillard
- University Department of Radiology, Addenbrooke's Hospital, Post Office Box 218, Level 5, Hills Road, Cambridge CB20QQ, UK
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Yuan J, Teng Z, Feng J, Zhang Y, Brown AJ, Gillard JH, Jing Z, Lu Q. Influence of material property variability on the mechanical behaviour of carotid atherosclerotic plaques: a 3D fluid-structure interaction analysis. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2015; 31:e02722. [PMID: 25940741 PMCID: PMC4528233 DOI: 10.1002/cnm.2722] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 03/10/2015] [Accepted: 04/27/2015] [Indexed: 06/04/2023]
Abstract
Mechanical analysis has been shown to be complementary to luminal stenosis in assessing atherosclerotic plaque vulnerability. However, patient-specific material properties are not available and the effect of material properties variability has not been fully quantified. Media and fibrous cap (FC) strips from carotid endarterectomy samples were classified into hard, intermediate and soft according to their incremental Young's modulus. Lipid and intraplaque haemorrhage/thrombus strips were classified as hard and soft. Idealised geometry-based 3D fluid-structure interaction analyses were performed to assess the impact of material property variability in predicting maximum principal stress (Stress-P1 ) and stretch (Stretch-P1 ). When FC was thick (1000 or 600 µm), Stress-P1 at the shoulder was insensitive to changes in material stiffness, whereas Stress-P1 at mid FC changed significantly. When FC was thin (200 or 65 µm), high stress concentrations shifted from the shoulder region to mid FC, and Stress-P1 became increasingly sensitive to changes in material properties, in particular at mid FC. Regardless of FC thickness, Stretch-P1 at these locations was sensitive to changes in material properties. Variability in tissue material properties influences both the location and overall stress/stretch value. This variability needs to be accounted for when interpreting the results of mechanical modelling.
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Affiliation(s)
- Jianmin Yuan
- Department of Radiology, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Zhongzhao Teng
- Department of Radiology, University of Cambridge, Cambridge, CB2 0QQ, UK
- Department of Engineering, University of Cambridge, Cambridge, CB2 1PZ, UK
| | - Jiaxuan Feng
- Department of Vascular Surgery, Changhai Hospital, Changhai Road, Shanghai, 200433, China
| | - Yongxue Zhang
- Department of Radiology, University of Cambridge, Cambridge, CB2 0QQ, UK
- Department of Vascular Surgery, Changhai Hospital, Changhai Road, Shanghai, 200433, China
| | - Adam J Brown
- Division of Cardiovascular Medicine, University of Cambridge, Cambridge, CB2 1TN, UK
| | - Jonathan H Gillard
- Department of Radiology, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Zaiping Jing
- Department of Vascular Surgery, Changhai Hospital, Changhai Road, Shanghai, 200433, China
| | - Qingsheng Lu
- Department of Vascular Surgery, Changhai Hospital, Changhai Road, Shanghai, 200433, China
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Gupta A, Marshall RS. Moving beyond luminal stenosis: imaging strategies for stroke prevention in asymptomatic carotid stenosis. Cerebrovasc Dis 2015; 39:253-61. [PMID: 25870952 DOI: 10.1159/000381108] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 02/17/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND With progressive improvements in medical therapy and resultant reductions in stroke risk, luminal stenosis criteria are no longer adequate to inform decisions to pursue surgical revascularization in patients with asymptomatic carotid artery stenosis. SUMMARY In this evidence-based review, we discuss the imaging-based risk stratification strategies that take into account factors beyond luminal stenosis measurements, including cerebral hemodynamics and plaque composition. The existing literature lends support to the use of certain imaging tests in patients with asymptomatic carotid stenosis including cerebrovascular reserve testing, MRI of plaque composition, ultrasound of plaque echolucency, and transcranial Doppler evaluation for microemboli. The highest quality evidence thus far in the literature includes only systematic reviews and meta-analyses of cohort studies with no randomized trials having yet been performed to show how these newer imaging biomarkers could be used to inform treatment decisions in asymptomatic carotid stenosis. Beyond the need for randomized trials, there are additional important steps needed to improve the relevance of evidence supporting risk assessment strategies. Imaging studies evaluating the risk of stroke in carotid disease should clearly define asymptomatic versus symptomatic disease, use uniform definitions of clearly defined outcome measures such as ipsilateral stroke, ensure that imaging interpretations are performed in a manner blinded to treatments and other risk factors, and include cohorts which are on modern intensive medical therapy. Such studies of risk stratification for asymptomatic carotid stenosis will be most valuable if they can integrate multiple high-risk features (including clinical risk factors) into a multi-factorial risk assessment strategy in a manner that is relatively simple to implement and generalizable across a wide range of practice settings. Key Messages: Together, modern imaging strategies allow for a more mechanistic assessment of stroke risk in carotid disease compared to luminal stenosis measurements alone, which, with further validation in randomized controlled trials, may improve current efforts at stroke prevention in asymptomatic carotid stenosis.
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Affiliation(s)
- Ajay Gupta
- Department of Radiology, Weill Cornell Medical College, New York, N.Y., USA
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Makris GC, Teng Z, Patterson AJ, Lin JM, Young V, Graves MJ, Gillard JH. Advances in MRI for the evaluation of carotid atherosclerosis. Br J Radiol 2015; 88:20140282. [PMID: 25826233 DOI: 10.1259/bjr.20140282] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Carotid artery atherosclerosis is an important source of mortality and morbidity in the Western world with significant socioeconomic implications. The quest for the early identification of the vulnerable carotid plaque is already in its third decade and traditional measures, such as the sonographic degree of stenosis, are not selective enough to distinguish those who would really benefit from a carotid endarterectomy. MRI of the carotid plaque enables the visualization of plaque composition and specific plaque components that have been linked to a higher risk of subsequent embolic events. Blood suppressed T1 and T2 weighted and proton density-weighted fast spin echo, gradient echo and time-of-flight sequences are typically used to quantify plaque components such as lipid-rich necrotic core, intraplaque haemorrhage, calcification and surface defects including erosion, disruption and ulceration. The purpose of this article is to review the most important recent advances in MRI technology to enable better diagnostic carotid imaging.
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Affiliation(s)
- G C Makris
- Department of Radiology, University of Cambridge, Cambridge, UK
| | - Z Teng
- Department of Radiology, University of Cambridge, Cambridge, UK
| | - A J Patterson
- Department of Radiology, University of Cambridge, Cambridge, UK
| | - J-M Lin
- Department of Radiology, University of Cambridge, Cambridge, UK
| | - V Young
- Department of Radiology, University of Cambridge, Cambridge, UK
| | - M J Graves
- Department of Radiology, University of Cambridge, Cambridge, UK
| | - J H Gillard
- Department of Radiology, University of Cambridge, Cambridge, UK
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The application of ultrasonic velocity vector imaging technique of carotid plaque in predicting large-artery atherosclerotic stroke. J Stroke Cerebrovasc Dis 2015; 24:1351-6. [PMID: 25797431 DOI: 10.1016/j.jstrokecerebrovasdis.2015.02.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 02/09/2015] [Accepted: 02/11/2015] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Large-artery atherosclerotic stroke (LAAs) is related to carotid plaque, but the mechanical mechanism is unclear. We aimed to use ultrasonic velocity vector imaging (VVI) technique to study the mechanical difference of carotid plaque in patients with LAAs and controls. METHODS We enrolled 43 LAAs patients and 38 controls but all showing plaque on carotid ultrasonography. Ultrasonic VVI technique was used to analyze radial systolic and diastolic peak velocity (R-vs, R-vd), radial and circumferential peak strain (R-s, C-s) and radial displacement (R-dis) of carotid plaque. RESULTS Compared with controls, LAAs patients showed higher pulse pressure (P = .001), pulse pressure index (PPI, P = .006), and greater stress at carotid plaque as manifested by higher absolute value of radial diastolic peak velocity (R-vd, P = .021), radial systolic peak velocity (R-vs, P = .007), radial peak strain (R-s, P = .015), and radial displacement (R-dis, P = .022). PPI was significantly correlated with R-vs (r = -.274, P = .013), R-vd (r = .304, P = .006), and R-dis (r = -.28, P = .011). But there was no correlation between R-s and blood pressure. R-s was screened to be the most predictable parameters for LAAs (odds ratio, 1.118; 95% confidence interval, 1.012∼1.236; P = .029). The area under the curve of R-s was .627. CONCLUSIONS Radial peak strain (R-s) is a predictable parameter for the occurrence of LAAs. We predict using ultrasonic VVI technique to analyze whether the mechanics of carotid plaque is helpful to screen patients with high risks of LAAs.
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Material properties of components in human carotid atherosclerotic plaques: a uniaxial extension study. Acta Biomater 2014; 10:5055-5063. [PMID: 25200842 PMCID: PMC4226324 DOI: 10.1016/j.actbio.2014.09.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 07/31/2014] [Accepted: 09/01/2014] [Indexed: 12/17/2022]
Abstract
Computational modelling to calculate the mechanical loading within atherosclerotic plaques has been shown to be complementary to defining anatomical plaque features in determining plaque vulnerability. However, its application has been partially impeded by the lack of comprehensive knowledge about the mechanical properties of various tissues within the plaque. Twenty-one human carotid plaques were collected from endarterectomy. The plaque was cut into rings, and different type of atherosclerotic tissues, including media, fibrous cap (FC), lipid and intraplaque haemorrhage/thrombus (IPH/T) was dissected for uniaxial extension testing. In total, 65 media strips from 17 samples, 59 FC strips from 14 samples, 38 lipid strips from 11 samples, and 21 IPH/T strips from 11 samples were tested successfully. A modified Mooney–Rivlin strain energy density function was used to characterize the stretch–stress relationship. The stiffnesses of media and FC are comparable, as are lipid and IPH/T. However, both media and FC are stiffer than either lipid or IPH/T. The median values of incremental Young’s modulus of media, FC, lipid and IPH/T at λ = 1 are 290.1, 244.5, 104.4, 52.9, respectively; they increase to 1019.5, 817.4, 220.7 and 176.9 at λ = 1.1; and 4302.7, 3335.0, 533.4 and 268.8 at λ = 1.15 (unit, kPa; λ, stretch ratio). The material constants of each tissue type are suggested to be: media, c1 = 0.138 kPa, D1 = 3.833 kPa and D2 = 18.803; FC, c1 = 0.186 kPa, D1 = 5.769 kPa and D2 = 18.219; lipid, c1 = 0.046 kPa, D1 = 4.885 kPa and D2 = 5.426; and IPH/T, c1 = 0.212 kPa, D1 = 4.260 kPa and D2 = 5.312. It is concluded that all soft atherosclerotic tissues are non-linear, and both media and FC are stiffer than either lipid or IPH/T.
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Kefayati S, Milner JS, Holdsworth DW, Poepping TL. In vitro shear stress measurements using particle image velocimetry in a family of carotid artery models: effect of stenosis severity, plaque eccentricity, and ulceration. PLoS One 2014; 9:e98209. [PMID: 25007248 PMCID: PMC4090132 DOI: 10.1371/journal.pone.0098209] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 04/30/2014] [Indexed: 01/15/2023] Open
Abstract
Atherosclerotic disease, and the subsequent complications of thrombosis and plaque rupture, has been associated with local shear stress. In the diseased carotid artery, local variations in shear stress are induced by various geometrical features of the stenotic plaque. Greater stenosis severity, plaque eccentricity (symmetry) and plaque ulceration have been associated with increased risk of cerebrovascular events based on clinical trial studies. Using particle image velocimetry, the levels and patterns of shear stress (derived from both laminar and turbulent phases) were studied for a family of eight matched-geometry models incorporating independently varied plaque features - i.e. stenosis severity up to 70%, one of two forms of plaque eccentricity, and the presence of plaque ulceration). The level of laminar (ensemble-averaged) shear stress increased with increasing stenosis severity resulting in 2-16 Pa for free shear stress (FSS) and approximately double (4-36 Pa) for wall shear stress (WSS). Independent of stenosis severity, marked differences were found in the distribution and extent of shear stress between the concentric and eccentric plaque formations. The maximum WSS, found at the apex of the stenosis, decayed significantly steeper along the outer wall of an eccentric model compared to the concentric counterpart, with a 70% eccentric stenosis having 249% steeper decay coinciding with the large outer-wall recirculation zone. The presence of ulceration (in a 50% eccentric plaque) resulted in both elevated FSS and WSS levels that were sustained longer (∼20 ms) through the systolic phase compared to the non-ulcerated counterpart model, among other notable differences. Reynolds (turbulent) shear stress, elevated around the point of distal jet detachment, became prominent during the systolic deceleration phase and was widely distributed over the large recirculation zone in the eccentric stenoses.
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Affiliation(s)
- Sarah Kefayati
- Department of Physics and Astronomy, University of Western Ontario, London, ON, Canada
| | - Jaques S. Milner
- Imaging Research Laboratories, Robarts Research Institute, London, ON, Canada
| | - David W. Holdsworth
- Imaging Research Laboratories, Robarts Research Institute, London, ON, Canada
- Department of Surgery, University of Western Ontario, London, ON, Canada
| | - Tamie L. Poepping
- Department of Physics and Astronomy, University of Western Ontario, London, ON, Canada
- Imaging Research Laboratories, Robarts Research Institute, London, ON, Canada
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Huang Y, Teng Z, Sadat U, Graves MJ, Bennett MR, Gillard JH. The influence of computational strategy on prediction of mechanical stress in carotid atherosclerotic plaques: comparison of 2D structure-only, 3D structure-only, one-way and fully coupled fluid-structure interaction analyses. J Biomech 2014; 47:1465-71. [PMID: 24529358 PMCID: PMC3989027 DOI: 10.1016/j.jbiomech.2014.01.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 01/15/2014] [Accepted: 01/15/2014] [Indexed: 11/15/2022]
Abstract
BACKGROUND Compositional and morphological features of carotid atherosclerotic plaques provide complementary information to luminal stenosis in predicting clinical presentations. However, they alone cannot predict cerebrovascular risk. Mechanical stress within the plaque induced by cyclical changes in blood pressure has potential to assess plaque vulnerability. Various modeling strategies have been employed to predict stress, including 2D and 3D structure-only, 3D one-way and fully coupled fluid-structure interaction (FSI) simulations. However, differences in stress predictions using different strategies have not been assessed. METHODS Maximum principal stress (Stress-P1) within 8 human carotid atherosclerotic plaques was calculated based on geometry reconstructed from in vivo computerized tomography and high resolution, multi-sequence magnetic resonance images. Stress-P1 within the diseased region predicted by 2D and 3D structure-only, and 3D one-way FSI simulations were compared to 3D fully coupled FSI analysis. RESULTS Compared to 3D fully coupled FSI, 2D structure-only simulation significantly overestimated stress level (94.1 kPa [65.2, 117.3] vs. 85.5 kPa [64.4, 113.6]; median [inter-quartile range], p=0.0004). However, when slices around the bifurcation region were excluded, stresses predicted by 2D structure-only simulations showed a good correlation (R(2)=0.69) with values obtained from 3D fully coupled FSI analysis. 3D structure-only model produced a small yet statistically significant stress overestimation compared to 3D fully coupled FSI (86.8 kPa [66.3, 115.8] vs. 85.5 kPa [64.4, 113.6]; p<0.0001). In contrast, one-way FSI underestimated stress compared to 3D fully coupled FSI (78.8 kPa [61.1, 100.4] vs. 85.5 kPa [64.4, 113.7]; p<0.0001). CONCLUSIONS A 3D structure-only model seems to be a computationally inexpensive yet reasonably accurate approximation for stress within carotid atherosclerotic plaques with mild to moderate luminal stenosis as compared to fully coupled FSI analysis.
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Affiliation(s)
- Yuan Huang
- University Departments of Radiology, University of Cambridge, UK
| | - Zhongzhao Teng
- University Departments of Radiology, University of Cambridge, UK; Department of Engineering, University of Cambridge, UK.
| | - Umar Sadat
- Department of Surgery, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Martin J Graves
- University Departments of Radiology, University of Cambridge, UK
| | - Martin R Bennett
- Division of Cardiovascular Medicine, University of Cambridge, UK
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The influence of vascular anatomy on carotid artery stenting: A parametric study for damage assessment. J Biomech 2014; 47:890-8. [DOI: 10.1016/j.jbiomech.2014.01.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2014] [Indexed: 11/24/2022]
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40
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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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Gupta A, Baradaran H, Schweitzer AD, Kamel H, Pandya A, Delgado D, Dunning A, Mushlin AI, Sanelli PC. Carotid Plaque MRI and Stroke Risk. Stroke 2013; 44:3071-7. [PMID: 23988640 DOI: 10.1161/strokeaha.113.002551] [Citation(s) in RCA: 356] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose—
MRI characterization of carotid plaque has been studied recently as a potential tool to predict stroke caused by carotid atherosclerosis. We performed a systematic review and meta-analysis to summarize the association of MRI-determined intraplaque hemorrhage, lipid-rich necrotic core, and thinning/rupture of the fibrous cap with subsequent ischemic events.
Methods—
We performed a comprehensive literature search evaluating the association of carotid plaque composition on MRI with ischemic outcomes. We included cohort studies examining intraplaque hemorrhage, lipid-rich necrotic core, or thinning/rupture of the fibrous cap with mean follow-up of ≥1 month and an outcome measure of ipsilateral stroke or transient ischemic attack. A meta-analysis using a random-effects model with assessment of study heterogeneity and publication bias was performed.
Results—
Of the 3436 articles screened, 9 studies with a total of 779 subjects met eligibility for systematic review. The hazard ratios for intraplaque hemorrhage, lipid-rich necrotic core, and thinning/rupture of the fibrous cap as predictors of subsequent stroke/transient ischemic attack were 4.59 (95% confidence interval, 2.91–7.24), 3.00 (95% confidence interval, 1.51–5.95), and 5.93 (95% confidence interval, 2.65–13.20), respectively. No statistically significant heterogeneity or publication bias was present in the 3 main meta-analyses performed.
Conclusions—
The presence of intraplaque hemorrhage, lipid-rich necrotic core, and thinning/rupture of the fibrous cap on MRI of carotid plaque is associated with increased risk of future stroke or transient ischemic attack in patients with carotid atherosclerotic disease. Dedicated MRI of plaque composition offers stroke risk information beyond measurement of luminal stenosis in carotid atherosclerotic disease.
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Affiliation(s)
- Ajay Gupta
- From the Departments of Radiology (A.G., H.B., A.D.S., P.C.S.), Neurology (H.K.), and Public Health (A.P., A.D., A.I.M., P.C.S.) and Samuel J. Wood Library & C.V. Starr Biomedical Information Center (D.D.), Weill Cornell Medical College, New York, NY
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Saam T, Hetterich H, Hoffmann V, Yuan C, Dichgans M, Poppert H, Koeppel T, Hoffmann U, Reiser MF, Bamberg F. Meta-analysis and systematic review of the predictive value of carotid plaque hemorrhage on cerebrovascular events by magnetic resonance imaging. J Am Coll Cardiol 2013; 62:1081-1091. [PMID: 23850912 DOI: 10.1016/j.jacc.2013.06.015] [Citation(s) in RCA: 222] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 05/20/2013] [Accepted: 06/11/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVES This study sought to conduct a systematic review and meta-analysis to determine precise estimates of the predictive value of carotid intraplaque hemorrhage (IPH) as determined by magnetic resonance imaging (MRI) for cerebrovascular events. BACKGROUND There is emerging evidence that MR-based carotid atherosclerotic plaque assessment identifies high-risk features associated with cerebrovascular events. However, available data are based on smaller samples with heterogeneous source populations despite a promising value for noninvasive risk stratification. METHODS We searched PubMed, EMBASE, and the Cochrane Library through September 2012 for studies that followed >35 individuals after baseline MRI. Independent observers abstracted information on populations, MR techniques, outcomes, and study quality. Risk estimates of the presence of IPH for cerebrovascular events were derived in random effects regression analysis, and causes of heterogeneity were determined in meta-regression analysis. RESULTS We identified 8 eligible studies including 689 participants who underwent carotid MRI. The prevalence of IPH at baseline was high (49.0%). Over a median follow-up of 19.6 months, a total of 108 cerebrovascular events occurred (15.7% event rate). The presence of IPH was associated with an ∼6-fold higher risk for events (hazard ratio [HR]: 5.69; 95% confidence interval [CI]: 2.98 to 10.87). The annualized event rate in subjects with detectable IPH was 17.71% compared with 2.43% in patients without IPH. Meta-regression analysis showed symptomatic subjects had higher risks as compared with asymptomatic subjects (HR: 11.71, 95% CI: 5.17 to 26.48 vs. HR: 3.50, 95% CI: 2.59 to 4.73, p = 0.0065), Also, differences were observed for sex and sample size (all p < 0.01), with moderate visual publication bias due to missing smaller sample-size studies (p = 0.18). CONCLUSIONS Presence of IPH on MRI strongly predicts cerebrovascular events. Homogenization of future studies is warranted to allow for sufficient assessment of level of evidence for intervention trials.
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Affiliation(s)
- Tobias Saam
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany.
| | - Holger Hetterich
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Verena Hoffmann
- Institute of Biomedical Epidemiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Chun Yuan
- Department of Radiology, University of Washington, Seattle, Washington
| | - Martin Dichgans
- Institute for Stroke and Dementia Research, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Holger Poppert
- Department of Neurology, Technische Universität München, Munich, Germany
| | - Thomas Koeppel
- Division of Vascular and Endovascular Surgery, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Ulrich Hoffmann
- Division of Vascular Medicine, Medical Clinic and Policlinic IV, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Maximilian F Reiser
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Fabian Bamberg
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
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Karimi A, Navidbakhsh M, Faghihi S, Shojaei A, Hassani K. A finite element investigation on plaque vulnerability in realistic healthy and atherosclerotic human coronary arteries. Proc Inst Mech Eng H 2013; 227:148-61. [PMID: 23513986 DOI: 10.1177/0954411912461239] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Atherosclerosis is the most common arterial disease. It has been shown that stresses that are induced during blood circulation can cause plaque rupture and, in turn, lead to thrombosis and stroke. In this study, finite element method is used to predict plaque vulnerability based on peak plaque stress using human samples. A total of 23 healthy and atherosclerotic human coronary arteries of 14 healthy and 9 atherosclerotic patients are excised within 5 h postmortem. The samples are mounted on an uniaxial tensile test machine, and the obtained mechanical properties are used in two-dimensional and three-dimensional finite element models. The results including the Neo-Hookean hyperelastic coefficients of the samples as well as peak plaque stresses are analyzed. The results indicate that the atherosclerotic human coronary arteries have significantly (p < 0.05) higher stiffness compared with the healthy ones. The hypocellular plaque also has the highest stress values and, as a result, is most likely (vulnerable) to rupture, while the calcified type has the lowest stress values and, consequently, is expected to remain stable. The results could be used in the plaque vulnerability anticipation and have clinical implications in interventions and surgeries, including balloon angioplasty, bypass, and stenting.
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Affiliation(s)
- Alireza Karimi
- Department of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
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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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Sun J, Song Y, Chen H, Kerwin WS, Hippe DS, Dong L, Chen M, Zhou C, Hatsukami TS, Yuan C. Adventitial perfusion and intraplaque hemorrhage: a dynamic contrast-enhanced MRI study in the carotid artery. Stroke 2013; 44:1031-6. [PMID: 23471271 DOI: 10.1161/strokeaha.111.000435] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Autopsy studies have suggested a relationship between intraplaque hemorrhage (IPH) and vasa vasorum, which arise primarily from the adventitia. Adventitial vasa vasorum can be characterized in the carotid arteries by estimating perfusion parameters via dynamic contrast-enhanced MRI. The purpose of this investigation was to use dynamic contrast-enhanced MRI to test in vivo in a clinical population whether adventitial perfusion, indicative of vasa vasorum microstructure, is associated with IPH. METHODS Symptomatic patients with carotid plaque ipsilateral to the ischemic event underwent bilateral carotid artery MRI examination, which included multicontrast sequences for detecting IPH and a dynamic contrast-enhanced MRI sequence for characterizing adventitial perfusion. Kinetic modeling of the dynamic contrast-enhanced MRI time series was performed to estimate adventitial vp (fractional plasma volume, reflecting local blood supply) and K(trans) (transfer constant, reflecting vessel surface area, and permeability). RESULTS From the 27 patients (22 men; 69 ± 10 years of age) recruited, adventitial perfusion parameters were obtained in 50 arteries. The presence of IPH was associated with a significantly higher value in adventitial K(trans) (0.142 ± 0.042 vs 0.112 ± 0.029 min(-1); P<0.001) but not in vp (0.163 ± 0.064 vs 0.149 ± 0.062; P=0.338). This relationship remained after adjusting for symptomatic status, degree of stenosis, and other confounding factors. CONCLUSIONS This study demonstrated an independent pathophysiological link between the adventitia and IPH and related it to the microstructure of adventitial vasa vasorum. Adventitial perfusion imaging may be useful in studying plaque pathogenesis, but further examination through prospective studies is needed.
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Affiliation(s)
- Jie Sun
- Department of Radiology, University of Washington, Seattle, WA 98109, USA
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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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Kerwin WS. Carotid artery disease and stroke: assessing risk with vessel wall MRI. ISRN CARDIOLOGY 2012; 2012:180710. [PMID: 23209940 PMCID: PMC3504380 DOI: 10.5402/2012/180710] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 10/03/2012] [Indexed: 11/23/2022]
Abstract
Although MRI is widely used to diagnose stenotic carotid arteries, it also detects characteristics of the atherosclerotic plaque itself, including its size, composition, and activity. These features are emerging as additional risk factors for stroke that can be feasibly acquired clinically. This paper summarizes the state of evidence for a clinical role for MRI of carotid atherosclerosis.
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Affiliation(s)
- William S Kerwin
- Department of Radiology, University of Washington, Seattle, WA 98109, USA ; VPDiagnostics Incorporation, Seattle, WA 98101, USA
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Magnetic Resonance Imaging of Carotid Atherosclerosis and the Risk of Stroke. CURRENT CARDIOVASCULAR IMAGING REPORTS 2012. [DOI: 10.1007/s12410-012-9178-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Sadat U, Howarth SPS, Usman A, Tang TY, Graves MJ, Gillard JH. Sequential imaging of asymptomatic carotid atheroma using ultrasmall superparamagnetic iron oxide-enhanced magnetic resonance imaging: a feasibility study. J Stroke Cerebrovasc Dis 2012; 22:e271-6. [PMID: 22841932 DOI: 10.1016/j.jstrokecerebrovasdis.2012.06.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2012] [Revised: 06/23/2012] [Accepted: 06/26/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Inflammation within atheromatous plaques is a known risk factor for plaque vulnerability. This can be detected in vivo on high-resolution magnetic resonance imaging (MRI) using ultrasmall superparamagnetic iron oxide (USPIO) contrast medium. The purpose of this study was to assess the feasibility of performing sequential USPIO studies over a 1-year period. METHODS Ten patients with moderate asymptomatic carotid stenosis underwent carotid MRI imaging both before and 36 hours after USPIO infusion at 0, 6, and 12 months. Images were manually segmented into quadrants, and the signal change per quadrant was calculated at these time points. A mixed repeated measures statistical model was used to determine signal change attributable to USPIO uptake over time. RESULTS All patients remained asymptomatic during the study. The mixed model revealed no statistical difference in USPIO uptake between the 3 time points. Intraclass correlation coefficients revealed a good agreement of quadrant signal pre-USPIO infusion between 0 and 6 months (0.70) and 0 and 12 months (0.70). Good agreement of quadrant signal after USPIO infusion was shown between 0 and 6 months (0.68) and moderate agreement was shown between 0 and 12 months (0.33). CONCLUSIONS USPIO-enhanced sequential MRI of atheromatous carotid plaques is clinically feasible. This may have important implications for future longitudinal studies involving pharmacologic intervention in large patient cohorts.
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Affiliation(s)
- Umar Sadat
- Department of Radiology, Cambridge University Hospitals National Health Service Foundation Trust, Cambridge, United Kingdom; Department of Surgery, Cambridge University Hospitals National Health Service Foundation Trust, Cambridge, United Kingdom.
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