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Banchhor SK, Londhe ND, Araki T, Saba L, Radeva P, Khanna NN, Suri JS. Calcium detection, its quantification, and grayscale morphology-based risk stratification using machine learning in multimodality big data coronary and carotid scans: A review. Comput Biol Med 2018; 101:184-198. [DOI: 10.1016/j.compbiomed.2018.08.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 08/14/2018] [Accepted: 08/14/2018] [Indexed: 01/04/2023]
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2
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Khosa F, Clough RE, Wang X, Madhuranthakam AJ, Greenman RL. The potential role of IDEAL MRI for identification of lipids and hemorrhage in carotid artery plaques. Magn Reson Imaging 2018; 49:25-31. [DOI: 10.1016/j.mri.2017.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Accepted: 12/03/2017] [Indexed: 02/06/2023]
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3
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Lee J, Kil J, Kim DW, Kang SD. Usefulness of Plaque Magnetic Resonance Imaging in Identifying High-Risk Carotid Plaques Irrespective of the Degree of Stenosis. J Cerebrovasc Endovasc Neurosurg 2017; 19:291-300. [PMID: 29387630 PMCID: PMC5788837 DOI: 10.7461/jcen.2017.19.4.291] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 12/20/2017] [Accepted: 12/31/2017] [Indexed: 11/23/2022] Open
Abstract
Objective Measurement of the degree of stenosis is not enough to decide on the treatment strategy for patients with carotid stenosis. Plaque morphology examination is needed for such a decision-making. Thus, we evaluated the usefulness of plaque magnetic resonance imaging (MRI) to decide on the modality of treatment for patients with carotid atherosclerotic plaques. Materials and Methods Fifteen patients presenting with carotid stenosis between 2014 and 2016 were included. They underwent angiography for measurement of the degree of stenosis. Carotid plaques were visualized using MRI. Results There were six (40%) stable and nine (60%) unstable plaques. Seven symptomatic patients (77.7%) had unstable lesions and two symptomatic patients (33.3%) had stable lesions (p = 0.096). There were six (40%) intraplaque hemorrhage (IPH) cases. There were six symptomatic patients (100%) in the IPH group and three symptomatic patients (33.3%) in the non-IPH group (p = 0.013). The mean stenosis degree was 58.9% in the IPH group and 70.4% in the non-IPH group (p = 0.094). Symptoms occurred irrespective of the degree of the stenosis in the IPH groups. In the IPH group, the recurrent ischemic cerebrovascular event rate was 33.3%. Particularly, the recurrent ischemic cerebrovascular event rate was 66.7% in the IPH group with mild stenosis treated with medications. Conclusion IPH in plaque MRI is significantly associated with ischemic symptoms and has a high risk for subsequent ischemic cerebrovascular events irrespective of the degree of stenosis. Plaque MRI is a useful tool in predicting symptomatic risks for carotid stenosis irrespective of the degree of such stenosis.
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Affiliation(s)
- Jinseong Lee
- Institute of Wonkwang Medical Science, Department of Neurosurgery, Wonkwang University School of Medicine, Iksan, Korea
| | - Jinsang Kil
- Institute of Wonkwang Medical Science, Department of Neurosurgery, Wonkwang University School of Medicine, Iksan, Korea
| | - Dae-Won Kim
- Institute of Wonkwang Medical Science, Department of Neurosurgery, Wonkwang University School of Medicine, Iksan, Korea
| | - Sung-Don Kang
- Institute of Wonkwang Medical Science, Department of Neurosurgery, Wonkwang University School of Medicine, Iksan, Korea
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4
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Shahid SS, Gaul RT, Kerskens C, Flamini V, Lally C. Quantifying the ultrastructure of carotid arteries using high-resolution micro-diffusion tensor imaging—comparison of intact versus open cut tissue. ACTA ACUST UNITED AC 2017; 62:8850-8868. [DOI: 10.1088/1361-6560/aa9159] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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5
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McNally JS, Kim SE, Mendes J, Hadley JR, Sakata A, De Havenon AH, Treiman GS, Parker DL. Magnetic Resonance Imaging Detection of Intraplaque Hemorrhage. MAGNETIC RESONANCE INSIGHTS 2017; 10:1-8. [PMID: 28469441 PMCID: PMC5348123 DOI: 10.1177/1178623x17694150] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 01/25/2017] [Indexed: 11/16/2022]
Abstract
Carotid artery atherosclerosis is a major cause of ischemic stroke. For more than 30 years, future stroke risk and carotid stroke etiology have been determined using percent diameter stenosis based on clinical trials in the 1990s. In the past 10 years, magnetic resonance imaging (MRI) sequences have been developed to detect carotid intraplaque hemorrhage. By detecting carotid intraplaque hemorrhage, MRI identifies potential stroke sources that are often overlooked by lumen imaging. In addition, MRI can dramatically improve assessment of future stroke risk beyond lumen stenosis alone. In this review, we discuss the use of heavily T1-weighted MRI sequences used to detect carotid intraplaque hemorrhage. In addition, advances in ciné imaging, motion robust techniques, and specialized neck coils will be reviewed. Finally, the clinical use and future impact of MRI plaque hemorrhage imaging will be discussed.
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Affiliation(s)
- J Scott McNally
- Utah Center for Advanced Imaging Research, Department of Radiology and Imaging Sciences, The University of Utah, Salt Lake City, UT, USA
| | - Seong-Eun Kim
- Utah Center for Advanced Imaging Research, Department of Radiology and Imaging Sciences, The University of Utah, Salt Lake City, UT, USA
| | - Jason Mendes
- Utah Center for Advanced Imaging Research, Department of Radiology and Imaging Sciences, The University of Utah, Salt Lake City, UT, USA
| | - J Rock Hadley
- Utah Center for Advanced Imaging Research, Department of Radiology and Imaging Sciences, The University of Utah, Salt Lake City, UT, USA
| | - Akihiko Sakata
- Utah Center for Advanced Imaging Research, Department of Radiology and Imaging Sciences, The University of Utah, Salt Lake City, UT, USA
| | - Adam H De Havenon
- Department of Neurology, The University of Utah, Salt Lake City, UT, USA
| | - Gerald S Treiman
- Utah Center for Advanced Imaging Research, Department of Radiology and Imaging Sciences, The University of Utah, Salt Lake City, UT, USA
| | - Dennis L Parker
- Utah Center for Advanced Imaging Research, Department of Radiology and Imaging Sciences, The University of Utah, Salt Lake City, UT, USA
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van Hoof RHM, Heeneman S, Wildberger JE, Kooi ME. Dynamic Contrast-Enhanced MRI to Study Atherosclerotic Plaque Microvasculature. Curr Atheroscler Rep 2016; 18:33. [PMID: 27115144 PMCID: PMC4846686 DOI: 10.1007/s11883-016-0583-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Rupture of a vulnerable atherosclerotic plaque of the carotid artery is an important underlying cause of clinical ischemic events, such as stroke. Abundant microvasculature has been identified as an important aspect contributing to plaque vulnerability. Plaque microvasculature can be studied non-invasively with dynamic contrast-enhanced (DCE-)MRI in animals and patients. In recent years, several DCE-MRI studies have been published evaluating the association between microvasculature and other key features of plaque vulnerability (e.g., inflammation and intraplaque hemorrhage), as well as the effects of novel therapeutic interventions. The present paper reviews this literature, focusing on DCE-MRI methods of acquisition and analysis of atherosclerotic plaques, the current state and future potential of DCE-MRI in the evaluation of plaque microvasculature in clinical and preclinical settings.
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Affiliation(s)
- Raf H. M. van Hoof
- />Department of Radiology, Maastricht University Medical Center (MUMC), P.O. Box 5800, 6202 AZ Maastricht, The Netherlands
- />CARIM School for Cardiovascular Diseases, Maastricht University, P.O. Box 616, Maastricht, 6200 MD The Netherlands
| | - Sylvia Heeneman
- />CARIM School for Cardiovascular Diseases, Maastricht University, P.O. Box 616, Maastricht, 6200 MD The Netherlands
- />Department of Pathology, Maastricht University Medical Center (MUMC), P.O. Box 5800, Maastricht, 6202 AZ The Netherlands
| | - Joachim E. Wildberger
- />Department of Radiology, Maastricht University Medical Center (MUMC), P.O. Box 5800, 6202 AZ Maastricht, The Netherlands
- />CARIM School for Cardiovascular Diseases, Maastricht University, P.O. Box 616, Maastricht, 6200 MD The Netherlands
| | - M. Eline Kooi
- />Department of Radiology, Maastricht University Medical Center (MUMC), P.O. Box 5800, 6202 AZ Maastricht, The Netherlands
- />CARIM School for Cardiovascular Diseases, Maastricht University, P.O. Box 616, Maastricht, 6200 MD The Netherlands
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7
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Pelisek J, Wendorff H, Wendorff C, Kuehnl A, Eckstein HH. Age-associated changes in human carotid atherosclerotic plaques. Ann Med 2016; 48:541-551. [PMID: 27595161 DOI: 10.1080/07853890.2016.1204468] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Little is known about changes in carotid plaque morphology during aging and the possible impact on cardiovascular events. Only few studies addressed so far age-related modifications within atherosclerotic lesions. Therefore, in this work we endeavored to summarize the current knowledge about changing of plaque composition in elderly. The data from hitherto existing studies confirm that atherosclerotic plaques undergo distinct alternations with advanced age. However, the results are often ambiguous and the changes do not seem to be as disastrous as expected. Interestingly, none of the studies could definitely evidence increased plaque vulnerability with advanced age. Nevertheless, based on the previous work showing decrease in elastin fibers, fibroatheroma, SMCs, overall cellularity and increase in the area of lipid core, hemorrhage, and calcification, the plaque morphology appears to transform toward unstable plaques. Otherwise, even if inflammatory cells often accumulate in plaques of younger patients, their amount is reduced in the older age and so far no clear association has been observed between thin fibrous cap and aging. Thus, the accurate contribution of age-related changes in plaque morphology to cardiovascular events has yet to be elucidated. KEY MESSAGES Composition of carotid atherosclerotic lesions changes during aging. These alternations are however, just moderate and depend upon additional variables, such as life style, accompanying disease, genetics, and other factors that have yet to be determined. Based on the current data, the age-associated plaque morphology seems to transform toward vulnerable plaques. However, the changes do not seem to be as disastrous as expected.
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Affiliation(s)
- Jaroslav Pelisek
- a Department of Vascular and Endovascular Surgery , Klinikum rechts der Isar der Technischen Universitaet Muenchen , Munich , Germany
| | - Heiko Wendorff
- a Department of Vascular and Endovascular Surgery , Klinikum rechts der Isar der Technischen Universitaet Muenchen , Munich , Germany
| | - Carina Wendorff
- a Department of Vascular and Endovascular Surgery , Klinikum rechts der Isar der Technischen Universitaet Muenchen , Munich , Germany
| | - Andreas Kuehnl
- a Department of Vascular and Endovascular Surgery , Klinikum rechts der Isar der Technischen Universitaet Muenchen , Munich , Germany
| | - Hans-Henning Eckstein
- a Department of Vascular and Endovascular Surgery , Klinikum rechts der Isar der Technischen Universitaet Muenchen , Munich , Germany
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8
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Increasing the Spatial Resolution of 3T Carotid MRI Has No Beneficial Effect for Plaque Component Measurement Reproducibility. PLoS One 2015; 10:e0130878. [PMID: 26161783 PMCID: PMC4498614 DOI: 10.1371/journal.pone.0130878] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 05/26/2015] [Indexed: 11/19/2022] Open
Abstract
Purpose Different in-plane resolutions have been used for carotid 3T MRI. We compared the reproducibility, as well as the within- and between reader variability of high and routinely used spatial resolution in scans of patients with atherosclerotic carotid artery disease. Since no consensus exists about the optimal segmentation method, we analysed all imaging data using two different segmentation methods. Materials and Methods In 31 patient with carotid atherosclerosis a high (0.25 × 0.25 mm2; HR) and routinely used (0.50 × 0.50 mm2; LR) spatial resolution carotid MRI scan were performed within one month. A fully blinded closed and a simultaneously open segmentation were used to quantify the lipid rich necrotic core (LRNC), calcified and loose matrix (LM) plaque area and the fibrous cap (FC) thickness. Results No significant differences were observed between scan-rescan reproducibility for HR versus LR measurements, nor did we find any significant difference between the within-reader and between-reader reproducibility. The same applies for differences between the open and closed reads. All intraclass correlation coefficients between scans and rescans for the LRNC, calcified and LM plaque area, as well as the FC thickness measurements with the open segmentation method were excellent (all above 0.75). Conclusions Increasing the spatial resolution at the expense of the contrast-to-noise ratio does not improve carotid plaque component scan-rescan reproducibility in patients with atherosclerotic carotid disease, nor does using a different segmentation method.
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Quantification of plaque lipids in the aortic root of ApoE-deficient mice by 3D DIXON magnetic resonance imaging in an ex vivo model. Eur Radiol 2014; 25:736-44. [DOI: 10.1007/s00330-014-3456-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Revised: 09/03/2014] [Accepted: 09/26/2014] [Indexed: 10/24/2022]
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10
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Scott McNally J, Yoon HC, Kim SE, Narra KK, McLaughlin MS, Parker DL, Treiman GS. Carotid MRI Detection of Intraplaque Hemorrhage at 3T and 1.5T. J Neuroimaging 2014; 25:390-6. [PMID: 25040677 DOI: 10.1111/jon.12146] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 03/27/2014] [Accepted: 03/30/2014] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Carotid intraplaque hemorrhage leads to plaque progression and ischemic events. Detection can be accomplished with 3T T1w sequences, but may be limited by false-positive lipid/necrosis. The purpose of this study was threefold: (1) to determine if magnetization-prepared rapid acquisition with gradient-echo (MPRAGE) detects intraplaque hemorrhage versus lipid/necrosis; (2) if 3T MPRAGE image quality is retained at 1.5T; and (3) to determine observer agreement. METHODS MPRAGE positive areas were compared to hemorrhage and lipid/necrosis areas from 100 carotid endarterectomy slides in 12 subjects using multivariable linear regression. Image quality was determined between 3T and 1.5T in 716 carotid arteries using t-tests and multivariable linear regression. Kappa analysis was used to determine agreement. RESULTS Intraplaque hemorrhage, not lipid/necrosis, was a significant predictor of MPRAGE positive area before and after adjusting for confounders (slope = .52 vs. .51, P < .001). Image quality at 3T was slightly lower than 1.5T (mean 3.87 vs. 4.34, P < .0001). 3T image quality remained slightly decreased before and after adjusting for confounders (slope = -.46 vs. -.41, P < .001). Kappa values for inter-/intraobserver agreement were .807/.919 at 3T and .803/.871 at 1.5T. CONCLUSIONS Carotid MPRAGE detects intraplaque hemorrhage, not lipid/necrosis. 3T image quality was retained at 1.5T with very good observer agreement.
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Affiliation(s)
- J Scott McNally
- Utah Center for Advanced Imaging Research, Department of Radiology, University of Utah School of Medicine, Salt Lake City, UT
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11
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Gomes EPSG, Rochitte CE, Azevedo CF, Lemos PA, Gutierrez PS, César LAM. Ex-vivo Assessment of Coronary Artery Atherosclerosis by Magnetic Resonance Imaging: Correlation with Histopathology. Open Cardiovasc Med J 2014; 8:26-34. [PMID: 24847387 PMCID: PMC4021207 DOI: 10.2174/1874192401408010026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 01/31/2014] [Accepted: 02/04/2014] [Indexed: 11/22/2022] Open
Abstract
Introduction:
In recent
years, high-resolution magnetic resonance imaging (MRI) has emerged as a very
promising technique for studying atherosclerotic disease in humans. Aim:
In the present study we sought to determine whether MRI allowed for the
morphological characterization of the coronary vessel wall and atherosclerotic
plaques using histopathological assessment as the reference standard.
Methods: The study population consisted of 13 patients who died
of acute myocardial infarction and underwent autopsy. The proximal portions of
the coronary arteries were excised and were evaluated both by MRI and by
histopathology. For each arterial segment, the following parameters were
calculated through manual planimetry: 1. total vessel area (TVA); 2. luminal
area (LA) and 3. plaque area (PA). Results: A total of 207
coronary artery cross-sections were found to be suitable for analysis by both
MRI and histopathology and were included in the final analyses. Both methods
demonstrated moderate to good agreement for the quantification of TVA (mean
difference = 2.4±2.4 mm2, 95‰ limits of agreement from -2.4 to +7.2
mm2; CCC = 0.69, 95‰ CI from 0.63 to 0.75), LA (mean difference =
0.0±1.7 mm2, 95‰ limits of agreement from -3.3 to + 3.3 mm2;
CCC = 0.84, 95‰ CI from 0.80 to 0.88) and PA (mean difference = 2.4±2.4 mm2,
95‰ limits of agreement from -2.3 to + 7.1 mm2; CCC = 0.64, 95‰ CI
from 0.58 to 0.71).
Conclusion:
In this
ex vivo experimental model we demonstrated good agreement between coronary
artery morphometrical measurements obtained by high-resolution MRI and by
histopathology.
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Affiliation(s)
| | | | - Clerio F Azevedo
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil
| | - Pedro A Lemos
- Heart Institute (InCor) University of São Paulo Medical School, São Paulo, Brazil
| | | | - Luiz Antonio M César
- Heart Institute (InCor) University of São Paulo Medical School, São Paulo, Brazil
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Edema and fibrosis imaging by cardiovascular magnetic resonance: how can the experience of Cardiology be best utilized in rheumatological practice? Semin Arthritis Rheum 2014; 44:76-85. [PMID: 24582213 DOI: 10.1016/j.semarthrit.2014.01.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 10/19/2013] [Accepted: 01/17/2014] [Indexed: 12/19/2022]
Abstract
OBJECTIVES CMR, a non-invasive, non-radiating technique can detect myocardial oedema and fibrosis. METHOD CMR imaging, using T2-weighted and T1-weighted gadolinium enhanced images, has been successfully used in Cardiology to detect myocarditis, myocardial infarction and various cardiomyopathies. RESULTS Transmitting this experience from Cardiology into Rheumatology may be of important value because: (a) heart involvement with atypical clinical presentation is common in autoimmune connective tissue diseases (CTDs). (b) CMR can reliably and reproducibly detect early myocardial tissue changes. (c) CMR can identify disease acuity and detect various patterns of heart involvement in CTDs, including myocarditis, myocardial infarction and diffuse vasculitis. (d) CMR can assess heart lesion severity and aid therapeutic decisions in CTDs. CONCLUSION The CMR experience, transferred from Cardiology into Rheumatology, may facilitate early and accurate diagnosis of heart involvement in these diseases and potentially targeted heart treatment.
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13
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Biasiolli L, Lindsay AC, Chai JT, Choudhury RP, Robson MD. In-vivo quantitative T2 mapping of carotid arteries in atherosclerotic patients: segmentation and T2 measurement of plaque components. J Cardiovasc Magn Reson 2013; 15:69. [PMID: 23953780 PMCID: PMC3751854 DOI: 10.1186/1532-429x-15-69] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 08/08/2013] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Atherosclerotic plaques in carotid arteries can be characterized in-vivo by multicontrast cardiovascular magnetic resonance (CMR), which has been thoroughly validated with histology. However, the non-quantitative nature of multicontrast CMR and the need for extensive post-acquisition interpretation limit the widespread clinical application of in-vivo CMR plaque characterization. Quantitative T2 mapping is a promising alternative since it can provide absolute physical measurements of plaque components that can be standardized among different CMR systems and widely adopted in multi-centre studies. The purpose of this study was to investigate the use of in-vivo T2 mapping for atherosclerotic plaque characterization by performing American Heart Association (AHA) plaque type classification, segmenting carotid T2 maps and measuring in-vivo T2 values of plaque components. METHODS The carotid arteries of 15 atherosclerotic patients (11 males, 71 ± 10 years) were imaged at 3 T using the conventional multicontrast protocol and Multiple-Spin-Echo (Multi-SE). T2 maps of carotid arteries were generated by mono-exponential fitting to the series of images acquired by Multi-SE using nonlinear least-squares regression. Two reviewers independently classified carotid plaque types following the CMR-modified AHA scheme, one using multicontrast CMR and the other using T2 maps and time-of-flight (TOF) angiography. A semi-automated method based on Bayes classifiers segmented the T2 maps of carotid arteries into 4 classes: calcification, lipid-rich necrotic core (LRNC), fibrous tissue and recent IPH. Mean ± SD of the T2 values of voxels classified as LRNC, fibrous tissue and recent IPH were calculated. RESULTS In 37 images of carotid arteries from 15 patients, AHA plaque type classified by multicontrast CMR and by T2 maps (+ TOF) showed good agreement (76% of matching classifications and Cohen's κ = 0.68). The T2 maps of 14 normal arteries were used to measure T2 of tunica intima and media (T2 = 54 ± 13 ms). From 11865 voxels in the T2 maps of 15 arteries with advanced atherosclerosis, 2394 voxels were classified by the segmentation algorithm as LRNC (T2 = 37 ± 5 ms) and 7511 voxels as fibrous tissue (T2 = 56 ± 9 ms); 192 voxels were identified as calcification and one recent IPH (236 voxels, T2 = 107 ± 25 ms) was detected on T2 maps and confirmed by multicontrast CMR. CONCLUSIONS This carotid CMR study shows the potential of in-vivo T2 mapping for atherosclerotic plaque characterization. Agreement between AHA plaque types classified by T2 maps (+TOF) and by conventional multicontrast CMR was good, and T2 measured in-vivo in LRNC, fibrous tissue and recent IPH demonstrated the ability to discriminate plaque components on T2 maps.
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Affiliation(s)
- Luca Biasiolli
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
- Oxford Acute Vascular Imaging Centre (AVIC), Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Alistair C Lindsay
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Joshua T Chai
- Oxford Acute Vascular Imaging Centre (AVIC), Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Robin P Choudhury
- Oxford Acute Vascular Imaging Centre (AVIC), Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Matthew D Robson
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
- Oxford Acute Vascular Imaging Centre (AVIC), Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
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14
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Degnan AJ, Young VE, Tang TY, Gill AB, Graves MJ, Gillard JH, Patterson AJ. Ex vivo study of carotid endarterectomy specimens: quantitative relaxation times within atherosclerotic plaque tissues. Magn Reson Imaging 2012; 30:1017-21. [PMID: 22503089 DOI: 10.1016/j.mri.2012.02.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 01/10/2012] [Accepted: 02/17/2012] [Indexed: 10/28/2022]
Abstract
PURPOSE Previous studies reporting relaxation times within atherosclerotic plaque have typically used dedicated small-bore high-field systems and small sample sizes. This study reports quantitative T(1), T(2) and T(2) relaxation times within plaque tissue at 1.5 T using spatially co-matched histology to determine tissue constituents. METHODS Ten carotid endarterectomy specimens were removed from patients with advanced atherosclerosis. Imaging was performed on a 1.5-T whole-body scanner using a custom built 10-mm diameter receive-only solenoid coil. A protocol was defined to allow subsequent computation of T(1), T(2) and T(2) relaxation times using multi-flip angle spoiled gradient echo, multi-echo fast spin echo and multi-echo gradient echo sequences, respectively. The specimens were subsequently processed for histology and individually sectioned into 2-mm blocks to allow subsequent co-registration. Each imaging sequence was imported into in-house software and displayed alongside the digitized histology sections. Regions of interest were defined to demarcate fibrous cap, connective tissue and lipid/necrotic core at matched slice-locations. Relaxation times were calculated using Levenberg-Marquardt's least squares curve fitting algorithm. A linear-mixed effect model was applied to account for multiple measurements from the same patient and establish if there was a statistically significant difference between the plaque tissue constituents. RESULTS T(2) and T(2) relaxation times were statistically different between all plaque tissues (P=.026 and P=.002 respectively) [T(2): lipid/necrotic core was lower 47 ± 13.7 ms than connective tissue (67 ± 22.5 ms) and fibrous cap (60 ± 13.2 ms); T(2): fibrous cap was higher (48 ± 15.5 ms) than connective tissue (19 ± 10.6 ms) and lipid/necrotic core (24 ± 8.2 ms)]. T(1) relaxation times were not significantly different (P=.287) [T(1): Fibrous cap: 933 ± 271.9 ms; connective tissue (1002 ± 272.9 ms) and lipid/necrotic core (1044 ± 304.0 ms)]. We were unable to demarcate hemorrhage and calcium following histology processing. CONCLUSIONS This study demonstrates that there is a significant difference between qT(2) and qT(2) in plaque tissues types. Derivation of quantitative relaxation times shows promise for determining plaque tissue constituents.
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Affiliation(s)
- Andrew J Degnan
- Department of Radiology, Cambridge University Hospital NHS Foundation Trust, Cambridge, CB2 0QQ
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15
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van 't Klooster R, Naggara O, Marsico R, Reiber JHC, Meder JF, van der Geest RJ, Touzé E, Oppenheim C. Automated versus manual in vivo segmentation of carotid plaque MRI. AJNR Am J Neuroradiol 2012; 33:1621-7. [PMID: 22442043 DOI: 10.3174/ajnr.a3028] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Automatically identifying carotid plaque composition using MR imaging remains a challenging task in vivo. The purpose of our study was to compare the detection and quantification of carotid artery atherosclerotic plaque components based on in vivo MR imaging data using manual and automated segmentation. MATERIALS AND METHODS Sixty patients from a multicenter study were split into a training group (20 patients) and a study group (40 patients). Each MR imaging study consisted of 4 high-resolution carotid wall sequences (T1, T2, PDw, TOF). Manual segmentation was performed by delineation of the vessel wall and different plaque components. Automated segmentation was performed in the study group by a supervised classifier trained on images from the training group of patients. RESULTS For the detection of plaque components, the agreement between the visual and automated analysis was moderate for calcifications (κ = 0.59, CI 95% [0.36-0.82]) and good for hemorrhage (0.65 [0.42-0.88]) and lipids (0.65 [0.03-1.27]). For quantification of plaque volumes, the intraclass correlation was high for hemorrhage (0.80 [0.54-0.92]) and fibrous tissue (0.80 [0.65-0.89]), good for lipids (0.65 [0.43-0.80]), and poor for calcifications. CONCLUSIONS In 40 patients with carotid stenosis, our results indicated that it was possible to automatically detect carotid plaque components with substantial or good agreement with visual identification, and that the volumes obtained manually and automatically were reasonably consistent for hemorrhage and lipids but not for calcium.
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Affiliation(s)
- R van 't Klooster
- Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
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te Boekhorst BC, van 't Klooster R, Bovens SM, van de Kolk KW, Cramer MJ, van Oosterhout MF, Doevendans PA, van der Geest RJ, Pasterkamp G, van Echteld CJ. Evaluation of multicontrast MRI including fat suppression and inversion recovery spin echo for identification of intra-plaque hemorrhage and lipid core in human carotid plaque using the mahalanobis distance measure. Magn Reson Med 2011; 67:1764-75. [PMID: 21997890 DOI: 10.1002/mrm.23191] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 07/27/2011] [Accepted: 07/30/2011] [Indexed: 11/09/2022]
Abstract
Intra-plaque hemorrhage (IPH) and lipid core, characteristics of rupture prone carotid plaques, are often visualized in vivo with MRI using T1 weighted gradient and spin echo, respectively. Increasing magnetic field strength may help to identify IPH and lipid core better. As a proof of concept, automatic segmentation of plaque components was performed with the Mahalanobis distance (MD) measure derived from image contrast from multicontrast MR images including inversion recovery spin echo and T1 weighted gradient echo with fat suppression. After MRI of nine formaldehyde-fixated autopsy specimens, the MDs and Euclidean Distances between plaque component intensities were calculated for each MR weighting. The distances from the carotid bifurcation and the size and shape of calcification spots were used as landmarks for coregistration of MRI and histology. MD between collagen/cell-rich area and IPH was largest with inversion recovery spin echo (4.2/9.3, respectively), between collagen/cell-rich area/foam cells and lipid core with T1 weighted gradient echo with fat suppression (26.9/38.2/4.6, respectively). The accuracy of detection of IPH, cell-rich area, and collagen increased when the MD classifier was used compared with the Euclidean Distance classifier. The enhanced conspicuity of lipid core and IPH in human carotid artery plaque, using ex vivo T1 weighted gradient echo with fat suppression and inversion recovery spin echo MRI and MD classifiers, demands further in vivo evaluation in patients.
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Kim SE, Treiman GS, Roberts JA, Jeong EK, Shi X, Hadley JR, Parker DL. In vivo and ex vivo measurements of the mean ADC values of lipid necrotic core and hemorrhage obtained from diffusion weighted imaging in human atherosclerotic plaques. J Magn Reson Imaging 2011; 34:1167-75. [DOI: 10.1002/jmri.22736] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Accepted: 07/15/2011] [Indexed: 11/10/2022] Open
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Noguchi T, Yamada N, Higashi M, Goto Y, Naito H. High-Intensity Signals in Carotid Plaques on T1-Weighted Magnetic Resonance Imaging Predict Coronary Events in Patients With Coronary Artery Disease. J Am Coll Cardiol 2011; 58:416-22. [PMID: 21757120 DOI: 10.1016/j.jacc.2011.01.056] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2010] [Revised: 01/06/2011] [Accepted: 01/31/2011] [Indexed: 01/01/2023]
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Qiao Y, Steinman DA, Qin Q, Etesami M, Schär M, Astor BC, Wasserman BA. Intracranial arterial wall imaging using three-dimensional high isotropic resolution black blood MRI at 3.0 Tesla. J Magn Reson Imaging 2011; 34:22-30. [DOI: 10.1002/jmri.22592] [Citation(s) in RCA: 201] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Abstract
Atherosclerosis and its thrombotic complications are the major cause of morbidity and mortality in the industrialized countries. Despite advances in our understanding of the pathophysiology, pathogenesis, and new treatment modalities, the absence of an adequate non-invasive imaging tool for early detection limits both the prevention and treatment of patients with various degrees and anatomical localizations of atherothrombotic disease. An ideal clinical imaging modality for atherosclerotic vascular disease should be safe, inexpensive, non-invasive or minimally invasive, accurate, and reproducible, and the results should correlate with the extent of atherosclerotic disease and have high predictive values for future clinical events. High-resolution magnetic resonance imaging (MRI) has emerged as the most promising technique for studying atherothrombotic disease in humans in vivo. Most importantly, MRI allows for the characterization of plaque composition, i.e. the discrimination of lipid core, fibrosis, calcification, and intraplaque haemorrhage deposits. Magnetic resonance imaging also allows for the detection of arterial thrombi and in defining thrombus age. Magnetic resonance imaging has been used to monitor plaque progression and regression in several animal models of atherosclerosis and in humans. Emerging MRI techniques capable of imaging biological processes, including inflammation, neovascularization, and mechanical forces, may aid in advancing our understanding of the atherothrombotic disease. Advances in diagnosis do prosper provided they march hand-in-hand with advances in treatment. We stand at the threshold of accurate non-invasive assessment of atherosclerosis. Thus, MRI opens new strategies ranging from screening of high-risk patients for early detection and treatment as well as monitoring of the target lesions for pharmacological intervention. Identification of subclinical atherosclerosis and early treatment initiation has the potential to surpass conventional risk factor assessment and management in terms of overall impact on cardiovascular morbidity and mortality. Such strategy is currently under clinical investigation.
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Affiliation(s)
- Roberto Corti
- Cardiology, Cardiovascular Center, University Hospital Zurich, Rämistrasse 100, CH-8091 Zurich, Switzerland.
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Underhill HR, Yuan C. Carotid MRI: a tool for monitoring individual response to cardiovascular therapy? Expert Rev Cardiovasc Ther 2011; 9:63-80. [PMID: 21166529 DOI: 10.1586/erc.10.172] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Stroke remains a leading cause of morbidity and mortality. While stroke-related mortality has declined over the past four decades, data indicate that the mortality rate has begun to plateau. This change in trend may be attributable to variation in individual response to therapies that were derived from population-based studies. Further reductions in stroke mortality may require individualized care governed by directly monitoring the effects of cardiovascular therapy. In this article, carotid MRI is considered as a tool for monitoring in vivo carotid atherosclerotic disease, a principal etiology of stroke. Carotid MRI has been previously utilized to identify specific plaque features beyond luminal stenosis that are predictive of transient ischemic attack and stroke. To gain perspective on the possibility of monitoring plaque change within the individual, clinical trials and natural history studies that have used serial carotid MRI are considered. Data from these studies indicate that patients with a lipid-rich necrotic core with or without intraplaque hemorrhage may represent the desired phenotype for monitoring treatment effects in the individual. Advances in tissue-specific sequences, acquisition resolution, scan time, and techniques for monitoring inflammation and mechanical forces are expected to enable earlier detection of response to therapy. In so doing, cost-effective multicenter studies can be conducted to confirm the anticipated positive effects on outcomes of using carotid MRI for individualized care in patients with carotid atherosclerosis. In accordance, carotid MRI is poised to emerge as a powerful clinical tool for individualized management of carotid atherosclerotic disease to prevent stroke.
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Affiliation(s)
- Hunter R Underhill
- Department of Medicine, Division of Medical Genetics, University of Washington, 1705 NE Pacific Street, K253, Box 357720, Seattle, WA 98195, USA.
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22
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Morishige K, Kacher DF, Libby P, Josephson L, Ganz P, Weissleder R, Aikawa M. High-resolution magnetic resonance imaging enhanced with superparamagnetic nanoparticles measures macrophage burden in atherosclerosis. Circulation 2010; 122:1707-15. [PMID: 20937980 DOI: 10.1161/circulationaha.109.891804] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Macrophages contribute to the progression and acute complications of atherosclerosis. Macrophage imaging may serve as a biomarker to identify subclinical inflamed lesions, to predict future risk, and to aid in the assessment of novel therapies. METHODS AND RESULTS To test the hypothesis that nanoparticle-enhanced, high-resolution magnetic resonance imaging (MRI) can measure plaque macrophage accumulation, we used 3-T MRI with a macrophage-targeted superparamagnetic nanoparticle preparation (monocrystalline iron oxide nanoparticles-47 [MION-47]) in cholesterol-fed New Zealand White rabbits 6 months after balloon injury. In vivo MRI visualized thickened abdominal aortas on both T1- and T2-weighted spin-echo images (T1 spin echo, 20 axial slices per animal; T2 spin echo, 28 slices per animal). Seventy-two hours after MION-47 injection, aortas exhibited lower T2 signal intensity compared with before contrast imaging (signal intensity ratio, aortic wall/muscle: before, 1.44 ± 0.26 versus after, 0.95 ± 0.22; 164 slices; P<0.01), whereas T1 spin echo images showed no significant change. MRI on ex vivo specimens provided similar results. Histological studies colocalized iron accumulation with immunoreactive macrophages in atheromata. The magnitude of signal intensity reduction on T2 spin echo in vivo images further correlated with macrophage areas in situ (150 slices; r=0.73). Treatment with rosuvastatin for 3 months yielded diminished macrophage content (P<0.05) and reversed T2 signal intensity changes (P<0.005). Signal changes in rosuvastatin-treated rabbits correlated with reduced macrophage burden (r=0.73). In vitro validation studies showed concentration-dependent MION-47 uptake by human primary macrophages. CONCLUSION The magnitude of T2 signal intensity reduction in high-resolution MRI after administration of superparamagnetic phagocytosable nanoparticles can assess macrophage burden in atheromata, providing a clinically translatable tool to identify inflamed plaques and to monitor therapy-mediated changes in plaque inflammation.
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Affiliation(s)
- Kunio Morishige
- Donald W. Reynolds Cardiovascular Clinical Research Center at Harvard Medical School, Boston, MA, USA
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Xie J, Bi X, Fan Z, Bhat H, Shah S, Zuehlsdorff S, Li D. 3D flow-independent peripheral vessel wall imaging using T(2)-prepared phase-sensitive inversion-recovery steady-state free precession. J Magn Reson Imaging 2010; 32:399-408. [PMID: 20677269 PMCID: PMC2915467 DOI: 10.1002/jmri.22272] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
PURPOSE To develop a 3D flow-independent peripheral vessel wall imaging method using T(2)-prepared phase-sensitive inversion-recovery (T(2)PSIR) steady-state free precession (SSFP). MATERIALS AND METHODS A 3D T(2)-prepared and nonselective inversion-recovery SSFP sequence was designed to achieve flow-independent blood suppression for vessel wall imaging based on T(1) and T(2) properties of the vessel wall and blood. To maximize image contrast and reduce its dependence on the inversion time (TI), phase-sensitive reconstruction was used to restore the true signal difference between vessel wall and blood. The feasibility of this technique for peripheral artery wall imaging was tested in 13 healthy subjects. Image signal-to-noise ratio (SNR), wall/lumen contrast-to-noise ratio (CNR), and scan efficiency were compared between this technique and conventional 2D double inversion recovery - turbo spin echo (DIR-TSE) in eight subjects. RESULTS 3D T(2)PSIR SSFP provided more efficient data acquisition (32 slices and 64 mm in 4 minutes, 7.5 seconds per slice) than 2D DIR-TSE (2-3 minutes per slice). SNR of the vessel wall and CNR between vessel wall and lumen were significantly increased as compared to those of DIR-TSE (P < 0.001). Vessel wall and lumen areas of the two techniques are strongly correlated (intraclass correlation coefficients: 0.975 and 0.937, respectively; P < 0.001 for both). The lumen area of T(2)PSIR SSFP is slightly larger than that of DIR-TSE (P = 0.008). The difference in vessel wall area between the two techniques is not statistically significant. CONCLUSION T(2)PSIR SSFP is a promising technique for peripheral vessel wall imaging. It provides excellent blood signal suppression and vessel wall/lumen contrast. It can cover a 3D volume efficiently and is flow- and TI-independent.
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Affiliation(s)
- Jingsi Xie
- Department of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL
| | - Xiaoming Bi
- Department of Siemens Healthcare, Chicago, IL, USA
| | - Zhaoyang Fan
- Department of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL
| | - Himanshu Bhat
- Department of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL
| | - Saurabh Shah
- Department of Siemens Healthcare, Chicago, IL, USA
| | | | - Debiao Li
- Department of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL
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Brown R, Nguyen TD, Spincemaille P, Cham MD, Choi G, Winchester PA, Prince MR, Wang Y. Effect of blood flow on double inversion recovery vessel wall MRI of the peripheral arteries: quantitation with T2 mapping and comparison with flow-insensitive T2-prepared inversion recovery imaging. Magn Reson Med 2010; 63:736-44. [PMID: 20187182 DOI: 10.1002/mrm.22227] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Blood suppression in the lower extremities using flow-reliant methods such as double inversion recovery may be problematic due to slow blood flow. T(2) mapping using fast spin echo (FSE) acquisition was utilized to quantitate the effectiveness of double inversion recovery blood suppression in 13 subjects and showed that 25 +/- 12% of perceived vessel wall pixels in the popliteal arteries contained artifactual blood signal. To overcome this problem, a flow-insensitive T(2)-prepared inversion recovery sequence was implemented and optimal timing parameters were calculated for FSE acquisition. Black blood vessel wall imaging of the popliteal and femoral arteries was performed using two-dimensional T(2)-prepared inversion recovery-FSE in the same 13 subjects. Comparison with two-dimensional double inversion recovery-FSE showed that T(2)-prepared inversion recovery-FSE reduced wall-mimicking blood artifacts that inflated double inversion recovery-FSE vessel wall area measurements in the popliteal artery.
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Affiliation(s)
- Ryan Brown
- Department of Radiology, Weill Medical College of Cornell University, New York, New York 10016, USA.
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25
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Bitar R, Moody AR, Symons S, Leung G, Crisp S, Kiss A, Nelson A, Maggisano R. Carotid atherosclerotic calcification does not result in high signal intensity in MR imaging of intraplaque hemorrhage. AJNR Am J Neuroradiol 2010; 31:1403-7. [PMID: 20466799 DOI: 10.3174/ajnr.a2126] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Calcium can potentially shorten T1, generating high signal intensity in GREs. Because IPH appears as high signal intensity in MRIPH and the surface effects of calcium can potentially shorten T1 of surrounding water protons, the purpose of this study was to evaluate whether the high signal intensity seen on MRIPH could be attributed solely to IPH and not calcification. MATERIALS AND METHODS Eleven patients undergoing carotid endarterectomy were imaged by using MRIPH. Calcification was assessed by scanning respective endarterectomy specimens with a tabletop MicroCT. MRIPH/MicroCT correlation used an 8-segment template. Two readers evaluated images from both modalities. Agreement between MRIPH/MicroCT was measured by calculating Cohen κ. RESULTS High signal intensity was seen in 58.8% and 68.9% (readers 1 and 2, respectively) of MRIPH segments, whereas calcification was seen in 44.7% and 32.1% (readers 1 and 2, respectively) of MicroCT segments. High signal intensity seen by MRIPH showed very good but inverse agreement to calcification (κ = -0.90; P < .0001, 95% CI, -0.93 to -0.86, reader 1; and κ = -0.74; P < .0001; 95% CI, -0.81 to -0.69, reader 2). Most interesting, high signal intensity demonstrated excellent agreement with lack of calcification on MicroCT (κ = 0.92; P < .0001; 95% CI, 0.89-0.94, reader 1; and κ = 0.97; P < .0001; 95% CI, 0.96-0.99, reader 2). In a very small number of segments, high signal intensity was seen in MRIPH, and calcification was seen on MicroCT; however, these represented a very small proportion of segments with high signal intensity (5.9% and 1.6%, readers 1 and 2, respectively). CONCLUSIONS High signal intensity, therefore, reliably identified IPH, known to describe complicated plaque, rather than calcification, which is increasingly recognized as identifying more stable vascular disease.
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Affiliation(s)
- R Bitar
- Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada
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26
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Chan CF, Keenan NG, Nielles-Vallespin S, Gatehouse P, Sheppard MN, Boyle JJ, Pennell DJ, Firmin DN. Ultra-short echo time cardiovascular magnetic resonance of atherosclerotic carotid plaque. J Cardiovasc Magn Reson 2010; 12:17. [PMID: 20346110 PMCID: PMC2853534 DOI: 10.1186/1532-429x-12-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Accepted: 03/26/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Multi-contrast weighted cardiovascular magnetic resonance (CMR) allows detailed plaque characterisation and assessment of plaque vulnerability. The aim of this preliminary study was to show the potential of Ultra-short Echo Time (UTE) subtraction MR in detecting calcification. METHODS 14 ex-vivo human carotid arteries were scanned using CMR and CT, prior to histological slide preparation. Two images were acquired using a double-echo 3D UTE pulse, one with a long TE and the second with an ultra-short TE, with the same TR. An UTE subtraction (DeltaUTE) image containing only ultra-short T2 (and T2*) signals was obtained by post-processing subtraction of the 2 UTE images. The DeltaUTE image was compared to the conventional 3D T1-weighted sequence and CT scan of the carotid arteries. RESULTS In atheromatous carotid arteries, there was a 71% agreement between the high signal intensity areas on DeltaUTE images and CT scan. The same areas were represented as low signal intensity on T1W and areas of void on histology, indicating focal calcification. However, in 15% of all the scans there were some incongruent regions of high intensity on DeltaUTE that did not correspond with a high intensity signal on CT, and histology confirmed the absence of calcification. CONCLUSIONS We have demonstrated that the UTE sequence has potential to identify calcified plaque. Further work is needed to fully understand the UTE findings.
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Affiliation(s)
- Cheuk F Chan
- National Heart and Lung Institute, London, UK
- Cardiovascular Magnetic Resonance Imaging Department, Royal Brompton Hospital, London, UK
| | - Niall G Keenan
- National Heart and Lung Institute, London, UK
- Cardiovascular Magnetic Resonance Imaging Department, Royal Brompton Hospital, London, UK
| | - Sonia Nielles-Vallespin
- National Heart and Lung Institute, London, UK
- Cardiovascular Magnetic Resonance Imaging Department, Royal Brompton Hospital, London, UK
| | - Peter Gatehouse
- National Heart and Lung Institute, London, UK
- Cardiovascular Magnetic Resonance Imaging Department, Royal Brompton Hospital, London, UK
| | - Mary N Sheppard
- National Heart and Lung Institute, London, UK
- Cardiovascular Magnetic Resonance Imaging Department, Royal Brompton Hospital, London, UK
| | - Joseph J Boyle
- Hammersmith Hospital, Imperial College Health Care NHS Trust, London UK
| | - Dudley J Pennell
- National Heart and Lung Institute, London, UK
- Cardiovascular Magnetic Resonance Imaging Department, Royal Brompton Hospital, London, UK
| | - David N Firmin
- National Heart and Lung Institute, London, UK
- Cardiovascular Magnetic Resonance Imaging Department, Royal Brompton Hospital, London, UK
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27
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Watanabe Y, Nagayama M. MR plaque imaging of the carotid artery. Neuroradiology 2010; 52:253-74. [PMID: 20155353 DOI: 10.1007/s00234-010-0663-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 01/13/2010] [Indexed: 02/08/2023]
Abstract
Atherosclerotic carotid plaque represents a major cause of cerebral ischemia. The detection of vulnerable plaque is important for preventing future cardiovascular events. The key factors in advanced plaque that are most likely to lead to patient complications are the condition of the fibrous cap, the size of the necrotic core and hemorrhage, and the extent of inflammatory activity within the plaque. Magnetic resonance (MR) imaging has excellent soft tissue contrast and can allow for a more accurate and objective estimation of carotid wall morphology and plaque composition. Recent advances in MR imaging techniques have permitted serial monitoring of atherosclerotic disease evolution and the identification of intraplaque risk factors for accelerated progression. The purpose of this review article is to review the current state of techniques of carotid wall MR imaging and the characterization of plaque components and surface morphology with MR imaging, and to describe the clinical practice of carotid wall MR imaging for the determination of treatment plan.
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Affiliation(s)
- Yuji Watanabe
- Department of Radiology, Kurashiki Central Hospital, 1-1-1 Miwa, Kurashiki, 710-8602, Japan.
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28
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Atherosclerotic lesions rich in macrophages or smooth muscle cells discriminated in rabbit iliac arteries based on T1 relaxation time and lipid content. Acad Radiol 2010; 17:230-8. [PMID: 19910212 DOI: 10.1016/j.acra.2009.09.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 09/07/2009] [Accepted: 09/08/2009] [Indexed: 12/31/2022]
Abstract
RATIONALE AND OBJECTIVES Atherothrombosis usually occurs on macrophage- and lipid-rich unstable plaque, but rarely on smooth muscle cell (SMC)-rich stable plaque. Magnetic resonance imaging (MRI) has been extensively applied for noninvasive vascular imaging. We therefore investigated whether MRI provides valuable information about the characteristics of atherosclerotic vessels using rabbit models of macrophage-rich or SMC-rich atherosclerotic arteries. MATERIALS AND METHODS Rabbits were fed with a conventional (CD group, n = 3) or 0.5% cholesterol (ChD group, n = 3) diet for 1 week before and 3 weeks after balloon injury of the left iliac arteries. Three weeks later, these arteries were investigates by 1.5 T MRI and by conventional angiographic imaging, followed by histological and immunohistochemical analyses. RESULTS Three weeks after balloon injury, injured iliac arteries of both groups formed neointima with luminal stenosis. Conventional and MRI angiographic findings of the luminal diameter significantly and positively correlated. T1 relaxation time was significantly shorter and the lipid content was much higher in injured arteries from the ChD than from the CD group. The injured arteries from the ChD also contained more macrophages and less SMCs that those from the CD group. The T1 relaxation time and lipid content in injured arteries negatively and positively correlated with the degree of macrophage accumulation, respectively. CONCLUSION These results showed that MRI could provide valuable information about luminal stenosis and the characteristics of atherosclerotic vessels in rabbits.
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Recent developments and new perspectives on imaging of atherosclerotic plaque: role of anatomical, cellular and molecular MRI Part I and II. Int J Cardiovasc Imaging 2010; 26:433-45. [DOI: 10.1007/s10554-009-9565-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Accepted: 12/17/2009] [Indexed: 10/19/2022]
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Underhill HR, Hatsukami TS, Fayad ZA, Fuster V, Yuan C. MRI of carotid atherosclerosis: clinical implications and future directions. Nat Rev Cardiol 2010; 7:165-73. [PMID: 20101259 DOI: 10.1038/nrcardio.2009.246] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Atherosclerosis is now widely recognized as a multifactorial disease with outcomes that arise from complex factors such as plaque components, blood flow, and inflammation. Despite recent advances in understanding of plaque biology, diagnosis, and treatment, atherosclerosis remains a leading cause of morbidity and mortality. Further research into the development and validation of reliable indicators of the high-risk individual is greatly needed. Carotid MRI is a histologically validated, noninvasive imaging method that can track disease progression and regression, and quantitatively evaluate a spectrum of parameters associated with in vivo plaque morphology and composition. Intraplaque hemorrhage and the lipid-rich necrotic core are the best indicators of lesion severity currently visualized by carotid MRI. However, MRI methods capable of imaging other important aspects of carotid atherosclerotic disease in vivo-including inflammation, neovascularization, and mechanical forces-are emerging and may aid in advancing our understanding of the pathophysiology of this multifactorial disease.
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Affiliation(s)
- Hunter R Underhill
- Department of Radiology, University of Washington, 815 Mercer Street, Box 358050, Seattle, WA 98109, USA.
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31
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Oppenheim C, Naggara O, Touzé E, Lacour JC, Schmitt E, Bonneville F, Crozier S, Guégan-Massardier E, Gerardin E, Leclerc X, Neau JP, Sirol M, Toussaint JF, Mas JL, Méder JF. High-resolution MR imaging of the cervical arterial wall: what the radiologist needs to know. Radiographics 2009; 29:1413-31. [PMID: 19755603 DOI: 10.1148/rg.295085183] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The emergence of high-resolution rapid imaging methods has enabled magnetic resonance (MR) imagers to noninvasively image the fine internal structure of cervical arterial walls. In this article, a comprehensive guide to performing high-resolution MR imaging of cervical arteries is provided, including the choice of coils, sequences, and imaging parameters, as well as tips for optimal image quality. Explanations and illustrations are given of using high-resolution MR imaging to quantify plaque volume, determine atherosclerotic plaque burden, depict plaque composition, and ultimately identify unstable plaque before it leads to a clinical event. Finally, the role of high-resolution MR imaging in the diagnosis of cervical dissection and inflammatory disease of the arterial wall is emphasized.
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Affiliation(s)
- Catherine Oppenheim
- Department of Imaging, Université Paris Descartes, EA 4055, Centre Hospitalier Sainte-Anne, 1, Rue Cabanis, 75674 Paris Cedex 14, France.
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Gao H, Long Q, Graves M, Gillard JH, Li ZY. Study of reproducibility of human arterial plaque reconstruction and its effects on stress analysis based on multispectral in vivo magnetic resonance imaging. J Magn Reson Imaging 2009; 30:85-93. [PMID: 19557850 DOI: 10.1002/jmri.21799] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To quantify the uncertainties of carotid plaque morphology reconstruction based on patient-specific multispectral in vivo magnetic resonance imaging (MRI) and their impacts on the plaque stress analysis. MATERIALS AND METHODS In this study, three independent investigators were invited to reconstruct the carotid bifurcation with plaque based on MR images from two subjects to study the geometry reconstruction reproducibility. Finite element stress analyses were performed on the carotid bifurcations, as well as the models with artificially modified plaque geometries to mimic the image segmentation uncertainties, to study the impacts of the uncertainties to the stress prediction. RESULTS Plaque reconstruction reproducibility was generally high in the study. The uncertainties among interobservers are around one or the subpixel level. It also shows that the predicted stress is relatively less sensitive to the arterial wall segmentation uncertainties, and more affected by the accuracy of lipid region definition. For a model with lipid core region artificially increased by adding one pixel on the lipid region boundary, it will significantly increase the maximum Von Mises Stress in fibrous cap (>100%) compared with the baseline model for all subjects. CONCLUSION The current in vivo MRI in the carotid plaque could provide useful and reliable information for plaque morphology. The accuracy of stress analysis based on plaque geometry is subject to MRI quality. The improved resolution/quality in plaque imaging with newly developed MRI protocols would generate more realistic stress predictions.
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Affiliation(s)
- Hao Gao
- Brunel Institute for Bioengineering, Brunel University, Uxbridge, Middlesex, UK
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Gao H, Long Q, Graves M, Gillard JH, Li ZY. Carotid arterial plaque stress analysis using fluid-structure interactive simulation based on in-vivo magnetic resonance images of four patients. J Biomech 2009; 42:1416-1423. [PMID: 19464011 DOI: 10.1016/j.jbiomech.2009.04.010] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Revised: 04/06/2009] [Accepted: 04/06/2009] [Indexed: 11/18/2022]
Abstract
The rupture of atherosclerotic plaques is known to be associated with the stresses that act on or within the arterial wall. The extreme wall tensile stress (WTS) is usually recognized as a primary trigger for the rupture of vulnerable plaque. The present study used the in-vivo high-resolution multi-spectral magnetic resonance imaging (MRI) for carotid arterial plaque morphology reconstruction. Image segmentation of different plaque components was based on the multi-spectral MRI and co-registered with different sequences for the patient. Stress analysis was performed on totally four subjects with different plaque burden by fluid-structure interaction (FSI) simulations. Wall shear stress distributions are highly related to the degree of stenosis, while the level of its magnitude is much lower than the WTS in the fibrous cap. WTS is higher in the luminal wall and lower at the outer wall, with the lowest stress at the lipid region. Local stress concentrations are well confined in the thinner fibrous cap region, and usually locating in the plaque shoulder; the introduction of relative stress variation during a cycle in the fibrous cap can be a potential indicator for plaque fatigue process in the thin fibrous cap. According to stress analysis of the four subjects, a risk assessment in terms of mechanical factors could be made, which may be helpful in clinical practice. However, more subjects with patient specific analysis are desirable for plaque-stability study.
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Affiliation(s)
- Hao Gao
- Brunel Institute for Bioengineering, Brunel University, Uxbridge, Middlesex UB8 3PH, UK
| | - Quan Long
- Brunel Institute for Bioengineering, Brunel University, Uxbridge, Middlesex UB8 3PH, UK.
| | - Martin Graves
- University Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge CB2 0QQ, UK
| | - Jonathan H Gillard
- University Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge CB2 0QQ, UK
| | - Zhi-Yong Li
- University Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge CB2 0QQ, UK
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Abstract
Magnetic resonance imaging is one of the most exciting techniques for noninvasive molecular imaging of the cardiovascular system. The article will describe challenges, solutions and results of magnetic resonance plaque imaging ex-vivo, in the experimental animal and in patients.
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Affiliation(s)
- René M Botnar
- Dept. of Nuclear Medicine, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany
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Gottsegen JM, Coplan NL. The Atherosclerotic Aortic Arch: Considerations in Diagnostic Imaging. ACTA ACUST UNITED AC 2008; 11:162-7. [DOI: 10.1111/j.1751-7141.2008.08296.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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36
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High-resolution multicontrast-weighted MR imaging from human carotid endarterectomy specimens to assess carotid plaque components. Eur Radiol 2008; 18:2912-21. [DOI: 10.1007/s00330-008-1091-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2007] [Revised: 05/13/2008] [Accepted: 05/24/2008] [Indexed: 01/19/2023]
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Langer HF, Haubner R, Pichler BJ, Gawaz M. Radionuclide imaging: a molecular key to the atherosclerotic plaque. J Am Coll Cardiol 2008; 52:1-12. [PMID: 18582628 DOI: 10.1016/j.jacc.2008.03.036] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 03/20/2008] [Accepted: 03/24/2008] [Indexed: 01/09/2023]
Abstract
Despite primary and secondary prevention, serious cardiovascular events such as unstable angina or myocardial infarction still account for one-third of all deaths worldwide. Therefore, identifying individual patients with vulnerable plaques at high risk for plaque rupture is a central challenge in cardiovascular medicine. Several noninvasive techniques, such as magnetic resonance imaging, multislice computed tomography, and electron beam tomography are currently being tested for their ability to identify such patients by morphological criteria. In contrast, molecular imaging techniques use radiolabeled molecules to detect functional aspects in atherosclerotic plaques by visualizing their biological activity. Based upon the knowledge about the pathophysiology of atherosclerosis, various studies in vitro and in vivo and the first clinical trials have used different tracers for plaque imaging studies, including radioactive-labeled lipoproteins, components of the coagulation system, cytokines, mediators of the metalloproteinase system, cell adhesion receptors, and even whole cells. This review gives an update on the relevant noninvasive plaque imaging approaches using nuclear imaging techniques to detect atherosclerotic vascular lesions.
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Affiliation(s)
- Harald F Langer
- Medizinische Klinik III, Eberhard Karls Universität Tübingen, Tübingen, Germany.
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38
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Bluemke DA, Achenbach S, Budoff M, Gerber TC, Gersh B, Hillis LD, Hundley WG, Manning WJ, Printz BF, Stuber M, Woodard PK. Noninvasive coronary artery imaging: magnetic resonance angiography and multidetector computed tomography angiography: a scientific statement from the american heart association committee on cardiovascular imaging and intervention of the council on cardiovascular radiology and intervention, and the councils on clinical cardiology and cardiovascular disease in the young. Circulation 2008; 118:586-606. [PMID: 18586979 DOI: 10.1161/circulationaha.108.189695] [Citation(s) in RCA: 351] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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39
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IRM haute résolution de l’athérosclérose carotidienne :au-delà de la lumière artérielle. ACTA ACUST UNITED AC 2008; 89:293-301. [DOI: 10.1016/s0221-0363(08)93003-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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40
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Choi BG, Vilahur G, Zafar MU, Cardoso L, Yadegar D, Ibanez B, Tunstead J, Viles-Gonzalez JF, Schaffler MB, Fuster V, Badimon JJ. Selective estrogen receptor modulation influences atherosclerotic plaque composition in a rabbit menopause model. Atherosclerosis 2008; 201:76-84. [PMID: 18367192 DOI: 10.1016/j.atherosclerosis.2008.01.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Revised: 12/23/2007] [Accepted: 01/23/2008] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Osteoporosis trials suggest raloxifene decreased cardiovascular events in women with pre-existing atherosclerosis. We assessed the hypothesis that selective estrogen receptor modulation induces plaque stability in "menopausal" animals. METHODS AND RESULTS Atherosclerosis was induced in 42 ovariectomized New Zealand white rabbits by cholesterol feeding and mechanical injury. Animals were imaged by magnetic resonance imaging (MRI) for baseline atherosclerosis, and randomized to control (OVX (ovariectomized control group), n=12), raloxifene 35-60 mg/kg/day by diet admixture (RLX (raloxifene therapy group), n=24), or immediate sacrifice (n=6) for immunohistopathologic correlation of MRI. Six months later, rabbits underwent repeat MRI then sacrifice for micro-computed tomography (microCT) and molecular analysis. Unlike OVX, RLX reduced atheroma volume. Analysis for lesion inflammation revealed reductions in COX-2 (cyclooxygenase-2), MMP-1 (matrix metalloproteinase-1), MCP-1 (monocyte chemoattractant protein-1) expression and macrophage infiltration in RLX versus OVX with concomitant upregulation of estrogen receptor alpha (ERalpha). microCT showed similar total vascular calcification between groups, but calcifications in RLX were less nodular with better radial organization (mean calcific arc angle 63+/-7 degrees versus 33+/-6 degrees in OVX), the predicted result of a 53% increase in BMP-2 (bone-morphogenetic protein-2). CONCLUSIONS Raloxifene treatment results in reduced lesion volume, enhanced mechanical stability of vascular calcification, and less inflamed lesions characterized by less macrophage infiltration and reduced COX-2, MMP-1 and MCP-1 expression.
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Affiliation(s)
- Brian G Choi
- Cardiovascular Biology Research Laboratory, Mount Sinai School of Medicine, New York, NY, USA
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41
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Oyama N, Gona P, Salton CJ, Chuang ML, Jhaveri RR, Blease SJ, Manning AR, Lahiri M, Botnar RM, Levy D, Larson MG, O'Donnell CJ, Manning WJ. Differential impact of age, sex, and hypertension on aortic atherosclerosis: the Framingham Heart Study. Arterioscler Thromb Vasc Biol 2007; 28:155-9. [PMID: 17991874 DOI: 10.1161/atvbaha.107.153544] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE The purpose of this study was to investigate the impact of age, sex, and hypertension (HTN) on aortic atherosclerotic burden using cardiovascular MRI (CMR) in a free-living longitudinally followed cohort. METHODS AND RESULTS 1763 participants (829 M and 934 F; 38 to 88 years of age) of the Framingham Heart Study Offspring cohort underwent CMR of the thoracoabdominal aorta using an ECG-gated 2D T2-weighted black-blood sequence. Of these, 1726 subjects (96%) with interpretable CMR were characterized by sex, age-quartile, and presence or absence of HTN and clinical cardiovascular disease (CVD). Aortic plaque prevalence and volume increased with increasing age in both sexes. For the nonhypertensive (no-HTN) group, plaque was identified in 702 (46%) with greater prevalence in women than in men (P<0.006). HTN was associated with greater aortic plaque burden (P<0.02). The 200 subjects with clinical CVD had greater plaque burden than subjects without CVD (P<0.0001). CONCLUSIONS In this free-living longitudinally followed cohort, subclinical aortic atherosclerosis was seen in nearly half of subjects and increased with advancing age. HTN was associated with increased aortic plaque burden. Among no-HTN subjects, women had greater plaque burden than men. These data suggest that subclinical atherosclerosis is more common in no-HTN women and emphasize the importance of focusing on preventive measures in both sexes.
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Affiliation(s)
- Noriko Oyama
- Departments of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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Touzé E, Toussaint JF, Coste J, Schmitt E, Bonneville F, Vandermarcq P, Gauvrit JY, Douvrin F, Meder JF, Mas JL, Oppenheim C. Reproducibility of high-resolution MRI for the identification and the quantification of carotid atherosclerotic plaque components: consequences for prognosis studies and therapeutic trials. Stroke 2007; 38:1812-9. [PMID: 17463311 DOI: 10.1161/strokeaha.106.479139] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Although MRI is increasingly proposed to investigate composition of carotid atherosclerosis, its reproducibility has rarely been addressed. We assessed the reproducibility of MRI for the identification and quantification of carotid atherosclerotic plaque components. METHODS Using published criteria, 2 readers independently analyzed the carotid MRI (1.5-T MR units with a 4-channel phased-array surface coil, Machnet) of 85 consecutive patients with symptomatic (40% to 69% according to NASCET method) or asymptomatic (60% or greater) carotid artery stenosis enrolled in an ongoing prognostic study. One reader reevaluated all images. Fibrous cap was also secondarily identified independently on T2-weighted and time-of-flight (TOF) images. RESULTS Intraobserver agreement was substantial for the identification of calcifications (kappa [kappa]=0.70; 95% CI: 0.54 to 0.86) and lipid-rich/necrotic core (LR/NC) (kappa=0.69; 0.31 to 0.86), almost perfect for hemorrhages (kappa=0.82; 0.68 to 0.96), and moderate (kappa=0.58; 0.27 to 0.88) and fair (kappa=0.33; 0.09 to 0.56) for fibrous cap identification on T2-weighted and TOF images, respectively. Interobserver agreement was substantial for the identification of calcifications (kappa=0.74; 0.59 to 0.89) and hemorrhages (kappa=0.62; 0.43 to 0.81), and moderate for LR/NC (kappa=0.58; 0.20 to 0.95). Agreement was fair for fibrous cap identification on both T2-weighted (kappa=0.28; -0.03 to 0.59) and on TOF images (kappa=0.26; 0.04 to 0.48). Agreement between T2 and TOF images for fibrous cap identification was slight (kappa=0.16; 0.01 to 0.31). Intra- and interobserver reproducibility for quantitative area measurements of vessel, lumen, plaque, LR/NC, and fibrous components was high with intraclass correlation coefficients ranging from 0.73 to 0.99. However, for the LR/NC, the interval delimited by the Bland-Altman graphs was wide in comparison to the mean. CONCLUSIONS Vessel and plaque quantification is reproducible. Reproducibility of MRI for identifying and quantifying carotid plaque components is overall acceptable, but there is still significant variability that should be taken into account in the design of prognosis studies and clinical trials. Reproducibility for fibrous cap identification needs to be improved.
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Affiliation(s)
- Emmanuel Touzé
- Faculté de Médecine Paris-Descartes, Department of Neurology, Centre Hospitalier Sainte-Anne, Paris Cedex 14, France.
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Qiao Y, Ronen I, Viereck J, Ruberg FL, Hamilton JA. Identification of atherosclerotic lipid deposits by diffusion-weighted imaging. Arterioscler Thromb Vasc Biol 2007; 27:1440-6. [PMID: 17379838 PMCID: PMC2910580 DOI: 10.1161/atvbaha.107.141028] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES The content and distribution of lipids is an important aspect of plaque vulnerability, but lipids are present within a heterogeneous environment, impeding detection by magnetic resonance imaging. Our goal was to achieve accurate detection of mobile lipids by a single magnetic resonance imaging sequence. METHODS AND RESULTS Carotid endarectomy specimens (n=23) were imaged ex vivo at a high magnetic field (11.7 T) within 24 hours after surgery. Three contrast-weighted (T1W, T2W, and diffusion-weighted imaging [DWI]) image sequences were acquired and then coregistered with histological preparations for lipids (Oil red O and polarized light microscopy) and fibrous tissue (trichrome). Contrast-to-noise ratios were measured and compared for the 3 contrast weightings. Contrast-to-noise ratio measurement in regions identified as lipid versus fibrous tissue showed greater differences by DWI (4.5+/-0.63 versus 0.64+/-0.08; P<0.05) as compared with T2W (2.83+/-0.36 versus 1.36+/-0.37; P<0.05). We validated the presence and distribution of lipids (mainly cholesteryl esters) by both histology and image-guide spectroscopy. The basis for distinguishing mobile lipid and water inside the plaque was illustrated by diffusion-weighted spectroscopy. CONCLUSIONS Biophysical properties of plaque lipids can confer selective identification by DWI, as opposed to standard T1W and T2W imaging sequences. Successful translation of DWI in vivo could identify of features of vulnerable plaque.
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Affiliation(s)
- Ye Qiao
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118, USA
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44
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Botvinick EH, Perini R, Bural G, Chen W, Chryssikos T, Houseni M, Hernandez-Pampaloni M, Torigian DA, Alavi A. The aging of the heart and blood vessels: a consideration of anatomy and physiology in the era of computed tomography, magnetic resonance imaging, and positron emission tomographic imaging methods with special consideration of atherogenesis. Semin Nucl Med 2007; 37:120-43. [PMID: 17289459 DOI: 10.1053/j.semnuclmed.2006.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Physicians have long told their patients that the doctor's job is to help patients "get as old as they can." As physicians, we have been aided in this objective by many other scientists in other disciplines. The entity of aging and its related changes blends imperceptibly with a variety of age-related diseases. However, these entities do appear to be separate though interrelated. Curing disease is important and a goal that we all work toward to add years to life expectancy. Here, we consider aging as it affects the heart and great vessels and as it serves to influence and support, if not cause, age-related cardiac diseases. This relationship is drawn as cardiac mechanics, hemodynamics, perfusion, metabolism and innervation, anatomy, and pathophysiology are each considered. The effects of aging are presented in 2 sections related to the early and recent "spikes" in aging related information. The latter is largely based in recent developments in chemistry, genetic engineering, molecular biology and the new imaging methods. The purpose of this manuscript is to present these new imaging methods, especially PET, and their impact on the second "spike." This is emphasized particularly in the second half of this review. As a method of demonstrating these imaging tools and their finest potential application, we decided to "showcase" atherosclerosis as the age-related disease for which these methods have made their greatest impact, for which yet more is promised, and for which the influence on longevity is most obvious. The application of positron emission tomography and other imaging methods to the characterization and image identification of atherosclerotic plaques and particularly the "vulnerable" plaque is emphasized. Yet, even with the eradication of coronary disease, the potential for very long life would not be likely. Only with the identification and eradication of the causative factors of aging can this possibility have a chance of becoming reality.
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Affiliation(s)
- Eli H Botvinick
- Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
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45
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Abstract
Atherosclerosis is a prevalent disease affecting millions of Americans. Despite our advances in diagnosis and treatment, atherosclerosis is the leading cause of death in America. High-resolution magnetic resonance imaging has overcome the limitations of current angiographic techniques and has emerged as a leading noninvasive imaging modality for atherosclerotic disease. Atherosclerosis of the arterial wall of the human carotid, aortic, peripheral and coronary arteries have all been successfully evaluated. In addition, the power of magnetic resonance imaging to differentiate the major components of atherosclerotic plaque has been validated. The ability to image the vessel wall and risk stratify atherosclerotic plaque will create management decisions not previously faced, and has the potential to change the way atherosclerosis is treated.
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Affiliation(s)
- Christopher M Kramer
- University of Virginia Health System, Department of Medicine, Lee Street, Box 800170, Charlottesville, VA 22908, USA.
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46
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Magnetic Resonance Angiography and Evaluation of Vulnerable Plaque. CARDIOVASCULAR MEDICINE 2007. [DOI: 10.1007/978-1-84628-715-2_40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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47
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Sun B, Giddens DP, Long R, Taylor WR, Weiss D, Joseph G, Vega D, Oshinski JN. Automatic plaque characterization employing quantitative and multicontrast MRI. Magn Reson Med 2007; 59:174-80. [DOI: 10.1002/mrm.21279] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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48
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Jahnke C, Dietrich T, Paetsch I, Koehler U, Preetz K, Schnackenburg B, Fleck E, Graf K, Nagel E. Experimental evaluation of the detectability of submillimeter atherosclerotic lesions in ex vivo human iliac arteries with ultrahigh-field (7.0 T) magnetic resonance imaging. Int J Cardiovasc Imaging 2006; 23:519-27. [PMID: 17109199 DOI: 10.1007/s10554-006-9185-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2006] [Accepted: 10/17/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND To evaluate the ability of ultrahigh-field magnetic resonance imaging (MRI) to accurately depict the composition of the human arterial vessel wall ex vivo and to detect early atherosclerotic lesion formation in comparison to histology. METHODS Eight iliac artery specimens with low-grade atherosclerotic lesions obtained from human organ donors were studied. Three-dimensional, high-resolution MRI (spatial resolution: 79 x 79 x 109 microm) was performed using T1-, T2- and proton density (PD)-weightings (7.0 Tesla MR system, Bruker Pharmascan). A total of 36 MR slices and corresponding histological sections were matched for comparative evaluation of area measurements of lumen, media and adventitia and--if present--plaque size. Statistical correlation between histology and MR measurements was tested and a ROC-analysis was performed to determine the plaque size being predictive of correctly identifying atherosclerotic lesions with MRI. RESULTS The areas of vessel lumen and media as measured on T1-, T2- and PD-weighted MR images showed a strong correlation with the corresponding histological measurements (r = 0.84 to r = 0.89; P < 0.01), however, a systematic overestimation of 34-41% was found. For the area of adventitia, only a moderate, though significant, correlation (r = 0.55 to r = 0.62; P < 0.01) could be demonstrated with a similar overestimation by MRI (38-43%). With T1-weighted MRI, sensitivity and specificity for the detection of plaques > 4.0 mm(2) were 79% and 91%, respectively. With T2- and PD-weighted MRI, however, sensitivity and specificity for the detection of plaques > 0.4 mm2 were 93% and 89%. CONCLUSIONS In an experimental ex vivo setting, ultrahigh-field MRI of the human arterial vessel wall resulted in an accurate visualization of vessel wall composition when compared to histology and, thus, allowed for a quantitative assessment. T2- and PD-weighted MRI proved capable of reliably detecting submillimeter atherosclerotic lesions.
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Affiliation(s)
- Cosima Jahnke
- Department of Internal Medicine/Cardiology, German Heart Institute Berlin, Augustenburger Platz 1, 13353 Berlin, Germany.
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Chow BJW, Veinot JP. What are the most useful and trustworthy noninvasive anatomic markers of existing vascular disease? Curr Cardiol Rep 2006; 8:439-45. [PMID: 17059796 DOI: 10.1007/s11886-006-0102-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cardiovascular disease is the leading cause of mortality and morbidity in developed countries. Evidence challenges the notion that the severity of lesions on angiography is a predictor of future cardiac events. With the recognition that subclinical coronary artery stenoses are responsible for myocardial infarcts and sudden death, it may be important to identify patients with plaque characteristics that may place them at increased risk. Intravascular ultrasound, though invasive, remains the current imaging gold standard. Computed tomography, cardiac magnetic resonance, and single-photon emission CT positron emission tomography are evolving and promising modalities. Functional studies reflecting plaque temperature and molecular imaging reflecting plaque constituents are being developed. We review the pathology of the vulnerable atherosclerotic plaque and recent innovations in imaging modalities to assess plaque complication risk.
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Affiliation(s)
- Benjamin J W Chow
- Department of Laboratory Medicine, Room 123, Ottawa Hospital, Civic Campus, 1053 Carling Avenue, Ottawa, Ontario K1Y 4E9, Canada
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50
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Desai MY, Lima JAC. Imaging of atherosclerosis using magnetic resonance: state of the art and future directions. Curr Atheroscler Rep 2006; 8:131-9. [PMID: 16510047 DOI: 10.1007/s11883-006-0050-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Atherosclerosis is the leading cause of morbidity and mortality in industrialized societies, and its incidence is projected to increase in the future. Because the atherosclerotic process begins in the vessel wall, the focus of cardiovascular imaging is shifting from the arterial lumen to imaging of the vessel wall, with the goal of detecting preclinical atherosclerosis. MRI, because of its high resolution, three-dimensional capabilities, noninvasive nature, and capacity for soft tissue characterization, is emerging as an important modality to assess the atherosclerotic plaque burden in the arterial wall and can monitor atherosclerosis in different arterial beds, including the carotid arteries, aorta, and more recently, the coronary arteries. Furthermore, it has also been successfully utilized to monitor plaque regression following therapeutic interventions. Finally, the emergence of high-resolution MRI and development of sophisticated contrast agents offers tremendous promise for in vivo molecular imaging of the atherosclerotic plaque.
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Affiliation(s)
- Milind Y Desai
- Division of Cardiology, Johns Hopkins University, Baltimore, MD 21287, USA
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