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Krittayaphong R, Zhang S, Tanapibunpon P, Kaolawanich Y, Nakyen S. Dark-blood late gadolinium-enhancement cardiac magnetic resonance imaging for myocardial scar detection based on simplified timing scheme: single-center experience in patients with suspected coronary artery disease. Quant Imaging Med Surg 2022; 12:1037-1050. [PMID: 35111603 DOI: 10.21037/qims-21-704] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 10/08/2021] [Indexed: 12/15/2022]
Abstract
Background This study aims to examine scar detectability using dark-blood late gadolinium enhancement (LGE) with simplified timing scheme and fixed parameters comparing to two conventional bright-blood approaches in patients with known or suspected coronary artery disease. Methods Three LGE techniques were performed in all patients with known or suspected coronary artery disease at 3 T: dark blood two-dimensional (2D) phase-sensitive inversion recovery (PSIR) preceded with a T2-preparation pulse (DB-LGE), conventional three-dimensional (3D) gradient-echo inversion recovery (3D-IR) and conventional 2D PSIR. Timing parameters in DB-LGE were tested in five clinically confirmed coronary artery disease patients with scars and fixed for the rest of the study. Two independent readers evaluated images at both patient and segment levels. Image quality and contrast ratio between scar and adjacent tissues were assessed. Concordance between the three techniques and detection rate based on expert consensus were reported. Results Forty-six patients were recruited in the study (average age 66.8 years, 69.6% male). DB-LGE demonstrated superior image quality (P=0.001 vs. 3D-IR) and scar-to-blood contrast ratio (P<0.001 vs. 3D-IR and PSIR). Among 41 patients with suspected coronary artery disease, myocardial scar was present in 30 patients (73.2%), all detected by DB-LGE, yielding a detection rate of 100% compared to 93.3% and 96.7% for bright-blood 3D-IR and PSIR. For subendocardial scar detection among 656 segments, DB-LGE had a detection rate of 99.4% compared to 57.8% for 3D-IR and 61.0% for PSIR (both P<0.001). Conclusions DB-LGE improves detection of myocardial scar compared with conventional bright-blood LGE techniques, particularly of subendocardial scar.
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Affiliation(s)
- Rungroj Krittayaphong
- Division of Cardiology, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Shuo Zhang
- Philips Healthcare, Singapore.,Philips Healthcare, Hamburg, Germany
| | - Prajak Tanapibunpon
- Her Majesty Cardiac Center, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Yodying Kaolawanich
- Division of Cardiology, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Supaporn Nakyen
- Her Majesty Cardiac Center, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
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Imaging Features of Vulnerable Carotid Atherosclerotic Plaque and the Associated Clinical Implications. CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2020. [DOI: 10.1007/s11936-020-00821-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Ludwig DR, Shetty AS, Broncano J, Bhalla S, Raptis CA. Magnetic Resonance Angiography of the Thoracic Vasculature: Technique and Applications. J Magn Reson Imaging 2020; 52:325-347. [PMID: 32061029 DOI: 10.1002/jmri.27067] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/05/2020] [Accepted: 01/07/2020] [Indexed: 12/12/2022] Open
Abstract
Magnetic resonance angiography (MRA) is a powerful clinical tool for evaluation of the thoracic vasculature. MRA can be performed on nearly any magnetic resonance imaging (MRI) scanner, and provides images of high diagnostic quality without the use of ionizing radiation. While computed tomographic angiography (CTA) is preferred in the evaluation of hemodynamically unstable patients, MRA represents an important tool for evaluation of the thoracic vasculature in stable patients. Contrast-enhanced MRA is generally performed unless there is a specific contraindication, as it shortens the duration of the exam and provides images of higher diagnostic quality than noncontrast MRA. However, intravenous contrast is often not required to obtain a diagnostic evaluation for most clinical indications. Indeed, a variety of noncontrast MRA techniques are used for thoracic imaging, often in conjunction with contrast-enhanced MRA, each of which has a differing degree of reliance on flowing blood to produce the desired vascular signal. In this article we review contrast-enhanced MRA, with a focus on contrast agents, methods of bolus timing, and considerations in imaging acquisition. Next, we cover the mechanism of contrast, strengths, and weaknesses of various noncontrast MRA techniques. Finally, we present an approach to protocol development and review representative protocols used at our institution for a variety of thoracic applications. Further attention will be devoted to additional techniques employed to address specific clinical questions, such as delayed contrast-enhanced imaging, provocative maneuvers, electrocardiogram and respiratory gating, and phase-contrast imaging. The purpose of this article is to review basic techniques and methodology in thoracic MRA, discuss an approach to protocol development, and illustrate commonly encountered pathology on thoracic MRA examinations. Level of Evidence 5 Technical Efficacy Stage 3.
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Affiliation(s)
- Daniel R Ludwig
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Anup S Shetty
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jordi Broncano
- Cardiothoracic Imaging Section, Health Time, Hospital de la Cruz Roja and San Juan de Dios, Cordoba, Spain
| | - Sanjeev Bhalla
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Constantine A Raptis
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
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Kern KC, Liebeskind DS. Vessel Wall Imaging of Cerebrovascular Disorders. CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2019; 21:65. [DOI: 10.1007/s11936-019-0782-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Aldweib N, Farah V, Biederman RWW. Clinical Utility of Cardiac Magnetic Resonance Imaging in Pericardial Diseases. Curr Cardiol Rev 2018; 14:200-212. [PMID: 29921208 PMCID: PMC6131401 DOI: 10.2174/1573403x14666180619104515] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/28/2018] [Accepted: 06/12/2018] [Indexed: 12/18/2022] Open
Abstract
Background: Pericardial diseases are relatively common in clinical practice and encountered in various clinical settings with consequent significant morbidity and mortality. However, the diagnosis as well as management can be complex and challenging, as the clinical presentation is usually non-specific. Therefore, there is an increasing role for Cardiac Magnetic Resonance Imaging (CMR) as an imaging tool to facilitate the diagnosis of pericardial diseases. Conclusion: Herein we describe conventional and unique CMR approaches to provide an increased non-invasive understanding of the pericardium in health and disease including a novel method to diagnose constrictive pericarditis via radio-frequency tissue tagging by defining unique visceral-parietal adherence patterns easily learned by the cardiologist and radiologist.
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Affiliation(s)
- Nael Aldweib
- Division of Cardiology, Center for Cardiac MRI. Allegheny General Hospital, East North Ave, Pittsburgh, PA, United States
| | - Victor Farah
- Division of Cardiology, Center for Cardiac MRI. Allegheny General Hospital, East North Ave, Pittsburgh, PA, United States
| | - Robert W W Biederman
- Division of Cardiology, Center for Cardiac MRI. Allegheny General Hospital, East North Ave, Pittsburgh, PA, United States
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Keerthivasan MB, Mandava S, Johnson K, Avery R, Janardhanan R, Martin DR, Bilgin A, Altbach MI. A multi-band double-inversion radial fast spin-echo technique for T2 cardiovascular magnetic resonance mapping of the heart. J Cardiovasc Magn Reson 2018; 20:49. [PMID: 30025523 PMCID: PMC6052643 DOI: 10.1186/s12968-018-0470-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 06/14/2018] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Double inversion recovery (DIR) fast spin-echo (FSE) cardiovascular magnetic resonance (CMR) sequences are used clinically for black-blood T2-weighted imaging. However, these sequences suffer from slice inefficiency due to the non-selective inversion pulses. We propose a multi-band (MB) encoded DIR radial FSE (MB-DIR-RADFSE) technique to simultaneously excite two slices. This sequence has improved signal-to-noise ratio per unit time compared to a single slice excitation. It is also motion robust and enables the reconstruction of high-resolution black-blood T2-weighted images and T2 maps for the excited slices. METHODS Hadamard encoded MB pulses were used in MB-DIR-RADFSE to simultaneously excite two slices. A principal component based iterative reconstruction was used to jointly reconstruct black-blood T2-weighted images and T2 maps. Phantom and in vivo experiments were performed to evaluate T2 mapping performance and results were compared to a T2-prepared balanced steady state free precession (bSSFP) method. The inter-segment variability of the T2 maps were assessed using data acquired on healthy subjects. A reproducibility study was performed to evaluate reproducibility of the proposed technique. RESULTS Phantom experiments show that the T2 values estimated from MB-DIR-RADFSE are comparable to the spin-echo based reference, while T2-prepared bSSFP over-estimated T2 values. The relative contrast of the black-blood images from the multi-band scheme was comparable to those from a single slice acquisition. The myocardial segment analysis on 8 healthy subjects indicated a significant difference (p-value < 0.01) in the T2 estimates from the apical slice when compared to the mid-ventricular slice. The mean T2 estimate from 12 subjects obtained using T2-prepared bSSFP was significantly higher (p-value = 0.012) compared to MB-DIR-RADFSE, consistent with the phantom results. The Bland-Altman analysis showed excellent reproducibility between the MB-DIR-RADFSE measurements, with a mean T2 difference of 0.12 ms and coefficient of reproducibility of 2.07 in 15 clinical subjects. The utility of this technique is demonstrated in two subjects where the T2 maps show elevated values in regions of pathology. CONCLUSIONS The use of multi-band pulses for excitation improves the slice efficiency of the double inversion fast spin-echo pulse sequence. The use of a radial trajectory and a joint reconstruction framework allows reconstruction of TE images and T2 maps for the excited slices.
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Affiliation(s)
- Mahesh Bharath Keerthivasan
- Department of Electrical and Computer Engineering, University of Arizona, Tucson, AZ USA
- Department of Medical Imaging, University of Arizona, Tucson, AZ USA
| | - Sagar Mandava
- Department of Electrical and Computer Engineering, University of Arizona, Tucson, AZ USA
| | | | - Ryan Avery
- Department of Medical Imaging, University of Arizona, Tucson, AZ USA
| | | | - Diego R. Martin
- Department of Medical Imaging, University of Arizona, Tucson, AZ USA
| | - Ali Bilgin
- Department of Electrical and Computer Engineering, University of Arizona, Tucson, AZ USA
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ USA
| | - Maria I. Altbach
- Department of Medical Imaging, University of Arizona, Tucson, AZ USA
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Li B, Li H, Kong H, Dong L, Zhang J, Fang J. Compressed sensing based simultaneous black- and gray-blood carotid vessel wall MR imaging. Magn Reson Imaging 2017; 38:214-223. [DOI: 10.1016/j.mri.2017.01.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 01/17/2017] [Accepted: 01/17/2017] [Indexed: 10/20/2022]
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Kim J, Park JE, Nahrendorf M, Kim DE. Direct Thrombus Imaging in Stroke. J Stroke 2016; 18:286-296. [PMID: 27733029 PMCID: PMC5066439 DOI: 10.5853/jos.2016.00906] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/01/2016] [Accepted: 09/17/2016] [Indexed: 01/02/2023] Open
Abstract
There is an emergent need for imaging methods to better triage patients with acute stroke for tissue-plasminogen activator (tPA)-mediated thrombolysis or endovascular clot retrieval by directly visualizing the size and distribution of cerebral thromboemboli. Currently, magnetic resonance (MR) or computed tomography (CT) angiography visualizes the obstruction of blood flow within the vessel lumen rather than the thrombus itself. The present visualization method, which relies on observation of the dense artery sign (the appearance of cerebral thrombi on a non-enhanced CT), suffers from low sensitivity. When translated into the clinical setting, direct thrombus imaging is likely to enable individualized acute stroke therapy by allowing clinicians to detect the thrombus with high sensitivity, assess the size and nature of the thrombus more precisely, serially monitor the therapeutic effects of thrombolysis, and detect post-treatment recurrence. This review is intended to provide recent updates on stroke-related direct thrombus imaging using MR imaging, positron emission tomography, or CT.
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Affiliation(s)
- Jongseong Kim
- Molecular Imaging and Neurovascular Research (MINER) Laboratory, Dongguk University Ilsan Hospital, Goyang, Korea.,Global Research Laboratory for Thrombus-targeted Theranostics at Dongguk University Ilsan Hospital (Korea) and Massachusetts General Hospital ( USA )
| | - Jung E Park
- Department of Neurology, Dongguk University Ilsan Hospital, Goyang, Korea
| | - Matthias Nahrendorf
- Global Research Laboratory for Thrombus-targeted Theranostics at Dongguk University Ilsan Hospital (Korea) and Massachusetts General Hospital ( USA ).,Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Dong-Eog Kim
- Molecular Imaging and Neurovascular Research (MINER) Laboratory, Dongguk University Ilsan Hospital, Goyang, Korea.,Global Research Laboratory for Thrombus-targeted Theranostics at Dongguk University Ilsan Hospital (Korea) and Massachusetts General Hospital ( USA ).,Department of Neurology, Dongguk University Ilsan Hospital, Goyang, Korea
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Matsushige T, Akiyama Y, Okazaki T, Shinagawa K, Ichinose N, Awai K, Kurisu K. Vascular Wall Imaging of Unruptured Cerebral Aneurysms with a Hybrid of Opposite-Contrast MR Angiography. AJNR Am J Neuroradiol 2015; 36:1507-11. [PMID: 25929881 DOI: 10.3174/ajnr.a4318] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 01/09/2015] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Inflammation and degeneration of the intracranial saccular aneurysm wall play a major role in aneurysm formation, development and subsequent rupture. The aim of this study was to characterize the walls of unruptured intracranial aneurysms by using a hybrid of opposite-contrast MRA at 3T. MATERIALS AND METHODS Fourteen consecutive patients with 17 unruptured intracranial aneurysms who initially underwent clipping surgery were prospectively evaluated. All aneurysms were scanned preoperatively by using a hybrid of opposite-contrast MRA in 3T high-resolution MR imaging. We classified intraoperative findings of atherosclerotic plaques in the aneurysms into 3 grades: grade A (major plaques), grade B (minor plaques), and grade C (no plaques). The contrast ratio of the high-intensity area was also measured relative to the background low-intensity area inside the carotid artery. RESULTS Findings from preoperative plaque imaging of the aneurysm corresponded to the intraoperative findings in 15 of 16 aneurysms (excluding 1 that was impossible to visualize in its entirety due to anatomic reasons). Overall sensitivity and specificity of the hybrid of opposite-contrast MRA were 88.9% and 100%, respectively. During the operation, 4 aneurysms were classified as grade A; 5, as grade B; and 7, as grade C. The means of the contrast ratio for grades A, B, and C were 0.72 ± 0.03, 0.34 ± 0.30, and -0.02 ± 0.09, respectively. CONCLUSIONS The hybrid of opposite-contrast MRA can detect visible atherosclerotic plaques in the unruptured aneurysm wall, and the contrast ratio in intracranial aneurysms correlated with their presence and extent. A study including a larger series is needed to validate the diagnostic potential of this imaging technique.
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Affiliation(s)
- T Matsushige
- From the Department of Neurosurgery (T.M., T.O., K.S., N.I., K.K.), Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan Department of Neurosurgery (T.M.), University Hospital Essen, Essen, Germany
| | - Y Akiyama
- Department of Diagnostic Radiology (Y.A., K.A.), Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - T Okazaki
- From the Department of Neurosurgery (T.M., T.O., K.S., N.I., K.K.), Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - K Shinagawa
- From the Department of Neurosurgery (T.M., T.O., K.S., N.I., K.K.), Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - N Ichinose
- From the Department of Neurosurgery (T.M., T.O., K.S., N.I., K.K.), Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - K Awai
- Department of Diagnostic Radiology (Y.A., K.A.), Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - K Kurisu
- From the Department of Neurosurgery (T.M., T.O., K.S., N.I., K.K.), Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
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Phase-Sensitive Dual-Inversion Recovery for Accelerated Carotid Vessel Wall Imaging. Invest Radiol 2015; 50:135-43. [DOI: 10.1097/rli.0000000000000110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Li L, Chai JT, Biasiolli L, Robson MD, Choudhury RP, Handa AI, Near J, Jezzard P. Black-Blood Multicontrast Imaging of Carotid Arteries with DANTE-prepared 2D and 3D MR Imaging. Radiology 2014; 273:560-9. [DOI: 10.1148/radiol.14131717] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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12
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Quantitative magnetic resonance imaging of pulmonary hypertension: a practical approach to the current state of the art. J Thorac Imaging 2014; 29:68-79. [PMID: 24552882 DOI: 10.1097/rti.0000000000000079] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Pulmonary hypertension is a condition of varied etiology, commonly associated with poor clinical outcome. Patients are categorized on the basis of pathophysiological, clinical, radiologic, and therapeutic similarities. Pulmonary arterial hypertension (PAH) is often diagnosed late in its disease course, with outcome dependent on etiology, disease severity, and response to treatment. Recent advances in quantitative magnetic resonance imaging (MRI) allow for better initial characterization and measurement of the morphologic and flow-related changes that accompany the response of the heart-lung axis to prolonged elevation of pulmonary arterial pressure and resistance and provide a reproducible, comprehensive, and noninvasive means of assessing the course of the disease and response to treatment. Typical features of PAH occur primarily as a result of increased pulmonary vascular resistance and the resultant increased right ventricular (RV) afterload. Several MRI-derived diagnostic markers have emerged, such as ventricular mass index, interventricular septal configuration, and average pulmonary artery velocity, with diagnostic accuracy similar to that of Doppler echocardiography. Furthermore, prognostic markers have been identified with independent predictive value for identification of treatment failure. Such markers include large RV end-diastolic volume index, low left ventricular end-diastolic volume index, low RV ejection fraction, and relative area change of the pulmonary trunk. MRI is ideally suited for longitudinal follow-up of patients with PAH because of its noninvasive nature and high reproducibility and is advantageous over other biomarkers in the study of PAH because of its sensitivity to change in morphologic, functional, and flow-related parameters. Further study on the role of MRI image based biomarkers in the clinical environment is warranted.
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Dyverfeldt P, Deshpande VS, Kober T, Krueger G, Saloner D. Reduction of motion artifacts in carotid MRI using free-induction decay navigators. J Magn Reson Imaging 2013; 40:214-20. [PMID: 24677562 DOI: 10.1002/jmri.24389] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 07/10/2013] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To develop a framework for prospective free-induction decay (FID)-based navigator gating for suppression of motion artifacts in carotid magnetic resonance imaging (MRI) and to assess its capability in vivo. MATERIALS AND METHODS An FID-navigator, comprising a spatially selective low flip-angle sinc-pulse followed by an analog-to-digital converter (ADC) readout, was added to a conventional turbo spin-echo (TSE) sequence. Real-time navigator processing delivered accept/reject-and-reacquire decisions to the sequence. In this Institutional Review Board (IRB)-approved study, seven volunteers were scanned with a 2D T2-weighted TSE sequence. A reference scan with volunteers instructed to minimize motion as well as nongated and gated scans with volunteers instructed to perform different motion tasks were performed in each subject. Multiple image quality measures were employed to quantify the effect of gating. RESULTS There was no significant difference in lumen-to-wall sharpness (2.3 ± 0.3 vs. 2.3 ± 0.4), contrast-to-noise ratio (CNR) (9.0 ± 2.0 vs. 8.5 ± 2.0), or image quality score (3.1 ± 0.9 vs. 2.6 ± 1.2) between the reference and gated images. For images acquired during motion, all image quality measures were higher (P < 0.05) in the gated compared to nongated images (sharpness: 2.3 ± 0.4 vs. 1.8 ± 0.5, CNR: 8.5 ± 2.0 vs. 7.2 ± 2.0, score: 2.6 ± 1.2 vs. 1.8 ± 1.0). CONCLUSION Artifacts caused by the employed motion tasks deteriorated image quality in the nongated scans. These artifacts were alleviated with the proposed FID-navigator.
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Affiliation(s)
- Petter Dyverfeldt
- Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
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Nakamura M, Makabe T, Tezuka H, Miura T, Umemura T, Sugimori H, Sakata M. [Optimal scan parameters for a method of k-space trajectory (radial scan method) in evaluation of carotid plaque characteristics]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2013; 69:407-412. [PMID: 23609863 DOI: 10.6009/jjrt.2013_jsrt_69.4.407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The purpose of this study was to optimize scan parameters for evaluation of carotid plaque characteristics by k-space trajectory (radial scan method), using a custom-made carotid plaque phantom. The phantom was composed of simulated sternocleidomastoid muscle and four types of carotid plaque. The effect of chemical shift artifact was compared using T1 weighted images (T1WI) of the phantom obtained with and without fat suppression, and using two types of k-space trajectory (the radial scan method and the Cartesian method). The ratio of signal intensity of simulated sternocleidomastoid muscle to the signal intensity of hematoma, blood (including heparin), lard, and mayonnaise was compared among various repetition times (TR) using T1WI and T2 weighted imaging (T2WI). In terms of chemical shift artifacts, image quality was improved using fat suppression for both the radial scan and Cartesian methods. In terms of signal ratio, the highest values were obtained for the radial scan method with TR of 500 ms for T1WI, and TR of 3000 ms for T2WI. For evaluation of carotid plaque characteristics using the radial scan method, chemical shift artifacts were reduced with fat suppression. Signal ratio was improved by optimizing the TR settings for T1WI and T2WI. These results suggest the potential for using magnetic resonance imaging for detailed evaluation of carotid plaque.
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Narumi S, Sasaki M, Ohba H, Ogasawara K, Kobayashi M, Hitomi J, Mori K, Ohura K, Yamaguchi M, Kudo K, Terayama Y. Prediction of carotid plaque characteristics using non-gated MR imaging: correlation with endarterectomy specimens. AJNR Am J Neuroradiol 2012; 34:191-7. [PMID: 22837309 DOI: 10.3174/ajnr.a3249] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND AND PURPOSE Electrocardiographic gating, commonly used in MR carotid plaque imaging, can negatively affect intraplaque contrast if the TR is inappropriate. The present study aimed to determine whether a non-gated technique with appropriate TRs can accurately evaluate intraplaque characteristics in specimens excised by CEA. MATERIALS AND METHODS We prospectively examined 40 consecutive patients who underwent CEA (59-82 years of age) by using a 1.5T scanner. Axial T1WI with a TR of 500 ms and PDWI and T2WI with a TR of 3000 ms with a self-navigated rotating-blade scan instead of cardiac gating were obtained. Signal intensities of the plaque and adjacent muscle were measured, and the CR on T1WI, PDWI, and T2WI as well as the gray-scale median on US were correlated with the pathologic findings of the CEA specimens. RESULTS On T1WI, the CRs of the carotid plaques differed significantly among groups in which the main components were histologically confirmed as fibrous tissue, lipid/necrosis, and hemorrhage (0.54-1.17, 1.16-1.53, and 1.40-2.29, respectively). The sensitivity and specificity for discriminating lipid/necrosis/hemorrhage from fibrous tissue were 96% and 100%, respectively. On T2WI, the CRs of plaques with lipid/necrosis were significantly higher than those of other groups, but the CRs on PDWI and the gray-scale median on US were not significantly different among the groups. CONCLUSIONS Non-gated MR plaque imaging, particularly T1WI, can readily predict the intraplaque main components of the carotid artery with high sensitivity and specificity.
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Affiliation(s)
- S Narumi
- Department of Neurology and Gerontology, Iwate Medical University, Morioka, Japan.
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Makhijani MK, Balu N, Yamada K, Yuan C, Nayak KS. Accelerated 3D MERGE carotid imaging using compressed sensing with a hidden Markov tree model. J Magn Reson Imaging 2012; 36:1194-202. [PMID: 22826159 DOI: 10.1002/jmri.23755] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 06/13/2012] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To determine the potential for accelerated 3D carotid magnetic resonance imaging (MRI) using wavelet based compressed sensing (CS) with a hidden Markov tree (HMT) model. MATERIALS AND METHODS We retrospectively applied HMT model-based CS and conventional CS to 3D carotid MRI data with 0.7 mm isotropic resolution from six subjects with known carotid stenosis (12 carotids). We applied a wavelet-tree model learned from a training database of carotid images to improve CS reconstruction. Quantitative endpoints such as lumen area, wall area, mean and maximum wall thickness, plaque calcification, and necrotic core area were measured and compared using Bland-Altman analysis along with image quality. RESULTS Rate-4.5 acceleration with HMT model-based CS provided image quality comparable to that of rate-3 acceleration with conventional CS and fully sampled reference reconstructions. Morphological measurements made on rate-4.5 HMT model-based CS reconstructions were in good agreement with measurements made on fully sampled reference images. There was no significant bias or correlation between mean and difference of measurements when comparing rate 4.5 HMT model-based CS with fully sampled reference images. CONCLUSION HMT model-based CS can potentially be used to accelerate clinical carotid MRI by a factor of 4.5 without impacting diagnostic quality or quantitative endpoints.
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Affiliation(s)
- Mahender K Makhijani
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089-2564, USA.
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Abstract
The association between gadolinium-based contrast agents and neprogenic systemic fibrosis has helped propel noncontrast angiography techniques to center stage in the MR evaluation of vascular disease, especially in individuals with intrinsic renal diseases. Although balanced steady-state free precession, phase contrast, and time-of-flight sequences are currently being revisited and improved, new noncontrast angiographic methods have been created and are under development: ECG-gated 3D partial-Fourier fast spin echo (FSE) and 3D variable flip angle FSE (SPACE). All of these are attempts to develop noncontrast methods that offer equal or superior vascular diagnosis as compared with contrast-enhanced MR angiography.
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Hey S, Cernicanu A, de Senneville BD, Roujol S, Ries M, Jaïs P, Moonen CTW, Quesson B. Towards optimized MR thermometry of the human heart at 3T. NMR IN BIOMEDICINE 2012; 25:35-43. [PMID: 21732459 DOI: 10.1002/nbm.1709] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 12/14/2010] [Accepted: 02/15/2011] [Indexed: 05/31/2023]
Abstract
Catheter ablation using radio frequency (RF) has been used increasingly for the treatment of cardiac arrhythmias and may be combined with proton resonance frequency shift (PRFS) -based MR thermometry to determine the therapy endpoint. We evaluated the suitability of two different MR thermometry sequences (TFE and TFE-EPI) and three blood suppression techniques. Experiments were performed without heating, using an optimized imaging protocol including navigator respiratory compensation, cardiac triggering, and image processing for the compensation of motion and susceptibility artefacts. Blood suppression performance and its effect on temperature stability were evaluated in the ventricular septum of eight healthy volunteers using multislice double inversion recovery (MDIR), motion sensitized driven equilibrium (MSDE), and inflow saturation by saturation slabs (IS). It was shown that blood suppression during MR thermometry improves the contrast-to-noise ratio (CNR), the robustness of the applied motion correction algorithm as well as the temperature stability. A gradient echo sequence accelerated by an EPI readout and parallel imaging (SENSE) and using inflow saturation blood suppression was shown to achieve the best results. Temperature stabilities of 2 °C or better in the ventricular septum with a spatial resolution of 3.5 × 3.5 × 8mm(3) and a temporal resolution corresponding to the heart rate of the volunteer, were observed. Our results indicate that blood suppression improves the temperature stability when performing cardiac MR thermometry. The proposed MR thermometry protocol, which optimizes temperature stability in the ventricular septum, represents a step towards PRFS-based MR thermometry of the heart at 3 T.
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Affiliation(s)
- S Hey
- Laboratory for Molecular and Functional Imaging, Bordeaux, France. ‐bordeaux2.fr
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Takehara Y, Yamashita S, Sakahara H, Masui T, Isoda H. Magnetic resonance angiography of the aorta. Ann Vasc Dis 2011; 4:271-85. [PMID: 23555465 DOI: 10.3400/avd.di.11.00822] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 08/22/2011] [Indexed: 11/13/2022] Open
Abstract
Magnetic resonance angiography (MRA) is capable of imaging arteries in the half to whole body by a single acquisition without a nephrotoxic contrast medium, and acquired images can be reconstructed into a specific cross-sectional view in an arbitrary directions. MRA is applicable for vessels non-reachable by a catheter approach, and collateral vessels can be fully visualized. Since MRA is minimally-invasive with no exposure to ionized radiation, it can be repeatedly applied for follow-up. However, there are also disadvantages: the temporal and spatial resolutions are inferior to those of X-ray angiography, and, at present, it cannot be used as a guide for intervention. Moreover, gadolinium administrations may cause NSF in patients who have lost renal function, as a new risk. Accordingly, strict consideration is required for an indication of its application. Development of non-contrast MRA and evaluation of the wall itself may draw more attention in the future. Plaque imaging is being routinely performed nowadays, and the measurement of vascular wall shear stress, which has a close association with arteriosclerosis, may become possible by utilizing the time-resolved phase-contrast method capable of measuring the time-resolved velocity vectors of blood flow throughout the body. (*English Translation of J Jpn Coll Angiol, 2009, 49: 503-516.).
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Affiliation(s)
- Yasuo Takehara
- Radiology, Hamamatsu University Hospital, Hamamatsu, Shizuoka, Japan
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20
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Black blood MRI has diagnostic and prognostic value in the assessment of patients with pulmonary hypertension. Eur Radiol 2011; 22:695-702. [DOI: 10.1007/s00330-011-2306-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 09/03/2011] [Accepted: 09/28/2011] [Indexed: 02/06/2023]
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Morita S, Masukawa A, Suzuki K, Hirata M, Kojima S, Ueno E. Unenhanced MR Angiography: Techniques and Clinical Applications in Patients with Chronic Kidney Disease. Radiographics 2011; 31:E13-33. [DOI: 10.1148/rg.312105075] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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22
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Gho SM, Nam Y, Zho SY, Kim EY, Kim DH. Three dimension double inversion recovery gray matter imaging using compressed sensing. Magn Reson Imaging 2010; 28:1395-402. [PMID: 20869829 DOI: 10.1016/j.mri.2010.06.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 05/24/2010] [Accepted: 06/25/2010] [Indexed: 10/19/2022]
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Balu N, Yarnykh VL, Chu B, Wang J, Hatsukami T, Yuan C. Carotid plaque assessment using fast 3D isotropic resolution black-blood MRI. Magn Reson Med 2010; 65:627-37. [PMID: 20941742 DOI: 10.1002/mrm.22642] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 07/30/2010] [Accepted: 08/26/2010] [Indexed: 11/10/2022]
Abstract
Black-blood MRI is a promising tool for carotid atherosclerotic plaque burden assessment and compositional analysis. However, current sequences are limited by large slice thickness. Accuracy of measurement can be improved by moving to isotropic imaging but can be challenging for patient compliance due to long scan times. We present a fast isotropic high spatial resolution (0.7×0.7×0.7 mm3) three-dimensional black-blood sequence (3D-MERGE) covering the entire cervical carotid arteries within 2 min thus ensuring patient compliance and diagnostic image quality. The sequence is optimized for vessel wall imaging of the carotid bifurcation based on its signal properties. The optimized sequence is validated on patients with significant carotid plaque. Quantitative plaque morphology measurements and signal-to-noise ratio measures show that 3D-MERGE provides good blood suppression and comparable plaque burden measurements to existing MRI protocols. 3D-MERGE is a promising new tool for fast and accurate plaque burden assessment in patients with atherosclerotic plaque.
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Affiliation(s)
- Niranjan Balu
- Department of Radiology, University of Washington, Seattle, Washington 98019, USA.
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Wang J, Yarnykh VL, Yuan C. Enhanced image quality in black-blood MRI using the improved motion-sensitized driven-equilibrium (iMSDE) sequence. J Magn Reson Imaging 2010; 31:1256-63. [PMID: 20432365 DOI: 10.1002/jmri.22149] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To propose an improved motion-sensitized driven-equilibrium (iMSDE) pulse sequence to enhance the tissue signal-to-noise ratio (SNR) while maintaining the same flow suppression capability in black-blood carotid artery magnetic resonance imaging (MRI). MATERIALS AND METHODS Compared to the traditional MSDE sequence, the iMSDE sequence uses an extra refocusing pulse and two extra gradients to achieve SNR improvement. Computer simulation and phantom studies were used to evaluate both eddy currents and local B(1) inhomogeneity effects on SNR behaviors on both MSDE and iMSDE images. To further assess the SNR improvements brought by iMSDE in vivo, five healthy volunteers were also scanned with both sequences. The paired t-test was used for statistical comparison. RESULTS Both simulations and phantom studies demonstrated that eddy currents and local B(1) inhomogeneity will cause image SNR reduction in the MSDE sequence, and that these factors can be partially compensated for with the iMSDE sequence. In vivo comparison showed that the iMSDE sequence significantly improved the tissue-lumen contrast-to-noise ratio (CNR) and static tissue SNR (P < 0.001 for both), while maintaining low lumen SNR in carotid MRI. CONCLUSION Compared to the traditional MSDE sequence, the iMSDE sequence can achieve improved soft-tissue SNR and CNR in carotid artery MRI without sacrificing flow suppression capability and time efficiency.
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Affiliation(s)
- Jinnan Wang
- Department of Radiology, University of Washington, Seattle, Washington, USA.
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Fan Z, Zhang Z, Chung YC, Weale P, Zuehlsdorff S, Carr J, Li D. Carotid arterial wall MRI at 3T using 3D variable-flip-angle turbo spin-echo (TSE) with flow-sensitive dephasing (FSD). J Magn Reson Imaging 2010; 31:645-54. [PMID: 20187208 DOI: 10.1002/jmri.22058] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To evaluate the effectiveness of flow-sensitive dephasing (FSD) magnetization preparation in improving blood signal suppression of three-dimensional (3D) turbo spin-echo (TSE) sequence (SPACE) for isotropic high-spatial-resolution carotid arterial wall imaging at 3T. MATERIALS AND METHODS The FSD-prepared SPACE sequence (FSD-SPACE) was implemented by adding two identical FSD gradient pulses right before and after the first refocusing 180 degrees -pulse of the SPACE sequence in all three orthogonal directions. Nine healthy volunteers were imaged at 3T with SPACE, FSD-SPACE, and multislice T2-weighted 2D TSE coupled with saturation band (SB-TSE). Apparent carotid wall-lumen contrast-to-noise ratio (aCNR(w-l)) and apparent lumen area (aLA) at the locations with residual-blood (rb) signal shown on SPACE images were compared between SPACE and FSD-SPACE. Carotid aCNR(w-l) and lumen (LA) and wall area (WA) measured from FSD-SPACE were compared to those measured from SB-TSE. RESULTS Plaque-mimicking flow artifacts identified in seven carotids on SPACE images were eliminated on FSD-SPACE images. The FSD preparation resulted in slightly reduced aCNR(w-l) (P = 0.025), but significantly improved aCNR between the wall and rb regions (P < 0.001) and larger aLA (P < 0.001). Compared to SB-TSE, FSD-SPACE offered comparable aCNR(w-l) with much higher spatial resolution, shorter imaging time, and larger artery coverage. The LA and WA measurements from the two techniques were in good agreement based on intraclasss correlation coefficient (0.988 and 0.949, respectively; P < 0.001) and Bland-Altman analyses. CONCLUSION FSD-SPACE is a time-efficient 3D imaging technique for carotid arterial wall with superior spatial resolution and blood signal suppression.
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Affiliation(s)
- Zhaoyang Fan
- Department of Radiology, Northwestern University, Chicago, Illinois 60611, USA
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Mihai G, Chung YC, Merchant A, Simonetti OP, Rajagopalan S. T1-weighted-SPACE dark blood whole body magnetic resonance angiography (DB-WBMRA): initial experience. J Magn Reson Imaging 2010; 31:502-9. [PMID: 20099365 DOI: 10.1002/jmri.22049] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
PURPOSE To evaluate the feasibility of the dark blood fast spin echo (FSE) T1-weighted-Sampling Perfection with Application of optimized Contrasts using different flip angle Evolution (T1w-SPACE) sequence in assessing whole body arterial wall information from the extracranial carotids to the popliteal artery. MATERIALS AND METHODS Twenty-eight subjects were subjected to noncontrast, dark blood whole body magnetic resonance angiography (DB-WBMRA) using a T1w-SPACE sequence optimized for each of the individual stations: carotid artery, thoracic aorta, abdominal aorta, and thigh/superficial femoral artery (SFA). Image quality/vessel wall visualization and the time required to image the four stations were evaluated. Two observers checked the reproducibility of vessel wall depiction by performing quantitative measurements in registered initial and repeat studies (six subjects) of vessel wall and lumen area at 17 locations along the arterial tree. RESULTS In 25 of the 28 scanned subjects, dark blood arterial images acquired in approximately 1 hour total imaging time allowed whole body arterial vessel wall visualization. Quantitative measurements showed high correlation between the initial and repeat studies for each of the observers as well as high interobserver reproducibility (r > 0.95; P < 0.01). CONCLUSION DB-WBMRA using T1w-SPACE is feasible and can be performed with a high degree of reliability.
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Affiliation(s)
- Georgeta Mihai
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio, USA.
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Makhijani MK, Hu HH, Pohost GM, Nayak KS. Improved blood suppression in three-dimensional (3D) fast spin-echo (FSE) vessel wall imaging using a combination of double inversion-recovery (DIR) and diffusion sensitizing gradient (DSG) preparations. J Magn Reson Imaging 2010; 31:398-405. [PMID: 20099353 DOI: 10.1002/jmri.22042] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To provide improved blood suppression in three-dimensional inner-volume fast spin-echo (3D IV-FSE) carotid vessel wall imaging by using a hybrid preparation consisting of double inversion-recovery (DIR) and diffusion sensitizing gradients (DSG). MATERIALS AND METHODS Multicontrast black-blood MRI is widely used for vessel wall imaging and characterization of atherosclerotic plaque composition. Blood suppression is difficult when using 3D volumetric imaging techniques. DIR approaches do not provide robust blood suppression due to incomplete replacement of blood spins, and DSG approaches compromise vessel wall signal, reducing the lumen-wall contrast-to-noise ratio efficiency (CNR(eff)). In this work a hybrid DIR+DSG preparation is developed and optimized for blood suppression, vessel wall signal preservation, and vessel-wall contrast in 3D IV-FSE imaging. Cardiac gated T(1)-weighted carotid vessel wall images were acquired in five volunteers with 0.5 x 0.5 x 2.5 mm(3) spatial resolution in 80 seconds. RESULTS Data from healthy volunteers indicate that the proposed method yields a statistically significant (P < 0.01) improvement in blood suppression and lumen-wall CNR(eff) compared to standard DIR and standard DSG methods alone. CONCLUSION A combination of DIR and DSG preparations can provide improved blood suppression and lumen-wall CNR(eff) for 3D IV-FSE vessel wall imaging.
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Affiliation(s)
- Mahender K Makhijani
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA, USA.
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28
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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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29
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Narumi S, Sasaki M, Ohba H, Ogasawara K, Hitomi J, Mori K, Ohura K, Ono A, Terayama Y. Altered carotid plaque signal among different repetition times on T1-weighted magnetic resonance plaque imaging with self-navigated radial-scan technique. Neuroradiology 2009; 52:285-90. [DOI: 10.1007/s00234-009-0642-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 11/25/2009] [Indexed: 11/29/2022]
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Abstract
OBJECTIVES To evaluate the potential use of a novel 3D turbo spin-echo (TSE) T2-weighted (T2w) technique for assessing the vessel wall in the superficial femoral artery at 3.0 T. BACKGROUND Magnetic resonance imaging can be used for the noninvasive assessment of atherosclerotic plaque burden in the peripheral circulation. Although black-blood 2D TSE techniques have been used for femoral arterial wall imaging, these techniques require prolonged imaging time to cover a large field of view required to cover the leg. Recently, variable-flip-angle 3D TSE T2w (SPACE) has been introduced as a fast vessel wall imaging technique with submillimeter spatial resolution. A systematic investigation of the application of this technique to femoral arterial wall imaging has yet to be performed. METHODS Fifteen healthy volunteers and 3 patients with peripheral arterial disease (PAD) underwent 3D SPACE imaging of the superficial femoral artery at 3.0 T, with the conventional 2D TSE T2w imaging as a reference. Muscle-lumen contrast to noise ratio (CNR) and wall/lumen volumes (WV, LV) were measured at the matched locations on the 3D and 2D image sets. Statistical comparison on a per-subject basis was conducted to determine the difference and agreement between 3D SPACE and the 2D TSE techniques. RESULTS The 3D SPACE data sets enabled vessel visualization from arbitrary orientation through multiplanar reformation technique. Muscle-lumen CNR was significantly higher with 3D SPACE than with the 2D TSE (3.12 +/- 0.84 vs. 2.17 +/- 0.34, P < 0.01). This trend was confirmed when CNR efficiency (CNR(eff)) values were further compared. A similar trend was observed in PAD patients (SPACE vs. 2D TSE T2w: CNR 2.35 +/- 0.13 vs. 1.77 +/- 0.25; CNR(eff) 15.35 +/- 0.61 vs. 3.59 +/- 2.62. all P < 0.05). Measurements of WV and LV from the 3D and 2D techniques were highly correlated in volunteers and PAD patients (volunteers, WV: linear regression r2 = 0.98, LV: r2 = 0.98, P < 0.001 for both; patients, WV: linear regression r2 = 0.96, LV: r2 = 0.94, P < 0.001 for both). CONCLUSION We established the feasibility of using the 3D SPACE technique for vessel wall imaging in the superficial femoral artery at 3.0T. High, isotropic-resolution SPACE images, with the aid of multiplanar reformation, enable superior vessel wall visualization. Superior blood signal suppression comparable to vessel wall morphologic measurements, and superior time efficiency compared to conventional 2D TSE imaging indicate the great potential of the SPACE method as a noninvasive imaging technique for the assessment of atherosclerotic plaque burden in PAD patients.
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Park JK, Lee CS, Sim KB, Huh JS, Park JC. Imaging of the walls of saccular cerebral aneurysms with double inversion recovery black-blood sequence. J Magn Reson Imaging 2009; 30:1179-83. [DOI: 10.1002/jmri.21942] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Mihai G, Chung YC, Kariisa M, Raman SV, Simonetti OP, Rajagopalan S. Initial feasibility of a multi-station high resolution three-dimensional dark blood angiography protocol for the assessment of peripheral arterial disease. J Magn Reson Imaging 2009; 30:785-93. [DOI: 10.1002/jmri.21923] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Keenan NG, Grasso A, Locca D, Varghese A, Roughton M, Gatehouse PD, Firmin DN, Pennell DJ. Comparison of 2D and multislab 3D magnetic resonance techniques for measuring carotid wall volumes. J Magn Reson Imaging 2009; 28:1476-82. [PMID: 19025935 DOI: 10.1002/jmri.21582] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To compare a multislab three-dimensional volume-selective fast spin-echo (FSE) magnetic resonance (MR) sequence with a routine two-dimensional FSE sequence for quantification of carotid wall volume. MATERIALS AND METHODS One hundred normal subjects (50 men, mean age 44.6 years) underwent carotid vessel wall MR using 2D and 3D techniques. Carotid artery total vessel volume, lumen volume, wall volume, and wall/outer wall (W/OW) ratio were measured over 20 contiguous slices. Two- (2D) and three-dimensional (3D) results were compared. RESULTS The mean difference between 2D and 3D datasets (as a percentage of the mean absolute value) was 1.7% for vessel volume, 4.9% for lumen volume, 4.7% for wall volume, and 5.8% for W/OW ratio. There was good correlation between 2D and 3D models for total vessel volume (R(2) = 0.93, P < 0.001), lumen area (R(2) = 0.92, P < 0.001), and wall volume (R(2) = 0.77, P < 0.001). The correlation for the W/OW ratio was weaker (R(2) = 0.30; P < 0.001). The signal-to-noise ratio (SNR) for the 3D technique was 2.1-fold greater than for the 2D technique (P < 0.001). When using the 3D sequence, scan time was reduced by 63%. CONCLUSION Multislab volume selective 3D FSE carotid arterial wall imaging performs similarly to a conventional 2D technique, but with over twice the SNR and substantially reduced scan time.
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Affiliation(s)
- Niall G Keenan
- Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, London, UK
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Nguyen TD, de Rochefort L, Spincemaille P, Cham MD, Weinsaft JW, Prince MR, Wang Y. Effective motion-sensitizing magnetization preparation for black blood magnetic resonance imaging of the heart. J Magn Reson Imaging 2009; 28:1092-100. [PMID: 18972350 DOI: 10.1002/jmri.21568] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To investigate the effectiveness of flow signal suppression of a motion-sensitizing magnetization preparation (MSPREP) sequence and to optimize a 2D MSPREP steady-state free precession (SSFP) sequence for black blood imaging of the heart. MATERIALS AND METHODS Using a flow phantom, the effect of varying field of speed (FOS), b-value, voxel size, and flow pattern on the flow suppression was investigated. In seven healthy volunteers, black blood images of the heart were obtained at 1.5T with MSPREP-SSFP and double inversion recovery fast spin echo (DIR-FSE) techniques. Myocardium and blood signal-to-noise ratio (SNR) and myocardium-to-blood contrast-to-noise ratio (CNR) were measured. The optimal FOS that maximized the CNR for MSPREP-SSFP was determined. RESULTS Phantom data demonstrated that the flow suppression was induced primarily by the velocity encoding effect. In humans, FOS=10-20 cm/s was found to maximize the CNR for short-axis (SA) and four-chamber (4C) views. Compared to DIR-FSE, MSPREP-SSFP provided similar blood SNR efficiency in the SA basal and mid-views and significantly lower blood SNR efficiency in the SA apical (P=0.02) and 4C (P=0.01) views, indicating similar or better blood suppression. CONCLUSION Velocity encoding is the primary flow suppression mechanism of the MSPREP sequence and 2D MSPREP-SSFP black blood imaging of the heart is feasible in healthy subjects.
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Affiliation(s)
- Thanh D Nguyen
- Department of Radiology, Weill Medical College of Cornell University, New York, New York 10022, USA.
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Chiu B, Egger M, Spence JD, Parraga G, Fenster A. Quantification of carotid vessel wall and plaque thickness change using 3D ultrasound images. Med Phys 2008; 35:3691-710. [PMID: 18777929 DOI: 10.1118/1.2955550] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Quantitative measurements of carotid plaque burden progression or regression are important in monitoring patients and in evaluation of new treatment options. 3D ultrasound (US) has been used to monitor the progression or regression of carotid artery plaques. This paper reports on the development and application of a method used to analyze changes in carotid plaque morphology from 3D US. The technique used is evaluated using manual segmentations of the arterial wall and lumen from 3D US images acquired in two imaging sessions. To reduce the effect of segmentation variability, segmentation was performed five times each for the wall and lumen. The mean wall and lumen surfaces, computed from this set of five segmentations, were matched on a point-by-point basis, and the distance between each pair of corresponding points served as an estimate of the combined thickness of the plaque, intima, and media (vessel-wall-plus-plaque thickness or VWT). The VWT maps associated with the first and the second US images were compared and the differences of VWT were obtained at each vertex. The 3D VWT and VWT-Change maps may provide important information for evaluating the location of plaque progression in relation to the localized disturbances of flow pattern, such as oscillatory shear, and regression in response to medical treatments.
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Affiliation(s)
- Bernard Chiu
- Imaging Research Laboratories and Graduate Program in Biomedical Engineering, University of Western Ontario, London, Ontario, Canada.
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Wang J, Yarnykh VL, Hatsukami T, Chu B, Balu N, Yuan C. Improved suppression of plaque-mimicking artifacts in black-blood carotid atherosclerosis imaging using a multislice motion-sensitized driven-equilibrium (MSDE) turbo spin-echo (TSE) sequence. Magn Reson Med 2008; 58:973-81. [PMID: 17969103 DOI: 10.1002/mrm.21385] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this study, a turbo spin-echo (TSE) based motion-sensitized driven-equilibrium (MSDE) sequence was used as an alternative black-blood (BB) carotid MRI imaging scheme. The MSDE sequence was first optimized for more efficient residual blood signal suppression in the carotid bulb of healthy volunteers. Effective contrast-to-noise ratio (CNR(eff)) and residual signal-to-noise ratio (SNR) in the lumen measured from MSDE images were then compared to those measured from inflow saturation (IS) and double inversion-recovery (DIR) images. Statistically significant higher CNR(eff) and lower lumen SNR were obtained from MSDE images. To assess MSDE sequence in a clinical carotid protocol, 42 locations from six subjects with 50% to 79% carotid stenosis by duplex ultrasound were scanned with both MSDE and multislice DIR. The comparison showed that MSDE images present significantly higher CNR and lower lumen SNR compared to corresponding multislice DIR images. The vessel wall area and mean wall thickness measurements in MSDE images were slightly but significantly lower than those obtained with other blood suppression techniques. In conclusion, in vivo comparisons demonstrated that MSDE sequence can achieve better blood suppression and provide a more accurate depiction of the lumen boundaries by eliminating plaque mimicking artifacts in carotid artery (CA) imaging.
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Affiliation(s)
- Jinnan Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA.
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Koktzoglou I, Li D. Diffusion-prepared segmented steady-state free precession: Application to 3D black-blood cardiovascular magnetic resonance of the thoracic aorta and carotid artery walls. J Cardiovasc Magn Reson 2007; 9:33-42. [PMID: 17178678 DOI: 10.1080/10976640600843413] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
This work developed a three-dimensional (3D) diffusion-prepared segmented steady-steady free precession (DP-SSFP) cardiovascular magnetic resonance (CMR) sequence for black-blood (BB) thoracic aortic and carotid wall visualization. In 14 healthy volunteers, BB CMR of the thoracic aorta (n = 7) and carotid arteries (n = 7) was performed over 12 cm and 3 cm of transversal coverage, respectively, with a single 3D DP-SSFP acquisition and multiple two-dimensional (2D) slices using a T2-weighted (T2W) double inversion-recovery fast spin-echo (DIR-FSE) sequence. Arterial wall area (WA), lumen area (LA), and wall-lumen contrast-to-noise ratio (CNR) measured from the 3D DP-SSFP images were compared to those measured from the 2D T2W DIR-FSE images. Strong agreement in WA and LA between the two techniques was observed in the thoracic aorta (WA: intraclass correlation coefficient (ICC) = 0.866, LA: ICC = 0.993; p < 0.001 for both) and carotid arteries (WA: ICC = 0.939, LA: ICC = 0.991; p < 0.001 for both). Adjusted for slice thickness and number of slices, higher effective CNR per unit time (i.e., CNR efficiency) was attained with 3D DP-SSFP than 2D T2W DIR-FSE during thoracic aortic wall imaging (11.6 +/- 1.4 vs. 2.9 +/- 0.5; p < 0.001) and carotid artery wall imaging (10.1 +/- 1.9 vs. 3.1 +/- 0.5; p < 0.001). Diffusion-prepared segmented SSFP is a promising vessel wall CMR sequence that allows for 3D acquisition of thin and contiguous slices with BB image contrast.
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Affiliation(s)
- Ioannis Koktzoglou
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA.
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Koktzoglou I, Chung YC, Carroll TJ, Simonetti OP, Morasch MD, Li D. Three-dimensional Black-Blood MR Imaging of Carotid Arteries with Segmented Steady-State Free Precession: Initial Experience. Radiology 2007; 243:220-8. [PMID: 17392255 DOI: 10.1148/radiol.2431060310] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This HIPAA-compliant study had institutional review board approval. Informed consent was obtained. The purpose was to prospectively evaluate a segmented three-dimensional (3D) double inversion recovery (DIR)-prepared steady-state free precession (SSFP) magnetic resonance (MR) imaging sequence for fast high-spatial-resolution black-blood carotid arterial wall imaging. Carotid wall-lumen contrast-to-noise ratio (CNR) obtained with this sequence was compared with those obtained with two-dimensional (2D) single- and multisection black-blood fast spin-echo (SE) sequences. MR imaging of both carotid artery bifurcations over 3 cm of transverse coverage was performed in eight volunteers (seven men, one woman; age range, 26-56 years) with no known history of carotid artery disease. Adjusted for section thickness and imaging time per section, higher effective mean CNR was achieved with segmented 3D DIR-prepared SSFP than with single-section 2D DIR-prepared fast SE or multisection 2D saturation-band fast SE (P < .05). Segmented 3D DIR-prepared SSFP enables black-blood carotid arterial wall MR imaging with contiguous thin-section coverage and greater imaging speed and effective CNR than conventional 2D fast SE techniques.
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Affiliation(s)
- Ioannis Koktzoglou
- Department of Radiology, Division of Vascular Surgery, Northwestern University, Chicago, IL 60611, USA.
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Lin HY, Flask CA, Dale BM, Duerk JL. Rapid dark-blood carotid vessel-wall imaging with random bipolar gradients in a radial SSFP acquisition. J Magn Reson Imaging 2007; 25:1299-304. [PMID: 17520723 DOI: 10.1002/jmri.20821] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To investigate and evaluate a new rapid dark-blood vessel-wall imaging method using random bipolar gradients with a radial steady-state free precession (SSFP) acquisition in carotid applications. MATERIALS AND METHODS The carotid artery bifurcations of four asymptomatic volunteers (28-37 years old, mean age = 31 years) were included in this study. Dark-blood contrast was achieved through the use of random bipolar gradients applied prior to the signal acquisition of each radial projection in a balanced SSFP acquisition. The resulting phase variation for moving spins established significant destructive interference in the low-frequency region of k-space. This phase variation resulted in a net nulling of the signal from flowing spins, while the bipolar gradients had a minimal effect on the static spins. The net effect was that the regular SSFP signal amplitude (SA) in stationary tissues was preserved while dark-blood contrast was achieved for moving spins. In this implementation, application of the random bipolar gradient pulses along all three spatial directions nulled the signal from both in-plane and through-plane flow in phantom and in vivo studies. RESULTS In vivo imaging trials confirmed that dark-blood contrast can be achieved with the radial random bipolar SSFP method, thereby substantially reversing the vessel-to-lumen contrast-to-noise ratio (CNR) of a conventional rectilinear SSFP "bright-blood" acquisition from bright blood to dark blood with only a modest increase in TR (approximately 4 msec) to accommodate the additional bipolar gradients. CONCLUSION Overall, this sequence offers a simple and effective dark-blood contrast mechanism for high-SNR SSFP acquisitions in vessel wall imaging within a short acquisition time.
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Affiliation(s)
- Hung-Yu Lin
- Department of Radiology, University Hospitals of Cleveland and Case Western Reserve University, 11100 Euclid Avenue, Cleveland, OH 44195, USA
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Abstract
Atherosclerotic plaque rupture within the internal carotid artery is an important cause of transient ischemic attack (TIA) and stroke. Conventional imaging techniques such as ultrasound and angiography provide information about the structural consequences of such plaques in terms of luminal stenosis. Most clinical trials of carotid surgery and stenting and based on these imaging methods. Techniques aimed at imaging the biological 'functional' status of the plaque are now emerging. Most of these are based on the premise that inflammatory activity is an index of plaque stability. In this article we review potential imaging targets from the known molecular biological pathways of atherosclerosis. Both conventional imaging techniques and the newer methods are discussed. Recent data from position emission tomography (PET) imaging and from the use of superparamagnetic iron oxide particles with magnetic resonance (MR) imaging are shown.
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Affiliation(s)
- Liz Warburton
- Department of Clinical Neurosciences, Cambridge School of Clinical Medicine, Addenbrooke's Hospital Cambridge, Cambridge, UK.
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Yuan C, Kerwin WS, Yarnykh VL, Cai J, Saam T, Chu B, Takaya N, Ferguson MS, Underhill H, Xu D, Liu F, Hatsukami TS. MRI of atherosclerosis in clinical trials. NMR IN BIOMEDICINE 2006; 19:636-54. [PMID: 16986119 DOI: 10.1002/nbm.1065] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Magnetic resonance imaging (MRI) of the arterial wall has emerged as a viable technology for characterizing atherosclerotic lesions in vivo, especially within carotid arteries and other large vessels. This capability has facilitated the use of carotid MRI in clinical trials to evaluate therapeutic effects on atherosclerotic lesions themselves. MRI is specifically able to characterize three important aspects of the lesion: size, composition and biological activity. Lesion size, expressed as a total wall volume, may be more sensitive than maximal vessel narrowing (stenosis) as a measure of therapeutic effects, as it reflects changes along the entire length of the lesion and accounts for vessel remodeling. Lesion composition (e.g. lipid, fibrous and calcified content) may reflect therapeutic effects that do not alter lesion size or stenosis, but cause a transition from a vulnerable plaque composition to a more stable one. Biological activity, most notably inflammation, is an emerging target for imaging that is thought to destabilize plaque and which may be a systemic marker of vulnerability. The ability of MRI to characterize each of these features in carotid atherosclerotic lesions gives it the potential, under certain circumstances, to replace traditional trials involving large numbers of subjects and hard end-points--heart attacks and strokes--with smaller, shorter trials involving imaging end-points. In this review, the state of the art in MRI of atherosclerosis is presented in terms of hardware, image acquisition protocols and post-processing. Also, the results of validation studies for measuring lesion size, composition and inflammation will be summarized. Finally, the status of several clinical trials involving MRI of atherosclerosis will be reviewed.
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Affiliation(s)
- Chun Yuan
- Department of Radiology, University of Washington, Seattle, WA 98195, USA.
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Yarnykh VL, Yuan C. Simultaneous outer volume and blood suppression by quadruple inversion-recovery. Magn Reson Med 2006; 55:1083-92. [PMID: 16598725 DOI: 10.1002/mrm.20880] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A new method has been developed for reduced field-of-view (FOV) imaging with simultaneous blood suppression. This method combines suppression of signals from the outer volume and inflowing blood by using a small-FOV quadruple inversion-recovery (SFQIR) preparative pulse sequence consisting of two double-inversion pulse pairs separated by appropriate delays. Within each pair, inversion pulses are successively applied to the imaged slice and the slab orthogonal to the imaging plane with the thickness equal to the FOV size in the phase-encoding direction. Each double inversion results in the reinversion of the magnetization in the central part of the FOV, while the outer areas of the FOV and inflowing blood remain inverted. The SFQIR module was implemented for single- and multislice acquisition with a fast spin-echo readout sequence. Based on a theoretical model of the signal, the timing parameters of the sequence corresponding to the maximal suppression efficiency can be found by minimizing the variation of the normalized signal over the entire range of T1's that occur in tissues. The method was tested for black-blood imaging of the aorta and carotid arteries, and the results demonstrated its ability to eliminate motion and flow artifacts, reduce scan time, and improve spatial resolution.
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Affiliation(s)
- Vasily L Yarnykh
- Department of Radiology, University of Washington, Seattle, Washington 98195, USA.
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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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Yarnykh VL, Terashima M, Hayes CE, Shimakawa A, Takaya N, Nguyen PK, Brittain JH, McConnell MV, Yuan C. Multicontrast black-blood MRI of carotid arteries: Comparison between 1.5 and 3 tesla magnetic field strengths. J Magn Reson Imaging 2006; 23:691-8. [PMID: 16555259 DOI: 10.1002/jmri.20562] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To compare black-blood multicontrast carotid imaging at 3T and 1.5T and assess compatibility between morphological measurements of carotid arteries at 1.5T and 3T. MATERIALS AND METHODS Five healthy subjects and two atherosclerosis patients were scanned in 1.5T and 3T scanners with a similar protocol providing transverse T1-, T2-, and proton density (PD)-weighted black-blood images using a fast spin-echo sequence with single- (T1-weighted) or multislice (PD-/T2-weighted) double inversion recovery (DIR) preparation. Wall and lumen signal-to-noise ratio (SNR) and wall/lumen contrast-to-noise ratio (CNR) were compared in 44 artery cross-sections by paired t-test. Interscanner variability of the lumen area (LA), wall area (WA), and mean wall thickness (MWT) was assessed using Bland-Altman analysis. RESULTS Wall SNR and lumen/wall CNR significantly increased (P < 0.0001) at 3T with a 1.5-fold gain for T1-weighted images and a 1.7/1.8-fold gain for PD-/T2-weighted images. Lumen SNR did not differ for single-slice DIR T1-weighted images (P = 0.2), but was larger at 3T for multislice DIR PD-/T2-weighted images (P = 0.01/0.03). The LA, WA, and MWT demonstrated good agreement with no significant bias (P 0.5), a coefficient of variation (CV) of < 10%, and intraclass correlation coefficient (ICC) of > 0.95. CONCLUSION This study demonstrated significant improvement in SNR, CNR, and image quality for high- resolution black-blood imaging of carotid arteries at 3T. Morphologic measurements are compatible between 1.5T and 3T.
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Affiliation(s)
- Vasily L Yarnykh
- Department of Radiology, University of Washington, Seattle, Washington 98195, USA.
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Jones CE, Wolf RL, Detre JA, Das B, Saha PK, Wang J, Zhang Y, Song HK, Wright AC, Mohler EM, Fairman RM, Zager EL, Velazquez OC, Golden MA, Carpenter JP, Wehrli FW. Structural MRI of carotid artery atherosclerotic lesion burden and characterization of hemispheric cerebral blood flow before and after carotid endarterectomy. NMR IN BIOMEDICINE 2006; 19:198-208. [PMID: 16475206 DOI: 10.1002/nbm.1017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Collateral circulation plays a major role in maintaining cerebral blood flow (CBF) in patients with internal carotid artery (ICA) stenosis. CBF can remain normal despite severe ICA stenosis, making the benefit of carotid endarterectomy (CEA) or stenting difficult to assess. Before and after surgery, we assessed CBF supplied through the ipsilateral (stenotic) or contralateral ICA individually with a novel hemisphere-selective arterial spin-labeling (ASL) perfusion MR technique. We further explored the relationship between CBF and ICA obstruction ratio (OR) acquired with a multislice black-blood imaging sequence. For patients with unilateral ICA stenosis (n = 19), conventional bilateral labeling did not reveal interhemispheric differences. With unilateral labeling, CBF in the middle cerebral artery (MCA) territory on the surgical side from the ipsilateral supply (53.7 +/- 3.3 ml/100 g/min) was lower than CBF in the contralateral MCA territory from the contralateral supply (58.5 +/- 2.7 ml/100 g/min), although not statistically significant (p = 0.09). The ipsilateral MCA territory received significant (p = 0.02) contralateral supply (7.0 +/- 2.7 ml/100 g/min), while ipsilateral supply to the contralateral side was not reciprocated. After surgery (n = 11), ipsilateral supply to the MCA territory increased from 57.3 +/- 5.7 to 67.3 +/- 5.4 ml/100 g/min (p = 0.03), and contralateral supply to the ipsilateral MCA territory decreased. The best predictor of increased CBF on the side of surgery was normalized presurgical ipsilateral supply (r(2) = 0.62, p = 0.004). OR was less predictive of change, although the change in normalized contralateral supply was negatively correlated with OR(excess) (=OR(ipsilateral) - OR(contralateral)) (r(2) = 0.58, p = 0.006). The results demonstrate the effect of carotid artery stenosis on blood supply to the cerebral hemispheres, as well as the relative role of collateral pathways before surgery and redistribution of blood flow through these pathways after surgery. Unilateral ASL may better predict hemodynamic surgical outcome (measured by improved perfusion) than ICA OR.
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Affiliation(s)
- C E Jones
- Department of Radiology, Neuroradiology Section, University of Pennsylvania Medical Center, Philadelphia, 19104, USA
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Mani V, Itskovich VV, Aguiar SH, Mizsei G, Aguinaldo JGS, Samber DD, Macaluso FM, Fayad ZA. Comparison of gated and non-gated fast multislice black-blood carotid imaging using rapid extended coverage and inflow/outflow saturation techniques. J Magn Reson Imaging 2006; 22:628-33. [PMID: 16215965 DOI: 10.1002/jmri.20428] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
PURPOSE To comparatively analyze two fast in vivo multislice black-blood carotid artery vessel wall imaging techniques with and without cardiac gating. MATERIALS AND METHODS Eight subjects with carotid artery atherosclerosis, and four healthy subjects were studied using two black-blood multislice techniques: rapid extended coverage double inversion recovery (REX-DIR), and inflow/outflow saturation band (IOSB) rapid acquisition with relaxation enhancement (RARE) multislice acquisitions. Quantitative, qualitative, and morphometric analyses were performed on images. RESULTS Gating produced significantly lower values for the REX-DIR sequence with respect to signal intensity in muscle and the carotid artery wall, whereas it had no effect on flow suppression compared to non-gated images. For the IOSB sequences, gating had no significant effect on signal intensity of muscle and the carotid artery wall, but worsened flow suppression. REX-DIR and IOSB sequences were statistically different with respect to signal intensity of muscle (with REX-DIR sequences having lower values), while no statistical significance was observed for flow suppression and wall delineation. A morphologic analysis of the vessel wall and lumen comparing REX-DIR gated, IOSB gated, REX-DIR non-gated, and IOSB non-gated sequences revealed no significant differences between the acquisition techniques tested. CONCLUSION Non-gated sequences may be used instead of gated sequences in atherosclerotic vessel wall imaging without compromising image quality. This may shorten examination time and improve patient comfort.
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Affiliation(s)
- Venkatesh Mani
- Imaging Science Laboratories, Mount Sinai School of Medicine, New York, New York 10029-6574, USA
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Sørensen TS, Beerbaum P, Körperich H, Pedersen EM. Three-dimensional, isotropic MRI: a unified approach to quantification and visualization in congenital heart disease. Int J Cardiovasc Imaging 2006; 21:283-92. [PMID: 16015442 DOI: 10.1007/s10554-004-4018-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2004] [Accepted: 09/27/2004] [Indexed: 11/25/2022]
Abstract
PURPOSE Current standards in magnetic resonance imaging of congenital heart disease are based mostly on anisotropic protocols to image both morphology and function. Operator-dependent acquisition planning is typically needed to obtain the desired images. We propose to instead use operator-independent, three-dimensional, isotropic imaging protocols to acquire both morphology and function (cine and flow) of the entire heart in a few standardized acquisitions. Subsequently, due to the isotropic property of the data, any desired imaging plane can be "imaged" offline by interactive planar reformatting and used for qualitative and quantitative diagnostic evaluation. MATERIALS AND METHODS Morphological data was acquired in patients using 3D steady state free precession (SSFP) protocols, and functional data in volunteers using multislice 2D or 3D cine SSFP as well as 3D, three-component phase-contrast velocity mapping with EPI readouts. Tools to integrate morphological and functional offline image evaluation based on interactive planar reformatting, volume rendering, and corresponding quantification tools were implemented and discussed. RESULTS We successfully acquired and integrated morphology and flow and demonstrated potential clinical applications. CONCLUSION User independent acquisitions of morphological and functional isotropic 3D datasets with real-time, interactive planar reformatting, volume rendering, and integration of morphology and function, have the potential to replace conventional, user dependent, anisotropic 2D imaging in patients with cardiac malformations.
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Affiliation(s)
- Thomas Sangild Sørensen
- Center for Advanced Visualization and Interaction(CAVI), University of Aarhus, Aarhus, Denmark.
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Crowe LA, Varghese A, Mohiaddin RH, Yang GZ, Firmin DN. Elimination of residual blood flow-related signal in 3D volume-selective TSE arterial wall imaging using velocity-sensitive phase reconstruction. J Magn Reson Imaging 2006; 23:416-21. [PMID: 16456824 DOI: 10.1002/jmri.20513] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To improve 3D volume-selective turbo spin-echo (TSE) arterial wall imaging by introducing velocity phase sensitivity to the sequence. MATERIALS AND METHODS Slow or recirculating blood may give incomplete nulling in 3D vessel wall imaging, hindering differentiation between arterial wall and lumen. Reconstructed phase images are used to reduce the residual blood signal with postprocessing. A volume-selective 3D TSE (1) sequence with increased velocity sensitivity perpendicular to the slab was developed. Sensitivity was introduced by modifying the gradient waveforms such that residual signal from slow or recirculating blood is distinguished from the wall by the phase shift introduced. This was tested on a pulsatile flow phantom and the carotid artery wall of six healthy volunteers and 17 patients. Images were acquired on a Siemens Magnetom Sonata 1.5T scanner. A quantitative comparison of the lumen/wall contrast was made using images acquired with and without modification. RESULTS Velocity sensitivity produces significantly reduced residual signal by intravoxel dephasing. Phantom "lumen/tissue" contrast improved by 0.10 (P < 0.01), with a similar change in vivo (0.69-0.73, P < 0.01). Postprocessing removal of the blood signal using phase signal provided further improvement. CONCLUSION Introducing velocity sensitivity reduces unwanted, potentially misleading residual blood in 3D volume-selective vessel wall imaging.
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Affiliation(s)
- Lindsey A Crowe
- Magnetic Resonance Unit, Imperial College and Royal Brompton Hospital, Royal Brompton and Harefield NHS Trust, Sydney Street, London SW3 6NP, UK
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49
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Kholmovski EG, Parker DL. Application of phase consistency to improve time efficiency and image quality in dual echo black-blood carotid angiography. Magn Reson Imaging 2005; 23:711-22. [PMID: 16198826 DOI: 10.1016/j.mri.2005.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Accepted: 05/23/2005] [Indexed: 11/29/2022]
Abstract
There is a considerable similarity between proton density-weighted (PDw) and T2-weighted (T2w) images acquired by dual echo fast spin-echo (FSE) sequences. The similarity manifests itself not only in image space as correspondence between intensities of PDw and T2w images, but also in phase space as consistency between phases of PDw and T2w images. Methods for improving the imaging efficiency and image quality of dual echo FSE sequences based on this feature have been developed. The total scan time of dual echo FSE acquisition may be reduced by as much as 25% by incorporating an estimate of the image phase from a fully sampled PDw image when reconstructing partially sampled T2w images. The quality of T2w images acquired using phased array coils may be significantly improved by using the developed noise reduction reconstruction scheme, which is based on the correspondence between the PDw and T2w image intensities and the consistency between the PDw and T2w image phases. Studies of phantom and human subject MRI data were performed to evaluate the effectiveness of the techniques.
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Affiliation(s)
- Eugene G Kholmovski
- Department of Radiology, Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT 84132, USA.
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Sharma R, Kline RP, Wu EX, Katz JK. Rapid in vivo Taxotere quantitative chemosensitivity response by 4.23 Tesla sodium MRI and histo-immunostaining features in N-Methyl-N-Nitrosourea induced breast tumors in rats. Cancer Cell Int 2005; 5:26. [PMID: 16078994 PMCID: PMC1208921 DOI: 10.1186/1475-2867-5-26] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2004] [Accepted: 08/03/2005] [Indexed: 11/10/2022] Open
Abstract
Background Sodium weighted images can indicate sodium signal intensities from different features in the tumor before and 24 hours following administration of Taxotere. Aim To evaluate the association of in vivo intracellular sodium magnetic resonance image intensities with immuno-biomarkers and histopathological features to monitor the early tumor response to Taxotere chemotherapy in Methyl-Nitroso-Urea induced rat xenograft breast tumors. Methods and Materials Methyl-Nitroso-Urea (MNU) induced rat xenograft breast tumors were imaged for sodium MRI and compared with tumor histology, immunostaining after 24 hours chemotherapy. Results Sodium MRI signal intensities represented sodium concentrations. Excised tumor histological sections showed different in vitro histological end points i.e. single strand DNA content of cell nuclei during cell cycle (G1/S-G2/M), distinct S or M histograms (Feulgen labeling to nuclear DNA content by CAS 200), mitotic figures and apoptosis at different locations of breast tumors. Necrosis and cystic fluid appeared gray on intracellular (IC) sodium images while apoptosis rich regions appeared brighter on IC sodium images. After 24 hours Taxotere-treated tumors showed lower 'IC/EC ratio' of viable cells (65–76%) with higher mitotic index; apoptotic tumor cells at high risk due to cytotoxicity (>70% with high apoptotic index); reduced proliferation index (270 vs 120 per high power field) associated with enhanced IC sodium in vivo MR image intensities and decreased tumor size (3%; p < 0.001; n = 16) than that of pre-treated tumors. IC-Na MR signal intensities possibly indicated Taxotere chemosensitivity response in vivo associated with apoptosis and different pre-malignant features within 24 hours of exposure of cancer cells to anti-neoplastic Taxotere drug. Conclusion Sodium MRI imaging may be used as in vivo rapid drug monitoring method to evaluate Taxotere chemosensitivity response associated with neoplasia, apoptosis and tumor histology features.
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Affiliation(s)
- Rakesh Sharma
- Department of Medicine, W168th Street, Columbia University, New York, NY 10032 USA
| | - Richard P Kline
- Department of Medicine, W168th Street, Columbia University, New York, NY 10032 USA
| | - Ed X Wu
- Department of Radiology, W168th Street, Columbia University, New York, NY 10032 USA
| | - Jose K Katz
- Department of Medicine, W168th Street, Columbia University, New York, NY 10032 USA
- Department of Radiology, W168th Street, Columbia University, New York, NY 10032 USA
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