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Meng Y, Mo Z, Hao J, Peng Y, Yan H, Mu J, Ma D, Zhang X, Li Y. High-resolution intravascular magnetic resonance imaging of the coronary artery wall at 3.0 Tesla: toward evaluation of atherosclerotic plaque vulnerability. Quant Imaging Med Surg 2021; 11:4522-4529. [PMID: 34737920 DOI: 10.21037/qims-21-286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/05/2021] [Indexed: 11/06/2022]
Abstract
Background To validate the feasibility of generating high-resolution intravascular 3.0 Tesla (T) magnetic resonance imaging of the coronary artery wall to further plaque imaging. Methods A receive-only 0.014-inch diameter magnetic resonance imaging guidewire (MRIG) was manufactured for intravascular imaging within a phantom experiment and the coronary artery wall of the swine. For coronary artery wall imaging, both high-resolution images and conventional resolution images were acquired. A 16-channel commercial surface coil for magnetic resonance imaging was employed for the control group. Results For the phantom experiment, the MRIG showed a higher signal-to-noise ratio than the surface coil. The peak signal-to-noise ratio of the MRIG and the surface coil-generated imaging were 213.6 and 19.8, respectively. The signal-to-noise ratio decreased rapidly as the distance from the MRIG increased. For the coronary artery wall experiment, the vessel wall imaging by the MRIG could be identified clearly, whereas the vessel wall imaging by the surface coil was blurred. The average signal-to-noise ratio of the artery wall was 21.1±5.40 by the MRIG compared to 8.4±2.19 by the surface coil, where the resolution was set at 0.2 mm × 0.2 mm × 2 mm. As expected, the high-resolution sequence clearly showed more details than the conventional resolution sequence set at 0.7 mm × 0.7 mm × 2.0 mm. Histological examination showed no evidence of mechanical injuries in the target vessel walls. Conclusions The study validated the feasibility of generating magnetic resonance imaging (MRI) at 0.2 mm × 0.2 mm × 2 mm for the coronary artery wall using a 0.014 inch MRIG.
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Affiliation(s)
- Yanfeng Meng
- Department of MRI, Taiyuan Central Hospital of Shanxi Medical University, Taiyuan, China
| | - Zhiguang Mo
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,The Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen, China
| | - Jinying Hao
- Department of MRI, Taiyuan Central Hospital of Shanxi Medical University, Taiyuan, China
| | - Yueyou Peng
- Department of MRI, Taiyuan Central Hospital of Shanxi Medical University, Taiyuan, China
| | - Hui Yan
- Department of MRI, Taiyuan Central Hospital of Shanxi Medical University, Taiyuan, China
| | - Jingbo Mu
- Department of Cardiology, Taiyuan Central Hospital of Shanxi Medical University, Taiyuan, China
| | - Dengfeng Ma
- Department of Cardiology, Taiyuan Central Hospital of Shanxi Medical University, Taiyuan, China
| | - Xiaoliang Zhang
- Department of Biomedical Engineering, State University of New York at Buffalo, NY, USA
| | - Ye Li
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,The Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen, China
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Liu X, Karmarkar P, Voit D, Frahm J, Weiss CR, Kraitchman DL, Bottomley PA. Real-Time High-Resolution MRI Endoscopy at up to 10 Frames per Second. BME FRONTIERS 2021; 2021:6185616. [PMID: 37849906 PMCID: PMC10521714 DOI: 10.34133/2021/6185616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 02/02/2021] [Indexed: 10/19/2023] Open
Abstract
Objective. Atherosclerosis is a leading cause of mortality and morbidity. Optical endoscopy, ultrasound, and X-ray offer minimally invasive imaging assessments but have limited sensitivity for characterizing disease and therapeutic response. Magnetic resonance imaging (MRI) endoscopy is a newer idea employing tiny catheter-mounted detectors connected to the MRI scanner. It can see through vessel walls and provide soft-tissue sensitivity, but its slow imaging speed limits practical applications. Our goal is high-resolution MRI endoscopy with real-time imaging speeds comparable to existing modalities. Methods. Intravascular (3 mm) transmit-receive MRI endoscopes were fabricated for highly undersampled radial-projection MRI in a clinical 3-tesla MRI scanner. Iterative nonlinear reconstruction was accelerated using graphics processor units connected via a single ethernet cable to achieve true real-time endoscopy visualization at the scanner. MRI endoscopy was performed at 6-10 frames/sec and 200-300 μm resolution in human arterial specimens and porcine vessels ex vivo and in vivo and compared with fully sampled 0.3 frames/sec and three-dimensional reference scans using mutual information (MI) and structural similarity (3-SSIM) indices. Results. High-speed MRI endoscopy at 6-10 frames/sec was consistent with fully sampled MRI endoscopy and histology, with feasibility demonstrated in vivo in a large animal model. A 20-30-fold speed-up vs. 0.3 frames/sec reference scans came at a cost of ~7% in MI and ~45% in 3-SSIM, with reduced motion sensitivity. Conclusion. High-resolution MRI endoscopy can now be performed at frame rates comparable to those of X-ray and optical endoscopy and could provide an alternative to existing modalities, with MRI's advantages of soft-tissue sensitivity and lack of ionizing radiation.
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Affiliation(s)
- Xiaoyang Liu
- Department of Electrical and Computer Engineering, Johns Hopkins University, USA
- The Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Parag Karmarkar
- The Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Dirk Voit
- Biomedizinishe NMR, Max-Plank-Institut fur Biophysikalische Chemie, Gottingen, Germany
| | - Jens Frahm
- Biomedizinishe NMR, Max-Plank-Institut fur Biophysikalische Chemie, Gottingen, Germany
| | - Clifford R. Weiss
- The Division of Interventional Radiology, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Dara L. Kraitchman
- The Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Paul A. Bottomley
- Department of Electrical and Computer Engineering, Johns Hopkins University, USA
- The Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
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3
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Liu X, Ellens N, Williams E, Burdette EC, Karmarkar P, Weiss CR, Kraitchman D, Bottomley PA. High-resolution intravascular MRI-guided perivascular ultrasound ablation. Magn Reson Med 2019; 83:240-253. [PMID: 31402512 DOI: 10.1002/mrm.27932] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/24/2019] [Accepted: 07/15/2019] [Indexed: 12/22/2022]
Abstract
PURPOSE To develop and test in animal studies ex vivo and in vivo, an intravascular (IV) MRI-guided high-intensity focused ultrasound (HIFU) ablation method for targeting perivascular pathology with minimal injury to the vessel wall. METHODS IV-MRI antennas were combined with 2- to 4-mm diameter water-cooled IV-ultrasound ablation catheters for IV-MRI on a 3T clinical MRI scanner. A software interface was developed for monitoring thermal dose with real-time MRI thermometry, and an MRI-guided ablation protocol developed by repeat testing on muscle and liver tissue ex vivo. MRI thermal dose was measured as cumulative equivalent minutes at 43°C (CEM43 ). The IV-MRI IV-HIFU protocol was then tested by targeting perivascular ablations from the inferior vena cava of 2 pigs in vivo. Thermal dose and lesions were compared by gross and histological examination. RESULTS Ex vivo experiments yielded a 6-min ablation protocol with the IV-ultrasound catheter coolant at 3-4°C, a 30 mL/min flow rate, and 7 W ablation power. In 8 experiments, 5- to 10-mm thick thermal lesions of area 0.5-2 cm2 were produced that spared 1- to 2-mm margins of tissue abutting the catheters. The radial depths, areas, and preserved margins of ablation lesions measured from gross histology were highly correlated (r ≥ 0.79) with those measured from the CEM43 = 340 necrosis threshold determined by MRI thermometry. The psoas muscle was successfully targeted in the 2 live pigs, with the resulting ablations controlled under IV-MRI guidance. CONCLUSION IV-MRI-guided, IV-HIFU has potential as a precision treatment option that could preserve critical blood vessel wall during ablation of nonresectable perivascular tumors or other pathologies.
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Affiliation(s)
- Xiaoyang Liu
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland.,Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Nicholas Ellens
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland.,Acertara Acoustic Laboratories, Longmont, Colorado
| | | | | | - Parag Karmarkar
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Clifford R Weiss
- Division of Interventional Radiology, Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Dara Kraitchman
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Paul A Bottomley
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland.,Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland
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Wang G, Zhang Y, Hegde SS, Bottomley PA. High-resolution and accelerated multi-parametric mapping with automated characterization of vessel disease using intravascular MRI. J Cardiovasc Magn Reson 2017; 19:89. [PMID: 29157260 PMCID: PMC5694914 DOI: 10.1186/s12968-017-0399-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 10/16/2017] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Atherosclerosis is prevalent in cardiovascular disease, but present imaging modalities have limited capabilities for characterizing lesion stage, progression and response to intervention. This study tests whether intravascular magnetic resonance imaging (IVMRI) measures of relaxation times (T1, T2) and proton density (PD) in a clinical 3 Tesla scanner could characterize vessel disease, and evaluates a practical strategy for accelerated quantification. METHODS IVMRI was performed in fresh human artery segments and swine vessels in vivo, using fast multi-parametric sequences, 1-2 mm diameter loopless antennae and 200-300 μm resolution. T1, T2 and PD data were used to train a machine learning classifier (support vector machine, SVM) to automatically classify normal vessel, and early or advanced disease, using histology for validation. Disease identification using the SVM was tested with receiver operating characteristic curves. To expedite acquisition of T1, T2 and PD data for vessel characterization, the linear algebraic method ('SLAM') was modified to accommodate the antenna's highly-nonuniform sensitivity, and used to provide average T1, T2 and PD measurements from compartments of normal and pathological tissue segmented from high-resolution images at acceleration factors of R ≤ 18-fold. The results were validated using compartment-average measures derived from the high-resolution scans. RESULTS The SVM accurately classified ~80% of samples into the three disease classes. The 'area-under-the-curve' was 0.96 for detecting disease in 248 samples, with T1 providing the best discrimination. SLAM T1, T2 and PD measures for R ≤ 10 were indistinguishable from the true means of segmented tissue compartments. CONCLUSION High-resolution IVMRI measures of T1, T2 and PD with a trained SVM can automatically classify normal, early and advanced atherosclerosis with high sensitivity and specificity. Replacing relaxometric MRI with SLAM yields good estimates of T1, T2 and PD an order-of-magnitude faster to facilitate IVMRI-based characterization of vessel disease.
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Affiliation(s)
- Guan Wang
- Department of Electrical & Computer Engineering, Johns Hopkins University, Baltimore, MD USA
- Division of MR Research, Department of Radiology and Radiological Sciences, Johns Hopkins University, Park building 310, 600 N Wolfe Street, Baltimore, MD 21287 USA
| | - Yi Zhang
- Division of MR Research, Department of Radiology and Radiological Sciences, Johns Hopkins University, Park building 310, 600 N Wolfe Street, Baltimore, MD 21287 USA
| | - Shashank Sathyanarayana Hegde
- Division of MR Research, Department of Radiology and Radiological Sciences, Johns Hopkins University, Park building 310, 600 N Wolfe Street, Baltimore, MD 21287 USA
| | - Paul A. Bottomley
- Department of Electrical & Computer Engineering, Johns Hopkins University, Baltimore, MD USA
- Division of MR Research, Department of Radiology and Radiological Sciences, Johns Hopkins University, Park building 310, 600 N Wolfe Street, Baltimore, MD 21287 USA
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5
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Yonetsu T, Jang IK. Advances in Intravascular Imaging: New Insights into the Vulnerable Plaque from Imaging Studies. Korean Circ J 2017; 48:1-15. [PMID: 29171202 PMCID: PMC5764866 DOI: 10.4070/kcj.2017.0182] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 09/26/2017] [Accepted: 10/09/2017] [Indexed: 11/11/2022] Open
Abstract
The term “vulnerable plaque” denotes the plaque characteristics that are susceptible to coronary thrombosis. Previous post-mortem studies proposed 3 major mechanisms of coronary thrombosis: plaque rupture, plaque erosion, and calcified nodules. Of those, characteristics of rupture-prone plaque have been extensively studied. Pathology studies have identified the features of rupture-prone plaque including thin fibrous cap, large necrotic core, expansive vessel remodeling, inflammation, and neovascularization. Intravascular imaging modalities have emerged as adjunctive tools of angiography to identify vulnerable plaques. Multiple devices have been introduced to catheterization laboratories to date, including intravascular ultrasound (IVUS), virtual-histology IVUS, optical coherence tomography (OCT), coronary angioscopy, and near-infrared spectroscopy. With the use of these modalities, our understanding of vulnerable plaque has rapidly grown over the past several decades. One of the goals of intravascular imaging is to better predict and prevent future coronary events, for which prospective observational data is still lacking. OCT delineates microstructures of plaques, whereas IVUS visualizes macroscopic vascular structures. Specifically, plaque erosion, which has been underestimated in clinical practice, is gaining an interest due to the potential of OCT to make an in vivo diagnosis. Another potential future avenue for intravascular imaging is its use to guide treatment. Feasibility of tailored therapy for acute coronary syndromes (ACS) guided by OCT is under investigation. If it is proven to be effective, it may potentially lead to major shift in the management of millions of patients with ACS every year.
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Affiliation(s)
- Taishi Yonetsu
- Department of Cardiovascular Medicine, Tsuchiura Kyodo General Hospital, Tsuchiura, Japan
| | - Ik Kyung Jang
- Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.,Division of Cardiology, Kyung-Hee University Hospital, Seoul, Korea.
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Abstract
Non-invasive external magnetic resonance imaging (MRI) of large vessel atherosclerosis is a robust and promising imaging modality that can be applied for the evaluation of the atherosclerotic process in large vessels. However, it requires expertise for setup and time for data acquisition and analysis. Intravascular MRI is a promising tool, but its use remains at the pre-clinical stage within selected research groups. In this review, the current status and future role of intravascular MRI for atherosclerotic plaque characterization are summarized, along with important challenges which will be necessary to overcome prior to the wide adoption of this technique.
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Affiliation(s)
- João L Cavalcante
- Department of Medicine, Division of Cardiology, UPMC Heart & Vascular Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Eric Larose
- Faculté de médecine, Université Laval, Quebec, Quebec, Canada.
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec - Université Laval, 2725 chemin Sainte-Foy, Quebec, Quebec, G1V 4G5, Canada.
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7
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Ertürk MA, El-Sharkawy AMM, Bottomley PA. Monitoring local heating around an interventional MRI antenna with RF radiometry. Med Phys 2016; 42:1411-23. [PMID: 25735295 DOI: 10.1118/1.4907960] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Radiofrequency (RF) radiometry uses thermal noise detected by an antenna to measure the temperature of objects independent of medical imaging technologies such as magnetic resonance imaging (MRI). Here, an active interventional MRI antenna can be deployed as a RF radiometer to measure local heating, as a possible new method of monitoring device safety and thermal therapy. METHODS A 128 MHz radiometer receiver was fabricated to measure the RF noise voltage from an interventional 3 T MRI loopless antenna and calibrated for temperature in a uniformly heated bioanalogous gel phantom. Local heating (ΔT) was induced using the antenna for RF transmission and measured by RF radiometry, fiber-optic thermal sensors, and MRI thermometry. The spatial thermal sensitivity of the antenna radiometer was numerically computed using a method-of-moment electric field analyses. The gel's thermal conductivity was measured by MRI thermometry, and the localized time-dependent ΔT distribution computed from the bioheat transfer equation and compared with radiometry measurements. A "H-factor" relating the 1 g-averaged ΔT to the radiometric temperature was introduced to estimate peak temperature rise in the antenna's sensitive region. RESULTS The loopless antenna radiometer linearly tracked temperature inside a thermally equilibrated phantom up to 73 °C to within ±0.3 °C at a 2 Hz sample rate. Computed and MRI thermometric measures of peak ΔT agreed within 13%. The peak 1 g-average temperature was H = 1.36 ± 0.02 times higher than the radiometric temperature for any media with a thermal conductivity of 0.15-0.50 (W/m)/K, indicating that the radiometer can measure peak 1 g-averaged ΔT in physiologically relevant tissue within ±0.4 °C. CONCLUSIONS Active internal MRI detectors can serve as RF radiometers at the MRI frequency to provide accurate independent measures of local and peak temperature without the artifacts that can accompany MRI thermometry or the extra space needed to accommodate alternative thermal transducers. A RF radiometer could be integrated in a MRI scanner to permit "self-monitoring" for assuring device safety and/or monitoring delivery of thermal therapy.
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Affiliation(s)
- M Arcan Ertürk
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21287 and Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University, Baltimore, Maryland 21287
| | - AbdEl-Monem M El-Sharkawy
- Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University, Baltimore, Maryland 21287
| | - Paul A Bottomley
- Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University, Baltimore, Maryland 21287
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8
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Saam T, Habs M, Buchholz M, Schindler A, Bayer-Karpinska A, Cyran CC, Yuan C, Reiser M, Helck A. Expansive arterial remodeling of the carotid arteries and its effect on atherosclerotic plaque composition and vulnerability: an in-vivo black-blood 3T CMR study in symptomatic stroke patients. J Cardiovasc Magn Reson 2016; 18:11. [PMID: 26940800 PMCID: PMC4778304 DOI: 10.1186/s12968-016-0229-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 02/10/2016] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Based on intravascular ultrasound of the coronary arteries expansive arterial remodeling is supposed to be a feature of the vulnerable atheroslerotic plaque. However, till now little is known regarding the clinical impact of expansive remodeling of carotid lesions. Therefore, we sought to evaluate the correlation of expansive arterial remodeling of the carotid arteries with atherosclerotic plaque composition and vulnerability using in-vivo Cardiovascular Magnetic Resonance (CMR). METHODS One hundred eleven symptomatic patients (74 male/71.8 ± 10.3y) with acute unilateral ischemic stroke and carotid plaques of at least 2 mm thickness were included. All patients received a dedicated multi-sequence black-blood carotid CMR (3Tesla) of the proximal internal carotid arteries (ICA). Measurements of lumen, wall, outer wall, hemorrhage, calcification and necrotic core were determined. Each vessel-segment was classified according to American Heart Association (AHA) criteria for vulnerable plaque. A modified remodeling index (mRI) was established by dividing the average outer vessel area of the ICA segments by the lumen area measured on TOF images in a not affected reference segment at the distal ipsilateral ICA. Correlations of mRI and clinical symptoms as well as plaque morphology/vessel dimensions were evaluated. RESULTS Seventy-eight percent (157/202) of all internal carotid arteries showed atherosclerotic disease with AHA Lesion-Type (LT) III or higher. The mRI of the ICA was significantly different in normal artery segments (AHA LT I; mRI 1.9) compared to atherosclerotic segments (AHA LT III-VII; mRI 2.5; p < 0.0001). Between AHA LT III-VII there was no significant difference of mRI. Significant correlations (p < 0.05) of the mRI with lumen-area (LA), wall-area (WA), vessel-area (VA) and wall-thickness (WT), necrotic-core area (NC), and ulcer-area were observed. With respect to clinical presentation (symptomatic/asymptomatic side) and luminal narrowing (stenotic/non-stenotic) no relevant correlations or significant differences regarding the mRI were found. CONCLUSION Expansive arterial remodeling exists in the ICA. However, no significant association between expansive arterial remodeling, stroke symptoms, complicated AHA VI plaque, and luminal stenosis could be established. Hence, results of our study suggest that expansive arterial remodeling is not a very practical marker for plaque vulnerability in the carotid arteries.
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Affiliation(s)
- Tobias Saam
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Marchioninistr.15, 81377, Munich, Germany.
| | - Maximilian Habs
- Department of Neurology, Ludwig-Maximilians-University Hospital, Munich, Germany.
| | - Martin Buchholz
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Marchioninistr.15, 81377, Munich, Germany.
| | - Andreas Schindler
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Marchioninistr.15, 81377, Munich, Germany.
| | - Anna Bayer-Karpinska
- Institute for Stroke and Dementia Research, Ludwig-Maximilians-University Hospital, Munich, Germany.
| | - Clemens C Cyran
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Marchioninistr.15, 81377, Munich, Germany.
| | - Chun Yuan
- Department of Radiology, University of Washington, Seattle, WA, USA.
| | - Maximilian Reiser
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Marchioninistr.15, 81377, Munich, Germany.
| | - Andreas Helck
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Marchioninistr.15, 81377, Munich, Germany.
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Pennell DJ, Baksi AJ, Kilner PJ, Mohiaddin RH, Prasad SK, Alpendurada F, Babu-Narayan SV, Neubauer S, Firmin DN. Review of Journal of Cardiovascular Magnetic Resonance 2013. J Cardiovasc Magn Reson 2014; 16:100. [PMID: 25475898 PMCID: PMC4256918 DOI: 10.1186/s12968-014-0100-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 11/21/2014] [Indexed: 01/19/2023] Open
Abstract
There were 109 articles published in the Journal of Cardiovascular Magnetic Resonance (JCMR) in 2013, which is a 21% increase on the 90 articles published in 2012. The quality of the submissions continues to increase. The editors are delighted to report that the 2012 JCMR Impact Factor (which is published in June 2013) has risen to 5.11, up from 4.44 for 2011 (as published in June 2012), a 15% increase and taking us through the 5 threshold for the first time. The 2012 impact factor means that the JCMR papers that were published in 2010 and 2011 were cited on average 5.11 times in 2012. The impact factor undergoes natural variation according to citation rates of papers in the 2 years following publication, and is significantly influenced by highly cited papers such as official reports. However, the progress of the journal's impact over the last 5 years has been impressive. Our acceptance rate is <25% and has been falling because the number of articles being submitted has been increasing. In accordance with Open-Access publishing, the JCMR articles go on-line as they are accepted with no collating of the articles into sections or special thematic issues. For this reason, the Editors have felt that it is useful once per calendar year to summarize the papers for the readership into broad areas of interest or theme, so that areas of interest can be reviewed in a single article in relation to each other and other recent JCMR articles. The papers are presented in broad themes and set in context with related literature and previously published JCMR papers to guide continuity of thought in the journal. We hope that you find the open-access system increases wider reading and citation of your papers, and that you will continue to send your quality manuscripts to JCMR for publication.
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Affiliation(s)
- Dudley John Pennell
- />Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP UK
- />Imperial College, London, UK
| | - Arun John Baksi
- />Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP UK
- />Imperial College, London, UK
| | - Philip John Kilner
- />Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP UK
- />Imperial College, London, UK
| | - Raad Hashem Mohiaddin
- />Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP UK
- />Imperial College, London, UK
| | - Sanjay Kumar Prasad
- />Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP UK
- />Imperial College, London, UK
| | - Francisco Alpendurada
- />Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP UK
- />Imperial College, London, UK
| | - Sonya Vidya Babu-Narayan
- />Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP UK
- />Imperial College, London, UK
| | | | - David Nigel Firmin
- />Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP UK
- />Imperial College, London, UK
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10
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Zhang C, Zhao L, Ma X, Zhang Z, Fan Z. A feasibility study of an intravascular imaging antenna to image atherosclerotic plaques in Swine using 3.0 T MRI. PLoS One 2014; 9:e108301. [PMID: 25259585 PMCID: PMC4178132 DOI: 10.1371/journal.pone.0108301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 08/28/2014] [Indexed: 12/04/2022] Open
Abstract
Purpose To investigate the feasibility of an intravascular imaging antenna to image abdominal aorta atherosclerotic plaque in swine using 3.0T magnetic resonance imaging (MRI). Methods Atherosclerotic model was established in 6 swine. After 8 months, swine underwent an MR examination, which was performed using an intravascular imaging guide-wire, and images of the common iliac artery and the abdominal aorta were acquired. Intravascular ultrasound (IVUS) was performed in the right femoral artery; images at the same position as for the MR examination were obtained. The luminal border and external elastic membrane of the targeted arteries were individually drawn in the MR and IVUS images. After co-registering these images, the vessel, lumen, and vessel wall areas and the plaque burden in the same lesions imaged using different modalities were calculated and compared. The diagnostic accuracy of intravascular MR examination in delineating the vessel wall and detecting plaques were analyzed and compared using IVUS. Results Compared with IVUS, good agreement was found between MRI and IVUS for delineating vessel, lumen, and vessel wall areas and plaque burden (r value: 0.98, 0.95, 0.96 and 0.91, respectively; P<0.001). Conclusion Compared with IVUS, using an intravascular imaging guide-wire to image deep seated arteries allowed determination of the vessel, lumen and vessel wall areas and plaque size and burden. This may provide an alternative method for detecting atherosclerotic plaques in the future.
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Affiliation(s)
- Chen Zhang
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Lei Zhao
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Xiaohai Ma
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
- * E-mail:
| | - Zhaoqi Zhang
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Zhanming Fan
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
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11
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Nieuwstadt HA, van der Lugt A, Kassar ZAM, Breeuwer M, van der Steen AFW, Gijsen FJH. Atherosclerotic plaque fibrous cap assessment under an oblique scan plane orientation in carotid MRI. Quant Imaging Med Surg 2014; 4:216-24. [PMID: 25202656 DOI: 10.3978/j.issn.2223-4292.2014.07.05] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 07/04/2014] [Indexed: 11/14/2022]
Abstract
Carotid magnetic resonance imaging (MRI) is used to noninvasively assess atherosclerotic plaque fibrous cap (FC) status, which is closely related to ischemic stroke. Acquiring anisotropic voxels improves in-plane visualization, however, an oblique scan plane orientation could then obscure a FC (i.e., contrast below the noise level) and thus impair a reliable status assessment. To quantify this, we performed single-slice numerical simulations of a clinical 3.0T, 2D T1-weighted, black-blood, contrast-enhanced pulse sequence with various voxel dimensions: in-plane voxel size of 0.62 mm × 0.62 mm and 0.31 mm × 0.31 mm, slice thickness of 1, 2, and 3 mm. Idealized plaque models (FC thickness of 0.5, 1, and 1.5 mm) were imaged at various scan plane angles (0°-40° in steps of 10°), and the FC contrast was quantified. We found that when imaging thin FCs with anisotropic voxels, the FC contrast decreased when the scan plane orientation angle increased. However, a reduced in-plane voxel size at the cost of an increased slice thickness often led to enhanced FC contrast even in the presence of scan plane orientation angles of up to 40°. It can be concluded that while isotropic-voxel imaging eliminates the issue of scan plane obliqueness, it comes at the cost of reduced FC contrast, thus likely decreasing the reliability of FC status assessment in carotid MRI. If scan plane orientation obliquity at the slice of interest is moderate (<40°) or otherwise diminished through careful scan planning, voxel anisotropy could increase FC contrast and, in effect, increase the reliability of FC status assessment.
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Affiliation(s)
- Harm A Nieuwstadt
- 1 Department of Biomedical Engineering, 2 Department of Radiology, Erasmus MC, Rotterdam, the Netherlands ; 3 Department of MR Clinical Science, Philips Healthcare, Best, the Netherlands ; 4 Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands ; 5 Department of Imaging Science and Technology, Delft University of Technology, Delft, the Netherlands
| | - Aad van der Lugt
- 1 Department of Biomedical Engineering, 2 Department of Radiology, Erasmus MC, Rotterdam, the Netherlands ; 3 Department of MR Clinical Science, Philips Healthcare, Best, the Netherlands ; 4 Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands ; 5 Department of Imaging Science and Technology, Delft University of Technology, Delft, the Netherlands
| | - Zaid A M Kassar
- 1 Department of Biomedical Engineering, 2 Department of Radiology, Erasmus MC, Rotterdam, the Netherlands ; 3 Department of MR Clinical Science, Philips Healthcare, Best, the Netherlands ; 4 Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands ; 5 Department of Imaging Science and Technology, Delft University of Technology, Delft, the Netherlands
| | - Marcel Breeuwer
- 1 Department of Biomedical Engineering, 2 Department of Radiology, Erasmus MC, Rotterdam, the Netherlands ; 3 Department of MR Clinical Science, Philips Healthcare, Best, the Netherlands ; 4 Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands ; 5 Department of Imaging Science and Technology, Delft University of Technology, Delft, the Netherlands
| | - Anton F W van der Steen
- 1 Department of Biomedical Engineering, 2 Department of Radiology, Erasmus MC, Rotterdam, the Netherlands ; 3 Department of MR Clinical Science, Philips Healthcare, Best, the Netherlands ; 4 Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands ; 5 Department of Imaging Science and Technology, Delft University of Technology, Delft, the Netherlands
| | - Frank J H Gijsen
- 1 Department of Biomedical Engineering, 2 Department of Radiology, Erasmus MC, Rotterdam, the Netherlands ; 3 Department of MR Clinical Science, Philips Healthcare, Best, the Netherlands ; 4 Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands ; 5 Department of Imaging Science and Technology, Delft University of Technology, Delft, the Netherlands
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Qian D, El-Sharkawy AMM, Bottomley PA, Edelstein WA. An RF dosimeter for independent SAR measurement in MRI scanners. Med Phys 2014; 40:122303. [PMID: 24320534 DOI: 10.1118/1.4829527] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The monitoring and management of radio frequency (RF) exposure is critical for ensuring magnetic resonance imaging (MRI) safety. Commercial MRI scanners can overestimate specific absorption rates (SAR) and improperly restrict clinical MRI scans or the application of new MRI sequences, while underestimation of SAR can lead to tissue heating and thermal injury. Accurate scanner-independent RF dosimetry is essential for measuring actual exposure when SAR is critical for ensuring regulatory compliance and MRI safety, for establishing RF exposure while evaluating interventional leads and devices, and for routine MRI quality assessment by medical physicists. However, at present there are no scanner-independent SAR dosimeters. METHODS An SAR dosimeter with an RF transducer comprises two orthogonal, rectangular copper loops and a spherical MRI phantom. The transducer is placed in the magnet bore and calibrated to approximate the resistive loading of the scanner's whole-body birdcage RF coil for human subjects in Philips, GE and Siemens 3 tesla (3T) MRI scanners. The transducer loop reactances are adjusted to minimize interference with the transmit RF field (B1) at the MRI frequency. Power from the RF transducer is sampled with a high dynamic range power monitor and recorded on a computer. The deposited power is calibrated and tested on eight different MRI scanners. Whole-body absorbed power vs weight and body mass index (BMI) is measured directly on 26 subjects. RESULTS A single linear calibration curve sufficed for RF dosimetry at 127.8 MHz on three different Philips and three GE 3T MRI scanners. An RF dosimeter operating at 123.2 MHz on two Siemens 3T scanners required a separate transducer and a slightly different calibration curve. Measurement accuracy was ∼3%. With the torso landmarked at the xiphoid, human adult whole-body absorbed power varied approximately linearly with patient weight and BMI. This indicates that whole-body torso SAR is on average independent of the imaging subject, albeit with fluctuations. CONCLUSIONS Our 3T RF dosimeter and transducers accurately measure RF exposure in body-equivalent loads and provide scanner-independent assessments of whole-body RF power deposition for establishing safety compliance useful for MRI sequence and device testing.
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Affiliation(s)
- Di Qian
- Division of MR Research, Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287 and Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21218
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Pennell DJ, Baksi AJ, Carpenter JP, Firmin DN, Kilner PJ, Mohiaddin RH, Prasad SK. Review of Journal of Cardiovascular Magnetic Resonance 2012. J Cardiovasc Magn Reson 2013; 15:76. [PMID: 24006874 PMCID: PMC3847143 DOI: 10.1186/1532-429x-15-76] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 08/22/2013] [Indexed: 02/07/2023] Open
Abstract
There were 90 articles published in the Journal of Cardiovascular Magnetic Resonance (JCMR) in 2012, which is an 8% increase in the number of articles since 2011. The quality of the submissions continues to increase. The editors are delighted to report that the 2011 JCMR Impact Factor (which is published in June 2012) has risen to 4.44, up from 3.72 for 2010 (as published in June 2011), a 20% increase. The 2011 impact factor means that the JCMR papers that were published in 2009 and 2010 were cited on average 4.44 times in 2011. The impact factor undergoes natural variation according to citation rates of papers in the 2 years following publication, and is significantly influenced by highly cited papers such as official reports. However, the progress of the journal's impact over the last 5 years has been impressive. Our acceptance rate is approximately 25%, and has been falling as the number of articles being submitted has been increasing. In accordance with Open-Access publishing, the JCMR articles go on-line as they are accepted with no collating of the articles into sections or special thematic issues. For this reason, the Editors have felt that it is useful once per calendar year to summarize the papers for the readership into broad areas of interest or theme, so that areas of interest can be reviewed in a single article in relation to each other and other recent JCMR articles. The papers are presented in broad themes and set in context with related literature and previously published JCMR papers to guide continuity of thought in the journal. We hope that you find the open-access system increases wider reading and citation of your papers, and that you will continue to send your quality manuscripts to JCMR for publication.
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Affiliation(s)
- Dudley J Pennell
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- Imperial College, London, UK
| | - A John Baksi
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- Imperial College, London, UK
| | - John Paul Carpenter
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- Imperial College, London, UK
| | - David N Firmin
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- Imperial College, London, UK
| | - Philip J Kilner
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- Imperial College, London, UK
| | - Raad H Mohiaddin
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- Imperial College, London, UK
| | - Sanjay K Prasad
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- Imperial College, London, UK
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Nieuwstadt HA, Geraedts TR, Truijman MTB, Kooi ME, van der Lugt A, van der Steen AFW, Wentzel JJ, Breeuwer M, Gijsen FJH. Numerical simulations of carotid MRI quantify the accuracy in measuring atherosclerotic plaque components in vivo. Magn Reson Med 2013; 72:188-201. [PMID: 23943090 DOI: 10.1002/mrm.24905] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 06/18/2013] [Accepted: 07/05/2013] [Indexed: 12/18/2022]
Abstract
PURPOSE Atherosclerotic carotid plaques can be quantified in vivo by MRI. However, the accuracy in segmentation and quantification of components such as the thin fibrous cap (FC) and lipid-rich necrotic core (LRNC) remains unknown due to the lack of a submillimeter scale ground truth. METHODS A novel approach was taken by numerically simulating in vivo carotid MRI providing a ground truth comparison. Upon evaluation of a simulated clinical protocol, MR readers segmented simulated images of cross-sectional plaque geometries derived from histological data of 12 patients. RESULTS MR readers showed high correlation (R) and intraclass correlation (ICC) in measuring the luminal area (R = 0.996, ICC = 0.99), vessel wall area (R = 0.96, ICC = 0.94) and LRNC area (R = 0.95, ICC = 0.94). LRNC area was underestimated (mean error, -24%). Minimum FC thickness showed a mediocre correlation and intraclass correlation (R = 0.71, ICC = 0.69). CONCLUSION Current clinical MRI can quantify carotid plaques but shows limitations for thin FC thickness quantification. These limitations could influence the reliability of carotid MRI for assessing plaque rupture risk associated with FC thickness. Overall, MRI simulations provide a feasible methodology for assessing segmentation and quantification accuracy, as well as for improving scan protocol design.
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Affiliation(s)
- Harm A Nieuwstadt
- Department of Biomedical Engineering, Erasmus Medical Center, Rotterdam, the Netherlands
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15
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Chan RH, Manning WJ. Stress Cardiac Magnetic Resonance Imaging. J Am Coll Cardiol 2013; 62:839-41. [DOI: 10.1016/j.jacc.2013.04.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 04/30/2013] [Indexed: 10/26/2022]
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Meng Y, Wang J, Sun J, Zhang F, Willis P, Li J, Wang H, Zhang T, Soriano S, Qiu B, Yang X. 3.0-T MR imaging of intracoronary local delivery of motexafin gadolinium into coronary artery walls. Radiology 2013; 268:556-62. [PMID: 23513243 DOI: 10.1148/radiol.13121451] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To develop a technique with clinical 3.0-T magnetic resonance (MR) imaging to delineate local contrast agent distribution in coronary artery walls for potential molecular MR imaging-guided local gene or drug therapy of atherosclerotic coronary artery disease. MATERIALS AND METHODS This animal protocol was approved by the institutional animal care and use committee and was in compliance with the Guide for the Care and Use of Laboratory Animals. For in vitro confirmation, human arterial smooth muscle cells (SMCs) were used to determine capability of SMCs in uptake of motexafin gadolinium (MGd) and its optimal dose. For ex vivo evaluation, a 2-mL mixture of MGd and trypan blue was locally infused into coronary artery walls of six cadaveric pig hearts with MR monitoring and an MR imaging guidewire, surface coils, or both. For in vivo validation, the balloon catheter was placed into coronary arteries of seven living pigs, and the MGd and trypan blue mixture was infused into arterial walls with MR guidance. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of coronary artery walls were recorded by using different coils between pre- and postcontrast infusion, with subsequent histologic confirmation. Paired Student t tests were used to compare average SNRs and CNRs of arterial walls before and after contrast agent infusion with different coils. RESULTS SMCs could take up MGd with the optimal concentration at 150 µmol/L. Average SNR with the MR imaging guidewire and surface coil combination was significantly higher than that with the MR imaging guidewire only or with surface coils only (P < .05), and average SNR and CNR of postinfusion MR imaging was significantly higher than that of preinfusion MR imaging (P < .05). Histologic analysis was used to confirm successful intracoronary infiltration of MGd and trypan blue within coronary artery walls. CONCLUSION MR imaging can be used to delineate locally infused contrast agent distribution in coronary artery walls. This establishes groundwork for development of molecular MR imaging-guided intracoronary therapy.
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Affiliation(s)
- Yanfeng Meng
- Image-Guided Bio-Molecular Interventions Research, Department of Radiology, University of Washington School of Medicine, 815 Mercer St, Seattle, WA 98109, USA
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