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Pan Y, Varghese J, Tong MS, Yildiz VO, Azzu A, Gatehouse P, Wage R, Nielles-Vallespin S, Pennell DJ, Jin N, Bacher M, Hayes C, Speier P, Simonetti OP. Two-center validation of Pilot Tone based cardiac triggering of a comprehensive cardiovascular magnetic resonance examination. THE INTERNATIONAL JOURNAL OF CARDIOVASCULAR IMAGING 2024; 40:261-273. [PMID: 38082073 DOI: 10.1007/s10554-023-03002-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 10/31/2023] [Indexed: 12/26/2023]
Abstract
The electrocardiogram (ECG) signal is prone to distortions from gradient and radiofrequency interference and the magnetohydrodynamic effect during cardiovascular magnetic resonance imaging (CMR). Although Pilot Tone Cardiac (PTC) triggering has the potential to overcome these limitations, effectiveness across various CMR techniques has yet to be established. To evaluate the performance of PTC triggering in a comprehensive CMR exam. Fifteen volunteers and 20 patients were recruited at two centers. ECG triggered images were collected for comparison in a subset of sequences. The PTC trigger accuracy was evaluated against ECG in cine acquisitions. Two experienced readers scored image quality in PTC-triggered cine, late gadolinium enhancement (LGE), and T1- and T2-weighted dark-blood turbo spin echo (DB-TSE) images. Quantitative cardiac function, flow, and parametric mapping values obtained using PTC and ECG triggered sequences were compared. Breath-held segmented cine used for trigger timing analysis was collected in 15 volunteers and 14 patients. PTC calibration failed in three volunteers and one patient; ECG trigger recording failed in one patient. Out of 1987 total heartbeats, three mismatched trigger PTC-ECG pairs were found. Image quality scores showed no significant difference between PTC and ECG triggering. There was no significant difference found in quantitative measurements in volunteers. In patients, the only significant difference was found in post-contrast T1 (p = 0.04). ICC showed moderate to excellent agreement in all measurements. PTC performance was equivalent to ECG in terms of triggering consistency, image quality, and quantitative image measurements across multiple CMR applications.
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Affiliation(s)
- Yue Pan
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Juliet Varghese
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Matthew S Tong
- Department of Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Vedat O Yildiz
- Center for Biostatistics, Department of Biomedical Informatics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Alessia Azzu
- Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, London, UK
| | - Peter Gatehouse
- Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, London, UK
| | - Rick Wage
- Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, London, UK
| | | | - Dudley J Pennell
- Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, London, UK
| | - Ning Jin
- Cardiovascular MR R&D, Siemens Medical Solutions USA, Malvern, PA, USA
| | - Mario Bacher
- Siemens Healthineers AG, Erlangen, Germany
- Department of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | | | | | - Orlando P Simonetti
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
- Department of Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
- Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
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Pan Y, Varghese J, Tong MS, Yildiz VO, Azzu A, Gatehouse P, Wage R, Nielles-Vallespin S, Pennell D, Jin N, Bacher M, Hayes C, Speier P, Simonetti OP. Two-center validation of Pilot Tone Based Cardiac Triggering of a Comprehensive Cardiovascular Magnetic Resonance Examination. RESEARCH SQUARE 2023:rs.3.rs-3121723. [PMID: 37461505 PMCID: PMC10350216 DOI: 10.21203/rs.3.rs-3121723/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
Background The electrocardiogram (ECG) signal is prone to distortions from gradient and radiofrequency interference and the magnetohydrodynamic effect during cardiovascular magnetic resonance imaging (CMR). Although Pilot Tone Cardiac (PTC) triggering has the potential to overcome these limitations, effectiveness across various CMR techniques has yet to be established. Purpose To evaluate the performance of PTC triggering in a comprehensive CMR exam. Methods Fifteen volunteers and twenty patients were recruited at two centers. ECG triggered images were collected for comparison in a subset of sequences. The PTC trigger accuracy was evaluated against ECG in cine acquisitions. Two experienced readers scored image quality in PTC-triggered cine, late gadolinium enhancement (LGE), and T1- and T2-weighted dark-blood turbo spin echo (DB-TSE) images. Quantitative cardiac function, flow, and parametric mapping values obtained using PTC and ECG triggered sequences were compared. Results Breath-held segmented cine used for trigger timing analysis was collected in 15 volunteers and 14 patients. PTC calibration failed in three volunteers and one patient; ECG trigger recording failed in one patient. Out of 1987 total heartbeats, three mismatched trigger PTC-ECG pairs were found. Image quality scores showed no significant difference between PTC and ECG triggering. There was no significant difference found in quantitative measurements in volunteers. In patients, the only significant difference was found in post-contrast T1 (p = 0.04). ICC showed moderate to excellent agreement in all measurements. Conclusion PTC performance was equivalent to ECG in terms of triggering consistency, image quality, and quantitative image measurements across multiple CMR applications.
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Villagran Asiares A, Vitadello T, Bogdanovic B, Solari EL, McIntosh L, Schachoff S, Ibrahim T, Nekolla SG. Value of PET ECG gating in a cross-validation study of cardiac function assessment by PET/MR imaging. J Nucl Cardiol 2023; 30:1050-1060. [PMID: 36180767 PMCID: PMC10261229 DOI: 10.1007/s12350-022-03105-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 08/24/2022] [Indexed: 10/14/2022]
Abstract
BACKGROUND This work investigated the impact of different cardiac gating methods on the assessment of cardiac function by FDG-PET in a cross-validation PET/MR study. METHODS AND RESULTS MR- and PET-based left ventricular end-diastolic, end-systolic volumes, and ejection fraction (EDV, ESV, and EF) were delineated in 30 patients with a PET/MR examination. Cardiac PET imaging was performed using three ECG gating methods: fixed number of gates per beat (STD), STD with a beat acceptance window (STD-BR), and fixed gate duration (FW). High MR-PET correlations were found in all the values. ESVs correlated better than EDVs and EFs: Pearson's r coefficient [0.92, 0.92, 0.92] in ESV vs [0.75, 0.81, 0.80] in EDV and [0.79, 0.91, 0.87] in EF, for each method [STD, STD-BR, FW]. Biases with respect to MRI for all the evaluated PET methods were less than 13% in EDV, 5% in ESV, and 14% in EF, but with wide limits of agreements, in the range (59-68)% in EDV, (65-70)% in ESV, and (49-71)% in EF. STD showed the strongest disagreement, while there were no marked differences between STD-BR and FW. CONCLUSION Based on these findings, PET- and MR-based cardiac function parameters were highly correlated but in substantial disagreement with variabilities introduced by the selected PET ECG gating method. The most significant differences were associated with the ECG gating method susceptible to highly irregular beats, while similar performance was observed in the methods using uniform adjustment of gates width per beat with the beat acceptance window, and fixed gate width along all the beats. Thus, strict quality controls of R peak detection are needed to minimize its impact on the function assessment.
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Affiliation(s)
- Alberto Villagran Asiares
- Nuklearmedizinische Klinik und Poliklinik, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany.
| | - Teresa Vitadello
- Klinik und Poliklinik für Innere Medizin I, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Borjana Bogdanovic
- Nuklearmedizinische Klinik und Poliklinik, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Esteban Lucas Solari
- Nuklearmedizinische Klinik und Poliklinik, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Lachlan McIntosh
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Australia
| | - Sylvia Schachoff
- Nuklearmedizinische Klinik und Poliklinik, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Tareq Ibrahim
- Klinik und Poliklinik für Innere Medizin I, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Stephan G Nekolla
- Nuklearmedizinische Klinik und Poliklinik, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
- DZHK (German Centre for Cardiovascular Research), Partner site Munich Heart Alliance, Munich, Germany
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Rasul S, Calabretta R. Impact of ECG gating methods on the assessment of left ventricular cardiac function using PET/MRI. J Nucl Cardiol 2023; 30:1061-1064. [PMID: 36581772 PMCID: PMC10261213 DOI: 10.1007/s12350-022-03177-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 11/27/2022] [Indexed: 12/31/2022]
Affiliation(s)
- Sazan Rasul
- Department of Biomedical Imaging and Image-Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
| | - Raffaella Calabretta
- Department of Biomedical Imaging and Image-Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
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Schreiber LM, Lohr D, Baltes S, Vogel U, Elabyad IA, Bille M, Reiter T, Kosmala A, Gassenmaier T, Stefanescu MR, Kollmann A, Aures J, Schnitter F, Pali M, Ueda Y, Williams T, Christa M, Hofmann U, Bauer W, Gerull B, Zernecke A, Ergün S, Terekhov M. Ultra-high field cardiac MRI in large animals and humans for translational cardiovascular research. Front Cardiovasc Med 2023; 10:1068390. [PMID: 37255709 PMCID: PMC10225557 DOI: 10.3389/fcvm.2023.1068390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 04/04/2023] [Indexed: 06/01/2023] Open
Abstract
A key step in translational cardiovascular research is the use of large animal models to better understand normal and abnormal physiology, to test drugs or interventions, or to perform studies which would be considered unethical in human subjects. Ultrahigh field magnetic resonance imaging (UHF-MRI) at 7 T field strength is becoming increasingly available for imaging of the heart and, when compared to clinically established field strengths, promises better image quality and image information content, more precise functional analysis, potentially new image contrasts, and as all in-vivo imaging techniques, a reduction of the number of animals per study because of the possibility to scan every animal repeatedly. We present here a solution to the dual use problem of whole-body UHF-MRI systems, which are typically installed in clinical environments, to both UHF-MRI in large animals and humans. Moreover, we provide evidence that in such a research infrastructure UHF-MRI, and ideally combined with a standard small-bore UHF-MRI system, can contribute to a variety of spatial scales in translational cardiovascular research: from cardiac organoids, Zebra fish and rodent hearts to large animal models such as pigs and humans. We present pilot data from serial CINE, late gadolinium enhancement, and susceptibility weighted UHF-MRI in a myocardial infarction model over eight weeks. In 14 pigs which were delivered from a breeding facility in a national SARS-CoV-2 hotspot, we found no infection in the incoming pigs. Human scanning using CINE and phase contrast flow measurements provided good image quality of the left and right ventricle. Agreement of functional analysis between CINE and phase contrast MRI was excellent. MRI in arrested hearts or excised vascular tissue for MRI-based histologic imaging, structural imaging of myofiber and vascular smooth muscle cell architecture using high-resolution diffusion tensor imaging, and UHF-MRI for monitoring free radicals as a surrogate for MRI of reactive oxygen species in studies of oxidative stress are demonstrated. We conclude that UHF-MRI has the potential to become an important precision imaging modality in translational cardiovascular research.
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Affiliation(s)
- Laura M. Schreiber
- Department of Cardiovascular Imaging and Chair of Molecular and Cellular Imaging, Comprehensive Heart Failure Center Wuerzburg (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - David Lohr
- Department of Cardiovascular Imaging and Chair of Molecular and Cellular Imaging, Comprehensive Heart Failure Center Wuerzburg (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - Steffen Baltes
- Department of Cardiovascular Imaging and Chair of Molecular and Cellular Imaging, Comprehensive Heart Failure Center Wuerzburg (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - Ulrich Vogel
- Institute for Hygiene and Microbiology, University of Wuerzburg, Wuerzburg, Germany
| | - Ibrahim A. Elabyad
- Department of Cardiovascular Imaging and Chair of Molecular and Cellular Imaging, Comprehensive Heart Failure Center Wuerzburg (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - Maya Bille
- Department of Cardiovascular Imaging and Chair of Molecular and Cellular Imaging, Comprehensive Heart Failure Center Wuerzburg (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - Theresa Reiter
- Department of Cardiovascular Imaging and Chair of Molecular and Cellular Imaging, Comprehensive Heart Failure Center Wuerzburg (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
- Department of Internal Medicine I/Cardiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Aleksander Kosmala
- Department of Cardiovascular Imaging and Chair of Molecular and Cellular Imaging, Comprehensive Heart Failure Center Wuerzburg (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
- Department of Radiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Tobias Gassenmaier
- Department of Cardiovascular Imaging and Chair of Molecular and Cellular Imaging, Comprehensive Heart Failure Center Wuerzburg (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
- Department of Radiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Maria R. Stefanescu
- Department of Cardiovascular Imaging and Chair of Molecular and Cellular Imaging, Comprehensive Heart Failure Center Wuerzburg (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - Alena Kollmann
- Department of Cardiovascular Imaging and Chair of Molecular and Cellular Imaging, Comprehensive Heart Failure Center Wuerzburg (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - Julia Aures
- Department of Cardiovascular Imaging and Chair of Molecular and Cellular Imaging, Comprehensive Heart Failure Center Wuerzburg (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - Florian Schnitter
- Department of Internal Medicine I/Cardiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Mihaela Pali
- Department of Cardiovascular Imaging and Chair of Molecular and Cellular Imaging, Comprehensive Heart Failure Center Wuerzburg (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - Yuichiro Ueda
- Institute of Anatomy and Cell Biology, Julius-Maximilians-University, Wuerzburg, Germany
| | - Tatiana Williams
- Department of Cardiovascular Genetics, Comprehensive Heart Failure Center Wuerzburg, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Martin Christa
- Department of Internal Medicine I/Cardiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Ulrich Hofmann
- Department of Internal Medicine I/Cardiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Wolfgang Bauer
- Department of Internal Medicine I/Cardiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Brenda Gerull
- Department of Internal Medicine I/Cardiology, University Hospital Wuerzburg, Wuerzburg, Germany
- Department of Cardiovascular Genetics, Comprehensive Heart Failure Center Wuerzburg, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Alma Zernecke
- Institute of Experimental Biomedicine, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology, Julius-Maximilians-University, Wuerzburg, Germany
| | - Maxim Terekhov
- Department of Cardiovascular Imaging and Chair of Molecular and Cellular Imaging, Comprehensive Heart Failure Center Wuerzburg (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
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Madore B, Hess AT, van Niekerk AMJ, Hoinkiss DC, Hucker P, Zaitsev M, Afacan O, Günther M. External Hardware and Sensors, for Improved MRI. J Magn Reson Imaging 2023; 57:690-705. [PMID: 36326548 PMCID: PMC9957809 DOI: 10.1002/jmri.28472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 11/06/2022] Open
Abstract
Complex engineered systems are often equipped with suites of sensors and ancillary devices that monitor their performance and maintenance needs. MRI scanners are no different in this regard. Some of the ancillary devices available to support MRI equipment, the ones of particular interest here, have the distinction of actually participating in the image acquisition process itself. Most commonly, such devices are used to monitor physiological motion or variations in the scanner's imaging fields, allowing the imaging and/or reconstruction process to adapt as imaging conditions change. "Classic" examples include electrocardiography (ECG) leads and respiratory bellows to monitor cardiac and respiratory motion, which have been standard equipment in scan rooms since the early days of MRI. Since then, many additional sensors and devices have been proposed to support MRI acquisitions. The main physical properties that they measure may be primarily "mechanical" (eg acceleration, speed, and torque), "acoustic" (sound and ultrasound), "optical" (light and infrared), or "electromagnetic" in nature. A review of these ancillary devices, as currently available in clinical and research settings, is presented here. In our opinion, these devices are not in competition with each other: as long as they provide useful and unique information, do not interfere with each other and are not prohibitively cumbersome to use, they might find their proper place in future suites of sensors. In time, MRI acquisitions will likely include a plurality of complementary signals. A little like the microbiome that provides genetic diversity to organisms, these devices can provide signal diversity to MRI acquisitions and enrich measurements. Machine-learning (ML) algorithms are well suited at combining diverse input signals toward coherent outputs, and they could make use of all such information toward improved MRI capabilities. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 1.
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Affiliation(s)
- Bruno Madore
- Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Aaron T Hess
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Adam MJ van Niekerk
- Karolinska Institutet, Solna, Sweden
- Norwegian University of Science and Technology, Trondheim, Norway
| | | | - Patrick Hucker
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Maxim Zaitsev
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Onur Afacan
- Computational Radiology Laboratory, Department of Radiology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Matthias Günther
- Fraunhofer Institute for Digital Medicine MEVIS, Bremen, Germany
- University Bremen, Bremen, Germany
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7
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Lin L, Liu P, Sun G, Wang J, Liang D, Zheng H, Jin Z, Wang Y. Bi-ventricular assessment with cardiovascular magnetic resonance at 5 Tesla: A pilot study. Front Cardiovasc Med 2022; 9:913707. [PMID: 36172590 PMCID: PMC9510665 DOI: 10.3389/fcvm.2022.913707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 08/19/2022] [Indexed: 11/21/2022] Open
Abstract
Background Cardiovascular magnetic resonance (CMR) imaging at ultra-high fields (UHF) such as 7T has encountered many challenges such as faster T2* relaxation, stronger B0 and B1+ field inhomogeneities and additional safety concerns due to increased specific absorption rate (SAR) and peripheral nervous stimulation (PNS). Recently, a new line of 5T whole body MRI system has become available, and this study aims at evaluating the performance and benefits of this new UHF system for CMR imaging. Methods Gradient echo (GRE) CINE imaging was performed on healthy volunteers at both 5 and 3T, and was compared to balanced steady-state-free-procession (bSSFP) CINE imaging at 3T as reference. Higher spatial resolution GRE CINE scans were additionally performed at 5T. All scans at both fields were performed with ECG-gating and breath-holding. Image quality was blindly evaluated by two radiologists, and the cardiac functional parameters (e.g., EDV/ESV/mass/EF) of the left and right ventricles were measured for statistical analyses using the Wilcoxon signed-rank test and Bland-Altman analysis. Results Compared to 3T GRE CINE imaging, 5T GRE CINE imaging achieved comparable or improved image quality with significantly superior SNR and CNR, and it has also demonstrated excellent capability for high resolution (1.0 × 1.0 × 6.0 mm3) imaging. Functional assessments from 5T GRE CINE images were highly similar with the 3T bSSFP CINE reference. Conclusions This pilot study has presented the initial evaluation of CMR CINE imaging at 5T UHF, which yielded superior image quality and accurate functional quantification when compared to 3T counterparts. Along with reliable ECG gating, the new 5T UHF system has the potential to achieve well-balanced performance for CMR applications.
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Affiliation(s)
- Lu Lin
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Peijun Liu
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Gan Sun
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Medical Science Research Center, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jian Wang
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Dong Liang
- Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, China Academy of Sciences, Shenzhen, China
| | - Hairong Zheng
- Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, China Academy of Sciences, Shenzhen, China
| | - Zhengyu Jin
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yining Wang
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- *Correspondence: Yining Wang
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Qin C, Murali S, Lee E, Supramaniam V, Hausenloy DJ, Obungoloch J, Brecher J, Lin R, Ding H, Akudjedu TN, Anazodo UC, Jagannathan NR, Ntusi NAB, Simonetti OP, Campbell-Washburn AE, Niendorf T, Mammen R, Adeleke S. Sustainable low-field cardiovascular magnetic resonance in changing healthcare systems. Eur Heart J Cardiovasc Imaging 2022; 23:e246-e260. [PMID: 35157038 PMCID: PMC9159744 DOI: 10.1093/ehjci/jeab286] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/14/2021] [Indexed: 11/14/2022] Open
Abstract
Cardiovascular disease continues to be a major burden facing healthcare systems worldwide. In the developed world, cardiovascular magnetic resonance (CMR) is a well-established non-invasive imaging modality in the diagnosis of cardiovascular disease. However, there is significant global inequality in availability and access to CMR due to its high cost, technical demands as well as existing disparities in healthcare and technical infrastructures across high-income and low-income countries. Recent renewed interest in low-field CMR has been spurred by the clinical need to provide sustainable imaging technology capable of yielding diagnosticquality images whilst also being tailored to the local populations and healthcare ecosystems. This review aims to evaluate the technical, practical and cost considerations of low field CMR whilst also exploring the key barriers to implementing sustainable MRI in both the developing and developed world.
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Affiliation(s)
- Cathy Qin
- Department of Imaging, Imperial College Healthcare NHS Trust, London, UK
| | - Sanjana Murali
- Department of Imaging, Imperial College Healthcare NHS Trust, London, UK
| | - Elsa Lee
- School of Medicine, Faculty of Medicine, Imperial College London, London, UK
| | | | - Derek J Hausenloy
- Division of Medicine, University College London, London, UK.,Cardiovascular & Metabolic Disorders Program, Duke-National University of Singapore Medical School, Singapore, Singapore.,National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore.,Yong Loo Lin School of Medicine, National University Singapore, Singapore, Singapore.,Hatter Cardiovascular Institue, UCL Institute of Cardiovascular Sciences, University College London, London, UK.,Cardiovascular Research Center, College of Medical and Health Sciences, Asia University, Taichung, Taiwan
| | - Johnes Obungoloch
- Department of Biomedical Engineering, Mbarara University of Science and Technology, Mbarara, Uganda
| | | | - Rongyu Lin
- School of Medicine, University College London, London, UK
| | - Hao Ding
- Department of Imaging, Imperial College Healthcare NHS Trust, London, UK
| | - Theophilus N Akudjedu
- Institute of Medical Imaging and Visualisation, Faculty of Health and Social Science, Bournemouth University, Poole, UK
| | | | - Naranamangalam R Jagannathan
- Department of Electrical Engineering, Indian Institute of Technology, Chennai, India.,Department of Radiology, Sri Ramachandra University Medical College, Chennai, India.,Department of Radiology, Chettinad Hospital and Research Institute, Kelambakkam, India
| | - Ntobeko A B Ntusi
- Department of Medicine, University of Cape Town and Groote Schuur Hospital, Cape Town, Western Cape, South Africa
| | - Orlando P Simonetti
- Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH, USA.,Department of Radiology, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Adrienne E Campbell-Washburn
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück Centre for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Regina Mammen
- Department of Cardiology, The Essex Cardiothoracic Centre, Basildon, UK
| | - Sola Adeleke
- School of Cancer & Pharmaceutical Sciences, King's College London, Queen Square, London WC1N 3BG, UK.,High Dimensional Neurology, Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, University College London, London, UK
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Wang W, Weiss S, den Brinker AC, Wuelbern JH, Tormo AGI, Pappous I, Senegas J. Fundamentals of Camera-PPG based Magnetic Resonance Imaging. IEEE J Biomed Health Inform 2021; 26:4378-4389. [PMID: 34928810 DOI: 10.1109/jbhi.2021.3136603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In Magnetic Resonance Imaging (MRI), cardiac triggering that synchronizes data acquisition with cardiac contractions is an essential technique for acquiring high-quality images. Triggering is typically based on the Electrocardiogram (ECG) signal (e.g. R-peak). Since ECG acquisition involves extra workflow steps like electrode placement and ECG signals are usually disturbed by magnetic fields in high Magnetic Resonance (MR) systems, we explored camera-based photoplethysmography (PPG) as an alternative. We used the in-bore camera of a clinical MR system to investigate the feasibility and challenges of camera-based cardiac triggering. Data from ECG, finger oximeter and camera were synchronously collected. We found that that camera-PPG provides a higher availability of signal (and trigger) measurement, and the PPG signals measured from the forehead show considerably less delay w.r.t. the coupled ECG R-peak than the finger PPG signals in terms of trigger detection. The insights obtained in this study provide a basis for an envisioned system design phase.
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10
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Abstract
Especially after the launch of 7 T, the ultrahigh magnetic field (UHF) imaging community achieved critically important strides in our understanding of the physics of radiofrequency interactions in the human body, which in turn has led to solutions for the challenges posed by such UHFs. As a result, the originally obtained poor image quality has progressed to the high-quality and high-resolution images obtained at 7 T and now at 10.5 T in the human torso. Despite these tremendous advances, work still remains to further improve the image quality and fully capitalize on the potential advantages UHF has to offer.
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11
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Hamilton-Craig C, Stäeb D, Al Najjar A, O’Brien K, Crawford W, Fletcher S, Barth M, Galloway G. 7-Tesla Functional Cardiovascular MR Using Vectorcardiographic Triggering-Overcoming the Magnetohydrodynamic Effect. ACTA ACUST UNITED AC 2021; 7:323-332. [PMID: 34449723 PMCID: PMC8396263 DOI: 10.3390/tomography7030029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/14/2021] [Accepted: 06/19/2021] [Indexed: 11/16/2022]
Abstract
Objective: Ultra-high-field B0 ≥ 7 tesla (7T) cardiovascular magnetic resonance (CMR) offers increased resolution. However, electrocardiogram (ECG) gating is impacted by the magneto-hydrodynamic effect distorting the ECG trace. We explored the technical feasibility of a 7T magnetic resonance scanner using an ECG trigger learning algorithm to quantitatively assess cardiac volumes and vascular flow. Methods: 7T scans were performed on 10 healthy volunteers on a whole-body research MRI MR scanner (Siemens Healthineers, Erlangen, Germany) with 8 channel Tx/32 channels Rx cardiac coils (MRI Tools GmbH, Berlin, Germany). Vectorcardiogram ECG was performed using a learning phase outside of the magnetic field, with a trigger algorithm overcoming severe ECG signal distortions. Vectorcardiograms were quantitatively analyzed for false negative and false positive events. Cine CMR was performed after 3rd-order B0 shimming using a high-resolution breath-held ECG-retro-gated segmented spoiled gradient echo, and 2D phase contrast flow imaging. Artefacts were assessed using a semi-quantitative scale. Results: 7T CMR scans were acquired in all patients (100%) using the vectorcardiogram learning method. 3,142 R-waves were quantitatively analyzed, yielding sensitivity of 97.6% and specificity of 98.7%. Mean image quality score was 0.9, sufficient to quantitate both cardiac volumes, ejection fraction, and aortic and pulmonary blood flow. Mean left ventricular ejection fraction was 56.4%, right ventricular ejection fraction was 51.4%. Conclusion: Reliable cardiac ECG triggering is feasible in healthy volunteers at 7T utilizing a state-of-the-art three-lead trigger device despite signal distortion from the magnetohydrodynamic effect. This provides sufficient image quality for quantitative analysis. Other ultra-high-field imaging applications such as human brain functional MRI with physiologic noise correction may benefit from this method of ECG triggering.
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Affiliation(s)
- Christian Hamilton-Craig
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4000, Australia; (D.S.); (A.A.N.); (W.C.); (S.F.); (M.B.); (G.G.)
- Correspondence:
| | - Daniel Stäeb
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4000, Australia; (D.S.); (A.A.N.); (W.C.); (S.F.); (M.B.); (G.G.)
- MR Research Collaborations, Siemens Healthineers Pty Ltd., Bayswater, VIC 3153, Australia;
| | - Aiman Al Najjar
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4000, Australia; (D.S.); (A.A.N.); (W.C.); (S.F.); (M.B.); (G.G.)
| | - Kieran O’Brien
- MR Research Collaborations, Siemens Healthineers Pty Ltd., Bayswater, VIC 3153, Australia;
| | - William Crawford
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4000, Australia; (D.S.); (A.A.N.); (W.C.); (S.F.); (M.B.); (G.G.)
- Department of Medical Science, University of Oxford, Oxford 01865, UK
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD 4000, Australia
| | - Sabine Fletcher
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4000, Australia; (D.S.); (A.A.N.); (W.C.); (S.F.); (M.B.); (G.G.)
| | - Markus Barth
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4000, Australia; (D.S.); (A.A.N.); (W.C.); (S.F.); (M.B.); (G.G.)
| | - Graham Galloway
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD 4000, Australia; (D.S.); (A.A.N.); (W.C.); (S.F.); (M.B.); (G.G.)
- Imaging Technology, Translational Research Institute, Brisbane, QLD 4000, Australia
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12
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Guo R, Weingärtner S, Šiurytė P, T Stoeck C, Füetterer M, E Campbell-Washburn A, Suinesiaputra A, Jerosch-Herold M, Nezafat R. Emerging Techniques in Cardiac Magnetic Resonance Imaging. J Magn Reson Imaging 2021; 55:1043-1059. [PMID: 34331487 DOI: 10.1002/jmri.27848] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 07/08/2021] [Accepted: 07/09/2021] [Indexed: 11/10/2022] Open
Abstract
Cardiovascular disease is the leading cause of death and a significant contributor of health care costs. Noninvasive imaging plays an essential role in the management of patients with cardiovascular disease. Cardiac magnetic resonance (MR) can noninvasively assess heart and vascular abnormalities, including biventricular structure/function, blood hemodynamics, myocardial tissue composition, microstructure, perfusion, metabolism, coronary microvascular function, and aortic distensibility/stiffness. Its ability to characterize myocardial tissue composition is unique among alternative imaging modalities in cardiovascular disease. Significant growth in cardiac MR utilization, particularly in Europe in the last decade, has laid the necessary clinical groundwork to position cardiac MR as an important imaging modality in the workup of patients with cardiovascular disease. Although lack of availability, limited training, physician hesitation, and reimbursement issues have hampered widespread clinical adoption of cardiac MR in the United States, growing clinical evidence will ultimately overcome these challenges. Advances in cardiac MR techniques, particularly faster image acquisition, quantitative myocardial tissue characterization, and image analysis have been critical to its growth. In this review article, we discuss recent advances in established and emerging cardiac MR techniques that are expected to strengthen its capability in managing patients with cardiovascular disease. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 1.
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Affiliation(s)
- Rui Guo
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Sebastian Weingärtner
- Department of Imaging Physics, Magnetic Resonance Systems Lab, Delft University of Technology, Delft, The Netherlands
| | - Paulina Šiurytė
- Department of Imaging Physics, Magnetic Resonance Systems Lab, Delft University of Technology, Delft, The Netherlands
| | - Christian T Stoeck
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Maximilian Füetterer
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Adrienne E Campbell-Washburn
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Avan Suinesiaputra
- Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, UK
| | - Michael Jerosch-Herold
- Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Reza Nezafat
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
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13
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On the way to routine cardiac MRI at 7 Tesla - a pilot study on consecutive 84 examinations. PLoS One 2021; 16:e0252797. [PMID: 34297720 PMCID: PMC8301632 DOI: 10.1371/journal.pone.0252797] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 05/23/2021] [Indexed: 11/29/2022] Open
Abstract
Introduction Cardiac magnetic resonance (CMR) at ultrahigh field (UHF) offers the potential of high resolution and fast image acquisition. Both technical and physiological challenges associated with CMR at 7T require specific hardware and pulse sequences. This study aimed to assess the current status and existing, publicly available technology regarding the potential of a clinical application of 7T CMR. Methods Using a 7T MRI scanner and a commercially available radiofrequency coil, a total of 84 CMR examinations on 72 healthy volunteers (32 males, age 19–70 years, weight 50–103 kg) were obtained. Both electrocardiographic and acoustic triggering were employed. The data were analyzed regarding the diagnostic image quality and the influence of patient and hardware dependent factors. 50 complete short axis stacks and 35 four chamber CINE views were used for left ventricular (LV) and right ventricular (RV), mono-planar LV function, and RV fractional area change (FAC). Twenty-seven data sets included aortic flow measurements that were used to calculate stroke volumes. Subjective acceptance was obtained from all volunteers with a standardized questionnaire. Results Functional analysis showed good functions of LV (mean EF 56%), RV (mean EF 59%) and RV FAC (mean FAC 52%). Flow measurements showed congruent results with both ECG and ACT triggering. No significant influence of experimental parameters on the image quality of the LV was detected. Small fractions of 5.4% of LV and 2.5% of RV segments showed a non-diagnostic image quality. The nominal flip angle significantly influenced the RV image quality. Conclusion The results demonstrate that already now a commercially available 7T MRI system, without major methods developments, allows for a solid morphological and functional analysis similar to the clinically established CMR routine approach. This opens the door towards combing routine CMR in patients with development of advanced 7T technology.
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14
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Wampl S, Körner T, Valkovič L, Trattnig S, Wolzt M, Meyerspeer M, Schmid AI. Investigating the effect of trigger delay on cardiac 31P MRS signals. Sci Rep 2021; 11:9268. [PMID: 33927234 PMCID: PMC8085231 DOI: 10.1038/s41598-021-87063-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/22/2021] [Indexed: 01/15/2023] Open
Abstract
The heart’s geometry and its metabolic activity vary over the cardiac cycle. The effect of these fluctuations on phosphorus (31P) magnetic resonance spectroscopy (MRS) data quality and metabolite ratios was investigated. 12 healthy volunteers were measured using a 7 T MR scanner and a cardiac 31P-1H loop coil. 31P chemical shift imaging data were acquired untriggered and at four different times during the cardiac cycle using acoustic triggering. Signals of adenosine-triphosphate (ATP), phosphocreatine (PCr), inorganic phosphate (Pi) and 2,3-diphosphoglycerate (2,3-DPG) and their fit quality as Cramér-Rao lower bounds (CRLB) were quantified including corrections for contamination by 31P signals from blood, flip angle, saturation and total acquisition time. The myocardial filling factor was estimated from cine short axis views. The corrected signals of PCr and \documentclass[12pt]{minimal}
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\begin{document}$$\gamma$$\end{document}γ-ATP were higher during end-systole and lower during diastasis than in untriggered acquisitions (\documentclass[12pt]{minimal}
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\begin{document}$$P<0.05$$\end{document}P<0.05). Signal intensities of untriggered scans were between those with triggering to end-systole and diastasis. Fit quality of PCr and \documentclass[12pt]{minimal}
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\begin{document}$$\gamma$$\end{document}γ-ATP peaks was best during end-systole when blood contamination of ATP and Pi signals was lowest. While metabolite ratios and pH remained stable over the cardiac cycle, signal amplitudes correlated strongly with myocardial voxel filling. Triggering of cardiac 31P MRS acquisitions improves signal amplitudes and fit quality if the trigger delay is set to end-systole. We conclude that triggering to end-systole is superior to triggering to diastasis.
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Affiliation(s)
- Stefan Wampl
- Medical University of Vienna, High Field MR Center, Center for Medical Physics and Biomedical Engineering, Vienna, 1090, Austria
| | - Tito Körner
- Medical University of Vienna, High Field MR Center, Center for Medical Physics and Biomedical Engineering, Vienna, 1090, Austria
| | - Ladislav Valkovič
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), RDM Cardiovascular Medicine, University of Oxford, Oxford, OX3 9DU, United Kingdom.,Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, 814 04, Slovakia
| | - Siegfried Trattnig
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, High Field MR Center, Vienna, 1090, Austria
| | - Michael Wolzt
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, 1090, Austria
| | - Martin Meyerspeer
- Medical University of Vienna, High Field MR Center, Center for Medical Physics and Biomedical Engineering, Vienna, 1090, Austria
| | - Albrecht Ingo Schmid
- Medical University of Vienna, High Field MR Center, Center for Medical Physics and Biomedical Engineering, Vienna, 1090, Austria.
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15
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von Kleist H, Buehrer M, Kozerke S, Saengsin K, Harrington JK, Powell AJ, Moghari MH. Cardiac self-gating using blind source separation for 2D cine cardiovascular magnetic resonance imaging. Magn Reson Imaging 2021; 81:42-52. [PMID: 33905835 DOI: 10.1016/j.mri.2021.04.008] [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: 01/10/2021] [Revised: 04/11/2021] [Accepted: 04/21/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE To develop and validate a new cardiac self-gating algorithm using blind source separation for 2D cine steady-state free precession (SSFP) imaging. METHODS A standard cine SSFP sequence was modified so that the center point of k-space was sampled with each excitation. The center points of k-space were processed by 4 blind source separation methods, and used to detect heartbeats and assign k-space data to appropriate time points in the cardiac cycle. The proposed self-gating technique was prospectively validated in 8 patients against the standard electrocardiogram (ECG)-gating method by comparing the cardiac cycle lengths, image quality metrics, and ventricular volume measurements. RESULTS There was close agreement between the cardiac cycle length using the ECG- and self-gating methods (bias 0.0 bpm, 95% limits of agreement ±2.1 bpm). The image quality metrics were not significantly different between the ECG- and self-gated images. The ventricular volumes, stroke volumes, and mass measured from self-gated images were all comparable with those from ECG-gated images (all biases <5%). CONCLUSION The self-gating method yielded comparable cardiac cycle length, image quality, and ventricular measurements compared with standard ECG-gated cine imaging. It may simplify patient preparation, be more robust when there is arrhythmia, and allow cardiac gating at higher field strengths.
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Affiliation(s)
- Henrik von Kleist
- Department of Cardiology, Boston Children's Hospital, and Department of Pediatrics, Harvard Medical School, Boston, MA, USA; Department of Informatics, Technical University of Munich, Garching, Germany.
| | - Martin Buehrer
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Kwannapas Saengsin
- Department of Cardiology, Boston Children's Hospital, and Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Jamie K Harrington
- Department of Cardiology, Boston Children's Hospital, and Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Andrew J Powell
- Department of Cardiology, Boston Children's Hospital, and Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Mehdi H Moghari
- Department of Cardiology, Boston Children's Hospital, and Department of Pediatrics, Harvard Medical School, Boston, MA, USA
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16
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Willemink MJ, Varga-Szemes A, Schoepf UJ, Codari M, Nieman K, Fleischmann D, Mastrodicasa D. Emerging methods for the characterization of ischemic heart disease: ultrafast Doppler angiography, micro-CT, photon-counting CT, novel MRI and PET techniques, and artificial intelligence. Eur Radiol Exp 2021; 5:12. [PMID: 33763754 PMCID: PMC7991013 DOI: 10.1186/s41747-021-00207-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 01/22/2021] [Indexed: 12/24/2022] Open
Abstract
After an ischemic event, disruptive changes in the healthy myocardium may gradually develop and may ultimately turn into fibrotic scar. While these structural changes have been described by conventional imaging modalities mostly on a macroscopic scale-i.e., late gadolinium enhancement at magnetic resonance imaging (MRI)-in recent years, novel imaging methods have shown the potential to unveil an even more detailed picture of the postischemic myocardial phenomena. These new methods may bring advances in the understanding of ischemic heart disease with potential major changes in the current clinical practice. In this review article, we provide an overview of the emerging methods for the non-invasive characterization of ischemic heart disease, including coronary ultrafast Doppler angiography, photon-counting computed tomography (CT), micro-CT (for preclinical studies), low-field and ultrahigh-field MRI, and 11C-methionine positron emission tomography. In addition, we discuss new opportunities brought by artificial intelligence, while addressing promising future scenarios and the challenges for the application of artificial intelligence in the field of cardiac imaging.
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Affiliation(s)
- Martin J. Willemink
- grid.168010.e0000000419368956Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94035 USA
| | - Akos Varga-Szemes
- grid.259828.c0000 0001 2189 3475Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC USA
| | - U. Joseph Schoepf
- grid.259828.c0000 0001 2189 3475Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC USA
| | - Marina Codari
- grid.168010.e0000000419368956Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94035 USA
| | - Koen Nieman
- grid.168010.e0000000419368956Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA USA ,Stanford Cardiovascular Institute, Stanford, CA 94305 USA
| | - Dominik Fleischmann
- grid.168010.e0000000419368956Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94035 USA ,Stanford Cardiovascular Institute, Stanford, CA 94305 USA
| | - Domenico Mastrodicasa
- Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94035, USA. .,Stanford Cardiovascular Institute, Stanford, CA, 94305, USA.
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17
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Ladrova M, Martinek R, Nedoma J, Hanzlikova P, Nelson MD, Kahankova R, Brablik J, Kolarik J. Monitoring and Synchronization of Cardiac and Respiratory Traces in Magnetic Resonance Imaging: A Review. IEEE Rev Biomed Eng 2021; 15:200-221. [PMID: 33513108 DOI: 10.1109/rbme.2021.3055550] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Synchronization of human vital signs, namely the cardiac cycle and respiratory excursions, is necessary during magnetic resonance imaging of the cardiovascular system and the abdominal cavity to achieve optimal image quality with minimized artifacts. This review summarizes techniques currently available in clinical practice, as well as methods under development, outlines the benefits and disadvantages of each approach, and offers some unique solutions for consideration.
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18
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Markenroth Bloch K, Kording F, Töger J. Doppler ultrasound cardiac gating of intracranial flow at 7T. BMC Med Imaging 2020; 20:128. [PMID: 33297985 PMCID: PMC7724705 DOI: 10.1186/s12880-020-00523-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 11/15/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ultra-high field magnetic resonance imaging (MR) may be used to improve intracranial blood flow measurements. However, standard cardiac synchronization methods tend to fail at ultra-high field MR. Therefore, this study aims to investigate an alternative synchronization technique using Doppler ultrasound. METHODS Healthy subjects (n = 9) were examined with 7T MR. Flow was measured in the M1-branch of the middle cerebral artery (MCA) and in the cerebral aqueduct (CA) using through-plane phase contrast (2D flow). Flow in the circle of Willis was measured with three-dimensional, three-directional phase contrast (4D flow). Scans were gated with Doppler ultrasound (DUS) and electrocardiogram (ECG), and pulse oximetry data (POX) was collected simultaneously. False negative and false positive trigger events were counted for ECG, DUS and POX, and quantitative flow measures were compared. RESULTS There were fewer false positive triggers for DUS compared to ECG (5.3 ± 11 vs. 25 ± 31, p = 0.031), while no other measured parameters differed significantly. Net blood flow in M1 was similar between DUS and ECG for 2D flow (1.5 ± 0.39 vs. 1.6 ± 0.41, bias ± 1.96SD: - 0.021 ± 0.36) and 4D flow (1.8 ± 0.48 vs. 9 ± 0.59, bias ± 1.96SD: - 0.086 ± 0.57 ml). Net CSF flow per heart beat in the CA was also similar for DUS and ECG (3.6 ± 2.1 vs. 3.0 ± 5.8, bias ± 1.96SD: 0.61 ± 13.6 μl). CONCLUSION Gating with DUS produced fewer false trigger events than using ECG, with similar quantitative flow values. DUS gating is a promising technique for cardiac synchronization at 7T.
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Affiliation(s)
- Karin Markenroth Bloch
- The Swedish National 7T Facility, Lund University Bioimaging Center, Lund University, Klinikgatan 32, BMC D11, 22242, Lund, Sweden.
| | - Fabian Kording
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg- Eppendorf, Hamburg, Germany.,Northh Medical GmbH, Röntgenstraße 24, 22335, Hamburg, Germany
| | - Johannes Töger
- Diagnostic Radiology, Department of Clinical Sciences Lund, Lund University and Skane University Hospital Lund, Lund, Sweden
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19
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Ludwig J, Speier P, Seifert F, Schaeffter T, Kolbitsch C. Pilot tone-based motion correction for prospective respiratory compensated cardiac cine MRI. Magn Reson Med 2020; 85:2403-2416. [PMID: 33226699 DOI: 10.1002/mrm.28580] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 09/24/2020] [Accepted: 10/12/2020] [Indexed: 12/30/2022]
Abstract
PURPOSE To evaluate prospective motion correction using the pilot tone (PT) as a quantitative respiratory motion signal with high temporal resolution for cardiac cine images during free breathing. METHODS Before cine data acquisition, a short prescan was performed, calibrating the PT to the respiratory-induced heart motion using respiratory-resolved real-time images. The calibrated PT was then applied for nearly real-time prospective motion correction of cine MRI through slice tracking (ie, updating the slice position before every readout). Additionally, in-plane motion correction was performed retrospectively also based on the calibrated PT data. The proposed method was evaluated in a moving phantom and 10 healthy volunteers. RESULTS The PT showed very good correlation to the phantom motion. In volunteer studies using a long-term scan over 7.96 ± 1.40 min, the mean absolute error between registered and predicted motion from the PT was 1.44 ± 0.46 mm in head-feet and 0.46 ± 0.07 mm in anterior-posterior direction. Irregular breathing could also be corrected well with the PT. The PT motion correction leads to a significant improvement of contrast-to-noise ratio by 68% (P ≤ .01) between blood pool and myocardium and sharpness of endocardium by 24% (P = .04) in comparison to uncorrected data. The image score, which refers to the cine image quality, has improved with the utilization of the proposed PT motion correction. CONCLUSION The proposed approach provides respiratory motion-corrected cine images of the heart with improved image quality and a high scan efficiency using the PT. The PT is independent of the MR acquisition, making this a very flexible motion-correction approach.
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Affiliation(s)
- Juliane Ludwig
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | | | - Frank Seifert
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Tobias Schaeffter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany.,Technische Universität Berlin, Biomedical Engineering, Berlin, Germany
| | - Christoph Kolbitsch
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
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20
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Wiesemann S, Schmitter S, Demir A, Prothmann M, Schwenke C, Chawla A, von Knobelsdorff-Brenkenhoff F, Greiser A, Jin N, Bollache E, Markl M, Schulz-Menger J. Impact of sequence type and field strength (1.5, 3, and 7T) on 4D flow MRI hemodynamic aortic parameters in healthy volunteers. Magn Reson Med 2020; 85:721-733. [PMID: 32754969 DOI: 10.1002/mrm.28450] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 06/22/2020] [Accepted: 07/08/2020] [Indexed: 01/15/2023]
Abstract
PURPOSE 4D flow magnetic resonance imaging (4D-MRI) allows time-resolved visualization of blood flow patterns, quantification of volumes, velocities, and advanced parameters, such as wall shear stress (WSS). As 4D-MRI enters the clinical arena, standardization and awareness of confounders are important. Our aim was to evaluate the equivalence of 4D flow-derived aortic hemodynamics in healthy volunteers using different sequences and field strengths. METHODS 4D-MRI was acquired in 10 healthy volunteers at 1.5T using three different prototype sequences, at 3T and at 7T (Siemens Healthineers). After evaluation of diagnostic quality in three segments (ascending-, descending aorta, aortic arch), peak velocity, flow volumes, and WSS were investigated. Equivalence limits for comparison of field strengths/sequences were based on the limits of Bland-Altman analyses of the intraobserver variability. RESULTS Non-diagnostic quality was found in 10/144 segments, 9/10 were obtained at 7T. Apart for the comparison of forward flow between sequence 1 and 3, the differences in measurements between field strengths/sequences exceeded the range of agreement. Significant differences were found between field strengths/sequences for forward flow (1.5T vs. 3T, 3T vs. 7T, sequence 1 vs. 3, 2 vs. 3 [P < .001]), WSS (1.5T vs. 3T [P < .05], sequence 1 vs. 2, 1 vs. 3, 2 vs. 3 [P < .001]), and peak velocity (1.5T vs. 7T, sequence 1 vs. 3 [P > .001]). All parameters at all field strengths/with all sequences correlated moderately to strongly (r ≥ 0.5). CONCLUSION Data from all sequences could be acquired and resulting images showed sufficient quality for further analysis. However, the variability of the measurements of peak velocity, flow volumes, and WSS was higher when comparing field strengths/sequences as the equivalence limits defined by the intraobserver assessments.
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Affiliation(s)
- Stephanie Wiesemann
- Department of Cardiology and Nephrology, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Hospital Berlin Buch, Berlin, Germany.,DZHK (German Center for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Sebastian Schmitter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Aylin Demir
- Department of Cardiology and Nephrology, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Hospital Berlin Buch, Berlin, Germany
| | - Marcel Prothmann
- Department of Cardiology and Nephrology, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Hospital Berlin Buch, Berlin, Germany
| | | | - Ashish Chawla
- Khoo Teck Puat Hospital, Yishun Central, Singapore, Singapore
| | - Florian von Knobelsdorff-Brenkenhoff
- Department of Cardiology and Nephrology, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Hospital Berlin Buch, Berlin, Germany.,Clinic Agatharied, Department of Cardiology, Ludwig-Maximilians-University Munich, Hausham, Germany
| | | | - Ning Jin
- Siemens Medical Solutions, Columbus, Ohio, USA
| | - Emilie Bollache
- Sorbonne Université, CNRS, INSERM, Laboratoire d'Imagerie Biomédicale, LIB, Paris, France
| | - Michael Markl
- Department of Radiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA
| | - Jeanette Schulz-Menger
- Department of Cardiology and Nephrology, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Hospital Berlin Buch, Berlin, Germany.,DZHK (German Center for Cardiovascular Research), partner site Berlin, Berlin, Germany
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21
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Hock M, Terekhov M, Stefanescu MR, Lohr D, Herz S, Reiter T, Ankenbrand M, Kosmala A, Gassenmaier T, Juchem C, Schreiber LM. B 0 shimming of the human heart at 7T. Magn Reson Med 2020; 85:182-196. [PMID: 32700791 DOI: 10.1002/mrm.28423] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 06/19/2020] [Accepted: 06/22/2020] [Indexed: 01/31/2023]
Abstract
PURPOSE Inhomogeneities of the static magnetic B0 field are a major limiting factor in cardiac MRI at ultrahigh field (≥ 7T), as they result in signal loss and image distortions. Different magnetic susceptibilities of the myocardium and surrounding tissue in combination with cardiac motion lead to strong spatio-temporal B0 -field inhomogeneities, and their homogenization (B0 shimming) is a prerequisite. Limitations of state-of-the-art shimming are described, regional B0 variations are measured, and a methodology for spherical harmonics shimming of the B0 field within the human myocardium is proposed. METHODS The spatial B0 -field distribution in the heart was analyzed as well as temporal B0 -field variations in the myocardium over the cardiac cycle. Different shim region-of-interest selections were compared, and hardware limitations of spherical harmonics B0 shimming were evaluated by calibration-based B0 -field modeling. The role of third-order spherical harmonics terms was analyzed as well as potential benefits from cardiac phase-specific shimming. RESULTS The strongest B0 -field inhomogeneities were observed in localized spots within the left-ventricular and right-ventricular myocardium and varied between systolic and diastolic cardiac phases. An anatomy-driven shim region-of-interest selection allowed for improved B0 -field homogeneity compared with a standard shim region-of-interest cuboid. Third-order spherical harmonics terms were demonstrated to be beneficial for shimming of these myocardial B0 -field inhomogeneities. Initial results from the in vivo implementation of a potential shim strategy were obtained. Simulated cardiac phase-specific shimming was performed, and a shim term-by-term analysis revealed periodic variations of required currents. CONCLUSION Challenges in state-of-the-art B0 shimming of the human heart at 7 T were described. Cardiac phase-specific shimming strategies were found to be superior to vendor-supplied shimming.
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Affiliation(s)
- Michael Hock
- Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - Maxim Terekhov
- Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - Maria Roxana Stefanescu
- Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - David Lohr
- Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - Stefan Herz
- Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany.,Department of Diagnostic and Interventional Radiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Theresa Reiter
- Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany.,Department of Internal Medicine I, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Markus Ankenbrand
- Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
| | - Aleksander Kosmala
- Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany.,Department of Diagnostic and Interventional Radiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Tobias Gassenmaier
- Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany.,Department of Diagnostic and Interventional Radiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Christoph Juchem
- Department of Biomedical Engineering, Columbia University, New York, New York, USA.,Department of Radiology, Columbia University, New York, New York, USA
| | - Laura Maria Schreiber
- Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany
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22
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Situ Y, Birch SCM, Moreyra C, Holloway CJ. Cardiovascular magnetic resonance imaging for structural heart disease. Cardiovasc Diagn Ther 2020; 10:361-375. [PMID: 32420118 DOI: 10.21037/cdt.2019.06.02] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Cardiovascular magnetic resonance (CMR) has increasingly become a powerful imaging technique over the past few decades due to increasing knowledge about clinical applications, operator experience and technological advances, including the introduction of high field strength magnets, leading to improved signal-to-noise ratio. Its success is attributed to the free choice of imaging planes, the wide variety of imaging techniques, and the lack of harmful radiation. Developments in CMR have led to the accurate evaluation of cardiac structure, function and tissues characterisation, so this non-invasive technique has become a powerful tool for a broad range of cardiac pathologies. This review will provide an introduction of magnetic resonance imaging (MRI) physics, an overview of the current techniques and clinical application of CMR in structural heart disease, and illustrated examples of its use in clinical practice.
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Affiliation(s)
- Yiling Situ
- St Vincent's Hospital Sydney, New South Wales, Australia.,St Vincent's Clinical School, University of New South Wales, Kensington, Australia.,Victor Chang Cardiac Research Institute, Darlinghurst, Australia
| | | | - Camila Moreyra
- St Vincent's Hospital Sydney, New South Wales, Australia
| | - Cameron J Holloway
- St Vincent's Hospital Sydney, New South Wales, Australia.,St Vincent's Clinical School, University of New South Wales, Kensington, Australia.,Victor Chang Cardiac Research Institute, Darlinghurst, Australia
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23
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He X, Ertürk MA, Grant A, Wu X, Lagore RL, DelaBarre L, Eryaman Y, Adriany G, Auerbach EJ, Van de Moortele PF, Uğurbil K, Metzger GJ. First in-vivo human imaging at 10.5T: Imaging the body at 447 MHz. Magn Reson Med 2019; 84:289-303. [PMID: 31846121 DOI: 10.1002/mrm.28131] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 11/25/2019] [Accepted: 11/26/2019] [Indexed: 01/31/2023]
Abstract
PURPOSE To investigate the feasibility of imaging the human torso and to evaluate the performance of several radiofrequency (RF) management strategies at 10.5T. METHODS Healthy volunteers were imaged on a 10.5T whole-body scanner in multiple target anatomies, including the prostate, hip, kidney, liver, and heart. Phase-only shimming and spoke pulses were used to demonstrate their performance in managing the B 1 + inhomogeneity present at 447 MHz. Imaging protocols included both qualitative and quantitative acquisitions to show the feasibility of imaging with different contrasts. RESULTS High-quality images were acquired and demonstrated excellent overall contrast and signal-to-noise ratio. The experimental results matched well with predictions and suggested good translational capabilities of the RF management strategies previously developed at 7T. Phase-only shimming provided increased efficiency, but showed pronounced limitations in homogeneity, demonstrating the need for the increased degrees of freedom made possible through single- and multispoke RF pulse design. CONCLUSION The first in-vivo human imaging was successfully performed at 10.5T using previously developed RF management strategies. Further improvement in RF coils, transmit chain, and full integration of parallel transmit functionality are needed to fully realize the benefits of 10.5T.
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Affiliation(s)
- Xiaoxuan He
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - M Arcan Ertürk
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Andrea Grant
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Xiaoping Wu
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Russell L Lagore
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Lance DelaBarre
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Yiğitcan Eryaman
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Gregor Adriany
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Eddie J Auerbach
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | | | - Kâmil Uğurbil
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Gregory J Metzger
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
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24
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Jaeschke SHF, Robson MD, Hess AT. Scattering matrix imaging pulse design for real-time respiration and cardiac motion monitoring. Magn Reson Med 2019; 82:2169-2177. [PMID: 31317579 PMCID: PMC6771869 DOI: 10.1002/mrm.27884] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/01/2019] [Accepted: 06/07/2019] [Indexed: 12/26/2022]
Abstract
Purpose The scattering matrix (S‐matrix) of a parallel transmit (pTx) coil is sensitive to physiological motion but requires additional monitoring RF pulses to be measured. In this work, we present and evaluate pTx RF pulse designs that simultaneously excite for imaging and measure the S‐matrix to generate real‐time motion signals without prolonging the image sequence. Theory and Methods Three pTx waveforms for measuring the S‐matrix were identified and superimposed onto the imaging excitation RF pulses: (1) time division multiplexing, (2) frequency division multiplexing, and (3) code division multiplexing. These 3 methods were evaluated in healthy volunteers for scattering sensitivity and image artefacts. The S‐matrix and real‐time motion signals were calculated on the image calculation environment of the MR scanner. Prospective cardiac triggers were identified in early systole as a high rate of change of the cardiac motion signal. Monitoring accuracy was compared against electrocardiogram or the imaged diaphragm position. Results All 3 monitoring approaches measure the S‐matrix during image excitation with quality correlated to input power. No image artefacts were observed for frequency multiplexing, and low energy artefacts were observed in the other methods. The accuracy of the achieved prospective cardiac gating was 15 ± 16 ms for breath hold and 24 ± 17 ms during free breathing. The diaphragm position prediction accuracy was 1.3 ± 0.9 mm. In all volunteers, good quality cine images were acquired for breath hold scans and dual gated CINEs were demonstrated. Conclusion The S‐matrix can be measured during image excitation to generate real‐time cardiac and respiratory motion signals for prospective gating. No artefacts are introduced when frequency division multiplexing is used.
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Affiliation(s)
- Sven H F Jaeschke
- Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Matthew D Robson
- Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,Perspectum Diagnostics, Oxford, United Kingdom
| | - Aaron T Hess
- Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,BHF Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
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25
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Boehmert L, Kuehne A, Waiczies H, Wenz D, Eigentler TW, Funk S, Knobelsdorff‐Brenkenhoff F, Schulz‐Menger J, Nagel AM, Seeliger E, Niendorf T. Cardiorenal sodium MRI at 7.0 Tesla using a 4/4 channel
1
H/
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Na radiofrequency antenna array. Magn Reson Med 2019; 82:2343-2356. [DOI: 10.1002/mrm.27880] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 12/16/2022]
Affiliation(s)
- Laura Boehmert
- Berlin Ultrahigh Field Facility (B.U.F.F.) Max Delbrück Center for Molecular Medicine in the Helmholtz Association Berlin Germany
| | | | | | - Daniel Wenz
- Berlin Ultrahigh Field Facility (B.U.F.F.) Max Delbrück Center for Molecular Medicine in the Helmholtz Association Berlin Germany
| | - Thomas Wilhelm Eigentler
- Berlin Ultrahigh Field Facility (B.U.F.F.) Max Delbrück Center for Molecular Medicine in the Helmholtz Association Berlin Germany
| | - Stephanie Funk
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine Helios Clinics Berlin‐Buch Berlin Germany
| | - Florian Knobelsdorff‐Brenkenhoff
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine Helios Clinics Berlin‐Buch Berlin Germany
- Clinic Agatharied, Dept. of Cardiology Academic Teaching Hospital of the Ludwig‐Maximilians‐University Munich Hausham Germany
| | - Jeanette Schulz‐Menger
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine Helios Clinics Berlin‐Buch Berlin Germany
- DZHK (German Centre for Cardiovascular Research) partner site Berlin Germany
| | - Armin M. Nagel
- Institute of Radiology University Hospital Erlangen, Friedrich‐Alexander‐Universität Erlangen‐Nürnberg (FAU) Erlangen Germany
- Division of Medical Physics in Radiology German Cancer Research Centre (DKFZ) Heidelberg Germany
- Institute of Medical Physics University of Erlangen, Friedrich‐Alexander‐Universität Erlangen‐Nürnberg (FAU) Erlangen Germany
| | - Erdmann Seeliger
- Institute of Vegetative Physiology Charité University Medicine Berlin Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.) Max Delbrück Center for Molecular Medicine in the Helmholtz Association Berlin Germany
- MRI.TOOLS GmbH Berlin Germany
- DZHK (German Centre for Cardiovascular Research) partner site Berlin Germany
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine Berlin Germany
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26
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Erturk MA, Li X, Van de Moortele PF, Ugurbil K, Metzger GJ. Evolution of UHF Body Imaging in the Human Torso at 7T: Technology, Applications, and Future Directions. Top Magn Reson Imaging 2019; 28:101-124. [PMID: 31188271 PMCID: PMC6587233 DOI: 10.1097/rmr.0000000000000202] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
The potential value of ultrahigh field (UHF) magnetic resonance imaging (MRI) and spectroscopy to biomedical research and in clinical applications drives the development of technologies to overcome its many challenges. The increased difficulties of imaging the human torso compared with the head include its overall size, the dimensions and location of its anatomic targets, the increased prevalence and magnitude of physiologic effects, the limited availability of tailored RF coils, and the necessary transmit chain hardware. Tackling these issues involves addressing notoriously inhomogeneous transmit B1 (B1) fields, limitations in peak B1, larger spatial variations of the static magnetic field B0, and patient safety issues related to implants and local RF power deposition. However, as research institutions and vendors continue to innovate, the potential gains are beginning to be realized. Solutions overcoming the unique challenges associated with imaging the human torso are reviewed as are current studies capitalizing on the benefits of UHF in several anatomies and applications. As the field progresses, strategies associated with the RF system architecture, calibration methods, RF pulse optimization, and power monitoring need to be further integrated into the MRI systems making what are currently complex processes more streamlined. Meanwhile, the UHF MRI community must seize the opportunity to build upon what have been so far proof of principle and feasibility studies and begin to further explore the true impact in both research and the clinic.
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Affiliation(s)
- M Arcan Erturk
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN
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27
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Niendorf T, Schulz-Menger J, Paul K, Huelnhagen T, Ferrari VA, Hodge R. High Field Cardiac Magnetic Resonance Imaging: A Case for Ultrahigh Field Cardiac Magnetic Resonance. Circ Cardiovasc Imaging 2019; 10:CIRCIMAGING.116.005460. [PMID: 28611118 DOI: 10.1161/circimaging.116.005460] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Thoralf Niendorf
- From the Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (T.N., K.P., T.H., R.H.); DZHK (German Centre for Cardiovascular Research), partner site Berlin (T.N., J.S.-M.); Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (J.S.-M.); Department for Cardiology and Nephrology, HELIOS Clinic Berlin-Buch, Germany (J.S.-M.); and Division of Cardiovascular Medicine and Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia (V.A.F.).
| | - Jeanette Schulz-Menger
- From the Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (T.N., K.P., T.H., R.H.); DZHK (German Centre for Cardiovascular Research), partner site Berlin (T.N., J.S.-M.); Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (J.S.-M.); Department for Cardiology and Nephrology, HELIOS Clinic Berlin-Buch, Germany (J.S.-M.); and Division of Cardiovascular Medicine and Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia (V.A.F.)
| | - Katharina Paul
- From the Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (T.N., K.P., T.H., R.H.); DZHK (German Centre for Cardiovascular Research), partner site Berlin (T.N., J.S.-M.); Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (J.S.-M.); Department for Cardiology and Nephrology, HELIOS Clinic Berlin-Buch, Germany (J.S.-M.); and Division of Cardiovascular Medicine and Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia (V.A.F.)
| | - Till Huelnhagen
- From the Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (T.N., K.P., T.H., R.H.); DZHK (German Centre for Cardiovascular Research), partner site Berlin (T.N., J.S.-M.); Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (J.S.-M.); Department for Cardiology and Nephrology, HELIOS Clinic Berlin-Buch, Germany (J.S.-M.); and Division of Cardiovascular Medicine and Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia (V.A.F.)
| | - Victor A Ferrari
- From the Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (T.N., K.P., T.H., R.H.); DZHK (German Centre for Cardiovascular Research), partner site Berlin (T.N., J.S.-M.); Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (J.S.-M.); Department for Cardiology and Nephrology, HELIOS Clinic Berlin-Buch, Germany (J.S.-M.); and Division of Cardiovascular Medicine and Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia (V.A.F.)
| | - Russell Hodge
- From the Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (T.N., K.P., T.H., R.H.); DZHK (German Centre for Cardiovascular Research), partner site Berlin (T.N., J.S.-M.); Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (J.S.-M.); Department for Cardiology and Nephrology, HELIOS Clinic Berlin-Buch, Germany (J.S.-M.); and Division of Cardiovascular Medicine and Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia (V.A.F.)
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28
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Lott J, Platt T, Niesporek SC, Paech D, G. R. Behl N, Niendorf T, Bachert P, Ladd ME, Nagel AM. Corrections of myocardial tissue sodium concentration measurements in human cardiac
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Na MRI at 7 Tesla. Magn Reson Med 2019; 82:159-173. [DOI: 10.1002/mrm.27703] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 01/25/2019] [Accepted: 01/31/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Johanna Lott
- German Cancer Research Center (DKFZ), Medical Physics in Radiology Heidelberg Germany
- University of Heidelberg, Faculty of Physics and Astronomy Heidelberg Germany
| | - Tanja Platt
- German Cancer Research Center (DKFZ), Medical Physics in Radiology Heidelberg Germany
| | | | - Daniel Paech
- German Cancer Research Center (DKFZ) Radiology, Heidelberg Germany
| | - Nicolas G. R. Behl
- German Cancer Research Center (DKFZ), Medical Physics in Radiology Heidelberg Germany
| | - Thoralf Niendorf
- Max Delbrueck Center for Molecular Medicine in the Helmholtz Association Berlin Germany
- MRI. TOOLS GmbH Berlin Germany
| | - Peter Bachert
- German Cancer Research Center (DKFZ), Medical Physics in Radiology Heidelberg Germany
- University of Heidelberg, Faculty of Physics and Astronomy Heidelberg Germany
| | - Mark E. Ladd
- German Cancer Research Center (DKFZ), Medical Physics in Radiology Heidelberg Germany
- University of Heidelberg, Faculty of Physics and Astronomy Heidelberg Germany
- University of Heidelberg Faculty of Medicine Heidelberg Germany
| | - Armin M. Nagel
- German Cancer Research Center (DKFZ), Medical Physics in Radiology Heidelberg Germany
- Friedrich‐Alexander‐Universität Erlangen‐Nürnberg (FAU), University Hospital Erlangen Institute of Radiology Erlangen Germany
- Friedrich‐Alexander‐Universität Erlangen‐Nürnberg (FAU) Institute of Medical Physics Erlangen Germany
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29
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Nedoma J, Fajkus M, Martinek R, Nazeran H. Vital Sign Monitoring and Cardiac Triggering at 1.5 Tesla: A Practical Solution by an MR-Ballistocardiography Fiber-Optic Sensor. SENSORS 2019; 19:s19030470. [PMID: 30682784 PMCID: PMC6386836 DOI: 10.3390/s19030470] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/11/2019] [Accepted: 01/21/2019] [Indexed: 12/21/2022]
Abstract
This article presents a solution for continuous monitoring of both respiratory rate (RR) and heart rate (HR) inside Magnetic Resonance Imaging (MRI) environments by a novel ballistocardiography (BCG) fiber-optic sensor. We designed and created a sensor based on the Fiber Bragg Grating (FBG) probe encapsulated inside fiberglass (fiberglass is a composite material made up of glass fiber, fabric, and cured synthetic resin). Due to this, the encapsulation sensor is characterized by very small dimensions (30 × 10 × 0.8 mm) and low weight (2 g). We present original results of real MRI measurements (conventionally most used 1.5 T MR scanner) involving ten volunteers (six men and four women) by performing conventional electrocardiography (ECG) to measure the HR and using a Pneumatic Respiratory Transducer (PRT) for RR monitoring. The acquired sensor data were compared against real measurements using the objective Bland–Altman method, and the functionality of the sensor was validated (95.36% of the sensed values were within the ±1.96 SD range for the RR determination and 95.13% of the values were within the ±1.96 SD range for the HR determination) by this means. The accuracy of this sensor was further characterized by a relative error below 5% (4.64% for RR and 4.87% for HR measurements). The tests carried out in an MRI environment demonstrated that the presence of the FBG sensor in the MRI scanner does not affect the quality of this imaging modality. The results also confirmed the possibility of using the sensor for cardiac triggering at 1.5 T (for synchronization and gating of cardiovascular magnetic resonance) and for cardiac triggering when a Diffusion Weighted Imaging (DWI) is used.
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Affiliation(s)
- Jan Nedoma
- Department of Telecommunications, Faculty of Electrical Engineering and Computer Science, VSB-Technical University of Ostrava, 17 Listopadu 15, 70833 Ostrava, Czech Republic.
| | - Marcel Fajkus
- Department of Telecommunications, Faculty of Electrical Engineering and Computer Science, VSB-Technical University of Ostrava, 17 Listopadu 15, 70833 Ostrava, Czech Republic.
| | - Radek Martinek
- Department of Cybernetics and Biomedical Engineering, Faculty of Electrical Engineering and Computer Science, VSB-Technical University of Ostrava, 17 Listopadu 15, 70833 Ostrava, Czech Republic.
| | - Homer Nazeran
- Department of Metallurgical, Materials and Biomedical Engineering, University of Texas El Paso, 500 W University Ave, El Paso, TX 79968, USA.
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30
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Ladd ME, Bachert P, Meyerspeer M, Moser E, Nagel AM, Norris DG, Schmitter S, Speck O, Straub S, Zaiss M. Pros and cons of ultra-high-field MRI/MRS for human application. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:1-50. [PMID: 30527132 DOI: 10.1016/j.pnmrs.2018.06.001] [Citation(s) in RCA: 250] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 06/06/2018] [Accepted: 06/07/2018] [Indexed: 05/08/2023]
Abstract
Magnetic resonance imaging and spectroscopic techniques are widely used in humans both for clinical diagnostic applications and in basic research areas such as cognitive neuroimaging. In recent years, new human MR systems have become available operating at static magnetic fields of 7 T or higher (≥300 MHz proton frequency). Imaging human-sized objects at such high frequencies presents several challenges including non-uniform radiofrequency fields, enhanced susceptibility artifacts, and higher radiofrequency energy deposition in the tissue. On the other side of the scale are gains in signal-to-noise or contrast-to-noise ratio that allow finer structures to be visualized and smaller physiological effects to be detected. This review presents an overview of some of the latest methodological developments in human ultra-high field MRI/MRS as well as associated clinical and scientific applications. Emphasis is given to techniques that particularly benefit from the changing physical characteristics at high magnetic fields, including susceptibility-weighted imaging and phase-contrast techniques, imaging with X-nuclei, MR spectroscopy, CEST imaging, as well as functional MRI. In addition, more general methodological developments such as parallel transmission and motion correction will be discussed that are required to leverage the full potential of higher magnetic fields, and an overview of relevant physiological considerations of human high magnetic field exposure is provided.
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Affiliation(s)
- Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany; Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Peter Bachert
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany.
| | - Martin Meyerspeer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
| | - Armin M Nagel
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - David G Norris
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands; Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Sebastian Schmitter
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany.
| | - Oliver Speck
- Department of Biomedical Magnetic Resonance, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany; German Center for Neurodegenerative Diseases, Magdeburg, Germany; Center for Behavioural Brain Sciences, Magdeburg, Germany; Leibniz Institute for Neurobiology, Magdeburg, Germany.
| | - Sina Straub
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Moritz Zaiss
- High-Field Magnetic Resonance Center, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany.
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Goebel J, Nensa F, Schemuth HP, Maderwald S, Schlosser T, Orzada S, Rietsch S, Quick HH, Nassenstein K. Feasibility of aortic valve planimetry at 7 T ultrahigh field MRI: Comparison to aortic valve MRI at 3 T and 1.5 T. Eur J Radiol Open 2018; 5:159-164. [PMID: 30225274 PMCID: PMC6138940 DOI: 10.1016/j.ejro.2018.08.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 08/27/2018] [Accepted: 08/27/2018] [Indexed: 11/29/2022] Open
Abstract
Introduction This study examined the feasibility of aortic valve planimetry at 7 T ultrahigh field MRI in intraindividual comparison to 3 T and 1.5 T MRI. Material and methods Aortic valves of eleven healthy volunteers (mean age, 26.4 years) were examined on a 7 T, 3 T, and 1.5 T MR system using FLASH and TrueFISP sequences. Two experienced radiologists evaluated overall image quality, the presence of artefacts, tissue contrast ratios, identifiability, and image details of the aortic valve opening area (AVOA). Furthermore, AVOA was quantified twice by reader 1 and once by reader 2. Correlation analysis between artefact severity and employed magnetic field strength was performed by modified Fisher’s exact-test. Paired t-test was used to analyse for AVOA differences, and Bland-Altman plots were used to analyse AVOA intra-rater and inter-rater variability. Results Aortic valve imaging at 7 T, 3 T, and 1.5 T with using FLASH was less hampered by artefacts than TrueFISP imaging at 3 T and 1.5 T. Tissue contrast and image details were rated best at 7 T. AVOA was measured slightly smaller at 7 T compared to 3 T (TrueFISP, p-value = 0.057; FLASH, p-value = 0.016) and 1.5 T (TrueFISP, p-value = 0.029; FLASH, p-value = 0.018). Intra-rater and inter-rater variability of AVOA tended to be slightly smaller at 7 T than at 3 T and 1.5 T. Conclusion Aortic valve planimetry at 7 T ultrahigh field MRI is technically feasible and in healthy volunteers offers an improved tissue contrast and a slightly better reproducibility than MR planimetry at 1.5 T and 3 T.
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Affiliation(s)
- Juliane Goebel
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - Felix Nensa
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - Haemi P Schemuth
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - Stefan Maderwald
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University of Duisburg-Essen, Essen, Germany
| | - Thomas Schlosser
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - Stephan Orzada
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University of Duisburg-Essen, Essen, Germany
| | - Stefan Rietsch
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University of Duisburg-Essen, Essen, Germany
| | - Harald H Quick
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University of Duisburg-Essen, Essen, Germany.,High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany
| | - Kai Nassenstein
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
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Antoni ST, Lehmann S, Neidhardt M, Fehrs K, Ruprecht C, Kording F, Adam G, Schupp S, Schlaefer A. Model checking for trigger loss detection during Doppler ultrasound-guided fetal cardiovascular MRI. Int J Comput Assist Radiol Surg 2018; 13:1755-1766. [PMID: 30078152 DOI: 10.1007/s11548-018-1832-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 07/25/2018] [Indexed: 11/26/2022]
Abstract
PURPOSE Ultrasound (US) is the state of the art in prenatal diagnosis to depict fetal heart diseases. Cardiovascular magnetic resonance imaging (CMRI) has been proposed as a complementary diagnostic tool. Currently, only trigger-based methods allow the temporal and spatial resolutions necessary to depict the heart over time. Of these methods, only Doppler US (DUS)-based triggering is usable with higher field strengths. DUS is sensitive to motion. This may lead to signal and, ultimately, trigger loss. If too many triggers are lost, the image acquisition is stopped, resulting in a failed imaging sequence. Moreover, losing triggers may prolong image acquisition. Hence, if no actual trigger can be found, injected triggers are added to the signal based on the trigger history. METHOD We use model checking, a technique originating from the computer science domain that formally checks if a model satisfies given requirements, to simultaneously model heart and respiratory motion and to decide whether respiration has a prominent effect on the signal. Using bounds on the physiological parameters and their variability, the method detects when changes in the signal are due to respiration. We use this to decide when to inject a trigger. RESULTS In a real-world scenario, we can reduce the number of falsely injected triggers by 94% from more than 87% to less than 5%. On a subset of motion that would allow CMRI, the number can be further reduced to below 0.2%. In a study using simulations with a robot, we show that our method works for different types of motions, motion ranges, starting positions and heartbeat traces. CONCLUSION While DUS is a promising approach for fetal CMRI, correct trigger injection is critical. Our model checking method can reduce the number of wrongly injected triggers substantially, providing a key prerequisite for fast and artifact free CMRI.
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Affiliation(s)
- Sven-Thomas Antoni
- Institute of Medical Technology, Hamburg University of Technology, Hamburg, Germany.
| | - Sascha Lehmann
- Institute for Software Systems, Hamburg University of Technology, Hamburg, Germany
| | - Maximilian Neidhardt
- Institute of Medical Technology, Hamburg University of Technology, Hamburg, Germany
| | - Kai Fehrs
- Center for Radiology and Endoscopy, Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Ruprecht
- Center for Radiology and Endoscopy, Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Fabian Kording
- Center for Radiology and Endoscopy, Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Gerhard Adam
- Center for Radiology and Endoscopy, Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sibylle Schupp
- Institute for Software Systems, Hamburg University of Technology, Hamburg, Germany
| | - Alexander Schlaefer
- Institute of Medical Technology, Hamburg University of Technology, Hamburg, Germany
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Jaeschke SH, Robson MD, Hess AT. Cardiac gating using scattering of an 8-channel parallel transmit coil at 7T. Magn Reson Med 2018; 80:633-640. [PMID: 29230860 PMCID: PMC5947608 DOI: 10.1002/mrm.27038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 10/27/2017] [Accepted: 11/17/2017] [Indexed: 12/24/2022]
Abstract
PURPOSE To establish a cardiac signal from scattering matrix or scattering coefficient measurements made on a 7T 8-channel parallel transmit (pTx) system, and to evaluate its use for cardiac gating. METHODS Measurements of the scattering matrix and scattering coefficients were acquired using a monitoring pulse sequence and during a standard cine acquisition, respectively. Postprocessing used an independent component analysis and gating feature identification. The effect of the phase of the excitation radiofrequency (RF) field ( B1+ shim) on the cardiac signal was simulated for multiple B1+ shim configurations, and cine images were reconstructed from both the scattering coefficients and electrocardiogram (ECG). RESULTS The cardiac motion signal was successfully identified in all subjects with a mean signal-to-noise ratio of 33.1 and 5.7 using the scattering matrix and scattering coefficient measurements, respectively. The dominant gating feature in the cardiac signal was a peak aligned with end-systole that occurred on average at 311 and 391 ms after the ECG trigger, with a mean standard deviation of 13.4 and 18.1 ms relative to ECG when using the scattering matrix and scattering coefficients measurements, respectively. The scattering coefficients showed a dependence on B1+ shim with some shim configurations not showing any cardiac signal. Cine images were successfully reconstructed using the scattering coefficients with minimal differences compared to those using ECG. CONCLUSION We have shown that the scattering of a pTx RF coil can be used to estimate a cardiac signal, and that scattering matrix and coefficients can be used to cardiac gate MRI acquisitions with the scattering matrix providing a superior cardiac signal. Magn Reson Med 80:633-640, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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Affiliation(s)
- Sven H.F. Jaeschke
- University of Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe HospitalOxfordUnited Kingdom
| | - Matthew D. Robson
- University of Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe HospitalOxfordUnited Kingdom
| | - Aaron T. Hess
- University of Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe HospitalOxfordUnited Kingdom
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Huelnhagen T, Ku MC, Reimann HM, Serradas Duarte T, Pohlmann A, Flemming B, Seeliger E, Eichhorn C, A Ferrari V, Prothmann M, Schulz-Menger J, Niendorf T. Myocardial Effective Transverse Relaxation Time T 2* is Elevated in Hypertrophic Cardiomyopathy: A 7.0 T Magnetic Resonance Imaging Study. Sci Rep 2018; 8:3974. [PMID: 29507338 PMCID: PMC5838254 DOI: 10.1038/s41598-018-22439-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 02/19/2018] [Indexed: 12/18/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common genetic disease of the myocardium and bares the risk of progression to heart failure or sudden cardiac death. Identifying patients at risk remains an unmet need. Recognizing the dependence of microscopic susceptibility on tissue microstructure and on cardiac macromorphology we hypothesized that myocardial T2* might be altered in HCM patients compared to healthy controls. To test this hypothesis, myocardial T2*-mapping was conducted at 7.0 Tesla to enhance T2*-contrast. 2D CINE T2*-mapping was performed in healthy controls and HCM patients. To ensure that T2* is not dominated by macroscopic magnetic field inhomogeneities, volume selective B0 shimming was applied. T2* changes in the interventricular septum across the cardiac cycle were analyzed together with left ventricular radius and ventricular septal wall thickness. The results show that myocardial T2* is elevated throughout the cardiac cycle in HCM patients compared to healthy controls. A mean septal T2* = 13.7 ± 1.1 ms (end-systole: T2*,systole = 15.0 ± 2.1, end-diastole: T2*,diastole = 13.4 ± 1.3 ms, T2*,systole/T2*,diastole ratio = 1.12) was observed in healthy controls. For HCM patients a mean septal T2* = 17.4 ± 1.4 ms (end-systole: T2*,systole = 17.7 ± 1.2 ms, end-diastole: T2*,diastole = 16.2 ± 2.5 ms, T2*,systole/T2*,diastole ratio = 1.09) was found. Our preliminary results provide encouragement that assessment of T2* and its changes across the cardiac cycle may benefit myocardial tissue characterization in HCM.
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Affiliation(s)
- Till Huelnhagen
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Min-Chi Ku
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site, Berlin, Germany
| | - Henning Matthias Reimann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Teresa Serradas Duarte
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Andreas Pohlmann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Bert Flemming
- Institute of Vegetative Physiology, Charité University Medicine, Berlin, Germany
| | - Erdmann Seeliger
- Institute of Vegetative Physiology, Charité University Medicine, Berlin, Germany
| | - Christina Eichhorn
- Statistical Sciences, Department of Information Technology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Victor A Ferrari
- Division of Cardiovascular Medicine and Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
| | - Marcel Prothmann
- DZHK (German Centre for Cardiovascular Research), partner site, Berlin, Germany
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Jeanette Schulz-Menger
- DZHK (German Centre for Cardiovascular Research), partner site, Berlin, Germany
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.
- DZHK (German Centre for Cardiovascular Research), partner site, Berlin, Germany.
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany.
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Kording F, Schoennagel BP, de Sousa MT, Fehrs K, Adam G, Yamamura J, Ruprecht C. Evaluation of a Portable Doppler Ultrasound Gating Device for Fetal Cardiac MR Imaging: Initial Results at 1.5T and 3T. Magn Reson Med Sci 2018; 17:308-317. [PMID: 29467359 PMCID: PMC6196307 DOI: 10.2463/mrms.mp.2017-0100] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Purpose: Fetal cardiac MRI has the potential to play an important role in the assessment of fetal cardiac pathologies, but it is up to now not feasible due to a missing gating method. The purpose of this work was the evaluation of Doppler ultrasound (DUS) for external fetal cardiac gating with regard to compatibility, functionality, and reliability. Preliminary results were assessed performing fetal cardiac MRI. Methods: An MRI conditional DUS device was developed to obtain a gating signal from the fetal heart. The MRI compatibility was evaluated at 1.5T and 3T using B1 field maps and gradient echo images. The quality and sensitivity of the DUS device to detect the fetal heart motion for cardiac gating were evaluated outside the MRI room in 15 fetuses. A dynamic fetal cardiac phantom was employed to evaluate distortions of the DUS device and gating signal due to electromagnetic interferences at 1.5T and 3T. In the first in vivo experience, dynamic fetal cardiac images were acquired in four-chamber view at 1.5T and 3T in two fetuses. Results: The maximum change in the B1 field and signal intensity with and without the DUS device was <6.5% for 1.5T and 3T. The sensitivity of the DUS device to detect the fetal heartbeat was 99.1%. Validation of the DUS device using the fetal cardiac phantom revealed no electromagnetic interferences at 1.5T or 3T and a high correlation to the simulated heart frequencies. Fetal cardiac cine images were successfully applied and showed good image quality. Conclusion: An MR conditional DUS gating device was developed and evaluated revealing safety, compatibility, and reliability for different field strengths. In a preliminary experience, the DUS device was successfully applied for in vivo fetal cardiac imaging at 1.5T and 3T.
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Affiliation(s)
- Fabian Kording
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf.,northh medical GmbH
| | - Bjoern P Schoennagel
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf
| | | | - Kai Fehrs
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf.,northh medical GmbH
| | - Gerhard Adam
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf
| | - Jin Yamamura
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf
| | - Christian Ruprecht
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf.,northh medical GmbH
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Kording F, Ruprecht C, Schoennagel B, Fehrs K, Yamamura J, Adam G, Goebel J, Nassenstein K, Maderwald S, Quick H, Kraff O. Doppler ultrasound triggering for cardiac MRI at 7T. Magn Reson Med 2017; 80:239-247. [DOI: 10.1002/mrm.27032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 10/09/2017] [Accepted: 11/13/2017] [Indexed: 01/31/2023]
Affiliation(s)
- F. Kording
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine; University Medical Center Hamburg-Eppendorf; Hamburg Germany
| | - C. Ruprecht
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine; University Medical Center Hamburg-Eppendorf; Hamburg Germany
| | - B. Schoennagel
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine; University Medical Center Hamburg-Eppendorf; Hamburg Germany
| | - K. Fehrs
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine; University Medical Center Hamburg-Eppendorf; Hamburg Germany
| | - J. Yamamura
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine; University Medical Center Hamburg-Eppendorf; Hamburg Germany
| | - G. Adam
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine; University Medical Center Hamburg-Eppendorf; Hamburg Germany
| | - J. Goebel
- Erwin L. Hahn Institute for Magnetic Resonance Imaging; University Duisburg-Essen; Essen Germany
- Department of Diagnostic and Interventional Radiology and Neuroradiology; University Hospital, University Duisburg-Essen; Essen Germany
| | - K. Nassenstein
- Department of Diagnostic and Interventional Radiology and Neuroradiology; University Hospital, University Duisburg-Essen; Essen Germany
| | - S. Maderwald
- Erwin L. Hahn Institute for Magnetic Resonance Imaging; University Duisburg-Essen; Essen Germany
| | - H.H. Quick
- Erwin L. Hahn Institute for Magnetic Resonance Imaging; University Duisburg-Essen; Essen Germany
- High Field and Hybrid MR Imaging; University Hospital, University Duisburg-Essen; Essen Germany
| | - O. Kraff
- Erwin L. Hahn Institute for Magnetic Resonance Imaging; University Duisburg-Essen; Essen Germany
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Crowe LA, Manasseh G, Chmielewski A, Hachulla AL, Speicher D, Greiser A, Muller H, de Perrot T, Vallee JP, Salomir R. Spatially Resolved MR-Compatible Doppler Ultrasound: Proof of Concept for Triggering of Diagnostic Quality Cardiovascular MRI for Function and Flow Quantification at 3T. IEEE Trans Biomed Eng 2017; 65:294-306. [PMID: 29053451 DOI: 10.1109/tbme.2017.2764111] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE We demonstrate the use of a magnetic-resonance (MR)-compatible ultrasound (US) imaging probe using spatially resolved Doppler for diagnostic quality cardiovascular MR imaging (MRI) as an initial step toward hybrid US/MR fetal imaging. METHODS A newly developed technology for a dedicated MR-compatible phased array ultrasound-imaging probe acquired pulsed color Doppler carotid images, which were converted in near-real time to a trigger signal for cardiac cine and flow quantification MRI. Ultrasound and MR data acquired simultaneously were interference free. Conventional electrocardiogram (ECG) and the proposed spatially resolved Doppler triggering were compared in 10 healthy volunteers. A synthetic "false-triggered" image was retrospectively processed using metric optimized gating (MOG). Images were scored by expert readers, and sharpness, cardiac function and aortic flow were quantified. Four-dimensional (4-D) flow (two volunteers) showed feasibility of Doppler triggering over a long acquisition time. RESULTS Imaging modalities were compatible. US probe positioning was stable and comfortable. Image quality scores and quantified sharpness were statistically equal for Doppler- and ECG-triggering (p ). ECG-, Doppler-triggered, and MOG ejection fractions were equivalent (p ), with false-triggered values significantly lower (p < 0.0005). Aortic flow showed no difference between ECG- and Doppler-triggered and MOG (p > 0.05). 4-D flow quantification gave consistent results between ECG and Doppler triggering. CONCLUSION We report interference-free pulsed color Doppler ultrasound during MR data acquisition. Cardiovascular MRI of diagnostic quality was successfully obtained with pulsed color Doppler triggering. SIGNIFICANCE The hardware platform could further enable advanced free-breathing cardiac imaging. Doppler ultrasound triggering is applicable where ECG is compromised due to pathology or interference at higher magnetic fields, and where direct ECG is impossible, i.e., fetal imaging.
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Kraff O, Quick HH. 7T: Physics, safety, and potential clinical applications. J Magn Reson Imaging 2017; 46:1573-1589. [DOI: 10.1002/jmri.25723] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 03/17/2017] [Indexed: 12/19/2022] Open
Affiliation(s)
- Oliver Kraff
- Erwin L. Hahn Institute for MR Imaging; University of Duisburg-Essen; Essen Germany
| | - Harald H. Quick
- Erwin L. Hahn Institute for MR Imaging; University of Duisburg-Essen; Essen Germany
- High Field and Hybrid MR Imaging; University Hospital Essen; Essen Germany
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Valkovič L, Clarke WT, Purvis LA, Schaller B, Robson MD, Rodgers CT. Adiabatic excitation for 31 P MR spectroscopy in the human heart at 7 T: A feasibility study. Magn Reson Med 2016; 78:1667-1673. [PMID: 28000961 PMCID: PMC5645675 DOI: 10.1002/mrm.26576] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 11/16/2016] [Accepted: 11/18/2016] [Indexed: 11/18/2022]
Abstract
Purpose Phosphorus magnetic resonance spectroscopy (31P‐MRS) provides a unique tool for assessing cardiac energy metabolism, often quantified using the phosphocreatine (PCr)/adenosine triphosphate (ATP) ratio. Surface coils are typically used for excitation for 31P‐MRS, but they create an inhomogeneous excitation field across the myocardium, producing undesirable, spatially varying partial saturation. Therefore, we implemented adiabatic excitation in a 3D chemical shift imaging (CSI) sequence for cardiac 31P‐MRS at 7 Tesla (T). Methods We optimized an adiabatic half passage pulse with bandwidth sufficient to excite PCr and γ‐ATP together. In addition, the CSI sequence was modified to allow interleaved excitation of PCr and γ‐ATP, then 2,3‐DPG, to enable PCr/ATP determination with blood correction. Nine volunteers were scanned at 2 transmit voltages to confirm that measured PCr/ATP was independent of
B1+ (i.e. over the adiabatic threshold). Six septal voxels were evaluated for each volunteer. Results Phantom experiments showed that adiabatic excitation can be reached at the depth of the heart using our pulse. The mean evaluated cardiac PCr/ATP ratio from all 9 volunteers corrected for blood signal was 2.14 ± 0.16. Comparing the two acquisitions with different voltages resulted in a minimal mean difference of
−0.005. Conclusion Adiabatic excitation is possible in the human heart at 7 T, and gives consistent PCr/ATP ratios. Magn Reson Med 78:1667–1673, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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Affiliation(s)
- Ladislav Valkovič
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUnited Kingdom
- Department of Imaging MethodsInstitute of Measurement Science, Slovak Academy of SciencesBratislavaSlovakia
| | - William T. Clarke
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUnited Kingdom
| | - Lucian A.B. Purvis
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUnited Kingdom
| | - Benoit Schaller
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUnited Kingdom
| | - Matthew D. Robson
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUnited Kingdom
| | - Christopher T. Rodgers
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUnited Kingdom
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Spicher N, Kukuk M, Maderwald S, Ladd ME. Initial evaluation of prospective cardiac triggering using photoplethysmography signals recorded with a video camera compared to pulse oximetry and electrocardiography at 7T MRI. Biomed Eng Online 2016; 15:126. [PMID: 27881126 PMCID: PMC5122166 DOI: 10.1186/s12938-016-0245-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 11/10/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Accurate synchronization between magnetic resonance imaging data acquisition and a subject's cardiac activity ("triggering") is essential for reducing image artifacts but conventional, contact-based methods for this task are limited by several factors, including preparation time, patient inconvenience, and susceptibility to signal degradation. The purpose of this work is to evaluate the performance of a new contact-free triggering method developed with the aim to eventually replace conventional methods in non-cardiac imaging applications. In this study, the method's performance is evaluated in the context of 7 Tesla non-enhanced angiography of the lower extremities. METHODS Our main contribution is a basic algorithm capable of estimating in real-time the phase of the cardiac cycle from reflection photoplethysmography signals obtained from skin color variations of the forehead recorded with a video camera. Instead of finding the algorithm's parameters heuristically, they were optimized using videos of the forehead as well as electrocardiography and pulse oximetry signals that were recorded from eight healthy volunteers in and outside the scanner, with and without active radio frequency and gradient coils. Based on the video characteristics, synthetic signals were generated and the "best available" values of an objective function were determined using mathematical optimization. The performance of the proposed method with optimized algorithm parameters was evaluated by applying it to the recorded videos and comparing the computed triggers to those of contact-based methods. Additionally, the method was evaluated by using its triggers for acquiring images from a healthy volunteer and comparing the result to images obtained using pulse oximetry triggering. RESULTS During evaluation of the videos recorded inside the bore with active radio frequency and gradient coils, the pulse oximeter triggers were labeled in 62.5% as "potentially usable" for cardiac triggering, the electrocardiography triggers in 12.5%, and the proposed method's triggers in 62.5%. Evaluation of the angiography images demonstrated that under appropriate conditions the method is feasible to produce an image quality comparable to pulse oximetry. CONCLUSION We conclude that cardiac triggering using the proposed method is technically feasible. However, for improved reliability the signal-to-noise ratio of the videos will have to be addressed by either replacing the camera sensor, improving the illumination, or by use of additional signal filtering techniques.
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Affiliation(s)
- Nicolai Spicher
- Department of Computer Science, University of Applied Sciences and Arts Dortmund, Emil-Figge-Str. 42, 44227, Dortmund, Germany.
| | - Markus Kukuk
- Department of Computer Science, University of Applied Sciences and Arts Dortmund, Emil-Figge-Str. 42, 44227, Dortmund, Germany
| | - Stefan Maderwald
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Kokereiallee 7, 45141, Essen, Germany
| | - Mark E Ladd
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Kokereiallee 7, 45141, Essen, Germany.,Division of Medical Physics in Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
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Stoll VM, Clarke WT, Levelt E, Liu A, Myerson SG, Robson MD, Neubauer S, Rodgers CT. Dilated Cardiomyopathy: Phosphorus 31 MR Spectroscopy at 7 T. Radiology 2016. [PMID: 27326664 DOI: 10.1148/radiol.2016152629:152629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Purpose To test whether the increased signal-to-noise ratio of phosphorus 31 (31P) magnetic resonance (MR) spectroscopy at 7 T improves precision in cardiac metabolite quantification in patients with dilated cardiomyopathy (DCM) compared with that at 3 T. Materials and Methods Ethical approval was obtained, and participants provided written informe consent. In a prospective study, 31P MR spectroscopy was performed at 3 T and 7 T in 25 patients with DCM. Ten healthy matched control subjects underwent 31P MR spectroscopy at 7 T. Paired Student t tests were performed to compare results between the 3-T and 7-T studies. Results The phosphocreatine (PCr) signal-to-noise ratio increased 2.5 times at 7 T compared with that at 3 T. The PCr to adenosine triphosphate (ATP) concentration ratio (PCr/ATP) was similar at both field strengths (mean ± standard deviation, 1.48 ± 0.44 at 3 T vs 1.54 ± 0.39 at 7 T, P = .49), as expected. The Cramér-Rao lower bounds in PCr concentration (a measure of uncertainty in the measured ratio) were 45% lower at 7 T than at 3 T, reflecting the higher quality of 7-T 31P spectra. Patients with dilated cardioyopathy had a significantly lower PCr/ATP than did healthy control subjects at 7 T (1.54 ± 0.39 vs 1.95 ± 0.25, P = .005), which is consistent with previous findings. Conclusion 7-T cardiac 31P MR spectroscopy is feasible in patients with DCM and gives higher signal-to-noise ratios and more precise quantification of the PCr/ATP than that at 3 T. PCr/ATP was significantly lower in patients with DCM than in control subjects at 7 T, which is consistent with previous findings at lower field strengths.
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Affiliation(s)
- Victoria M Stoll
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
| | - William T Clarke
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
| | - Eylem Levelt
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
| | - Alexander Liu
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
| | - Saul G Myerson
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
| | - Matthew D Robson
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
| | - Stefan Neubauer
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
| | - Christopher T Rodgers
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
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Weinberger O, Winter L, Dieringer MA, Els A, Oezerdem C, Rieger J, Kuehne A, Cassara AM, Pfeiffer H, Wetterling F, Niendorf T. Local Multi-Channel RF Surface Coil versus Body RF Coil Transmission for Cardiac Magnetic Resonance at 3 Tesla: Which Configuration Is Winning the Game? PLoS One 2016; 11:e0161863. [PMID: 27598923 PMCID: PMC5012568 DOI: 10.1371/journal.pone.0161863] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 07/20/2016] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION The purpose of this study was to demonstrate the feasibility and efficiency of cardiac MR at 3 Tesla using local four-channel RF coil transmission and benchmark it against large volume body RF coil excitation. METHODS Electromagnetic field simulations are conducted to detail RF power deposition, transmission field uniformity and efficiency for local and body RF coil transmission. For both excitation regimes transmission field maps are acquired in a human torso phantom. For each transmission regime flip angle distributions and blood-myocardium contrast are examined in a volunteer study of 12 subjects. The feasibility of the local transceiver RF coil array for cardiac chamber quantification at 3 Tesla is demonstrated. RESULTS Our simulations and experiments demonstrate that cardiac MR at 3 Tesla using four-channel surface RF coil transmission is competitive versus current clinical CMR practice of large volume body RF coil transmission. The efficiency advantage of the 4TX/4RX setup facilitates shorter repetition times governed by local SAR limits versus body RF coil transmission at whole-body SAR limit. No statistically significant difference was found for cardiac chamber quantification derived with body RF coil versus four-channel surface RF coil transmission. Our simulation also show that the body RF coil exceeds local SAR limits by a factor of ~2 when driven at maximum applicable input power to reach the whole-body SAR limit. CONCLUSION Pursuing local surface RF coil arrays for transmission in cardiac MR is a conceptually appealing alternative to body RF coil transmission, especially for patients with implants.
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Affiliation(s)
- Oliver Weinberger
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Lukas Winter
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Matthias A. Dieringer
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Antje Els
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Celal Oezerdem
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- German Centre for Cardiovascular Research (DZHK), Berlin, Germany
| | | | | | - Antonino M. Cassara
- Medical Metrology Department, Physikalisch Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Harald Pfeiffer
- Medical Metrology Department, Physikalisch Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | | | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max Delbrueck Center for Molecular Medicine, Berlin, Germany
- MRI.TOOLS GmbH, Berlin, Germany
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43
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Stäb D, Roessler J, O'Brien K, Hamilton-Craig C, Barth M. ECG Triggering in Ultra-High Field Cardiovascular MRI. ACTA ACUST UNITED AC 2016; 2:167-174. [PMID: 30042961 PMCID: PMC6024401 DOI: 10.18383/j.tom.2016.00193] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Cardiac magnetic resonance imaging at ultra-high field (B0 ≥ 7 T) potentially provides improved resolution and new opportunities for tissue characterization. Although an accurate synchronization of the acquisition to the cardiac cycle is essential, electrocardiogram (ECG) triggering at ultra-high field can be significantly impacted by the magnetohydrodynamic (MHD) effect. Blood flow within a static magnetic field induces a voltage, which superimposes the ECG and often affects the recognition of the R-wave. The MHD effect scales with B0 and is particularly pronounced at ultra-high field creating triggering-related image artifacts. Here, we investigated the performance of a conventional 3-lead ECG trigger device and a state-of-the-art trigger algorithm for cardiac ECG synchronization at 7 T. We show that by appropriate subject preparation and by including a learning phase for the R-wave detection outside of the magnetic field, reliable ECG triggering is feasible in healthy subjects at 7 T without additional equipment. Ultra-high field cardiac imaging was performed with the ECG signal and the trigger events recorded in 8 healthy subjects. Despite severe ECG signal distortions, synchronized imaging was successfully performed. Recorded ECG signals, vectorcardiograms, and large consistency in trigger event spacing indicate high accuracy for R-wave detection.
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Affiliation(s)
- Daniel Stäb
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia.,Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany
| | | | | | - Christian Hamilton-Craig
- Richard Slaughter Centre of Excellence in CVMRI, The Prince Charles Hospital, Brisbane, Queensland, Australia
| | - Markus Barth
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia
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Niendorf T, Paul K, Oezerdem C, Graessl A, Klix S, Huelnhagen T, Hezel F, Rieger J, Waiczies H, Frahm J, Nagel AM, Oberacker E, Winter L. W(h)ither human cardiac and body magnetic resonance at ultrahigh fields? technical advances, practical considerations, applications, and clinical opportunities. NMR IN BIOMEDICINE 2016; 29:1173-97. [PMID: 25706103 DOI: 10.1002/nbm.3268] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 12/26/2014] [Accepted: 01/13/2015] [Indexed: 05/12/2023]
Abstract
The objective of this study was to document and review advances and groundbreaking progress in cardiac and body MR at ultrahigh fields (UHF, B0 ≥ 7.0 T) with the goal to attract talent, clinical adopters, collaborations and resources to the biomedical and diagnostic imaging communities. This review surveys traits, advantages and challenges of cardiac and body MR at 7.0 T. The considerations run the gamut from technical advances to clinical opportunities. Key concepts, emerging technologies, practical considerations, frontier applications and future directions of UHF body and cardiac MR are provided. Examples of UHF cardiac and body imaging strategies are demonstrated. Their added value over the kindred counterparts at lower fields is explored along with an outline of research promises. The achievements of cardiac and body UHF-MR are powerful motivators and enablers, since extra speed, signal and imaging capabilities may be invested to overcome the fundamental constraints that continue to hamper traditional cardiac and body MR applications. If practical obstacles, concomitant physics effects and technical impediments can be overcome in equal measure, sophisticated cardiac and body UHF-MR will help to open the door to new MRI and MRS approaches for basic research and clinical science, with the lessons learned at 7.0 T being transferred into broad clinical use including diagnostics and therapy guiding at lower fields. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Thoralf Niendorf
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site, Berlin, Germany
| | - Katharina Paul
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Celal Oezerdem
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Andreas Graessl
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Sabrina Klix
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Till Huelnhagen
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Fabian Hezel
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | | | | | - Jens Frahm
- Biomedizinische NMR Forschungs GmbH, am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site, Göttingen, Germany
| | - Armin M Nagel
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Eva Oberacker
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Lukas Winter
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
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Huelnhagen T, Hezel F, Serradas Duarte T, Pohlmann A, Oezerdem C, Flemming B, Seeliger E, Prothmann M, Schulz-Menger J, Niendorf T. Myocardial effective transverse relaxation time T2* Correlates with left ventricular wall thickness: A 7.0 T MRI study. Magn Reson Med 2016; 77:2381-2389. [PMID: 27342430 DOI: 10.1002/mrm.26312] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 05/23/2016] [Accepted: 05/25/2016] [Indexed: 12/13/2022]
Abstract
PURPOSE Myocardial effective relaxation time T2* is commonly regarded as a surrogate for myocardial tissue oxygenation. However, it is legitimate to assume that there are multiple factors that influence T2*. To this end, this study investigates the relationship between T2* and cardiac macromorphology given by left ventricular (LV) wall thickness and left ventricular radius, and provides interpretation of the results in the physiological context. METHODS High spatio-temporally resolved myocardial CINE T2* mapping was performed in 10 healthy volunteers using a 7.0 Tesla (T) full-body MRI system. Ventricular septal wall thickness, left ventricular inner radius, and T2* were analyzed. Macroscopic magnetic field changes were elucidated using cardiac phase-resolved magnetic field maps. RESULTS Ventricular septal T2* changes periodically over the cardiac cycle, increasing in systole and decreasing in diastole. Ventricular septal wall thickness and T2* showed a significant positive correlation, whereas the inner LV radius and T2* were negatively correlated. The effect of macroscopic magnetic field gradients on T2* can be considered minor in the ventricular septum. CONCLUSION Our findings suggest that myocardial T2* is related to tissue blood volume fraction. Temporally resolved T2* mapping could be beneficial for myocardial tissue characterization and for understanding cardiac (patho)physiology in vivo. Magn Reson Med 77:2381-2389, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Till Huelnhagen
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Fabian Hezel
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Teresa Serradas Duarte
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Andreas Pohlmann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Celal Oezerdem
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Bert Flemming
- Institute of Physiology, Charité University Medicine, Berlin, Germany
| | - Erdmann Seeliger
- Institute of Physiology, Charité University Medicine, Berlin, Germany
| | - Marcel Prothmann
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine.,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany
| | - Jeanette Schulz-Menger
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine.,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany
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Stoll VM, Clarke WT, Levelt E, Liu A, Myerson SG, Robson MD, Neubauer S, Rodgers CT. Dilated Cardiomyopathy: Phosphorus 31 MR Spectroscopy at 7 T. Radiology 2016; 281:409-417. [PMID: 27326664 PMCID: PMC5084974 DOI: 10.1148/radiol.2016152629] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Cardiac phosphorus spectroscopy is demonstrated to be feasible in patients at 7 T,
giving higher signal-to-noise ratios and more precise quantification of the
phosphocreatine to adenosine triphosphate concentration ratio than at 3 T in a group
of 25 patients with dilated cardiomyopathy. Purpose To test whether the increased signal-to-noise ratio of phosphorus 31
(31P) magnetic resonance (MR) spectroscopy at 7 T improves precision
in cardiac metabolite quantification in patients with dilated cardiomyopathy (DCM)
compared with that at 3 T. Materials and Methods Ethical approval was obtained, and participants provided written informe consent.
In a prospective study, 31P MR spectroscopy was performed at 3 T and 7
T in 25 patients with DCM. Ten healthy matched control subjects underwent
31P MR spectroscopy at 7 T. Paired Student t tests
were performed to compare results between the 3-T and 7-T studies. Results The phosphocreatine (PCr) signal-to-noise ratio increased 2.5 times at 7 T
compared with that at 3 T. The PCr to adenosine triphosphate (ATP) concentration
ratio (PCr/ATP) was similar at both field strengths (mean ± standard
deviation, 1.48 ± 0.44 at 3 T vs 1.54 ± 0.39 at 7 T, P
= .49), as expected. The Cramér-Rao lower bounds in PCr concentration (a
measure of uncertainty in the measured ratio) were 45% lower at 7 T than at 3 T,
reflecting the higher quality of 7-T 31P spectra. Patients with dilated
cardioyopathy had a significantly lower PCr/ATP than did healthy control subjects
at 7 T (1.54 ± 0.39 vs 1.95 ± 0.25, P = .005),
which is consistent with previous findings. Conclusion 7-T cardiac 31P MR spectroscopy is feasible in patients with DCM and
gives higher signal-to-noise ratios and more precise quantification of the PCr/ATP
than that at 3 T. PCr/ATP was significantly lower in patients with DCM than in
control subjects at 7 T, which is consistent with previous findings at lower field
strengths.
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Affiliation(s)
- Victoria M Stoll
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
| | - William T Clarke
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
| | - Eylem Levelt
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
| | - Alexander Liu
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
| | - Saul G Myerson
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
| | - Matthew D Robson
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
| | - Stefan Neubauer
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
| | - Christopher T Rodgers
- From the Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford OX3 9DU, England
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Kording F, Yamamura J, Lund G, Ueberle F, Jung C, Adam G, Schoennagel BP. Doppler Ultrasound Triggering for Cardiovascular MRI at 3T in a Healthy Volunteer Study. Magn Reson Med Sci 2016; 16:98-108. [PMID: 27001390 PMCID: PMC5600068 DOI: 10.2463/mrms.mp.2015-0104] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Purpose: Electrocardiogram (ECG) triggering for cardiac magnetic resonance (CMR) may be influenced by electromagnetic interferences with increasing magnetic field strength. The aim of this study was to evaluate the performance of Doppler ultrasound (DUS) as an alternative trigger technique for CMR in comparison to ECG and pulse oximetry (POX) at 3T and using different sequence types. Methods: Balanced turbo field echo two-dimensional (2D) short axis cine CMR and 2D phase-contrast angiography of the ascending aorta was performed in 11 healthy volunteers at 3T using ECG, DUS, and POX for cardiac triggering. DUS and POX triggering were compared to the reference standard of ECG in terms of trigger quality (trigger detection and temporal variability), image quality [endocardial blurring (EB)], and functional measurements [left ventricular (LV) volumetry and aortic blood flow velocimetry]. Results: Trigger signal detection and temporal variability did not differ significantly between ECG/DUS (I = 0.6) and ECG/POX (P = 0.4). Averaged EB was similar for ECG, DUS, and POX (pECG/DUS = 0.4, pECG/POX = 0.9). Diastolic EB was significantly decreased for DUS in comparison to ECG (P = 0.02) and POX (P = 0.04). The LV function assessment and aortic blood flow were not significantly different. Conclusion: This study demonstrated the feasibility of DUS for gating human CMR at 3T. The magnetohydrodynamic effect did not significantly disturb ECG triggering in this small healthy volunteer study. DUS showed a significant improvement in diastolic EB but could not be identified as a superior trigger method. The potential benefit of DUS has to be evaluated in a larger clinical patient population.
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Affiliation(s)
- Fabian Kording
- University Medical Center Hamburg-Eppendorf, Center for Radiology and Endoscopy, Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf
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Prothmann M, von Knobelsdorff-Brenkenhoff F, Töpper A, Dieringer MA, Shahid E, Graessl A, Rieger J, Lysiak D, Thalhammer C, Huelnhagen T, Kellman P, Niendorf T, Schulz-Menger J. High Spatial Resolution Cardiovascular Magnetic Resonance at 7.0 Tesla in Patients with Hypertrophic Cardiomyopathy - First Experiences: Lesson Learned from 7.0 Tesla. PLoS One 2016; 11:e0148066. [PMID: 26863618 PMCID: PMC4749213 DOI: 10.1371/journal.pone.0148066] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 01/12/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Cardiovascular Magnetic Resonance (CMR) provides valuable information in patients with hypertrophic cardiomyopathy (HCM) based on myocardial tissue differentiation and the detection of small morphological details. CMR at 7.0T improves spatial resolution versus today's clinical protocols. This capability is as yet untapped in HCM patients. We aimed to examine the feasibility of CMR at 7.0T in HCM patients and to demonstrate its capability for the visualization of subtle morphological details. METHODS We screened 131 patients with HCM. 13 patients (9 males, 56 ±31 years) and 13 healthy age- and gender-matched subjects (9 males, 55 ±31years) underwent CMR at 7.0T and 3.0T (Siemens, Erlangen, Germany). For the assessment of cardiac function and morphology, 2D CINE imaging was performed (voxel size at 7.0T: (1.4x1.4x2.5) mm3 and (1.4x1.4x4.0) mm3; at 3.0T: (1.8x1.8x6.0) mm3). Late gadolinium enhancement (LGE) was performed at 3.0T for detection of fibrosis. RESULTS All scans were successful and evaluable. At 3.0T, quantification of the left ventricle (LV) showed similar results in short axis view vs. the biplane approach (LVEDV, LVESV, LVMASS, LVEF) (p = 0.286; p = 0.534; p = 0.155; p = 0.131). The LV-parameters obtained at 7.0T where in accordance with the 3.0T data (pLVEDV = 0.110; pLVESV = 0.091; pLVMASS = 0.131; pLVEF = 0.182). LGE was detectable in 12/13 (92%) of the HCM patients. High spatial resolution CINE imaging at 7.0T revealed hyperintense regions, identifying myocardial crypts in 7/13 (54%) of the HCM patients. All crypts were located in the LGE-positive regions. The crypts were not detectable at 3.0T using a clinical protocol. CONCLUSIONS CMR at 7.0T is feasible in patients with HCM. High spatial resolution gradient echo 2D CINE imaging at 7.0T allowed the detection of subtle morphological details in regions of extended hypertrophy and LGE.
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Affiliation(s)
- Marcel Prothmann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty of the Humboldt University of Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany
| | - Florian von Knobelsdorff-Brenkenhoff
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty of the Humboldt University of Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany
| | - Agnieszka Töpper
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty of the Humboldt University of Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany
| | - Matthias A. Dieringer
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty of the Humboldt University of Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany
| | - Etham Shahid
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty of the Humboldt University of Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany
| | - Andreas Graessl
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | | | - Darius Lysiak
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- MRI.TOOLS GmbH, Berlin, Germany
| | - C. Thalhammer
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Till Huelnhagen
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Peter Kellman
- National Institutes of Health / NHLBI, Bethesda, Maryland, United States of America
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- MRI.TOOLS GmbH, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany
| | - Jeanette Schulz-Menger
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty of the Humboldt University of Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany
- * E-mail:
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Yerly J, Ginami G, Nordio G, Coristine AJ, Coppo S, Monney P, Stuber M. Coronary endothelial function assessment using self-gated cardiac cine MRI andk-tsparse SENSE. Magn Reson Med 2015; 76:1443-1454. [DOI: 10.1002/mrm.26050] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 09/30/2015] [Accepted: 10/23/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Jérôme Yerly
- Department of Radiology; University Hospital and University of Lausanne; Lausanne Switzerland
- Center for Biomedical Imaging; Lausanne Switzerland
| | - Giulia Ginami
- Department of Radiology; University Hospital and University of Lausanne; Lausanne Switzerland
- Center for Biomedical Imaging; Lausanne Switzerland
| | - Giovanna Nordio
- Department of Radiology; University Hospital and University of Lausanne; Lausanne Switzerland
- Center for Biomedical Imaging; Lausanne Switzerland
| | - Andrew J. Coristine
- Department of Radiology; University Hospital and University of Lausanne; Lausanne Switzerland
- Center for Biomedical Imaging; Lausanne Switzerland
| | - Simone Coppo
- Department of Radiology; University Hospital and University of Lausanne; Lausanne Switzerland
- Center for Biomedical Imaging; Lausanne Switzerland
| | - Pierre Monney
- Cardiac MR Center, Service of Cardiology; University Hospital of Lausanne; Lausanne Switzerland
| | - Matthias Stuber
- Department of Radiology; University Hospital and University of Lausanne; Lausanne Switzerland
- Center for Biomedical Imaging; Lausanne Switzerland
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Retrospectively-gated CINE 23Na imaging of the heart at 7.0 Tesla using density-adapted 3D projection reconstruction. Magn Reson Imaging 2015; 33:1091-1097. [DOI: 10.1016/j.mri.2015.06.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 05/28/2015] [Accepted: 06/20/2015] [Indexed: 11/21/2022]
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