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Nohava L, Czerny R, Tik M, Wurzer D, Laistler E, Frass-Kriegl R. Citizen science approach to assessing patient perception of MRI with flexible radiofrequency coils. Sci Rep 2024; 14:2811. [PMID: 38307928 PMCID: PMC10837436 DOI: 10.1038/s41598-024-53364-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 01/30/2024] [Indexed: 02/04/2024] Open
Abstract
Magnetic Resonance Imaging (MRI) is a major medical imaging modality, which is non-invasive and provides unique soft tissue contrast without ionizing radiation. The successful completion of MRI exams critically depends on patient compliance, and, thus patient comfort. The design, appearance and usability of local MRI radiofrequency (RF) coils potentially influences the patients' perception of the exam. However, systematic investigations and empirical evidence for these aspects are missing. A questionnaire specifically evaluating the impact of RF coils on patient comfort in MRI would be a valuable addition to clinical studies comparing the performance of novel flexible RF coils with standard rigid coils. This paper describes the development of such a questionnaire in the scope of a citizen science (CS) initiative conducted with a group of students at the upper secondary school level. In this work, the CS initiative is presented in the format of a case report and its impact on scientific projects and the students' education is outlined. The resulting questionnaire is made available in German and English so as to be directly applicable by researchers working on the clinical evaluation of novel RF coils or the comfort evaluation of specific hardware setups in general.
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Affiliation(s)
- Lena Nohava
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Raphaela Czerny
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Martin Tik
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Dagmar Wurzer
- Bundes(real)gymnasium BG/BRG Keimgasse, Mödling, Austria
| | - Elmar Laistler
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Roberta Frass-Kriegl
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
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Özütemiz C, White M, Elvendahl W, Eryaman Y, Marjańska M, Metzger GJ, Patriat R, Kulesa J, Harel N, Watanabe Y, Grant A, Genovese G, Cayci Z. Use of a Commercial 7-T MRI Scanner for Clinical Brain Imaging: Indications, Protocols, Challenges, and Solutions-A Single-Center Experience. AJR Am J Roentgenol 2023; 221:788-804. [PMID: 37377363 PMCID: PMC10825876 DOI: 10.2214/ajr.23.29342] [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] [Indexed: 06/29/2023]
Abstract
The first commercially available 7-T MRI scanner (Magnetom Terra) was approved by the FDA in 2017 for clinical imaging of the brain and knee. After initial protocol development and sequence optimization efforts in volunteers, the 7-T system, in combination with an FDA-approved 1-channel transmit/32-channel receive array head coil, can now be routinely used for clinical brain MRI examinations. The ultrahigh field strength of 7-T MRI has the advantages of improved spatial resolution, increased SNR, and increased CNR but also introduces an array of new technical challenges. The purpose of this article is to describe an institutional experience with the use of the commercially available 7-T MRI scanner for routine clinical brain imaging. Specific clinical indications for which 7-T MRI may be useful for brain imaging include brain tumor evaluation with possible perfusion imaging and/or spectroscopy, radiotherapy planning; evaluation of multiple sclerosis and other demyelinating diseases, evaluation of Parkinson disease and guidance of deep brain stimulator placement, high-detail intracranial MRA and vessel wall imaging, evaluation of pituitary pathology, and evaluation of epilepsy. Detailed protocols, including sequence parameters, for these various indications are presented, and implementation challenges (including artifacts, safety, and side effects) and potential solutions are explored.
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Affiliation(s)
- Can Özütemiz
- Department of Radiology, University of Minnesota, 420 Delaware St SE, MMC 292, Minneapolis, MN 55455
| | - Matthew White
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN
- Center for Clinical Imaging Research, Department of Radiology, University of Minnesota, Minneapolis, MN
| | - Wendy Elvendahl
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN
- Center for Clinical Imaging Research, Department of Radiology, University of Minnesota, Minneapolis, MN
| | - Yigitcan Eryaman
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN
| | - Małgorzata Marjańska
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN
| | - Gregory J Metzger
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN
| | - Rémi Patriat
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN
| | - Jeramy Kulesa
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN
| | - Noam Harel
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN
| | - Yoichi Watanabe
- Department of Radiation Oncology, University of Minnesota, Minneapolis, MN
| | - Andrea Grant
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN
| | - Guglielmo Genovese
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN
| | - Zuzan Cayci
- Department of Radiology, University of Minnesota, 420 Delaware St SE, MMC 292, Minneapolis, MN 55455
- Center for Clinical Imaging Research, Department of Radiology, University of Minnesota, Minneapolis, MN
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Pogson JM, Shemesh A, Roberts DC, Zee DS, Otero-Milan J, Ward BK. Longer duration entry mitigates nystagmus and vertigo in 7-Tesla MRI. Front Neurol 2023; 14:1255105. [PMID: 38046576 PMCID: PMC10690370 DOI: 10.3389/fneur.2023.1255105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Accepted: 10/10/2023] [Indexed: 12/05/2023] Open
Abstract
Introduction Patients and technologists commonly describe vertigo, dizziness, and imbalance near high-field magnets, e.g., 7-Tesla (T) magnetic resonance imaging (MRI) scanners. We sought a simple way to alleviate vertigo and dizziness in high-field MRI scanners by applying the understanding of the mechanisms behind magnetic vestibular stimulation and the innate characteristics of vestibular adaptation. Methods We first created a three-dimensional (3D) control systems model of the direct and indirect vestibulo-ocular reflex (VOR) pathways, including adaptation mechanisms. The goal was to develop a paradigm for human participants undergoing a 7T MRI scan to optimize the speed and acceleration of entry into and exit from the MRI bore to minimize unwanted vertigo. We then applied this paradigm from the model by recording 3D binocular eye movements (horizontal, vertical, and torsion) and the subjective experience of eight normal individuals within a 7T MRI. The independent variables were the duration of entry into and exit from the MRI bore, the time inside the MRI bore, and the magnetic field strength; the dependent variables were nystagmus slow-phase eye velocity (SPV) and the sensation of vertigo. Results In the model, when the participant was exposed to a linearly increasing magnetic field strength, the per-peak (after entry into the MRI bore) and post-peak (after exiting the MRI bore) responses of nystagmus SPV were reduced with increasing duration of entry and exit, respectively. There was a greater effect on the per-peak response. The entry/exit duration and peak response were inversely related, and the nystagmus was decreased the most with the 5-min duration paradigm (the longest duration modeled). The experimental nystagmus pattern of the eight normal participants matched the model, with increasing entry duration having the strongest effect on the per-peak response of nystagmus SPV. Similarly, all participants described less vertigo with the longer duration entries. Conclusion Increasing the duration of entry into and exit out of a 7T MRI scanner reduced or eliminated vertigo symptoms and reduced nystagmus peak SPV. Model simulations suggest that central processes of vestibular adaptation account for these effects. Therefore, 2-min entry and 20-s exit durations are a practical solution to mitigate vertigo and other discomforting symptoms associated with undergoing 7T MRI scans. In principle, these findings also apply to different magnet strengths.
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Affiliation(s)
- Jacob M. Pogson
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Neurology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
| | - Ari Shemesh
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, Berkeley, CA, United States
| | - Dale C. Roberts
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Neuroscience, The Johns Hopkins University, Baltimore, MD, United States
| | - David S. Zee
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Neuroscience, The Johns Hopkins University, Baltimore, MD, United States
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Wilmer Eye Institute, The Johns Hopkins University, Baltimore, MD, United States
| | - Jorge Otero-Milan
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, Berkeley, CA, United States
| | - Bryan K. Ward
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
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4
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Cudalbu C, Xin L, Marechal B, Lachat S, Zangas-Gheri F, Valenza N, Hanquinet S, McLin VA. High field brain proton magnetic resonance spectroscopy and volumetry in children with chronic, compensated liver disease - A pilot study. Anal Biochem 2023:115212. [PMID: 37356555 DOI: 10.1016/j.ab.2023.115212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 06/07/2023] [Accepted: 06/08/2023] [Indexed: 06/27/2023]
Abstract
BACKGROUND and rationale: There is increasing evidence that children or young adults having acquired liver disease in childhood display neurocognitive impairment which may become more apparent as they grow older. The molecular, cellular and morphological underpinnings of this clinical problem are incompletely understood. AIM Therefore, we used the advantages of highly-resolved proton magnetic resonance spectroscopy at ultra-high magnetic field to analyze the neurometabolic profile and brain morphometry of children with chronic, compensated liver disease, hypothesizing that with high field spectroscopy we would identify early evidence of rising brain glutamine and decreased myoinositol, such as has been described both in animals and humans with more significant liver disease. METHODS Patients (n = 5) and age-matched controls (n = 19) underwent 7T MR scans and short echo time 1H MR spectra were acquired using the semi-adiabatic SPECIAL sequence in two voxels located in gray and white matter dominated prefrontal cortex, respectively. A 3D MP2RAGE sequence was also acquired for brain volumetry and T1 mapping. Liver disease had to have developed at least 6 months before entering the study. Subjects underwent routine blood analysis and neurocognitive testing using validated methods within 3 months of MRI and MRS. RESULTS Five children currently aged 8-16 years with liver disease acquired in childhood were included. Baseline biological characteristics were similar among patients. There were no statistically significant differences between subjects and controls in brain metabolite levels or brain volumetry. Finally, there were minor neurocognitive fluctuations including attention deficit in one child, but none fell in the statistically significant range. CONCLUSION Children with chronic, compensated liver disease did not display an abnormal neurometabolic profile, neurocognitive abnormalities, or signal intensity changes in the globus pallidus. Despite the absence of neurometabolic changes, it is an opportunity to emphasize that it is only by developing the use of 1H MRS at high field in the clinical arena that we will understand the significance and generalizability of these findings in children with CLD. Attention deficit was observed in one child. Healthy children displayed neurometabolic regional differences as previously reported in adult subjects.
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Affiliation(s)
- Cristina Cudalbu
- CIBM Center for Biomedical Imaging, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Lijing Xin
- CIBM Center for Biomedical Imaging, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Benedicte Marechal
- Advanced Clinical Imaging Technology, Siemens Healthineers International AG, Lausanne, Switzerland; Department of Radiology, Lausanne University Hospital (CHUV) and University of Lausanne, Lausanne, Switzerland; LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Sarah Lachat
- Swiss Pediatric Liver Center, Pediatric Gastroenterology, Hepatology and Nutrition Unit, University Hospitals Geneva, Department of Pediatrics, Gynecology and Obstetrics, University of Geneva Medical School, Geneva, Switzerland
| | - Florence Zangas-Gheri
- Pediatric Neurology Unit, University Hospitals Geneva, Department of Pediatrics, Gynecology and Obstetrics, University of Geneva Medical School, Geneva, Switzerland
| | - Nathalie Valenza
- Pediatric Neurology Unit, University Hospitals Geneva, Department of Pediatrics, Gynecology and Obstetrics, University of Geneva Medical School, Geneva, Switzerland
| | - Sylviane Hanquinet
- Pediatric Radiology Unit, Radiology Division, Diagnostic Department, Children's Hospital, University Hospitals of Geneva, Switzerland
| | - Valérie A McLin
- Swiss Pediatric Liver Center, Pediatric Gastroenterology, Hepatology and Nutrition Unit, University Hospitals Geneva, Department of Pediatrics, Gynecology and Obstetrics, University of Geneva Medical School, Geneva, Switzerland.
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5
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Tiryaki ME, Elmacıoğlu YG, Sitti M. Magnetic guidewire steering at ultrahigh magnetic fields. SCIENCE ADVANCES 2023; 9:eadg6438. [PMID: 37126547 PMCID: PMC10132757 DOI: 10.1126/sciadv.adg6438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
With remote magnetic steering capabilities, magnetically actuated guidewires have proven their potential in minimally invasive medical procedures. Existing magnetic steering strategies, however, have been limited to low magnetic fields, which prevents the integration into medical systems operating at ultrahigh fields (UHF), such as magnetic resonance imaging (MRI) scanners. Here, we present magnetic guidewire design and steering strategies by elucidating the magnetic actuation principles of permanent magnets at UHF. By modeling the uniaxial magnetization behavior of permanent magnets, we outline the magnetic torque and force and demonstrate unique magnetic actuation opportunities at UHF, such as in situ remagnetization. Last, we illustrate the proposed steering principles using a magnetic guidewire composed of neodymium magnets and a fiber optic rod in a 7-Tesla preclinical MRI scanner. The developed UHF magnetic actuation framework would enable next-generation magnetic robots to operate inside MRI scanners.
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Affiliation(s)
- Mehmet Efe Tiryaki
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
- Institute for Biomedical Engineering ETH, Zurich, 8092 Zurich, Switzerland
| | - Yiğit Günsür Elmacıoğlu
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Metin Sitti
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
- Institute for Biomedical Engineering ETH, Zurich, 8092 Zurich, Switzerland
- School of Medicine and College of Engineering, Koç University, 34450 Istanbul, Turkey
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6
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Ladd ME, Quick HH, Speck O, Bock M, Doerfler A, Forsting M, Hennig J, Ittermann B, Möller HE, Nagel AM, Niendorf T, Remy S, Schaeffter T, Scheffler K, Schlemmer HP, Schmitter S, Schreiber L, Shah NJ, Stöcker T, Uder M, Villringer A, Weiskopf N, Zaiss M, Zaitsev M. Germany's journey toward 14 Tesla human magnetic resonance. MAGMA (NEW YORK, N.Y.) 2023; 36:191-210. [PMID: 37029886 PMCID: PMC10140098 DOI: 10.1007/s10334-023-01085-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 04/09/2023]
Abstract
Multiple sites within Germany operate human MRI systems with magnetic fields either at 7 Tesla or 9.4 Tesla. In 2013, these sites formed a network to facilitate and harmonize the research being conducted at the different sites and make this technology available to a larger community of researchers and clinicians not only within Germany, but also worldwide. The German Ultrahigh Field Imaging (GUFI) network has defined a strategic goal to establish a 14 Tesla whole-body human MRI system as a national research resource in Germany as the next progression in magnetic field strength. This paper summarizes the history of this initiative, the current status, the motivation for pursuing MR imaging and spectroscopy at such a high magnetic field strength, and the technical and funding challenges involved. It focuses on the scientific and science policy process from the perspective in Germany, and is not intended to be a comprehensive systematic review of the benefits and technical challenges of higher field strengths.
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Affiliation(s)
- Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.
- Faculty of Medicine, Heidelberg University, Heidelberg, Germany.
- Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany.
- Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Harald H Quick
- Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany
- High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany
| | - Oliver Speck
- Department of Biomedical Magnetic Resonance, Otto von Guericke University Magdeburg, Magdeburg, Germany
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
- Center for Behavioural Brain Sciences, Magdeburg, Germany
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany
| | - Michael Bock
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Arnd Doerfler
- Department of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg (FAU), Erlangen, Germany
| | - Michael Forsting
- Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - Jürgen Hennig
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Bernd Ittermann
- Medical Physics and Metrological Information Technology, Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany
| | - Harald E Möller
- Methods and Development Group Nuclear Magnetic Resonance, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Armin M Nagel
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg (FAU), Erlangen, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Stefan Remy
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany
| | - Tobias Schaeffter
- Medical Physics and Metrological Information Technology, Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany
| | - Klaus Scheffler
- Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Department of Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany
| | | | - Sebastian Schmitter
- Medical Physics and Metrological Information Technology, Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany
| | - Laura Schreiber
- Department of Cardiovascular Imaging, Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
| | - N Jon Shah
- Institute of Neuroscience and Medicine - 4, Forschungszentrum Jülich, Jülich, Germany
| | - Tony Stöcker
- MR Physics, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Michael Uder
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg (FAU), Erlangen, Germany
| | - Arno Villringer
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Nikolaus Weiskopf
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
- Felix Bloch Institute for Solid State Physics, Faculty of Physics and Earth Sciences, Leipzig University, Leipzig, Germany
| | - Moritz Zaiss
- Department of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg (FAU), Erlangen, Germany
| | - Maxim Zaitsev
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
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Zhang Y, Guo Y, Kong X, Zeng P, Yin H, Wu J, He Y, Xu Z. Improving local SNR of a single-channel 54.6 mT MRI system using additional LC-resonator. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 339:107215. [PMID: 35421711 DOI: 10.1016/j.jmr.2022.107215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 03/15/2022] [Accepted: 04/02/2022] [Indexed: 06/14/2023]
Abstract
Very-low field magnetic resonance imaging (VLF-MRI, B0 < 0.1T) has an essential application in medical imaging diagnosis because of its light weight and low cost. For single-channel RF coil VLF-MRI system, a planar spiral LC-resonator placed on the surface of samples was designed to improve the local SNR. First, an equivalent circuit model was established to evaluate the boosting effects on radiofrequency (RF) magnetic field and SNR. Second, the relationship between the resonant capacitance and the transmission coefficient was deduced according to the circuit model, and the appropriate resonant capacitance was obtained. Then, the influence of the diameter and the number of turns of the LC-resonator on the SNR is considered, and the structure of the LC-resonator was optimized to maximize the SNR. Finally, a phantom MRI experiment was carried out with our home-built 54.6 mT MRI system to compare the SNR of the experiment with the calculation, the SNR enhancement trend of the two was consistent. Additional experiments were conducted using orange and chicken leg to demonstrate the SNR enhancement abilities of the LC-resonator. The enhancement of SNR reached up to 1.8-fold and 2.2-fold depending on the distance between the sample and LC-resonator. For comparison, we conducted imaging experiments on surface receiving coil with the same parameters, and the results show that the SNR of the LC resonator is comparable to that of the surface coil. The reported LC-resonator provide a low-cost local enhancement method for VLF-MRI.
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Affiliation(s)
- Yana Zhang
- State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, 174 Shazheng St., Shapingba Dist., Chongqing 400044, China
| | - Yi Guo
- State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, 174 Shazheng St., Shapingba Dist., Chongqing 400044, China
| | - Xiaohan Kong
- State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, 174 Shazheng St., Shapingba Dist., Chongqing 400044, China
| | - Ping Zeng
- State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, 174 Shazheng St., Shapingba Dist., Chongqing 400044, China
| | - Hang Yin
- State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, 174 Shazheng St., Shapingba Dist., Chongqing 400044, China
| | - Jiamin Wu
- State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, 174 Shazheng St., Shapingba Dist., Chongqing 400044, China
| | - Yucheng He
- State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, 174 Shazheng St., Shapingba Dist., Chongqing 400044, China
| | - Zheng Xu
- State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, 174 Shazheng St., Shapingba Dist., Chongqing 400044, China.
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Patient Comfort in Modern Computed Tomography: What Really Counts. Tomography 2022; 8:1401-1412. [PMID: 35645399 PMCID: PMC9149918 DOI: 10.3390/tomography8030113] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/19/2022] [Accepted: 05/19/2022] [Indexed: 11/17/2022] Open
Abstract
Background: The purpose of the present study is to evaluate the patient comfort during CT examinations with a modern CT scanner (Photon-Counting CT (PCCT)) and to compare the perceived patient comfort with a standard CT scanner. Methods: A total of 157 patients participated in this study and completed a questionnaire on their subjective perceptions after their CT examination. The following aspects of comfort were rated on a 5-point Likert scale: (1) claustrophobia in general and during the examination, (2) the effort to lie down and to get up from the CT table, (3) the speed and comfort of the CT table, (4) the difficulty of holding the breath during the CT scan, and (5) the communication during the examination. Results: Patients rated the modern CT scanner significantly better in terms of speed and comfort of the CT table and in terms of difficulty of holding their breath during the CT scan. The answers regarding the other aspects of comfort did not reveal significant differences. When asked for a comparison, patients who did perceive a difference between both scanners rated the modern CT scanner as more comfortable in all aspects of comfort. Conclusions: The survey did not reveal any major deficits in terms of comfort on the standard CT scanner. However, patients perceived the structural changes positively and appreciated the comfort of a modern CT scanner.
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Hansson B, Simic M, Olsrud J, Markenroth Bloch K, Owman T, Sundgren PC, Björkman-Burtscher IM. MR- safety: Evaluation of compliance with screening routines using a structured screening interview. JOURNAL OF PATIENT SAFETY AND RISK MANAGEMENT 2022. [DOI: 10.1177/25160435221077493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Magnetic resonance (MR) safety procedures are designed to allow patients, research subjects and personnel to enter the MR-scanner room under controlled conditions and without the risk to be harmed during the examination. Ferromagnetic objects in the MR-environment or inside the human body represent the main safety risks potentially leading to human injuries. Screening for MR-safety risks with dedicated procedures is therefore mandatory. As human errors during the screening procedure might align and lead to an incident compliance is essential. Purpose To evaluate compliance with a documented structured MR-safety screening process. Method Written and signed MR-safety screening documentation collected at a national 7T MR facility during a four-year period was evaluated for compliance of trained personnel with multi-step MR-safety routines. We analysed whether examinations were performed or why they were not performed. Data analysis further included descriptive statistics of the study population (age, gender and patient or healthy volunteer status), identification of missing documents and omitted or incorrect answers, and whether these compliance shortcomings concerned predominantly administrative or MR-safety related issues. Results Documentation of the screening process in 1819 subjects was incomplete in 19% of subjects. The most common documentation shortcoming was omitted fields. Out of 478 omitted answer-fields in 307 subjects, 36% were of administrative nature and 64% related directly to MR-safety issues. Conclusion Compliance with MR-safety screening procedures cannot be taken for granted and deficiencies to comply with screening routines were revealed. Documentation shortcomings concerned both administrative and MR-safety related issues.
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Affiliation(s)
- Boel Hansson
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
- Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Matea Simic
- Karolinska University Hospital, Solna Stockholm, Sweden
| | - Johan Olsrud
- Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | | | - Titti Owman
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
- Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Pia C Sundgren
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
- Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
- Karolinska University Hospital, Solna Stockholm, Sweden
| | - Isabella M Björkman-Burtscher
- Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden
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10
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Ineichen BV, Beck ES, Piccirelli M, Reich DS. New Prospects for Ultra-High-Field Magnetic Resonance Imaging in Multiple Sclerosis. Invest Radiol 2021; 56:773-784. [PMID: 34120128 PMCID: PMC8505164 DOI: 10.1097/rli.0000000000000804] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/09/2021] [Accepted: 05/09/2021] [Indexed: 11/26/2022]
Abstract
ABSTRACT There is growing interest in imaging multiple sclerosis (MS) through the ultra-high-field (UHF) lens, which currently means a static magnetic field strength of 7 T or higher. Because of higher signal-to-noise ratio and enhanced susceptibility effects, UHF magnetic resonance imaging improves conspicuity of MS pathological hallmarks, among them cortical demyelination and the central vein sign. This could, in turn, improve confidence in MS diagnosis and might also facilitate therapeutic monitoring of MS patients. Furthermore, UHF imaging offers unique insight into iron-related pathology, leptomeningeal inflammation, and spinal cord pathologies in neuroinflammation. Yet, limitations such as the longer scanning times to achieve improved resolution and incipient safety data on implanted medical devices need to be considered. In this review, we discuss applications of UHF imaging in MS, its advantages and limitations, and practical aspects of UHF in the clinical setting.
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Affiliation(s)
- Benjamin V. Ineichen
- From the Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
- Department of Neuroradiology, Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Erin S. Beck
- From the Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Marco Piccirelli
- Department of Neuroradiology, Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Daniel S. Reich
- From the Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
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11
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Ljungberg E, Damestani NL, Wood TC, Lythgoe DJ, Zelaya F, Williams SCR, Solana AB, Barker GJ, Wiesinger F. Silent zero TE MR neuroimaging: Current state-of-the-art and future directions. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2021; 123:73-93. [PMID: 34078538 PMCID: PMC7616227 DOI: 10.1016/j.pnmrs.2021.03.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 06/12/2023]
Abstract
Magnetic Resonance Imaging (MRI) scanners produce loud acoustic noise originating from vibrational Lorentz forces induced by rapidly changing currents in the magnetic field gradient coils. Using zero echo time (ZTE) MRI pulse sequences, gradient switching can be reduced to a minimum, which enables near silent operation.Besides silent MRI, ZTE offers further interesting characteristics, including a nominal echo time of TE = 0 (thus capturing short-lived signals from MR tissues which are otherwise MR-invisible), 3D radial sampling (providing motion robustness), and ultra-short repetition times (providing fast and efficient scanning).In this work we describe the main concepts behind ZTE imaging with a focus on conceptual understanding of the imaging sequences, relevant acquisition parameters, commonly observed image artefacts, and image contrasts. We will further describe a range of methods for anatomical and functional neuroimaging, together with recommendations for successful implementation.
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Affiliation(s)
- Emil Ljungberg
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom.
| | - Nikou L Damestani
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Tobias C Wood
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - David J Lythgoe
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Fernando Zelaya
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Steven C R Williams
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | | | - Gareth J Barker
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Florian Wiesinger
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom; ASL Europe, GE Healthcare, Munich, Germany
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12
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Happo S, Keränen T, Halkoaho A, Lehto SM. Risk Assessment of Medical Study Procedures in the Documents Submitted to a Research Ethics Committee. J Empir Res Hum Res Ethics 2020; 15:396-406. [PMID: 32036724 PMCID: PMC7604935 DOI: 10.1177/1556264620903563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Several frameworks assist research ethics committees (RECs) in risk assessment of medical studies. However, little is known about how researchers describe risks of the procedures in study protocols and participant information sheets. We examined 349 study protocols and participant information sheets submitted to an REC and evaluated the risk assessments performed for 1,510 study procedures. Risks had been assessed for 399 (26%) procedures in study protocols and for 425 (28%) procedures in participant information sheets. Physical risks were assessed six times more frequently than psychological risks. Risks of medical procedures are not always detailed in study protocols or participant information sheets. Risk descriptions of procedures believed to be familiar to potential participants may be omitted.
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Affiliation(s)
- Saara Happo
- University of Eastern Finland, Kuopio, Finland
| | | | | | - Soili M. Lehto
- University of Eastern Finland, Kuopio, Finland
- University of Helsinki, Finland
- Helsinki University Hospital, Finland
- Kuopio University Hospital, Finland
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13
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Ji Y, Winter L, Navarro L, Ku MC, Periquito JS, Pham M, Hoffmann W, Theune LE, Calderón M, Niendorf T. Controlled Release of Therapeutics from Thermoresponsive Nanogels: A Thermal Magnetic Resonance Feasibility Study. Cancers (Basel) 2020; 12:cancers12061380. [PMID: 32471299 PMCID: PMC7352924 DOI: 10.3390/cancers12061380] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/23/2020] [Accepted: 05/25/2020] [Indexed: 12/16/2022] Open
Abstract
Thermal magnetic resonance (ThermalMR) accommodates radio frequency (RF)-induced temperature modulation, thermometry, anatomic and functional imaging, and (nano)molecular probing in an integrated RF applicator. This study examines the feasibility of ThermalMR for the controlled release of a model therapeutics from thermoresponsive nanogels using a 7.0-tesla whole-body MR scanner en route to local drug-delivery-based anticancer treatments. The capacity of ThermalMR is demonstrated in a model system involving the release of fluorescein-labeled bovine serum albumin (BSA-FITC, a model therapeutic) from nanometer-scale polymeric networks. These networks contain thermoresponsive polymers that bestow environmental responsiveness to physiologically relevant changes in temperature. The release profile obtained for the reference data derived from a water bath setup used for temperature stimulation is in accordance with the release kinetics deduced from the ThermalMR setup. In conclusion, ThermalMR adds a thermal intervention dimension to an MRI device and provides an ideal testbed for the study of the temperature-induced release of drugs, magnetic resonance (MR) probes, and other agents from thermoresponsive carriers. Integrating diagnostic imaging, temperature intervention, and temperature response control, ThermalMR is conceptually appealing for the study of the role of temperature in biology and disease and for the pursuit of personalized therapeutic drug delivery approaches for better patient care.
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Affiliation(s)
- Yiyi Ji
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbruck Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany; (Y.J.); (M.-C.K.); (J.S.P.); (M.P.)
| | - Lukas Winter
- Physikalisch-Technische Bundesanstalt (PTB), 10587 Berlin, Germany; (L.W.); (W.H.)
| | - Lucila Navarro
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, 14195 Berlin, Germany; (L.N.); (L.E.T.); (M.C.)
- Instituto de Desarrollo Tecnológico para la Industria Química (INTEC), Universidad Nacional del Litoral (UNL)—Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Santa Fe 3000, Argentina
| | - Min-Chi Ku
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbruck Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany; (Y.J.); (M.-C.K.); (J.S.P.); (M.P.)
| | - João S. Periquito
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbruck Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany; (Y.J.); (M.-C.K.); (J.S.P.); (M.P.)
| | - Michal Pham
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbruck Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany; (Y.J.); (M.-C.K.); (J.S.P.); (M.P.)
| | - Werner Hoffmann
- Physikalisch-Technische Bundesanstalt (PTB), 10587 Berlin, Germany; (L.W.); (W.H.)
| | - Loryn E. Theune
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, 14195 Berlin, Germany; (L.N.); (L.E.T.); (M.C.)
| | - Marcelo Calderón
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, 14195 Berlin, Germany; (L.N.); (L.E.T.); (M.C.)
- POLYMAT and Applied Chemistry Department, Faculty of Chemistry, University of the Basque Country UPV/EHU, 20018 Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbruck Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany; (Y.J.); (M.-C.K.); (J.S.P.); (M.P.)
- Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany
- Correspondence: ; Tel.: +49-30-9406-4505
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14
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Friebe B. Editorial for "Subjectively reported Effects Experienced in an Actively Shielded 7T MR: A Large-Scale Study". J Magn Reson Imaging 2020; 52:1277-1278. [PMID: 32255525 DOI: 10.1002/jmri.27157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 11/10/2022] Open
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15
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Abbas H, Broche LM, Ezdoglian A, Li D, Yuecel R, James Ross P, Cheyne L, Wilson HM, Lurie DJ, Dawson DK. Fast field-cycling magnetic resonance detection of intracellular ultra-small iron oxide particles in vitro: Proof-of-concept. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 313:106722. [PMID: 32248086 PMCID: PMC7167511 DOI: 10.1016/j.jmr.2020.106722] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 06/11/2023]
Abstract
PURPOSE Inflammation is central in disease pathophysiology and accurate methods for its detection and quantification are increasingly required to guide diagnosis and therapy. Here we explored the ability of Fast Field-Cycling Magnetic Resonance (FFC-MR) in quantifying the signal of ultra-small superparamagnetic iron oxide particles (USPIO) phagocytosed by J774 macrophage-like cells as a proof-of-principle. METHODS Relaxation rates were measured in suspensions of J774 macrophage-like cells loaded with USPIO (0-200 μg/ml Fe as ferumoxytol), using a 0.25 T FFC benchtop relaxometer and a human whole-body, in-house built 0.2 T FFC-MR prototype system with a custom test tube coil. Identical non-imaging, saturation recovery pulse sequence with 90° flip angle and 20 different evolution fields selected logarithmically between 80 μT and 0.2 T (3.4 kHz and 8.51 MHz proton Larmor frequency [PLF] respectively). Results were compared with imaging flow cytometry quantification of side scatter intensity and USPIO-occupied cell area. A reference colorimetric iron assay was used. RESULTS The T1 dispersion curves derived from FFC-MR were excellent in detecting USPIO at all concentrations examined (0-200 μg/ml Fe as ferumoxytol) vs. control cells, p ≤ 0.001. FFC-NMR was capable of reliably detecting cellular iron content as low as 1.12 ng/µg cell protein, validated using a colorimetric assay. FFC-MR was comparable to imaging flow cytometry quantification of side scatter intensity but superior to USPIO-occupied cell area, the latter being only sensitive at exposures ≥ 10 µg/ml USPIO. CONCLUSIONS We demonstrated for the first time that FFC-MR is capable of quantitative assessment of intra-cellular iron which will have important implications for the use of USPIO in a variety of biological applications, including the study of inflammation.
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Affiliation(s)
- Hassan Abbas
- Aberdeen Cardiovascular and Diabetes Centre, University of Aberdeen, Aberdeen, United Kingdom.
| | - Lionel M Broche
- Bio-Medical Physics, School of Medicine, University of Aberdeen, Aberdeen, United Kingdom
| | - Aiarpi Ezdoglian
- Iain Fraser Cytometry Centre, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom; Department of Medical Chemistry and Toxicology, NI Pirogov Russian National Research Medical University, Moscow 117997, Russian Federation(1)
| | - Dmitriy Li
- Iain Fraser Cytometry Centre, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Raif Yuecel
- Iain Fraser Cytometry Centre, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom; Cytomics Centre, College of Life and Environmental Sciences, University of Exeter, EX4 4QD, United Kingdom(1)
| | - P James Ross
- Bio-Medical Physics, School of Medicine, University of Aberdeen, Aberdeen, United Kingdom
| | - Lesley Cheyne
- Aberdeen Cardiovascular and Diabetes Centre, University of Aberdeen, Aberdeen, United Kingdom
| | - Heather M Wilson
- Aberdeen Cardiovascular and Diabetes Centre, University of Aberdeen, Aberdeen, United Kingdom
| | - David J Lurie
- Bio-Medical Physics, School of Medicine, University of Aberdeen, Aberdeen, United Kingdom
| | - Dana K Dawson
- Aberdeen Cardiovascular and Diabetes Centre, University of Aberdeen, Aberdeen, United Kingdom.
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16
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Hansson B, Markenroth Bloch K, Owman T, Nilsson M, Lätt J, Olsrud J, Björkman-Burtscher IM. Subjectively Reported Effects Experienced in an Actively Shielded 7T MRI: A Large-Scale Study. J Magn Reson Imaging 2020; 52:1265-1276. [PMID: 32196818 DOI: 10.1002/jmri.27139] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 03/03/2020] [Accepted: 03/03/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Ultrahigh-field (UHF) MRI advances towards clinical use. Patient compliance is generally high, but few large-scale studies have investigated the effects experienced in 7T MRI systems, especially considering peripheral nerve stimulation (PNS) and caregiving. PURPOSE To evaluate the quantity, the intensity, and subjective experiences from short-term effects, focusing on the levels of comfort and compliance of subjects. STUDY TYPE Prospective. POPULATION In all, 954 consecutive MRIs in 801 subjects for 3 years. FIELD STRENGTH 7T. ASSESSMENT After the 7T examination, a questionnaire was used to collect data. STATISTICAL TESTS Descriptive statistics, Spearman's rank correlation, Mann-Whitney U-test, and t-test. RESULTS The majority (63%) of subjects agreed that the MRI experience was comfortable and 93% would be willing to undergo future 7T MRI as a patient (5% undecided) and 82% for research purposes (12% undecided). The most common short-term effects experienced were dizziness (81%), inconsistent movement (68%), PNS (63%), headache (40%), nausea (32%), metallic taste (12%), and light flashes (8%). Of the subjects who reported having PNS (n = 603), 44% experienced PNS as "not uncomfortable at all," 45% as "little or very little uncomfortable," and 11% as "moderate to very much uncomfortable." Scanner room temperature was experienced more comfortable before (78%) than during (58%) examinations, and the noise level was acceptable by 90% of subjects. Anxiety before the examination was reported by 43%. Patients differed from healthy volunteers regarding an experience of headache, metallic taste, dizziness, or anxiety. Room for improvement was pointed out after 117 examinations concerning given information (n = 73), communication and sound system (n = 35), or nursing care (n = 15). DATA CONCLUSION Subjectively reported effects occur in actively shielded 7T MRI and include physiological responses and individual psychological issues. Although leaving room for improvement, few subjects experienced these effects being so uncomfortable that they would lead to aversion to future UHF examinations. LEVEL OF EVIDENCE 1 TECHNICAL EFFICACY: Stage 5 J. Magn. Reson. Imaging 2020;52:1265-1276.
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Affiliation(s)
- Boel Hansson
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden.,Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | | | - Titti Owman
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden.,Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Markus Nilsson
- Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Jimmy Lätt
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
| | - Johan Olsrud
- Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Isabella M Björkman-Burtscher
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden.,Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden.,Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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17
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Duan G, Zhao X, Anderson SW, Zhang X. Boosting magnetic resonance imaging signal-to-noise ratio using magnetic metamaterials. COMMUNICATIONS PHYSICS 2019; 2:35. [PMID: 31673637 PMCID: PMC6822984 DOI: 10.1038/s42005-019-0135-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 02/21/2019] [Indexed: 06/01/2023]
Abstract
Magnetic resonance imaging (MRI) represents a mainstay among the diagnostic imaging tools in modern healthcare. Signal-to-noise ratio (SNR) represents a fundamental performance metric of MRI, the improvement of which may be translated into increased image resolution or decreased scan time. Recently, efforts towards the application of metamaterials in MRI have reported improvements in SNR through their capacity to interact with electromagnetic radiation. While promising, the reported applications of metamaterials to MRI remain impractical and fail to realize the full potential of these unique materials. Here, we report the development of a magnetic metamaterial enabling a marked boost in radio frequency field strength, ultimately yielding a dramatic increase in the SNR (~ 4.2X) of MRI. The application of the reported magnetic metamaterials in MRI has the potential for rapid clinical translation, offering marked enhancements in SNR, image resolution, and scan efficiency, thereby leading to an evolution of this diagnostic tool.
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Affiliation(s)
- Guangwu Duan
- Department of Mechanical Engineering and Photonics Center, Boston University, Boston, MA 02215, USA
| | - Xiaoguang Zhao
- Department of Mechanical Engineering and Photonics Center, Boston University, Boston, MA 02215, USA
| | | | - Xin Zhang
- Department of Mechanical Engineering and Photonics Center, Boston University, Boston, MA 02215, USA
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18
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Hoff MN, McKinney A, Shellock FG, Rassner U, Gilk T, Watson RE, Greenberg TD, Froelich J, Kanal E. Safety Considerations of 7-T MRI in Clinical Practice. Radiology 2019; 292:509-518. [PMID: 31310177 DOI: 10.1148/radiol.2019182742] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Although 7-T MRI has recently received approval for use in clinical patient care, there are distinct safety issues associated with this relatively high magnetic field. Forces on metallic implants and radiofrequency power deposition and heating are safety considerations at 7 T. Patient bioeffects such as vertigo, dizziness, false feelings of motion, nausea, nystagmus, magnetophosphenes, and electrogustatory effects are more common and potentially more pronounced at 7 T than at lower field strengths. Herein the authors review safety issues associated with 7-T MRI. The rationale for safety concerns at this field strength are discussed as well as potential approaches to mitigate risk to patients and health care professionals.
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Affiliation(s)
- Michael N Hoff
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Alexander McKinney
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Frank G Shellock
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Ulrich Rassner
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Tobias Gilk
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Robert E Watson
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Todd D Greenberg
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Jerry Froelich
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Emanuel Kanal
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
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19
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Hansson B, Höglund P, Markenroth Bloch K, Nilsson M, Olsrud J, Wilén J, Björkman-Burtscher IM. Short-term effects experienced during examinations in an actively shielded 7 T MR. Bioelectromagnetics 2019; 40:234-249. [PMID: 30920671 PMCID: PMC6593459 DOI: 10.1002/bem.22189] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 03/12/2019] [Indexed: 01/18/2023]
Abstract
The objective of this study was to evaluate occurrence and strength of short-term effects experienced by study participants in an actively shielded (AS) 7 tesla (7 T) magnetic resonance (MR) scanner, to compare results with earlier reports on passively shielded (PS) 7 T MR scanners, and to outline possible healthcare strategies to improve patient compliance. Study participants (n = 124) completed a web-based questionnaire directly after being examined in an AS 7 T MR (n = 154 examinations). Most frequently experienced short-term effects were dizziness (84%) and inconsistent movement (70%), especially while moving into or out of the magnet. Peripheral nerve stimulation (PNS)-twitching-was experienced in 67% of research examinations and showed a dependence between strength of twitches and recorded predicted PNS values. Of the participants, 74% experienced noise levels as acceptable and the majority experienced body and room temperature as comfortable. Of the study participants, 95% felt well-informed and felt they had had good contact with the staff before the examination. Willingness to undergo a future 7 T examination was high (>90%). Our study concludes short-term effects are often experienced during examinations in an AS 7 T MR, leaving room for improvement in nursing care strategies to increase patient compliance. Bioelectromagnetics. 2019;9999:XX-XX. © 2019 The Authors. Bioelectromagnetics Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Boel Hansson
- Department of Diagnostic Radiology, Skåne University Hospital, Lund, Sweden.,Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Peter Höglund
- Department of Clinical Pharmacology, Lund University, Lund, Sweden
| | | | - Markus Nilsson
- Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Johan Olsrud
- Department of Diagnostic Radiology, Skåne University Hospital, Lund, Sweden.,Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Jonna Wilén
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Isabella M Björkman-Burtscher
- Department of Diagnostic Radiology, Skåne University Hospital, Lund, Sweden.,Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden.,Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Budinger TF, Bird MD. MRI and MRS of the human brain at magnetic fields of 14 T to 20 T: Technical feasibility, safety, and neuroscience horizons. Neuroimage 2018; 168:509-531. [DOI: 10.1016/j.neuroimage.2017.01.067] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 01/23/2017] [Accepted: 01/27/2017] [Indexed: 11/16/2022] Open
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Patient comfort during positron emission tomography/magnetic resonance and positron emission tomography/computed tomography examinations: subjective assessments with visual analog scales. Invest Radiol 2016; 50:726-32. [PMID: 26039772 DOI: 10.1097/rli.0000000000000177] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVES The aims of this study were to investigate subjective perceptions and sensory side effects during whole-body positron emission tomography (PET)/magnetic resonance (MR) examinations and to evaluate differences between PET/MR and standard PET/computed tomography (CT) examinations. MATERIAL AND METHODS During prospective clinical trials using a PET/MR hybrid system after a standard PET/CT examination, 266 patients (including 19 juveniles) were asked to complete questionnaires on causes of discomfort and side effects after both examinations (self-assessment). In case of complaints regarding causes of discomfort, physicians were also asked to complete the questionnaires to provide an external assessment. Visual analog scales were used for the ratings. RESULTS Seventy-four percent (183/247) of all adult patients and 68% (13/19) of all teenage patients completed the questionnaires. In most of the cases, patient compliance was good and allowed for the acquisition of diagnostic images. Most patients did not report side effects or discomfort at all. Only 11 of 247 PET/MR scans of adult patients (4.4%) and 4 of 19 scans of juvenile patients (21%) were aborted prematurely by the patients' requests; however, this did not influence the final PET/MR diagnoses in most cases (12/15). In terms of noise levels and examination times, patients rated the PET/MR significantly lower than the PET/CT. With the exception of male patients not tolerating the examination time as well as female patients, no significant influences of sex, age, body mass index, and real scan times were observed. The attending physicians tended to underestimate their patient's discomfort, particularly when the discomfort was because of time (in the case of children) or noise exposure (all patients). CONCLUSIONS Patient comfort should drive the design and development of optimized scanner types, workflow processes, and scan protocols. For PET/MR, the most important aim should be to shorten the scan time. However, patient-centered management may be the best instrument to improve patient compliance.
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Mian OS, Li Y, Antunes A, Glover PM, Day BL. Effect of head pitch and roll orientations on magnetically induced vertigo. J Physiol 2016; 594:1051-67. [PMID: 26614577 PMCID: PMC4753258 DOI: 10.1113/jp271513] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/19/2015] [Indexed: 11/10/2022] Open
Abstract
KEY POINTS Lying supine in a strong magnetic field, such as in magnetic resonance imaging scanners, can induce a perception of whole-body rotation. The leading hypothesis to explain this invokes a Lorentz force mechanism acting on vestibular endolymph that acts to stimulate semicircular canals. The hypothesis predicts that the perception of whole-body rotation will depend on head orientation in the field. Results showed that the direction and magnitude of apparent whole-body rotation while stationary in a 7 T magnetic field is influenced by head orientation. The data are compatible with the Lorentz force hypothesis of magnetic vestibular stimulation and furthermore demonstrate the operation of a spatial transformation process from head-referenced vestibular signals to Earth-referenced body motion. ABSTRACT High strength static magnetic fields are known to induce vertigo, believed to be via stimulation of the vestibular system. The leading hypothesis (Lorentz forces) predicts that the induced vertigo should depend on the orientation of the magnetic field relative to the head. In this study we examined the effect of static head pitch (-80 to +40 deg; 12 participants) and roll (-40 to +40 deg; 11 participants) on qualitative and quantitative aspects of vertigo experienced in the dark by healthy humans when exposed to the static uniform magnetic field inside a 7 T MRI scanner. Three participants were additionally examined at 180 deg pitch and roll orientations. The effect of roll orientation on horizontal and vertical nystagmus was also measured and was found to affect only the vertical component. Vertigo was most discomforting when head pitch was around 60 deg extension and was mildest when it was around 20 deg flexion. Quantitative analysis of vertigo focused on the induced perception of horizontal-plane rotation reported online with the aid of hand-held switches. Head orientation had effects on both the magnitude and the direction of this perceived rotation. The data suggest sinusoidal relationships between head orientation and perception with spatial periods of 180 deg for pitch and 360 deg for roll, which we explain is consistent with the Lorentz force hypothesis. The effects of head pitch on vertigo and previously reported nystagmus are consistent with both effects being driven by a common vestibular signal. To explain all the observed effects, this common signal requires contributions from multiple semicircular canals.
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Affiliation(s)
- Omar S Mian
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, UK
| | - Yan Li
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK
| | - Andre Antunes
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK
| | - Paul M Glover
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK
| | - Brian L Day
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, UK
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Subjective perception of safety in healthy individuals working with 7 T MRI scanners: a retrospective multicenter survey. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2016; 29:379-87. [DOI: 10.1007/s10334-016-0527-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 01/14/2016] [Accepted: 01/15/2016] [Indexed: 10/22/2022]
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Schaap K, Portengen L, Kromhout H. Exposure to MRI-related magnetic fields and vertigo in MRI workers. Occup Environ Med 2015; 73:161-6. [PMID: 26561507 DOI: 10.1136/oemed-2015-103019] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 10/21/2015] [Indexed: 11/04/2022]
Abstract
OBJECTIVES Vertigo has been reported by people working around magnetic resonance imaging (MRI) scanners and was found to increase with increasing strength of scanner magnets. This suggests an association with exposure to static magnetic fields (SMF) and/or motion-induced time-varying magnetic fields (TVMF). This study assessed the association between various metrics of shift-long exposure to SMF and TVMF and self-reported vertigo among MRI workers. METHODS We analysed 358 shifts from 234 employees at 14 MRI facilities in the Netherlands. Participants used logbooks to report vertigo experienced during the work day at the MRI facility. In addition, personal exposure to SMF and TVMF was measured during the same shifts, using portable magnetic field dosimeters. RESULTS Vertigo was reported during 22 shifts by 20 participants and was significantly associated with peak and time-weighted average (TWA) metrics of SMF as well as TVMF exposure. Associations were most evident with full-shift TWA TVMF exposure. The probability of vertigo occurrence during a work shift exceeded 5% at peak exposure levels of 409 mT and 477 mT/s and at full-shift TWA levels of 3 mT and 0.6 mT/s. CONCLUSIONS These results confirm the hypothesis that vertigo is associated with exposure to MRI-related SMF and TVMF. Strong correlations between various metrics of shift-long exposure make it difficult to disentangle the effects of SMF and TVMF exposure, or identify the most relevant exposure metric. On the other hand, this also implies that several metrics of shift-long exposure to SMF and TVMF should perform similarly in epidemiological studies on MRI-related vertigo.
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Affiliation(s)
- Kristel Schaap
- Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Lützen Portengen
- Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Hans Kromhout
- Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
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Klix S, Els A, Paul K, Graessl A, Oezerdem C, Weinberger O, Winter L, Thalhammer C, Huelnhagen T, Rieger J, Mehling H, Schulz-Menger J, Niendorf T. On the subjective acceptance during cardiovascular magnetic resonance imaging at 7.0 Tesla. PLoS One 2015; 10:e0117095. [PMID: 25621491 PMCID: PMC4306482 DOI: 10.1371/journal.pone.0117095] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 12/18/2014] [Indexed: 12/25/2022] Open
Abstract
PURPOSE This study examines the subjective acceptance during UHF-CMR in a cohort of healthy volunteers who underwent a cardiac MR examination at 7.0T. METHODS Within a period of two-and-a-half years (January 2012 to June 2014) a total of 165 healthy volunteers (41 female, 124 male) without any known history of cardiac disease underwent UHF-CMR. For the assessment of the subjective acceptance a questionnaire was used to examine the participants experience prior, during and after the UHF-CMR examination. For this purpose, subjects were asked to respond to the questionnaire in an exit interview held immediately after the completion of the UHF-CMR examination under supervision of a study nurse to ensure accurate understanding of the questions. All questions were answered with "yes" or "no" including space for additional comments. RESULTS Transient muscular contraction was documented in 12.7% of the questionnaires. Muscular contraction was reported to occur only during periods of scanning with the magnetic field gradients being rapidly switched. Dizziness during the study was reported by 12.7% of the subjects. Taste of metal was reported by 10.1% of the study population. Light flashes were reported by 3.6% of the entire cohort. 13% of the subjects reported side effects/observations which were not explicitly listed in the questionnaire but covered by the question about other side effects. No severe side effects as vomiting or syncope after scanning occurred. No increase in heart rate was observed during the UHF-CMR exam versus the baseline clinical examination. CONCLUSIONS This study adds to the literature by detailing the subjective acceptance of cardiovascular magnetic resonance imaging examinations at a magnetic field strength of 7.0T. Cardiac MR examinations at 7.0T are well tolerated by healthy subjects. Broader observational and multi-center studies including patient cohorts with cardiac diseases are required to gain further insights into the subjective acceptance of UHF-CMR examinations.
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Affiliation(s)
- Sabrina Klix
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Antje Els
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Katharina Paul
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Andreas Graessl
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Celal Oezerdem
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Oliver Weinberger
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Lukas Winter
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Christof 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
| | - Jan Rieger
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Heidrun Mehling
- Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Jeanette Schulz-Menger
- Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
- HELIOS Klinikum Berlin-Buch, Dept. of Cardiology and Nephrology, 13125 Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, 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
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The role of latency period in quality management for free-breathing coronary wall MRI. Int J Cardiovasc Imaging 2015; 31:621-7. [PMID: 25573687 DOI: 10.1007/s10554-014-0586-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 12/31/2014] [Indexed: 10/24/2022]
Abstract
The aim of the present study was to determine the effects of the latency period on the performance of free-breathing coronary wall MRI. With the approval of IRB, 70 participants were recruited for coronary wall magnetic resonance imaging (MRI) and provided written informed consent. In 35 subjects, right coronary segments (RCA1-3) were imaged first; in the remaining subjects, the left coronary segments (LM and LAD1-3) were imaged first. The images were classified into groups; group 1 contained right coronary images from the subjects whose right coronary segments were imaged first and left coronary images from the subjects whose left coronary segments were imaged first. Group 2 contained the other coronary segments. The image scores (ranked1-3), latency periods, drift of the position of the navigator (NAV), scan efficiency were compared between image groups. Image group 1 has higher scores (1.66 ± 0.55 vs. 1.46 ± 0.51), shorter latency periods (32.04 ± 4.24 vs. 44.22 ± 5.57 min), lower drift in the location of the NAV (1.90 ± 1.27 mm vs. 2.61 ± 1.71 mm) and higher scan efficiency (32.7 ± 7.6 vs. 29.9 ± 7.9%) than group 2. Long latency periods have a significantly negative impact on the image quality of coronary wall MRI.
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Uwano I, Metoki T, Sendai F, Yoshida R, Kudo K, Yamashita F, Higuchi S, Ito K, Harada T, Goodwin J, Ogawa A, Sasaki M. Assessment of sensations experienced by subjects during MR imaging examination at 7T. Magn Reson Med Sci 2014; 14:35-41. [PMID: 25345414 DOI: 10.2463/mrms.2014-0004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE We investigated sensations experienced by a large number of subjects during magnetic resonance (MR) imaging examinations using a 7-tesla scanner and slow table-feed speed. METHODS After examinations at 7T, 504 of 508 consecutive subjects completed questionnaires using an 11-point scale to rate 14 potential sensations and symptoms during table movement and stationary positioning of the table. We compared scores among the sensations and between table conditions and the mean values of the scores with those reported in previous studies and examined correlations between the scores and subject characteristics. RESULTS Vertigo and feelings of curving or leaning in the right or left direction during table movement were experienced frequently and markedly compared to other sensations and sensations experienced when the table was stationary (P < 0.01) and were correlated with subject age and examination time (P < 0.05). However, moderate to severe (scores of 5 to 10) vertigo and a curving/leaning feeling during table movement were noted in only 10.5% (vertigo) and 10.9% (curving/leaning) of subjects, and the mean vertigo score, 1.26, appeared to be substantially lower than that reported in a previous study. Reports of a metallic taste, nausea, and light flashes were significantly rarer and weaker than other sensations (P < 0.05). CONCLUSION Vertigo and feelings of curving during table movement were the most frequent sensations reported during MR imaging examination at 7T. However, the occurrence and severity were low and mild, presumably because of the slow table-feed speed, which suggests that most patients and volunteers found discomfort at 7T acceptable.
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Affiliation(s)
- Ikuko Uwano
- Division of Ultrahigh Field MRI, Institute for Biomedical Sciences, Iwate Medical University
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Chou IJ, Tench CR, Gowland P, Jaspan T, Dineen RA, Evangelou N, Abdel-Fahim R, Whitehouse WP, Constantinescu CS. Subjective discomfort in children receiving 3 T MRI and experienced adults' perspective on children's tolerability of 7 T: a cross-sectional questionnaire survey. BMJ Open 2014; 4:e006094. [PMID: 25320001 PMCID: PMC4201995 DOI: 10.1136/bmjopen-2014-006094] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVES To explore the possible discomfort perceived by children participating in 7 T MRI research, and the age range in which children are most likely to tolerate it well. DESIGN A cross-sectional survey using age-appropriate questionnaires containing six measures of subjective discomfort (general discomfort, dizziness, noisiness, claustrophobia and feeling of cold or warm). SETTING For children, 3 T clinical scanner in a tertiary referral teaching hospital; for adults, 3 and 7 T scanner in a university research building. PARTICIPANTS Non-sedated children and young people under 18 years of age who underwent 3 T clinical MRI for brain or musculoskeletal scans and adult volunteers attending 7 T with or without 3 T for brain scans. RESULTS 83% (89/107) of involved individuals returned questionnaires. The most common discomfort among 31 children receiving 3 T MRI was noisiness (39%), followed by cold (19%), general discomfort (16%), dizziness (13%) and claustrophobia (10%). The noise was reported more frequently in children younger than 12 years than those older (p=0.021). The most common discomfort for 58 adults receiving 7 T MRI was noisiness (43%). In adults, there was a higher frequency of general discomfort during 7 than 3 T scans (p=0.031). More than 85% of adult respondents thought children aged 12-17 years would tolerate 7 T scans well, but only 35% and 15% thought children aged 10-11 and 8-9 years, respectively, would. CONCLUSIONS Noisiness was the most common discomfort across all ages in 3 and 7 T scanners. Although general discomfort was more common during 7 than 3 T scans in adults, most adults thought children aged 12 years or more would tolerate 7 T MRI well. Cautious enrolment of children in 7 T MRI study is warranted, but until there is more evidence of how well those aged 12 years or more tolerate 7 T MRI, we would caution against enrolling younger children.
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Affiliation(s)
- I-Jun Chou
- Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK
- Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
- Division of Paediatric Neurology and Paediatric General Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Christopher R Tench
- Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK
| | - Penny Gowland
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Tim Jaspan
- Department of Radiology, Nottingham University Hospitals Trust, Nottingham, UK
| | - Rob A Dineen
- Department of Radiology, Nottingham University Hospitals Trust, Nottingham, UK
- Division of Radiological and Imaging Sciences, University of Nottingham, Nottingham, UK
| | - Nikos Evangelou
- Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK
| | - Rasha Abdel-Fahim
- Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK
| | - William P Whitehouse
- Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
- Department of Paediatric Neurology, Nottingham Children's Hospital, Nottingham University Hospitals Trust, Nottingham, UK
| | - Cris S Constantinescu
- Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK
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van der Jagt MA, Brink WM, Versluis MJ, Steens SCA, Briaire JJ, Webb AG, Frijns JHM, Verbist BM. Visualization of human inner ear anatomy with high-resolution MR imaging at 7T: initial clinical assessment. AJNR Am J Neuroradiol 2014; 36:378-83. [PMID: 25147195 DOI: 10.3174/ajnr.a4084] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE In many centers, MR imaging of the inner ear and auditory pathway performed on 1.5T or 3T systems is part of the preoperative work-up of cochlear implants. We investigated the applicability of clinical inner ear MR imaging at 7T and compared the visibility of inner ear structures and nerves within the internal auditory canal with images acquired at 3T. MATERIALS AND METHODS Thirteen patients with sensorineural hearing loss eligible for cochlear implantation underwent examinations on 3T and 7T scanners. Two experienced head and neck radiologists evaluated the 52 inner ear datasets. Twenty-four anatomic structures of the inner ear and 1 overall score for image quality were assessed by using a 4-point grading scale for the degree of visibility. RESULTS The visibility of 11 of the 24 anatomic structures was rated higher on the 7T images. There was no significant difference in the visibility of 13 anatomic structures and the overall quality rating. A higher incidence of artifacts was observed in the 7T images. CONCLUSIONS The gain in SNR at 7T yielded a more detailed visualization of many anatomic structures, especially delicate ones, despite the challenges accompanying MR imaging at a high magnetic field.
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Affiliation(s)
- M A van der Jagt
- From the Departments of Otorhinolaryngology (M.A.v.d.J., J.J.B., J.H.M.F.)
| | - W M Brink
- Radiology (W.M.B., M.J.V., A.G.W., B.M.V.) C.J. Gorter Center for High-Field MRI (W.M.B., M.J.V., A.G.W.)
| | - M J Versluis
- Radiology (W.M.B., M.J.V., A.G.W., B.M.V.) C.J. Gorter Center for High-Field MRI (W.M.B., M.J.V., A.G.W.)
| | - S C A Steens
- Department of Radiology (S.C.A.S., B.M.V.), Radboud University Medical Center, Nijmegen, the Netherlands
| | - J J Briaire
- From the Departments of Otorhinolaryngology (M.A.v.d.J., J.J.B., J.H.M.F.)
| | - A G Webb
- Radiology (W.M.B., M.J.V., A.G.W., B.M.V.) C.J. Gorter Center for High-Field MRI (W.M.B., M.J.V., A.G.W.)
| | - J H M Frijns
- From the Departments of Otorhinolaryngology (M.A.v.d.J., J.J.B., J.H.M.F.) Leiden Institute for Brain and Cognition (J.H.M.F.), Leiden University Medical Center, Leiden, the Netherlands
| | - B M Verbist
- Radiology (W.M.B., M.J.V., A.G.W., B.M.V.) Department of Radiology (S.C.A.S., B.M.V.), Radboud University Medical Center, Nijmegen, the Netherlands
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Short-term side-effects of brain MR examination at 7 T: a single-centre experience. Eur Radiol 2014; 24:1923-8. [PMID: 24816933 DOI: 10.1007/s00330-014-3177-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 04/03/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To study patient tolerability of brain imaging that employs an ultrahigh field (7 T) MR system METHODS We examined 180 subjects that underwent brain MR examination at 7 T. A tolerability test consisting of two parts (during patient table motion and during the examination) was administered to all subjects in order to monitor their discomfort. The scores range from 0 to 5 for the first part, and from 0 to 10 for the second part, the total score of each subject therefore ranging from 0 (no side effects reported) to 15 (lowest tolerability) RESULTS A total of 51% of subjects reported at least one side effect but all were mild in intensity and did not require examination interruption. No serious adverse event was reported. The total score (mean ± standard deviation) was 1.1 ± 1.5 out of 15 (mean score 0.4 ± 0.7 out of 5 during patient table motion and 0.7 ± 1.1 out of 10 during MR). Patient discomfort was not related to gender or health status, but it was reduced with time after system installation with increasing operator experience in performing UHF MR examinations. CONCLUSIONS Ultrahigh field MRI is well tolerated without excessive discomfort to subjects. KEY POINTS • 7-T MRI is well tolerated with low incidence of side effects • The subjects' discomfort during 7-T MRI is reduced as the operators' experience increases • 7-T MRI is practicable in healthy subjects and patients with neurodegenerative diseases.
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Multicenter Study of Subjective Acceptance During Magnetic Resonance Imaging at 7 and 9.4 T. Invest Radiol 2014; 49:249-59. [DOI: 10.1097/rli.0000000000000035] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Schaap K, Christopher-de Vries Y, Mason CK, de Vocht F, Portengen L, Kromhout H. Occupational exposure of healthcare and research staff to static magnetic stray fields from 1.5-7 Tesla MRI scanners is associated with reporting of transient symptoms. Occup Environ Med 2014; 71:423-9. [PMID: 24714654 PMCID: PMC4033112 DOI: 10.1136/oemed-2013-101890] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Objectives Limited data is available about incidence of acute transient symptoms associated with occupational exposure to static magnetic stray fields from MRI scanners. We aimed to assess the incidence of these symptoms among healthcare and research staff working with MRI scanners, and their association with static magnetic field exposure. Methods We performed an observational study among 361 employees of 14 clinical and research MRI facilities in The Netherlands. Each participant completed a diary during one or more work shifts inside and/or outside the MRI facility, reporting work activities and symptoms (from a list of potentially MRI-related symptoms, complemented with unrelated symptoms) experienced during a working day. We analysed 633 diaries. Exposure categories were defined by strength and type of MRI scanner, using non-MRI shifts as the reference category for statistical analysis. Non-MRI shifts originated from MRI staff who also participated on MRI days, as well as CT radiographers who never worked with MRI. Results Varying per exposure category, symptoms were reported during 16–39% of the MRI work shifts. We observed a positive association between scanner strength and reported symptoms among healthcare and research staff working with closed-bore MRI scanners of 1.5 Tesla (T) and higher (1.5 T OR=1.88; 3.0 T OR=2.14; 7.0 T OR=4.17). This finding was mainly driven by reporting of vertigo and metallic taste. Conclusions The results suggest an exposure-response association between exposure to strong static magnetic fields (and associated motion-induced time-varying magnetic fields) and reporting of transient symptoms on the same day of exposure. Trial registration number 11-032/C
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Affiliation(s)
- Kristel Schaap
- Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
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Theysohn JM, Kraff O, Eilers K, Andrade D, Gerwig M, Timmann D, Schmitt F, Ladd ME, Ladd SC, Bitz AK. Vestibular effects of a 7 Tesla MRI examination compared to 1.5 T and 0 T in healthy volunteers. PLoS One 2014; 9:e92104. [PMID: 24658179 PMCID: PMC3962400 DOI: 10.1371/journal.pone.0092104] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 02/18/2014] [Indexed: 11/18/2022] Open
Abstract
Ultra-high-field MRI (7 Tesla (T) and above) elicits more temporary side-effects compared to 1.5 T and 3 T, e.g. dizziness or “postural instability” even after exiting the scanner. The current study aims to assess quantitatively vestibular performance before and after exposure to different MRI scenarios at 7 T, 1.5 T and 0 T. Sway path and body axis rotation (Unterberger's stepping test) were quantitatively recorded in a total of 46 volunteers before, 2 minutes after, and 15 minutes after different exposure scenarios: 7 T head MRI (n = 27), 7 T no RF (n = 22), 7 T only B0 (n = 20), 7 T in & out B0 (n = 20), 1.5 T no RF (n = 20), 0 T (n = 15). All exposure scenarios lasted 30 minutes except for brief one minute exposure in 7 T in & out B0. Both measures were documented utilizing a 3D ultrasound system. During sway path evaluation, the experiment was repeated with eyes both open and closed. Sway paths for all long-lasting 7 T scenarios (normal, no RF, only B0) with eyes closed were significantly prolonged 2 minutes after exiting the scanner, normalizing after 15 minutes. Brief exposure to 7 T B0 or 30 minutes exposure to 1.5 T or 0 T did not show significant changes. End positions after Unterberger's stepping test were significantly changed counter-clockwise after all 7 T scenarios, including the brief in & out B0 exposure. Shorter exposure resulted in a smaller alteration angle. In contrast to sway path, reversal of changes in body axis rotation was incomplete after 15 minutes. 1.5 T caused no rotational changes. The results show that exposure to the 7 Tesla static magnetic field causes only a temporary dysfunction or “over-compensation” of the vestibular system not measurable at 1.5 or 0 Tesla. Radiofrequency fields, gradient switching, and orthostatic dysregulation do not seem to play a role.
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Affiliation(s)
- Jens M. Theysohn
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
- Institute for Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
- * E-mail:
| | - Oliver Kraff
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
- Institute for Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - Kristina Eilers
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
- Institute for Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - Dorian Andrade
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
- Institute for Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - Marcus Gerwig
- Department of Neurology, University Hospital Essen, Essen, Germany
| | - Dagmar Timmann
- Department of Neurology, University Hospital Essen, Essen, Germany
| | | | - Mark E. Ladd
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
- Division of Medical Physics in Radiology (E020), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Susanne C. Ladd
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
- Institute for Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - Andreas K. Bitz
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany
- Division of Medical Physics in Radiology (E020), German Cancer Research Center (DKFZ), Heidelberg, Germany
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Barochiner J, Aparicio LS, Waisman GD. Challenges associated with peripheral arterial disease in women. Vasc Health Risk Manag 2014; 10:115-28. [PMID: 24648743 PMCID: PMC3956880 DOI: 10.2147/vhrm.s45181] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Peripheral arterial disease (PAD) is an increasingly recognized disorder that is associated with functional impairment, quality-of-life deterioration, increased risk of cardiovascular ischemic events, and increased risk of total and cardiovascular mortality. Although earlier studies suggested that PAD was more common in men, recent reports based on more sensitive tests have shown that the prevalence of PAD in women is at least the same as in men, if not higher. PAD tends to present itself asymptomatically or with atypical symptoms more frequently in women than in men, and is associated with comorbidities or situations particularly or exclusively found in the female sex, such as osteoporosis, hypothyroidism, the use of oral contraceptives, and a history of complications during pregnancy. Fat-distribution patterns and differential vascular characteristics in women may influence the interpretation of diagnostic methods, whereas sex-related vulnerability to drugs typically used in subjects with PAD, differences in risk-factor distribution among sexes, and distinct responses to revascularization procedures in men and women must be taken into account for proper disease management. All these issues pose important challenges associated with PAD in women. Of note, this group has classically been underrepresented in research studies. As a consequence, several sex-related challenges regarding diagnosis and management issues should be acknowledged, and research gaps should be addressed in order to successfully deal with this major health issue.
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Affiliation(s)
- Jessica Barochiner
- Hypertension Section, Internal Medicine Department, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - Lucas S Aparicio
- Hypertension Section, Internal Medicine Department, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - Gabriel D Waisman
- Hypertension Section, Internal Medicine Department, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
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Mian OS, Li Y, Antunes A, Glover PM, Day BL. On the vertigo due to static magnetic fields. PLoS One 2013; 8:e78748. [PMID: 24205304 PMCID: PMC3813712 DOI: 10.1371/journal.pone.0078748] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Accepted: 09/20/2013] [Indexed: 12/03/2022] Open
Abstract
Vertigo is sometimes experienced in and around MRI scanners. Mechanisms involving stimulation of the vestibular system by movement in magnetic fields or magnetic field spatial gradients have been proposed. However, it was recently shown that vestibular-dependent ocular nystagmus is evoked when stationary in homogenous static magnetic fields. The proposed mechanism involves Lorentz forces acting on endolymph to deflect semicircular canal (SCC) cupulae. To investigate whether vertigo arises from a similar mechanism we recorded qualitative and quantitative aspects of vertigo and 2D eye movements from supine healthy adults (n = 25) deprived of vision while pushed into the 7T static field of an MRI scanner. Exposures were variable and included up to 135s stationary at 7T. Nystagmus was mainly horizontal, persisted during long-exposures with partial decline, and reversed upon withdrawal. The dominant vertiginous perception with the head facing up was rotation in the horizontal plane (85% incidence) with a consistent direction across participants. With the head turned 90 degrees in yaw the perception did not transform into equivalent vertical plane rotation, indicating a context-dependency of the perception. During long exposures, illusory rotation lasted on average 50 s, including 42 s whilst stationary at 7T. Upon withdrawal, perception re-emerged and reversed, lasting on average 30 s. Onset fields for nystagmus and perception were significantly correlated (p<.05). Although perception did not persist as long as nystagmus, this is a known feature of continuous SSC stimulation. These observations, and others in the paper, are compatible with magnetic-field evoked-vertigo and nystagmus sharing a common mechanism. With this interpretation, response decay and reversal upon withdrawal from the field, are due to adaptation to continuous vestibular input. Although the study does not entirely exclude the possibility of mechanisms involving transient vestibular stimulation during movement in and out of the bore, we argue these are less likely.
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Affiliation(s)
- Omar S. Mian
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Yan Li
- Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, United Kingdom
| | - Andre Antunes
- Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, United Kingdom
| | - Paul M. Glover
- Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, United Kingdom
| | - Brian L. Day
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
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