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Peña-Trujillo V, Gallo-Bernal S, Kirsch J, Victoria T, Gee MS. 3 Tesla Fetal MR Imaging Quality and Safety Considerations. Magn Reson Imaging Clin N Am 2024; 32:385-394. [PMID: 38944429 DOI: 10.1016/j.mric.2024.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2024]
Abstract
Medical imaging, particularly fetal MR imaging, has undergone a transformative shift with the introduction of 3 Tesla (3T) clinical MR imaging systems. The utilization of higher static magnetic fields in these systems has resulted in remarkable advancements, including superior soft tissue contrast, improved spatial and temporal resolution, and reduced image acquisition time. Despite these notable benefits, safety concerns have emerged, stemming from the elevated static magnetic field strength, amplified acoustic noise, and increased radiofrequency power deposition. This article provides an overview of fetal MR imaging at 3T, its benefits and drawbacks, and the potential safety issues.
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Affiliation(s)
- Valeria Peña-Trujillo
- Department of Radiology, Massachusetts General Hospital, 55 Fruit Strret, Boston, MA 02114, USA; Department of Radiology, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA; Pediatric Imaging Research Center (PIRC), Massachusetts General Hospital, 55 Fruit Strret, Boston, MA 02114, USA
| | - Sebastian Gallo-Bernal
- Department of Radiology, Massachusetts General Hospital, 55 Fruit Strret, Boston, MA 02114, USA; Department of Radiology, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA; Pediatric Imaging Research Center (PIRC), Massachusetts General Hospital, 55 Fruit Strret, Boston, MA 02114, USA; Department of Medicine, NYC Health + Hospitals/Queens, Icahn School of Medicine at Mount Sinai, 79-01 Broadway, Queens, NY 11373, USA
| | - John Kirsch
- Department of Radiology, Massachusetts General Hospital, 55 Fruit Strret, Boston, MA 02114, USA; Department of Radiology, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA; A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, 149 13th, Chartlestown, MA 02129, USA
| | - Teresa Victoria
- Department of Radiology, Massachusetts General Hospital, 55 Fruit Strret, Boston, MA 02114, USA; Department of Radiology, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA; Pediatric Imaging Research Center (PIRC), Massachusetts General Hospital, 55 Fruit Strret, Boston, MA 02114, USA
| | - Michael S Gee
- Department of Radiology, Massachusetts General Hospital, 55 Fruit Strret, Boston, MA 02114, USA; Department of Radiology, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA; Pediatric Imaging Research Center (PIRC), Massachusetts General Hospital, 55 Fruit Strret, Boston, MA 02114, USA.
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Ní Leidhin C, Erickson JP, Bynevelt M, Lam G, Lock JH, Wang G, Mankad K, Taranath A, Mason M, Lakshmanan R, Shipman P, Warne RR. (What's the story) morning glory? MRI findings in morning glory disc anomaly. Neuroradiology 2024; 66:1225-1233. [PMID: 38717474 DOI: 10.1007/s00234-024-03375-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 05/01/2024] [Indexed: 06/05/2024]
Abstract
PURPOSE Morning glory disc anomaly (MGDA) is a rare congenital ophthalmologic disorder. Historically it has been diagnosed fundoscopically, with little in the literature regarding its imaging findings. The purpose of this study is to further characterize the orbital and associated intracranial magnetic resonance imaging (MRI) findings of MGDA in our tertiary pediatric center. METHODS A retrospective review was performed of fundoscopically-diagnosed cases of MGDA, that had been referred for MRI. All MRI studies were scrutinized for orbital and other intracranial abnormalities known to occur in association with MGDA. RESULTS 18 of 19 cases of MGDA showed three characteristic MRI findings: funnel-shaped morphology of the posterior optic disc, abnormal soft tissue associated with the retrobulbar optic nerve, and effacement of adjacent subarachnoid spaces. The ipsilateral (intraorbital) optic nerve was larger in one patient and smaller in six. The ipsilateral optic chiasm was larger in two patients and smaller in one. CONCLUSION This study represents a comprehensive radiological-led investigation into MGDA. It describes the most frequently-encountered MRI findings in MGDA and emphasizes the importance of MRI in this cohort, i.e., in distinguishing MGDA from other posterior globe abnormalities, in assessing the visual pathway, and in screening for associated intracranial abnormalities - skull base/cerebral, vascular, and facial. It hypothesizes neurocristopathy as an underlying cause of MGDA and its associations. Caliber abnormalities of the ipsilateral optic nerve and chiasm are a frequent finding in MGDA. Optic pathway enlargement should not be labeled "glioma". (239/250).
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Affiliation(s)
- Caoilfhionn Ní Leidhin
- Department of Medical Imaging, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia.
| | - Jonathan P Erickson
- Department of Medical Imaging, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
| | - Michael Bynevelt
- Department of Medical Imaging, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
| | - Geoffrey Lam
- Department of Ophthalmology, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
| | - Jane H Lock
- Department of Ophthalmology, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
| | - George Wang
- Department of Biostatistics, School of Public Health, University of Sydney, Sydney, NSW, Australia
| | - Kshitij Mankad
- Department of Paediatric Neuroradiology, Great Ormond Street Hospital for Children, London, England, UK
| | - Ajay Taranath
- Department of Medical Imaging, Women's and Children's Hospital, Adelaide, SA, Australia
| | - Michael Mason
- Department of Medical Imaging, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
| | - Rahul Lakshmanan
- Department of Medical Imaging, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
- Centre for Neuromuscular and Neurological Disorders (Perron Institute), University of Western Australia Medical School, Perth, WA, Australia
| | - Peter Shipman
- Department of Medical Imaging, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
| | - Richard R Warne
- Department of Medical Imaging, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
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Petzold J, Schmitter S, Silemek B, Winter L, Speck O, Ittermann B, Seifert F. Investigation of alternative RF power limit control methods for 0.5T, 1.5T, and 3T parallel transmission cardiac imaging: A simulation study. Magn Reson Med 2024; 91:1659-1675. [PMID: 38031517 DOI: 10.1002/mrm.29932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 10/09/2023] [Accepted: 10/31/2023] [Indexed: 12/01/2023]
Abstract
PURPOSE To investigate safety and performance aspects of parallel-transmit (pTx) RF control-modes for a body coil atB 0 ≤ 3 T $$ {B}_0\le 3\mathrm{T} $$ . METHODS Electromagnetic simulations of 11 human voxel models in cardiac imaging position were conducted forB 0 = 0.5 T $$ {B}_0=0.5\mathrm{T} $$ ,1.5 T $$ 1.5\mathrm{T} $$ and3 T $$ 3\mathrm{T} $$ and a body coil with a configurable number of transmit channels (1, 2, 4, 8, 16). Three safety modes were considered: the 'SAR-controlled mode' (SCM), where specific absorption rate (SAR) is limited directly, a 'phase agnostic SAR-controlled mode' (PASCM), where phase information is neglected, and a 'power-controlled mode' (PCM), where the voltage amplitude for each channel is limited. For either mode, safety limits were established based on a set of 'anchor' simulations and then evaluated in 'target' simulations on previously unseen models. The comparison allowed to derive safety factors accounting for varying patient anatomies. All control modes were compared in terms of theB 1 + $$ {B}_1^{+} $$ amplitude and homogeneity they permit under their respective safety requirements. RESULTS Large safety factors (approximately five) are needed if only one or two anchor models are investigated but they shrink with increasing number of anchors. The achievableB 1 + $$ {B}_1^{+} $$ is highest for SCM but this advantage is reduced when the safety factor is included. PCM appears to be more robust against variations of subjects. PASCM performance is mostly in between SCM and PCM. Compared to standard circularly polarized (CP) excitation, pTx offers minorB 1 + $$ {B}_1^{+} $$ improvements if local SAR limits are always enforced. CONCLUSION PTx body coils can safely be used atB 0 ≤ 3 T $$ {B}_0\le 3\mathrm{T} $$ . Uncertainties in patient anatomy must be accounted for, however, by simulating many models.
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Affiliation(s)
- Johannes Petzold
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
- Biomedical Magnetic Resonance, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Sebastian Schmitter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Berk Silemek
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Lukas Winter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Oliver Speck
- Biomedical Magnetic Resonance, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Bernd Ittermann
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Frank Seifert
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
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Kligerman S. Cardiac MRI Field Strength: Point-If I Could Only Have a Single MRI System, Why I Would Opt for a 1.5-T Scanner Over a 3-T Scanner. AJR Am J Roentgenol 2024; 222:e2330097. [PMID: 37729553 DOI: 10.2214/ajr.23.30097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Affiliation(s)
- Seth Kligerman
- Department of Diagnostic Radiology, National Jewish Health, 1400 Jackson St, Denver, CO 80206
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Ong SJ, Hallinan JTPD, Khoo D, Hoon D, Chia KL, Hang J, Teo L, Su P, Ong M, Ang B, Quek ST. Local cOinage and Hospital Equipment Index (Lo Hei): projectile distance of Singapore coinage and healthcare-related equipment in a 3T magnetic resonance imaging scanner. Singapore Med J 2024; 65:61-67. [PMID: 38343123 PMCID: PMC10942138 DOI: 10.4103/singaporemedj.smj-2024-007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Accepted: 01/19/2024] [Indexed: 02/15/2024]
Abstract
INTRODUCTION Modern magnetic resonance imaging (MRI) scanners utilise superconducting magnets that are permanently active. Patients and healthcare professionals have been known to unintentionally introduce ferromagnetic objects into the scanning room. In this study, we evaluated the projectile risk of Singapore coinage as well as some common healthcare equipment within a 3 T MRI scanner. METHODS A rig termed 'Object eNtry Guidance and Linear Acceleration Instrument' (ONG LAI) was custom-built to facilitate safe trajectory of the putative ferromagnetic objects. A ballistic gel target was utilised as a human tissue surrogate to estimate tissue penetration. The point at which objects would self-propel towards the scanner was named 'Huge Unintended Acceleration Towards Actual Harm (HUAT AH)'. RESULTS Singapore third-series coins (10-cent to 1-dollar coins) are highly ferromagnetic and would accelerate towards the MRI scanner from more than one metre away. Cannulas with their needles are ferromagnetic and would self-propel towards the scanner from a distance of 20 cm. Standard surgical masks are ferromagnetic and may lose their sealing efficacy when they are worn too close to the magnet. Among the tested objects, a can of pineapple drink (Lee Pineapple Juice) had the highest HUAT AH at a distance of more than 1.5 m. CONCLUSION Some local coinage and commonly found objects within a healthcare setting demonstrate ferromagnetic activity with projectile potential from a distance of more than 1 m. Patients and healthcare professionals should be cognisant of the risk associated with introducing these objects into the MRI scanning room.
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Affiliation(s)
- Shao Jin Ong
- Department of Diagnostic Imaging, National University Hospital, Singapore
- Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - James TPD Hallinan
- Department of Diagnostic Imaging, National University Hospital, Singapore
- Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Deborah Khoo
- Department of Anaesthesia, National University Hospital, Singapore
| | - Desmond Hoon
- Department of Diagnostic Imaging, National University Hospital, Singapore
| | - Koon Liang Chia
- Department of Diagnostic Imaging, National University Hospital, Singapore
| | - Joanne Hang
- Department of Diagnostic Imaging, National University Hospital, Singapore
| | - Lycia Teo
- Department of Psychiatry, Ng Teng Fong General Hospital, Singapore
| | - Peijing Su
- Division of Rehabilitation Medicine, Department of Medicine, National University Hospital, Singapore
| | - Michael Ong
- Centre for Health Professionals Training, National University Health Systems, Singapore
| | - Bertrand Ang
- Department of Diagnostic Imaging, National University Hospital, Singapore
- Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Swee Tian Quek
- Department of Diagnostic Imaging, National University Hospital, Singapore
- Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Tian Y, Nayak KS. New clinical opportunities of low-field MRI: heart, lung, body, and musculoskeletal. MAGMA (NEW YORK, N.Y.) 2024; 37:1-14. [PMID: 37902898 PMCID: PMC10876830 DOI: 10.1007/s10334-023-01123-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 09/28/2023] [Accepted: 10/05/2023] [Indexed: 11/01/2023]
Abstract
Contemporary whole-body low-field MRI scanners (< 1 T) present new and exciting opportunities for improved body imaging. The fundamental reason is that the reduced off-resonance and reduced SAR provide substantially increased flexibility in the design of MRI pulse sequences. Promising body applications include lung parenchyma imaging, imaging adjacent to metallic implants, cardiac imaging, and dynamic imaging in general. The lower cost of such systems may make MRI favorable for screening high-risk populations and population health research, and the more open configurations allowed may prove favorable for obese subjects and for pregnant women. This article summarizes promising body applications for contemporary whole-body low-field MRI systems, with a focus on new platforms developed within the past 5 years. This is an active area of research, and one can expect many improvements as MRI physicists fully explore the landscape of pulse sequences that are feasible, and as clinicians apply these to patient populations.
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Affiliation(s)
- Ye Tian
- Ming Hsieh Department of Electrical and Computer Engineering, Viterbi School of Engineering, University of Southern California, 3740 McClintock Ave, EEB 406, Los Angeles, CA, 90089-2564, USA.
| | - Krishna S Nayak
- Ming Hsieh Department of Electrical and Computer Engineering, Viterbi School of Engineering, University of Southern California, 3740 McClintock Ave, EEB 406, Los Angeles, CA, 90089-2564, USA
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Ong SJ, Chia KL, See TC, Graves M, Hoon D, Hang J, Teo L, Su P, Hallinan JTPD, Ong M, Ang B, Quek ST. Common Healthcare Related Instruments Subjected To Magnetic Attraction Study (CHRISTMAS): prospective in situ experimental study. BMJ 2023; 383:e077164. [PMID: 38128958 PMCID: PMC10739172 DOI: 10.1136/bmj-2023-077164] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/27/2023] [Indexed: 12/23/2023]
Abstract
OBJECTIVE To investigate the behaviour of common healthcare related objects in a 3 tesla (T) MRI (magnetic resonance imaging) scanner, examining their ability to self-propel towards the scanner bore and their potential for tissue penetration. DESIGN Prospective in situ experimental study. SETTING Clinical 3 T MRI scanner. Customised rig designed and built to guide objects towards the scanner bore. PARTICIPANTS 12 categories of objects commonly found in hospitals, or on patients or healthcare professionals, or near an MRI scanning room. Human tissue penetration simulated with ballistic gel (Federal Bureau of Investigation and North Atlantic Treaty Organisation graded). MAIN OUTCOME MEASURES SANTA (site where applied newtonian mechanics triggers acceleration) measurements and depth of tissue penetration of the objects. RESULTS SANTA measurements ranged from 0 cm for the 20 pence, 50 pence, and £2 coins to 152-161 cm for a knife and the biscuit tins. One penny, two pence, five pence, and 10 pence coins showed self-propulsion and acceleration towards the scanner bore at a distance >100 cm from the gantry entry point. Linear regression analysis showed no apparent correlation between the weight of the objects and their SANTA measurements (R2<0.1). Only five objects penetrated the ballistic gel (simulated human tissue). The deepest penetration was by the knife (5.5 cm), closely followed by the teaspoon (5.0 cm), fork (4.0 cm), spoon (3.5 cm), and a 10 pence coin (0.5 cm). Although the biscuit tins did not penetrate the simulated human tissue, they exerted substantial impact force which could potentially cause bone fractures. A smartphone, digital thermometer, metallic credit card, and pen torch remained fully functional after several passes into the MRI scanner. No discernible loss of image quality for the MRI scanner after the experiments was found. CONCLUSIONS The study highlights the potential for harm (major tissue damage and bone fractures) when commonly found objects in a healthcare setting are unintentionally brought into the MRI scanner room. Patients and healthcare professionals need to be aware of the dangers associated with bringing ferromagnetic objects into the MRI environment.
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Affiliation(s)
- Shao J Ong
- Department of Diagnostic Imaging, National University Hospital, Singapore 119074, Singapore
- Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Koon Liang Chia
- Department of Diagnostic Imaging, National University Hospital, Singapore 119074, Singapore
| | - Teik Choon See
- Department of Radiology, Cambridge University Hospitals, NHS Foundation Trust, Cambridge, UK
- Department of Radiology, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, UK
| | - Martin Graves
- Department of Radiology, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, UK
| | - Desmond Hoon
- Department of Diagnostic Imaging, National University Hospital, Singapore 119074, Singapore
| | - Joanne Hang
- Department of Diagnostic Imaging, National University Hospital, Singapore 119074, Singapore
| | - Lycia Teo
- Department of Psychiatry, Ng Teng Fong General Hospital, Singapore
| | - Peijing Su
- Division of Rehabilitation Medicine, Department of Medicine, National University Hospital, Singapore
| | - James T P D Hallinan
- Department of Diagnostic Imaging, National University Hospital, Singapore 119074, Singapore
- Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Michael Ong
- Centre for Health Professionals Training (CHPT), National University Health Systems, Singapore
| | - Bertrand Ang
- Department of Diagnostic Imaging, National University Hospital, Singapore 119074, Singapore
- Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Swee Tian Quek
- Department of Diagnostic Imaging, National University Hospital, Singapore 119074, Singapore
- Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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