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Perera Molligoda Arachchige AS, Politi LS. Potential applications of 7 Tesla magnetic resonance imaging in paediatric neuroimaging: Feasibility and challenges. World J Clin Pediatr 2024; 13:90641. [PMID: 38947986 PMCID: PMC11212755 DOI: 10.5409/wjcp.v13.i2.90641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 01/23/2024] [Accepted: 04/02/2024] [Indexed: 06/07/2024] Open
Abstract
The integration of 7 Tesla magnetic resonance imaging (7 T MRI) in adult patients has marked a revolutionary stride in radiology. In this article we explore the feasibility of 7 T MRI in paediatric practice, emphasizing its feasibility, applications, challenges, and safety considerations. The heightened resolution and tissue contrast of 7 T MRI offer unprecedented diagnostic accuracy, particularly in neuroimaging. Applications range from neuro-oncology to neonatal brain imaging, showcasing its efficacy in detecting subtle structural abnormalities and providing enhanced insights into neurological conditions. Despite the promise, challenges such as high cost, discomfort, and safety concerns necessitate careful consideration. Research suggests that, with precautions, 7 T MRI is feasible in paediatrics, yet ongoing studies and safety assessments are imperative.
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Affiliation(s)
| | - Letterio S Politi
- Department of Neuroradiology, IRCCS Humanitas Research Hospital, Rozzano 20089, Milan, Italy
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele 20072, Milan, Italy
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2
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Bridgen P, Tomi-Tricot R, Uus A, Cromb D, Quirke M, Almalbis J, Bonse B, De la Fuente Botella M, Maggioni A, Cio PD, Cawley P, Casella C, Dokumaci AS, Thomson AR, Willers Moore J, Bridglal D, Saravia J, Finck T, Price AN, Pickles E, Cordero-Grande L, Egloff A, O’Muircheartaigh J, Counsell SJ, Giles SL, Deprez M, De Vita E, Rutherford MA, Edwards AD, Hajnal JV, Malik SJ, Arichi T. High resolution and contrast 7 tesla MR brain imaging of the neonate. FRONTIERS IN RADIOLOGY 2024; 3:1327075. [PMID: 38304343 PMCID: PMC10830693 DOI: 10.3389/fradi.2023.1327075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 12/29/2023] [Indexed: 02/03/2024]
Abstract
Introduction Ultra-high field MR imaging offers marked gains in signal-to-noise ratio, spatial resolution, and contrast which translate to improved pathological and anatomical sensitivity. These benefits are particularly relevant for the neonatal brain which is rapidly developing and sensitive to injury. However, experience of imaging neonates at 7T has been limited due to regulatory, safety, and practical considerations. We aimed to establish a program for safely acquiring high resolution and contrast brain images from neonates on a 7T system. Methods Images were acquired from 35 neonates on 44 occasions (median age 39 + 6 postmenstrual weeks, range 33 + 4 to 52 + 6; median body weight 2.93 kg, range 1.57 to 5.3 kg) over a median time of 49 mins 30 s. Peripheral body temperature and physiological measures were recorded throughout scanning. Acquired sequences included T2 weighted (TSE), Actual Flip angle Imaging (AFI), functional MRI (BOLD EPI), susceptibility weighted imaging (SWI), and MR spectroscopy (STEAM). Results There was no significant difference between temperature before and after scanning (p = 0.76) and image quality assessment compared favorably to state-of-the-art 3T acquisitions. Anatomical imaging demonstrated excellent sensitivity to structures which are typically hard to visualize at lower field strengths including the hippocampus, cerebellum, and vasculature. Images were also acquired with contrast mechanisms which are enhanced at ultra-high field including susceptibility weighted imaging, functional MRI, and MR spectroscopy. Discussion We demonstrate safety and feasibility of imaging vulnerable neonates at ultra-high field and highlight the untapped potential for providing important new insights into brain development and pathological processes during this critical phase of early life.
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Affiliation(s)
- Philippa Bridgen
- LondonCollaborative Ultra High Field System (LoCUS), King’s College London, London, United Kingdom
- Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - Raphael Tomi-Tricot
- LondonCollaborative Ultra High Field System (LoCUS), King’s College London, London, United Kingdom
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- MR Research Collaborations, Siemens Healthcare Limited, London, United Kingdom
| | - Alena Uus
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Daniel Cromb
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Megan Quirke
- Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Jennifer Almalbis
- Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Beya Bonse
- Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Miguel De la Fuente Botella
- Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Alessandra Maggioni
- Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Pierluigi Di Cio
- LondonCollaborative Ultra High Field System (LoCUS), King’s College London, London, United Kingdom
- Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - Paul Cawley
- Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Chiara Casella
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Ayse Sila Dokumaci
- Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Alice R. Thomson
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- MRC Centre for Neurodevelopmental Disorders, King’s College London, London, United Kingdom
| | - Jucha Willers Moore
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- MRC Centre for Neurodevelopmental Disorders, King’s College London, London, United Kingdom
| | - Devi Bridglal
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Joao Saravia
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Thomas Finck
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Anthony N. Price
- Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Elisabeth Pickles
- LondonCollaborative Ultra High Field System (LoCUS), King’s College London, London, United Kingdom
- Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom
- Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Lucilio Cordero-Grande
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- Biomedical Image Technologies, ETSI Telecomunicación, Universidad Politécnica de Madrid and CIBER-BBN, ISCIII, Madrid, Spain
| | - Alexia Egloff
- Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Jonathan O’Muircheartaigh
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- MRC Centre for Neurodevelopmental Disorders, King’s College London, London, United Kingdom
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
| | - Serena J. Counsell
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Sharon L. Giles
- LondonCollaborative Ultra High Field System (LoCUS), King’s College London, London, United Kingdom
- Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom
- Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Maria Deprez
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Enrico De Vita
- LondonCollaborative Ultra High Field System (LoCUS), King’s College London, London, United Kingdom
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- MR Physics, Radiology Department, Great Ormond Street Hospital for Children, London, United Kingdom
| | - Mary A. Rutherford
- Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- MRC Centre for Neurodevelopmental Disorders, King’s College London, London, United Kingdom
| | - A. David Edwards
- Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- MRC Centre for Neurodevelopmental Disorders, King’s College London, London, United Kingdom
| | - Joseph V. Hajnal
- LondonCollaborative Ultra High Field System (LoCUS), King’s College London, London, United Kingdom
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Shaihan J. Malik
- LondonCollaborative Ultra High Field System (LoCUS), King’s College London, London, United Kingdom
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Tomoki Arichi
- Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom
- Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- MRC Centre for Neurodevelopmental Disorders, King’s College London, London, United Kingdom
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3
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Moser J, Koirala S, Madison T, Labonte AK, Carrasco CM, Feczko E, Moore LA, Ahmed W, Myers MJ, Yacoub E, Trevo-Clemmens B, Larsen B, Laumann TO, Nelson SM, Vizioli L, Sylvester CM, Fair DA. Multi-echo Acquisition and Thermal Denoising Advances Infant Precision Functional Imaging. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.27.564416. [PMID: 37961636 PMCID: PMC10634909 DOI: 10.1101/2023.10.27.564416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The characterization of individual functional brain organization with Precision Functional Mapping has provided important insights in recent years in adults. However, little is known about the ontogeny of inter-individual differences in brain functional organization during human development, but precise characterization of systems organization during periods of high plasticity might be most influential towards discoveries promoting lifelong health. Collecting and analyzing precision fMRI data during early development has unique challenges and emphasizes the importance of novel methods to improve data acquisition, processing, and analysis strategies in infant samples. Here, we investigate the applicability of two such methods from adult MRI research, multi-echo (ME) data acquisition and thermal noise removal with Noise reduction with distribution corrected principal component analysis (NORDIC), in precision fMRI data from three newborn infants. Compared to an adult example subject, T2* relaxation times calculated from ME data in infants were longer and more variable across the brain, pointing towards ME acquisition being a promising tool for optimizing developmental fMRI. The application of thermal denoising via NORDIC increased tSNR and the overall strength of functional connections as well as the split-half reliability of functional connectivity matrices in infant ME data. While our findings related to NORDIC denoising are coherent with the adult literature and ME data acquisition showed high promise, its application in developmental samples needs further investigation. The present work reveals gaps in our understanding of the best techniques for developmental brain imaging and highlights the need for further developmentally-specific methodological advances and optimizations, towards precision functional imaging in infants.
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Affiliation(s)
- Julia Moser
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, MN, USA
- Institute of Child Development, University of Minnesota, Minneapolis, MN, USA
| | - Sanju Koirala
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, MN, USA
- Institute of Child Development, University of Minnesota, Minneapolis, MN, USA
| | - Thomas Madison
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, MN, USA
| | - Alyssa K Labonte
- Department of Psychiatry, Washington University in St. Louis, St. Louis, Missouri, USA
| | | | - Eric Feczko
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, MN, USA
| | - Lucille A Moore
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, MN, USA
| | - Weli Ahmed
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, MN, USA
| | - Michael J Myers
- Department of Psychiatry, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Essa Yacoub
- Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, USA
| | - Brenden Trevo-Clemmens
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, MN, USA
| | - Bart Larsen
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, MN, USA
| | - Timothy O Laumann
- Department of Psychiatry, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Steven M Nelson
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, MN, USA
| | - Luca Vizioli
- Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, USA
| | - Chad M Sylvester
- Department of Psychiatry, Washington University in St. Louis, St. Louis, Missouri, USA
- Department of Radiology, Washington University in St. Louis, St. Louis, Missouri, USA
- Taylor Family Institute for Innovative Research, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Damien A Fair
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, MN, USA
- Institute of Child Development, University of Minnesota, Minneapolis, MN, USA
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4
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van Ooijen I, Annink K, Benders M, Dudink J, Alderliesten T, Groenendaal F, Tataranno M, Lequin M, Hoogduin J, Visser F, Raaijmakers A, Klomp D, Wiegers E, Wijnen J, van der Aa N. Introduction of ultra-high-field MR brain imaging in infants: vital parameters, temperature and comfort. NEUROIMAGE. REPORTS 2023; 3:100175. [PMID: 38357432 PMCID: PMC10865273 DOI: 10.1016/j.ynirp.2023.100175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/19/2023] [Accepted: 05/20/2023] [Indexed: 02/16/2024]
Abstract
Background Brain MRI in infants at ultra-high-field scanners might improve diagnostic quality, but safety should be evaluated first. In our previous study, we reported simulated specific absorption rates and acoustic noise data at 7 Tesla. Methods In this study, we included twenty infants between term-equivalent age and three months of age. The infants were scanned on a 7 Tesla MRI directly after their clinically indicated 3 Tesla brain MRI scan. Vital parameters, temperature, and comfort were monitored throughout the process. Brain temperature was estimated during the MRI scans using proton MR spectroscopy. Results We found no significant differences in vital parameters, temperature, and comfort during and after 7 Tesla MRI scans, compared to 3 Tesla MRI scans. Conclusions These data confirm our hypothesis that scanning infants at 7 Tesla MRI appears to be safe and we identified no additional risks from scanning at 3 Tesla MRI.
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Affiliation(s)
- I.M. van Ooijen
- Department of Neonatology, University Medical Center Utrecht, Utrecht Brain Center, University Utrecht, Utrecht, the Netherlands
- Centre for Image Sciences, High Field MR Research, University Medical Center Utrecht, University Utrecht, Utrecht, the Netherlands
| | - K.V. Annink
- Department of Neonatology, University Medical Center Utrecht, Utrecht Brain Center, University Utrecht, Utrecht, the Netherlands
| | - M.J.N.L. Benders
- Department of Neonatology, University Medical Center Utrecht, Utrecht Brain Center, University Utrecht, Utrecht, the Netherlands
| | - J. Dudink
- Department of Neonatology, University Medical Center Utrecht, Utrecht Brain Center, University Utrecht, Utrecht, the Netherlands
| | - T. Alderliesten
- Department of Neonatology, University Medical Center Utrecht, Utrecht Brain Center, University Utrecht, Utrecht, the Netherlands
| | - F. Groenendaal
- Department of Neonatology, University Medical Center Utrecht, Utrecht Brain Center, University Utrecht, Utrecht, the Netherlands
| | - M.L. Tataranno
- Department of Neonatology, University Medical Center Utrecht, Utrecht Brain Center, University Utrecht, Utrecht, the Netherlands
| | - M.H. Lequin
- Departement of Radiology, Division of Imaging and Oncology, University Medical Center Utrecht, University Utrecht, Utrecht, the Netherlands
| | - J.M. Hoogduin
- Centre for Image Sciences, High Field MR Research, University Medical Center Utrecht, University Utrecht, Utrecht, the Netherlands
| | - F. Visser
- Centre for Image Sciences, High Field MR Research, University Medical Center Utrecht, University Utrecht, Utrecht, the Netherlands
| | - A.J.E. Raaijmakers
- Centre for Image Sciences, High Field MR Research, University Medical Center Utrecht, University Utrecht, Utrecht, the Netherlands
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - D.W.J. Klomp
- Centre for Image Sciences, High Field MR Research, University Medical Center Utrecht, University Utrecht, Utrecht, the Netherlands
| | - E.C. Wiegers
- Centre for Image Sciences, High Field MR Research, University Medical Center Utrecht, University Utrecht, Utrecht, the Netherlands
| | - J.P. Wijnen
- Centre for Image Sciences, High Field MR Research, University Medical Center Utrecht, University Utrecht, Utrecht, the Netherlands
| | - N.E. van der Aa
- Department of Neonatology, University Medical Center Utrecht, Utrecht Brain Center, University Utrecht, Utrecht, the Netherlands
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Kopanoglu E. Actual patient position versus safety models: Specific Absorption Rate implications of initial head position for Ultrahigh Field Magnetic Resonance Imaging. NMR IN BIOMEDICINE 2023; 36:e4876. [PMID: 36385447 PMCID: PMC10802886 DOI: 10.1002/nbm.4876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 10/20/2022] [Accepted: 11/13/2022] [Indexed: 06/16/2023]
Abstract
Specific absorption rate (SAR) relates power absorption to tissue heating, and therefore is used as a safety constraint in magnetic resonance imaging (MRI). This study investigates the implications of initial head positioning on local and whole-head SAR. A virtual body model was simulated at 161 positions inside an eight-channel parallel-transmit (pTx) array. On-axis displacements and rotations of up to 20 mm/degrees and off-axis axial/coronal translations were investigated. Single-channel, radiofrequency (RF) shimming (i.e., single-spoke pTx) and multispoke pTx pulses were designed for seven axial, five coronal and five sagittal slices at each position (the slices were consistent across all positions). Whole-head and local SAR were calculated using safety models consisting of a single (centred) body position, multiple representative positions and all simulated body positions. Positional mismatches between safety models and actual positions cause SAR underestimation. For axial imaging, the actual peak local SAR was up to 4.2-fold higher for both single-channel and 5-spoke pTx, 3.5-fold higher for 3-/4-spoke pTx, and 2-fold higher for RF shimming and 2-spoke pTx, compared with that calculated using the centred body position. For sagittal and coronal imaging, the underestimation of peak local SAR was up to 5.2-fold and 3.8-fold, respectively. Using all body positions to estimate SAR prevented SAR underestimation but yielded up to 11-fold SAR overestimation for RF shimming. Local SAR of single-channel and pTx multispoke pulses showed considerable dependence on the initial patient position. RF shimming yielded much lower sensitivity to positional mismatches for axial imaging but not for sagittal and coronal imaging. This was deemed attributable to the higher degrees-of-freedom of control offered by the investigated coil array for axial imaging. Whole-head SAR is less sensitive to positional mismatches compared with local SAR. Nevertheless, whole-head SAR increased by up to 80% for sagittal imaging. Local and whole-head SAR were observed to be more sensitive to positional mismatches in the axial plane, because of larger variations in coil-tissue proximity. Using all possible body positions in the safety model may become substantially over-conservative and limit imaging performance, especially for the RF shimming mode for axial imaging.
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Affiliation(s)
- Emre Kopanoglu
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of PsychologyCardiff UniversityCardiffUK
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6
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Padormo F, Cawley P, Dillon L, Hughes E, Almalbis J, Robinson J, Maggioni A, Botella MDLF, Cromb D, Price A, Arlinghaus L, Pitts J, Luo T, Zhang D, Deoni SCL, Williams S, Malik S, O′Muircheartaigh J, Counsell SJ, Rutherford M, Arichi T, Edwards AD, Hajnal JV. In vivo T 1 mapping of neonatal brain tissue at 64 mT. Magn Reson Med 2023; 89:1016-1025. [PMID: 36372971 PMCID: PMC10099617 DOI: 10.1002/mrm.29509] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 09/14/2022] [Accepted: 10/11/2022] [Indexed: 11/16/2022]
Abstract
PURPOSE Ultralow-field (ULF) point-of-care MRI systems allow image acquisition without interrupting medical provision, with neonatal clinical care being an important potential application. The ability to measure neonatal brain tissue T1 is a key enabling technology for subsequent structural image contrast optimization, as well as being a potential biomarker for brain development. Here we describe an optimized strategy for neonatal T1 mapping at ULF. METHODS Examinations were performed on a 64-mT portable MRI system. A phantom validation experiment was performed, and a total of 33 in vivo exams were acquired from 28 neonates with postmenstrual age ranging from 31+4 to 49+0 weeks. Multiple inversion-recovery turbo spin-echo sequences were acquired with differing inversion and repetition times. An analysis pipeline incorporating inter-sequence motion correction generated proton density and T1 maps. Regions of interest were placed in the cerebral deep gray matter, frontal white matter, and cerebellum. Weighted linear regression was used to predict T1 as a function of postmenstrual age. RESULTS Reduction of T1 with postmenstrual age is observed in all measured brain tissue; the change in T1 per week and 95% confidence intervals is given by dT1 = -21 ms/week [-25, -16] (cerebellum), dT1 = -14 ms/week [-18, -10] (deep gray matter), and dT1 = -35 ms/week [-45, -25] (white matter). CONCLUSION Neonatal T1 values at ULF are shorter than those previously described at standard clinical field strengths, but longer than those of adults at ULF. T1 reduces with postmenstrual age and is therefore a candidate biomarker for perinatal brain development.
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Affiliation(s)
- Francesco Padormo
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
- Medical PhysicsGuy′s & St. Thomas' NHS Foundation TrustLondonUnited Kingdom
- Hyperfine, Inc.GuilfordConnecticutUSA
| | - Paul Cawley
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
- Medical Research Council Center for Neurodevelopmental DisordersKing′s College LondonLondonUnited Kingdom
- Department of NeonatologyGuy′s and St. Thomas′ NHS Foundation TrustLondonUnited Kingdom
| | - Louise Dillon
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
| | - Emer Hughes
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
| | - Jennifer Almalbis
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
- Department of NeonatologyGuy′s and St. Thomas′ NHS Foundation TrustLondonUnited Kingdom
| | - Joanna Robinson
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
- Department of NeonatologyGuy′s and St. Thomas′ NHS Foundation TrustLondonUnited Kingdom
| | - Alessandra Maggioni
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
- Department of NeonatologyGuy′s and St. Thomas′ NHS Foundation TrustLondonUnited Kingdom
| | - Miguel De La Fuente Botella
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
- Department of NeonatologyGuy′s and St. Thomas′ NHS Foundation TrustLondonUnited Kingdom
| | - Dan Cromb
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
- Department of NeonatologyGuy′s and St. Thomas′ NHS Foundation TrustLondonUnited Kingdom
| | - Anthony Price
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
- Medical PhysicsGuy′s & St. Thomas' NHS Foundation TrustLondonUnited Kingdom
| | | | | | | | | | - Sean C. L. Deoni
- Advanced Baby Imaging Lab, Rhode Island HospitalWarren, Alpert Medical School at Brown UniversityProvidenceRhode IslandUSA
- Department of Diagnostic RadiologyWarren Alpert Medical School at Brown UniversityProvidenceRhode IslandUSA
- Department of PediatricsWarren Alpert Medical School at Brown UniversityProvidenceRhode IslandUSA
| | - Steve Williams
- Medical Research Council Center for Neurodevelopmental DisordersKing′s College LondonLondonUnited Kingdom
- Center for Neuroimaging SciencesKing′s College LondonLondonUnited Kingdom
| | - Shaihan Malik
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
| | - Jonathan O′Muircheartaigh
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
- Medical Research Council Center for Neurodevelopmental DisordersKing′s College LondonLondonUnited Kingdom
- Department of Forensic and Neurodevelopmental Science, Institute of Psychiatry, Psychology and NeuroscienceKing′s College LondonLondonUnited Kingdom
| | - Serena J. Counsell
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
| | - Mary Rutherford
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
- Medical Research Council Center for Neurodevelopmental DisordersKing′s College LondonLondonUnited Kingdom
| | - Tomoki Arichi
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
- Medical Research Council Center for Neurodevelopmental DisordersKing′s College LondonLondonUnited Kingdom
- Department of BioengineeringImperial College LondonLondonUnited Kingdom
- Pediatric Neurosciences, Evelina London Children′s HospitalGuys′ and St. Thomas′ NHS Foundation TrustLondonUnited Kingdom
| | - A. David Edwards
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
- Medical Research Council Center for Neurodevelopmental DisordersKing′s College LondonLondonUnited Kingdom
- Department of NeonatologyGuy′s and St. Thomas′ NHS Foundation TrustLondonUnited Kingdom
| | - Joseph V. Hajnal
- Center for the Developing Brain, School of Imaging Sciences and Biomedical EngineeringKing′s College London
LondonUnited Kingdom
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7
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Clément J, Tomi-Tricot R, Malik SJ, Webb A, Hajnal JV, Ipek Ö. Towards an integrated neonatal brain and cardiac examination capability at 7 T: electromagnetic field simulations and early phantom experiments using an 8-channel dipole array. MAGMA (NEW YORK, N.Y.) 2022; 35:765-778. [PMID: 34997396 PMCID: PMC9463228 DOI: 10.1007/s10334-021-00988-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 12/06/2021] [Accepted: 12/06/2021] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Neonatal brain and cardiac imaging would benefit from the increased signal-to-noise ratio levels at 7 T compared to lower field. Optimal performance might be achieved using purpose designed RF coil arrays. In this study, we introduce an 8-channel dipole array and investigate, using simulations, its RF performances for neonatal applications at 7 T. METHODS The 8-channel dipole array was designed and evaluated for neonatal brain/cardiac configurations in terms of SAR efficiency (ratio between transmit-field and maximum specific-absorption-rate level) using adjusted dielectric properties for neonate. A birdcage coil operating in circularly polarized mode was simulated for comparison. Validation of the simulation model was performed on phantom for the coil array. RESULTS The 8-channel dipole array demonstrated up to 46% higher SAR efficiency levels compared to the birdcage coil in neonatal configurations, as the specific-absorption-rate levels were alleviated. An averaged normalized root-mean-square-error of 6.7% was found between measured and simulated transmit field maps on phantom. CONCLUSION The 8-channel dipole array design integrated for neonatal brain and cardiac MR was successfully demonstrated, in simulation with coverage of the baby and increased SAR efficiency levels compared to the birdcage. We conclude that the 8Tx-dipole array promises safe operating procedures for MR imaging of neonatal brain and heart at 7 T.
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Affiliation(s)
- Jérémie Clément
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | | | - Shaihan J Malik
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.,Centre for the Developing Brain, King's College London, London, UK
| | - Andrew Webb
- Department of Radiology, C. J Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands
| | - Joseph V Hajnal
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.,Centre for the Developing Brain, King's College London, London, UK
| | - Özlem Ipek
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.
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8
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Malik SJ, Hand JW, Carmichael DW, Hajnal JV. Evaluation of specific absorption rate and heating in children exposed to a 7T MRI head coil. Magn Reson Med 2022; 88:1434-1449. [PMID: 35666836 PMCID: PMC9328145 DOI: 10.1002/mrm.29283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 03/25/2022] [Accepted: 04/13/2022] [Indexed: 11/27/2022]
Abstract
PURPOSE To evaluate specific absorption rate (SAR) and temperature distributions resulting from pediatric exposure to a 7T head coil. METHODS Exposure from a 297-MHz birdcage head transmit coil (CP mode single-channel transmission) was simulated in several child models (ages 3-14, mass 13.9-50.4 kg) and one adult, using time-domain electromagnetic and thermal solvers. Position variability, age-related changes in dielectric properties, and differences in thermoregulation were also considered. RESULTS Age-adjusted dielectric properties had little effect in this population. Head average SAR (hdSAR) was the limiting factor for all models centered in the coil. The value of hdSAR (normalized to net power) was found to decrease linearly with increasing mass (R2 = 0.86); no equivalent relationship for peak-spatial 10g averaged SAR (psSAR10g ) was identified. Relatively small (< 10%) variability was observed in hdSAR for position shifts of ±25 mm in each orthogonal direction when normalized to net power; accounting for B1+$$ {\mathrm{B}}_1^{+} $$ efficiency can lead to much larger variability. Position sensitivity of psSAR10g was greater, but in most cases hdSAR remained the limiting quantity. For thermal simulations, if blood temperature is fixed (i.e., asserting good thermoregulation), maximum temperatures are compliant with International Electrotechnical Commission limits during 60-min exposure at the SAR limit. Introducing variable blood temperature leads to core temperature changes proportional to whole-body averaged SAR, exceeding guideline limits for all child models. CONCLUSIONS Children experienced higher SAR than adults for the 297-MHz head transmit coil examined in this work. Thermal simulations suggest that core temperature changes could occur in smaller subjects, although experimental data are needed for validation.
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Affiliation(s)
- Shaihan J Malik
- Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, UK.,Center for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, UK
| | - Jeffrey W Hand
- Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, UK
| | - David W Carmichael
- Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, UK
| | - Joseph V Hajnal
- Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, UK.,Center for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, UK
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9
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Cebeci B, Alderliesten T, Wijnen JP, van der Aa NE, Benders MJNL, de Vries LS, van den Hoogen A, Groenendaal F. Brain proton magnetic resonance spectroscopy and neurodevelopment after preterm birth: a systematic review. Pediatr Res 2022; 91:1322-1333. [PMID: 33953356 DOI: 10.1038/s41390-021-01539-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 03/31/2021] [Accepted: 04/05/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND Preterm infants are at risk of neurodevelopmental impairments. At present, proton magnetic resonance spectroscopy (1H-MRS) is used to evaluate brain metabolites in asphyxiated term infants. The aim of this review is to assess associations between cerebral 1H-MRS and neurodevelopment after preterm birth. METHODS PubMed and Embase were searched to identify studies using 1H-MRS and preterm birth. Eligible studies for this review included 1H-MRS of the brain, gestational age ≤32 weeks, and neurodevelopment assessed at a corrected age (CA) of at least 12 months up to the age of 18 years. RESULTS Twenty papers evaluated 1H-MRS in preterm infants at an age between near-term and 18 years and neurodevelopment. 1H-MRS was performed in both white (WM) and gray matter (GM) in 12 of 20 studies. The main regions were frontal and parietal lobe for WM and basal ganglia for GM. N-acetylaspartate/choline (NAA/Cho) measured in WM and/or GM is the most common metabolite ratio associated with motor, language, and cognitive outcome at 18-24 months CA. CONCLUSIONS NAA/Cho in WM assessed at term-equivalent age was associated with motor, cognitive, and language outcome, and NAA/Cho in deep GM was associated with language outcome at 18-24 months CA. IMPACT In preterm born infants, brain metabolism assessed using 1H-MRS at term-equivalent age is associated with motor, cognitive, and language outcomes at 18-24 months. 1H-MRS at term-equivalent age in preterm born infants may be used as an early indication of brain development. Specific findings relating to NAA were most predictive of outcome.
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Affiliation(s)
- Burcu Cebeci
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands.,Department of Neonatology, Health Sciences University, Haseki Training and Research Hospital, Istanbul, Turkey
| | - Thomas Alderliesten
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - Jannie P Wijnen
- Department of Radiology, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - Niek E van der Aa
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - Manon J N L Benders
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - Linda S de Vries
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - Agnes van den Hoogen
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - Floris Groenendaal
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands.
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10
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Korom M, Camacho MC, Filippi CA, Licandro R, Moore LA, Dufford A, Zöllei L, Graham AM, Spann M, Howell B, Shultz S, Scheinost D. Dear reviewers: Responses to common reviewer critiques about infant neuroimaging studies. Dev Cogn Neurosci 2021; 53:101055. [PMID: 34974250 PMCID: PMC8733260 DOI: 10.1016/j.dcn.2021.101055] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 11/28/2021] [Accepted: 12/26/2021] [Indexed: 01/07/2023] Open
Abstract
The field of adult neuroimaging relies on well-established principles in research design, imaging sequences, processing pipelines, as well as safety and data collection protocols. The field of infant magnetic resonance imaging, by comparison, is a young field with tremendous scientific potential but continuously evolving standards. The present article aims to initiate a constructive dialog between researchers who grapple with the challenges and inherent limitations of a nascent field and reviewers who evaluate their work. We address 20 questions that researchers commonly receive from research ethics boards, grant, and manuscript reviewers related to infant neuroimaging data collection, safety protocols, study planning, imaging sequences, decisions related to software and hardware, and data processing and sharing, while acknowledging both the accomplishments of the field and areas of much needed future advancements. This article reflects the cumulative knowledge of experts in the FIT’NG community and can act as a resource for both researchers and reviewers alike seeking a deeper understanding of the standards and tradeoffs involved in infant neuroimaging. The field of infant MRI is young with evolving standards. We address 20 questions that researchers commonly receive reviewers. These come from research ethics boards, grant, and manuscript reviewers. This article reflects the cumulative knowledge of experts in the FIT’NG community.
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Affiliation(s)
- Marta Korom
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE, USA.
| | - M Catalina Camacho
- Division of Biology and Biomedical Sciences (Neurosciences), Washington University School of Medicine, St. Louis, MO, USA.
| | - Courtney A Filippi
- Emotion and Development Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - Roxane Licandro
- Institute of Visual Computing and Human-Centered Technology, Computer Vision Lab, TU Wien, Vienna, Austria; Department of Biomedical Imaging and Image-guided Therapy, Computational Imaging Research, Medical University of Vienna, Vienna, Austria
| | - Lucille A Moore
- Department of Psychiatry, Oregon Health and Science University, Portland, OR, USA
| | - Alexander Dufford
- Department of Radiology & Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Lilla Zöllei
- A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA
| | - Alice M Graham
- Department of Psychiatry, Oregon Health and Science University, Portland, OR, USA
| | - Marisa Spann
- Department of Psychiatry, Columbia University Irving Medical Center, New York, NY, USA
| | - Brittany Howell
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Department of Human Development and Family Science, Virginia Polytechnic Institute and State University, Roanoke, VA, USA
| | | | - Sarah Shultz
- Division of Autism & Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA; Marcus Autism Center, Children's Healthcare of Atlanta, Atlanta, GA, USA.
| | - Dustin Scheinost
- Department of Radiology & Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA.
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11
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Malik SJ, Hand JW, Satnarine R, Price AN, Hajnal JV. Specific absorption rate and temperature in neonate models resulting from exposure to a 7T head coil. Magn Reson Med 2021; 86:1299-1313. [PMID: 33811667 DOI: 10.1002/mrm.28784] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 02/11/2021] [Accepted: 03/06/2021] [Indexed: 11/07/2022]
Abstract
PURPOSE To investigate safe limits for neonatal imaging using a 7T head coil, including both specific absorption rate (SAR) and temperature predictions. METHODS Head-centered neonate models were simulated using finite-difference time domain-based electromagnetic and thermal solvers. The effects of higher water content of neonatal tissues compared with adults, position shifts, and thermal insulation were also considered. An adult model was simulated for comparison. RESULTS Maximum and average SAR are both elevated in the neonate when compared with an adult model. When normalized to B1+ , the SAR experienced by a neonate is greater than an adult by approximately a factor of 2; when normalized to net forward power (forward-reflected), this increases to a factor of 2.5-3.0; and when normalized to absorbed power, approximately a factor of 4. Use of age-adjusted dielectric properties significantly increases the predicted SAR, compared with using adult tissue properties for the neonates. Thermal simulations predict that change in core temperature/maximum temperature remain compliant with International Electrotechnical Commission limits when a thermally insulated neonate is exposed at the SAR limit for up to an hour. CONCLUSION This study of two neonate models cannot quantify the variability expected within a larger population. Likewise, the use of age-adjusted dielectric properties have a significant effect, but while their use is well motivated by literature, there is uncertainty in the true dielectric properties of neonatal tissue. Nevertheless, the main finding is that unlike at lower field strengths, operational limits for 7T neonatal MRI using an adult head coil should be more conservative than limits for use on adults.
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Affiliation(s)
- Shaihan J Malik
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom.,Center for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
| | - Jeffrey W Hand
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
| | - Ryan Satnarine
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
| | - Anthony N Price
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom.,Center for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
| | - Joseph V Hajnal
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom.,Center for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
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12
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Sui Y, Afacan O, Gholipour A, Warfield SK. Fast and High-Resolution Neonatal Brain MRI Through Super-Resolution Reconstruction From Acquisitions With Variable Slice Selection Direction. Front Neurosci 2021; 15:636268. [PMID: 34220414 PMCID: PMC8242183 DOI: 10.3389/fnins.2021.636268] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 05/19/2021] [Indexed: 12/18/2022] Open
Abstract
The brain of neonates is small in comparison to adults. Imaging at typical resolutions such as one cubic mm incurs more partial voluming artifacts in a neonate than in an adult. The interpretation and analysis of MRI of the neonatal brain benefit from a reduction in partial volume averaging that can be achieved with high spatial resolution. Unfortunately, direct acquisition of high spatial resolution MRI is slow, which increases the potential for motion artifact, and suffers from reduced signal-to-noise ratio. The purpose of this study is thus that using super-resolution reconstruction in conjunction with fast imaging protocols to construct neonatal brain MRI images at a suitable signal-to-noise ratio and with higher spatial resolution than can be practically obtained by direct Fourier encoding. We achieved high quality brain MRI at a spatial resolution of isotropic 0.4 mm with 6 min of imaging time, using super-resolution reconstruction from three short duration scans with variable directions of slice selection. Motion compensation was achieved by aligning the three short duration scans together. We applied this technique to 20 newborns and assessed the quality of the images we reconstructed. Experiments show that our approach to super-resolution reconstruction achieved considerable improvement in spatial resolution and signal-to-noise ratio, while, in parallel, substantially reduced scan times, as compared to direct high-resolution acquisitions. The experimental results demonstrate that our approach allowed for fast and high-quality neonatal brain MRI for both scientific research and clinical studies.
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Affiliation(s)
- Yao Sui
- Computational Radiology Laboratory, Department of Radiology, Boston Children's Hospital, Boston, MA, United States
- Harvard Medical School, Boston, MA, United States
| | - Onur Afacan
- Computational Radiology Laboratory, Department of Radiology, Boston Children's Hospital, Boston, MA, United States
- Harvard Medical School, Boston, MA, United States
| | - Ali Gholipour
- Computational Radiology Laboratory, Department of Radiology, Boston Children's Hospital, Boston, MA, United States
- Harvard Medical School, Boston, MA, United States
| | - Simon K. Warfield
- Computational Radiology Laboratory, Department of Radiology, Boston Children's Hospital, Boston, MA, United States
- Harvard Medical School, Boston, MA, United States
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13
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Abstract
Magnetic resonance spectroscopy (MRS), being able to identify and measure some brain components (metabolites) in pathologic lesions and in normal-appearing tissue, offers a valuable additional diagnostic tool to assess several pediatric neurological diseases. In this review we will illustrate the basic principles and clinical applications of brain proton (H1; hydrogen) MRS (H1MRS), by now the only MRS method widely available in clinical practice. Performing H1MRS in the brain is inherently less complicated than in other tissues (e.g., liver, muscle), in which spectra are heavily affected by magnetic field inhomogeneities, respiration artifacts, and dominating signals from the surrounding adipose tissues. H1MRS in pediatric neuroradiology has some advantages over acquisitions in adults (lack of motion due to children sedation and lack of brain iron deposition allow optimal results), but it requires a deep knowledge of pediatric pathologies and familiarity with the developmental changes in spectral patterns, particularly occurring in the first two years of life. Examples from our database, obtained mainly from a 1.5 Tesla clinical scanner in a time span of 15 years, will demonstrate the efficacy of H1MRS in the diagnosis of a wide range of selected pediatric pathologies, like brain tumors, infections, neonatal hypoxic-ischemic encephalopathy, metabolic and white matter disorders.
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Affiliation(s)
- Roberto Liserre
- Department of Radiology, Neuroradiology Unit, ASST Spedali Civili University Hospital, Brescia, Italy
| | - Lorenzo Pinelli
- Department of Radiology, Neuroradiology Unit, ASST Spedali Civili University Hospital, Brescia, Italy
| | - Roberto Gasparotti
- Neuroradiology Unit, Department of Medical-Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
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