Characterization of concomitant gradient fields and their effects on image distortions using a low‐field point‐of‐care Halbach‐based MRI system.
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| Title: | Characterization of concomitant gradient fields and their effects on image distortions using a low‐field point‐of‐care Halbach‐based MRI system. |
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| Authors: | de Vos, Bart1 (AUTHOR) b.de_vos@lumc.nl, Remis, Rob F.2 (AUTHOR), Webb, Andrew G.1,3 (AUTHOR) |
| Source: | Magnetic Resonance in Medicine. Feb2024, Vol. 91 Issue 2, p828-841. 14p. |
| Subjects: | Inductive effect, Image analysis, Point-of-care testing, Magnetic field effects, Phase coding |
| Abstract: | Purpose: Concomitant gradient fields have been extensively studied at clinical field strengths. However, their effects have not yet been modeled for low‐field point‐of‐care (POC) systems. The purpose of this work is to characterize the effects associated with concomitant fields for POC Halbach‐array‐based systems. Methods: The concomitant fields associated with a cylindrical gradient coils designed for a transverse B0$$ {B}_0 $$ and a signal model including the tilting effect of the effective magnetic field are derived. The formalism is used to simulate and predict concomitant field related distortions. A 46‐mT Halbach‐array‐based system with a maximum gradient strength of 15 mT/m is used to verify the model using two‐dimensional spin‐echo sequences. Results: The simulations and experimental results are in good agreement with the derived equations. The fundamental characteristics of the concomitant field equations are different to conventional MRI systems: Image distortions occur primarily in the transverse directions and a cross‐term only exists when applying transverse gradient pulses simultaneously. Conclusion: The level of image warping in the frequency encoding direction is insignificant for the POC systems discussed here. However, when trying to achieve short echo‐times by using strong phase encoding and readout‐dephasing gradients, the combination can result in image warping and blurring which should be accounted for in image interpretation. [ABSTRACT FROM AUTHOR] |
| Copyright of Magnetic Resonance in Medicine is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
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| Header | DbId: egs DbLabel: Engineering Source An: 173925245 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Characterization of concomitant gradient fields and their effects on image distortions using a low‐field point‐of‐care Halbach‐based MRI system. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22de+Vos%2C+Bart%22">de Vos, Bart</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> b.de_vos@lumc.nl</i><br /><searchLink fieldCode="AR" term="%22Remis%2C+Rob+F%2E%22">Remis, Rob F.</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Webb%2C+Andrew+G%2E%22">Webb, Andrew G.</searchLink><relatesTo>1,3</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Magnetic+Resonance+in+Medicine%22">Magnetic Resonance in Medicine</searchLink>. Feb2024, Vol. 91 Issue 2, p828-841. 14p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Inductive+effect%22">Inductive effect</searchLink><br /><searchLink fieldCode="DE" term="%22Image+analysis%22">Image analysis</searchLink><br /><searchLink fieldCode="DE" term="%22Point-of-care+testing%22">Point-of-care testing</searchLink><br /><searchLink fieldCode="DE" term="%22Magnetic+field+effects%22">Magnetic field effects</searchLink><br /><searchLink fieldCode="DE" term="%22Phase+coding%22">Phase coding</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Purpose: Concomitant gradient fields have been extensively studied at clinical field strengths. However, their effects have not yet been modeled for low‐field point‐of‐care (POC) systems. The purpose of this work is to characterize the effects associated with concomitant fields for POC Halbach‐array‐based systems. Methods: The concomitant fields associated with a cylindrical gradient coils designed for a transverse B0$$ {B}_0 $$ and a signal model including the tilting effect of the effective magnetic field are derived. The formalism is used to simulate and predict concomitant field related distortions. A 46‐mT Halbach‐array‐based system with a maximum gradient strength of 15 mT/m is used to verify the model using two‐dimensional spin‐echo sequences. Results: The simulations and experimental results are in good agreement with the derived equations. The fundamental characteristics of the concomitant field equations are different to conventional MRI systems: Image distortions occur primarily in the transverse directions and a cross‐term only exists when applying transverse gradient pulses simultaneously. Conclusion: The level of image warping in the frequency encoding direction is insignificant for the POC systems discussed here. However, when trying to achieve short echo‐times by using strong phase encoding and readout‐dephasing gradients, the combination can result in image warping and blurring which should be accounted for in image interpretation. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Magnetic Resonance in Medicine is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1002/mrm.29879 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 14 StartPage: 828 Subjects: – SubjectFull: Inductive effect Type: general – SubjectFull: Image analysis Type: general – SubjectFull: Point-of-care testing Type: general – SubjectFull: Magnetic field effects Type: general – SubjectFull: Phase coding Type: general Titles: – TitleFull: Characterization of concomitant gradient fields and their effects on image distortions using a low‐field point‐of‐care Halbach‐based MRI system. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: de Vos, Bart – PersonEntity: Name: NameFull: Remis, Rob F. – PersonEntity: Name: NameFull: Webb, Andrew G. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 02 Text: Feb2024 Type: published Y: 2024 Identifiers: – Type: issn-print Value: 07403194 Numbering: – Type: volume Value: 91 – Type: issue Value: 2 Titles: – TitleFull: Magnetic Resonance in Medicine Type: main |
| ResultId | 1 |
