A simulation study on the effect of optimized high permittivity materials on fetal imaging at 3T.
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| Title: | A simulation study on the effect of optimized high permittivity materials on fetal imaging at 3T. |
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| Authors: | Gemert, Jeroen1 (AUTHOR), Brink, Wyger2 (AUTHOR), Remis, Rob1 (AUTHOR), Webb, Andrew2 (AUTHOR) a.webb@lumc.nl |
| Source: | Magnetic Resonance in Medicine. Nov2019, Vol. 82 Issue 5, p1822-1831. 10p. |
| Subjects: | Fetal imaging, Permittivity, Fetal MRI, Amniotic liquid, Structure-activity relationships |
| Abstract: | Purpose: One of the main concerns in fetal MRI is the radiofrequency power that is absorbed both by the mother and the fetus. Passive shimming using high permittivity materials in the form of "dielectric pads" has previously been shown to increase the B1+ efficiency and homogeneity in different applications, while reducing the specific absorption rate (SAR). In this work, we study the effect of optimized dielectric pads for 3 pregnant models. Methods: Pregnant models in the 3rd, 7th, and 9th months of gestation were used for simulations in a birdcage coil at 3T. Dielectric pads were optimized regions of interest (ROI) using previously developed methods for B1+ efficiency and homogeneity and were designed for 2 ROIs: the entire fetus and the brain of the fetus. The SAR was evaluated in terms of the whole‐body SAR, average SAR in the fetus and amniotic fluid, and maximum 10 g‐averaged SAR in the mother, fetus, and amniotic fluid. Results: The optimized dielectric pads increased the transmit efficiency up to 55% and increased the B1+ homogeneity in almost every tested configuration. The B1+‐normalized whole‐body SAR was reduced by more than 31% for all body models. The B1+‐normalized local SAR was reduced in most scenarios by up to 62%. Conclusion: Simulations have shown that optimized high permittivity pads can reduce SAR in pregnant subjects at the 3rd, 7th, and 9th month of gestation, while improving the transmit field homogeneity in the fetus. However, significantly more work is required to demonstrate that fetal imaging is safe under standard operating conditions. [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: 137720858 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: A simulation study on the effect of optimized high permittivity materials on fetal imaging at 3T. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Gemert%2C+Jeroen%22">Gemert, Jeroen</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Brink%2C+Wyger%22">Brink, Wyger</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Remis%2C+Rob%22">Remis, Rob</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Webb%2C+Andrew%22">Webb, Andrew</searchLink><relatesTo>2</relatesTo> (AUTHOR)<i> a.webb@lumc.nl</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Magnetic+Resonance+in+Medicine%22">Magnetic Resonance in Medicine</searchLink>. Nov2019, Vol. 82 Issue 5, p1822-1831. 10p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Fetal+imaging%22">Fetal imaging</searchLink><br /><searchLink fieldCode="DE" term="%22Permittivity%22">Permittivity</searchLink><br /><searchLink fieldCode="DE" term="%22Fetal+MRI%22">Fetal MRI</searchLink><br /><searchLink fieldCode="DE" term="%22Amniotic+liquid%22">Amniotic liquid</searchLink><br /><searchLink fieldCode="DE" term="%22Structure-activity+relationships%22">Structure-activity relationships</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Purpose: One of the main concerns in fetal MRI is the radiofrequency power that is absorbed both by the mother and the fetus. Passive shimming using high permittivity materials in the form of "dielectric pads" has previously been shown to increase the B1+ efficiency and homogeneity in different applications, while reducing the specific absorption rate (SAR). In this work, we study the effect of optimized dielectric pads for 3 pregnant models. Methods: Pregnant models in the 3rd, 7th, and 9th months of gestation were used for simulations in a birdcage coil at 3T. Dielectric pads were optimized regions of interest (ROI) using previously developed methods for B1+ efficiency and homogeneity and were designed for 2 ROIs: the entire fetus and the brain of the fetus. The SAR was evaluated in terms of the whole‐body SAR, average SAR in the fetus and amniotic fluid, and maximum 10 g‐averaged SAR in the mother, fetus, and amniotic fluid. Results: The optimized dielectric pads increased the transmit efficiency up to 55% and increased the B1+ homogeneity in almost every tested configuration. The B1+‐normalized whole‐body SAR was reduced by more than 31% for all body models. The B1+‐normalized local SAR was reduced in most scenarios by up to 62%. Conclusion: Simulations have shown that optimized high permittivity pads can reduce SAR in pregnant subjects at the 3rd, 7th, and 9th month of gestation, while improving the transmit field homogeneity in the fetus. However, significantly more work is required to demonstrate that fetal imaging is safe under standard operating conditions. [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.27849 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 10 StartPage: 1822 Subjects: – SubjectFull: Fetal imaging Type: general – SubjectFull: Permittivity Type: general – SubjectFull: Fetal MRI Type: general – SubjectFull: Amniotic liquid Type: general – SubjectFull: Structure-activity relationships Type: general Titles: – TitleFull: A simulation study on the effect of optimized high permittivity materials on fetal imaging at 3T. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Gemert, Jeroen – PersonEntity: Name: NameFull: Brink, Wyger – PersonEntity: Name: NameFull: Remis, Rob – PersonEntity: Name: NameFull: Webb, Andrew IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 11 Text: Nov2019 Type: published Y: 2019 Identifiers: – Type: issn-print Value: 07403194 Numbering: – Type: volume Value: 82 – Type: issue Value: 5 Titles: – TitleFull: Magnetic Resonance in Medicine Type: main |
| ResultId | 1 |
