Dependence of brain‐tissue R2 on MRI field strength.
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| Title: | Dependence of brain‐tissue R |
|---|---|
| Authors: | van Gelderen, Peter1 (AUTHOR) gelderen@nih.gov, Wang, Yicun1 (AUTHOR), de Zwart, Jacco A.1 (AUTHOR), Duyn, Jeff H.1 (AUTHOR) |
| Source: | Magnetic Resonance in Medicine. May2025, Vol. 93 Issue 5, p2140-2152. 13p. |
| Subjects: | Inductive effect, Radio frequency, Iron, Lipids, Magnetic resonance imaging |
| Abstract: | Purpose: To quantify T2 relaxation in the brain at 3 T and 7 T to study its field dependence and correlation with iron content, and to investigate whether iron can be separated from other sources of T2 relaxation based on this field dependence. Methods: Nine subjects were scanned at both field strengths with the same acquisition technique, which used multiple gradient‐echo sampling of a spin echo. This allowed for separation of T2 relaxation from static dephasing by B0 field inhomogeneities and the effects of radiofrequency refocusing imperfections. The average relaxation rates (R2 = 1/T2) in multiple regions of interest in the brain were fitted with a model linear in B0 and correlated with literature iron values. Results: The relationship between the R2 values at the two field strengths appeared to be linear over all regions of interest. The R2 values (in s−1) in the regions of interest for which both an iron and a lipid mass fraction have been documented in the literature were fitted as R2=9+0.9+2·104[Fe]+5.7[lipid]·B0$$ {\mathrm{R}}_2=9+\left(0.9+2\cdotp {10}^4\left[\mathrm{Fe}\right]+5.7\left[\mathrm{lipid}\right]\right)\cdotp {\mathrm{B}}_0 $$, where [Fe]$$ \left[\mathrm{Fe}\right] $$ and [lipid]$$ \left[\mathrm{lipid}\right] $$ indicate the putative mass fractions of iron and lipid. Conclusion: The R2 relaxation rate is well described by a constant plus a term linear in B0, with both iron and lipid content contributing to the slope. This indicates that the contributions of lipid and iron to R2 cannot be separated based solely on the field dependence of R2 in the field range of 3–7 T. [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.) | |
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| Items | – Name: Title Label: Title Group: Ti Data: Dependence of brain‐tissue R<subscript>2</subscript> on MRI field strength. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22van+Gelderen%2C+Peter%22">van Gelderen, Peter</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> gelderen@nih.gov</i><br /><searchLink fieldCode="AR" term="%22Wang%2C+Yicun%22">Wang, Yicun</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22de+Zwart%2C+Jacco+A%2E%22">de Zwart, Jacco A.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Duyn%2C+Jeff+H%2E%22">Duyn, Jeff H.</searchLink><relatesTo>1</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Magnetic+Resonance+in+Medicine%22">Magnetic Resonance in Medicine</searchLink>. May2025, Vol. 93 Issue 5, p2140-2152. 13p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Inductive+effect%22">Inductive effect</searchLink><br /><searchLink fieldCode="DE" term="%22Radio+frequency%22">Radio frequency</searchLink><br /><searchLink fieldCode="DE" term="%22Iron%22">Iron</searchLink><br /><searchLink fieldCode="DE" term="%22Lipids%22">Lipids</searchLink><br /><searchLink fieldCode="DE" term="%22Magnetic+resonance+imaging%22">Magnetic resonance imaging</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Purpose: To quantify T2 relaxation in the brain at 3 T and 7 T to study its field dependence and correlation with iron content, and to investigate whether iron can be separated from other sources of T2 relaxation based on this field dependence. Methods: Nine subjects were scanned at both field strengths with the same acquisition technique, which used multiple gradient‐echo sampling of a spin echo. This allowed for separation of T2 relaxation from static dephasing by B0 field inhomogeneities and the effects of radiofrequency refocusing imperfections. The average relaxation rates (R2 = 1/T2) in multiple regions of interest in the brain were fitted with a model linear in B0 and correlated with literature iron values. Results: The relationship between the R2 values at the two field strengths appeared to be linear over all regions of interest. The R2 values (in s−1) in the regions of interest for which both an iron and a lipid mass fraction have been documented in the literature were fitted as R2=9+0.9+2·104[Fe]+5.7[lipid]·B0$$ {\mathrm{R}}_2=9+\left(0.9+2\cdotp {10}^4\left[\mathrm{Fe}\right]+5.7\left[\mathrm{lipid}\right]\right)\cdotp {\mathrm{B}}_0 $$, where [Fe]$$ \left[\mathrm{Fe}\right] $$ and [lipid]$$ \left[\mathrm{lipid}\right] $$ indicate the putative mass fractions of iron and lipid. Conclusion: The R2 relaxation rate is well described by a constant plus a term linear in B0, with both iron and lipid content contributing to the slope. This indicates that the contributions of lipid and iron to R2 cannot be separated based solely on the field dependence of R2 in the field range of 3–7 T. [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.30400 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 13 StartPage: 2140 Subjects: – SubjectFull: Inductive effect Type: general – SubjectFull: Radio frequency Type: general – SubjectFull: Iron Type: general – SubjectFull: Lipids Type: general – SubjectFull: Magnetic resonance imaging Type: general Titles: – TitleFull: Dependence of brain‐tissue R2 on MRI field strength. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: van Gelderen, Peter – PersonEntity: Name: NameFull: Wang, Yicun – PersonEntity: Name: NameFull: de Zwart, Jacco A. – PersonEntity: Name: NameFull: Duyn, Jeff H. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 05 Text: May2025 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 07403194 Numbering: – Type: volume Value: 93 – Type: issue Value: 5 Titles: – TitleFull: Magnetic Resonance in Medicine Type: main |
| ResultId | 1 |
