Optimization of pseudo‐continuous arterial spin labeling using off‐resonance compensation strategies at 7T.
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| Title: | Optimization of pseudo‐continuous arterial spin labeling using off‐resonance compensation strategies at 7T. |
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| Authors: | Saïb, Gaël1 (AUTHOR) saibgh@nih.gov, Koretsky, Alan P.1 (AUTHOR), Talagala, S. Lalith2 (AUTHOR) |
| Source: | Magnetic Resonance in Medicine. Apr2022, Vol. 87 Issue 4, p1720-1730. 11p. |
| Subjects: | Spin labels, Radio frequency, Perfusion, Arteries |
| Abstract: | Purpose: The sensitivity of pseudo‐continuous arterial spin labeling (PCASL) to off‐resonance effects (ΔB0) is a major limitation at ultra‐high field (≥7T). The aim of this study was to assess the effectiveness of different PCASL ΔB0 compensation methods at 7T and measure the labeling efficiency with off‐resonance correction. Theory and Methods: Phase offset errors induced by ΔB0 at the feeding arteries can be compensated by adding an extra radiofrequency (RF) phase increment and transverse gradient blips into the PCASL RF pulse train. The effectiveness of an average field correction (AVGcor), a vessel‐specific field‐map‐based correction (FMcor) and a vessel‐specific prescan‐based correction (PScor) were compared at 7T. After correction, the PCASL labeling efficiency was directly measured in feeding arteries downstream from the labeling location. Results: The perfusion signal was more uniform throughout the brain after off‐resonance correction. Whole‐brain average perfusion signal increased by a factor of 2.4, 2.5, and 2.1, respectively, with AVGcor, FMcor and PScor compared to acquisitions without correction. With off‐resonance correction, the maximum labeling efficiency was ~0.68 at mean B1 (B1mean) of 0.70 µT when using a mean gradient (Gmean) of 0.25 mT/m. Conclusion: Either a prescan or a field map can be used to correct for off‐resonance effects and retrieve a good brain perfusion signal at 7T. Although the three methods performed well in this study, FMcor may be better suited for patient studies because it accounted for vessel‐specific ΔB0 variations. Further improvements in image quality will be possible by optimizing the labeling efficiency with advanced hardware and software while satisfying specific absorption rate constraints. [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: 154961848 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Optimization of pseudo‐continuous arterial spin labeling using off‐resonance compensation strategies at 7T. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Saïb%2C+Gaël%22">Saïb, Gaël</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> saibgh@nih.gov</i><br /><searchLink fieldCode="AR" term="%22Koretsky%2C+Alan+P%2E%22">Koretsky, Alan P.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Talagala%2C+S%2E+Lalith%22">Talagala, S. Lalith</searchLink><relatesTo>2</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Magnetic+Resonance+in+Medicine%22">Magnetic Resonance in Medicine</searchLink>. Apr2022, Vol. 87 Issue 4, p1720-1730. 11p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Spin+labels%22">Spin labels</searchLink><br /><searchLink fieldCode="DE" term="%22Radio+frequency%22">Radio frequency</searchLink><br /><searchLink fieldCode="DE" term="%22Perfusion%22">Perfusion</searchLink><br /><searchLink fieldCode="DE" term="%22Arteries%22">Arteries</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Purpose: The sensitivity of pseudo‐continuous arterial spin labeling (PCASL) to off‐resonance effects (ΔB0) is a major limitation at ultra‐high field (≥7T). The aim of this study was to assess the effectiveness of different PCASL ΔB0 compensation methods at 7T and measure the labeling efficiency with off‐resonance correction. Theory and Methods: Phase offset errors induced by ΔB0 at the feeding arteries can be compensated by adding an extra radiofrequency (RF) phase increment and transverse gradient blips into the PCASL RF pulse train. The effectiveness of an average field correction (AVGcor), a vessel‐specific field‐map‐based correction (FMcor) and a vessel‐specific prescan‐based correction (PScor) were compared at 7T. After correction, the PCASL labeling efficiency was directly measured in feeding arteries downstream from the labeling location. Results: The perfusion signal was more uniform throughout the brain after off‐resonance correction. Whole‐brain average perfusion signal increased by a factor of 2.4, 2.5, and 2.1, respectively, with AVGcor, FMcor and PScor compared to acquisitions without correction. With off‐resonance correction, the maximum labeling efficiency was ~0.68 at mean B1 (B1mean) of 0.70 µT when using a mean gradient (Gmean) of 0.25 mT/m. Conclusion: Either a prescan or a field map can be used to correct for off‐resonance effects and retrieve a good brain perfusion signal at 7T. Although the three methods performed well in this study, FMcor may be better suited for patient studies because it accounted for vessel‐specific ΔB0 variations. Further improvements in image quality will be possible by optimizing the labeling efficiency with advanced hardware and software while satisfying specific absorption rate constraints. [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.29070 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 11 StartPage: 1720 Subjects: – SubjectFull: Spin labels Type: general – SubjectFull: Radio frequency Type: general – SubjectFull: Perfusion Type: general – SubjectFull: Arteries Type: general Titles: – TitleFull: Optimization of pseudo‐continuous arterial spin labeling using off‐resonance compensation strategies at 7T. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Saïb, Gaël – PersonEntity: Name: NameFull: Koretsky, Alan P. – PersonEntity: Name: NameFull: Talagala, S. Lalith IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 04 Text: Apr2022 Type: published Y: 2022 Identifiers: – Type: issn-print Value: 07403194 Numbering: – Type: volume Value: 87 – Type: issue Value: 4 Titles: – TitleFull: Magnetic Resonance in Medicine Type: main |
| ResultId | 1 |
