Extended Monopole antenna Array with individual Shield (EMAS) coil: An improved monopole antenna design for brain imaging at 7 tesla MRI
Purpose To propose a new Extended Monopole antenna Array with individual Shields (EMAS) coil that improves the B1 field coverage and uniformity along the z‐direction. Methods To increase the spatial coverage of Monopole antenna Array (MA) coil, each monopole antenna was shielded and extended in leng...
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Published in | Magnetic resonance in medicine Vol. 75; no. 6; pp. 2566 - 2572 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Blackwell Publishing Ltd
01.06.2016
Wiley Subscription Services, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | Purpose
To propose a new Extended Monopole antenna Array with individual Shields (EMAS) coil that improves the B1 field coverage and uniformity along the z‐direction.
Methods
To increase the spatial coverage of Monopole antenna Array (MA) coil, each monopole antenna was shielded and extended in length. Performance of this new coil, which is referred to as EMAS coil, was compared with the original MA coil and an Extended Monopole antenna Array coil with no shield (EMA). For comparison, flip angle, signal‐to‐noise ratio (SNR), and receive sensitivity maps were measured at multiple regions of interest (ROIs) in the brain.
Results
The EMAS coil demonstrated substantially larger flip angle and receive sensitivity than the MA and EMA coils in the inferior aspect of the brain. In the brainstem ROI, for example, the flip angle in the EMAS coil was increased by 45.5% (or 60.0%) and the receive sensitivity was increased by 26.9% (or 14.9%), resulting in an SNR gain of 84.8% (or 76.3%) when compared with the MA coil (or EMA).
Conclusion
The EMAS coil provided 25.7% (or 24.4%) more uniform
B1+ field distribution compared with the MA (or EMA) coil in sagittal. The EMAS coil successfully extended the imaging volume in lower part of the brain. Magn Reson Med 75:2566–2572, 2016. © 2015 Wiley Periodicals, Inc. |
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Bibliography: | ArticleID:MRM25837 Ministry of Science, ICT, and Future Planning - No. 2006-2005137 istex:50CA3B86F5FBC98B97EC55D62B18C4985B90BB29 ark:/67375/WNG-V9QWSV98-H ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0740-3194 1522-2594 |
DOI: | 10.1002/mrm.25837 |