TY  - JOUR
AU  - Lutz, Max
AU  - Aigner, Christoph Stefan
AU  - Flassbeck, Sebastian
AU  - Krueger, Felix
AU  - Gatefait, Constance G F
AU  - Kolbitsch, Christoph
AU  - Silemek, Berk
AU  - Seifert, Frank
AU  - Schaeffter, Tobias
AU  - Schmitter, Sebastian
TI  - B1-MRF: Large dynamic range MRF-based absolute B 1 + mapping in the human body at 7T.
JO  - Magnetic resonance in medicine
VL  - 92
IS  - 6
SN  - 1522-2594
CY  - New York, NY [u.a.]
PB  - Wiley-Liss
M1  - DKFZ-2024-01652
SP  - 2473-2490
PY  - 2024
N1  - #LA:E020#/ 2024 Dec;92(6):2473-2490
AB  - This study aims to map the transmit magnetic field ( B 1 + 
AB  - <br clear="all" /><table border="0" width="100%"><tr><td>
AB  - <table align="center" cellspacing="0"  cellpadding="2"><tr><td nowrap="nowrap" align="center">
AB  -  B<sub>1</sub><sup>+</sup> </td></tr></table>
AB  - </td></tr></table>
AB  - 
AB  -  ) in the human body at 7T using MR fingerprinting (MRF), with a focus on achieving high accuracy and precision across a large dynamic range, particularly at low flip angles (FAs).A FLASH-based MRF sequence (B1-MRF) with high B 1 + 
AB  - <br clear="all" /><table border="0" width="100%"><tr><td>
AB  - <table align="center" cellspacing="0"  cellpadding="2"><tr><td nowrap="nowrap" align="center">
AB  -  B<sub>1</sub><sup>+</sup> </td></tr></table>
AB  - </td></tr></table>
AB  - 
AB  -  sensitivity was developed. Phantom and in vivo abdominal imaging were performed at 7T, and the results were compared with established reference methods, including a slow but precise preparation-based method (PEX), saturated TurboFLASH (satTFL), actual flip angle imaging (AFI) and Bloch-Siegert shift (BSS).The MRF signal curve was highly sensitive to B 1 + 
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AB  -  B<sub>1</sub><sup>+</sup> </td></tr></table>
AB  - </td></tr></table>
AB  - 
AB  -  , while T1 sensitivity was comparatively low. The phantom experiment showed good agreement of B 1 + 
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AB  - <table align="center" cellspacing="0"  cellpadding="2"><tr><td nowrap="nowrap" align="center">
AB  -  B<sub>1</sub><sup>+</sup> </td></tr></table>
AB  - </td></tr></table>
AB  - 
AB  -  to PEX for a T1 range of 204-1691 ms evaluated at FAs from 0° to 70°. Compared to the references, a dynamic range increase larger than a factor of two was determined experimentally. In vivo liver scans showed a strong correlation between B1-MRF, satTFL, and RPE-AFI in a low body mass index (BMI) subject (18.1 kg/m2). However, in larger BMI subjects (≥25.5 kg/m2), inconsistencies were observed in low B 1 + 
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AB  - <table align="center" cellspacing="0"  cellpadding="2"><tr><td nowrap="nowrap" align="center">
AB  -  B<sub>1</sub><sup>+</sup> </td></tr></table>
AB  - </td></tr></table>
AB  - 
AB  -  regions for satTFL and RPE-AFI, while B1-MRF still provided consistent results in these regions.B1-MRF provides accurate and precise B 1 + 
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AB  - <table align="center" cellspacing="0"  cellpadding="2"><tr><td nowrap="nowrap" align="center">
AB  -  B<sub>1</sub><sup>+</sup> </td></tr></table>
AB  - </td></tr></table>
AB  - 
AB  -  maps over a wide range of FAs, surpassing the capabilities of existing methods in the FA range < 60°. Its enhanced sensitivity at low FAs is advantageous for various applications requiring precise B 1 + 
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AB  - <table align="center" cellspacing="0"  cellpadding="2"><tr><td nowrap="nowrap" align="center">
AB  -  B<sub>1</sub><sup>+</sup> </td></tr></table>
AB  - </td></tr></table>
AB  - 
AB  -  estimates, potentially advancing the frontiers of ultra-high field (UHF) body imaging at 7T and beyond.
KW  -                                                                                                               B                            1                            +                                                                     $$ {B}_1^{+} $$                                    mapping (Other)
KW  - 7 Tesla (Other)
KW  - MRF (Other)
KW  - body MRI (Other)
KW  - ultrahigh field MRI (Other)
LB  - PUB:(DE-HGF)16
C6  - pmid:39133639
DO  - DOI:10.1002/mrm.30242
UR  - https://inrepo02.dkfz.de/record/292291
ER  -