%0 Journal Article
%A Lutz, Max
%A Aigner, Christoph Stefan
%A Flassbeck, Sebastian
%A Krueger, Felix
%A Gatefait, Constance G F
%A Kolbitsch, Christoph
%A Silemek, Berk
%A Seifert, Frank
%A Schaeffter, Tobias
%A Schmitter, Sebastian
%T B1-MRF: Large dynamic range MRF-based absolute B 1 + mapping in the human body at 7T.
%J Magnetic resonance in medicine
%V 92
%N 6
%@ 1522-2594
%C New York, NY [u.a.]
%I Wiley-Liss
%M DKFZ-2024-01652
%P 2473-2490
%D 2024
%Z #LA:E020#/ 2024 Dec;92(6):2473-2490
%X This study aims to map the transmit magnetic field ( B 1 + 
%X <br clear="all" /><table border="0" width="100%"><tr><td>
%X <table align="center" cellspacing="0"  cellpadding="2"><tr><td nowrap="nowrap" align="center">
%X  B<sub>1</sub><sup>+</sup> </td></tr></table>
%X </td></tr></table>
%X 
%X  ) 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 + 
%X <br clear="all" /><table border="0" width="100%"><tr><td>
%X <table align="center" cellspacing="0"  cellpadding="2"><tr><td nowrap="nowrap" align="center">
%X  B<sub>1</sub><sup>+</sup> </td></tr></table>
%X </td></tr></table>
%X 
%X  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 + 
%X <br clear="all" /><table border="0" width="100%"><tr><td>
%X <table align="center" cellspacing="0"  cellpadding="2"><tr><td nowrap="nowrap" align="center">
%X  B<sub>1</sub><sup>+</sup> </td></tr></table>
%X </td></tr></table>
%X 
%X  , while T1 sensitivity was comparatively low. The phantom experiment showed good agreement of B 1 + 
%X <br clear="all" /><table border="0" width="100%"><tr><td>
%X <table align="center" cellspacing="0"  cellpadding="2"><tr><td nowrap="nowrap" align="center">
%X  B<sub>1</sub><sup>+</sup> </td></tr></table>
%X </td></tr></table>
%X 
%X  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 + 
%X <br clear="all" /><table border="0" width="100%"><tr><td>
%X <table align="center" cellspacing="0"  cellpadding="2"><tr><td nowrap="nowrap" align="center">
%X  B<sub>1</sub><sup>+</sup> </td></tr></table>
%X </td></tr></table>
%X 
%X  regions for satTFL and RPE-AFI, while B1-MRF still provided consistent results in these regions.B1-MRF provides accurate and precise B 1 + 
%X <br clear="all" /><table border="0" width="100%"><tr><td>
%X <table align="center" cellspacing="0"  cellpadding="2"><tr><td nowrap="nowrap" align="center">
%X  B<sub>1</sub><sup>+</sup> </td></tr></table>
%X </td></tr></table>
%X 
%X  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 + 
%X <br clear="all" /><table border="0" width="100%"><tr><td>
%X <table align="center" cellspacing="0"  cellpadding="2"><tr><td nowrap="nowrap" align="center">
%X  B<sub>1</sub><sup>+</sup> </td></tr></table>
%X </td></tr></table>
%X 
%X  estimates, potentially advancing the frontiers of ultra-high field (UHF) body imaging at 7T and beyond.
%K                                                                                                               B                            1                            +                                                                     $$ {B}_1^{+} $$                                    mapping (Other)
%K 7 Tesla (Other)
%K MRF (Other)
%K body MRI (Other)
%K ultrahigh field MRI (Other)
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:39133639
%R 10.1002/mrm.30242
%U https://inrepo02.dkfz.de/record/292291