Abstract
Purpose: Highly accelerated B 1 +-mapping based on the Bloch–Siegert shift to allow 3D acquisitions even within a brief period of a single breath-hold. Theory and Methods: The B 1 + dependent Bloch–Siegert phase shift is measured within a highly subsampled 3D-volume and reconstructed using a two-step variational approach, exploiting the different spatial distribution of morphology and B 1 + -field. By appropriate variable substitution the basic non-convex optimization problem is transformed in a sequential solution of two convex optimization problems with a total generalized variation (TGV) regularization for the morphology part and a smoothness constraint for the B 1 + -field. The method is evaluated on 3D in vivo data with retro- and prospective subsampling. The reconstructed B 1 + -maps are compared to a zero-padded low resolution reconstruction and a fully sampled reference. Results: The reconstructed B 1 + -field maps are in high accordance to the reference for all measurements with a mean error below 1% and a maximum of about 4% for acceleration factors up to 100. The minimal error for different sampling patterns was achieved by sampling a dense region in k-space center with acquisition times of around 10–12 s for 3D-acquistions. Conclusions: The proposed variational approach enables highly accelerated 3D acquisitions of Bloch–Siegert data and thus full liver coverage in a single breath hold.
| Original language | English |
|---|---|
| Pages (from-to) | 881-892 |
| Number of pages | 12 |
| Journal | Magnetic Resonance in Medicine |
| Volume | 81 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 1 Feb 2019 |
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Ultrafast 3D Bloch–Siegert B+1‐mapping using variational modeling. / Lesch, Andreas Johann; Schlögl, Matthias; Holler, Martin; Bredies, Kristian; Stollberger, Rudolf.
In: Magnetic Resonance in Medicine, Vol. 81, No. 2, 01.02.2019, p. 881-892.Research output: Contribution to journal › Article › Research › peer-review
}
TY - JOUR
T1 - Ultrafast 3D Bloch–Siegert B+1‐mapping using variational modeling
AU - Lesch, Andreas Johann
AU - Schlögl, Matthias
AU - Holler, Martin
AU - Bredies, Kristian
AU - Stollberger, Rudolf
N1 - © 2018 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.
PY - 2019/2/1
Y1 - 2019/2/1
N2 - Purpose: Highly accelerated B 1 +-mapping based on the Bloch–Siegert shift to allow 3D acquisitions even within a brief period of a single breath-hold. Theory and Methods: The B 1 + dependent Bloch–Siegert phase shift is measured within a highly subsampled 3D-volume and reconstructed using a two-step variational approach, exploiting the different spatial distribution of morphology and B 1 + -field. By appropriate variable substitution the basic non-convex optimization problem is transformed in a sequential solution of two convex optimization problems with a total generalized variation (TGV) regularization for the morphology part and a smoothness constraint for the B 1 + -field. The method is evaluated on 3D in vivo data with retro- and prospective subsampling. The reconstructed B 1 + -maps are compared to a zero-padded low resolution reconstruction and a fully sampled reference. Results: The reconstructed B 1 + -field maps are in high accordance to the reference for all measurements with a mean error below 1% and a maximum of about 4% for acceleration factors up to 100. The minimal error for different sampling patterns was achieved by sampling a dense region in k-space center with acquisition times of around 10–12 s for 3D-acquistions. Conclusions: The proposed variational approach enables highly accelerated 3D acquisitions of Bloch–Siegert data and thus full liver coverage in a single breath hold.
AB - Purpose: Highly accelerated B 1 +-mapping based on the Bloch–Siegert shift to allow 3D acquisitions even within a brief period of a single breath-hold. Theory and Methods: The B 1 + dependent Bloch–Siegert phase shift is measured within a highly subsampled 3D-volume and reconstructed using a two-step variational approach, exploiting the different spatial distribution of morphology and B 1 + -field. By appropriate variable substitution the basic non-convex optimization problem is transformed in a sequential solution of two convex optimization problems with a total generalized variation (TGV) regularization for the morphology part and a smoothness constraint for the B 1 + -field. The method is evaluated on 3D in vivo data with retro- and prospective subsampling. The reconstructed B 1 + -maps are compared to a zero-padded low resolution reconstruction and a fully sampled reference. Results: The reconstructed B 1 + -field maps are in high accordance to the reference for all measurements with a mean error below 1% and a maximum of about 4% for acceleration factors up to 100. The minimal error for different sampling patterns was achieved by sampling a dense region in k-space center with acquisition times of around 10–12 s for 3D-acquistions. Conclusions: The proposed variational approach enables highly accelerated 3D acquisitions of Bloch–Siegert data and thus full liver coverage in a single breath hold.
UR - http://www.scopus.com/inward/record.url?scp=85054899343&partnerID=8YFLogxK
U2 - 10.1002/mrm.27434
DO - 10.1002/mrm.27434
M3 - Article
VL - 81
SP - 881
EP - 892
JO - Magnetic Resonance in Medicine
JF - Magnetic Resonance in Medicine
SN - 0740-3194
IS - 2
ER -