Global optimization of default phases for parallel transmit coils for ultra-high-field cardiac MRI
Please always quote using this URN: urn:nbn:de:bvb:20-opus-265737
- The development of novel multiple-element transmit-receive arrays is an essential factor for improving B\(_1\)\(^+\) field homogeneity in cardiac MRI at ultra-high magnetic field strength (B\(_0\) > = 7.0T). One of the key steps in the design and fine-tuning of such arrays during the development process is finding the default driving phases for individual coil elements providing the best possible homogeneity of the combined B\(_1\)\(^+\)-field that is achievable without (or before) subject-specific B\(_1\)\(^+\)-adjustment in the scanner. ThisThe development of novel multiple-element transmit-receive arrays is an essential factor for improving B\(_1\)\(^+\) field homogeneity in cardiac MRI at ultra-high magnetic field strength (B\(_0\) > = 7.0T). One of the key steps in the design and fine-tuning of such arrays during the development process is finding the default driving phases for individual coil elements providing the best possible homogeneity of the combined B\(_1\)\(^+\)-field that is achievable without (or before) subject-specific B\(_1\)\(^+\)-adjustment in the scanner. This task is often solved by time-consuming (brute-force) or by limited efficiency optimization methods. In this work, we propose a robust technique to find phase vectors providing optimization of the B-1-homogeneity in the default setup of multiple-element transceiver arrays. The key point of the described method is the pre-selection of starting vectors for the iterative solver-based search to maximize the probability of finding a global extremum for a cost function optimizing the homogeneity of a shaped B\(_1\)\(^+\)-field. This strategy allows for (i) drastic reduction of the computation time in comparison to a brute-force method and (ii) finding phase vectors providing a combined B\(_1\)\(^+\)-field with homogeneity characteristics superior to the one provided by the random-multi-start optimization approach. The method was efficiently used for optimizing the default phase settings in the in-house-built 8Tx/16Rx arrays designed for cMRI in pigs at 7T.…
Author: | Maxim TerekhovORCiD, Ibrahim A. Elabyad, Laura M. Schreiber |
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URN: | urn:nbn:de:bvb:20-opus-265737 |
Document Type: | Journal article |
Faculties: | Medizinische Fakultät / Deutsches Zentrum für Herzinsuffizienz (DZHI) |
Language: | English |
Parent Title (English): | PLoS One |
Year of Completion: | 2021 |
Volume: | 16 |
Issue: | 8 |
Article Number: | e0255341 |
Source: | PLoS One (2021) 16:8, e0255341. https://doi.org/10.1371/journal.pone.0255341 |
DOI: | https://doi.org/10.1371/journal.pone.0255341 |
Dewey Decimal Classification: | 6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit |
Tag: | electromagnetics; linear regression analysis; magnetic resonance imaging; optimization; power grids; swine; thorax; wave interference |
Release Date: | 2022/05/02 |
Collections: | Open-Access-Publikationsfonds / Förderzeitraum 2021 |
Licence (German): | CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International |