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Global optimization of default phases for parallel transmit coils for ultra-high-field cardiac MRI
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- 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.…
Autor(en): | Maxim TerekhovORCiD, Ibrahim A. Elabyad, Laura M. Schreiber |
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URN: | urn:nbn:de:bvb:20-opus-265737 |
Dokumentart: | Artikel / Aufsatz in einer Zeitschrift |
Institute der Universität: | Medizinische Fakultät / Deutsches Zentrum für Herzinsuffizienz (DZHI) |
Sprache der Veröffentlichung: | Englisch |
Titel des übergeordneten Werkes / der Zeitschrift (Englisch): | PLoS One |
Erscheinungsjahr: | 2021 |
Band / Jahrgang: | 16 |
Heft / Ausgabe: | 8 |
Aufsatznummer: | e0255341 |
Originalveröffentlichung / Quelle: | PLoS One (2021) 16:8, e0255341. https://doi.org/10.1371/journal.pone.0255341 |
DOI: | https://doi.org/10.1371/journal.pone.0255341 |
Allgemeine fachliche Zuordnung (DDC-Klassifikation): | 6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit |
Freie Schlagwort(e): | electromagnetics; linear regression analysis; magnetic resonance imaging; optimization; power grids; swine; thorax; wave interference |
Datum der Freischaltung: | 02.05.2022 |
Sammlungen: | Open-Access-Publikationsfonds / Förderzeitraum 2021 |
Lizenz (Deutsch): | CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International |