Motion-robust cardiac B1+ mapping at 3T using interleaved bloch-siegert shifts
Purpose To develop and evaluate a robust motion-insensitive Bloch-Siegert shift based mapping method in the heart. Methods Cardiac Bloch-Siegert mapping was performed with interleaved positive and negative off-resonance shifts and diastolic spoiled gradient echo imaging in 12 heartbeats. Numerical s...
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| Dokumenttyp: | Article (Journal) |
| Sprache: | Englisch |
| Veröffentlicht: |
2017
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| In: |
Magnetic resonance in medicine
Year: 2016, Jahrgang: 78, Heft: 2, Pages: 670-677 |
| ISSN: | 1522-2594 |
| DOI: | 10.1002/mrm.26395 |
| Online-Zugang: | Verlag, Volltext: http://dx.doi.org/10.1002/mrm.26395 Verlag, Volltext: https://onlinelibrary-wiley-com.ezproxy.medma.uni-heidelberg.de/doi/abs/10.1002/mrm.26395 
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| Verfasserangaben: | Sebastian Weingärtner, Fabian Zimmer, Gregory J. Metzger, Kâmil Uğurbil, Pierre-Francois Van de Moortele, and Mehmet Akçakaya |
| Zusammenfassung: | Purpose To develop and evaluate a robust motion-insensitive Bloch-Siegert shift based mapping method in the heart. Methods Cardiac Bloch-Siegert mapping was performed with interleaved positive and negative off-resonance shifts and diastolic spoiled gradient echo imaging in 12 heartbeats. Numerical simulations were performed to study the impact of respiratory motion. The method was compared with three-dimensional (3D) actual flip angle imaging (AFI) and two-dimensional (2D) saturated double angle method (SDAM) in phantom scans. Cardiac maps of three different views were acquired in six healthy volunteers using Bloch-Siegert and SDAM during breath-hold and free breathing. In vivo maps were evaluated for inter-view consistency using the correlation coefficients of the profiles along the lines of intersection between the views. Results For the Bloch-Siegert sequence, numerical simulations indicated high similarity between breath-hold and free breathing scans, and phantom results indicated low deviation from the 3D AFI reference (normalized root mean square error [NRMSE] = 2.0%). Increased deviation was observed with 2D SDAM (NRMSE = 5.0%) due to underestimation caused by imperfect excitation slice profiles. Breath-hold and free breathing Bloch-Siegert in vivo maps were visually comparable with no significant difference in the inter-view consistency (P > 0.36). SDAM showed strongly impaired map quality during free breathing. Inter-view consistency was significantly lower than with the Bloch-Siegert method (breath-hold: P = 0.014, free breathing: P < 0.0001). Conclusion The proposed interleaved Bloch-Siegert sequence enables cardiac mapping with improved inter-view consistency and high resilience to respiratory motion. |
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| Beschreibung: | Gesehen am 17.07.2018 Im Titel ist "1" tiefgestellt, "+" hochgestellt Published online 7 September 2016 |
| Beschreibung: | Online Resource |
| ISSN: | 1522-2594 |
| DOI: | 10.1002/mrm.26395 |