7T ultra-high field body MR imaging with an 8-channel transmit/32-channel receive radiofrequency coil array
Purpose In this work, a combined body coil array with eight transmit/receive (Tx/Rx) meander elements and with 24 receive-only (Rx) loops (8Tx/32Rx) was developed and evaluated in comparison with an 8-channel transmit/receive body array (8Tx/Rx) based on meander elements serving as the reference sta...
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| Hauptverfasser: | , |
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| Dokumenttyp: | Article (Journal) |
| Sprache: | Englisch |
| Veröffentlicht: |
21 April 2018
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| In: |
Medical physics
Year: 2018, Jahrgang: 45, Heft: 7, Pages: 2978-2990 |
| ISSN: | 2473-4209 |
| DOI: | 10.1002/mp.12931 |
| Online-Zugang: | Verlag, Volltext: https://doi.org/10.1002/mp.12931 Verlag: https://aapm.onlinelibrary.wiley.com/doi/abs/10.1002/mp.12931 
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| Verfasserangaben: | Stefan H.G. Rietsch, Stephan Orzada, Stefan Maderwald, Sascha Brunheim, Bart W. J. Philips, Tom W.J. Scheenen, Mark E. Ladd, Harald H. Quick |
| Zusammenfassung: | Purpose In this work, a combined body coil array with eight transmit/receive (Tx/Rx) meander elements and with 24 receive-only (Rx) loops (8Tx/32Rx) was developed and evaluated in comparison with an 8-channel transmit/receive body array (8Tx/Rx) based on meander elements serving as the reference standard. Methods Systematic evaluation of the RF array was performed on a body-sized phantom. Body imaging at 7T was performed in six volunteers in the body regions pelvis, abdomen, and heart. Coil characteristics such as signal-to-noise ratio, acceleration capability, g-factors, S-parameters, noise correlation, and B1+ maps were assessed. Safety was ensured by numerical simulations using a coil model validated by dosimetric field measurements. Results Meander elements and loops are intrinsically well decoupled with a maximum coupling value of −20.5 dB. Safe use of the 8Tx/32Rx array could be demonstrated. High gain in signal-to-noise ratio (33% in the subject's center) could be shown for the 8Tx/32Rx array compared to the 8Tx/Rx array. Improvement in acceleration capability in all investigations could be demonstrated. For example, the 8Tx/32Rx array provides lower g-factors in the right-left and anterior-posterior directions with R = 3 undersampling as compared to the 8Tx/Rx array using R = 2. Both arrays are very similar regarding their RF transmit performance. Excellent image quality in the investigated body regions could be achieved with the 8Tx/32Rx array. Conclusion In this work, we show that a combination of eight meander elements and 24 loop receive elements is possible without impeding transmit performance. Improved SNR and g-factor performance compared to an RF array without these loops is demonstrated. Body MRI at 7T with the 8Tx/32Rx array could be accomplished in the heart, abdomen, and pelvis with excellent image quality. |
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| Beschreibung: | Gesehen am 14.02.2020 |
| Beschreibung: | Online Resource |
| ISSN: | 2473-4209 |
| DOI: | 10.1002/mp.12931 |