| Zugriffsnummer | 34390 |
| Dokumenttyp | Konferenzartikel |
| Peer Review | unbekannt |
| Sprache | Englisch |
| Titel | A system for in situ S-parameter measurements of MR transmit arrays |
| Autor(in); Institution |
Weidemann, Gerd; 8.1, Medizinische Messtechnik, PTB-Berlin
Seifert, Frank; 8.1, Medizinische Messtechnik, PTB-Berlin
Hoffmann, Werner; 8.1, Medizinische Messtechnik, PTB-Berlin
Seemann, Reiner; 8.1, Medizinische Messtechnik, PTB-Berlin
Waxmann, Patrick; 8.1, Medizinische Messtechnik, PTB-Berlin
Ittermann, Bernd; 8.1, Medizinische Messtechnik, PTB-Berlin
|
| Quelle/Jahr | ISMRM 23th Annual Meeting & Exhibition: 30 May - 5 June, 2015; Toronto, Canada:(2015), 1 S. |
| Availability | [CD-ROM] ; file name: 1775.pdf |
| ISSN | 1545-4428 |
| Verlag | Berkeley, Calif.: ISMRM |
| Konferenzangaben | 23th ISMRM Annual Meeting & Exhibition, Toronto, 30 May – 5 June, 2015, Canada |
| Zusammenfassung | The S-parameter matrix of the 3T pTx coil shows low direct reflection but strong coupling to the next nearest neighbor (nnn) elements. Since the coil is not shielded it is quite sensitive to its surrounding. Placed inside a 38-cm shim insert and a few centimeters off axis, the direct reflection is increased and the coupling to the nnn elements is reduced. The elements closer to the shim insert become more detuned and a reflected amplitude of up to 0.59 (35% reflected power) is measured directly in the transmit channel. The power accepted by the coil is even lower than 65% because of additional losses in cables and Tx/Rx switch. The S-parameter matrix of the shielded 7T array shows a different characteristic. The direct reflection in the transmit channel is higher but the coupling decreases continuously with the distance of the element. |
