Single-channel, box-shaped, monopole-type antenna for B1+ field manipulation in conjunction with the traveling-wave concept in 9.4 T MRI
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We have developed a single-channel, box-shaped, monopole-type antenna which, if used in two different configurations, excites complementary B1+ field distributions in the traveling-wave setup.
Materials and methods
A new monopole-type, single-channel antenna for RF excitation in 9.4 T magnetic resonance imaging is proposed. The antenna is entirely made of copper without lumped elements. Two complementary B1+ field distributions of two different antenna configurations were measured and combined as a root sum of squares. B1+ field inhomogeneity of the combined maps was calculated and compared with published results.
By combining B1+ field distributions generated by two antenna configurations, a “no voids” pattern was achieved for the entire upper brain. B1+ inhomogeneity of approximately 20 % was achieved for sagittal and transverse slices; it was <24 % for coronal slices. The results were comparable with those from CP, with “no voids” in slice B1+ inhomogeneity of multichannel loop arrays. The efficiency of the proposed antenna was lower than that of a multichannel array but comparable with that of a patch antenna.
The proposed single-channel antenna is a promising candidate for traveling-wave brain imaging. It can be combined with the time-interleaved acquisition of modes (TIAMO) concept if reconfigurability is obtained with a single-antenna element.
Keywords9.4 T Transmit coil Time-interleaved acquisition of modes (TIAMO) High-field MRI
Conflict of interest
The authors declare that they have no conflict of interest.
The manuscript does not contain clinical studies or patient data.
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