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Combined 23 Na and 13 C imaging at 3.0 Tesla using a single‐tuned large FOV birdcage coil
Author(s) -
Kaggie Joshua D.,
Lanz Titus,
McLean Mary A.,
Riemer Frank,
Schulte Rolf F.,
Benjamin Arnold J. V.,
Kessler Dimitri A.,
Sun Chang,
Gilbert Fiona J.,
Graves Martin J.,
Gallagher Ferdia A.
Publication year - 2021
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.28772
Subject(s) - electromagnetic coil , physics , nuclear magnetic resonance , nuclear medicine , medicine , quantum mechanics
Purpose An unmet need in carbon‐13 ( 13 C)‐MRI is a transmit system that provides uniform excitation across a large FOV and can accommodate patients of wide‐ranging body habitus. Due to the small difference between the resonant frequencies, sodium‐23 ( 23 Na) coil developments can inform 13 C coil design while being simpler to assess due to the higher naturally abundant 23 Na signal. Here we present a removable 23 Na birdcage, which also allows operation as a 13 C abdominal coil. Methods We demonstrate a quadrature‐driven 4‐rung 23 Na birdcage coil of 50 cm in length for both 23 Na and 13 C abdominal imaging. The coil transmit efficiencies and B 1 + maps were compared to a linearly driven 13 C Helmholtz‐based (clamshell) coil. SNR was investigated with 23 Na and 13 C data using an 8‐channel 13 C receive array within the 23 Na birdcage. Results The 23 Na birdcage longitudinal FOV was > 40 cm, whereas the 13 C clamshell was < 32 cm. The transmit efficiency of the birdcage at the 23 Na frequency was 0.65 µT/sqrt(W), similar to the clamshell for 13 C. However, the coefficient of variation of 23 Na‐ B 1 + was 16%, nearly half that with the 13 C clamshell. The 8‐channel 13 C receive array combined with the 23 Na birdcage coil generated a greater than twofold increase in 23 Na‐SNR from the central abdomen compared with the birdcage alone. Discussion This 23 Na birdcage coil has a larger FOV and improved B 1 + uniformity when compared to the widely used clamshell coil design while also providing similar transmit efficiency. The coil has the potential to be used for both 23 Na and 13 C imaging.