A pathway towards a two‐dimensional, bore‐mounted, volume body coil concept for ultra high‐field magnetic resonance imaging

作者：Sayım Gökyar, Henning U. Voss, Victor Taracila, Fraser Robb, Michael Bernico, Douglas A.C. Kelley, Douglas Ballon, Simone Winkler · 发表于：NMR in Biomedicine · 年份：2022 · DOI：10.1002/nbm.4802 · 被引用次数：7 · 研究领域：Advanced MRI Techniques and Applications、Advanced NMR Techniques and Applications、Atomic and Subatomic Physics Research

Lack of a body‐sized, bore‐mounted, radiofrequency (RF) body coil for ultrahigh field (UHF) magnetic resonance imaging (MRI) is one of the major drawbacks of UHF, hampering the clinical potential of the technology. Transmit field ( B 1 ) nonuniformity and low specific absorption rate (SAR) efficiencies in UHF MRI are two challenges to be overcome. To address these problems, and ultimately provide a pathway for the full clinical potential of the modality, we have designed and simulated two‐dimensional cylindrical high‐pass ladder (2D c‐HPL) architectures for clinical bore‐size dimensions, and demonstrated a simplified proof of concept with a head‐sized prototype at 7 T. A new dispersion relation has been derived and electromagnetic simulations were used to verify coil modes. The coefficient of variation (CV) for brain, cerebellum, heart, and prostate tissues after B 1 + shimming in silico is reported and compared with previous works. Three prototypes were designed in simulation: a head‐sized, body‐sized, and long body‐sized coil. The head‐sized coil showed a CV of 12.3%, a B 1 + efficiency of 1.33 μT/√W, and a SAR efficiency of 2.14 μT/√(W/kg) for brain simulations. The body‐sized 2D c‐HPL coil was compared with same‐sized transverse electromagnetic (TEM) and birdcage coils in silico with a four‐port circularly polarized mode excitation. Improved B 1 + uniformity (26.9%) and SAR efficiency (16% and 50% better than birdcage and TEM coils, respectively) in spherical phantoms was...