A Composite Decoupling Method for RF Transceiver Array Coils in MRI

Introduction Although widely embraced in clinical applications, array coils [1] still pose tremendous design challenges due to coupling between coil elements [2]. Several strategies have been proposed for eliminating mutual inductance, such as overlapping [1, 3], orthogonal positioning [3], use of low impedance preamplifiers [1], digital postprocessing [4], capacitive/inductive networks [5] and shielding design [6]. These strategies, however, have their own shortcomings that include either poor efficiency caused by interactions or implementation only in receiver array coils [7]. In addition, most strategies have been discussed only for decoupling two-channel array coils, assuming that the strategies would be extended easily to higher number of channels. This assumption is untrue in most cases, especially when decoupling cylindrical array coils in which the elements are physically much closer than in planar array coils. In this work, we present a composite scheme for minimizing the mutual inductance of transceiver array coils that have more than two channels, a strategy that combines a novel design for shielding-based decoupling with a method for simplified capacitive decoupling.