An eight‐channel sodium/proton coil for brain MRI at 3 T

Abstract

The purpose of this work is to illustrate a new coil decoupling strategy and its application to a transmit/receive sodium/proton phased array for magnetic resonance imaging (MRI) of the human brain. We implemented an array of eight triangular coils that encircled the head. The ensemble of coils was arranged to form a modified degenerate mode birdcage whose eight shared rungs were offset from the z-axis at interleaved angles of ±30°. This key geometric modification resulted in triangular elements whose vertices were shared between next-nearest neighbors, which provided a convenient location for counter-wound decoupling inductors, whilst nearest-neighbor decoupling was addressed with shared capacitors along the rungs. This decoupling strategy alleviated the strong interaction that is characteristic of array coils at low frequency (32.6 MHz in this case) and allowed the coil to operate efficiently in transceive mode. The sodium array provided a 1.6-fold signal-to-noise ratio advantage over a dual-nuclei birdcage coil in the center of the head and up to 2.3-fold gain in the periphery. The array enabled sodium MRI of the brain with 5-mm isotropic resolution in approximately 13 min, thus helping to overcome low sodium MR sensitivity and improving quantification in neurological studies. An eight-channel proton array was integrated into the sodium array to enable anatomical imaging.

X‐nuclei imaging: Current state, technical challenges, and future directions

“…By avoiding coil exchange between measurements, patient comfort is increased, and the total measurement time is reduced. Various 23 Na coil designs have been presented for head, breast, and knee applications. Solutions for synchronous acquisition of 23 Na and 1 H signal have been developed .…”

Double‐tuned 31P/1H human head array with high performance at both frequencies for spectroscopic imaging at 9.4T

“…There are several previously reported DT UHF head array coil designs . To the best of our knowledge, a 4‐layer DT array coil consisting of 2 double‐layer ToRo‐setups (both X‐nuclei and 1 H) has never yet been reported due to its high complexity.…”

“…To the best of our knowledge, a 4‐layer DT array coil consisting of 2 double‐layer ToRo‐setups (both X‐nuclei and 1 H) has never yet been reported due to its high complexity. Commonly, DT human head array coils consist of 2 or 3 layers . The double‐layer design contains 2 TxRx volume coils or TxRx arrays.…”

Magnetic Resonance Imaging of Phosphocreatine and Determination of BOLD Kinetics in Lower Extremity Muscles using a Dual-Frequency Coil Array

“…Recently, phased array coils have been designed to combine the SNR of surface coils with the volumetric coverage of birdcage coils for low SNR, non-proton applications 15 16 17 18 19 20 21 22 23 24 25 26 27 . In this study, we developed and evaluated a 31 P/ 1 H array for lower extremity MRI.…”