@article{item_3283216,
  title = {{Electromagnetic simulation of a 16-channel head transceiver at 7 T using circuit-spatial optimization}},
  journal = {{Magnetic Resonance in Medicine}},
  abstract = {{Purpose: With increased interest in parallel transmission in ultrahigh-field MRI, methods are needed to correctly calculate the S-parameters and complex field maps of the parallel transmission coil. We present S-parameters paired with spatial field optimization to fully simulate a double-row 16-element transceiver array for brain MRI at 7 T. Methods: We implemented a closed-form equation of the coil S-parameters and overall spatial B+1 field. We minimized a cost function, consisting of coil S-parameters and the B+1 homogeneity in brain tissue, by optimizing transceiver components, including matching, decoupling circuits, and lumped capacitors. With this, we are able to compare the in silico results determined with and without B+1 homogeneity weighting. Using the known voltage range from the host console, we reconstructed the B+1 maps of the array and performed RF shimming with four realistic head models. Results: As performed with B+1 homogeneity weighting, the optimized coil circuit components were highly consistent over the four heads, producing well-tuned, matched, and decoupled coils. The mean peak forward powers and B+1 statistics for the head models are consistent with in vivo human results (N \textequals 8). There are systematic differences in the transceiver components as optimized with or without B+1 homogeneity weighting, resulting in an improvement of 28.4 $\pm$ 7.5\textpercent in B+1 homogeneity with a small 1.9 $\pm$ 1.5\textpercent decline in power efficiency. Conclusion: This co-simulation methodology accurately simulates the transceiver, predicting consistent S-parameters, component values, and B+1 field. The RF shimming of the calculated field maps match the in vivo performance.}},
  volume = {85},
  number = {6},
  pages = {3463--3478},
  publisher = {Wiley-Liss},
  address = {New York},
  year = {2021},
  slug = {item_3283216},
  author = {Li, X and Pan, JW and Avdievich, NI and Hetherington, HP and Rispoli, JV}
}