A 16-ELEMENT PHASED-ARRAY HEAD COIL

Volume-array coils offer increased signal-to-noise ratio (SNR) over st andard volume coils near the array elements while preserving the SNR a t the center of the volume. As the number of array elements is increas ed, the SNR advantage as well as the complexity of actually constructi ng the array increases also. In this study, a 16-channel receive-only array for imaging of the brain is demonstrated and compared to a circu larly polarized (CP) head coil of similar shape and diameter. The arra y was formed from a 2 x 8 grid of square elements placed on a cylindri cal form. Mutual coupling was minimized by a combination of overlappin g element placement and current-reducing matching networks. Simultaneo us data acquisition from the 16 individual elements was performed usin g a four-channel receiver system with each channel time domain multipl exed by a factor of 4, Theoretical and experimental comparisons betwee n the array and a standard CP head coil show that the array offers an increase in SNR of nearly a factor of 3 near its surface while maintai ning a comparable SNR to that of the CP head coil in the center of the region of interest.