Implementation of Mode-Scanning Excitation Method with a 16-ch Transmit/Receive Volume Strip Array at 7T
Lee R, Xue R, Brown R, Stephanescu C, Wang Y, Mizsei G, Ibrahim T, Chang H
New York University
At high fields, especially 7T or above, the interaction between coil and sample is so pronounced that not only the sample loading has to be included in tuning (as in lower fields), but also the sample dielectric resonance has to be considered to determine the magnetic field pattern of the coil. The Mode-Scanning Excitation (MSE) method was previously proposed and simulated to obtain the desired transmit field pattern of any arbitrary sample inside a volume strip array (VSA) by inverse design of the voltage amplitudes and phases at transmit ports based on a set of pre-scan measurements. In this study, a 7T 16-ch transmit/receive coil and its 16-way transmit/receive RF interface was built to prove the feasibility of the MSE method. Our experimental results show that desired regional excitation patterns at specified locations can be achieved by MSE in presence of sample dielectric resonance.