Improved Tx Efficiency in Mock Transcranial MRgFUS with Modified Transfer Medium & Transducer Ground at 3T: Improved Results with Updated Phantom

Motivation: In MRI at 3T, the typical configuration of MR-guided focused Ultrasound (MRgFUS) results in a dark band through the brain in MRI. Goal(s): We introduce an approach to significantly improving MRI in the whole brain in addition to removing the dark band artifact, demonstrating here with an improved phantom for better results. Approach: An improved phantom for experimental validation of our method was developed by using a spheroidal compartment rather than a hemispherical compartment to represent the head. Results: Transmit Efficiency was improved by more than a factor of 4 on average in the ROI using our proposed method. Impact: By strategically adjusting electric permittivity of the transfer medium and slotting the transducer ground plane, transmit efficiency of MRI in transcranial MRgFUS can be improved by a factor of up to 4 while also eliminating a well-known dark band.