Validity of Transfer Function (TF) Model for Partial in Partial out (PIPO) Device under Different MR Radio Frequencies

Motivation: To ensure the MR RF safety of partial in partial out (PIPO) implantable devices using transfer function (TF) characterization. Goal(s): To determine the validity of the TF models for PIPO devices along various lead position at radio frequencies for 1.5T, 3T, 7T, and 10.5T MRI systems. Approach: By doing experimental measurements and error estimation to validate TF characterization of PIPO devices in different lead trajectories at difference rerequencies. Results: For 1.5T and 3T frequencies, the TF models are trajectory independent; for 7T and 10.5T frequencies, large variations in TF models were observed when the lead was positioned along different trajectories. Impact: The reliability of TF method characterization of PIPO devices is confirmed for frequencies below 128 MHz (3T) and TF method becomes error-proned at very high field MRI frequencies.