Keywords:
Computer applications, MR physics, Paediatric, CT, Image manipulation / Reconstruction, MR, Computer Applications-3D, Radiation safety, Dosimetric comparison, Image verification
Authors:
M. Alhilani1, H. Jeong2, G. Ntolkeras2, S. R. Atefi2, L. Zöllei2, A. Pourvaziri2, M. H. Lev2, E. P. Grant2, G. Bonmassar2; 1London/GB, 2Boston, MA/US
DOI:
10.26044/ecr2021/C-10139
Results
The pilot use case for MRI RF safety simulation:
As an example of an MRI safety study of an Active Implantable Medical Device (AMID), we show the application of the new FDA TS 10974:2018 guidelines to a pediatric Vagus Nerve Stimulation (VNS) implant at 1.5T. Tier 3 and tier 4 simulations were performed using dielectric properties at 64 MHz that are appropriate for a 29-month-old child. The VNS lead was connected to an implantable pulse generator (IPG) and was placed inside MARTIN with the guidance of a neurologist. Electromagnetic field distribution changes in a child with and without a VNS implant were estimated using a head transmit coil, following the VNS/MRI labelling for adults. The investigation of AMID safety in children is of interest since the electromagnetic field distribution generated by the MRI differs from those in adult subjects. We compared the results of head averaged SAR from Martin with the results using Nina model,8 which were 0.2046 W/kg and 0.2068W/kg, corresponding only to marginal variations of 1.06%. Even though the variations are marginal, the anatomical inaccuracies of Nina not present in MARTIN, may lead to SAR peaks in mislabelled tissue.