Abstract #1441

Evaluation of Maximum Local SAR for Parallel Transmission (PTx) Pulses Based on Pre-Calculated Field Data Using a Selected Subset of "Virtual Observation Points"

Matthias Gebhardt¹, Dirk Diehl², Elfar Adalsteinsson³, Lawrence L. Wald⁴, Gabriele Eichfelder⁵

¹Siemens Healthcare, Erlangen, Germany; ²Siemens Corporate Technology, Erlangen, Germany; ³Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States; ⁴Martinos Center for Biomedical Imaging, Harvard University, Charlestown, MA, United States; ⁵Applied Mathematics II, University of Erlangen-Nuremberg, Erlangen, Germany

This work addresses the complexity problem inherent in local SAR estimation for parallel transmission (pTx) and shows that a relatively small subset of carefully selected virtual observation points is adequate for prediction and control of maximum local SAR in pTx. We tested the proposed algorithm to detect local SAR maxima by comparison with an exhaustive search over local SAR distribution in numerical simulations of adult male and female subjects for an 8 channel whole body transmit array. The proposed method of model compression for local SAR successfully captured regions of local SAR maxima, but with dramatically reduced computation cost.