TY  - JOUR
A1  - Orzada, Stephan
A1  - Fiedler, Thomas M.
A1  - Bitz, Andreas
A1  - Ladd, Mark E.
A1  - Quick, Harald H.
T1  - Local SAR compression with overestimation control to reduce maximum relative SAR overestimation and improve multi-channel RF array performance
T2  - Magnetic Resonance Materials in Physics, Biology and Medicine
N2  - Objective
In local SAR compression algorithms, the overestimation is generally not linearly dependent on actual local SAR. This can lead to large relative overestimation at low actual SAR values, unnecessarily constraining transmit array performance.

Method
Two strategies are proposed to reduce maximum relative overestimation for a given number of VOPs. The first strategy uses an overestimation matrix that roughly approximates actual local SAR; the second strategy uses a small set of pre-calculated VOPs as the overestimation term for the compression.

Result
Comparison with a previous method shows that for a given maximum relative overestimation the number of VOPs can be reduced by around 20% at the cost of a higher absolute overestimation at high actual local SAR values.

Conclusion
The proposed strategies outperform a previously published strategy and can improve the SAR compression where maximum relative overestimation constrains the performance of parallel transmission.
Y1  - 2020
UR  - https://opus.bibliothek.fh-aachen.de/opus4/frontdoor/index/index/docId/9371
SN  - 1352-8661
IS  - 34 (2021)
SP  - 153
EP  - 164
PB  - Springer
CY  - Heidelberg
ER  -