Local and whole-body SAR in UHF body imaging: Implications for SAR matrix compression.

For transmit antenna arrays used for body imaging at 7 T as well as for the 3 T birdcage, all evaluated cases show that the local SAR limit was reached before reaching the whole-body SAR limit. Nevertheless, the whole-body SAR matrix can be used to reduce the number of local SAR matrices, which is important to reduce memory and computing time for a virtual observation points (VOP) compression. This step can be included as a pre-compression prior to a VOP compression.