Direct control of the temperature rise in parallel transmission by means of temperature virtual observation points: Simulations at 10.5 Tesla.

摘要: Purpose A method using parallel transmission to mitigate B1+ inhomogeneity while explicitly constraining the temperature rise is reported and compared with a more traditional SAR-constrained pulse design. Methods Finite difference time domain simulations are performed on numerical human head model for 16-channel coil at 10.5 Tesla. Based set of presimulations, virtual observation point compression derived. This compact representation then used in nonlinear programming algorithm design under explicit constraints. Results In example time-of-flight sequence, radiofrequency performance some cases increased by factor two pulses, directly efficiently controlled. Pulse can be gained relaxing SAR constraints, but expense loss direct control temperature. Conclusion Given importance accurate safety ultrahigh field lack correspondence between temperature, this work motivates need thorough thermal studies normal vivo conditions. The tools presented here will possibly contribute safer efficient MR exams. Magn Reson Med, 2015. © 2015 Wiley Periodicals, Inc.