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Abstract #3877

RF Exposure and Resulting Temperature in the Fetus During MRI

Jeff W. Hand1, Yan Li1, Jo V. Hajnal1

1Imaging Sciences Dept, Clinical Sciences Centre, Imperial College London, London W12 0NN, United Kingdom

SAR and temperature in a 26 week pregnant woman within a 64 MHz birdcage coil are predicted numerically. Heat transfer from fetus to placenta via the umbilical vein and arteries as well as that across the fetal skin/amniotic fluid /uterine wall boundaries is modelled. Fetal SAR and average temperature comply with international limits when maternal whole body SAR ≤2 W kg-1, although maximum fetal temperature > 38oC may result from continuous exposure over periods ≥7.5 minutes. However, assessment of risk posed by the maximum temperature predicted in a static model is difficult in view of frequent fetal movement.