MR thermometry of RF heating in the human brain at 7T using the harmonical initialized multi-echo model with SVD-based motion correction

A multi-echo signal model was presented to measure RF-induced temperature rise in the brain at 7T. The proposed method corrects drift fields based on near-harmonic 2D reconstruction and is complemented by an SVD-based motion-correction scheme. The method was tested in 2 volunteers, showing a maximum temperature increase of 0.25 °C with a precision of 0.12 °C. The reliability of the results was strengthened by measurements in which a heating pad was placed on the forehead of one volunteer. This measurement and thermal simulations indicated that the heatpad induced considerably more heating in the brain (3.5 °C) than SAR-constrained RF exposure.