Eugene Milshteyn1,2, Georgy Guryev3, Angel Torrado-Carvajal1,2,4, Jacob K. White3, Lawrence L. Wald1,2,5, and Bastien Guerin1,2
1Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States, 2Harvard Medical School, Boston, MA, United States, 3Dept. of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 4Medical Image Analysis and Biometry Laboratory, Universidad Rey Juan Carlos, Madrid, Spain, 5Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, United States
1Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States, 2Harvard Medical School, Boston, MA, United States, 3Dept. of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 4Medical Image Analysis and Biometry Laboratory, Universidad Rey Juan Carlos, Madrid, Spain, 5Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, United States
This study focuses on developing a fast methodology for patient-specific SAR calculations with an 8 channel pTx head coil at 7T. This methodology consists of fast acquisition, segmentation, and electromagnetic analysis.
Figure 1: A. Flow chart depicting our methodology for fast computation of the patient-specific B1+ and SAR maps. B. 7T 8 channel pTx coil model simulated in this work and loaded with a body model for one of the volunteers. The body is extended 100 mm beyond the edge of the coil to eliminate any potential current “pseudo-loops” (11) that would affect the electromagnetic calculations.
Figure 4: Simulated and acquired B1+ maps for all 8 channels for three of the volunteers. While the simulated coil was not the same as the coil used for acquisition, both are 8 channel coils that comfortably conform to the volunteer head. The magnitude intensities shown were normalized. Qualitatively, the maps match up in terms of magnetic field distribution within the head. Future work will focus on being able to simulate and acquire with the same coil, which will allow more direct comparison of B1+ maps between simulation and acquisition, and be used as verification of the methodology.
