The Specific Absorption Rate (SAR) is a limiting factor to all MRI-scans. Especially at ultra-high magnetic fields (≥ 7 Tesla), it imposes a significant constraint in the design of pulse sequences....Show moreThe Specific Absorption Rate (SAR) is a limiting factor to all MRI-scans. Especially at ultra-high magnetic fields (≥ 7 Tesla), it imposes a significant constraint in the design of pulse sequences. Due to interpatient variability and the complicated structure of human anatomy, it is difficult to accurately determine the exact SAR-distribution for individual patients. Computational simulations using high-resolution human body models can be used to estimate the SAR, but such models are not available for individual patients in a clinical setting. Here, a method for developing a personalized model for estimating SAR in the head using parallel transmission at 7 Tesla is proposed based on clustered segmentation of tissues. We found that by segmenting all the tissues in the head into fat, cerebrospinal fluid (CSF), grey matter, and bone, the peak-SAR can be determined with an error of less than 2.8 % of the overall peak-SAR. This result is shown to be reproducible for subjects of different ages and genders. Methods for the automated segmentation of this mapping in individual patients based on T1w-images, quantitative T1-mapping, and ultra-short TE-scans are proposed and tested experimentally. Using the proposed method, it should be possible to operate scanners closer to the true SAR-limits due to improved estimations of the actual patient-specific SAR.Show less