Purpose: To demonstrate mesoscale whole-brain T2*-weighted (T2*w) MRI at 10.5 T, quantify R2* relaxation rate and magnetic susceptibility (χ), and evaluate T2*w contrast at such high field strength.
Methods: Multi-echo GRE (ME-GRE) data were collected in healthy adults at 0.5 mm isotropic resolution at 10.5 T. Whole-brain images were reconstructed with navigator-guided joint motion and field correction and were used for quantitative R2* and χ mapping. Regional R2* and χ values and R2* contrast were analyzed in volumetric regions of interest (ROIs) and intra-cortical surface-based ROIs. For comparison, ME-GRE data from the same subjects were acquired using a similar protocol at 7 T.
Results: High-quality whole-brain T2*w images were obtained, enabling R2* and χ mapping with delineation of fine-scale brain structures. Regional R2* analysis revealed a linear relationship between 10.5 T and 7 T R2* values with a slope of 1.52, in agreement with previously reported linear field dependency of R2*. Estimated χ values were field-independent in most brain regions under consideration except for the basal ganglia where χ was observed to be lower at 10.5 T than at 7 T. The normalized R2* contrast that is, the R2* difference normalized by the mean R2*, increased by about 3% between brain regions and 12% between cortical depths from 7 to 10.5 T.
Conclusion: It is feasible to achieve high-quality mesoscale whole-brain T2*w MRI at 10.5 T and associated quantitative R2* and χ mapping. Our results may aid future optimization of anatomic T2*w brain MRI at ultrahigh field beyond 7 T.
Keywords: 10.5 T; R2* relaxation rate; T2*‐weighted MRI; magnetic susceptibility χ; mesoscale whole‐brain MRI; ultrahigh field MRI.
© 2026 The Author(s). Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.