Assessing the potential of 7T and high-performance gradients for high-resolution R2* mapping in deep gray matter

Motivation: While conventional 7T systems provide increased SNR, their gradient systems lack the performance to acquire high-resolution GRE data with very fast sampling/many echoes. Goal(s): To leverage a 7T with high-performance gradients to acquire more echoes than on conventional 7T systems and assess the potential for high-resolution R2* mapping. Approach: Multi-echo GRE data with varying number of echoes was acquired at a 7T Terra.X Impulse Edition and 7T Plus. Conventional logarithmic-linear and advanced stretched exponential fits were performed. Results: Sampling more echoes enables fitting advanced models which yield lower R2* standard deviation and root-mean-squared-errors. Impact: Combining 7T with high-performance gradients enables high spatial and temporal resolution multi-echo GRE data. Hence, R2* mapping can be performed with novel multi-parametric fits, enabling new avenues in biophysical modeling as well as signal denoising and decomposition algorithms.