Spin-echo fMRI provides greater functional specificity than gradient-echo fMRI, but suffers from lower sensitivity. At higher field strengths, the spin-echo signal contribution from smaller capillaries, closer to the site of neural activity, increases. A major challenge of MRI at high field strengths, however, is increased B1 inhomogeneity, which can impact the performance of RF pulses, in particular refocusing pulses. Here, we use an adiabatic refocusing pulse and a matched-phase excitation pulse to perform high-resolution spin-echo fMRI at 7T. We compare the results to a similar gradient-echo acquisition, and show sharper activation better localized to gray matter in the spin-echo results.
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