Dynamic Updates of R2* and Field Map in fMRI Using a Spiral-In Quick-Spiral-Out K-Space Trajectory
Olafsson V, Noll D, Fessler J
The University of Michigan
Collecting fMRI data using a fully sampled spiral-in spiral-out has been shown to give increased activation volumes. The spiral-in is more robust to susceptibility related signal dropouts, while the spiral-out increases BOLD-weighting. We propose to collect fMRI data using a fully sampled spiral-in and a spiral-out with 4-fold reduced FOV, but same resolution as the spiral-in. This increases temporal resolution without losing the advantage spiral-in spiral-out acquisition gives. The data was reconstructed using a joint reconstruction of the dynamic changes in R2* and field map. Results show a large increase in activation volumes relative to collecting only spiral-in data.