Silvia Mangia1, Ryan Chamberlain1, Federico De Martino1, 2, Steen Moeller1, Curt Corum1, Tae Kim3, Chaitanya Kalavagunta1, Shalom Michaeli1, Michael Garwood1, Seong-Gi Kim3, Kamil Ugurbil1
1CMRR - Dept. of Radiology, University of Minnesota, Minneapolis, MN, United States; 2Department of Cognitive Neuroscience, University of Maastricht, Maastricht, Netherlands; 3Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States
We applied in fMRI sweep imaging with Fourier transformation (SWIFT), which measures fast 3D brain coverage without producing echoes. The SWIFT signal increased in the human visual cortex by 3-5% during visual stimulation at 4T. In Vitro, no MRI contrast was observed with SWIFT on 5-mm tubes containing arterial or venous blood. However, the SWIFT signal decreased in the rat cortex during respiratory challenges at 9.4T, in spite of the local blood flow increase, thus likely reflecting decreased blood oxygenation in vivo. Other cellular events occurring during activation might contribute to the SWIFT functional contrast in addition to oxygenation changes.