T1-weighted fMRI in mouse visual cortex at 0.1 mm resolution using a UTE sequence after iron-oxide contrast injection

Motivation: Conventional use of typical T2* weighted sequences such as FLASH post iron-oxide contrast injection exhibits an enhanced microvascular weighting but neglects changes in pial vessels due to strong dephasing defects. Goal(s): Our goal is to study changes in the pial vessels which will hopefully aid in the interpretation of non-BOLD fMRI signals and help us understand the CBV fMRI signal at a deeper level. Approach: We utilised a radial UTE sequence post-contrast injection with short TE and short readout duration Results: We found consistent positive signal changes in the visual cortex and pial surface. Impact: We found positive signal changes at the pial surface and in the visual cortex upon stimulation. This might indicate the involvement of both micro- and macrovasculature and provide further insights into cerebral-blood-volume changes across vascular compartments.