The Origins of FMRI Contrast in SPEN Imaging at Ultra High Magnetic Fields

Eddy Solomon¹, Nadya Pyatigorskaya², Peter Bendel¹, Denis Le Bihan², Luisa Ciobanu², Lucio Frydman¹

This presentation examines the origin of the function-derived activation detected by SPEN fMRI, with a series of preclinical high (7T) and ultra-high (17.2T) magnetic field studies. Artifact-free images of a rats head with good resolution in all areas and localized activation maps were obtained in a single scan using a variety of SPEN sequences. Our data shows that, besides the normal T2*-weighted BOLD contribution which arises in non-refocused sequences, fMRI SPEN signals contains a strong component caused by apparent T1-related inflow effects. This contribution can be modulated by varying the scanning repetition rate; measurements at 7T support this finding.