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Spin‐echo and gradient‐echo epi of human brain activation using bold contrast: A comparative study at 1.5 T
Author(s) -
Bandettini Peter A.,
Wong Eric C.,
Jesmanowicz A.,
Hinks R. Scott,
Hyde James S.
Publication year - 1994
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1940070104
Subject(s) - nuclear magnetic resonance , spin echo , echo (communications protocol) , resting state fmri , human brain , contrast (vision) , gradient echo , chemistry , cortex (anatomy) , physics , magnetic resonance imaging , neuroscience , medicine , psychology , optics , computer network , computer science , radiology
In this study, Blood Oxygenation Level Dependent (BOLD) contrast in the detection of human brain activation was compared between spin‐echo and gradient‐echo echo‐planar sequences at 1.5 T. Time course series of spin‐echo and gradient‐echo images containing the primary motor cortex were collected during rest (no finger movement) and activation (finger movement). Each time course series was collected using a different TE . Resting and active state signal intensities at each TE were measured in identical regions in the motor cortex. From these data, resting and active state R 2 (1/ T 2 ) and R 2 *(1/ T 2 * ) values were obtained. Across four subjects, brain activation produced an average R 2 change of −0.16±0.02/s (±SE), and an average R 2 *change of −0.55±0.08/s. The average Δ R 2 * /Δ R 2 ratio was 3.52±0.56. The average gradient‐echo/spin‐echo ratio of activation‐induced signal changes at the TE for maximal BOLD contrast for each sequence ( TE ≈ T 2 *and T 2 ) was calculated to be 1.87±0.40.