Dependence of amygdala activation on echo time: results from olfactory fMRI experiments.
Echo time dependence of the BOLD sensitivity is an important topic in fMRI whenever brain regions are considered where the EPI data quality suffers from susceptibility gradients. Here, an fMRI study is presented showing that a reduced echo time EPI sequence significantly enhances the statistical inference in subcortical (limbic) brain regions, with special focus on the amygdala. As a consequence, to facilitate whole-brain fMRI with optimal echo times, a sequence with slice-dependent echo time is demonstrated with a focus on structures suffering from susceptibility changes. The applicability of this method is shown in a second fMRI study aimed at both, cortical, and limbic brain regions. The results are in good agreement with theoretical descriptions of the BOLD sensitivity under the influence of susceptibility gradients.
Stöcker
Tony
T
Institut für Medizin, Forschungszentrum Jülich, 52425 Jülich, Germany.
Kellermann
Thilo
T
Schneider
Frank
F
Habel
Ute
U
Amunts
Katrin
K
Pieperhoff
Peter
P
Zilles
Karl
K
Shah
N Jon
NJ
D000328:Adult; D000679:Amygdala / Q000502:physiology*; D016477:Artifacts; D001921:Brain / Q000502:physiology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology; D017352:Echo-Planar Imaging; D004644:Emotions / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008432:Mathematical Computing; D008570:Memory, Short-Term / Q000502:physiology; D015233:Models, Statistical; D010100:Oxygen / Q000097:blood; D012016:Reference Values; D012680:Sensitivity and Specificity; D012903:Smell / Q000502:physiology*; D013997:Time Factors
D010100:Oxygen