title: Memory-related hippocampal activity can be measured robustly using FMRI at 7 tesla.
abstract: High field strength functional magnetic resonance imaging (fMRI) has developed rapidly. However, it suffers from increased artifacts in brain regions such as the medial temporal lobe (MTL), challenging functional imaging of the hippocampus with the objective of high-spatial resolution, which is particularly useful for this region both from a clinical and cognitive neuroscience perspective. We set out to compare a BOLD sequence at 7 T versus 3 T to visualize the MTL activity during an associative memory-encoding task. Twenty-eight healthy volunteers underwent a blocked-design fMRI at either 3 T or 7 T while performing a face-profession associative memory encoding task. Qualitative analyses of overall image quality revealed that functional images at 7 T were of high quality, showing a good white/gray matter contrast, with reasonably acceptable signal dropouts and artifacts at the lower portion of the temporal lobe. Analyses of task-related fMRI data revealed robust activations in the bilateral MTL during associative memory encoding at both field strengths. Notably, we observed significantly stronger memory-related hippocampal activation at 7 T than at 3 T, suggesting higher BOLD sensitivity at 7 T. These results are discussed in the light of the feasibility of 7 T scanning protocols for the MTL.
authors.affiliation: University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen, Germany; University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany.
authors.forename: Nina
authors.initials: N
authors.lastname: Theysohn
authors.forename: Shaozheng
authors.initials: S
authors.lastname: Qin
authors.forename: Stefan
authors.initials: S
authors.lastname: Maderwald
authors.forename: Benedikt A
authors.initials: BA
authors.lastname: Poser
authors.forename: Jens M
authors.initials: JM
authors.lastname: Theysohn
authors.forename: Mark E
authors.initials: ME
authors.lastname: Ladd
authors.forename: David G
authors.initials: DG
authors.lastname: Norris
authors.forename: Elke R
authors.initials: ER
authors.lastname: Gizewski
authors.forename: Guillen
authors.initials: G
authors.lastname: Fernandez
authors.forename: Indira
authors.initials: I
authors.lastname: Tendolkar
mesh_terms: D000328:Adult; D001245:Association Learning / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008568:Memory / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: 7T; Hippocampus; fMRI; memory; ultra-high field strength MRI