title: Robust imaging of hippocampal inner structure at 7T: in vivo acquisition protocol and methodological choices.
abstract: OBJECTIVE
  Motion-robust multi-slab imaging of hippocampal inner structure in vivo at 7T.
  
  
  METHODS
  Motion is a crucial issue for ultra-high resolution imaging, such as can be achieved with 7T MRI. An acquisition protocol was designed for imaging hippocampal inner structure at 7T. It relies on a compromise between anatomical details visibility and robustness to motion. In order to reduce acquisition time and motion artifacts, the full slab covering the hippocampus was split into separate slabs with lower acquisition time. A robust registration approach was implemented to combine the acquired slabs within a final 3D-consistent high-resolution slab covering the whole hippocampus. Evaluation was performed on 50 subjects overall, made of three groups of subjects acquired using three acquisition settings; it focused on three issues: visibility of hippocampal inner structure, robustness to motion artifacts and registration procedure performance.
  
  
  RESULTS
  Overall, T2-weighted acquisitions with interleaved slabs proved robust. Multi-slab registration yielded high quality datasets in 96 % of the subjects, thus compatible with further analyses of hippocampal inner structure.
  
  
  CONCLUSIONS
  Multi-slab acquisition and registration setting is efficient for reducing acquisition time and consequently motion artifacts for ultra-high resolution imaging of the inner structure of the hippocampus.
authors.affiliation: UPMC Univ Paris 06, UMR S 1127, ICM, Sorbonne Universités, 75013, Paris, France. linda.marrakchi@gmail.com.|Inserm, U1127, 75013, Paris, France. linda.marrakchi@gmail.com.|CNRS, UMR 7225, 75013, Paris, France. linda.marrakchi@gmail.com.|ICM, 75013, Paris, France. linda.marrakchi@gmail.com.|Inria Paris-Rocquencourt, 75013, Paris, France. linda.marrakchi@gmail.com.|Institut Supérieur de Biotechnologies de Sidi Thabet, Ariana-Tunis, Tunisia. linda.marrakchi@gmail.com.
authors.forename: Linda
authors.initials: L
authors.lastname: Marrakchi-Kacem
authors.affiliation: UNIRS, NeuroSpin, I2BM, DSV, CEA, Saclay, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Vignaud
authors.affiliation: Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, USA.
authors.forename: Julien
authors.initials: J
authors.lastname: Sein
authors.affiliation: UPMC Univ Paris 06, UMR S 1127, ICM, Sorbonne Universités, 75013, Paris, France.|Inserm, U1127, 75013, Paris, France.|CNRS, UMR 7225, 75013, Paris, France.|ICM, 75013, Paris, France.|Inria Paris-Rocquencourt, 75013, Paris, France.
authors.forename: Johanne
authors.initials: J
authors.lastname: Germain
authors.affiliation: Department of Neurology, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Henry
authors.affiliation: UNIRS, NeuroSpin, I2BM, DSV, CEA, Saclay, France.
authors.forename: Cyril
authors.initials: C
authors.lastname: Poupon
authors.affiliation: UNIACT, NeuroSpin, I2BM, DSV, CEA, Saclay, France.|INSERM U1129, Paris, France.|Paris-Descartes University, CEA, Gif sur Yvette, France.
authors.forename: Lucie
authors.initials: L
authors.lastname: Hertz-Pannier
authors.affiliation: UPMC Univ Paris 06, UMR S 1127, ICM, Sorbonne Universités, 75013, Paris, France.|Inserm, U1127, 75013, Paris, France.|CNRS, UMR 7225, 75013, Paris, France.|ICM, 75013, Paris, France.|Centre de Neuro-Imagerie de Recherche CENIR, AP-HP, Hopital de la Pitie Salpetriere, Paris, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Lehéricy
authors.affiliation: UPMC Univ Paris 06, UMR S 1127, ICM, Sorbonne Universités, 75013, Paris, France.|Inserm, U1127, 75013, Paris, France.|CNRS, UMR 7225, 75013, Paris, France.|ICM, 75013, Paris, France.|Inria Paris-Rocquencourt, 75013, Paris, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Colliot
authors.affiliation: Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, USA.
authors.forename: Pierre-François
authors.initials: PF
authors.lastname: Van de Moortele
authors.affiliation: UPMC Univ Paris 06, UMR S 1127, ICM, Sorbonne Universités, 75013, Paris, France.|Inserm, U1127, 75013, Paris, France.|CNRS, UMR 7225, 75013, Paris, France.|ICM, 75013, Paris, France.|Inria Paris-Rocquencourt, 75013, Paris, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Chupin
mesh_terms: D000465:Algorithms; D016477:Artifacts; D001931:Brain Mapping / Q000379:methods*; D064368:Healthy Volunteers; D006624:Hippocampus / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009038:Motion; D015995:Prevalence; D015203:Reproducibility of Results
keywords: Anatomical contrasts; Hippocampal formation; Inner structure of the hippocampus; Registration; Ultra-high field imaging