title: Efficient generation of T2*-weighted contrast by interslice echo-shifting for human functional and anatomical imaging at 9.4 Tesla.
abstract: OBJECTIVE
  Standard gradient-echo sequences are often prohibitively slow for T2*-weighted imaging as long echo times prolong the repetition time of the sequence. Echo-shifting offers a way out of this dilemma by allowing an echo time that exceeds the repetition time. The purpose of this work is to present a gradient-echo sequence that is optimized for multislice T2*-weighted imaging applications by combining echo-shifting with an interleaved slice excitation order.
  
  
  METHODS
  This combined approach offers two major advantages: First, it combines the advantages of both concepts, that is, echo time and pulse repetition time can be significantly increased without affecting scan time. Second, there is no echo-shifting related signal loss associated with this concept as only a single radiofrequency pulse is applied per pulse repetition time and slice.
  
  
  RESULTS
  A 9.4 Tesla high-resolution T2*-weighted anatomical brain scan of the proposed sequence is compared to a standard gradient-echo. Furthermore, results from 9.4 Tesla blood oxygen level dependent functional magnetic resonance imaging experiments with an in-plane resolution of 0.8 × 0.8 mm(2) are presented.
  
  
  CONCLUSIONS
  The proposed sequence allows for efficient generation of T2*-weighted contrast by combining echo-shifting with an interleaved slice excitation order.
authors.affiliation: Department of Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany.|High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Ehses
authors.affiliation: High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.
authors.forename: Jonas
authors.initials: J
authors.lastname: Bause
authors.affiliation: High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Shajan
authors.affiliation: Department of Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany.|High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Scheffler
mesh_terms: D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D064847:Multimodal Imaging / Q000379:methods; D010092:Oximetry / Q000379:methods; D010101:Oxygen Consumption / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio
keywords: T2*; echo‐shifting; fMRI; susceptibility‐weighted images; ultrahigh field