title: Flexible longitudinal magnetization contrast in spectrally overlapped 3D-MSI metal artifact reduction sequences: Technical considerations and clinical impact.
abstract: OBJECTIVE
  It has previously been demonstrated that increased overlap of spectral bins in three-dimensional multispectral imaging techniques (3D-MSI) can aid in reducing residual artifacts near metal implants. However, increasing spectral overlap also necessitates consideration of saturation effects for species with long T1 values. Here, an interleaved spectral bin acquisition strategy is presented for overlapping 3D-MSI that allows for flexible choice of repetition times while simultaneously addressing these cross talk concerns.
  
  
  METHODS
  A phantom imaging experiment is used to illustrate the amplified effect of cross talk on 3D-MSI acquisitions. A methodological approach to address cross talk across a variety of prescribed repetition times is then described. Using the presented principles, a clinical subject with a total hip replacement was imaged to generate T1, proton density, and short-tau inversion recovery contrasts. In addition, a fracture instrumentation case was imaged pre- and postcontrast using T1-weighted spectrally overlapped 3D-MSI.
  
  
  RESULTS
  Phantom results demonstrate that conventional spectral interleaving approaches can generate unwanted signal characteristics in heavily overlapped 3D-MSI. Clinical images using the presented methods successfully demonstrate T1, proton density, and inversion recovery image contrasts using heavily overlapped 3D-MSI.
  
  
  CONCLUSIONS
  Through automated management of spectral bin distributions across multiple interleaves, a variety of longitudinal magnetization contrasts can efficiently be acquired without any clinically relevant cross-talk impact using heavily overlapped 3D-MSI.
authors.affiliation: Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.|Department of Radiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Koch
authors.affiliation: Hospital for Special Surgery, Magnetic Resonance Imaging, New York, New York, USA.
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Koff
authors.affiliation: Hospital for Special Surgery, Magnetic Resonance Imaging, New York, New York, USA.
authors.forename: Parina H
authors.initials: PH
authors.lastname: Shah
authors.affiliation: GE Healthcare, Milwaukee, Wisconsin, USA.
authors.forename: Adriana
authors.initials: A
authors.lastname: Kanwischer
authors.affiliation: GE Healthcare, Milwaukee, Wisconsin, USA.
authors.forename: Dawei
authors.initials: D
authors.lastname: Gui
authors.affiliation: Hospital for Special Surgery, Magnetic Resonance Imaging, New York, New York, USA.
authors.forename: Hollis G
authors.initials: HG
authors.lastname: Potter
mesh_terms: D000465:Algorithms; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008670:Metals / Q000737:chemistry*; D019047:Phantoms, Imaging; D019736:Prostheses and Implants
chemical_list: D008670:Metals
keywords: MRI of arthroplasty; image artifacts; metal implants