title: Imaging of soft tissues adjacent to orthopedic hardware: comparison of 3-T and 1.5-T MRI.
abstract: OBJECTIVE
  The purpose of this study was to compare metal artifact reduction techniques at 1.5-T and 3-T MRI.
  
  
  METHODS
  A titanium plate with steel screws was placed in a freshly harvested pig leg. The leg was imaged with 1.5-T and 3-T MRI. A T2-weighted turbo spin-echo sequence was used with echo-train lengths of 8, 16, 32, and 64 and a constant readout bandwidth of 31.2 kHz. The images were compared qualitatively, and the optimal echo-train length was selected. Images were acquired at the optimal echo-train length with four different readout bandwidths. Artifact was measured quantitatively, and image quality was ranked qualitatively. The qualitatively best image acquired at 1.5 T was compared with the qualitatively highest-ranked image acquired at 3 T.
  
  
  RESULTS
  At both 1.5 T and 3 T, optimal images of equal quality were produced at echo-train lengths of 8 and 16. At higher readout bandwidths, there was quantitatively less artifact. The qualitatively best images were acquired at a readout bandwidth of 31.2 kHz at 1.5 T and 62.5 kHz at 3 T (Cronbach's alpha=1.00). The optimal image at 3 T was qualitatively superior to that at 1.5 T.
  
  
  CONCLUSIONS
  Optimizing image acquisition parameters in this phantom model resulted in similar quantitative susceptibility artifact at 3 T and 1.5 T and better qualitative images at 3 T than at 1.5 T.
authors.affiliation: Department of Radiology, Cappagh National Orthopaedic Hospital, Finglas, Dublin 11, Republic of Ireland. farrellycormac@gmail.com
authors.forename: Cormac
authors.initials: C
authors.lastname: Farrelly
authors.forename: Amir
authors.initials: A
authors.lastname: Davarpanah
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Brennan
authors.forename: Stephen
authors.initials: S
authors.lastname: Brennan
authors.forename: Mathew
authors.initials: M
authors.lastname: Sampson
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Eustace
mesh_terms: D000818:Animals; D016477:Artifacts; D001860:Bone Plates; D001863:Bone Screws; D006614:Hindlimb; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D013552:Swine; D014025:Titanium
chemical_list: D014025:Titanium