title: [Artifacts in MR imaging of the temporomandibular joint caused by dental alloys: a phantom model study at T1.5].
abstract: OBJECTIVE
  The influence of dental alloys on MRI of the temporomandibular joint was studied using a phantom model for this joint.
  
  
  METHODS
  At 1,5 T, 15 dental alloys and 14 of their most important components were investigated acquiring sagittal (FOV: 150 mm) and transverse (FOV: 250 mm) T1-weighted SE images. In 11 cases, T1- and T2*-weighted FLASH images were measured additionally. The artifacts were assessed qualitatively as well as quantitatively, and the samples were subdivided into four artifact categories.
  
  
  RESULTS
  Ag, Cu, Ga, In, Tl, Sn, Zn, amalgam, the precious alloys, the Au-Pd and Ag-Pd alloys showed no artifacts (category I). Minimal artifacts below 10 mm on transverse images (category II) were found for Cr, Pd, Pt and for the Ni-Cr alloy. Mn and the remaining non-precious alloys induced artifacts up to 30 mm (category III). Significant artifacts-more than 30 mm-(category IV) were caused by Ni-Cr and 18/8 wires and by Co, Fe, and Ni. T2*-weighted FLASH proved to be more susceptible for artifacts than T1-weighted SE and FLASH techniques.
  
  
  CONCLUSIONS
  In contrast to dental alloys for fixed prosthodontics, Ni-Cr- or 18/8 wires used for orthodontic bands can influence not only the image quality, but also the diagnostic reliability of MRI of the temporomandibular joint.
authors.affiliation: Institut für Röntgendiagnostik, Klinikum der Universität Regensburg.
authors.forename: C
authors.initials: C
authors.lastname: Fellner
authors.forename: M
authors.initials: M
authors.lastname: Behr
authors.forename: F
authors.initials: F
authors.lastname: Fellner
authors.forename: P
authors.initials: P
authors.lastname: Held
authors.forename: G
authors.initials: G
authors.lastname: Handel
authors.forename: S
authors.initials: S
authors.lastname: Feuerbach
mesh_terms: D016477:Artifacts; D003722:Dental Alloys; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation; D009969:Orthodontic Wires; D019047:Phantoms, Imaging; D011476:Prosthodontics; D013704:Temporomandibular Joint / Q000033:anatomy & histology*; D013705:Temporomandibular Joint Disorders / Q000175:diagnosis
chemical_list: D003722:Dental Alloys