title: In vitro assessment of artifacts from commercially available markers for image-guided preoperative marking of bone and soft tissue lesions.
abstract: OBJECTIVE
  To evaluate the magnetic resonance (MR) imaging artifacts from several commercially available MR imaging-compatible and non-MR imaging-compatible markers for image-guided marking of soft tissue lesions at different field strengths and sequences.
  
  
  METHODS
  Ten different marking devices (anchor, coil, V, and X shapes) were injected into solid agar and imaged at two different field strengths (1.5 T, 3.0 T) and with three MR sequences (T1-weighted three-dimensional fast low-angle shot, T1-weighted two-dimensional fast low-angle shot MR fluoroscopy, and T2-weighted short inversion time inversion-recovery). Artifacts were assessed quantitatively by evaluating the areas of signal extinction and calculating equivalent diameters and qualitatively by visual grading. Paired t tests were used to assess the influence of sequence types and field strengths.
  
  
  RESULTS
  Artifact diameters ranged from negligible to 45.8 mm. Sequence types and field strength did not have a statistically relevant influence on the artifact size. All artifacts from non-MR imaging-compatible V- and X-shaped markers were rated as "too large;" the artifacts from MR imaging-compatible V- and X-shaped markers and from all anchor-shaped devices were rated as "too small." The highest ratings were achieved by an MR imaging-compatible coil-shaped marker.
  
  
  CONCLUSIONS
  The artifacts of the tested marking devices are mainly determined by their shapes and materials. Sequence types and field strengths have only a small influence on the artifacts. The most distinguished signal voids with an intermediate size resulted from an MR imaging-compatible coil-shaped marker.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University of Tübingen, Hoppe-Seyler Str 3, 72076 Tübingen, Germany. christoph.thomas@med.uni-tuebingen.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Thomas
authors.forename: Bernd M
authors.initials: BM
authors.lastname: Müller-Bierl
authors.forename: Hansjörg
authors.initials: H
authors.lastname: Rempp
authors.forename: Katja
authors.initials: K
authors.lastname: Siegmann
authors.forename: Petros
authors.initials: P
authors.lastname: Martirosian
authors.forename: Claus D
authors.initials: CD
authors.lastname: Claussen
authors.forename: Philippe L
authors.initials: PL
authors.lastname: Pereira
mesh_terms: D000818:Animals; D016477:Artifacts; D001859:Bone Neoplasms / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation*; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D019047:Phantoms, Imaging; D011300:Preoperative Care / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012983:Soft Tissue Neoplasms / Q000473:pathology* / Q000601:surgery; D025321:Surgery, Computer-Assisted / Q000379:methods*