title: Experience with magnetic resonance imaging of human subjects with passive implants and tattoos at 7 T: a retrospective study.
abstract: OBJECTIVE
  Over the last decade, the number of clinical MRI studies at 7 T has increased dramatically. Since only limited information about the safety of implants/tattoos is available at 7 T, many centers either conservatively exclude all subjects with implants/tattoos or have started to perform dedicated tests for selected implants. This work presents our experience in imaging volunteers with implants/tattoos at 7 T over the last seven and a half years.
  
  
  METHODS
  1796 questionnaires were analyzed retrospectively to identify subjects with implants/tattoos imaged at 7 T. For a total of 230 subjects, the type of local transmit/receive RF coil used for examination, imaging sequences, acquisition time, and the type of implants/tattoos and their location with respect to the field of view were documented. These subjects had undergone examination after careful consideration by an internal safety panel consisting of three experts in MR safety and physics.
  
  
  RESULTS
  None of the subjects reported sensations of heat or force before, during, or after the examination. None expressed any discomfort related to implants/tattoos. Artifacts were reported in 52% of subjects with dental implants; all artifacts were restricted to the mouth area and did not affect image quality in the brain parenchyma.
  
  
  CONCLUSIONS
  Our initial experience at 7 T indicates that a strict rejection of subjects with tattoos and/or implants is not justified. Imaging can be conditionally performed in carefully selected subjects after collection of substantial safety information and evaluation of the detailed exposure scenario (RF coil/type and position of implant). Among the assessed subjects with tattoos, no side effects from the exposure to 7 T MRI were reported.
authors.affiliation: Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany. noureddine@mrcomp.com.|MR:comp GmbH, MR Safety Testing Laboratory, Gelsenkirchen, Germany. noureddine@mrcomp.com.
authors.forename: Yacine
authors.initials: Y
authors.lastname: Noureddine
authors.affiliation: Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany.|Division of Medical Physics in Radiology (E020), German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Andreas K
authors.initials: AK
authors.lastname: Bitz
authors.affiliation: Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany.|Division of Medical Physics in Radiology (E020), German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Ladd
authors.affiliation: Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany.|Department of Neurology, University Hospital, University Duisburg-Essen, Essen, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Thürling
authors.affiliation: Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany.|Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital, University Duisburg-Essen, Essen, Germany.
authors.forename: Susanne C
authors.initials: SC
authors.lastname: Ladd
authors.affiliation: MR:comp GmbH, MR Safety Testing Laboratory, Gelsenkirchen, Germany.
authors.forename: Gregor
authors.initials: G
authors.lastname: Schaefers
authors.affiliation: Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Kraff
mesh_terms: D016477:Artifacts; D000075202:Contraindications; D004869:Equipment Safety; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D061214:Patient Safety; D019736:Prostheses and Implants; D011846:Radio Waves; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D013653:Tattooing
keywords: 7 T; Implants; MR safety; MRI; Tattoos; UHF; Ultra-high-field