title: Significant Artifact Reduction at 1.5T and 3T MRI by the Use of a Cochlear Implant with Removable Magnet: An Experimental Human Cadaver Study.
abstract: OBJECTIVE
  Cochlear implants (CIs) are standard treatment for postlingually deafened individuals and prelingually deafened children. This human cadaver study evaluated diagnostic usefulness, image quality and artifacts in 1.5T and 3T magnetic resonance (MR) brain scans after CI with a removable magnet.
  
  
  METHODS
  Three criteria (diagnostic usefulness, image quality, artifacts) were assessed at 1.5T and 3T in five cadaver heads with CI. The brain magnetic resonance scans were performed with and without the magnet in situ. The criteria were analyzed by two blinded neuroradiologists, with focus on image distortion and limitation of the diagnostic value of the acquired MR images.
  
  
  RESULTS
  MR images with the magnet in situ were all compromised by artifacts caused by the CI. After removal of the magnet, MR scans showed an unequivocal artifact reduction with significant improvement of the image quality and diagnostic usefulness, both at 1.5T and 3T. Visibility of the brain stem, cerebellopontine angle, and parieto-occipital lobe ipsilateral to the CI increased significantly after magnet removal.
  
  
  CONCLUSIONS
  The results indicate the possible advantages for 1.5T and 3T MR scanning of the brain in CI carriers with removable magnets. Our findings support use of CIs with removable magnets, especially in patients with chronic intracranial pathologies.
authors.affiliation: University Department of Diagnostic and Interventional Neuroradiology, Inselspital Bern, Bern, Switzerland.
authors.forename: Franca
authors.initials: F
authors.lastname: Wagner
authors.affiliation: University Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital Bern, Bern, Switzerland; ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland.
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Wimmer
authors.affiliation: University Department of Diagnostic and Interventional Neuroradiology, Inselspital Bern, Bern, Switzerland.
authors.forename: Lars
authors.initials: L
authors.lastname: Leidolt
authors.affiliation: University Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital Bern, Bern, Switzerland.
authors.forename: Mattheus
authors.initials: M
authors.lastname: Vischer
authors.affiliation: University Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital Bern, Bern, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Weder
authors.affiliation: University Department of Diagnostic and Interventional Neuroradiology, Inselspital Bern, Bern, Switzerland.
authors.forename: Roland
authors.initials: R
authors.lastname: Wiest
authors.affiliation: University Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital Bern, Bern, Switzerland.
authors.forename: Georgios
authors.initials: G
authors.lastname: Mantokoudis
authors.affiliation: University Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital Bern, Bern, Switzerland; ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland.
authors.forename: Marco D
authors.initials: MD
authors.lastname: Caversaccio
mesh_terms: D016477:Artifacts; D001921:Brain / Q000000981:diagnostic imaging*; D002102:Cadaver; D019929:Cochlear Implantation / Q000009:adverse effects / Q000295:instrumentation*; D020878:Device Removal / Q000009:adverse effects*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D059346:Magnets; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*