title: Prevalence and complications of MRI scans of cochlear implant patients : English version.
abstract: BACKGROUND
  Cochlear implants (CI) are the preferred method of treatment for patients with severe to profound bilateral sensorineural hearing loss and unilateral deafness. For many years, because of the magnetic field applied during magnetic resonance imaging (MRI) examinations, MRI examinations were contraindicated for CI patients or feasible only under specific circumstances. MRI examinations of CI recipients entail complications and therefore preventive measures have to be considered. The aim of this study was to evaluate the prevalence of MRI scans in CI recipients and the occurrence of complications and furthermore to investigate the preventive measures taken in radiological daily routine.
  
  
  METHODS
  A retrospective questionnaire was sent to 482 patients that received CIs from 1999-2013. Details of the MRI examination and subjective and objective incidents during and after the MRI scan were evaluated.
  
  
  RESULTS
  A total of 204 CI recipients answered the retrospective questionnaire (42.3 %). Twenty patients (9.8 %) with 23 implants underwent a total of 33 MRI scans with their cochlear implant in place. In 16 cases the scanned region was the head (49 %). Preventive measures in the form of head bandages were taken in 20 cases (61 %). The most common complication was pain in 23 cases (70 %) and the most serious complication was the dislocation of the internal magnet in 3 cases (9 %).
  
  
  CONCLUSIONS
  The number of CI recipients undergoing MRI scans is high. Possible complications and preventive measures attract too little attention in radiological daily routine.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Unfallkrankenhaus Berlin, Warener Str. 7, 12683, Berlin, Deutschland. gloria.grupe@charite.de.
authors.forename: G
authors.initials: G
authors.lastname: Grupe
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Unfallkrankenhaus Berlin, Warener Str. 7, 12683, Berlin, Deutschland.
authors.forename: J
authors.initials: J
authors.lastname: Wagner
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Unfallkrankenhaus Berlin, Warener Str. 7, 12683, Berlin, Deutschland.
authors.forename: S
authors.initials: S
authors.lastname: Hofmann
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Unfallkrankenhaus Berlin, Warener Str. 7, 12683, Berlin, Deutschland.
authors.forename: A
authors.initials: A
authors.lastname: Stratmann
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Unfallkrankenhaus Berlin, Warener Str. 7, 12683, Berlin, Deutschland.
authors.forename: P
authors.initials: P
authors.lastname: Mittmann
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Unfallkrankenhaus Berlin, Warener Str. 7, 12683, Berlin, Deutschland.
authors.forename: A
authors.initials: A
authors.lastname: Ernst
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Unfallkrankenhaus Berlin, Warener Str. 7, 12683, Berlin, Deutschland.
authors.forename: I
authors.initials: I
authors.lastname: Todt
mesh_terms: D000328:Adult; D000368:Aged; D002058:Burns, Electric / Q000453:epidemiology*; D003054:Cochlear Implants / Q000706:statistics & numerical data*; D015897:Comorbidity; D000075202:Contraindications; D004868:Equipment Failure / Q000706:statistics & numerical data*; D005260:Female; D005548:Foreign-Body Migration / Q000453:epidemiology*; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000453:epidemiology*; D011247:Pregnancy; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires
keywords: Cochlear implant; Complications; Head compression bandage; MRI examination; Magnet dislocation