title: Frequency of referral of patients with safety-related contraindications to magnetic resonance imaging.
abstract: OBJECTIVE
  To analyse the frequency of patients with absolute and relative contraindications to magnetic resonance (MR) imaging who were actually referred to an outpatient imaging centre for an MR examination
  
  
  METHODS
  Altogether a total of 51,547 consecutive patients were included between November 1997 and December 2005. Reasons preventing MR imaging were classified into the following categories: absolute and relative contraindications.
  
  
  RESULTS
  The referral frequency of patients with absolute contraindications to MR imaging was 0.41% (211 of 51,547 patients; 95% CI, 0.36-0.47%). The absolute contraindications were shrapnels located in biologically sensitive areas (121 patients, 0.23%; 95% CI, 0.20-0.28%), cardiac pacemakers (42 patients, 0.08%; 95% CI, 0.06-0.11%), and other unsafe implants (48 patients, 0.09%; 95% CI, 0.07-0.12%). Also patients with a relative contraindication to MR imaging were referred such as women with a first-trimester pregnancy (13 patients, 0.03%; 95% CI, 0.01-0.04%).
  
  
  CONCLUSIONS
  Surprisingly, a considerable number of patients (0.41%) with cardiac pacemakers, other metallic implants (not approved for MR), or shrapnels are referred to MR facilities despite the well-known recommendations not to examine such patients. Thus, absolute contraindications to MR imaging are commonly found among patients referred for MR examinations and every effort needs to be made to screen patients prior to MR imaging for such contraindications to avoid detrimental results. Also, institutions placing implants (approved and unapproved for MR) should become legally responsible for providing the required information to the patients and their physicians.
authors: Department of Radiology, Charité, Medical School, Humboldt-Universität zu Berlin, Germany. marc.dewey@charite.de
authors: Marc
authors: M
authors: Dewey
authors: Tania
authors: T
authors: Schink
authors: Charles F
authors: CF
authors: Dewey
mesh_terms: D000554:Ambulatory Care Facilities; D015331:Cohort Studies; D000075202:Contraindications; D005260:Female; D005547:Foreign Bodies / Q000150:complications; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008485:Medical Audit; D008670:Metals; D008875:Middle Aged; D010138:Pacemaker, Artificial; D011247:Pregnancy; D019736:Prostheses and Implants; D012017:Referral and Consultation / Q000592:standards / Q000706:statistics & numerical data*
chemical_list: D008670:Metals