title: MRI acoustic noise can harm experimental and companion animals.
abstract: OBJECTIVE
  To assess possible damage to the hearing of experimental and companion animal subjects of magnetic resonance imaging (MRI) scans.
  
  
  METHODS
  Using animal hearing threshold data and sound level measurements from typical MRI pulse sequences, we estimated "equivalent loudness" experienced by several experimental and companion animals commonly subjects of MRI scans. We compared the equivalent loudness and exam duration to safe noise standards set by the National Institute for Occupational Safety and Health (NIOSH).
  
  
  RESULTS
  Monkeys, dogs, cats, pigs, and rabbits are frequently exposed to equivalent loudness levels during MRI scans beyond what is considered safe for human exposure. The sensitive frequency ranges for rats and mice are shifted substantially upward and their equivalent loudness levels fall within the NIOSH safe zone.
  
  
  CONCLUSIONS
  MRI exposes many animals to levels of noise and duration that would exceed NIOSH human exposure limits. Researchers and veterinarians should use hearing protection for animals during MRI scans. Experimental research animals used in MRI studies are frequently kept and reimaged, and hearing loss could result in changed behavior. Damage to companion animals' hearing could make them less sensitive to commands and generally worsen interactions with family members. Much quieter MRI scanners would help decrease stress and potential harm to scanned animals, normalize physiology during MRI, and enable MRI of awake animals.
authors.affiliation: Otolaryngology-HNS, Johns Hopkins School of Medicine, 600 North Wolfe St., Baltimore, MD 21287, USA.
authors.forename: Amanda M
authors.initials: AM
authors.lastname: Lauer
authors.forename: AbdEl-Monem M
authors.initials: AM
authors.lastname: El-Sharkawy
authors.forename: Dara L
authors.initials: DL
authors.lastname: Kraitchman
authors.forename: William A
authors.initials: WA
authors.lastname: Edelstein
mesh_terms: D000818:Animals; D002415:Cats; D004285:Dogs; D004781:Environmental Exposure / Q000009:adverse effects* / Q000032:analysis*; D006317:Hearing Loss, Noise-Induced / Q000517:prevention & control*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000009:adverse effects*; D051379:Mice; D009622:Noise / Q000009:adverse effects* / Q000517:prevention & control*; D057805:Pets; D011817:Rabbits; D051381:Rats; D013018:Sound Spectrography / Q000379:methods*