Document Detail


Magnetic properties of middle ear and stapes implants in a 9.4-T magnetic resonance field.
MedLine Citation:
PMID:  16988620     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
HYPOTHESIS: A 9.4-T magnetic resonance (MR) field may cause motion displacement of the middle ear and stapes implants not previously observed with 1.5- and 3.0-T magnets. BACKGROUND: Publications have described the safety limitations of some otologic implants in 4.7-T field and resulted in several companywide patient safety-related recalls. To date, no studies have been reported for otologic implants in a 9.4-T MR field nor have comparisons been made with 4.7-T field strengths. METHODS: Twenty-three commonly used middle ear and stapes prostheses were selected and exposed to 9.4-T MR fields in vitro within petri dishes, and eight of the 23 implants were further studied ex corpus in human temporal bones (TBs) in a 9.4-T MR field. This study has been approved by the institutional review board. RESULTS: Eight prostheses in petri dishes grossly displaced at 9.4 T, three of which had not previously moved in either the 1.5- or 3.0-T magnets. The eight TB preparations showed no avulsions or motion indicators after exposure at 9.4 T. CONCLUSION: Middle ear and stapes implants can move dramatically in petri dishes at 9.4-T MR field, more so than at 1.5 and 3.0 T. The absence of avulsions in the TB group strongly suggests that the surgical means used to fixate the middle ear implants to the middle ear structures successfully overcomes the magnetic moment produced at MR field strengths up to 9.4 T. The use of MR imaging is not contraindicated by this study's findings.
Authors:
Michael H Fritsch; Jason J Gutt; Ilka C Naumann
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology     Volume:  27     ISSN:  1531-7129     ISO Abbreviation:  Otol. Neurotol.     Publication Date:  2006 Dec 
Date Detail:
Created Date:  2006-11-28     Completed Date:  2008-05-13     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100961504     Medline TA:  Otol Neurotol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1064-9     Citation Subset:  IM    
Affiliation:
Department of Otolaryngology-Head and Neck Surgery, Indiana University Medical Center, Indianapolis, Indiana 46202, USA. mfritsch@iupui.edu
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MeSH Terms
Descriptor/Qualifier:
Cadaver
Equipment Failure Analysis
Ferric Compounds / adverse effects*
Humans
Magnetic Resonance Imaging / adverse effects*
Ossicular Prosthesis*
Ossicular Replacement / methods
Vibration / adverse effects
Chemical
Reg. No./Substance:
0/Ferric Compounds; 1317-54-0/ferrite

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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