title: Metallic artifact in MRI after removal of orthopedic implants.
abstract: OBJECTIVE
  The aim of the present study was to evaluate the metallic artifacts in MRI of the orthopedic patients after removal of metallic implants.
  
  
  METHODS
  From March to August 2009, 40 orthopedic patients operated for removal of orthopedic metallic implants were studied by post-operative MRI from the site of removal of implants. A grading scale of 0-3 was assigned for artifact in MR images whereby 0 was considered no artifact; and I-III were considered mild, moderate, and severe metallic artifacts, respectively. These grading records were correlated with other variables including the type, size, number, and composition of metallic devices; and the site and duration of orthopedic devices stay in the body.
  
  
  RESULTS
  Metallic susceptibly artifacts were detected in MRI of 18 of 40 cases (45%). Screws and pins in removed hardware were the most important factors for causing artifacts in MRI. The artifacts were found more frequently in the patients who had more screws and pins in the removed implants. Gender, age, site of implantation of the device, length of the hardware, composition of the metallic implants (stainless steel versus titanium), and duration of implantation of the hardware exerted no effect in producing metallic artifacts after removal of implants. Short TE sequences of MRI (such as T1 weighted) showed fewer artifacts.
  
  
  CONCLUSIONS
  Susceptibility of metallic artifacts is a frequent phenomenon in MRI of patients upon removal of metallic orthopedic implants.
authors.affiliation: Department of Radiology, and Medical Imaging Research Center, Namazi Hospital, Namazi Square, Shiraz, Iran. bagherih@sums.ac.ir
authors.forename: Mohammad Hadi
authors.initials: MH
authors.lastname: Bagheri
authors.forename: Mehrdad Mohammad
authors.initials: MM
authors.lastname: Hosseini
authors.forename: Mohammad Jafar
authors.initials: MJ
authors.lastname: Emami
authors.forename: Amin Aiboulhassani
authors.initials: AA
authors.lastname: Foroughi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016477:Artifacts; D002648:Child; D020878:Device Removal; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008670:Metals; D008875:Middle Aged; D009984:Orthopedic Fixation Devices; D011446:Prospective Studies; D018709:Statistics, Nonparametric
chemical_list: D008670:Metals