title: Björk-Shiley convexoconcave valves: susceptibility artifacts at brain MR imaging and mechanical valve fractures.
abstract: OBJECTIVE
  To assess the relationship between heart valve history and susceptibility artifacts at magnetic resonance (MR) imaging of the brain in patients with Björk-Shiley convexoconcave (BSCC) valves.
  
  
  METHODS
  MR images of the brain were obtained in 58 patients with prosthetic heart valves: 20 patients had BSCC valve replacements, and 38 had other types of heart valves. Two experienced neuroradiologists determined the presence or absence of susceptibility artifacts in a consensus reading. Artifacts were defined as characteristic black spots that were visible on T2*-weighted gradient-echo MR images. The statuses of the 20 explanted BSCC valves-specifically, whether they were intact or had an outlet strut fracture (OSF) or a single-leg fracture (SLF)-had been determined earlier. Number of artifacts seen at brain MR imaging was correlated with explanted valve status, and differences were analyzed with nonparametric statistical tests.
  
  
  RESULTS
  Significantly more patients with BSCC valves (17 [85%] of 20 patients) than patients with other types of prosthetic valves (18 [47%] of 38 patients) had susceptibility artifacts at MR imaging (P =.005). BSCC valve OSFs were associated with a significantly higher number of artifacts than were intact BSCC valves (P =.01). No significant relationship between SLF and number of artifacts was observed.
  
  
  CONCLUSIONS
  Susceptibility artifacts at brain MR imaging are not restricted to patients with BSCC valves. These artifacts can be seen on images obtained in patients with various other types of fractured and intact prosthetic heart valves.
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Heidelberglaan 100, PO Box 85500, Room D01.335, 3508 GA Utrecht, the Netherlands.
authors.forename: Maarten J
authors.initials: MJ
authors.lastname: van Gorp
authors.forename: Yolanda
authors.initials: Y
authors.lastname: van der Graaf
authors.forename: Bas A J M
authors.initials: BA
authors.lastname: de Mol
authors.forename: Chris J G
authors.initials: CJ
authors.lastname: Bakker
authors.forename: Theo D
authors.initials: TD
authors.lastname: Witkamp
authors.forename: Lino M P
authors.initials: LM
authors.lastname: Ramos
authors.forename: Willem P T M
authors.initials: WP
authors.lastname: Mali
mesh_terms: D000328:Adult; D000368:Aged; D016477:Artifacts; D001921:Brain / Q000473:pathology*; D019544:Equipment Failure Analysis; D005260:Female; D005547:Foreign Bodies / Q000175:diagnosis*; D006350:Heart Valve Prosthesis; D006801:Humans; D020766:Intracranial Embolism / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D011474:Prosthesis Design; D011475:Prosthesis Failure; D018570:Risk Assessment; D013499:Surface Properties