title: Artificial luminal narrowing on contrast-enhanced magnetic resonance angiograms on an occasion of stent-assisted coiling of intracranial aneurysm: in vitro comparison using two different stents with variable imaging parameters.
abstract: OBJECTIVE
  Intracranial stenting for stent-assisted coiling of aneurysms requires adequate follow-up imaging. The aim of this in vitro study was to compare in-stent artificial luminal narrowing on contrast-enhanced MR angiograms (CE-MRA) when applying Neuroform® and Enterprise® stents for stent-assisted coiling.
  
  
  METHODS
  Two intracranial nitinol stents (Enterprise® and Neuroform®) were placed in silicon tubes and then imaged at 3 T and 1.5 T by the use of a T1-weighted three-dimensional spoiled gradient-echo sequence with minimal TR and TE. CE-MRAs were obtained by using different imaging planes, voxel sizes, and bandwidths, and with or without parallel imaging. Artificial lumen narrowing (ALN) was calculated and the results were compared.
  
  
  RESULTS
  Lower magnetic field strength, axial plane perpendicular to axis of stent, and wider bandwidth resulted in a lower ALN on CE-MRA for both stents. Larger voxel size resulted in lower ALN for Neuroform® stent. The parallel imaging acceleration factor did not affect ALN. The mean ALN was lower for Neuroform®, but it was not significant by a paired t test.
  
  
  CONCLUSIONS
  CE-MRA of the stented lumen of vascular phantom was partially impaired with ALN. Consequently, image plane orientation, magnetic field strength, bandwidth, and voxel size should be adjusted appropriately to reduce ALN.
authors.affiliation: Department of Radiology, Seoul St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul 137-701, Korea.
authors.forename: Jee Hyun
authors.initials: JH
authors.lastname: Seok
authors.forename: Hyun Seok
authors.initials: HS
authors.lastname: Choi
authors.forename: So-Lyung
authors.initials: SL
authors.lastname: Jung
authors.forename: Kook-Jin
authors.initials: KJ
authors.lastname: Ahn
authors.forename: Myeong Jin
authors.initials: MJ
authors.lastname: Kim
authors.forename: Yong Sam
authors.initials: YS
authors.lastname: Shin
authors.forename: Bum-soo
authors.initials: BS
authors.lastname: Kim
mesh_terms: D000497:Alloys; D002533:Cerebral Angiography; D003287:Contrast Media; D006801:Humans; D021621:Imaging, Three-Dimensional; D066298:In Vitro Techniques; D002532:Intracranial Aneurysm / Q000473:pathology* / Q000628:therapy*; D016014:Linear Models; D018810:Magnetic Resonance Angiography / Q000379:methods*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D015607:Stents
chemical_list: D000497:Alloys; D003287:Contrast Media; C013616:nitinol