title: Three-dimensional contrast-enhanced magnetic resonance angiography of carotid artery after stenting.
abstract: OBJECTIVE
  This study presents 3-dimensional, contrast-enhanced, magnetic resonance (MR) angiographic appearances of the carotid artery after stenting.
  
  
  METHODS
  The authors reviewed contrast-enhanced MR angiograms of 18 carotid arteries in 13 patients. These arteries were not stenotic or occluded in the stented segment, as shown on carotid angio-grams (11 patients) or carotid Doppler images (2 patients) obtained later.
  
  
  RESULTS
  Five patients had 1 stent in each of their bilateral carotid arteries. One patient with 1 stent in 1 artery underwent the examination twice with different MR coils. Different artifact patterns were found in 19 carotid-stent examinations. Type 1a involved short segments of false narrowing or false focal occlusion at both ends of the stent (n = 12); the carotid artery in the stented segment between the ends was normal. Types 2a and 2b occurred along the stented segment of the artery between the 2 ends of the stent. Type 2a was milder, with segmental faint signal intensity or luminal stenosis in the entire length of the stented segment (n = 5). Type 2b was total loss of luminal signal intensity over the whole length of the stented segment (n = 2). Last, type 1b was a band of hyperintensity at the ends of type 2a or 2b artifacts. Types 1a and 1b were due to susceptibility effect, and types 2a and 2b were from radio-frequency shielding effect. Both of these effects were identified in MR angiogram of nitinol stents and stainless steel stents.
  
  
  CONCLUSIONS
  Awareness of these artifacts is essential to prevent misdiagnosis.
authors.affiliation: Department of Radiology, Veterans General Hospital-Taipei and School of Medicine, National Yang Ming University, Taipei, 11217, Taiwan. mhteng@vghtpe.gov.tw
authors.forename: Michael M H
authors.initials: MM
authors.lastname: Teng
authors.forename: Fong
authors.initials: F
authors.lastname: Tsai
authors.forename: Adrian Jy-Kang
authors.initials: AJ
authors.lastname: Liou
authors.forename: Jiing-Feng
authors.initials: JF
authors.lastname: Lirng
authors.forename: Feng-Chi
authors.initials: FC
authors.lastname: Chang
authors.forename: Chao-Bao
authors.initials: CB
authors.lastname: Luo
authors.forename: Hui-Cheng
authors.initials: HC
authors.lastname: Cheng
mesh_terms: D000368:Aged; D016477:Artifacts; D016893:Carotid Stenosis / Q000175:diagnosis* / Q000601:surgery; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography; D008297:Male; D015607:Stents
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA