title: Artefacts at a glance: differentiating features of artefactual stenosis from true stenosis at the genu of the petrous internal carotid artery on TOF MRA.
abstract: OBJECTIVE
  To investigate the distinguishing features of artefactual stenosis from true stenosis at the genu of the petrous internal carotid artery (ICA) on time of flight (TOF) magnetic resonance angiography (MRA).
  
  
  METHODS
  Both TOF MRA and digital subtraction angiography (DSA) were performed in 65 patients with 74 vessels who demonstrated artefactual stenosis in 43 patients with 50 vessels and true stenosis in 22 patients with 24 vessels. The following findings of the signal loss were compared between the two groups: (1) margin, (2) darkness, (3) the presence of bilaterality, (4) the presence of tandem arterial stenosis, (5) the location of the epicentre, and (6) length.
  
  
  RESULTS
  In five out of the six evaluated items, statistically significant differences were present between the two groups (p<0.00 in all five items). Artefactual stenosis more frequently showed signal loss with ill-defined margins (47/50), less darkness compared to the background darkness (46/50), the absence of tandem arterial stenosis (35/50), epicentre at the genu (34/50), and shorter length (2.57 ± 0.68 mm). No significant difference was noted in the presence of bilaterality of signal loss between the two groups (p=0.706).
  
  
  CONCLUSIONS
  Several MRA features can be useful for suggesting artefactual stenosis rather than true stenosis at the genu of the petrous ICA on TOF MRA.
authors.affiliation: Department of Radiology, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, South Korea.
authors.forename: S K
authors.initials: SK
authors.lastname: Lee
authors.affiliation: Department of Radiology, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, South Korea. Electronic address: ahn-kj@catholic.ac.kr.
authors.forename: K J
authors.initials: KJ
authors.lastname: Ahn
authors.affiliation: Department of Radiology, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, South Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Jang
authors.affiliation: Department of Radiology, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, South Korea.
authors.forename: H S
authors.initials: HS
authors.lastname: Choi
authors.affiliation: Department of Radiology, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, South Korea.
authors.forename: S L
authors.initials: SL
authors.lastname: Jung
authors.affiliation: Department of Radiology, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, South Korea.
authors.forename: B S
authors.initials: BS
authors.lastname: Kim
mesh_terms: D000368:Aged; D015901:Angiography, Digital Subtraction; D016477:Artifacts; D002343:Carotid Artery, Internal / Q000473:pathology*; D003251:Constriction, Pathologic; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014283:Triiodobenzoic Acids
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; C044834:iodixanol