title: Intra-arterial high signals on arterial spin labeling perfusion images predict the occluded internal carotid artery segment.
abstract: OBJECTIVE
  Arterial spin labeling (ASL) involves perfusion imaging using the inverted magnetization of arterial water. If the arterial arrival times are longer than the post-labeling delay, labeled spins are visible on ASL images as bright, high intra-arterial signals (IASs); such signals were found within occluded vessels of patients with acute ischemic stroke. The identification of the occluded segment in the internal carotid artery (ICA) is crucial for endovascular treatment. We tested our hypothesis that high IASs on ASL images can predict the occluded segment.
  
  
  METHODS
  Our study included 13 patients with acute ICA occlusion who had undergone angiographic and ASL studies within 48 h of onset. We retrospectively identified the high IAS on ASL images and angiograms and recorded the occluded segment and the number of high IAS-positive slices on ASL images. The ICA segments were classified as cervical (C1), petrous (C2), cavernous (C3), and supraclinoid (C4).
  
  
  RESULTS
  Of seven patients with intracranial ICA occlusion, five demonstrated high IASs at C1-C2, suggesting that high IASs could identify stagnant flow proximal to the occluded segment. Among six patients with extracranial ICA occlusion, five presented with high IASs at C3-C4, suggesting that signals could identify the collateral flow via the ophthalmic artery. None had high IASs at C1-C2. The mean number of high IAS-positive slices was significantly higher in patients with intra- than extracranial ICA occlusion.
  
  
  CONCLUSIONS
  High IASs on ASL images can identify slow stagnant and collateral flow through the ophthalmic artery in patients with acute ICA occlusion and help to predict the occlusion site.
authors.affiliation: Department of Neurosurgery, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Shu
authors.initials: S
authors.lastname: Sogabe
authors.affiliation: Department of Neurosurgery, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan. junichirosatomi@gmail.com.
authors.forename: Junichiro
authors.initials: J
authors.lastname: Satomi
authors.affiliation: Department of Neurosurgery, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Tada
authors.affiliation: Department of Neurosurgery, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Kanematsu
authors.affiliation: Department of Neurosurgery, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Kuwayama
authors.affiliation: Department of Neurosurgery, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Yagi
authors.affiliation: Department of Neurosurgery, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Shotaro
authors.initials: S
authors.lastname: Yoshioka
authors.affiliation: Department of Neurosurgery, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Mizobuchi
authors.affiliation: Department of Neurosurgery, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Mure
authors.affiliation: Department of Neurosurgery, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Izumi
authors.initials: I
authors.lastname: Yamaguchi
authors.affiliation: Department of Radiology, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Abe
authors.affiliation: Department of Clinical Neurosciences, Institute of Biomedical Biosciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Yamamoto
authors.affiliation: Department of Neurosurgery, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Keiko T
authors.initials: KT
authors.lastname: Kitazato
authors.affiliation: Department of Clinical Neurosciences, Institute of Biomedical Biosciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Ryuji
authors.initials: R
authors.lastname: Kaji
authors.affiliation: Department of Radiology, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Harada
authors.affiliation: Department of Neurosurgery, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Nagahiro
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D002533:Cerebral Angiography; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013113:Spin Labels
chemical_list: D013113:Spin Labels
keywords: Arterial spin labeling; Internal carotid artery occlusion; Magnetic resonance imaging; Occluded segment