title: Arterial Spin-Labeling Magnetic Resonance Perfusion Imaging with Dual Postlabeling Delay in Internal Carotid Artery Steno-occlusion: Validation with Digital Subtraction Angiography.
abstract: BACKGROUND
  Arterial spin-labeling magnetic resonance perfusion imaging (ASL-MRI) allows noninvasive measurement of cerebral blood flow (CBF) but depends on the arterial transit time (ATT). With the commonly used single postlabeling delay (PLD) of 1.5 seconds, slow flow through collateral vessels may be underestimated. We used both 1.5 and 2.5 seconds to overcome this problem. We validated these PLD settings by measuring the ATT and identifying the angiographic circulation using digital subtraction angiography (DSA).
  
  
  METHODS
  We retrospectively selected 5 patients with unilateral occlusion or stenosis of the internal carotid artery (ICA) in whom ASL-MRI showed low CBF with 1.5-second PLD in the target area and improved CBF with 2.5-second PLD. We then compared the ASL-MRI findings visually with DSA findings at 1.5 and 2.5 seconds after injection of the contrast. When arterial transit artifacts (ATAs), attributed to stagnant intravascular spin-labeled blood, were observed, DSA findings were analyzed visually at 4.5 seconds.
  
  
  RESULTS
  DSA revealed that the hypovascular area seen at 1.5 seconds was improved via the primary and secondary collaterals and delayed anterograde flow at 2.5 seconds. Serpiginous or round-shaped ATAs, which appeared in nearly the same configuration on dual PLD ASL-MRI, were attributed to stagnant collaterals and flow in the M2 portion of the middle cerebral artery and ICA during the late venous phase.
  
  
  CONCLUSIONS
  Use of dual PLD times was validated by the DSA findings. ATA detection using the dual PLDs also differentiated well-developed and stagnant collateral vessels from focal hyperperfusion.
authors.affiliation: Department of Neurosurgery, Kyushu Rosai Hospital, Kitakyushu, Japan; Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Akiyama
authors.affiliation: Department of Neurosurgery, Kyushu Rosai Hospital, Kitakyushu, Japan; Department of Neurosurgery, Fukuoka Children's Hospital, Fukuoka, Japan.
authors.forename: Takato
authors.initials: T
authors.lastname: Morioka
authors.affiliation: Department of Neurosurgery, Kyushu Rosai Hospital, Kitakyushu, Japan; Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Department of Neurosurgery, Fukuoka Children's Hospital, Fukuoka, Japan. Electronic address: shimogawa28@gmail.com.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Shimogawa
authors.affiliation: Department of Neurosurgery, Kyushu Rosai Hospital, Kitakyushu, Japan.
authors.forename: Sei
authors.initials: S
authors.lastname: Haga
authors.affiliation: Department of Neurosurgery, Kyushu Rosai Hospital, Kitakyushu, Japan; Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Sayama
authors.affiliation: Department of Cerebrovascular Disease, Kyushu Rosai Hospital, Kitakyushu, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kanazawa
authors.affiliation: Department of Cerebrovascular Disease, Kyushu Rosai Hospital, Kitakyushu, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Murao
authors.affiliation: Department of Cerebrovascular Disease, Kyushu Rosai Hospital, Kitakyushu, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Arakawa
mesh_terms: D000368:Aged; D015901:Angiography, Digital Subtraction / Q000379:methods*; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging*; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D055420:Perfusion Imaging / Q000379:methods*; D012189:Retrospective Studies; D013113:Spin Labels
chemical_list: D013113:Spin Labels
keywords: Arterial spin labeling; digital subtraction angiography; perfusion image; postlabeling delay