title: Angiographic features, collaterals, and infarct topography of symptomatic occlusive radiation vasculopathy: a case-referent study.
abstract: OBJECTIVE
  Occlusive radiation vasculopathy (ORV) predisposes head-and-neck cancer survivors to ischemic strokes.
  
  
  METHODS
  We analyzed the digital subtraction angiography acquired in 96 patients who had first-ever transient ischemic attack or ischemic strokes attributed to ORV. Another age-matched 115 patients who had no radiotherapy but symptomatic high-grade (>70%) carotid stenoses were enrolled as referent subjects. Digital subtraction angiography was performed within 2 months from stroke onset and delineated carotid and vertebrobasilar circulations from aortic arch up to intracranial branches. Two reviewers blinded to group assignment recorded all vascular lesions, collateral status, and infarct pattern.
  
  
  RESULTS
  ORV patients had less atherosclerotic risk factors at presentation. In referent patients, high-grade stenoses were mostly focal at the proximal internal carotid artery. In contrast, high-grade ORV lesions diffusely involved the common carotid artery and internal carotid artery and were more frequently bilateral (54% versus 22%), tandem (23% versus 10%), associated with complete occlusion in one or both carotid arteries (30% versus 9%), vertebral artery (VA) steno-occlusions (28% versus 16%), and external carotid artery stenosis (19% versus 5%) (all P<0.05). With comparable rates of vascular anomaly, ORV patients showed more established collateral circulations through leptomeningeal arteries, anterior communicating artery, posterior communicating artery, suboccipital/costocervical artery, and retrograde flow in ophthalmic artery. In terms of infarct topography, the frequencies of cortical or subcortical watershed infarcts were similar in both groups.
  
  
  CONCLUSIONS
  ORV angiographic features and corresponding collaterals are distinct from atherosclerotic patterns at initial stroke presentation. Clinical decompensation, despite more extensive collateralization, may precipitate stroke in ORV.
authors.affiliation: Department of Medicine and Therapeutics, Division of Neurology, Prince of Wales Hospital, Shatin, Hong Kong.
authors.forename: Winnie X Y
authors.initials: WX
authors.lastname: Zou
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Leung
authors.forename: Simon C H
authors.initials: SC
authors.lastname: Yu
authors.forename: Edward H C
authors.initials: EH
authors.lastname: Wong
authors.forename: S F
authors.initials: SF
authors.lastname: Leung
authors.forename: Yannie O Y
authors.initials: YO
authors.lastname: Soo
authors.forename: Vincent H L
authors.initials: VH
authors.lastname: Ip
authors.forename: Anne Y Y
authors.initials: AY
authors.lastname: Chan
authors.forename: Wynnie W M
authors.initials: WW
authors.lastname: Lam
authors.forename: Deyond Y W
authors.initials: DY
authors.lastname: Siu
authors.forename: Jill
authors.initials: J
authors.lastname: Abrigo
authors.forename: Kwok Tung
authors.initials: KT
authors.lastname: Lee
authors.forename: David S
authors.initials: DS
authors.lastname: Liebeskind
authors.forename: Ka Sing
authors.initials: KS
authors.lastname: Wong
mesh_terms: D000368:Aged; D015901:Angiography, Digital Subtraction / Q000379:methods; D020520:Brain Infarction / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation / Q000528:radiation effects; D003097:Collateral Circulation / Q000528:radiation effects*; D005260:Female; D006258:Head and Neck Neoplasms / Q000453:epidemiology / Q000532:radiotherapy; D006801:Humans; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011832:Radiation Injuries / Q000000981:diagnostic imaging*; D016037:Single-Blind Method; D020521:Stroke / Q000000981:diagnostic imaging* / Q000453:epidemiology