title: Prevalence of intracranial stenosis in a Norwegian ischemic stroke population.
abstract: BACKGROUND
  There is no data about prevalence of intracranial stenosis (IS) in Northern Europe. This study aimed to investigate the prevalence of symptomatic and asymptomatic IS in a Norwegian, community-based ischemic stroke population.
  
  
  METHODS
  In a prospective study, all ischemic stroke or transient ischemic attack (TIA) patients were screened for IS by transcranial color-coded sonography, magnetic resonance angiography, and/or computed tomography angiography. Patients with IS and any cardiac arrhythmia or other possible causes of IS than atherosclerosis were excluded. IS was defined as symptomatic if the infarct/symptoms were related to the territory of the stenotic artery. Risk factors for cerebrovascular disease were registered on admission.
  
  
  RESULTS
  During an 18-month study period, 607 patients had an ischemic stroke or a TIA. Out of 69 patients with IS (11.4%), 7 patients were excluded because having atrial fibrillation, and IS of possible atherosclerotic etiology was therefore diagnosed in 62 patients (10.2%). IS was symptomatic in 45 patients (7.4%). Diabetes mellitus was the only risk factor significantly associated with symptomatic IS (odds ratio 2.39, 95% confidence interval [CI] 1.03-5.54, P=.04).
  
  
  CONCLUSIONS
  IS occurs in approximately 10% and is symptomatic in about 7% of a Norwegian ischemic stroke/TIA population. Diabetes mellitus appears to be the major risk factor for IS.
authors.affiliation: Center for Neurovascular Diseases, Haukeland University Hospital, Bergen, Norway. Electronic address: nicola.logallo@gmail.com.
authors.forename: Nicola
authors.initials: N
authors.lastname: Logallo
authors.affiliation: Centre for Age-related Medicine, Stavanger University Hospital, Stavanger, Norway.
authors.forename: Halvor
authors.initials: H
authors.lastname: Naess
authors.affiliation: Center for Neurovascular Diseases, Haukeland University Hospital, Bergen, Norway.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Waje-Andreassen
authors.affiliation: Department of Clinical Medicine, University of Bergen, Bergen, Norway.
authors.forename: Lars
authors.initials: L
authors.lastname: Thomassen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000473:pathology; D002545:Brain Ischemia / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D003251:Constriction, Pathologic / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D006801:Humans; D002537:Intracranial Arteriosclerosis / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D015995:Prevalence; D020521:Stroke / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology
keywords: Atherosclerosis; epidemiology; intracranial atherosclerosis; intracranial stenosis; ischemic stroke; transcranial color-coded sonography