title: Patterns of cerebral perfusion in patients with asymptomatic internal carotid artery disease.
abstract: BACKGROUND
  The perfusion profile of patients with asymptomatic internal carotid artery (ICA) disease has not been well studied. The purpose of this study is to describe the perfusion patterns of patients with asymptomatic ICA disease using computed tomography perfusion (CTP) and its potential value in identifying patients at higher risk for transient ischemic attacks (TIAs) or strokes.
  
  
  METHODS
  We analyzed 32 patients with asymptomatic high grade ICA disease who had CTP and computed tomography angiography (CTA) of the head and neck. Twenty-four patients had severe ICA stenosis and eight had ICA occlusion. The degree of ipsilateral external carotid artery (ECA) and contralateral ICA stenosis, patency of the anterior communicating artery (ACOM), A1 segment and posterior communicating artery (PCOM) were evaluated in all patients.
  
  
  RESULTS
  Sixteen patients had normal CTP and the other 16 patients had cerebral hypoperfusion, characterized by abnormalities in one or more of the three perfusion maps. Ipsilateral hypoplastic A1 segment was more frequent in the group with cerebral hypoperfusion (p = 0.025). Ipsilateral TIAs occurred in two patients, both with cerebral hypoperfusion.
  
  
  CONCLUSIONS
  Cerebral hypoperfusion is present in half of the patients with asymptomatic ICA disease, predominantly in patients with a hypoplastic ipsilateral A1 segment. These patients likely represent a higher-risk group for symptomatic brain ischemia.
authors.affiliation: Department of Neurology, Lahey Clinic, Burlington, MA, USA. claudia.j.chaves@lahey.org
authors.forename: Claudia
authors.initials: C
authors.lastname: Chaves
authors.forename: Kinan
authors.initials: K
authors.lastname: Hreib
authors.forename: Gregory
authors.initials: G
authors.lastname: Allam
authors.forename: Rebecca F
authors.initials: RF
authors.lastname: Liberman
authors.forename: Grace
authors.initials: G
authors.lastname: Lee
authors.forename: Louis R
authors.initials: LR
authors.lastname: Caplan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016893:Carotid Stenosis / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002533:Cerebral Angiography; D002560:Cerebrovascular Circulation; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002546:Ischemic Attack, Transient / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D020521:Stroke / Q000209:etiology; D014057:Tomography, X-Ray Computed