title: Internal cerebral vein asymmetry on follow-up brain computed tomography after intravenous thrombolysis in acute anterior circulation ischemic stroke is associated with poor outcome.
abstract: BACKGROUND
  Identifying early predictors of functional outcome after acute ischemic stroke (AIS) is important for planning rehabilitation strategies. Internal cerebral veins (ICV) drain deep parts of brain, run parallel to each other, and consistently seen on computed tomography angiography (CTA). Even minor asymmetry in their filling can be identified. We hypothesized that venous drainage would be impaired in patients with acute occlusion of internal carotid artery or middle cerebral artery. Because systemic thrombolysis can alter the vascular findings, we evaluated the relationship between ICV asymmetry on follow-up CTA and functional outcome.
  
  
  METHODS
  Consecutive AIS patients treated with intravenous thrombolysis between 2007 and 2010 were included. ICV asymmetry was assessed by 2 independent blinded stroke neurologists/neuroradiologists. Functional outcome was assessed by the modified Rankin Scale (mRS) at 3 months, dichotomized as good (0-1) and poor (2-6). Data were analyzed for predictors of functional outcome.
  
  
  RESULTS
  Of 2238 patients with AIS, 226 (10.1%) anterior circulation AIS patients received intravenous thrombolysis. The median age was 65 years (range 19-92), 44% were men, and median National Institutes of Health Stroke Scale (NIHSS) score was 16 points (range 4-32). Hypertension was the commonest risk factor in 173 (76.5%) patients, whereas 78 (34.5%) had atrial fibrillation. ICV asymmetry on follow-up CTA was assessed in 103 (45.5%) patients. Admission NIHSS score (odds ratio [OR] 1.07; 95% confidence interval [CI] 1.079-1.201, P = .046), change in NIHSS score during first 24 hours (OR .737; 95% CI .672-.807, P < .0001), and ICV asymmetry on follow-up CTA (OR 20.3; 95% CI 4.67-52.07, P < .0001) independently predicted poor outcome at 3 months.
  
  
  CONCLUSIONS
  ICV asymmetry on follow-up CTA after intravenous thrombolysis is an early predictor of poor functional outcome.
authors.affiliation: Division of Neurology, Department of Medicine, National University Health System, Singapore; Yong Loo Lin School of Medicine, National University of Singapore, Singapore. Electronic address: drvijay@singnet.com.sg.
authors.forename: Vijay K
authors.initials: VK
authors.lastname: Sharma
authors.affiliation: Division of Neurology, Department of Medicine, National University Health System, Singapore.
authors.forename: Leonard L L
authors.initials: LL
authors.lastname: Yeo
authors.affiliation: Division of Neurology, Department of Medicine, National University Health System, Singapore.
authors.forename: Hock L
authors.initials: HL
authors.lastname: Teoh
authors.affiliation: Biostatistics Unit, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Liang
authors.initials: L
authors.lastname: Shen
authors.affiliation: Division of Neurology, Department of Medicine, National University Health System, Singapore.
authors.forename: Bernard P L
authors.initials: BP
authors.lastname: Chan
authors.affiliation: Division of Neurology, Department of Medicine, National University Health System, Singapore.
authors.forename: Raymond C
authors.initials: RC
authors.lastname: Seet
authors.affiliation: Division of Neurology, Department of Medicine, National University Health System, Singapore.
authors.forename: Aftab
authors.initials: A
authors.lastname: Ahmad
authors.affiliation: Department of Diagnostic Imaging, National University Health System, Singapore.
authors.forename: Vincent F
authors.initials: VF
authors.lastname: Chong
authors.affiliation: Division of Neurology, Department of Medicine, National University Health System, Singapore.
authors.forename: Prakash R
authors.initials: PR
authors.lastname: Paliwal
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging*; D002545:Brain Ischemia / Q000145:classification / Q000000981:diagnostic imaging*; D002550:Cerebral Veins / Q000000981:diagnostic imaging* / Q000473:pathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D020521:Stroke / Q000145:classification / Q000000981:diagnostic imaging*; D015912:Thrombolytic Therapy; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator
keywords: Acute ischemic stroke; CT angiography; internal cerebral vein; thrombolysis