title: Clot burden score on admission T2*-MRI predicts recanalization in acute stroke.
abstract: OBJECTIVE
  To propose a T2*-MR adaptation of the computed tomography angiography-clot burden score (CBS), and assess its value as predictor of 24-hour recanalization and clinical outcome in anterior circulation stroke treated by intravenous thrombolysis ≤4.5 hours from onset.
  
  
  METHODS
  Two independent observers retrospectively analyzed pretreatment T2* images for evaluation of clot burden, using a 10-point scale T2*-CBS. Three points are subtracted for susceptibility vessel sign in the supraclinoid internal carotid artery, 2 points each for susceptibility vessel sign in the proximal and distal part of middle cerebral artery, and 1 point each for susceptibility vessel sign in middle cerebral artery branches (with a maximum of 2 points) and for susceptibility vessel sign in anterior cerebral artery. Associations with 24-hour recanalization and favorable outcome (3-month modified Rankin Scale score, ≤2) were assessed in multivariate analyses.
  
  
  RESULTS
  We analyzed 184 consecutive patients (mean age, 67 years) with median (interquartile range) admission National Institutes of Health Stroke Scale score and onset-to-treatment time of 15 (9-19) and 151 (120-185) minutes, respectively. The intraclass correlation for T2*-CBS between observers was 0.97 (95% confidence interval, 0.97-0.98). In multivariate analyses, T2*-CBS >6 was significantly associated with 24-hour recanalization (adjusted odds ratio, 5.1 [1.9-13.5]; P=0.001) or with favorable outcome (adjusted odds ratio, 4.2 [1.7-10.8]; P=0.003).
  
  
  CONCLUSIONS
  T2*-CBS, a new reproducible semiquantitative score adapted from the computed tomography angiography-CBS, is associated with 24-hour recanalization and 3-month outcome after intravenous thrombolysis. This score needs external validation and could be useful to identify poor responders to intravenous thrombolysis.
authors.affiliation: Department of Radiology, Centre Hospitalier Sainte-Anne, Université Paris Descartes Sorbonne Paris Cité, Centre de Psychiatrie et Neurosciences, INSERM S894, Paris, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Legrand
authors.forename: Olivier
authors.initials: O
authors.lastname: Naggara
authors.forename: Guillaume
authors.initials: G
authors.lastname: Turc
authors.forename: Charles
authors.initials: C
authors.lastname: Mellerio
authors.forename: Pauline
authors.initials: P
authors.lastname: Roca
authors.forename: David
authors.initials: D
authors.lastname: Calvet
authors.forename: Marc-Antoine
authors.initials: MA
authors.lastname: Labeyrie
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Baron
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Mas
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Meder
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Touzé
authors.forename: Catherine
authors.initials: C
authors.lastname: Oppenheim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002536:Cerebral Arteries / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D020521:Stroke / Q000188:drug therapy* / Q000473:pathology; D015912:Thrombolytic Therapy / Q000379:methods*; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage / Q000627:therapeutic use*; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome
chemical_list: D010959:Tissue Plasminogen Activator
keywords: MRI; infarction; outcome; thrombolysis; thrombus