title: Clarifying differences among thrombolysis in cerebral infarction scale variants: is the artery half open or half closed?
abstract: OBJECTIVE
  Although thrombolysis in cerebral infarction (TICI) 2b/3 has been regarded as a successful angiographic outcome, the definition or subclassification of TICI 2 has differed between the original (o-TICI) and modified TICI (m-TICI). We sought to compare interobserver variability for both scores and analyze the subgroups of the TICI 2.
  
  
  METHODS
  Five readers interpreted angiographies independently using a 6-point scale as follows: grade 0, no antegrade flow; grade 1, flow past the initial occlusion without tissue reperfusion; grade 2, partial reperfusion in <50% of the affected territory; grade 3, partial reperfusion in 50% to 66%; grade 4, partial reperfusion in ≥ 67%; grade 5, complete perfusion. Readings using this scale were then converted into o-TICI and m-TICI score. Statistical analysis was performed according to TICI 2 subgroups.
  
  
  RESULTS
  Interobserver agreement was good for the o-TICI and m-TICI scores (intraclass correlation coefficient, 0.73 and 0.67, respectively). Our grade 3 (partial perfusion with 50% to 66%) occupied 19% of total readings, which would have been classified as grade 2a in o-TICI, but as 2b in m-TICI. The m-TICI was more likely to predict good clinical outcome than o-TICI (odds ratio, 2.01 versus 1.63, in reads with TICI 2b/3 versus 0/2a).
  
  
  CONCLUSIONS
  Both TICI scales showed good agreement among readers. However, the variability in partial perfusion thresholds leads to different grading in ≈ 20% of cases and may result in significantly different rates of accurate outcome prediction.
authors: Department of Radiology, Gangnam Severance Hospital, Yonsei University, Seoul, Republic of Korea.
authors: Sang Hyun
authors: SH
authors: Suh
authors: Harry J
authors: HJ
authors: Cloft
authors: Jennifer E
authors: JE
authors: Fugate
authors: Alejandro A
authors: AA
authors: Rabinstein
authors: David S
authors: DS
authors: Liebeskind
authors: David F
authors: DF
authors: Kallmes
mesh_terms: D000368:Aged; D000792:Angiography / Q000379:methods; D001158:Arteries / Q000473:pathology*; D002544:Cerebral Infarction / Q000175:diagnosis* / Q000503:physiopathology*; D005260:Female; D005343:Fibrinolytic Agents / Q000494:pharmacology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009462:Neurology / Q000379:methods; D015588:Observer Variation; D010477:Perfusion; D011871:Radiology / Q000379:methods; D015424:Reperfusion; D015203:Reproducibility of Results; D020521:Stroke / Q000628:therapy; D015912:Thrombolytic Therapy / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D005343:Fibrinolytic Agents