title: What is meant by "TICI"?
abstract: BACKGROUND
  In 2003, Higashida et al proposed the Thrombolysis In Cerebral Infarction scale to evaluate angiographic intracranial flow. Our aim is to review how subsequently published studies define TICI.
  
  
  METHODS
  We used the ISI Web of Knowledge and SciVerse Scopus databases to search for "TICI" and "thrombolysis in cerebral infarction" and for articles that cited the original TICI paper from January 2004 through May 2012. Articles were categorized according to their definition of the TICI categories, typically grades 0-4, with grade 2 (partial reperfusion) subdivided into 2a and 2b, and rate of contrast entry to the perfused area. In addition, we catalogued the type of redefinitions of TICI subcategory 2 and additions of new categories.
  
  
  RESULTS
  Of 236 articles screened, 74 were included. Eight (11%) explicitly followed the TICI scale as originally defined. Thirty-seven (50%) cited Higashida but did not define their scale. Fifteen (21%) used and explained modified scales. Thirteen (18%) used the term TICI, but did not define the scale and did not cite Higashida. Eighteen (24%) specified a 2a subcategory. Nine defined grade 2a as <67% filling, 6 defined it as <50%, and 3 did not offer a percentage. Two studies added a 2c subcategory. Fifty-two (70%) used a cutoff level to define "successful reperfusion." Of these, 65% used TICI ≥2, 33% used TICI ≥2b, and 2% used TICI = 3.
  
  
  CONCLUSIONS
  There is substantial variability in the definition and/or application of the TICI scale in the literature. This variability could considerably impact our understanding of results of revascularization studies.
authors.affiliation: Division of Critical Care Neurology.
authors.forename: J E
authors.initials: JE
authors.lastname: Fugate
authors.forename: A M
authors.initials: AM
authors.lastname: Klunder
authors.forename: D F
authors.initials: DF
authors.lastname: Kallmes
mesh_terms: D002548:Cerebral Revascularization / Q000145:classification* / Q000706:statistics & numerical data*; D017063:Outcome Assessment, Health Care / Q000379:methods / Q000706:statistics & numerical data*; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D012720:Severity of Illness Index; D009626:Terminology as Topic; D015912:Thrombolytic Therapy / Q000145:classification* / Q000706:statistics & numerical data*; D018875:Vocabulary, Controlled