title: Comparison of four different collateral scores in acute ischemic stroke by CT angiography.
abstract: OBJECTIVE
  Multiple scores have been described for the assessment of collateralization in acute ischemic stroke. Currently, there is no gold standard for collateral assessment by CT angiography (CTA). This study compared four frequently used collateral scores with regard to their correlation with early infarct core and mismatch ratio.
  
  
  METHODS
  30 consecutive patients with acute occlusion of the M1 segment or terminal carotid artery were reviewed retrospectively. Collaterals were assessed using dynamic and also single-phase CTA according to grading systems by the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR), Alberta Stroke Program Early CT Score (ASPECTS) (on collaterals), Christoforidis et al and Miteff et al. The Christoforidis and ASITN/SIR scores, which were initially designed for conventional angiography, were adapted to be applicable to CTA. The scores were compared with respect to early infarct core and mismatch ratio in perfusion CT estimated by RAPID software using Spearman correlation.
  
  
  RESULTS
  ASITN/SIR and ASPECTS collateral scores showed good correlation with early infarct core (rho=-0.696, p<0.001 and rho=-0.677, p<0.001) and mismatch ratio (rho=0.609, p<0.001 and rho=0.581, p<0.001). In contrast, the Christoforidis and Miteff scores correlated less well with infarct core (rho=0.245, p=0.191 and rho=-0.272, p=0.145, respectively) and mismatch ratio (rho=-0.329, p=0.075 and rho=0.279, p=0.135, respectively). ASPECTS and ASITN/SIR showed excellent cross-correlation (rho=0.901, p<0.001).
  
  
  CONCLUSIONS
  Compared with the Christoforidis and Miteff scores, the modified ASITN/SIR and ASPECTS collateral scores showed consistently higher correlation with the extent of early infarct core and mismatch volume. This is probably because these scores evaluate the extent and delay of vascular enhancement in the affected territory rather than the backflow of contrast medium to the occlusion.
authors.affiliation: Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Fatih
authors.initials: F
authors.lastname: Seker
authors.affiliation: Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Arne
authors.initials: A
authors.lastname: Potreck
authors.affiliation: Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Möhlenbruch
authors.affiliation: Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Bendszus
authors.affiliation: Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Mirko
authors.initials: M
authors.lastname: Pham
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000628:therapy; D002533:Cerebral Angiography / Q000379:methods / Q000592:standards*; D003097:Collateral Circulation; D000072226:Computed Tomography Angiography / Q000379:methods / Q000592:standards*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012720:Severity of Illness Index; D020521:Stroke / Q000000981:diagnostic imaging* / Q000628:therapy
keywords: CT Angiography; CT perfusion; Stroke