title: Comparison of CTA- and DSA-Based Collateral Flow Assessment in Patients with Anterior Circulation Stroke.
abstract: OBJECTIVE
  Collateral flow is associated with clinical outcome after acute ischemic stroke and may serve as a parameter for patient selection for intra-arterial therapy. In clinical trials, DSA and CTA are 2 imaging modalities commonly used to assess collateral flow. We aimed to determine the agreement between collateral flow assessment on CTA and DSA and their respective associations with clinical outcome.
  
  
  METHODS
  Patients randomized in MR CLEAN with middle cerebral artery occlusion and both baseline CTA images and complete DSA runs were included. Collateral flow on CTA and DSA was graded 0 (absent) to 3 (good). Quadratic weighted κ statistics determined agreement between both methods. The association of both modalities with mRS at 90 days was assessed. Also, association between the dichotomized collateral score and mRS 0-2 (functional independence) was ascertained.
  
  
  RESULTS
  Of 45 patients with evaluable imaging data, collateral flow was graded on CTA as 0, 1, 2, 3 for 3, 10, 20, and 12 patients, respectively, and on DSA for 12, 17, 10, and 6 patients, respectively. The κ-value was 0.24 (95% CI, 0.16-0.32). The overall proportion of agreement was 24% (95% CI, 0.12-0.38). The adjusted odds ratio for favorable outcome on mRS was 2.27 and 1.29 for CTA and DSA, respectively. The relationship between the dichotomized collateral score and mRS 0-2 was significant for CTA (P= .01), but not for DSA (P= .77).
  
  
  CONCLUSIONS
  Commonly applied collateral flow assessment on CTA and DSA showed large differences, indicating that these techniques are not interchangeable. CTA was significantly associated with mRS at 90 days, whereas DSA was not.
authors.affiliation: From the Departments of Radiology (I.G.H.J., O.A.B., M.E.S.S., C.B.L.M.M.) i.g.jansen@amc.nl.
authors.forename: I G H
authors.identifier: http://orcid.org/0000-0002-8862-1877
authors.initials: IGH
authors.lastname: Jansen
authors.affiliation: From the Departments of Radiology (I.G.H.J., O.A.B., M.E.S.S., C.B.L.M.M.).|Departments of Neurology (O.A.B.).
authors.forename: O A
authors.identifier: http://orcid.org/0000-0002-2212-6128
authors.initials: OA
authors.lastname: Berkhemer
authors.affiliation: Texas Stroke Institute (A.J.Y.), Plano, Texas.
authors.forename: A J
authors.identifier: http://orcid.org/0000-0002-7657-142X
authors.initials: AJ
authors.lastname: Yoo
authors.affiliation: Departments of Radiology (J.A.V.).
authors.forename: J A
authors.identifier: http://orcid.org/0000-0003-3614-9168
authors.initials: JA
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authors.affiliation: Departments of Radiology (G.J.L.N.).
authors.forename: G J
authors.identifier: http://orcid.org/0000-0001-6575-9868
authors.initials: GJ
authors.lastname: Lycklama À Nijeholt
authors.affiliation: From the Departments of Radiology (I.G.H.J., O.A.B., M.E.S.S., C.B.L.M.M.).
authors.forename: M E S
authors.identifier: http://orcid.org/0000-0001-6895-1353
authors.initials: MES
authors.lastname: Sprengers
authors.affiliation: Departments of Radiology (W.H.v.Z.).
authors.forename: W H
authors.identifier: http://orcid.org/0000-0003-1631-7056
authors.initials: WH
authors.lastname: van Zwam
authors.affiliation: Neurology (W.J.S.), St. Antonius Hospital, Nieuwegein, the Netherlands.
authors.forename: W J
authors.identifier: http://orcid.org/0000-0002-4070-9730
authors.initials: WJ
authors.lastname: Schonewille
authors.affiliation: Neurology (J.B.), Haaglanden Medical Center, The Haag, the Netherlands.
authors.forename: J
authors.identifier: http://orcid.org/0000-0002-8850-8225
authors.initials: J
authors.lastname: Boiten
authors.affiliation: Department of Radiology (M.A.A.v.W.), Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: M A A
authors.identifier: http://orcid.org/0000-0003-4895-229X
authors.initials: MAA
authors.lastname: van Walderveen
authors.affiliation: Neurology (R.J.v.O.), Cardiovascular Research Institute, Maastricht, the Netherlands.
authors.forename: R J
authors.identifier: http://orcid.org/0000-0003-1032-9099
authors.initials: RJ
authors.lastname: van Oostenbrugge
authors.affiliation: Radiology (A.v.d.L.), Erasmus MC University Medical Center, Rotterdam, the Netherlands.
authors.forename: A
authors.identifier: http://orcid.org/0000-0002-6159-2228
authors.initials: A
authors.lastname: van der Lugt
authors.affiliation: Biomedical Engineering and Physics (H.A.M.), Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: H A
authors.identifier: http://orcid.org/0000-0002-1414-6313
authors.initials: HA
authors.lastname: Marquering
authors.affiliation: From the Departments of Radiology (I.G.H.J., O.A.B., M.E.S.S., C.B.L.M.M.).
authors.forename: C B L M
authors.identifier: http://orcid.org/0000-0002-7600-9568
authors.initials: CBLM
authors.lastname: Majoie