title: Clot Burden and Collaterals in Anterior Circulation Stroke: Differences Between Single-Phase CTA and Multi-phase 4D-CTA.
abstract: OBJECTIVE
  It has been reported that the extent of intravascular thrombi and the quality of collateral filling in computed tomography (CT) angiography are predictive for the clinical outcome in patients with acute stroke. We hypothesized that multi-phase four-dimensional CTA (4D-CTA) allows better assessment of clot burden and collateral flow compared with arterial single-phase CTA (CTA).
  
  
  METHODS
  In 49 patients (33 female; age: 77 ± 12 years) with acute anterior circulation stroke, CTA and 4D-CTA reconstructed from dynamic perfusion CT data were analyzed for absolute thrombus length (TL), clot burden score (CBS), and collateral score (CS). The length of the filling defect was also defined on thin-slice nonenhanced CT as corresponding hyperdense middle cerebral artery sign (HMCAS) when present.
  
  
  RESULTS
  There was good correlation (r = 0.62, p < 0.01) between the length of HMCAS (1.29 ± 0.62 cm) and TL in 4D-CTA (1.22 ± 0.51 cm). 4D-CTA and CTA significantly varied (p < 0.01) in TL (1.42 ± 0.73 cm (CTA) versus 1.11 ± 0.62 cm (4D-CTA)), CBS (median: 5, interquartile range: 4-7 (CTA) versus median: 6, interquartile range: 5-8 (4D-CTA); p < 0.001), and CS (median: 2, interquartile range: 1-2 (CTA) versus median: 3, interquartile range: 2-3 (4D-CTA); p < 0.001). Accordingly, CTA significantly overrated clot burden and underestimated collateral flow.
  
  
  CONCLUSIONS
  4D-CTA more closely defines clot burden and collateral supply in anterior circulation stroke than CTA, implicating an additional diagnostic benefit.
authors.affiliation: Department of Neuroradiology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany. iris.kaschka@uk-erlangen.de.
authors.forename: I N
authors.initials: IN
authors.lastname: Kaschka
authors.affiliation: Department of Neuroradiology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany.
authors.forename: S P
authors.initials: SP
authors.lastname: Kloska
authors.affiliation: Department of Neuroradiology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Struffert
authors.affiliation: Department of Neuroradiology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Engelhorn
authors.affiliation: Department of Neuroradiology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Gölitz
authors.affiliation: Department of Neurology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Kurka
authors.affiliation: Department of Neurology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Köhrmann
authors.affiliation: Department of Neurology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Schwab
authors.affiliation: Department of Neuroradiology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Doerfler
mesh_terms: D000368:Aged; D000465:Algorithms; D020520:Brain Infarction / Q000150:complications / Q000000981:diagnostic imaging*; D002533:Cerebral Angiography / Q000379:methods*; D000072226:Computed Tomography Angiography / Q000379:methods*; D003937:Diagnosis, Differential; D005260:Female; D056973:Four-Dimensional Computed Tomography / Q000379:methods*; D006801:Humans; D020767:Intracranial Thrombosis / Q000000981:diagnostic imaging* / Q000209:etiology; D008297:Male; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: 4D computed tomography angiography; Collateral circulation; Perfusion imaging; Stroke; Thrombus