title: Perfusion-Derived Dynamic 4D CT Angiography Identifies Carotid Pseudo-Occlusion in Hyperacute Stroke.
abstract: Differentiation between true acute tandem occlusion involving the extracranial internal carotid artery (ICA) from pseudotandem occlusion with a patent extracranial ICA has important prognostic and therapeutic implications. We explored the utility of perfusion-derived 4-dimensional CT angiogram (4D-CTA) in identifying carotid pseudo-occlusion in a single-center pilot study.
  
  
  
  Acute stroke patients with delayed antegrade ICA flow on 4D-CTA despite an apparent tandem occlusion on conventional single-phase CTA were prospectively identified over a 2.5-year period (2013-2015).
  
  
  
  Eight patients were identified. Delayed antegrade intracranial flow from the apparently occluded ICA was detected up to 50 seconds after contrast administration on 4D-CTA. The distal intracranial ICA was the most common site of true occlusion. Reconstruction of the 4D-CTA images required an additional processing time of 2-3 minutes.
  
  
  
  4D-CTA is a novel noninvasive technique that can identify carotid pseudo-occlusion in the acute stroke setting. Our preliminary findings suggest that 4D-CTA can be easily incorporated into an existing acute stroke neuroimaging protocol.
authors.affiliation: Department of Neurosciences, Box Hill Hospital, Melbourne, Victoria, Australia. ng.fcffelix@gmail.com.
authors.forename: Felix C
authors.initials: FC
authors.lastname: Ng
authors.affiliation: Department of Neurosciences, Box Hill Hospital, Melbourne, Victoria, Australia.|Eastern Health Clinical School, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia.
authors.forename: Philip M C
authors.initials: PM
authors.lastname: Choi
authors.affiliation: Department of Medical Imaging, Box Hill Hospital, Melbourne, Victoria, Australia.
authors.forename: Mineesh
authors.initials: M
authors.lastname: Datta
authors.affiliation: Department of Neurosciences, Box Hill Hospital, Melbourne, Victoria, Australia.|Eastern Health Clinical School, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia.|Epworth Eastern Neurosciences Unit, Epworth Research Institute, Box Hill, Melbourne, Victoria, Australia.
authors.forename: Amanda
authors.initials: A
authors.lastname: Gilligan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging*; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging*; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging*; D000072226:Computed Tomography Angiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D010865:Pilot Projects; D020521:Stroke / Q000000981:diagnostic imaging*
keywords: 4D-CTA; CT perfusion; Carotid pseudo-occlusion; acute stroke; endovascular intervention