title: Carotid pseudo-occlusion on CTA in patients with acute ischemic stroke: a concerning observation.
abstract: OBJECTIVE
  Differentiation between an occluded and a patent extracranial internal carotid artery (ICA) is crucial in the diagnostic workup of patients with acute ischemic stroke; particularly in patients eligible for endovascular treatment. We report neurological and radiological findings of cases in which CTA in the acute phase incorrectly revealed an occlusion of the ICA.
  
  
  METHODS
  In our image data base of 54 patients with acute ischemic stroke eligible for endovascular treatment, we searched for patients with an occluded extracranial ICA on CTA whereas DSA proved that this artery was patent. Of these patients, all available images were re-examined to investigate possible causes of these so-called pseudo-occlusions.
  
  
  RESULTS
  We detected 6 patients (11%) with a pseudo-occlusion. The pseudo-occlusions on CTA were associated with reduced flow due to carotid T-occlusions (4 cases) or a combination of a high degree stenosis of the extracranial ICA and MCA occlusion (2 cases).
  
  
  CONCLUSIONS
  CTA in the acute phase of ischemic stroke needs to be interpreted with severe caution, and in endovascular treatment decisions we should be aware that an extracranial ICA occlusion may be a false positive finding.
authors: Department of Radiology, AMC, Amsterdam, The Netherlands. h.a.marquering@amc.uva.nl
authors: Henk A
authors: HA
authors: Marquering
authors: Paul J
authors: PJ
authors: Nederkoorn
authors: Ludo F
authors: LF
authors: Beenen
authors: Geert J
authors: GJ
authors: Lycklama à Nijeholt
authors: René
authors: R
authors: van den Berg
authors: Yvo B
authors: YB
authors: Roos
authors: Charles B
authors: CB
authors: Majoie
mesh_terms: D000368:Aged; D002545:Brain Ischemia / Q000000981:diagnostic imaging*; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D002533:Cerebral Angiography; D016208:Databases, Factual; D057510:Endovascular Procedures / Q000379:methods*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012189:Retrospective Studies; D020521:Stroke / Q000000981:diagnostic imaging*; D017131:Thrombectomy; D015912:Thrombolytic Therapy; D014057:Tomography, X-Ray Computed
keywords: Acute ischemic stroke; CT angiography; Endovascular treatment; Hemodynamic flow